Effects Of Attrition Research Articles

MODERN METHODS AND ANCIENT TECHNOLOGIES OF RESTORATION AND RESTORATION OF SHOES

Restoration and restoration of shoes – a delicate, complex, often jewelry. It requires professionalism, experience, creative and creative approach and innate artistic taste of the master. In addition, restoration work often requires special equipment and materials for a number of rare and complex operations to completely restore the product and give it its original appearance or, conversely, “aging” of new shoes at the request of the customer. Shoe restoration allows a specialist to create using standard and non-standard materials, classic and advanced methods and techniques for replacing worn parts in the product, and also allows you to experiment with finishing compositions to give the product the appearance of “wear” and “abrasion”, creating a “faded” “Color of the material and its” aged “structure, the effect of attrition or patina, metallic luster or vice versa giving the product a look of” rejuvenation “by updating the color, giving it strength, shine, overall finish and strengthening the structure of the material as a whole. Thanks to such methods of restoration it is possible to achieve not just the desired, but also almost unique result of work. The features of the stages of shoe restoration are investigated in the article. Technological stages of restoration of footwear and step-by-step technology of finishing of finished products have been developed. A full cycle of restoration works was carried out on samples of men’s shoes worn. Tested according to the requirements of the standards and experimentally proven high wear resistance of the surface of the materials of the restored shoes, namely: the ability of the material to repeated bending, stretching, wet and dry friction. Experimental wearing of restored shoe samples was carried out. The high operational characteristics of the studied products have been confirmed. The expediency of these works has been proved experimentally.

Revealing the effects of mechanical attrition applied on Eskisehir-Beylikova REE ore utilizing MLA

Eskişehir-Beylikova ore has one of the high-potential rare earth element (REE) reserves worldwide. In addition to recovering of REEs from these ores, industrial-scale enrichment of barite, fluorite and thorium continues intensively. However, there have been problems with beneficiation due to the particle size liberation. The most significant point for selecting beneficiation method in a cost-effective way depends on the characterization studies that reveal the mineralogy, mineral associations, and liberation size. According to the recent studies that focused on the beneficiation of Eskişehir ore, it was pointed out that REEs accumulated – 5 µm and before beneficiation of those minerals mechanical attrition was needed. However, the effects of mechanical attrition and how it affects behaviors of the rare earth in the fine fractions have not explained clearly. Therefore, this research has focused on filling this gap in the literature to reveal the effects of mechanical attrition on the beneficiation of rare earth elements using the MLA technique. Regarding results, after the mechanical attrition process, the amount of −38 µm increased by 20 % in the scrubbed sample, and the distribution of REEs enhanced from 15 % to 70 %. The liberation degree of REEs enhanced by 10–25 %, and mineral associations decreased at – 38 µm. From EDS results, Rare earth carbonate, Th-Parisite, Synchysite, Carbocernaite, and Monazite were determined as the rare earth minerals.

Rehabilitating an attrited language in a bilingual person with aphasia

ABSTRACT Language difficulties can arise from reduced exposure to any given language (e.g. attrition) or after brain damage (e.g. aphasia). The manifestations of attrition and aphasia are often similar so differentiating between their effects on language loss and recovery is challenging. We investigated treatment effects for an English-Hebrew bilingual person with stroke-induced aphasia who had minimal contact with his Hebrew for over 14 years. We asked whether his attrited language could be rehabilitated, how effects of attrition and aphasia can be dissociated, and how such dissociation aids our understanding of the mechanisms involved in language recovery in aphasia. We administered a verb-based semantic treatment in Hebrew three times a week for six weeks (totalling 29 hours of therapy) and assessed changes in both Hebrew and English comprehension and production abilities across a variety of language tasks. Quantitative analyses demonstrated improvement in Hebrew production across language tasks, including those involving lexical retrieval processes that were trained during treatment. Improvement to English occurred in these same lexical retrieval tasks only. We interpret these results as indicating that the participant’s attrited language (Hebrew) could be rehabilitated with both specific treatment and general exposure to Hebrew contributing to improvement. Furthermore, treatment effects transferred to the untreated English. Qualitative analyses indicated that an interaction among aphasia, incomplete mastery of Hebrew pre-stroke, and attrition contributed to the participant’s language difficulties post-stroke. We conclude that partially shared underlying mechanisms of attrition and aphasia drive language processing and changes to it with treatment.

