73 research outputs found
Tensile Properties of Glass Fiber Reinforced Polyamide 6-Polypropylene Composites
In this research study, glass fiber (GF) reinforced polyamide 6 (PA6)-polypropylene blends were prepared using injection molding machine. Test specimens of five different compositions such as, 70%PA6+30%PP, 65%PA6+30%PP+5%GF, 60%PA6+30%PP+10%GF, 55%PA6+30%PP+15%GF and 50%PA6+30%PP+20%GF were prepared successfully. The effects of glass fiber content on the tensile properties of the composites were investigated. Test results reveal that yield strength, elastic modulus, tensile strength and tensile elongation are influenced by glass fiber content. Results show that yield strength is low for 70%PA6+30%PP pure polymer blend whereas 50%PA6+30%PP+20%GF composite shows high yield strength. Test results also show that elastic modulus is low for 70%PA6+30%PP, it increases with the increase in fiber content and elastic modulus is remarkably high for 50%PA6+30%PP+20%GF composite. On the other hand, tensile strength is low for 70%PA6+30%PP blend and tensile strength of GF reinforced composite increases steadily with the increase in glass fiber content. In addition, the tensile elongation of 70%PA6+30%PP pure blend is very high, whereas the composite shows reduced tensile elongation with the increase in fiber content and particularly, 50%PA6+30%PP+20%GF composite shows notably low tensile elongation
Maternal Depression and Its Associated Factors among the Mothers at Narayanganj in Bangladesh
Maternal depression is becoming a serious public health concern in the world day by day. The purpose of the current study was to assess the maternal depression and its associated factors among the mothers of Narayanganj city in Bangladesh. A cross-sectional study was conducted in six different areas at Narayanganj in Dhaka among 377 mothers having children of five to ten years between the periods of May, 2019 to September, 2019. The respondents were selected by simple random sampling method. All data analysis was done by using IBM SPSS version 20.0. The mean age of the pregnant women was 26±4 years. It was found that about 77% of mothers had high depressive symptoms whereas 10.7%, 6.63% and 6.36% of mothers had moderate, mild and no depressive symptoms, respectively. It was observed that family income, family size, age of children and age at marriage were significantly (p<0.05) associated with maternal depression status. Further investigations might be carried out to assess the effect size of the associated factors mentioned above. Keywords: Maternal depression, mothers, children, associated factors. DOI: 10.7176/JHMN/102-06 Publication date:September 30th 2022
Investigation on microstructure and hardness of aluminium-Aluminium oxide functionally graded material
This study investigated the microstructure and hardness of aluminium-aluminium oxide (Al-Al2O3) functionally graded material (FGM). Preparation of metal-ceramic functionally graded material was carried out following powder metallurgy (PM) route. Four-layered aluminium-aluminium oxide (Al-Al2O3) graded composite structure was processed using 0%, 5%, 10% and 15% (from first layer to fourth layer) aluminium oxide as ceramic concentration. A cylindrical steel die was used for the fabrication process of the FGM green compact. The green compact was prepared by applying cold pressing technique using a hydraulic press. The sintering process was implemented at 600 °C sintering temperature and 3 h sintering time using 2-step cycle. Microstructural characterization of the sample was conducted layer by layer using high resolution optical microscopy (OM). Hardness of the sample was also performed layer by layer using Vickers microhardness tester. The obtained results revealed that there is a uniform ceramic particle distribution within the metallic phase. From the microstructural observation it was clear that smooth transition occurred from one layer to next layer and each interface was distinct. It was also observed that there is a steady increase in layer hardness with the increase in ceramic concentration
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Advanced Surface Engineering Research
Surface engineering has rapidly expanded in recent years as the demand for improved materials has increased. Surface engineering is a valuable tool for conceiving both surface and bulk properties, which cannot be achieved simultaneously either by the coating material or by the substrate material alone. The book is written on the current trends of surface engineering and relevant research. The applied and basic research as well as some worthy concepts of materials related to this area is explained clearly to understand the need for surface engineering in industrial applications. The different surface modification processes, properties, and their characterizations are discussed elaborately for future research and as a text book. Modification of surface properties by films or coatings is used in industrial applications. This is an area of interest to numerous fields: fabrication of parts, mechanics, transport, catalysis, energy, production, microelectronics, optoelectronics, the leisure industry, etc. The properties are considered for protection against corrosion, oxidation or wear, biocompatibility, wetting, adhesion, durability, catalytic activity, and toughness. The modern concept of engineering is discussed to ensure that the contributions of this subject minimize energy consumption. The book will be used as a state of the art for present and future researchers, industrial components design, and control
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