Integral equations of a cohesive zone model for history-dependent materials and their numerical solution

A nonlinear history-dependent cohesive zone (CZ) model of quasi-static crack propagation in linear elastic and viscoelastic materials is presented. The viscoelasticity is described by a linear Volterra integral operator in time. The normal stress on the CZ satisfies the history-dependent yield condition, given by a nonlinear Abel-type integral operator. The crack starts propagating, breaking the CZ, when the crack tip opening reaches a prescribed critical value. A numerical algorithm for computing the evolution of the crack and CZ in time is discussed along with some numerical results

Modernism and Moral Philosophy: Ethical Paradigms in the Late Interwar Literature of Virginia Woolf and T. S. Eliot

This study will focus on the period between 1930 and the start of the Second World War to argue that the later social and political developments of the interwar years had a profound impact on the ethical ideas expressed in the late works of the two seminal Modernist writers: Virginia Woolf and T. S. Eliot. These writers were singularly engaged in rethinking the foundations of philosophical ethics, and their late works illustrate how the political context of the 1930s helped to reshape their perspectives on ethical concerns about the role of art and the artist in times of crisis, the necessary characteristics of public discourse, identity and community, and the possible sources of moral guidance. This research will begin with a discussion about the triangular relationship between late Modernism, war, and ethics to establish that there is an inextricable connection between the historical milieu in which the late works of these writers emerged and the way that they understood and wrote about ethics. The first chapter on Woolf will highlight her critique of modern Western academia to examine her ethical discourse on identity, epistemic violence, and the public writer in The Years (1937), Three Guineas (1938), Between the Acts (1941) and “Anon” (1940-1941). The second chapter on Eliot will examine his late works, particularly Murder in the Cathedral (1935), The Idea of a Christian Society (1939) and Four Quartets (1943) to show how Eliot’s 1927 conversion to Anglo-Catholicism and his disillusionment with British liberal democracy in the 1930s informed his ideal of a Christian community and his vision of the ethics of liturgy. These chapters will explore the ethical paradigms in their late works to suggest that both Woolf and Eliot offered distinctive and valuable discourses on interwar ethics

Mapping the landscape of research on workplace sexual discrimination: A bibliometric analysis

Sexual discrimination in the context of the work environment is an adverse phenomenon where individuals are treated unfairly or unequally based on their gender or sexual orientation. This study aims to trace the evolution of the literature surrounding sexual discrimination in the workplace over time. Bibliometric methods were used in this study to review 298 research samples conducted between 1986 and 2023. The data was obtained from the Scopus database. The reason for using Scopus as the main reference data in this study is because the Scopus database is a citation and abstract index database that covers a wide range of scientific literature and focuses on various fields of science published worldwide in high-quality journals with comprehensive and representative data to accurately identify research trends and academic impact. Besides, the features provided by Scopus greatly facilitate in-depth bibliometric analysis. The focus of this study lies on scientific performance evaluation and literature mapping using Vosviewer and BibExcel tools. The research findings confirmed a significant increase in the number of publications and citations on this topic over the past five years. In addition, cross-disciplinary collaboration seems to have made an important contribution, involving the fields of health, law, psychology, as well as other social sciences. However, this study indicates the limitations of interdisciplinary cooperation in generating a more holistic and comprehensive understanding of this phenomenon

Multi-phase-field analysis of short-range forces between diffuse interfaces

We characterize both analytically and numerically short-range forces between spatially diffuse interfaces in multi-phase-field models of polycrystalline materials. During late-stage solidification, crystal-melt interfaces may attract or repel each other depending on the degree of misorientation between impinging grains, temperature, composition, and stress. To characterize this interaction, we map the multi-phase-field equations for stationary interfaces to a multi-dimensional classical mechanical scattering problem. From the solution of this problem, we derive asymptotic forms for short-range forces between interfaces for distances larger than the interface thickness. The results show that forces are always attractive for traditional models where each phase-field represents the phase fraction of a given grain. Those predictions are validated by numerical computations of forces for all distances. Based on insights from the scattering problem, we propose a new multi-phase-field formulation that can describe both attractive and repulsive forces in real systems. This model is then used to investigate the influence of solute addition and a uniaxial stress perpendicular to the interface. Solute addition leads to bistability of different interfacial equilibrium states, with the temperature range of bistability increasing with strength of partitioning. Stress in turn, is shown to be equivalent to a temperature change through a standard Clausius-Clapeyron relation. The implications of those results for understanding grain boundary premelting are discussed.Comment: 24 pages, 28 figure

Synthesis and Characterization of PVA-Enzyme/GA/PPy/ PVC-KTpClPB-o-NPOE Indicator Electrodes, XRD Analysis, FTIR and Variable Signal Analysis

This study aims to synthesize and characterize PVA-Enzyme/GA/PPy/PVC-KTpClPB-o-NPOE indicator indicator electrodes, XRD and FTIR analysis and variable signal analysis for urea sensors. The method used is biosensor potentiometry with urease enzyme immobilization technique which analytes urea. Modify 6 mg of enzyme from the amount of 1 drop and 3 drops in 0.5 mL (50% water: 50% ethanol) in PVA solution and o-NPOE plasticizer in PVC-KTpClPB. The indicator electrode is designed in multi-membrane, namely PVA-Enzyme/GA/PPy/PVC-KTpClPB-o-NPOE. PPy was dissolved in H2SO4 at a concentration of 8 M. Modification of PVA-Enzyme/(GA 2.9%)/PVC-KTpClPB-(o-NPOE 61%) was carried out in one layer each. The number of enzyme drops to see the difference in the intensity of the XRD diffraction spectrum and the difference in the transmittance of the FTIR spectrum from the indicator electrode with multi membrane modified PPy with H2SO4 denoted H2SO4-1 and H2SO4-3, respectively. The best results were obtained on the indicator electrode with the notation H2SO4-