Secondary Dentin Formation Mechanism: The Effect of Attrition.

Human dentin consists of a primary layer produced during tooth formation in early childhood and a second layer which first forms upon tooth eruption and continues throughout life, termed secondary dentin (SD). The effect of attrition on SD formation was considered to be confined to the area subjacent to attrition facets. However, due to a lack of three-dimensional methodologies to demonstrate the structure of the SD, this association could not be determined. Therefore, in the current study, we aimed to explore the thickening pattern of the SD in relation to the amount of occlusal and interproximal attrition. A total of 30 premolars (50–60 years of age) with varying attrition rates were evaluated using micro-computerized tomography. The results revealed thickening of the SD below the cementoenamel junction (CEJ), mostly in the mesial and distal aspects of the root (p < 0.05). The pattern of thickening under the tooth cervix, rather than in proximity to attrition facets, was consistent regardless of the attrition level. The amount of SD thickening mildly correlated with occlusal attrition (r = 0.577, p < 0.05) and not with interproximal attrition. The thickening of the SD below the CEJ coincided with previous finite element models, suggesting that this area is mostly subjected to stress due to occlusal loadings. Therefore, we suggest that the SD formation might serve as a compensatory mechanism aimed to strengthen tooth structure against deflection caused by mechanical loading. Our study suggests that occlusal forces may play a significant role in SD formation.

Educational attainment and trajectories of cognitive decline during four decades-The Glostrup 1914 cohort.

BackgroundThe potential association between level of education and age-related cognitive decline remains an open question, partly because of a lack of studies including large subsamples with low education and follow-up intervals covering a substantial part of the adult lifespan.ObjectivesTo examine cognitive decline assessed by a comprehensive clinical test of intelligence over a 35-year period of follow-up from ages 50 to 85 and to analyze the effect of education on trajectories of cognitive decline, including the effects of selective attrition.MethodsA longitudinal cohort study with a 35-year follow-up of community dwelling members of the Glostrup 1914 cohort. The study sample comprised 697 men and women at the 50-year baseline assessment and additional participants recruited at later follow-ups. Verbal, Performance, and Full Scale IQs were assessed using the Wechsler Adult Intelligence Scale at ages 50, 60, 70, 80, and 85. To be able to track cognitive changes between successive WAIS assessments, all IQs were based on the Danish 50-year norms. Information on school education was self-reported. The association between education and cognitive decline over time was examined in growth curve models. Selective attrition was investigated in subsamples of participants who dropped out at early or later follow-ups.ResultsThe trajectories for Verbal, Performance, and Full Scale IQ showed higher initial cognitive performance, but also revealed steeper decline among participants with a formal school exam compared to participants without a formal exam. Verbal IQ showed the largest difference in level between the two educational groups, whereas the interaction between education and age was stronger for Performance IQ than for Verbal IQ. In spite of the difference in trajectories, higher mean IQ was observed among participants with a formal school exam compared to those without across all ages, including the 85-year follow-up.Further analyses revealed that early dropout was associated with steeper decline, but that this effect was unrelated to education.ConclusionComprehensive cognitive assessment over a 35-year period suggests that higher education is associated with steeper decline in IQ, but also higher mean IQ at all follow-ups. These findings are unlikely to reflect regression towards the mean, other characteristics of the employed test battery or associations between educational level and study dropout.

