Search results for: stress life approach

Authors: Kamel Hachour, Lydia Sadeg, Djamel Sersab, Tassadit Bellahcen

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The hydrostatic stress is, for polymers, a significant parameter which affects the yield behavior of these materials. In this work, we investigate the influence of this parameter on yield behavior of the high density polyethylene (hdpe). Some tests on specimens with diverse geometries are described in this paper. Uniaxial tests: tensile on notched round bar specimens with different curvature radii, compression on cylindrical specimens and simple shear on parallelepiped specimens were performed. Biaxial tests with various combinations of tensile/compressive and shear loading on butterfly specimens were also realized in order to determine the hydrostatic stress for different states of solicitation. The experimental results show that the yield stress is very affected by the hydrostatic stress developed in the material during solicitations.

Keywords: biaxial tests, hdpe, Hydrostatic stress, yield behavior

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Authors: Masoud Rafiee

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To study the quality response of forage to chickpea-barley mixed cropping under drought stress and vermicompost consumption, an experiment was carried out under well watered and %70 water requirement (stress condition) in RCBD as split plot with four replications in temperate condition of Khorramabad in 2013. Chickpea-barley mix cropping (%100 chickpea, %75:25 chickpea:barley, %50:50 chickpea:barley, %25:75 chickpea:barley, and %100 barley) was studied. Results showed that wet and dry forage yield were significantly affected by environment and decreased in stress condition. Also, crude protein content decreased from %26.2 in well watered to %17.3 in stress condition.

Keywords: crude protein, wet forage yield, dry forage yield, water stress condition, well watered

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Authors: Seung-Un Chae, Heung-Yul Kim, Sa-Kil Kim

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This paper presents the findings of preliminary study on human control performance in case of fire. The relationship between human control and human decision is studied in decision processes and stress model of human in a fire. Human behavior aspects involved in the decision process during a fire incident. The decision processes appear that six of individual perceptual processes: recognition, validation, definition, evaluation, commitment, and reassessment. Then, human may be stressed in order to get an optimal decision for their activity. This paper explores problems in human control processes and stresses in a catastrophic situation. Thus, the future approach will be concerned to reduce stresses and ambiguous irrelevant information.

Keywords: human reliability, decision processes, stress model, fire

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Authors: Agnieszka Rolinska, Marta Makara-Studzinska

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Introduction: In recent years, there has been an intensive development of research into the physiological relationships between the experienced stress and obesity. Moreover, strong chronic stress leads to the disorganization of a person’s activeness on various levels of functioning, including the behavioral and cognitive sphere (also in one’s diet). Aim: The present work addresses the following research questions: Is there a relationship between an increase in stress related to the disease and the need for the cyclicality of diabetologic education in gestational diabetes? Are there any differences in terms of the experienced stress during the last three months of pregnancy in women with gestational diabetes and in normal pregnancy between the patients with normal weight gains and those with abnormal weight gains? Are there any differences in terms of stress coping styles in women with gestational diabetes and in normal pregnancy between the patients with normal weight gains and those with abnormal weight gains? Method: The study involved pregnant women with gestational diabetes (treated with diet, without insulin therapy) and in normal pregnancy – 206 women in total. The following psychometric tools were employed: Perceived Stress Scale (PSS; Cohen, Kamarck, Mermelstein), Coping Inventory for Stressful Situations (CISS; Endler, Parker) and authors’ own questionnaire. Gestational diabetes mellitus was diagnosed on the basis of the results of fasting oral glucose tolerance test (75 g OGTT). Body weight measurements were confirmed in a diagnostic interview, taking into account medical data. Regularities in weight gains in pregnancy were determined according to the recommendations of the Polish Gynecological Society and American norms determined by the Institute of Medicine (IOM). Conclusions: An increase in stress related to the disease varies in patients with differing requirements for the cyclical nature of diabetologic education (i.e. education which is systematically repeated). There are no differences in terms of recently experienced stress and stress coping styles between women with gestational diabetes and those in normal pregnancy. There is a relationship between weight gains in pregnancy and the stress experienced in life as well as stress coping styles – both in pregnancy complicated by diabetes and in physiological pregnancy. In the discussion of the obtained results, the authors refer to scientific reports from English-language magazines of international range.