Characterization of PVA-Enzyme Coated Indicator Electrodes GA coated again with PVC-KTpClPB-o-NPOE SEM-EDS, FTIR and XRD analysis

This study aims to characterize the tungsten-urea analyte indicator electrode. The method used is biosensor potentiometry with urease enzyme immobilization technique. This indicator electrode was coated with PVA-enzyme coated with glutaraldehyde (GA) 2.9% coated with PVC-KTpClPB- o-NPOE with o-NPOE variation of 61% and 66%. Characterization of coated indicator electrodes using SEM-EDS, FTIR and XRD analysis. A1-4 61% indicator electrode sample coated PVA-enzyme 1x coated with glutaraldehyde (GA) 2.9% 1x coated PVC-KTpClPB- o-NPOE 1x, with o-NPOE 61%. A3-4 61% indicator electrode sample coated PVA-enzyme 3x coated with glutaraldehyde (GA) 2.9% 1x coated PVC-KTpClPB- o-NPOE 1x, with o-NPOE 61%. Likewise, the reasoning of samples A1-4 66% and A3-4 66%. There are four indicator electrodes made with the notation A1-4 61%, A1-4 66%, A3-4 61% and A3-4 66%. The best results were obtained at the indicator electrode sample A1-4 61%, contributing to the urea sensor of the potentiometer cel

Characterization of PVA-Enzyme Coated Indicator Electrodes GA coated again with PVC-KTpClPB-o-NPOE UV-Vis analysis, variable signal analysis, sensor sensitivity and SEM-EDS

This study aims to characterize the phosphate buffer and urease enzymes through UV-Vis and SEM-EDS absorbance spectra using tungsten as an indicator electrode. The method used is a potentiometric biosensor with urease enzyme immobilization technique for urea analyte. A small detection range of 10-5-10-4M has been studied with PVA-enzyme coated indicator electrodes coated with PVC-KTpClPB. On this basis, the researchers increased the detection range by analyzing glutaraldehyde (GA) mixed with PVA-enzyme and o-NPOE mixed with PVC-KTpClPB. The best results of GA mixed PVA-enzyme at GA2.9% UV-Visible analysis. The best results were PVA-enzyme coated indicator electrodes coated with GA coated again with PVC-KTpClPB-o-NPOE SEM-EDS analysis on PVA-enzyme samples 3x coated with GA 1x and PVC-KTpClPB-o-NPOE 1x with o-NPOE variation of 61% and 66%

Study On Optimization Of Composite Tubular Energy Absorption System

A four-phase program to improve the specific energy absorbed by axially crushed composite collapsible tubular energy absorber devices was undertaken. In the first phase, the effects of trigged tube wall on the crushing behaviour were investigated. At this stage, triggered tubes were fabricated and crushed. The second phase is aimed at obtaining the best position for the triggered wall. The third phase focuses on the effects of material sizing in order to understand the influence of triggered wall Iength on the responses of composite circular tubes to the axial crushing load. The results from these three phases lead to the fourth phase. The objective of the 4t" phases was to optimise the shape geometry of the cross-section area to further improve tube energy absorption capability. The tubes were manufactured from woven roving glasslepoxy fabric and had the same lay-up providing a common laminate for comparison. The failure modes were observed and the specific sustained crushing loads were determined and compared against non-optimized tubes of the same lay-up. The importance of differentiating between initiation energy and propagation energy is shown, and a new parameter (energy capability index (ECI)) is proposed, as a useful measure for comparing crush behaviour of composite structures. The experimental results demonstrated strong potential benefits of optimizing the material distribution. The sizing and shape optimization of composite collapsible tubes exhibited a pronounced effect on their capability to absorb high specific energy under axial compressive load. For the effect of triggering it was that tubes (TN) observed to experience catastrophic failure mode during the post crush stage also displayed very poor energy absorption. Triggering a part of tube wall was very efficient in improving the energy absorption capacity of circular composite tubes. Accordingly tubes with triggered wall (T-tubes) exhibited highest energy absorption capacity compared with non-triggered tubes. They also experience stable post-crush region of loaddisplacement curves, which leads to high crashworthiness performance. It is also evident from the experimental results that change in the triggered wall aspect ratio significantly affected the energy absorption capability of tube with middle triggered wall (TM-tubes). Distinct differences were observed between the different aspect ratio, where TM tubes (i.e. tubes with triggered wall aspect ratio of 0.28) exhibited the highest energy absorption capacity. Different failure modes were observed for different triggered wall length ratios (Lt,/H). For the core tubes (TMC-), was observed that core presence markedly improved the energy absorption capacity of composite circular tubes. Among TMC- tubes, TMC3 tubes (i.e. tubes with core thickness of 3.35mm) displayed highest energy absorption capacity