Effect of fiber attrition, particle characteristics and interfacial adhesion on the properties of PP/sugarcane bagasse fiber composites

PP/sugarcane bagasse fiber composites were prepared by injection molding from two fractions of fibers with different particle characteristics. The mechanical properties of the composites were characterized by tensile and impact measurements, while local deformation processes by acoustic emission testing and microscopy. The determination of fiber dimensions after processing showed that considerable attrition takes place during melt processing in both the length and the diameter of the fibers. Interfacial adhesion can be improved considerably by coupling. The strength of adhesion was estimated quantitatively and adhesion was ten times stronger (1600 mJ/m2) in the presence of the coupling agent than without it (140 mJ/m2) leading to larger composite strength in the former case. Local deformation processes also change with the strength of adhesion, debonding dominates without the coupling agent, while fiber fracture takes place at good adhesion. Fiber fracture consumes energy that leads to an increase in impact resistance. The size of the fibers must be reduced in order to achieve better properties, but the application of coupling cannot be avoided even in that case.

The Effects of Attrition on Grammatical Gender: A View from North American Icelandic

Heritage grammars have been argued to differ with respect to whether they are an instantiation of divergent attainment or attrition. Attrition and divergent attainment are not mutually exclusive and can even co-exist with respect to the same or different grammatical phenomena, but teasing these apart requires longitudinal studies or carefully selected cross-sectional data (Montrul, 2008; 2016; Polinsky, 2011). In this article we present data from a longitudinal corpus of letters written by a speaker of North American Icelandic over a span of seventy-two years. The earliest letters suggest that the writer acquired Icelandic consistent with the baseline. However, in the last thirty years of writing, non-target forms emerge in the corpus. Morphosyntax, notably grammatical gender and inflectional morphology, is the most affected domain of grammar. In this article we focus on the nature of the changes attested for grammatical gender across time. Our results show that gender assignment does not undergo a systematic re-analysis. However, the non-target gender agreement indicates the overuse of an agreement default, which may reflect a trend towards a systematic reduction of the gender agreement system.

Potential impact of midwives in preventing and reducing maternal and neonatal mortality and stillbirths: a Lives Saved Tool modelling study

SummaryBackgroundStrengthening the capacity of midwives to deliver high-quality maternal and newborn health services has been highlighted as a priority by global health organisations. To support low-income and middle-income countries (LMICs) in their decisions about investments in health, we aimed to estimate the potential impact of midwives on reducing maternal and neonatal deaths and stillbirths under several intervention coverage scenarios.MethodsFor this modelling study, we used the Lives Saved Tool to estimate the number of deaths that would be averted by 2035, if coverage of health interventions that can be delivered by professional midwives were scaled up in 88 countries that account for the vast majority of the world's maternal and neonatal deaths and stillbirths. We used four scenarios to assess the effects of increasing the coverage of midwife-delivered interventions by a modest amount (10% every 5 years), a substantial amount (25% every 5 years), and the amount needed to reach universal coverage of these interventions (ie, to 95%); and the effects of coverage attrition (a 2% decrease every 5 years). We grouped countries in three equal-sized groups according to their Human Development Index. Group A included the 30 countries with the lowest HDI, group B included 29 low-to-medium HDI countries, and group C included 29 medium-to-high HDI countries.FindingsWe estimated that, relative to current coverage, a substantial increase in coverage of midwife-delivered interventions could avert 41% of maternal deaths, 39% of neonatal deaths, and 26% of stillbirths, equating to 2·2 million deaths averted per year by 2035. Even a modest increase in coverage of midwife-delivered interventions could avert 22% of maternal deaths, 23% of neonatal deaths, and 14% of stillbirths, equating to 1·3 million deaths averted per year by 2035. Relative to current coverage, universal coverage of midwife-delivered interventions would avert 67% of maternal deaths, 64% of neonatal deaths, and 65% of stillbirths, allowing 4·3 million lives to be saved annually by 2035. These deaths averted would be particularly concentrated in the group B countries, which currently account for a large proportion of the world's population and have high mortality rates compared with group C.InterpretationMidwives can help to substantially reduce maternal and neonatal mortality and stillbirths in LMICs. However, to realise this potential, midwives need to have skills and competencies in line with recommendations from the International Confederation of Midwives, to be part of a team of sufficient size and skill, and to work in an enabling environment. Our study highlights the potential of midwives but there are many challenges to the achievement of this potential. If increased coverage of midwife-delivered interventions can be achieved, health systems will be better able to provide effective coverage of essential sexual, reproductive, maternal, newborn, and adolescent health interventions.FundingNew Venture Fund.