Keywords: diabetologic education, gestational diabetes, stress, weight gain in pregnancy

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Authors: M. Münch, R. Brandt

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Martensitic steels with an ultimate tensile strength beyond 2000 MPa are applied in the powertrain of vehicles due to their excellent fatigue strength and high creep resistance. However, the creep controlling mechanism in martensitic steels at ambient temperatures up to 423 K is not evident. The purpose of this study is to review the low temperature creep (LTC) behavior of martensitic steels at temperatures from 363 K to 523 K. Thus, the validity of a logarithmic creep law is reviewed and the stress and temperature dependence of the creep parameters α and β are revealed. Furthermore, creep tests are carried out, which include stepped changes in temperature or stress, respectively. On one hand, the change of the creep rate due to a temperature step provides information on the magnitude of the activation energy of the LTC controlling mechanism and on the other hand, the stress step approach provides information on the magnitude of the activation volume. The magnitude, the temperature dependency, and the stress dependency of both material specific activation parameters may deliver a significant contribution to the disclosure of the nature of the LTC rate controlling mechanism.

Keywords: activation parameters, creep mechanisms, high strength steels, low temperature creep

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Authors: Saeed Rauf

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Purpose: Drought stress is a major production constraint in sunflowers and causes yield losses under tropical and subtropical environments having high evapo-tranpirational losses. Given the consequences, three trials were designed to evaluate drought-resistant sunflower hybrids. Research Methods: Field trials were conducted under a split-plot arrangement with 17 hybrids and two contrasting regimes at Sargodha, Pakistan and 7 hybrids at Karj, Iran. Water stress condition was simulated by holding water in a stress regime. Hybrids were also screened against five levels of osmotic-ally induced stress, i.e. 0-15%, under a completely randomized design with 3 replications. Findings: Hybrids H1 (C.112.× RH.344) and H3 (C.112.× RSIN.82) showed the highest seed yield ha-1 and early flowering at Karj Iran. Commercial hybrid had the highest CTD (18.2°C) followed by C112 × RH.344 (17.29 °C). Hybrid C.250 × R.SIN.82 had the highest seed yield (m-2), followed by C.112 × RH.365 and C.124 × RSIN.82 under both stress and non-stress regimes at Sargodha, Pakistan. Seedling trial results showed that 6 hybrids only germinated in 5 and 7.5% PEG-induced osmotic stress, respectively. H1 (C.112 × RH.344) and H2 (C.112 × RH.347) had the highest germination% at 5% and 7.5% osmotic stress (OS). Seedling vigor index (SVI) was the highest in H1 (C.112 × RH.344) hybrids at 5% OS, H2 had the highest SVI under 7.5% OS, followed by H3 (C112 × RH344) and H4 (C116 × RH344). Originality/Value: In view of above results, it was concluded that hybrid combination H1 had the highest seed yield under stress conditions in both environments. High seed yield may be due to its better germination and vigor index under stress conditions.

Keywords: climate change, CTD, genetic variability, osmotic stress

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Authors: Potaliya Pushpa, Kataria Sushma, D. S. Chowdhary, Dadhich Abhilasha

