Scipedia: Documents published in 2021

Evaluation on the Potential Use of Pulverized Natural Subbase Dust as Alternative Filler Material for Hot Mix Asphalt Design, Jimma Town

Emer T. Quezon — Sat, 06 Mar 2021 14:10:02 +0100

A well-designed asphalt mixture is expected to serve effectively for many years under a variety of loading and environmental conditions. Bituminous concrete is one of the highest and costliest types of flexible pavement. One of the main problems in the construction of asphalt paving mixture is obtaining a sufficient amount of filler material and the high cost of the use of ordinary Portland cement, hydrated lime, or marble dust as filler material. Asphalt Institution restricted the use of a maximum limit of 2% proportion to improve the aggregates adhesion properties only, which is not sufficient quantity to achieve the grading requirements. To alleviate this problem, it is important to come across alternative filler material that can be used in more quantity. The study has investigated the potential use of natural subbase dust (MSD)as alternative filler material, and their characteristic on the effect of hot asphalt mixture was identified. This research was conducted by using Experimental Research Design. In total, 48 samples were prepared according to ASTM D1559, of which 15 of them used to calculate the OBC and the rest to find out the effects of adding different percentages of NSD to the asphalt mixture. For this purpose, five different bitumen contents were used (4%−6% with 0.5% increments). Aggregate mixtures blended without filler and with NSD filler were investigated to evaluate their Marshall properties on HMA mixtures. Four varying percentages of NSD ranging from (2% - 8% at 2% increments) were used for Marshall experiments. And for the control mix, 2% hydrated lime (HL) and 2% ordinary Portland cement used in the mixture besides, 4% Marble Dust was used as a reference. The aggregates were blended by using the Job mix formula to obtain the percentage of material proportion. As a result for aggregates blended without filler G-1 (26%), G-2 (23%), and G-3 (51%) proportion were used whereas for aggregates blended with NSD filler, G-1 (26%), G-2 (22%), G-3 (46%) and G-4 (6%) was utilized. Where G-1 is Coarse Aggregate 3/4, G-2 is Intermediate Aggregate 3/8, G-3 is Fine Aggregate, and G-4 is NSD filler. Based on Marshall's test results, the OBC was found 5.1% by the total asphalt mix. Furthermore, examining Marshall mixes containing different percentages of filler showed the optimum percentage of NSD was 6%. The Marshall properties of the experiments at 6% NDS filler resulted in high stability, low flow, lower VFB, low VMA & lower air voids that are consistent with the standard specifications. The investigation of NSD filler has resulted in good effects on the Marshall properties of the asphalt mixture. Furthermore, the outcome of Marshall parameters like stability, air voids, and bulk density values was consistent with the standard specifications. Therefore, NSD filler can potentially be used as an alternative filler material in HMA with optimum filler content of 6%. Besides, it is recommended to exercise the use of NSD as filler material in HMA projects in order to ensure the quality of works, save transportation costs and save time spend importing other filler materials from far away. It is also recommended combining NSD filler with other materials may produce a better outcome on the effects on the asphalt mix properties.

EFFECTS ON MODIFIED PROPERTIES OF EXPANSIVE CLAY SOIL USING WASTE HOLLOW CONCRETE BLOCK (HCB) AND CEMENT PLASTER WASTE MATERIALS FOR SUBGRADE CONSTRUCTION

Emer T. Quezon — Sat, 06 Mar 2021 14:05:02 +0100

Expansive soils characterized by changing its volume and strength due to seasonal variations. Due to this volume changes, expansive clay soil caused many problems in road construction and is relatively common in Ethiopia. As a result, such types of soil are not adequately for road construction, which requires proper attention. The focus of this study was to improve the engineering properties of the expansive clay soil with the addition of waste materials to use as a subgrade construction material. Soil samples were taken from three locations within the study area and performed laboratory tests for the moisture content, specific gravity, free swelling, Atterberg limit, and compaction test on its natural state. The expansiveness of the soil from the three locations were determined. The highest value of expansiveness from these samples considered for the experiment by the addition of waste materials concentration with 5%, 10% 20%, and 30% by weight. Test results indicated that the moisture content, free swelling, specific gravity Atterberg limit decreased, while the maximum dry density increased as the concentration of waste material increase. Hence, the minimum amount of waste materials comprised of 10% that will improve the strength of expansive clay soil for use in road subgrade construction.

. Effects of Poor Workmanship on Building Construction and Its Implication to Project Management Practice: A Case Study in Addis Ababa City

Emer T. Quezon — Sat, 06 Mar 2021 14:01:03 +0100

sup>— The construction of building structure involves very complicated undertakings. It requires a trained workforce at the design stage, approval process, supervision, and construction stages. Inferior quality of workmanship is one of the significant issues facing the workforce to perceive and apply the proper construction methods and techniques following the quality control assurance for building projects. This study considered some of the construction stakeholders participated in the implementation of projects in Addis Ababa City. It focused on assessing and investigating poor workmanship on the quality of projects that included concreting works to accessible ongoing construction sites across the study area. It involved determining the cause of low-level workmanship and identifying factors that would significantly minimize the problems and increase client satisfaction. The study comprised of 20 construction sites, of which 55 questionnaires were collected. The data collected are related to the challenges facing the construction industry and concrete quality as well. The causes and strategies applied to improve construction quality were analyzed using the study's variable. Results indicated that inadequate construction management represented a low level of workmanship and a lack of training rated first with RII of 0.9556. At the same time, the Workers' motivation was placed second with RII 0.775. Hence, it recommends close observation of construction management factors like supervision, training, motivation, and good communication on-site to minimize the cost and effects associated with poor workmanship when implementing building projects.

Effect of Partial Replacement of Crushed Stone Dust Filler with Waste Glass Powder in Hot Mix Asphalt Concrete Production

Emer T. Quezon — Sat, 06 Mar 2021 13:53:02 +0100

The use of waste recycled materials in road construction nowadays is considered a positive means of providing improved pavement performance. This research focused on evaluating the effect of waste glass powder as a partial replacement of crushed stone dust filler in hot mix asphalt. Three hot mix asphalt samples were produced using crushed stone dust of 5%, 6.5%, and 8% as mineral filler with five different bitumen content of 4%, 4.5%, 5%, 5.5%, and 6%, respectively. From the preliminary series tests of asphalt contents, a 6.5% crushed stone dust filler selected, providing the highest waste glass powder stability. The content of crushed stone dust filler was replaced with a rate of 0%, 25%, 50%, 75%, and 100% to test Marshal stability to obtain the Optimum bitumen content and Optimum filler content. Results indicated at 75% replacement of crushed stone dust with waste glass powder at 5.10% bitumen content, 12.0kN Marshall stability value, 2.84mm Flow value, 4.0% Air voids, 72.3% VFB, and 2.360g/cm3 Bulk density. Hence, the mixture of 75% waste glass powder by weight of crushed stone dust filler meets the minimum requirements of the Ethiopian Road Authority and Asphalt Institute Specifications.

The ECO-COMPASS EU-China Project

Scipedia content — Thu, 04 Mar 2021 08:59:40 +0100

Fibre reinforced polymers are important materials used in aviation due to their
excellent specific properties enabling the reduction of fuel consumption. For example, carbon
fibre reinforced epoxy resins are used in fuselage and wing structures. Glass fibre reinforced
phenolic resins are mainly used for the interior panels due to their low weight and favourable
fire properties. All these composite materials used in aviation have one thing in common: they
are man-made. Renewable materials like bio-fibres and bio-resins are under investigation for
a long time for composites but they did not made it into modern aircraft in high amounts yet.
The project ECO-COMPASS under Horizon 2020 aims to bundle the knowledge of 17
partners from China and Europe to develop ecological improved composites for the use in
aircraft interior and secondary structures [1]. Bio-based reinforcements, epoxy resin and
sandwich cores are developed and improved for their application in aviation. Furthermore the
use of recycled carbon fibres to increase the mechanical strength and multifunctional aspects
of bio-composites are evaluated. In order to withstand the special stresses in aviation
environment, protection technologies to mitigate the risks of fire, lightning and moisture
uptake are under investigation. An adapted modelling and simulation will enable the
optimization of the composite design. Electrical conductive composites for electromagnetic
interference shielding and lightning strike protection are under investigation in ECOCOMPASS as well. The cooperation includes the exchange of knowledge and materials in
order to optimize the development of ecological friendly composites.

Development of Multifunctional Materials and Structures with Improved Capacities in Aerodynamics, De-icing, Acoustics or Electromagnetism for Civil and Military Aircrafts

Scipedia content — Thu, 04 Mar 2021 08:59:28 +0100

For several years, either in the frame of research projects (French, European), or for direct
application on aircraft programs, Dassault Aviation has developed multifunctional materials
and structures (MMS) with specific benefits in aerodynamics, de-icing, acoustic or
electromagnetisms. The main challenge is to get the best compromise between the high
functional performances desired and the mechanical and aeronautic environment resistance
needed for the application. This presentation will review some examples of development
performed in the recent years for aircraft aerodynamics improvement, icing protection,
acoustics and new antenna radomes.

New Enhanced Acoustic Damping Composite Material for the Aeronautics Industry

Scipedia content — Thu, 04 Mar 2021 08:59:16 +0100

The present article investigates an innovative structural composite material concept
with the additional functionality of acoustic damping. It is achieved by introducing an
embedded elastomeric layer within the composite laminate, which constitutes a constrained
layer damping (CLD) system. The main objective is to increase the acoustic performance of
the baseline material, while its mechanical properties are maintained. In addition, material
processability and inspectability have been considered as important drivers for the technology
development. In order to identify the most promising candidate, a set of alternatives has been
explored and analysed, giving rise to a compromise solution between the enhanced acoustic
performance and the structural properties of the baseline material.

Automated Manufacture of Grid Stiffened Panels

Scipedia content — Thu, 04 Mar 2021 08:58:58 +0100

Rib or grid stiffened structures have been investigated for decades, mainly for
application in space structures.
Grid structures offer the possibility to develop more damage tolerant structures as the
network of ribs can provide redundant load paths. In an ideal situation, an aircraft fuselage
could have a load carrying grid with ribs that carry tensile, compressive and shear loads. The
skin would only need to sustain the cabin pressure load.
Such a configuration could lead to significant weight reduction as a different design
philosophy can be used. Typically, a damage tolerant design approach allowing a maximum
of 3000 µstrain is used for composite aircraft structures. Using a grid structure, a different
approach could be developed for a design which could allow strains up to 6000 µstrain.
Automated fibre placement has made composite grid structures an affordable option.
However, they pose a major challenge in the development of tooling for cure due to their
complex and sometimes irregular structure.
Within the European funded Horizon 2020 ACASIAS programme, square antenna elements
are developed to be integrated in a composite aircraft fuselage panel. For this reason, an
orthogrid stiffener pattern was chosen. As the skin of the panel must be transparent for the
antenna signals, a glass fibre skin is required. A glass fibre skin to carry shear loads and
carbon fibre ribs to carry compression and tension loads is therefore being developed to be
able to meet structural and electromagnetic requirements.
This paper describes aspects of the ongoing development for the design, manufacture and
testing of an orthogrid stiffened structure in an efficient way.
Simple alternating cutting of tapes at the crossing appear to be a suitable solution with a
tensile stiffness reduction of 10 % compared to the situation without cuts. These and other
details and elements are tested to validate the final design.
The use of reusable silicone vacuum bags was investigated in order to replace complex
metal tooling blocks. Besides saving on mould materials and machining, the use of a preshaped silicone vacuum bag is expected to reduce labour cost due to a decrease in handling
of tooling blocks for positioning and cleaning.
The first trial indicates that good quality laminates can be obtained using reusable vacuum
bags. More testing will be carried out to validate the concept for a large 3×1.2 m panel.

Electrical Conductivity and Electromagnetic Shielding Effectiveness of Bio-Composites

Scipedia content — Thu, 04 Mar 2021 08:58:35 +0100

In this paper, electrical conductivity and electromagnetic shielding effectiveness of
two bio-composites have been studied by tests and numerical models. Two monolithic
composites with partly bio-based content were manufactured. The first bio-composite is made
of a carbon fibre fabric prepreg and a partly bio-based (rosin) epoxy resin (CF/Rosin). The
second bio-composite is a combination of prepregs of carbon fibre fabric / epoxy resin and flax
fibre fabric / epoxy resin (CF-Flax/Epoxy). A single line infusion process has been used prior
to the curing step in the autoclave. Both variants are exemplary for the possibility of introducing
bio-based materials in high performance CFRP. In-plane and out-of-plane electrical
conductivity tests have been conducted according to Airbus standards AITM2 0064 and AITM2
0065, respectively. Electromagnetic shielding effectiveness tests have been conducted based on
the standard ASTM D 4935-10. Materials were prepared at the German Aerospace Center
(DLR) while characterization tests were conducted at the University of Patras. In addition to
the tests, numerical models of representative volume elements have been developed using the
DIGIMAT software to predict the electrical conductivity of the two bio-composites. The
preliminary numerical results show a good agreement with the experimental results.

