Abstract

Mutated transthyretin-associated (ATTRm) amyloidosis with heart failure is associated with decreased longitudinal left ventricular (LV) myocardial contraction, as measured by strain Doppler echocardiography. We sought to clarify whether speckle-tracking echocardiography (STE) would provide useful information in patients with ATTRm cardiac amyloidosis. One hundred twenty-three consecutive patients with ATTRm amyloidosis were divided into 3 groups. Group 1 had no evidence of cardiac involvement (n = 47), group 2 had heart involvement but no congestive heart failure (CHF) and/or serum brain natriuretic peptide (BNP) levels < 100 pg/mL (n = 35), and group 3 had heart involvement and CHF and/or serum BNP levels ≥ 100 pg/mL (n = 41). All patients underwent standard 2-dimensional (2D), Doppler echo, and STE. By standard 2D and Doppler echo, differences in parameters were only apparent between group 3 and groups 1 and 2. Global circumferential strains by STE at each LV level and LV torsion were different between group 1 and groups 2 and 3, but not between group 2 and group 3. In contrast, global longitudinal LV strain showed significant intergroup differences (− 17.3 ± 2.3%, − 13.3 ± 2.3%, − 9.9 ± 3.3% for groups 1 to 3, respectively, P < 0.0001). Radial strain also showed significant intergroup differences for each basal LV segment. Among 41 patients who could have been followed up after 1 year, 34 patients with diflunisal treatment had shown improvement in apical rotation and torsion without deterioration in multidirectional strains. ATTRm cardiac amyloidosis is characterized by progressive impairment in longitudinal and basal LV radial function when global circumferential shortening and torsion remain unchanged.

Abstract

The diagnosis of thrombus in the left atrium in patients with persistent atrial fibrillation (AF) and may be inconsistent because of variability in thrombus morphology. In some cases it is challenging and requires unusual approach. New Doppler-derived methods might be helpful to identify such thrombi. We evaluated quantitative differences in mechanical function of the left atrial appendage (LAA) basal segments using tissue Doppler imaging (TDI)and speckle tracking echocardiography (STE) in patients with non-valvular AF with and without LAA thrombus and compared them with SR patients. A total of 80 patients with normal left ventricular ejection fraction underwent transesophageal echocardiography (40 patients with SR and 40 patients with AF on oral anticoagulants including patients with LAA thrombus). We analyzed the basal segments of LAA including left lateral ridge (LLR) and baso-medial appendage segment (BMAS). Quantitative analysis was used to calculate peak velocity, average velocity, strain, strain rate and deformation. In patients with AF the lower LLR strain rate was the sole new STE significant parameter differentiating patients with and without LAA thrombi: − 0.9(− 1.2, − 0.1)s− 1 vs. − 1.6(− 1.9, − 1.3)s− 1, (p = 0.004). Additionally, patients in SR demonstrated significantly better peak velocity, average velocity, strain, strain rate and deformation than those with AF (p < 0.001). LLR appeared to be an appropriate site for measuring Doppler derived parameters. It is possible that the strain rate in LLR area may be a novel parameter correlating with the presence of thrombus in patients with AF.

Abstract

The research evaluates the behavior of a material when a plastic deformation occurs. The document describes the analytical process, finite elements and integrate process in order to develop shaped piece plan. Stress analysis and section variation were analyzed during the stuffing process. In the experimental part, the mechanical characteristics of the aluminum ASTM A1200 were determined (Yield strength was 214 MPa). The shaping process was carried out in a 5 tons press with pneumatic device. Several tests were executed with different depths in order to compare thicknesses with the physical model simulation. The maximum error was 3.67 % at 15 mm depth and the minimum of 0.24 % with the total depth. Respect to the efforts generated during the conforming, the maximum and minimum errors were 10.9 % and 2.18 % respectively.

Abstract

This paper presents the main physical parameters, dependencies, calculation methods in the physical structural-energy theory of the strength of a deformed solid. The initial physical and mechanical parameters of the strength of steel 45 were determined analytically. The physical methods were used to calculate the durability, fatigue, and steel damage for non-stationary mechanical and thermal loads. The relationship between physical and mechanical strength parameters is analytically determined. The results of calculations of the modified characteristics of the strength of the damaged material are presented, plastic deformations, cyclic stresses of arbitrary shape, and temperature conditions are taken into account. The originality of the study consists in that we used our own program for calculating the new characteristics of the damaged material for different stress functions. The application value of the research is that the physical method allows to analyze the data of load sensors, indentation according to ISO 14577 in the elements of machines. The physical parameters of the material and the new theoretical calculation methods can be used to control the state of the strength of the machinery mechanisms during operation.

Abstract

Due to external interference, pipelines used for onshore as well as offshore operations can present dent and gouge defects. As such defects can seriously impair facilities’ integrity and performance, it is necessary to evaluate the strains in the vicinity of these defects. The development of non-destructive approaches to assess defects severity remains an issue in the pipeline industry. In the present study, micro-hardness - strain relationships are established for three steel grades of pipeline materials: API X52 modern, API X52 vintage and API X63 vintage. The micro-hardness – strain correlations of the three pipe materials are analyzed in order to verify if they can be described by a master curve. For that purpose, Notched Tensile (NT) tests are performed in Longitudinal (L) and Transverse (T) directions for each grade in order to reach high strain values (up to 70%). The relationship proposed by Tabor was improved with the introduction of three new parameters that allow considering actual material behavior.

Abstract

This paper presents the methodology for calculating the peak deviator stress and strain at peak deviator stress uncertainty of triaxial compression tests on water saturated, non-cohesive soils consolidated under isotropic conditions. A silicious sand sample is prepared in the same way to produce identical cylindrical specimens. These are then tested under the same conditions. Type A and type B uncertainty are calculated separately and used to yield the combined and expanded uncertainty of the main results, peak deviator stress and strain at peak deviator stress. For both measurands, type A uncertainty is significantly higher that type B and it is the factor mainly affecting the overall uncertainty of the results

Abstract

The paper focuses on the long-term monitoring of the Milan Cathedral. After a concise historic background on the monument and the description of the sensing devices installed in the church, selected results obtained during the first year of static monitoring are summarized as well as the lessons learned in view of the Structural Health Monitoring (SHM) of the Cathedral. In more details, the time evolution of different static features (i.e. strain of metallic tie-rods and tilt of columns) is presented, along with the correlation between those features and the environmental parameters and the possible minimization/removal of the environmental effects with SHM purposes.