DIFFERENT MODERN TECHNIQUES USED IN CHURNA KALPANA: A REVIEW

To prepare any formulation in bulk quantity it needs a machine. The machines which manufacture the formulations in a bulk quantity will work on the basis of modern techniques. These techniques can be adopted to prepare different dosage forms through their method of preparations. Churna is also one among the different dosage forms which is having versatile usage and need to be prepared in bulk quantity. To achieve this, different modern methods like size reduction, size separation and mixing of powders and techniques viz. cutting, compression, impact, attrition and combined effect of impact and attrition are adopted, along with this sieving and mixing techniques are also adopted. To assure the quality of churna kalpana physico chemical analysis should be done like fineness of Particles, Presence of Heavy Metals, Test for microbial contamination etc.

Characteristics and predicted outcome of patients lost to follow-up after degenerative lumbar spine surgery

PurposeThe relatively large number of participants lost to follow-up (attrition) in spinal registers calls for studies that investigate the features of these individuals and their possible outcome. The aim was to explore the effect of attrition on patient-reported outcome in patients undergoing degenerative lumbar spine surgery. Three groups were studied: spinal stenosis (LSS), disc herniation (LDH) and degenerative disc disorder (DDD).MethodsPatients who underwent surgery for degenerative lumbar spine conditions during 2008–2012 according to registration in the Swespine national register were eligible for the study. Non-respondents were registered in Swespine prior to surgery, but not at follow-up. Swespine data were merged with hospital data from seven Swedish regions (65% of the population), Statistics Sweden, the National Patient Register and the Social Insurance Agency.Baseline characteristics of non-respondents were described and compared to those of the respondents. Coefficients from regression analyses on PROM values for respondents were used to estimate the levels of PROM values for non-respondents, assuming the same effects of baseline characteristics for the two subgroups. Regression analyses were then conducted to identify variables associated with non-response. The results from the regression analyses were used to predict outcomes for patients with the characteristics of a non-respondent. Primary outcome variable in LSS and LDH was Global Assessment for leg pain, and in DDD, Global Assessment for back pain.ResultsAge, sex, educational level, smoking, living alone, being born outside the EU, previous spine surgery and unexpected events before follow-up were factors that were significantly associated with non-response. Being born inside, the EU was important in all of the studied groups (LSS: OR 0.61 p = < 0.000; LDH: OR 0.68 p = 0.001; DDD: OR 0.58 p = 0.04). For spinal stenosis patients, an unexpected event appeared particularly important (OR 3.40, p = 0.000). The predicted outcome of non-respondents was significantly worse than for respondents (LSS: 75.4% successful outcome vs. 78.7%; LDH: 53.9% vs. 58.2%; DDD: 62.7% vs. 67.5%. P-value in all groups = < 0.000).ConclusionAttrition in Swespine cannot be ignored, as non-respondents were predicted to have worse outcome. The effect of attrition bias should always be considered when contemplating outcome recorded in a quality register with patients lost to follow-up.

Oxidation kinetics of biochar from woody and herbaceous biomass

The goal of this study was to determine oxidation kinetics for biochar produced from fast pyrolysis of various biomass feedstocks. In particular, the role of inherent ash content on the oxidation rate was evaluated. Thermogravimetric analysis (TGA) and fluidized bed combustion experiments were used to explore oxidation kinetics of six fast pyrolysis produced biochars with diverse ash content. Reaction rates varied by a factor of three under chemical kinetic-limited conditions, demonstrating inorganic content impacts oxidation rate. Chemical kinetic rate coefficients were proposed as a function of compositional parameters to determine overall fit and impact. Potassium content was found to have a positive correlation, best describing the differences in the oxidation kinetic rate coefficients. Additionally, feedstocks were subjected to a 1 M HCl acid wash mitigating the catalytic activity of the metals. Acid washed biochars had lower oxidation kinetic rates compared to their unwashed counterparts, indicating the removal of catalytically active metals reduced oxidation rate. Gas composition (CO/CO2) was measured during fluidized bed experiments for both acid-washed and unwashed biochars, which varied between the six biochars. Formation of CO2 was greatly affected by catalytic metals, finding potassium content to correlate well with a higher percentage of CO2 formation as compared to CO. Comparison of oxidation rates were made between the two experimental apparatuses to measure the effect of attrition on biochar oxidation.