Structural Analyses of Orthogrid Fuselage Panel for Integrated Ku-band SatCom Antenna.

Scipedia content — Thu, 04 Mar 2021 08:58:09 +0100

The aim of this work is to describe the structural analysis of a multifunctional aircraft
fuselage panel. The structure of the panel has an embedded antenna tiles. The panel consists
of UniDirectional (UD) carbon fibre reinforced composite skin stiffened with ortho-grid ribs,
and a transparent skin window made using UD glass fibre reinforced composite. The orthogrid structure is a structural reinforcement but also the antenna tiles support. The presented
work proposes a numerical multiscale strategy. The laminate is simulated with solid elements,
in order to capture the real kinematics of the material, but several laminas are condensed in
a single finite element. The performance of each lamina is obtained using the Serial-Parallel
(SP) mixing theory. The specific formulations developed have been very useful to identify and
study the mechanical performance of these new structures and the localization of unknown and
un-predicted hot-spots in the structure.

Functionalization of Carbon Nanotubes and Mechanical Characterisation of Bio-based Epoxy Nano-composites

Scipedia content — Thu, 04 Mar 2021 08:57:40 +0100

Chemical functionalization of multiwalled carbon nanotubes (MWCNTs) is important from the view
point of polymer based composite manufacturing. As pristine MWCNTs has certain disadvantage such
as they have lower dispersion, they are hydrophobic and are not readily soluble in a solvent, these
characteristics makes them unreliable candidate for most of the industrial applications. By doing
chemical functionalization of MWCNTs, these shortcomings can be overcome, and the MWCNTs can
be used as a filler in composite manufacturing. This has the advantage of better nanofillers’ dispersion
and provide the better interfacial bonding.
In this study, MWCNTs are functionalized by the carboxylic group, chemical functionalization of
MWCNTs is an optimization problem, governed by parameters like mixture acid concentration,
temperature, time of heating and amount of MWCNTs used. Material characterization of MWCNTs is
done and test specimens are manufactured according to different concentrations of MWCNTs within a
bio-based epoxy resin. Mechanical properties are then compared according to different concentrations.
These mechanical and material characterizations increase the understanding of chemical
functionalization by carboxylic group and the influence of the concentration of MWCNTs dispersed
within the bio-based resin matrix.

Comparision of Density Measurement Methods for Unidirectional Flax-Epoxy Polymer Composites

Scipedia content — Thu, 04 Mar 2021 08:56:46 +0100

Density is a decisive factor in determining one of the most important advantages
of flax fiber-reinforced polymer (FFRP) composites, i.e. their relatively low weight leading to
high specific properties. As a fundamental physical property of composites, density enters in
many engineering design and quality control calculations and its value is a determining factor
for several applications. Especially, we need precise material properties including density so
as to develop efficient numerical models to these materials. In this work, three density
measurement methods were evaluated and compared: Helium-gas pycnometry and Archimedes
with two different immersing liquids, water and ethanol. The results show that Helium-gas
pycnometry and Archimedes with ethanol gave similar and repeatable results, whereas using
water resulted in much lower values. The density values were all in the range of reported values.
However, Helium-gas pycnometry or Archimedes using ethanol are recommended for more
precision in measuring the density of FFRP composites.

Integrating Electromagnetic Functions into Fiber Metal Laminates – the Structural Challenge

Scipedia content — Thu, 04 Mar 2021 08:56:32 +0100

This paper outlines aspects, outcome and prospects of full integration of antennas into structural
elements of aircraft, from a structural design perspective.

Exploration of Radiating Aerostructures Ultimate Antenna and Structure Integration

Scipedia content — Thu, 04 Mar 2021 08:56:18 +0100

Two antenna designs are described that are both fully integrated into Fiber Metal
Laminate fuselage panels. Full integration in this context means that the antennas are flush with
the fuselage skin on the outside of the aero structure, while maintaining the structural properties
of the FML panel. The antennas are designed to resonate at GNSS and at VHF frequency bands.
Design considerations are discussed and preliminary results are presented.

Design Consideration for Fully Embedded Electronically Steerable SatCom Airborne Antenna

Scipedia content — Thu, 04 Mar 2021 08:55:58 +0100

In this paper a conceptual design of a SATCOM On The Move (SOTM) system in
the Ka band is presented. This system is intended to be airborne and fully integrated in an
AIRBUS C295 Flight Test Bench. The system relies in two separated low profile TX and RX
antennas (about half a meter size) which reach up to 10Mbps return link and 50Mbps forward
link.

Structural Integration of a Ku-band SatCom Antenna into Novel Fuselage Panel

Scipedia content — Thu, 04 Mar 2021 08:55:41 +0100

This paper addresses the structural integration of a Ku-band SATCOM antenna in
the fuselage of an aircraft. The phased array antenna consists of 25 antenna tiles that are
integrated in an orthogrid fuselage panel. The specific electromagnetic aspects of the antenna integration will be discussed in this paper; this concerns the lightning protection of the antenna tiles and the electromagnetic interaction of the CFRP orthogrid and GFRP fuselage skin with the array antenna. The structural properties and thermal management of the antenna will be discussed in separate papers [1,2,3].

Analysis of Radar Absorbing FSS on Foldcores and Honeycombs

Scipedia content — Thu, 04 Mar 2021 08:55:25 +0100

The objective of the paper is to investigate the radar absorption of honeycombs and
foldcores with printed conductive patterns. These structures can be manufactured by first
printing conductive Frequency Selective Surfaces (FSS) on planar substrates, which then can be used to shape foldcores and honeycombs by means of specific manufacturing technologies.
Foldcores can be considered as intermediate shapes between planar sheets (where the printed
patterns are perpendicular to the impinging radar waves) and honeycombs (where the printed
patterns are parallel to the impinging radar wave). It is shown that the radar absorbing
properties of the design strongly depend on the electrical conductivity of the paint, the size of
the printed patterns and the orientation of the printed patterns with respect to the impinging
wave. It is shown that a planar FSS has a maximum absorption of 50%, while foldcores and
honeycombs may obtain a higher absorption due to the fact that the patterns are orientated
under an angle with respect to the propagation direction of the wave.

Towards Multi-objective Design of EV-55 Winglet with Integrated VHF Antennas

Scipedia content — Thu, 04 Mar 2021 08:55:04 +0100

The article is devoted to highlight the challenges, bottlenecks and possible
solutions of VHF antenna integrated into a winglet from both the designer‘s and the
airframer‘s perspective. We look into pros and cons specific for different antenna solutions
and discuss ways how to protect them against possible electromagnetic environmental effects.
As an outlook, a winglet with integrated VHF notch antenna designed within the ACASIAS
project will be described in better detail.

Textile-Integrated Transmitting Unit

Scipedia content — Thu, 04 Mar 2021 08:54:44 +0100

This contribution deals with the main parts of the textile-integrated transmitting
unit, a transmitter and an antenna, operating in the ISM 5.8 GHz band. The transmitter is
based on commercially available WLAN UART Serial Port OWS451 and it is controlled via
the UART interface by microprocessor ATmega328. The antenna is based on the circular
ring-slot concept and it is able to provide monopolar radiation pattern to ensure maximum
coverage of the unit. The unit will be integrated in a seat cover and it will transmit the
telemetry of sensors integrated in the seat (temperature, pressure…).

Cooling of Active Components in Structurally Integrated Phased Arrays Antennas

Scipedia content — Thu, 04 Mar 2021 08:54:27 +0100

This paper presents an innovative cooling solution for active phased array antennas,
using a 3D printed liquid cooling device integrated in the structure’s PCB.

Manufacturing Aspects of Active Acoustic Lining panel

Scipedia content — Thu, 04 Mar 2021 08:54:12 +0100

This paper shows the technical aspects and the progress of manufacturing a lining
concept with actuators and sensors for noise reduction within the cabin of aircraft with CROR
engine. The structural integration, the repair possibilities and the serial production of such a
lining are focused.

From Design Towards Manufacturing of Winglets with Integrated VHF Antenna

Scipedia content — Thu, 04 Mar 2021 08:53:50 +0100

This paper shows the technical aspects and the progress of manufacturing a winglet concept with integrated VHF antenna.

Contribution of Conformal Antennas Towards Sustainable Aircraft

Scipedia content — Thu, 04 Mar 2021 08:53:24 +0100

This paper shows the drag and emission reduction potential of integrated, flush communication antennas at the surface of an airliner. The CFD simulations of the aircraft model representing a modern airliner with radome in different locations on its upper part of the fuselage have been done. The results have been compared with the baseline configuration of the aircraft without radome. The aerodynamic equivalent weight penalty and additional fuel needed due to the drag of the radome and its weight itself have been calculated by two approaches. The obtained drag reduction potential has been used for the estimation of the CO₂ and NO_x emissions reduction by using integrated antenna.

Remote Sensing for a Lining Integrated Active Structural Acoustic Control System

Scipedia content — Thu, 04 Mar 2021 08:53:05 +0100

In the framework of the EU project ACASIAS an aircraft sidewall panel (lining) with structurally integrated actuators and sensors is developed. Each lining has a digital unit which samples the sensor signals, performs filtering operations and supplies the actuators with control signals. The whole system makes up an active structural acoustic control system aiming at the reduction of low-frequency multi-tonal aircraft interior noise. The novelty of this approach compared to past implementations of active noise control (ANC) systems in aircraft is its modularity. Each so-called smart lining is autonomous in the sense that it processes only structural sensor data from its own integrated sensors. The use of external microphones for error sensing is avoided because this conflicts with the modularity of the smart lining. Hence, one important design task is the replacement of the physical error microphones by the integrated structural sensors and an acoustic filter (observer) running on the digital unit. This method, which is called the remote microphone technique for active control, has never been applied to an aircraft interior structure so far. The detailed design of the smart lining module comprises several steps which are taken within work package 3 of the ACASIAS project. Experimental data of an aircraft typical double panel system is captured in a sound transmission loss facility. The system is excited with a loudspeaker array placed directly in front of the fuselage structure. Different acoustic load cases are used for the definition of the sensors and the actuators. A multi-tonal excitation with high sound pressure level is relevant for the actuator dimensioning and a broadband excitation with multiple independent sound sources is relevant for the sensor definition. 19 accelerometers are mounted on the lining and 20 microphones are placed in front of it. All sensor signals are sampled simultaneously for deterministic and broadband load cases. The lining is equipped with two inertial mass actuators which are used for the active control. Measured frequency response functions of actuators at 39 positions are used for the optimization of the actuator locations. The measurement data is also used for the derivation of an observer and for the simulation of a smart lining with remote microphones. In this contribution, the steps undertaken for the detailed design will be described and simulation results of the noise reduction performance of the smart lining with remote microphones will be presented.

Towards a Lining Integrated Active Structural Acoustic Control System

Scipedia content — Thu, 04 Mar 2021 08:52:06 +0100

For future aircraft counter-rotating open rotor (CROR) engines are a promising technology to reduce their CO₂ footprint. Since the contribution of CROR engines to the cabin noise is higher than for jet engines, new strategies for the reduction of noise transmissions for frequency bands below 500 Hz are necessary. Active structural acoustic control (ASAC) systems are capable to reduce sound transmission of lining structures in this bandwidth. Sensors measure the vibrations of the lining to estimate its sound emission into the cabin. Based on these signals a controller calculates force signals for actuators on the lining. The actuator forces change the vibration behaviour of the lining in order to reduce its sound emission. For the realization of such a system in a real aircraft, manufacturing and maintenance issues have to be addressed. Within work package 3 of the EU project ACASIAS an aircraft lining with an integrated ASAC system is developed. The size of the lining is app. 1300 x 1690 mm² (W x H) and it is simply curved. The radius of 2980 mm makes it relevant for a twin-aisle aircraft like the Airbus A350. The focus of research activities lies on the integration of components and the industrial manufacturing process of the lining. The components to be integrated are sensors, actuators and the corresponding wiring. A concept is proposed where each actuator and sensor is encapsulated in a kind of insert. The inserts smoothly integrate into the manufacturing process of the lining while they protect the actuators and sensors from humidity, dust, etc. The maintenance aspect is covered by the option to change each actuator or sensor upon insert level. The integrated wiring of the lining is left unaffected during an actuator or sensor replacement since connectors in each insert allow a nearly tool-free assembly/disassembly. In this paper the progress of work package 3 is presented at a detailed design review (DDR) stage. Finally, the lining will be manufactured and equipped with a full ASAC system. Experiments will be conducted in the acoustic transmission loss facility at the DLR.