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Introduction: Stress is a nonspecific response of the body to a stressor or triggering stimulus. Chronic stress exposure contributes to various remarkable alterations o growth and development. Collective effects of stressors lead to several changes which are physical, physiological and behavioral in nature. Objective: To understand on an animal model how various chronic stress affect the somatic body growth as it can be useful for effective stress treatment and prevention of stress related illnesses. Material and Method: By selective fostering only male pup colonies were made and 102 male albino rats were studied. They were divided two groups as Control and Stressed. The experimental groups were exposed to four major types of stress as maternal deprivation, Restraint stress, electric foot shock and noise stress for affecting emotional, physical and physiological activities. Exposure was from birth to 17 week of life. Roentgenographs were taken in two planes as Dorso-ventral and Lateral and then measured for each rat. Various parameters were observed at specific intervals. Parameters recorded were Body weight and for linear growth it was summation of Cranial length, Head rump length and tail length. Behavior changes were also observed. Result: Multiple chronic stresses resulted in loss of approx. 25% of mean body weight. Maximal difference was found on 119th day (i.e. 87.81 gm) between the control and stressed group. Linear growth showed retardation which was found to be significant in stressed group on statistical analysis. Cranial Length and Head-rump Length showed maximum difference after maternal deprivation stress. After maternal deprivation (Day 21) and electric foot shock (Day 101) maximum difference i.e. 0.39 cm and 0.47 cm were found in cranial length of two groups. Electric foot shock had considerable impact on tail length. Noise Stress affected moreover behavior as compact to physical growth. Conclusion: Collective study showed that chronic stress not only resulted in reduced body weight in albino rats but also total linear size of rat thus affecting whole growth and development.

Keywords: stress, microscopic anatomy, macroscopic anatomy, chronic multiple stress, birth

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Authors: Vahid Rashedi, Banafsheh Ebrahimi, Mahtab Sharif Mohseni, Mohammadali Hosseini

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Introduction: One of the metrics used to evaluate health status is life expectancy. This index alters as people age as a result of several events, illnesses, stress, and anxiety. One of the issues that might develop into a lethal phobia is death anxiety. This study looked at older persons in Tehran, Iran, to see if there was any correlation between life expectancy and fear of dying. Methods: Cluster random sampling was used to select 208 older persons (age 60) who had been sent to adult daycare facilities in Tehran for this correlational descriptive study. A demographic questionnaire, Temper's death anxiety scale, and Snyder's life expectancy scale were used to gather the data. Statistical Package for the Social Sciences softwear version 22 was used to conduct the data analysis. Results: The average age of the senior citizens was 66.60 (6.58) years. With a mean life expectancy of 24.94, it was discovered that the average death anxiety was 12.21. Additionally, Pearson's correlation coefficient demonstrated a bad correlation between fear of dying and life expectancy. Age, residential status, and death fear were the three primary predictors of a decline in life expectancy, according to multiple regression analysis. Conclusion: The findings suggest that there is a link between death fear and a lower life expectancy, which calls for the use of appropriate strategies to increase older individuals' life expectancies as well as the teaching of anxiety coping mechanisms.

Keywords: aged, frailty, death, anxiety, life

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Authors: Nandita Chaube, S. S. Nathawat

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Sleep paralysis is a state of sleep disturbance in which people experience hypnogogic or hypnopompic hallucinations marked by an inability to move their bodies or speak out while reporting the consciousness about their surroundings. Philosophical explanation of sleep paralysis has been quoted in the ancient texts in terms of incubus and succubus. However, pathologically, it has been linked to several disorders including narcolepsy, migraines, anxiety disorders, and obstructive sleep apnea but it can also occur in isolation. Some other significant factors may include perceived stress, spiritual and paranormal beliefs, etc. Hence, a qualitative analysis of five such cases reporting symptoms of sleep disturbances with the criterion of sleep paralysis has been reported here. The study considered various psychological factors like stressful life events, feelings of inadequacy, spirituality, and paranormal beliefs. Results disclosed that four of the five cases were inclined towards the paranormal beliefs and the entire sample indicated a noticeably augmented level of spirituality and feelings of inadequacy. Furthermore, three cases reported experiencing greater stress following life events. Among other factors, all the cases were characterized with sleeping in the supine position, sleeping alone, an experience of fear, a sense of pressure on their chest, a presence of someone in the room and increased level of feelings of inadequacy.