Risk Attitudes, Sample Selection, and Attrition in a Longitudinal Field Experiment

We evaluate the temporal stability of risk preferences using a remarkable data set that combines sociodemographic information from the Danish Civil Registry with information on risk attitudes from a longitudinal field experiment. Our econometric model accounts for endogenous sample selection and attrition processes that may confound inferences about temporal stability. Our experimental design builds in randomization on the incentives for participation that facilitates empirical identification of the model. In general, we find evidence consistent with temporal stability after correcting for the effects of selection and attrition. When neglected, these effects change our inferences in an economically and statistically significant manner.

Durability Performance of Concrete (M-45) Fine Aggregate Partially Replaced with Crushed Waste Glass

Durability of concrete is as the ability to resist weathering action, chemical attack, and abrasion while giving the desired engineering properties. Concrete require different degrees of durability depending on the exposure environmental conditions. The retrogression of concrete structures is due to effect of attrition of reinforcing bars which is occurred due to the chloride incursion.so it is necessary to study the concrete durability nature before making its usage in present construction. The present research is focused on studying the effect of using sustainable material in concrete preparation. To know the effective usage of crushed waste glass in concrete and significance in Durability properties for different replacements was studied .The present research work was done using materials like cement, Fine aggregate, coarse aggregate, waste crushed glass, super plasticizer in order to know that at which combination of mix there will be optimum effect on properties of concrete. In this research Waste crushed glass was used as fractions of 10%,20%,30% and 40% by weight of crushed glass used. The durability tests to test resistance against acid environment chloride penetration and abrasion resistance tests are performed. The optimum value of acid resistance was observed when fine aggregate was replaced with 30% of fine aggregate with crushed waste glass, less abrasion loss at 30% replacement and chloride penetration also effective at 30% replacement.

General concepts in biostatistics and clinical epidemiology: Experimental studies with randomized clinical trial design.

In experimental studies, researchers apply an intervention to a group of study participants and analyze the effects over a future or prospective timeline. The prospective nature of these types of studies allows for the determination of causal relationships, but the interventions they are based on require rigorous bioethical evaluation, approval from an ethics committee, and registration of the study protocol prior to implementation. Experimental research includes clinical and preclinical testing of a novel intervention or therapy at different phases of development. The main objective of clinical trials is to evaluate an interventions efficacy and safety. Conventional clinical trials are blinded, randomized, and controlled, meaning that participants are randomly assigned to either the study intervention group or a comparator (a control group exposed to a placebo intervention or another non-placebo or active interventionor not exposed to any intervention) to reduce selection and confounding biases, and researchers are also unaware of the type of intervention being applied. Intention-to-treat analysis (inclusion of all originally randomized subjects) should be done to avoid the effects of attrition (dropout) and crossover (variance in the exposure or treatment over time). A quasi-experimental design and external controls may also be used. Metrics used to measure the magnitude of effects include relative risk, absolute and relative risk reductions, and numbers needed to treat and harm. Confounding factors are controlled by randomization. Other types of bias to consider are selection, performance, detection, and reporting. This review is the fifth of a methodological series on general concepts in biostatistics and clinical epidemiology developed by the Chair of Scientific Research Methodology at the School of Medicine, University of Valparaíso, Chile. It describes general theoretical concepts related to randomized clinical trials and other experimental studies in humans, including fundamental elements, historical development, bioethical issues, structure, design, association measures, biases, and reporting guidelines. Factors that should be considered in the execution and evaluation of a clinical trial are also covered.