Impacts of Climate Change on Ports: Current Levels of Preparedness.

Raúl Cascajo — Wed, 03 Mar 2021 12:02:02 +0100

This paper displays the results obtained through exploratory research carried out through an online form that sought to assess the level of preparation of ports and port terminals in the face of climate change. This work was developed with the intention of complementing and continuing the research carried out by UNCTAD 2018 and published under the name UNCTAD Research Paper nº 18. That work identified biases due to the low number of participating ports in the South American and Caribbean region. This research was conducted with the objective of filling this gap. This paper also highlights the main differences between the two studies.

Wave Energy Assessment at Valencia Gulf and Comparison of Energy Production of Most Suitable Wave Energy Converters

Raúl Cascajo — Wed, 03 Mar 2021 11:53:02 +0100

eaports’ energy strategy should rely on the use of renewable energy. Presently, the share of renewable energy used by many of the ports worldwide is negligible. Some initiatives are in the process of implementation to produce some of the energy used by the Port of Valencia, one the largest ports in the Mediterranean Basin. Among these initiatives, a photovoltaic plant with an installed capacity of 5.5 MW is under a tendering process and the assessment studies for the deployment of three to five windmills are close to being finished. However, this is not enough to make it a “zero emissions port” as some of the energy demand would still be covered by fossil fuels. Therefore, we should consider clean alternative energy sources. This article analyses the wave energy resources in the surroundings of the Port of Valencia using a 7-year series of data obtained from numerical modelling (forecast). The spatial distribution of wave power is analysed using data from 3 SIMAR points at Valencia Bay and is compared to the data obtained by the Valencia Buoy I (removed in 2005). The obtained results are used to estimate the power matrices and the average energy output of two wave energy converters suitable to be integrated into the port’s infrastructure. Finally, the wave energy converters’ production is compared to the average amount of energy that is forecast to be obtained from other renewable sources such as solar and wind. Due to the nature of the Gulf’s wave climate (mostly low waves), the main conclusion is that the energy obtainable from the waves in the Valencia Gulf will be in correlation with such climate. However, when dealing with great energy consumers every source of production is worthwhile and further research is needed to optimize the production of energy from renewable sources and its use in an industrial environment such as ports.

Correlation Analysis of Factors Affecting Shoring Construction Techniques in Central Business District of Addis Ababa, Ethiopia

Emer T. Quezon — Mon, 01 Mar 2021 20:38:02 +0100

Recent urbanization of central parts of Addis Ababa has necessitated the use of deep excavations for the foundation of highrise buildings and related infrastructure projects. The conditions of the subsoil, the safety of neighboring structures, groundwater conditions, experience by contractors, working space, the effect of vibration, and noise must be considered for the choice of deep excavation support system. Besides, economic factors, local availability of equipment, and technical staff are also governing factors for choosing an appropriate shoring technique. The study focused on the major construction methods and techniques of shoring works in Addis Ababa, Ethiopia. Only four projects utilized shoring construction techniques from the total number of high-rise buildings available in the City. The target population included a minimum of twenty respondents from the four construction sites constructed around Beherawi, Lideta sub-city in Addis Ababa. Two of the projects were supervised by Specialists from Varnero Foundation and Meseret Foundation PLC. Primary and secondary data are gathered to support the objective of the study. All the frequency distribution, Reliability, and Pearson correlation were analyzed using SPSS. All groups of factors that affect shoring construction were ranked using the Relative Importance Index (RII). Results indicated that geotechnical investigation, building type, and excavation depth were the major factors with an RII value of 0.89 and 0.86, respectively. Besides, the analyses showed that were strong correlations between the different factors within each group of factors in undertaking the shoring construction. Hence, it is suggested to take a deep and detailed sub-soil investigation to determine the suitability of shoring materials, appropriate construction methods, and techniques.

Expert Choice-Based Approach on Analytical Hierarchy Process for Pavement Maintenance Priority Rating Using Super Decision Software in Addis Ababa City, Ethiopia

Emer T. Quezon — Mon, 01 Mar 2021 20:15:02 +0100

Untimely maintenance activities resulting from budget fluctuations and improper prioritization can lead to further pavement deterioration. Selecting the most cost-effective maintenance activities to control and minimize road users' risk under current budget constraints is necessary. The study tried to fill the gap that decision-makers in Addis Ababa City Road Authority often performed pavement repair and maintenance without considering a systematic procedure. Ten road sections selected that are planned for pavement maintenance in the study area. The most dominant distresses ranked in Decision Analysis Module in Excel, including road class, weights for each criterion, and sub-criteria obtained using the Analytical Hierarchy Process approach and calculated in Super Decision Software for maintenance prioritization. Results indicated that the developed analytical hierarchy process model works sufficiently and yields adequate output for providing accurate decisions. Hence, considering the multi-criteria to prioritize the pavement sections for maintenance, this model can give affirmative action for the decision-maker.

Effect of Selected Conventional and Non-conventional Mineral Fillers with ‘Enset’ Fibers on Compaction Characteristics of Stone Mastic Asphalt Pavement (SMAP)

Emer T. Quezon — Mon, 01 Mar 2021 20:06:02 +0100

The content and type of ingredient materials are used to prepare the asphalt mix to affect the pavement surface's quality. This study aimed to investigate the compaction characteristics of Stone Mastic Asphalt Pavement (SMAP) mix using two different types of mineral fillers; namely, crushed stone and Ambo sandstone dust with local material enset fiber. Results indicated that the filler type and the content with or without fiber have a great effect on compaction characteristics of Stone Mastic Asphalt Pavement. The test results also showed that the addition of enset fiber in asphalt mix increases density, compaction energy, and strength of asphalt mix and reduces Marshall flow of the mixes. Besides, crushed stone dust and Ambo sandstone dust with enset fiber affect the Marshall property and compaction characteristics of the stone mastic asphalt mix differentially. The Ambo sandstone dust filler has a low density and has high binder absorption capacity compared with crushed stone dust filler in SMA mixes. In this study, the optimum binder content for the mixture by using Ambo sandstone dust (8%, 6.41%), (8.5%, 6.48%) & (10%, 6.43%) as well as the mixture using crushed stone dust filler at (8%, 5.84%), (8.5%,6.32%) & (10%,5.96%) was determined. The optimum fiber content obtained at 0.3% suggests that using enset fiber in stone mastic asphalt mixture improves the strength of asphalt pavements to resist external loads. The enset fiber at 0.3% better modifies stone mastic asphalt pavement properties. Finally, it is postulated that the performance of pavement is affected by filler type and content. Simultaneously, the Marshall property has a linear relationship with compaction characteristics. It showed the possibility of constructing stone mastic asphalt pavement in Ethiopia by using locally available materials.

Experimental Study on Application of Marble Waste as Conventional Aggregate for Base Course Materials

Emer T. Quezon — Mon, 01 Mar 2021 19:54:02 +0100

Recently, highway and construction industries utilize a substantial quantity of conventional aggregates. The increasing demands for conventional aggregate cause an increase in the cost of construction, reduction of natural resources, and continuing deterioration of the earth's surface. On the other hand, the waste generated from the marble industries during the process of cutting and polishing was increasing day by day all over the world. In Ethiopia, the use of Marble Waste Aggregate materials in road construction as a base course material was not well-known, and it was simply wasted at every place where the marble production was continuing. Therefore, this paper focused on evaluating the possibility of using marble waste aggregate as conventional aggregate in the base course layer of flexible pavements by experimental method. To achieve the objectives of the research, mechanical stabilization and laboratory tests have been carried out at different percentage replacement of Conventional Aggregate by (0%, 20%, 40%, 50%, 60%, 80%, and 100%) of Marble Waste Aggregate weights. Marble wastes materials are collected from Burayyu city, Alisha marble processing industry. The laboratory test results for MWA indicated SG, ACV, AIV, LAA, Flakiness Index , Elongation Index, Plastic Index, Water Absorption, and CBR of 2.74%, 23.63%, 26.21%, 27.03%, 26.48%, 13.29%, Non Plastic, 0.50% and 73.3%, respectively. These test results fulfilled the ERA standard specification for some tests, and they showed marginal quality values to the standard specification for GB2 and GB3 base course materials. CBR and gradation test results shown failure to meet the standard specification. Thus, mechanical stabilization was done to improve the mechanical and physical properties of the Marble Waste Aggregate. Blending of 80%MWA with 20% CA results in SG, ACV, AIV, LAA, Flakiness Index, Elongation Index, Plastic Index, Water Absorption, and CBR of 2.83%, 18.2%, 21.52%, 22.58%, 23.79%, 16.29%, Non Plastic, 0.80%,and 82.5% respectively. At this proportion, the gradation also observed to fit with the required ERA standard specification of GB2 and GB3 materials. Therefore, the use of marble waste aggregate up to 80% by weight is recommended for the road base course layer, when it is found near to the construction site and in places where the materials are abundantly available.

Ciencia en Revolución

Revista Ciencia en Revolución — Mon, 01 Mar 2021 18:38:02 +0100

Ejemplar volumen 6, Número 17, abril de 2000 de la revista digital Ciencia en Revolución, editado por el Centro Nacional de Tecnología Química.

Analysis of influential factors affecting workers’ productivity on highway construction projects during Covid-19 pandemic in Cagayan Valley Region, Philippines

Emer T. Quezon — Tue, 23 Feb 2021 19:26:02 +0100

In highway construction projects, labor-oriented work is an integral part of the management process, requiring analysis of factors affecting labor productivity during the Covid-19 pandemic. This research identified 53 influential factors affecting construction labor productivity at selected cities and towns in Cagayan Valley Region, Philippines. Due to the pandemic, the construction industries incurred substantial profit losses. More so, the construction workers are too much affected because of the Enhance Community Quarantine (ECQ) imposed by the local government. Results indicated there was laxity on the Covid-19 protocols. No health worker in the project site ranked the highest in the health & safety factor group with an RII of 0.97 and ranked 1st among 53 factors on the different groups. Besides, no safety engineer was assigned to the projects and ranked 2nd with an RII of 0.93. Among the 7 groups of factors, the health and safety group ranked 1st with 0.81, followed by the schedule compression group with an RII of 0.78. Hence, these two groups of factors have a strong relationship, as evidenced by the number of workers reduced. It was learned that the contractors’ strategy was to increase the number of working days to cope with their schedules. Hypothesis testing supported that there are various significant factors influencing labor productivity loss during the Covid-19 pandemic, as suggested by more than 50% of the respondents.

Investigation on the performance of ‘Fino’ materials to stabilize expansive soil: A case study in Yeka Sub-City, Addis Ababa, Ethiopia

Emer T. Quezon — Tue, 23 Feb 2021 18:48:12 +0100

Expansive soil swells when it is wet, and it will shrink when it dries. Due to this behavior of the soil, the strength and other properties of soil are inferior. To improve its properties, it is necessary to stabilize the soil with different stabilizers. Soil stabilization is a process to treat the soil to maintain, alter, or improve expansive soil performance. In this study, the potential of 'Fino' as stabilizing additive to expansive soil was investigated for the improving engineering properties of expansive soil to be used as subgrade material. The evaluation involved the determination of the Free Swell test, CBR test, Atterberg's limits, and the Proctor test of expansive soil in its natural state as well as when mixed with varying proportions of 'Fino.' The practices were performed on six proportions 5%, 10%, 15%, 20%, 25% and 30 % with expansive soil. The research result indicated a considerable reduction in Swelling, and the Maximum dry Density of soil was improved. Optimum moisture content decreased in increasing 'Fino.' At 30% of 'Fino,' the CBR values of expansive soil increased from 1.06% to 5.94%, Liquid Limit decreased from 95.2% to 29.4%, plasticity index decreased from 57.24% to 17.82% and the degree of expansion of the natural subgrade soil has reduced from 'very high to medium.' Hence, it is concluded that the 'Fino' at 30% has shown significant improvement in the expansive soil's engineering properties meeting the ERA and AASHTO Standard specifications requirements for road subgrade material.

