MPFEM Modeling on the Compaction of Al/SiC Composite Powders with Core/Shell Structure

Uniaxial die compaction of two-dimensional (2D) Al/SiC core/shell (core: SiC; shell: Al) composite powders with different initial packing structures was numerically reproduced using DEM-FEM coupled MPFEM modeling from particulate scale. The effects of external pressure, initial packing structure, and SiC content on the packing densification were systematically presented. Various macro and micro properties such as relative density and distribution, stress and distribution, particle rearrangement (e.g. sliding and rolling), deformation and mass transfer, and interfacial behavior within composite particles were characterized and analyzed. The results show that by properly controlling the initial packing structure, pressure, and SiC content, various anisotropic and isotropic Al/SiC particulate composites with high relative densities and uniform density/stress distributions can be obtained. At early stage of the compaction, the densification mechanism mainly lies in the particle rearrangement driven by the low interparticle forces. In addition to sliding, accompanied particle rolling also plays an important role. With the increase of the compaction pressure, the force network based on SiC cores leads to extrusion on Al shells between two cores, contributing to mass transfer and pore filling. During compaction, the debonding between the core and shell of each composite particle appears and then disappears gradually in the final compact

Service network design in inland waterway liner transportation with empty container repositioning

inland shipping has been playing a more and more important role in integrated transportation system, the optimization of such a network with empty containers repositioning is of great practical significance to raise inland shipping service level so as to promote freight mode shift from land to water. This paper addresses the construction of system service network for inland water containers transportation (IWCT). We incorporate the specific natures of inland waterway containers transportation and formulate the inland waterway system containers transportation into a mathematic model. It is a complex giant problem to optimize routing and fleet deployment for the whole network at the same time. Thus, a combined algorithm with genetic algorithm (GA) and Integer programming (IP) calculations are designed to solve this program. Further, a network of Yangtze River ports is studied. A set of shipping routes, including the calling ports, service frequency and type of the used ship of each route are figured out by the IWCT network optimization model. This set of shipping routes is a combination of short routes and long routes. The direct links are commonly used for moving large quantities of containers between two ports. While for small containers flow, longer routes are used to bund cargo flows by calling as many ports as possible. Most present network optimization studies are focused on network design and fleet deployment about ocean and coastal container shipping. However the features of inland water shipping network are different and related studies are rare. This paper aims to fill this gap. Taking the specific features of IWCT into consideration, the proposed model is suitable for the service network design in IWCT network. And the experimental results verify the validity of the combined algorithm. Point-to-point direct route is the most economic mode for large cargo flows between ports. When the containers flow is small, routes calling at multiple ports can achieve economies of scale through bundling. Document type: Articl

An exploration of factors related to quality of life in Indonesian care workers in home-based care settings

Background Indonesians constituted 79% of foreign care workers for long-term care in Taiwan in 2015. Therefore, it is crucial to explore the effect of work stress and quality of life (QoL) on this population.Purpose This study aims to explore stress levels, social support requirements, and perceived QoL among Indonesian care workers (ICWs) who work in home care settings.Methods A cross-sectional design was used. Data were collected between 2014 and 2016 from a convenience sample of ICWs working in eastern Taiwan using a self-administered questionnaire that comprised the Stress Perception Scale (SPS), Social Support Scale (SSS), and World Health Organization Quality of Life-Brief scale. One hundred fifty-seven valid questionnaires were collected. The response rate was 80.51%. Data were analyzed using descriptive statistics, one-way analysis of variance, Pearson's correlation coefficient, and multiple regression analysis.Results The results found that the average SPS of the sample was 70.50, with low QoL scores and requirements for more social support. In addition, significant and positive correlations were found between QoL and SPS, SSS, duration of patient care, and hours of care per week. Stepwise regression analysis showed that the most predictive variables for QoL were time spent caring, preservice training, psychological stress, and emotional support, which together accounted for 60.9% of the total variance.Conclusions/Implications for Practice This study facilitated understanding of the stress on ICWs and the impact of social support on their QoL. The findings suggest that new immigrants in Taiwan should be introduced to foreign care workers or nursing attendants. Moreover, long-term-care-related teachers should work with home care institutions or agencies to develop a teaching model for innovative care skills to relieve the perceived stress of ICWs

Filtering germs: Groupoids associated to inverse semigroups

We investigate various groupoids associated to an arbitrary inverse semigroup with zero. We show that the groupoid of filters with respect to the natural partial order is isomorphic to the groupoid of germs arising from the standard action of the inverse semigroup on the space of idempotent filters. We also investigate the restriction of this isomorphism to the groupoid of tight filters and to the groupoid of ultrafilters.Comment: 9 pages. This version matches the version in Expositiones Mathematica

Novel N,S-phenacyl protecting group and its application for peptide synthesis

The phenacyl group can be introduced onto amino and thio groups by N,S-alkylation reactions. Conversely, these groups are removed rapidly by employing magnesium in acetic acid. This protecting group was successfully applied to a short peptide synthesis of Boc-L-Cys-Gly-OMe

Sulforaphane induces adipocyte browning and promotes glucose and lipid utilization

Scope: Obesity is closely related to the imbalance of white adipose tissue storing excess calories, and brown adipose tissue dissipating energy to produce heat in mammals. Recent studies revealed that acquisition of brown characteristics by white adipocytes, termed “browning,” may positively contribute to cellular bioenergetics and metabolism homeostasis. The goal was to investigate the putative effects of natural antioxidant sulforaphane (1-isothiocyanate-4-methyl-sulfonyl butane; SFN) on browning of white adipocytes. Methods and Results: 3T3-L1 mature white adipocytes were treated with SFN for 48 h, and then the mitochondrial content, function, and energy utilization were assessed. SFN was found to induce 3T3-L1 adipocytes browning based on the increased mitochondrial content and activity of respiratory chain enzymes, whereas the mechanism involved the upregulation of nuclear factor E2-related factor 2/ sirtuin1/ peroxisome proliferator-activated receptor gamma coactivator 1 alpha signaling. SFN enhanced uncoupling protein 1 expression, a marker for brown adipocyte, leading to the decrease in cellular ATP. SFN also enhanced glucose uptake and oxidative utilization, lipolysis and fatty acid oxidation in 3T3-L1 adipocytes. Conclusion: SFN-induced browning of white adipocytes enhanced the utilization of cellular fuel, and the application of SFN is a promising strategy to combat obesity and obesity-related metabolic disorder