Durability Performance of Concrete (M-45) Fine Aggregate Partially Replaced with Crushed Waste Glass

Durability of concrete is as the ability to resist weathering action, chemical attack, and abrasion while giving the desired engineering properties. Concrete require different degrees of durability depending on the exposure environmental conditions. The retrogression of concrete structures is due to effect of attrition of reinforcing bars which is occurred due to the chloride incursion.so it is necessary to study the concrete durability nature before making its usage in present construction. The present research is focused on studying the effect of using sustainable material in concrete preparation. To know the effective usage of crushed waste glass in concrete and significance in Durability properties for different replacements was studied .The present research work was done using materials like cement, Fine aggregate, coarse aggregate, waste crushed glass, super plasticizer in order to know that at which combination of mix there will be optimum effect on properties of concrete. In this research Waste crushed glass was used as fractions of 10%,20%,30% and 40% by weight of crushed glass used. The durability tests to test resistance against acid environment chloride penetration and abrasion resistance tests are performed. The optimum value of acid resistance was observed when fine aggregate was replaced with 30% of fine aggregate with crushed waste glass, less abrasion loss at 30% replacement and chloride penetration also effective at 30% replacement.

Effect of surface attrition on hardness on the hardness and wear properties of 304 stainless steels

The occurrence of wear in austenitic stainless steel is inevitably unavoidable due to the presence of high chromium content and other alloying elements that hinder the implementation of surface treatment process. This process is usually use to improve the hardness and wear properties of steels and alloys by diffusing hard protected layer on the surface of the material. This paper investigates the effect of surface attrition on the hardness and wear properties of paste boronized 304 stainless steel. Surface attrition treatment was applied onto the surface of 304 stainless steel before paste boronizing was conducted at temperature of 850°C for 8 hours holding times. The microstructure of the boronized samples before and after surface attrition treatment was then observed and recorded in order to compare the phase constituent and boride layer thickness. The hardness of each phases was then evaluated using Vickers microhardness test and the wear resistance test of both paste boronized sample and surface attrited samples after boronizing was performed using pin on disk test. The microstructure results show that there are presences of both FeB and Fe2B phases on the surface of Pa-B850 and Pa-SB with boride layer thickness improvement of 3 times compared to untreated samples. This lead to enhancement of both hardness and wear resistance of the paste boronized samples due to better protection on the surface of the 304 stainless steel. The improvement of wear and hardness properties of 304 stainless steel could introduce new application that could be exposed to environment containing friction and wear.

The cluster randomized crossover trial: The effects of attrition in the AB/BA design and how to account for it in sample size calculations.

Background/Aims:This article studies the effect of attrition in the cluster randomized crossover trial. The focus is on the two-treatment two-period AB/BA design where attrition occurs during the washout period. Attrition may occur at either the subject level or the cluster level. In the latter case, clusters drop out entirely and provide no measurements in the second period. Subject attrition can only occur in the cohort design, where each subject receives both treatments. Cluster attrition can also occur in the cross-sectional design, where different subjects are measured in the two time periods. Furthermore, this article explores two different strategies to account for potential levels of attrition: increasing sample size and replacing those subjects who drop out by others.Methods:The statistical model that takes into account the nesting of subjects within clusters, and the nesting of repeated measurements within subjects is presented. The effect of attrition is evaluated on the basis of the efficiency of the treatment effect estimator. Matrix algebra is used to derive the relation between efficiency, the degree of attrition, cluster size and the intraclass correlations: the within-cluster within-period correlation, the within-cluster between-period correlation and (in the case of a cohort design) the within-subject correlation. The methodology is implemented in two Shiny Apps.Results:Attrition in a cluster randomized crossover trial implies a loss of efficiency. Efficiency decreases with an increase of the attrition rate. The loss of efficiency due to attrition of subjects in a cohort design is largest for small number of subjects per cluster-period, but it may be repaired to a large degree by increasing the number of subjects per cluster-period or by replacing those subjects who drop out by others. Attrition of clusters results in a larger loss of efficiency, but this loss does not depend on the number of subjects per cluster-period. Repairing for this loss requires a large increase in the number of subjects per cluster-period. The methodology of this article is illustrated by an example on the effect of lavender scent on dental patients’ anxiety.Conclusion:This article provides the methodology of exploring the effect of attrition in cluster randomized crossover trials, and to repair for attrition. As such, it helps researchers plan their trial in an appropriate way and avoid underpowered trials. To use the methodology, prior estimates of the degree of attrition and intraclass correlation coefficients are needed. It is advocated that researchers clearly report the estimates of these quantities to help facilitate planning future trials.