PAVEMENT MANAGEMENT SYSTEMS: PAST, PRESENT, AND FUTURE

Benjamin Colucci — Fri, 19 Feb 2021 16:19:23 +0100

Pavement management is a decision-making process of vital importance at the international level for the preservation of road infrastructure. The planning, programming, and execution of maintenance and rehabilitation activities to preserve the road infrastructure at an adequate level of service requires a large investment of resources. The availability of these resources, including budgetary constraints, and the progressive deterioration of the pavements due to the action of cumulative traffic loads and environmental factors create a complex problem to be solved during the management process. The purpose of pavement management practices is to find the best strategy to provide the desired level of service. From a broader perspective, pavement management covers all phases of planning, programming, analysis, design, construction, and research. A Pavement Management System (PMS) is a tool that helps agencies make cost-effective decisions about maintenance and rehabilitation policies. PMPs allow evaluating alternative strategies and predicting the impact of maintenance and rehabilitation interventions on the future performance of the pavement network. This technical article describes the evolution of pavement management systems in an effort to face the great challenge of preserving road infrastructure efficiently and sustainable to provide an adequate level of service to present and future users.

RISE-UP: AN INTERDISCIPLINARY LEARNING TOOL TO GENERATE SUSTAINABLE AND RESILIENT INFRASTRUCTURE

Benjamin Colucci — Thu, 18 Feb 2021 21:35:59 +0100

The damage caused to Puerto Rico's infrastructure by Hurricane María in 2017 and the seismic sequence in 2020 provided evidence that, after a natural disaster, the collaboration of different disciplines is necessary to rebuild the damaged infrastructure using new paradigms. To develop a new generation of engineering and architecture professionals who work in an integrated way to face the challenges caused by natural events, the Resilient Infrastructure and Sustainability Education - Undergraduate Program (RISE-UP) was created. The program is structured using a collaborative platform between three campuses of the University of Puerto Rico system and is based on an interdisciplinary approach using Project-Based Learning (PBL). RISE-UP consists of four courses that are part of a minor degree that is complemented by internship and undergraduate research opportunities. The courses are taken sequentially in a process that starts with the presentation of basic content and techniques, to the application of that knowledge in an integrated design project. To date, a total of 64 students have entered the program, divided into two cohorts according to their admission into the program. Students in both cohorts reflect the diversity that the project seeks in terms of specialty area, campus, and gender. The results of the student evaluations indicate that 100% of the students find the PBL methodology "valuable" or "very valuable" to understand the importance of a sustainable and resilient infrastructure, putting into practice the concepts learned. This program serves as an example of the benefits of information technology integrations to allow students from different campuses to work together toward a
common goal.

EVALUATION OF MONTHLY RAINFALL CALCULATED WITH TRMM FOR METEOROLOGICAL DROUGHT STUDIES

Benjamin Colucci — Thu, 18 Feb 2021 19:33:41 +0100

Precipitation is considered the main variable for the evaluation of meteorological drought in a basin. Droughts are phenomena of different spatial scale, so that is convenient to have simultaneous rainfall records in time and in different locations, in order to analyze their evolution in space, depending on the size and the variability of the characteristics in the basin. In Argentina, specifically in the central region, the availability of information on the spatial variability of rainfall is not usual, so drought studies in this region are limited. Due to this it is convenient to validate the rainfall information obtained through satellite missions. The present work evaluates the validity and applicability of monthly rainfall data estimated through TRMM in ten stations in the basin of the Carcarañá River in the central region of Argentina and its subsequent application to studies on meteorological droughts through a representative index (SPI). Statistical parameters such as the concordance coefficient, the correlation coefficient and the bias were used for this analysis. There was a significant variation of the parameters with respect to the height. Was observed better coefficients in stations located in plain compared with stations located in mountainous areas.

A FLUTTER-BASED NON-CONVENTIONAL CONCEPT FOR ENERGY HARVESTING

Benjamin Colucci — Thu, 18 Feb 2021 19:09:35 +0100

Energy harvesting has currently taken a central role due to its application to feed low power devices, such as wireless sensors, radio-frequency transceivers, charging devices and cameras. Among other alternatives, wind energy harvesting based on aeroelastic phenomena plays a pivotal role in providing sufficient power for extended operation of such devices with little or no battery replacement. In this article, a concept that explores the possibility of harvesting wind energy using an array of harvesting devices is presented. Each device is built as a long span multifunctional wing that exhibits oscillatory motions under the action of the wind. The efficiency of these systems depends on inherently non-linear phenomena, as well as on the aerodynamic synergy between the harvesters, and between them and their wakes. In addition, a preliminary study of the feasibility of the concept is conducted through co-simulation techniques that allow one to investigate the fluid-structure interaction. The results of this effort are encouraging since they highlight the potential not only of the proposed concept but also of the combination of these new technologies with aeroelastic analysis and design methods to create a new generation of power harvesters.

USE OF THE ARTIFICIAL INTELLIGENCE FOR DRIVERS BEHAVIOR ANALYSIS AND VEHICULAR CRASHES GENERATION

Benjamin Colucci — Thu, 18 Feb 2021 18:48:02 +0100

This research is the result of the analysis of drivers´ behavior in a controlled scenario, using a driving simulator, in which, by measuring brain waves, the degree of concentration was (measured when driving and through the use of networks neuronal and artificial intelligence, a model of behavior of drivers was proposed to be subjected to a distracting effect while driving, which allows analyzing the most relevant factors that are reflected in errors and bad practices at the time of driving. In this research it was determined a population sample of men and woman whose ages oscillate between 16 to 90 years, from a universe obtained from a database of fatalities for 7 years.
A driving simulator was built, and it was using a software for the simulation that allows different driving scenarios. Finally, risk behaviors were classified to be a factor of distraction.

Introduction and overview of the prodPhD project

Julio García-Espinosa — Thu, 18 Feb 2021 11:27:02 +0100

The main objective of the prodPhD project is to implement innovative social network-based methodologies for teaching and learning entrepreneurship in PhD programmes. The multidisciplinary teaching and learning methodologies to be developed will allow introducing entrepreneurship education in any PhD programme of a higher education institution, providing students with the knowledge, skills and motivation to engage in entrepreneurial activities. The methodology will be conceived to develop experiential knowledge, involving academics, entrepreneurship experts and mentors in its development and implementation, by taking advantage of the use of customized collaborative social network tools. Besides, the exchange of experience, competences and approaches facilitated by social networking will allow crowdsourcing new ideas, improving training methodologies and stimulating entrepreneurial skills of academics.

INNOVATIVE RESEARCH THAT CONTRIBUTES TO SAFETY, SUSTAINABILITY AND RESILIENCE IN TRANSPORTATION SYSTEMS

Benjamin Colucci — Thu, 18 Feb 2021 01:06:23 +0100

Transportation infrastructure systems are vital for the effective, efficient, safe, and sustainable movement of people and goods, and promote the economic development of cities and countries for present and future generations. This article presents pertinent statistics related to mobility, safety, accessibility, equity, reliability, and resilience of transportation systems in the United States (U.S.) and internationally, and present some of the present and future challenges. Safety, congestion, and the human factor are emphasized in combination with innovative ideas and research-based remedial measures at the State and Federal level to mitigate congestion and improve safety for all users. Innovative ideas include the U.S. Federal Highway Administration's Every Day Counts program initiatives, findings from University Transportation Centers (UTC) SAFER-SIM ,and the National Institute for Congestion Reduction (NICR), and the use of driving simulators, virtual reality, unmanned aerial systems and alternative modes of transport such as e-scooters, and the successful management of knowledge transfer of these innovative initiatives at in person seminars and webinars through the Puerto Rico Transportation Technology Transfer Center.

CLASSICAL STRESS ANALYSIS OF A FUSE PLATE THAT FAILED DURING HURRICANE MARÍA IN PUERTO RICO

Benjamin Colucci — Wed, 17 Feb 2021 23:50:18 +0100

A large number of breakaway-type highway signs toppled over during hurricane María in Puerto Rico. The cause was the unintended rupture of the fuse plates, a key component of the breakaway system. The design of fuse plates is unusual because two opposing constraints must be precisely balanced: 1. they must be weak enough to rupture during collision of an errant vehicle, thus minimizing injuries to passengers and damage to the vehicle, but 2. strong enough to resist wind loads. These uncommon constraints attracted the interest of the authors. The following question guided the research: Could classical stress analysis, in conjunction with established failure theories, predict the failure of an actual fuse plate that fractured during hurricane María? This investigation fills a gap in the literature by examining a more refined classical model of the stresses than previously considered. A wind gust speed of 155 mph at the top of the sign was assumed. The yield and ultimate strengths were obtained experimentally with one tensile specimen machined from a failed fuse plate. The classical stress analysis, in conjunction with the von Mises yield failure criterion, accurately predicted yielding of the fuse plate; however, higher wind speeds would have been required to reach fracture. It was concluded that the simplified model available in the literature is adequate to predict yielding. Its error was less than 1% when compared to the more refined model developed in this study.

LANDSLIDE SCIENCE IN PUERTO RICO: PAST, PRESENT, AND FUTURE

Benjamin Colucci — Wed, 17 Feb 2021 23:38:17 +0100

This article presents an overview of landslide investigation in Puerto Rico from the time of Spanish control until the present. In addition, a projection for future developments is offered. The island’s tectonic and geographic situation combined with a history of intense agriculture practices yield a predisposition of landslide hazard. Mass wasting manifests itself in several modalities with shallow soil failures being most common and deep bedrock slides being most destructive. Movements can be provoked by seismic activity but are regularly triggered by high-intensity rainfall events associated with tropical cyclone systems. Advances in landslides science made during the latter 20^th century were made possible by earlier topographic and geologic mapping efforts by the United States Geologic Survey. In the 21^st century, instrumentation and monitoring endeavors have been made more effective with the use of emerging technologies. In the near future, advanced real time systems and forecasting programs are possible, and the continued investigation of landslides as principal agents of erosion will lead to a more focused understanding of surficial processes over geologic time. In a landscape faced with natural disasters, it is necessary to meet these phenomena with an adequate level of commitment in order to mold a more resilient society.

NEW BUILDING CODES 2018 AND EDUCATION TO IMPROVE RESILIENCE OF COASTAL INFRASTRUCTURE IN PUERTO RICO

Benjamin Colucci — Tue, 16 Feb 2021 20:41:41 +0100

The archipelago of Puerto Rico is prone to multiple hazards due to its very particular location in the Caribbean and its frequent exposure to extreme natural events. Since 2017, the Island has faced hurricanes, tropical storms, a sequence of earthquakes, drought, and various flood events caused by extreme cyclonic rainfall that have caused damage to coastal infrastructure. To support Puerto Rico's recovery after Hurricane María, numerous projects were developed and implemented. Many of these projects were funded through FEMA and acted as key catalysts for response, recovery, and public policy. FEMA's Mitigation Assessment Team, also known as MAT, developed recommendations to rebuild a more resistant infrastructure. Among the key recommendations is the adoption of the Puerto Rico Building Code of 2018. To facilitate the transfer of knowledge to the community in general (students, teachers, professionals, first responders and the workforce), the Center for Coastal Resilience (CRC) established two educational programs: the first is a continuing education program open to the general public; and the second is a formal program for university students that includes courses leading to degrees, projects, research, and internships. Adoption of the latest building codes and FEMA recommendations provide the tools for a resilient coastal infrastructure. The continuing education program has impacted 2,311 community members to date, increasing their knowledge and understanding of the different stages of prevention, preparedness, response, recovery, and risk mitigation of coastal infrastructure.

FORENSIC EVALUATION AND LESSONS LEARNED OF PRESTRESSED CONCRETE POLE FAILURES IN PUERTO RICO DURING HURRICANE MARIA

Benjamin Colucci — Tue, 16 Feb 2021 20:09:10 +0100

This article summarizes the lessons learned from the evaluation of failed concrete utility poles in Puerto Rico as a consequence of Hurricane Maria. Teams were deployed between October 3^rd to 11^th 2017, to cover the west, northwest, south, and east of the island. The evaluation presents sample cases of the failed poles around the island but does not attempt to conduct an inventory. The Puerto Rico building code was being updated based on changes in the International Building Code and the effects of Hurricane Georges. However, many poles made from previous designs are still in service, and many of them failed as a consequence of design deficiencies and improper construction practices. Poles manufactured under the updated codes failed mostly due to foundation issues or structural overload from nearby vegetation impact and the failure of in-line poles, especially wood poles and pre-Georges concrete poles.

THE ANALYSIS OF STRUCTURAL FAILURES IN TRANSPORTATION INFRASTRUCTURE USED TO ESTIMATE WIND SPEEDS OF HURRICANE MARIA IN PUERTO RICO

Benjamin Colucci — Tue, 16 Feb 2021 19:32:04 +0100

Hurricane Maria made landfall in Puerto Rico on September 20, 2017. Its strong winds and rainfall intensity were responsible for significant damages to the infrastructure and to all types of construction in Puerto Rico. The hurricane and its effects have been intensively studied over the past three years. These studies include estimates of the gust speeds that the hurricane produced. These estimates appear to be lower than those expected for a hurricane of Maria’s category. The present study sets out to contribute to these estimates by analyzing the failures of elements of the transportation infrastructure, obtaining as a result that the gust speeds required to produce the analyzed failures were significantly higher than those of previous studies. This findings suggests that a review of the estimated gust speeds for Hurricane María is pertinent, which would make it possible to better interpret its effects. In turn, this could have an impact on the definition of relevant design speeds for Puerto Rico to design resilient systems under a future update of the building codes of the island.

IMPROVEMENTS TO THE STRONG MOTION SEISMIC NETWORK FOLLOWING HURRICANES IRMA AND MARIA AND THE SEISMIC SEQUENCE

Benjamin Colucci — Tue, 16 Feb 2021 19:03:31 +0100

The Puerto Rico Strong Motion Program (PRSMP) has 114 strong motion stations and 21 seismically instrumented structures in five (5) countries. This paper explains how the PRSMP has been able to recover from the detrimental effects of Hurricane María to become a more robust, strong motion network in terms of instrumentation with 100% of the data loggers with recent technology, in terms of energy with 48/90 (53%) of the free field stations in the Island with photovoltaic systems, and in terms of communication with 51/90 (57%) transmitting its data real time and developing two data centers. In addition, the southwest Seismic Sequence, with its main event on January 7, 2020, has allowed the increment of strong motion stations and the improvement of its communication in the region that covers from Ponce to Mayagüez.

BEHAVIOR OF TYPICAL INDUSTRIAL BUILDINGS USING PREFABRICATED DOUBLE-T-TYPE ROOFS DURING EARTHQUAKES IN JANUARY AND MAY 2020 IN PUERTO RICO

Benjamin Colucci — Tue, 16 Feb 2021 16:34:02 +0100

The recent earthquakes that occurred in January and May 2020 in Puerto Rico have revealed the vulnerability of industrial buildings that use prestressed concrete double-T beams, due to poor connections and insufficient support lengths between the double-T beams and the supporting beams that are prefabricated. These beams sometimes are supported by concrete brackets representing an additional risk. In the supports, displacements have been observed in the joints causing diagonal cracks and angle separation related to the horizontal transfer between the joists and supporting beams. In these supports there is a lack of capacity due to shear and poor ductility due to the connection made with metal plates embedded in the web of the joists and angles located along the edge of the prefabricated beams.

A Technology to (re-)Connect Optical Fibres Embedded in Composite Structures

Scipedia content — Tue, 16 Feb 2021 09:26:37 +0100

Optical fibre Bragg grating (FBG) sensors are commonly used for structural health monitoring in composite materials, since their small dimensions, high sensitivity and multiplexing capacity are a good match with the structures to be monitored. We present a method for making a low-loss connection to an FBG optical fibre sensor that is integrated in a fibre reinforced composite structure. The method allows to both manufacture composite structure without taking special precautions to prevent damage to the connecting fibre and (if needed) to repair the connecting fibre, while optimizing the optical connection efficiency even if both fibres have dissimilar mode field diameters.

Multifunctional Fuselage Demonstrator: Thermoplastic Composite Skin Manufacturing Developments

Scipedia content — Tue, 16 Feb 2021 09:26:13 +0100

Within Clean Sky 2 the design and manufacturing of the fuselage of new single aisle aircraft is investigated through a large, multi-functional fuselage demonstrator, see Figure 1. The main objectives of this demonstrator are to enable high production rates with a minimum of 60 aircraft per month and to reduce structural weight and recurring cost. The envisaged demonstrator shall validate high potential multi-functional combinations of airframe structures, systems, cargo and cabin technology concepts for the next generation fuselage and cabin, using advanced materials and innovative design principles. One of the key innovations for the multi-functional fuselage demonstrator is the modular assembly of pre-equipped sub-assemblies, see reference [1] and [4]. To make a step in the design and manufacturing of such integrated multi-disciplinary fuselage sub-assemblies, including components of structures, systems, cabin and cargo, advanced materials and manufacturing methods are required. Thermoplastic composites and their highly automated fibre placement production techniques and advanced joining methods, offer the flexibility and efficiency that is needed for the production of much more pre-equipped sub-assemblies to enable the modular assembly process for the future aircraft production supply chain.

Structural Assessment of FML Aerostructures with Integrated Electromagnetic Features

Scipedia content — Tue, 16 Feb 2021 09:25:50 +0100

A substantial contribution to reduce the aerodynamic drag and consequent CO₂ and NO_x emissions is to integrate communication antennas in the aircraft structure. This paper presents a GLARE fuselage panel design for an integrated VHF slot antenna and discusses the results of a mechanical experimental campaign on a structural element level, in quasi-static tensile conditions. The tested specimens showed small variability in terms of stiffness and strength (typical for GLARE), little dependence on the ambient conditions, damage presence, and layup configurations and good agreement with early numerical simulations. In addition, stiffness and strength predictions, based on empirically found design values seem to correlate well with the found test values

VHF Communication Antenna Integrated into an Aircraft Winglet

Scipedia content — Tue, 16 Feb 2021 09:25:34 +0100

The article is discussing the final design of a VHF communication antenna integrated in a composite winglet of the EV-55 small transport aircraft. The antenna is designed to operate in the VHF band reserved for civil aviation, 117.975 – 137 MHz with optimal VSWR below 2.5. Compared with a standard vertically polarized monopole antenna, the radiation pattern in the horizontal plane shall not be down more than 6 dB and vary more than 6 dB [2].

Experimental Analysis of the ACASIAS Active Lining Panel

Scipedia content — Tue, 16 Feb 2021 09:25:12 +0100

The participants of the EU-project ACASIAS develop advanced concepts for aerostructures with multifunctional capabilities. Within work package 3 an active system for noise reduction is integrated into a curved lining panel. The objective is the reduction of the interior sound pressure level by increasing the transmission loss of the lining panel. The application scope includes current propeller driven aircraft and future aircraft with counter-rotating open rotor (CROR) engines. The drawback of these CO₂-efficient engines is their high sound emission in the frequency band up to 500 Hz. Active noise reduction systems are able to achieve performance in this frequency band while passive sound insulation materials fall behind. Thus, active systems are the key technology to avoid unacceptably high noise levels for passengers. During the last period of the project the main experiments are conducted. The active lining with its dimensions of 1300 × 1690 mm² (W × H) is mounted in a setup in the acoustic transmission loss test facility of the DLR. Several tests in different categories are run to characterize the vibration and sound transmission behavior of the lining. In this paper the active lining and its components are briefly introduced and the results of the modal and the thermal testing are presented.

Noise Reduction Results of the ACASIAS Active Lining Panel

Scipedia content — Tue, 16 Feb 2021 09:24:50 +0100

Advanced concepts for aero-structures with multifunctional capabilities are investigated within the EU-project ACASIAS. In work package 3 of ACASIAS, components of an active noise reduction system are structurally integrated into a curved sandwich panel by means of 3D printed inserts. This so-called smart lining is intended for application in aircraft as a modular and lightweight interior noise treatment in propeller-driven aircraft. The broad application scenario of smart linings ranges from retro-fitting of current regional aircraft such as ATR 42, ATR 72, DHC-8 Q400 to the application in new short-range aircraft with energy efficient counter rotating open rotor (CROR) engines or with distributed electric propellers. A key feature of the smart lining with integrated active components is its modularity, facilitating a flexible application in the aircraft cabin. This requires a fully self-contained sensing mechanism based on structurally integrated accelerometers. Using the normal surface vibration data from the integrated sensors, the smart lining is able to predict the sound field in front of it. The so-called virtual microphone method with remote sensors and observer filter allows to get rid of real microphones and wiring in the aircraft cabin. This makes retro-fitting easier because it reduces wiring effort and costs which is beneficial for future aircraft as well. However, the use of virtual instead of real microphones might deteriorate the performance or even the stability of the active noise reduction system because it relies on accurate plant models. Laboratory experiments in a sound transmission loss facility are conducted to assess the behavior of the smart lining with virtual microphones and compare it to a smart lining with real microphones. The sensitivity of the smart lining to environmental changes and the noise reduction performance and control system stability are investigated in this study.

System Development of Transmitting Conformal SATCOM Array Antenna Structures(CSAAS)

Scipedia content — Tue, 16 Feb 2021 09:24:32 +0100

This study presents the development results of Conformal SATCOM Array Antenna Structure(CSAAS) for transmitting. Tile Type antenna with 8x8 antenna element array has been developed instead of reflector antenna. 8x8 tile antennas are arrayed on the curved surface with one directional curvature to simulate aircraft skin configuration. Housing has the grid structure to minimize out-of-plane deformation that affects the antenna performances. Tile antennas are attached to the surfaces between grids. Radome is designed as an A-sandwich type to carry some distributed skin load and glass epoxy material with lowest dielectric constant and loss tangent was used for the best electromagnetic performance. One tile antenna is designed with a separate data control and power connection for vertical and horizontal polarization. The static structural strength of the housing and impact strength of the radome were verified by the analysis and tests. Beam pattern test, beam control test and beam steering test are performed in an anechoic chamber for the transmitting CSAAS. The results of structural and electromagnetic tests showed that the design objects met the goal successfully.

Influence of the Angle between Adherends on Ultrasonic Welding of Thermoplastic Composites

Scipedia content — Tue, 16 Feb 2021 09:24:14 +0100

Research on ultrasonic welding of composites has focused mostly on studying parameters that are inputs for the process or material-related parameters, but almost no attention has been given on the effect of manufacturing tolerances. In this work, we investigated how an angle between adherends impacts the welding process and the weld quality. By increasing the angle between top and bottom adherends, it was found that the duration of the process increased while the power consumed, the weld uniformity and the weld strength decreased. However, by increasing the clamping distance, which increased the compliance of the adherends and hence their ability to deform under the applied welding force, the effect of the misalignment on both the welding process and weld quality could be substantially reduced.

Development of a Numerical Framework for Virtual Testing to Support Design of a Next Generation Thermoplastic Multifunctional Fuselage

Scipedia content — Tue, 16 Feb 2021 09:23:25 +0100

This work summarizes the recent developments of a numerical framework to predict the mechanical behaviour of thermoplastic composites. It supports the design of a next generation thermoplastic multi-functional fuselage which uses advanced joining techniques such as thermoplastic welding to reduce both weight and cost by limiting the amount of mechanical fasteners required. At the lower end of the testing pyramid the framework is able to accurately predict typical preliminary design allowables such as laminate, open-hole and welded joints strength through a high-fidelity modelling approach. This information is then passed on to the structural level in a validated building-block approach to efficiently virtual test the compression strength of fuselage panels during post-buckling while also taking into account the influence of damages at the skin-stiffener interface.

GNSS Antenna Integrated into a Classical Fibre Metal Laminate Fuselage Panel

Scipedia content — Tue, 16 Feb 2021 09:22:01 +0100

Fibre Metal Laminate materials, like Glass Laminate Aluminum Reinforced Epoxy (GLARE), provide a unique opportunity to integrate patch antennas directly into the fuselage of aircraft. This integration will contribute to the reduction of carbon emissions of aircraft due to the reduction of aerodynamic drag. This paper discusses the integration of a double patch GNSS antenna directly into a classical Fiber Metal Laminate. A demonstrator of the antenna was manufactured and measured. The antenna has a flush finish on the outside of the fuselage. The preliminary results of these measurements show promising antenna performance, but more measurements are required to fully characterize this integrated antenna.