Drafting the Dutch: Selection Biases in Dutch Conscript Records in the Second Half of the Nineteenth Century

ABSTRACTConscription records are considered to be the best sources for studying heights over cohorts. This article discusses the various steps and selection mechanisms involved in the conscription system of the Netherlands, which was more or less similar to the systems found in other European countries. Starting with a birth cohort of 4,436 boys, we run a series of regressions on the likelihood to be registered at all and to have one’s height recorded. We discuss the effects of cohort attrition through mortality and migration, and explore familial, social, and religious reasons for evading registration and (medical) examination. We find various kinds of selections, but their effects on the distribution and averages of heights are limited. Thus, heights culled from conscripts records are indeed an excellent indicator of a cohort’s biological standard of living. However, researchers focusing on social variation in height need to be aware of the unequal opportunities to evade registration and measurement.

Effect of surface mechanical attrition on microstructure and mechanical properties of hypoeuctectoid steel

Effect of ultra-fine structure obtained by surface mechanical attrition treatment(SMAT) on microstructure, yield strength (YS), ultimate tensile strength (UTS) and microhardness of hypoeuctectoid steel have been studied in this paper. Surface alteration has been obtained by vibratory SMAT equipment with particular parameters for similar class of material. The SMAT has been carried out for different time periods such as 10, 20, 30 min. The pearlite and ferrite geometry present has been found intermixed after SMAT process. The microstructure shows a composite structure consisting of fiber/angular cementite particulates dispersed in a ferrite matrix. Thus, these structure obtained at 30 min of SMAT has significantly affected the mechanical properties. The SMAT affected layer has found to be 300μm which shows an increased Young’s modulus from 140 GPa to 246 GPa. The yield stress (YS) and ultimate tensile strength (UTS) has been increased about 6% and 22% , respectively. The surface microhardness of the material has been changed from 226±5 HV0.3 to 405±7 HV0.3 by SMAT, which is attributed to the grain refinement and dispersion of fine carbide particles within the matrix.

The Effects of Reverse Causality and Selective Attrition on the Relationship Between Body Mass Index and Mortality in Postmenopausal Women.

Concerns about reverse causality and selection bias complicate the interpretation of studies of body mass index (BMI, calculated as weight (kg)/height (m)2) and mortality in older adults. The objective of this study was to investigate methodological explanations for the apparent attenuation of obesity-related risks in older adults. We used data from 68,132 participants in the Women's Health Initiative (WHI) clinical trial for this analysis. All of the participants were postmenopausal women aged 50-79 years at baseline (1993-1998). To examine reverse causality and selective attrition, we compared rate ratios from inverse probability of treatment- and censoring-weighted Poisson marginal structural models with results from an unweighted adjusted Poisson regression model. The estimated mortality rate ratios and 95% confidence intervals for BMIs of 30.0-34.9, 35.0-39.9 and ≥40.0 were 0.86 (95% confidence interval (CI): 0.77, 0.96), 0.85 (95% CI: 0.72, 0.99), and 0.88 (95% CI: 0.72, 1.07), respectively, in the unweighted model. The corresponding mortality rate ratios were 0.96 (95% CI: 0.86, 1.07), 1.12 (95% CI: 0.97, 1.29), and 1.31 95% CI: (1.08, 1.57), respectively, in the marginal structural model. Results from the inverse probability of treatment- and censoring-weighted marginal structural model were attenuated in low BMI categories and increased in high BMI categories. The results demonstrate the importance of accounting for reverse causality and selective attrition in studies of older adults.