RF Analyses of Integrated Ku-band Antenna

Scipedia content — Tue, 16 Feb 2021 09:15:36 +0100

In the ACASIAS project an integrated antenna for Ku-band satellite communication has been developed. The design of this integrated antenna has to meet structural, electromagnetic and thermal requirements. This paper addresses the electromagnetic performance of the antenna both by design and by measurement. For the design of the antenna, the electromagnetic interaction of the antenna with the conducting Carbon Fibre Reinforced Plastic (CFRP) ribs of the orthogrid and the interaction with the Glass Fibre Reinforced Plastic (GFRP) skin of the panel have been analysed. In addition, the influence of potential lightning diverters on the antenna performance has been analysed. The radiation pattern of a single antenna tile and the radiation pattern of an antenna tile integrated in the orthogrid fuselage panel were measured. The results of the antenna measurements are compared with the results of the simulations carried out for the design of the antenna.

Structural Analyses of GLARE-GFRP Transition for Integrated VHF Antenna on a Fuselage Panel

Scipedia content — Tue, 16 Feb 2021 09:01:29 +0100

The objective of this paper is to describe the numerical simulation of the transition zones in the multifunctional fuselage panel design to integrate a VHF (Very High Frequency) antenna. The panel is made of GLARE (Glass Laminate Aluminium Reinforced Epoxy) with a central window of GFRP (Glass Fibre Reinforced Polymer). The structural analyses of the transition GLARE/GFRP is presented along with its experimental validation. The numerical simulations showed a very high level of correlation with the experimental tests, both in the longitudinal load vs displacement curves and deformations captured with strain gauges and DIC (Digital Image Correlations).

VHF Antenna Integrated into a Classical Fibre Metal Laminate Fuselage Panel

Scipedia content — Thu, 11 Feb 2021 09:46:02 +0100

Replacement of protruding antennas by integrated alternatives will reduce the energy consumption and NO_x and CO₂ emissions of an aircraft. This paper proposes and integrated VHF cavity backed slot antenna that is suitable to replace blade antennas. To reduce the size of the cavity a parallel plate resonator is used. The slot is integrated into a fibre metal laminate fuselage panel. A bookleafing principle is used to reinforce the panel at the position of the slot, making sure the material quality is not reduced. Measurement results of a demonstrator antenna show the feasibility of the proposed antenna. Moreover, the paper discusses several electromagnetic and structural design trade-offs for this integrated antenna.

Modernization of programmable automatons, an analysis in the primary selection

AutanaBooks — Thu, 11 Feb 2021 07:08:15 +0100

The analysis of a research work developed in the company C.V.G CARBONORCA of Venezuela is presented, which has two gas purification plants for the cooking area, designed to purify the gas that comes from the cooking ovens. Each plant is made up of solenoid valves, pneumatic valves, transmitters, process mimic panel and a supervisory system. All these elements are governed by a SIEMENS S5-115U PLC which is in a state of obsolescence, which is why the replacement of these automata by ALLEN BRADLEY ContolLogix automata was designed, in order to guarantee continuity in operations in plant. The research was done with a descriptive design of the field experimental type. A code for each gas treatment plant was obtained in RSLOGIX 5000 v17.00.00 and the update of the database of the supervisory system. The operation of the program was also verified through a simulation of the plant in a supervisory system, the deployment of which was designed for this purpose.

PID controllers analysis For a second order floor using neuronal networks

AutanaBooks — Thu, 11 Feb 2021 07:08:12 +0100

Second order systems are those that respond to a second order differential equation. The study of a second order system is proposed, given by an RC electric circuit. The transfer equation was determined and the transient response was analyzed using the method of the Geometric Place of the Roots, likewise the coefficients of the PID controller were determined. From the response of the PID controller, a backpropagation neural network was created and trained to later replace the classic PID controller. In this work, the analysis of a PID controller case study is carried out where an artificial neural network has been implemented to evaluate its response. It is observed that the results are acceptable and with a good transient response.

Social responsibility in Latin America: A perspective from Industrial Engineering

AutanaBooks — Thu, 11 Feb 2021 07:08:10 +0100

This research work will address business issues and related to social responsibility. Likewise, a comparison will be made between continents to know the different aspects according to the location of the companies and their participants. In the same way, an analysis will be approached mentioning different definitions regarding this topic and the role of an industrial engineer in these aspects. After arguing and overcoming all the issues about socially responsible companies, an example will be presented that meets all the previously established points. Before concluding, from the social point of view, possible scenarios in which the implementation of corporate social responsibility could be feasible will be illustrated and finally the factors that influence organizations or companies to fail to comply with social responsibility will be established.

Neural techniques for transformer insulator analysis

AutanaBooks — Thu, 11 Feb 2021 07:08:06 +0100

This article presents the Analysis of Partial Discharges using Neural Techniques. Rotating machines used in industry tend to have insulation failures caused by lack of maintenance and ignorance of their status. It is important to carry out periodic tests and continuous evaluations of the state of the insulation to guarantee the correct operation of the machines. One of the methods used to detect these faults is Partial Discharge. Which consist of small discharges produced in a portion of gas that is dissolved in the oil or dielectric that constitutes the insulation of electrical machines. In this research work, an analysis of two works developed around partial discharges is carried out, where artificial intelligence techniques have been implemented. The results showed a high effectiveness of neural networks to achieve the classification ofpartial discharges and contribute to the maintenance of high-power electrical equipment.

Effect of the decomposition of ammonia gas (NH3) on the swelling of iron oxides during reduction

AutanaBooks — Thu, 11 Feb 2021 07:08:03 +0100

The purpose of this work is to study the relation and the effect of nitrogen in the reducing gas mixture used in the isothermal reducibility testing of the iron oxide by planning and carried out using ammonia gas so that its decomposition produces 15% H2 and N2 gases. Ammonia gas also 6% by volume was added to a gas flow containing 28% H2 y 68% N2 by weight so that obtain a final gas composition of 30% H2 and &0% N2. This reinterpretation of the test data allowing the comparison of reducibility test reducibility in such a way to compare the nitrogen effect on swelling of iron oxides undergoing reduction. The comparison was made based on the theoretical estimation of nitrogen absorption, the fresh metallic iron formation during the hematite-magnetite-Wustite so produced and the abnormal volume increase of the considered samples. It was also possible to empirically relate and compare the studied effects of nitrogen content from different sources but gas such as solid carbon containing reducers such as coal.

International green market & socially responsible companies

AutanaBooks — Thu, 11 Feb 2021 06:29:02 +0100

This essay aims to emphasize the alternatives that are being taken globally to reduce the environmental impact of human activity. Key points and concepts will be developed regarding the international green market, socially responsible companies (SRC) and the relevance of these in modern society and economy. These concepts have been gaining strength in the last decade due to new consumers, who are more concerned and empathic with the environment and the community, and to companies that pursue to satisfy the needs of these consumers while being socially responsible while remaining profitable.

Robotic hand design with linear actuators based on Toronto development

AutanaBooks — Thu, 11 Feb 2021 06:20:12 +0100

In this work, the design of a robotic hand with 7 degrees of freedom is presented that allows greater flexibility, achieving the usual actions performed by a normal hand. The work consists of a prototype designed with linear actuators and myoelectric sensor, following the mechanism of the University of Toronto for the management of functional phalanges. The design, construction description, components and recommendations for the elaboration of a flexible and useful robotic hand for amputee patients with a residual limb for the socket are presented.

Impact on the video game industry during the COVID-19 pandemic

AutanaBooks — Thu, 11 Feb 2021 06:20:10 +0100

This work presents trends and comparisons that show a change in the consumption and production of video games in times of confinement due to the health emergency. The video game industry has modified its philosophy and adapted its products to the new requirements and trends of consumers who see in this activity a way to appease the psychological and social impact due to quarantine and isolation. There is evidence of a 65% increase in the use of online video games, which has broken a world record. Products that have new aspects and considerations never before proposed by this great industry have been developed and offered, such as thematic games related to the COVID-19 pandemic.

Criteria for the design of an educational robotics platform

AutanaBooks — Thu, 11 Feb 2021 06:20:07 +0100

This document explains the criteria, considerations and formulations used for the design of the main components of a mobile platform with a robotic arm. This type of robot is one of the most used in the educational field, it facilitates learning and allows the incorporation of control strategies for navigation. Aspects of resistance of materials useful for branches of engineering that lack bases on mechanics are raised.

Comparative study on the un test n`5 application on cargoes that emit flammable gases similar to dri c that requires ventilation

AutanaBooks — Thu, 11 Feb 2021 06:20:03 +0100

This technical note summarizes a technical comparison of common testing procedures, as well as reviewed of the UN Test N` 5, for the assessment of the self-heating properties of cargoes and materials that has shown a clear trend on maritime fire and explosions events, as well as considering of external factors that can combine self-heating and emit flammable gases to conclude in an unlikely event affecting the security of crews and ships. A high understanding of the external factors effect on the cargo materials certainly will help the application of spontaneous reactions management actions (SRMA) on board of ships during the cargo sea passage. The intended comparison is based on laboratory, industry and field observations and data, whereas the among the external factors considered are, moisture content, stockpile procedure and aging, air velocities and moderate pressures internal and externally to the cargo material. The comparison results have shown that the self-heating and the flammable gas emissions has a common pattern when reacting with any oxygen available source, regardless the reactive material chemical composition.

NEAR FIELD EARTHQUAKES CHARACTERIZATION

Benjamin Colucci — Fri, 05 Feb 2021 20:24:52 +0100

Near field earthquakes are those that have their epicenter at less than 20 km with respect to the site of interest. These earthquakes have particular conditions that pose a high seismic threat and are not covered by the regional seismic hazard parameters established from regional studies. Some design codes require a specific assessment of this situation for structure design, but do not specify methods or references for this evaluation. This article presents a description of the characteristic conditions of near field seismic movement based on the analysis of real records. It shows how near field earthquakes have a coherent pattern of long-period, high-intensity movements that originate from the rupture displacement in the source. Because of the long-period movements they significantly affect the coseismic displacements which can become quite large. This effect is attenuated at distances larger than 20 km. This information is useful in characterizing the seismic threat in cases where there are shallow seismic sources near the site of interest.

EARTHQUAKE EXPERIENCE IN PUERTO RICO AND THE CARIBBEAN: LESSONS AND WHAT WE HAVE LEARN FROM THEM IN THE LAST TWO DECADES

Benjamin Colucci — Fri, 05 Feb 2021 20:08:20 +0100

The Commonwealth of Puerto Rico, an unincorporated territory of the United States, and the smallest island of the Greater Antilles, is approximately 200 km by 60 km; it is also the island with the highest population densities within the Caribbean region. Several historical earthquakes have caused extensive damage to Puerto Rico and have generated Tsunami. There is a great concern to many geophysicists who believe that the subduction zone (Puerto Rico Trench) may be due for a major event because it has not ruptured in over 200 years. This research provides a description of the Peak Ground Acceleration (PGA) and instrumental Intensity (IMMI) distribution of significant moderate magnitude (5.0≤M≤6.4) earthquakes, the temporal-spatial patterns of the regional and local seismicity, within Puerto Rico Island (PRI) occurred during the last two decades, the lessons we have learned from them, and their association with the known mapped faults and the historical earthquakes (M≥7.0), as well as to the un-known faults and the earthquake epicentral clusters within the PRI and Caribbean region. In addition, the tectonic frame and faults of the region and the Puerto Rico Strong Motion Program (PRSMP) seismic network instruments coverage and distribution is provided. Finally, it was found the most recent Puerto Rico Seismic Hazard Map (2003), contained in the current building code, does not take into account the multiple partially studied active seismic faults that were found within the Island and that at least one of them could generate magnitude 7.5 earthquakes. Update the PRI Seismic Hazard Map considering the new identified active faults and the new findings of the seismic studies and the local site effects is plenty justified.

INTERACTION AMONG SCIENTISTS, ENGINEERS AND THE AFFECTED COMMUNITIES ABOUT THE IMPACT OF EARTHQUAKES AND TSUNAMIS IN PUERTO RICO

Benjamin Colucci — Fri, 05 Feb 2021 19:33:40 +0100

The M6.4 earthquake in January 7, 2020 in the Southwest of Puerto Rico caused damage to housing and buildings, and generated anxiety among the residents. The aftershocks were very active in the following months and are still felt, although with less intensity and frequency. A group of researchers from University of Puerto Rico at Mayagüez and the National Oceanic and Atmospheric Administration (NOAA) took over the task of going to the communities that requested their visit to deliver informative talks about the events. These included information on the geology of the zone, details on the ground movements, Tsunami threats, the effects on the structures, what to expect in future events, and how to react to the strong ground movement. This article summarizes part of that group experience, including technical information about the earthquake and answers to some of the most commonly asked questions from the provided lectures.

EVALUATING RISK FROM A HOLISTIC PERSPECTIVE TO IMPROVE RESILIENCE: A SUBNATIONAL LEVEL EVALUATION IN COLOMBIA

Benjamin Colucci — Fri, 05 Feb 2021 18:12:50 +0100

Disaster risk is not only associated with the occurrence of intense hazard events but also with the vulnerability conditions that favour or facilitate disasters when such events occur. Vulnerability is closely linked to social processes and governance weaknesses in disaster-prone areas and is usually related to a set of factors of fragility, susceptibility, and lack of resilience of the exposed human settlements. The holistic risk assessment aims to reflect risk from a comprehensive perspective by using, in one hand, the physical risk or potential physical damage directly linked to the occurrence of hazard events and, on the other hand by capturing how underlying risk drivers or amplifiers –social, economic, environmental factors, non-hazard dependent elements, may worsen the current existing physical risk conditions in terms of lack of capacity to anticipate or resist, or to respond and recover from adverse impacts. This article presents the results of the holistic evaluation obtained at subnational level in Colombia in the framework of the Risk Atlas of Colombia of the National Unit for Disaster Risk Management, UNGRD. The evaluation was performed using the probabilistic physical risk results obtained in the multi-hazard risk assessment and 16 socio-economic indicators available for 1,123 municipalities of Colombia. These results are useful to identify risk drivers that are associated not only to the physical vulnerability of the buildings and infrastructure but also to social issues that should be examined and tackled in a comprehensive way.

FLEET AND FUEL STRATEGIES FOR TRANSPORTATION RESILIENCE

Benjamin Colucci — Fri, 05 Feb 2021 16:36:16 +0100

The state of Florida, including the Tampa Bay region, is considered one of the most vulnerable areas in the United States to hurricanes and severe tropical weather. A particular vulnerability stems from the fact that Tampa Bay receives all of its petroleum—gasoline and diesel—through Port Tampa Bay, which can be impacted by hurricanes and tropical storms, as well as other disasters. If the port is unable to receive ships due to hurricane wind or storm surge, fuel cannot be delivered to the area, and transportation is impeded. One promising way to avoid this reduction in transportation functionality is to diversify the fuels used. This paper summarizes previous fuel challenges and vulnerabilities experienced by key Tampa Bay fleets after the area’s most recent tropical event—Hurricane Irma in 2017—in order to explore ways to improve the resilience of Tampa Bay to natural disasters. Some of these strategies include maintaining emergency fuel supply, prioritizing fuel use, developing innovative real-time resource sharing mechanisms, strategically placing the assets around the region to assist with the recovery, investing in backup generators, planning for redundancies in fuel supply networks, and diversifying fuel sources by incorporating alternative fuel vehicles into the fleet.

COLLAPSE OF THE ARECIBO OBSERVATORY IN PUERTO RICO: REFLECTIONS FROM A STRUCTURAL ENGINEERING PERSPECTIVE

Benjamin Colucci — Fri, 05 Feb 2021 15:04:58 +0100

The suspended platform of the Arecibo Observatory collapsed on December 1, 2020, after 57 years of illustrious service to the scientific community. This article reflects on the collapse from a structural engineering perspective. It explores issues that most likely contributed, including the cable terminations and their performance under loading, corrosion, fatigue, safety factors, the dynamic demands on the remaining cables when one of them suddenly snaps, and the dynamics of the suspended platform during its pendular swing. The article is based on publicly available reports from the news media, photographs, and published video recordings of the collapse sequence. These were expanded with relevant studies collected from the literature and with publicly available technical reports from structural engineering consultants that evaluated the structure during its final months. It is organized as a sequence of events, starting with the first cable failure on August 10, 2020, the second failure on November 6, 2020, and the final collapse. Despite the limitations, it is concluded that corrosion does not seem to have played a significant role, and that the failure of the first cable was most likely due to flaws during the fabrication of the cable/socket connection. These will be reviewed and updated once the forensic analyses of the failed elements are concluded and made public.

FIBRE4YARDS: Fibre Composite Manufacturing Technologies for the Automation and Modular Construction in Shipyards_20210128

Scipedia content — Wed, 03 Feb 2021 17:53:03 +0100

The main objective of FIBRE4YARDS project is to maintain European global leadership in ship building and ship maintenance, through implementation of the Shipyard 4.0 concept in which advanced and innovative FRP manufacturing technologies are successfully introduced.

This project has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement n°101006860.

A fully Lagrangian formulation for fluid-structure interaction between free-surface flows and multi-fracturing solids and structures

María Jesús Samper — Wed, 03 Feb 2021 16:15:49 +0100

It is well known that in civil engineering structures are designed so that
they remain, whenever possible, in an elastic regime and with their mechanical
properties intact. The truth is that in reality there are uncertainties
either in the execution of the work (geometric errors or material quality) or
during its subsequent use (loads not contemplated or its value has been
estimated incorrectly) that can lead to the collapse of the structure. This
is why the study of the failure of structures is inherently interesting and,
once is known, its design can be improved to be the less catastrophic as
possible or to dissipate the maximum energy before collapsing. Another
area of application of fracture mechanics is that of processes of which
interest lies in the breakage or cracking of a medium. Within the mining
engineering we can enumerate several processes of this nature, namely:
hydraulic fracture processes or fracking, blasting for tunnels, explosion of
slopes in open pit mines, among others. Equally relevant is the analysis of
structural failures due to natural disasters, such as large avenues or even
tsunamis impacting protection structures such as walls or dikes. In this
work numerous implementations and studies have been made in relation
to the mentioned processes.
That said, the objective of this work is to develop an advanced numerical
method capable of simulating multi-fracture processes in materials and
structures. The general approach of the proposed method can be seen in
various publications made by the author and directors of this work. This
methodology is meant to cover the maximum spectrum of engineering
applications possible. For this purpose, a coupled formulation of the Finite
Element Method (FEM) and the Discrete Element Method (DEM) is used,
which employs an isotropic damage constitutive model to simulate the
initial degradation of the material and, once the strength of the material
has been completely exhausted, those Finite Element (FE) are removed
from the FEM mesh and a set of Discrete Element (DE) are generated
at its nodes. In addition to ensure the conservation of the mass of the
system, these DE prevent the indentation between the fissure planes
thanks to the frictional repulsive forces calculated by the DEM, if any.
Additionally, in this work it has been studied how the proposed coupled
method named FEM-DEM together with the smoothing of stresses based on the super-convergent patch is able to obtain reasonably meshindependent
results but, as one can imagine, the crack width is directly
related to the size of the elements that have been removed. This favours
the inclusion of an adaptive remeshing technique that will refine the mesh
where it is required (according to the Hessian of a nodal indicator of interest)
thus improving the discretization quality of the crack obtained and
thereby optimizing the simulation cost. In this sense, the procedures for
mapping nodal and internal variables as well as the calculation of the
nodal variable of interest will be discussed.
As far as the studies of natural disasters are concerned, especially
those related to free-surface water flows such as tsunamis, one more
level of coupling between the aforementioned method FEM-DEM and one
Computational Fluid Dynamics (CFD) formulation commonly referred to as
Particle Finite Element Method (PFEM) has been implemented. With this
strong coupled formulation, many cases of wave impacts and fluid flows
have been simulated against solid structures such as walls and dikes,
among others.

Análisis térmico-mecánico de los segmentos de máquinas briqueteadoras en industrias siderúrgicas

AutanaBooks — Thu, 28 Jan 2021 00:14:04 +0100

Se realiza un análisis térmo-mecánico del comportamiento de los segmentos de los rodillos de las máquinas briqueteadoras por efecto del choque térmico y esfuerzos ejercidos en la pieza. Se pretende obtener las principales causas que generan este problema, mediante un análisis mecánico que permitió simular el comportamiento en presencia de varios gradientes térmicos. La finalidad del estudio es reducir costos de mantenimiento y la sustitución y reparación continua de segmentos, así como las pérdidas en toneladas de producción a causa de la falla que son de gran impacto para la industria. Esta investigación permite conocer en qué medida los parámetros operativos, tales como: temperatura del material, presión, torque, velocidad de los rodillos influyen en la vida útil de los segmentos de acuerdo a su material de fabricación y en función de estos se simulo el comportamiento durante el proceso de briqueteado.

Sistemas híbridos en diseño de distribución eléctrica con algoritmo genético

AutanaBooks — Thu, 28 Jan 2021 00:00:03 +0100

Se estudia la incorporación de sistemas híbridos basados en fuentes renovables para la optimización de sistemas de distribución eléctrica y planificación de estrategias de alimentación eléctrica usando algoritmos genéticos (AG). Se eligió una serie de características de sub estaciones eléctricas y mediante simulaciones, se obtuvieron datos para la optimización de la infraestructura existente, que brinde confiabilidad, seguridad, suministro económico y calidad de servicio. Se obtuvo un algoritmo con la configuración óptima de diversos componentes: paneles fotovoltaicos, baterías, generador AC, pila de combustible e inversor, que en el caso de la optimización mono-objetivo se logró la minimización de costos totales del sistema a lo largo de su vida útil. Se obtuvo la estrategia de control o combinación de variables de control más adecuada para minimizar los costos.

Metodología Seis Sigma en el Incremento de Producción de Spirulina.

AutanaBooks — Wed, 27 Jan 2021 23:29:03 +0100

En este trabajo se presentan resultados de mejora en la productividad de la Arthrospira platensis (spirulina) en una empresa dedicada a su producción. Se aplicó la metodología seis sigma en los procesos productivos que requieren el uso de biorreactores. Partiendo del análisis del estado actual, se identificaron aspectos, variables físicas y químicas que influyen directamente en la productividad alcanzada. Se probaron varios medios de cultivo que posteriormente se escalaron para su producción industrial. Además, se controló la incorporación de carbono al medio de cultivo, optimizando el rango de potencial hidrógeno pH. Se midieron los parámetros identificados y asignaron estrategias de la metodología seis sigma. Se comprobó una mejora en la productividad correspondiente al 66% con la misma calidad de producto final.

Métricas de enriquecimiento para la identificación de estabilizadores del cuarteto G telomérico usando algoritmo genético

AutanaBooks — Wed, 27 Jan 2021 23:23:03 +0100

En este estudio se encuentra detallada una combinación de herramientas computacionales de acoplamiento y cribado virtual, en 108 moléculas activas y 3620 señuelos para encontrar estabilizadores del cuarteto G (G4). Para tener resultados más precisos se aplicaron combinaciones de programas de acoplamiento con quince funciones de puntuación energética. La validación y evaluación de las métricas se realizó con el algoritmo genético CompScore. Los resultados evidenciaron un aumento en BEDROC y EF del 50% en comparación a otras estrategias, además de reflejar un reconocimiento temprano de moléculas activas. A partir de estos resultados es posible trabajar con las moléculas que presentaron un buen reconocimiento temprano y evaluar su efecto como estabilizadores de G4. De esta manera se garantiza resultados más eficientes y precisos en la etapa preclínica para el desarrollo de anticancerígenos.

Toxicidad producida por compuestos salinos en el proceso de germinación de Lactuca sativa

AutanaBooks — Wed, 27 Jan 2021 23:13:03 +0100

En este trabajo se presentar los resultados de la evaluación de toxicidad en los procesos germinativo y de crecimiento radicular de Lactuca sativa (Lechuga) por efecto del uso de compuestos salinos (NaCl, KCl and K2SO4). Se ha realizado ensayos en dos tipos de
especies de semillas de Lactuca sativa negra y roja. Para el proceso se inoculo a una misma concentración los tres medios salinos y las semillas se incubaron por un periodo de 6 días. Tras este periodo se evaluó la longitud de las raíces, número de semillas germinadas en cada medio salino. Se evidenció que la salinidad influye sobre la germinación de distinta manera para las semillas rojas y negras con referencia al medio de cultivo de control.

Introduction to FIBREGY project

Julio García-Espinosa — Mon, 25 Jan 2021 19:09:03 +0100

The overall objective of the FIBREGY project is to enable the extensive use of FRP materials in the structure of the next generation of large Offshore Wind and Tidal Power platforms. In order to achieve this objective, the project will develop, qualify and audit innovative FRP materials for offshore applications, elaborate new design procedures and guidelines, generate efficient production, inspection and monitoring methodologies, and validate and demonstrate advanced software analysis tools. Finally, the different developed technologies will be demonstrated by using advanced simulation techniques and building large and real-scale prototypes.

Analysis of beams on elastic foundations using Green's functions

Juan Camilo Molina-Villegas — Mon, 25 Jan 2021 14:17:03 +0100

Beams on elastic foundation are basic elements within structural analysis, which are used to model foundation beams, foundation piles, retaining walls, and more complex structures that include some of these elements. For their analysis, the finite element method is usually used [1], which produces an approximate solution of the problem; and the Green’s function stiffness method [2], which produces an exact solution. This article presents a methodology 100 % based on the use of Green function’s (response to a unit point force), to obtain the exact response of beams on elastic foundation. The main advantage of this formulation is its computational low cost compared to the aforementioned alternatives, and even for a large number of problems, it can be expressed only by means of sums and integrals, which can be easily performed numerically.

Also, a great variety of Green function’s for finite and infinite beams on elastic foundations with different boundary conditions are also presented, as well as some examples with the implementation of the proposed methodology.

Conservación del patrimonio marítimo flotante: marco normativo europeo y español. Con especial referencia al patrimonio marítimo de Ibiza y Formentera

Javier Calbet Roig — Sun, 24 Jan 2021 14:15:03 +0100

The aim of this project is to analyse the state of the Spanish floating maritime heritage and the causes which have led to the current situation: the deliberately sinking of ships, exports to foreign countries, fisheries structural policies and the lack of social and political awareness towards the conservation of the maritime heritage.

A short international vision allows the reader to know how conservacionist movements have benn carried out in countries with a similar maritime vocation as Spain. Furthermore, an analysis of the European, national and regional regulatory frameworks governing floating maritime heritage is carried out, with a particular emphasis on the recent project "Reglamento de buques y embarcaciones históricas y sus reproducciones singulares".

Lastly, various elements of maritime heritage existing in the islands of Ibiza and Formentera are listed and a file card is proposed for the inventary of traditionals boats.

La Reina tornarà al mar

Javier Calbet Roig — Sun, 24 Jan 2021 14:11:02 +0100

The present article wants to show the process of reconstruction of a classic sloop in the island of Ibiza.

D6.3 Report on stochastic optimisation for simple problems

Jesús Sánchez Pinedo — Thu, 14 Jan 2021 11:53:56 +0100

This report addresses the general matter of optimisation under uncertainties, following a previous report on stochastic sensitivities (deliverable 6.2). It describes several theoretical methods, as well their application into implementable algorithms. The specific case of the conditional value at risk chosen as risk measure, with its challenges, is prominently discussed. In particular, the issue of smoothness – or lack thereof – is addressed through several possible approaches. The whole report is written in the context of high-performance computing, with concern for parallelisation and cost-efficiency.

D5.3 Report on theoretical work to allow the use of MLMC with adaptive mesh refinement

Jesús Sánchez Pinedo — Wed, 13 Jan 2021 14:26:09 +0100

This documents describes several studies undertaken to assess the applicability of MultiLevel Monte Carlo (MLMC) methods to problems of interest; namely in turbulent fluid flow over civil engineering structures. Several numerical experiments are presented wherein the convergence of quantities of interest with mesh parameters are studied at different Reynolds’ numbers and geometries.

It was found that MLMC methods could be used successfully for low Reynolds’ number flows when combined with appropriate Adaptive Mesh Refinement (AMR) strategies. However, the hypotheses for optimal MLMC performance were found to not be satisfied at higher turbulent Reynolds’ numbers despite the use of AMR strategies.

Recommendations are made for future research directions based on these studies. A tentative outline for an MLMC algorithm with adapted meshes is made, as well as recommendations for alternatives to MLMC methods for cases where the underlying assumptions for optimal MLMC performance are not satisfied.

D6.4 Report on stochastic optimisation for unsteady problems

Jesús Sánchez Pinedo — Wed, 13 Jan 2021 13:57:10 +0100

This report brings together methodological research on stochastic optimisation and work on benchmark and target applications of the ExaQute project, with a focus on unsteady problems. A practical, general method for the optimisation of the conditional value at risk is proposed. Three different optimisation problems are described: an oscillator problem selected as a suitable trial and illustration case; the shape optimisation of an airfoil, chosen as a benchmark application in the project; the shape optimisation of a tall building, which is the challenging target application set for ExaQUte. For each problem, the current developments and results are presented, the application of the proposed method is discussed, and the work to be done until the end of the project is laid out.

D3.2 Report on parallel in time methods and release of the solvers

Jesús Sánchez Pinedo — Wed, 13 Jan 2021 13:51:27 +0100

In this deliverable we provide the details related to the design, implementation, and scalability analysis of Space Time Balancing Domain Decomposition by Constraints (STBDDC) preconditioners that have been implemented in the FEMPAR project [8]. First, we describe the state of the art of space-time methods in Sect. 2 and we then provide some details of our particular implementation in Sect. 3. Next, in Sect. 4, we present a detailed description of the numerical experiments performed during the project showing the excellent scalability results that these algorithms permit to achieve. At the same time, we show the limitations of these algorithms when dealing with nonlinear problems. Finally we draw some concluding remarks in Sect. 5.

D5.4 Report on MLMC for time dependent problems

Jesús Sánchez Pinedo — Wed, 13 Jan 2021 13:19:05 +0100

In this report, we study the use of Multi-Level Monte Carlo (MLMC) methods for time dependent problems. It was found that the usability of MLMC methods depends strongly on whether or not the underlying time dependent problem is chaotic in nature. Numerical experiments are conducted on both simple problems, as well as fluid flow problems of practical interest to the ExaQUte project, to demonstrate this. For the non-chaotic cases, the hypotheses that enable the use of MLMC methods were found to be satisfied. For the chaotic cases, especially the case of high Reynolds’ number fluid flow, the hypotheses were not satisfied. However, it was found that correlations between the different levels were high enough to merit the use of multi-fidelity or control-variate approaches. It was also noted that MLMC methods could work for chaotic problems if the time window of analysis were chosen to be small enough. Future studies are proposed to examine this possibility.

D7.2 Finalization of "deterministic" verification and validation tests

Jesús Sánchez Pinedo — Wed, 13 Jan 2021 12:30:47 +0100

This deliverable focus on the verification and validation of the solvers of Kratos Multiphysics which are used within ExaQUte. These solvers comprise standard body-fitted approaches and novel embedded approaches for the Computational Fluid Dynamics (CFD) simulations carried out within ExaQUte. Firstly, the standard body-fitted CFD solver is validated on a benchmark problem of high rise building - CAARC benchmark and subsequently the novel embedded CFD solver is verified against the solution of the body-fitted solver. Especially for the novel embedded approach, a workflow is presented on which the exact parameterized Computer-Aided Design (CAD) model is used in an efficient manner for the underlying CFD simulations.

It includes:

A note on the space-time methods
Verification results for the body-fitted solver based on the CAARC benchmark
Workflow consisting of importing an exact CAD model, tessellating it and performing embedded CFD on it
Verification results for the embedded solver based on a high-rise building
API definition and usage

D1.3 First public Release of the solver

Jesús Sánchez Pinedo — Tue, 12 Jan 2021 13:46:56 +0100

This deliverable presents the software release of Kratos Multiphysics, together with the XMC library, Hyperloom and PyCOMPSs API definition [8]. This report is meant to serve as a supplement to the public release of the software. Kratos is “a framework for building parallel, multi-disciplinary simulation software, aiming at modularity, extensibility, and high performance. Kratos is written in C++, and counts with an extensive Python interface”. XMC is a python library for hierarchical Monte Carlo algorithms. Hyperloom and PyCOMPSs are environments for enabling parallel and distributed computation.

D1.1 Solvers "stub" implementation of the capabilities to be delivered

Jesús Sánchez Pinedo — Tue, 12 Jan 2021 12:59:31 +0100

The current deliverable describes the initial API available for the solvers. The API is intended to be based on the Kratos Multiphysics fraemework and will evolve during the project. The current deliverable describes the essential features of the interface and provides an initial working implementation to be used as a basis for the future developements.

The initial implementation described here is currently operative on the master branch of Kratos. As of the end of July 2018 (moment of handing in of current deliverable) the interface is operative and is being used “in production”. Nevertheless, it still does not fully support the model serialization capabilities that are needed for pyCompSS and HyperLoom.

The interface is documented in the project wiki page [wiki]. The same documentation is also presented in the current deliverable.

D1.4 Final public Release of the solver

Jesús Sánchez Pinedo — Tue, 12 Jan 2021 12:48:00 +0100

This deliverable presents the final software release of Kratos Multiphysics, together with the XMC library, Hyperloom and PyCOMPSs API definitions [13]. This release also contains the latest developements on MPI parallel remeshing in ParMmg. This report is meant to serve as a supplement to the public release of the software. Kratos is “a framework for building parallel, multi-disciplinary simulation software, aiming at modularity, extensibility, and high performance.

Kratos is written in C++, and counts with an extensive Python interface”. XMC is “a Python library for parallel, adaptive, hierarchical Monte Carlo algorithms, aiming at reliability, modularity, extensibility and high performance“. Hyperloom and PyCOMPSs are environments for enabling parallel and distributed computation. ParMmg is an open source software which offers the parallel mesh adaptation of three dimensional volume meshes.

D2.2 First release of the octree mesh-generation capabilities and of the parallel mesh adaptation kernel

Jesús Sánchez Pinedo — Tue, 12 Jan 2021 12:35:18 +0100

This document presents a description of the octree mesh-generation capabilities and of the parallel mesh adaptation kernel. As it is discussed in Section 1.3.2 of part B of the project proposal there are two parallel research lines aimed at developing scalable adaptive mesh refinement (AMR) algorithms and implementations. The first one is based on using octree-based mesh generation and adaptation for the whole simulation in combination with unfitted finite element methods (FEMs) and the use of algebraic constraints to deal with non-conformity of spaces. On the other hand the second strategy is based on the use of an initial octree mesh that, after make it conforming through the addition of templatebased tetrahedral refinements, is adapted anisotropically during the calculation. Regarding the first strategy the following items are included:

Description of the octree-based AMR kernel with space-filling curves.
Description of a outer, wrapping AMR layer supporting FEM needs.
Numerical results in a distributed environment.

Regarding the second strategy the following items are included:

An outline of the anisotropic mesh adaptation algorithm.
A description of the state of the art of the implementation.
A discussion on the ongoing and future work.

D1.2 First realease of the softwares

Jesús Sánchez Pinedo — Tue, 12 Jan 2021 11:49:23 +0100

This deliverable presents the software release of the Kratos Multiphysics software [3], ”a framework for building parallel, multi-disciplinary simulation software, aiming at modularity, extensibility, and high performance. Kratos is written in C++, and counts with an extensive Python interface”. In this deliverable we focus on the development of Uncertainty Quantification inside Kratos. This takes place in the MultilevelMonteCarloApplication, a recent development inside the software that allows to deal with uncertainty quantification.

CHILDREN’S RIGHTS TO EDUCATION IN SOUTH AFRICA TWENTY YEARS AFTER DEMOCRACY: A REFLECTION ON ACHIEVEMENTS, PROBLEMS AND AREAS FOR FUTURE ACTION

BELLITA BANDA CHITSAMATANGA — Fri, 08 Jan 2021 01:27:02 +0100

Education is the most powerful weapon that can be used to change the world. These noble words by Nelson Mandela provide a yardstick against which South Africa can measure whether the rights of the child, key of which is the right to education, are progressively being realised. Towards this end, education is seen as the ultimate foundation and solution for the attainment of freedom, democracy and human rights; social justice and equality for South African children. Thus, the question remains: after more than twenty years of democracy, to what extent can South Africa pride herself of having achieved this noble goal? This article reflects on the national effort to realise the rights of children to education against the frameworks provided for in international and regional instruments. The latter require governments’ commitment to ensure that the rights of children to education in particular, are implemented and respected. An analysis will be made on how the new democratic government has succeeded to reverse the discriminatory policies, law and practice of the apartheid era. It further discusses how the existing education system translates the attainment of children rights to education in terms of the standard and quality of teaching and learning; existing school facilities; racial segregation; human and financial resources; and safe school learning environment. The article concludes by identifying measures that need to be taken by all stakeholders in order to promote the realisation of children’s right to education.