Keywords: genesis, inadequacy, paranormal, sleep-paralysis, spiritual, stress

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Authors: Jia-Yu Wu, Chih-Han Chang, Shu-Fen Chuang, Rong-Yang Lai

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Objective: This study was to examine the stress distribution of tooth with different class V restorations under different loading situations and geometry by 3D finite element (FE) analysis. `Methods: A series of FE models of mandibular premolars containing class V cavities were constructed using micro-CT. The class V cavities were assigned as the combinations of different cavity depths x occlusal -gingival heights: 1x2, 1x4, 2x2, and 2x4 mm. Three alveolar bone loss conditions were examined: 0, 1, and 2 mm. 200 N force was exerted on the buccal cusp tip under various directions (vertical, V; obliquely 30° angled, O; oblique and parallel the individual occlusal cavity wall, P). A 3-D FE analysis was performed and the von-Mises stress was used to summarize the data of stress distribution and maximum stress. Results: The maximal stress did not vary in different alveolar bone heights. For each geometry, the maximal stress was found at bilateral corners of the cavity. The peak stress of restorations was significantly higher under load P compared to those under loads V and O while the latter two were similar. 2x2mm cavity exhibited significantly increased (2.88 fold) stress under load P compared to that under load V, followed by 1x2mm (2.11 fold), 2x4mm (1.98 fold) and 1x4mm (1.1fold). Conclusion: Load direction causes the greatest impact on the results of stress, while the effect of alveolar bone loss is minor. Load direction parallel to the cavity wall may enhance the stress concentration especially in deep and narrow class cavities.

Keywords: class v restoration, finite element analysis, loading situation, stress

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Authors: Retty Ratnawati, Santi Sri Wulandari, Tulus Sabrina

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Feminine and masculine gender role stress could occur in some work situation. Being manager in health services that is known to be more women’ role in Indonesia, has expected to have feminine stereotype role. In the communities, this has been done in the program kesejahteraan keluarga (welfare family program) since the 1970s, for example through family planning program. The aim of the study was to explore the experience of being a motherhood managerial in health services. Our auto ethnographic study has revealed that motherhood managerial, even though running by a woman, could have some stress conditions whether she has realized or has not. The challenge would occur when the manager did not realize that she needed the eustress. The autonomy concept for a woman to be a manager could be a complex cycle that needs open communication continually and understanding the four elements surround her life. In conclusion, there is a demand to have the eustress when the manager does not realize that she has to be an autonomy person. However, it does not need eustress when the manager understands about how to deal with the complex cycle of being autonomy.

Keywords: motherhood managerial, eustress, feminine gender role stress, masculine gender role stress, autonomy concept in women

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Authors: Aderet M. Pantierer, Shmuel Pantierer, Raphael Cordina, Yougashwar Budhoo

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Stress concentration occurs when there is an abrupt change in geometry, a mechanical part under loading. These changes in geometry can include holes, notches, or cracks within the component. The modifications create larger stress within the part. This maximum stress is difficult to determine, as it is directly at the point of the minimum area. Strain gauges have yet to be developed to analyze stresses at such minute areas. Therefore, a stress concentration factor must be utilized. The stress concentration factor is a dimensionless parameter calculated solely on the geometry of a part. The factor is multiplied by the nominal, or average, stress of the component, which can be found analytically or experimentally. Stress concentration graphs exist for common loading conditions and geometrical configurations to aid in the determination of the maximum stress a part can withstand. These graphs were developed from historical data yielded from experimentation. This project seeks to verify a stress concentration graph for combined loading conditions. The aforementioned graph was developed using CATIA Finite Element Analysis software. The results of this analysis will be validated through further testing. The 3D modeled parts will be subjected to further finite element analysis using Patran-Nastran software. The finite element models will then be verified by testing physical specimen using a tensile testing machine. Once the data is validated, the unique stress concentration graph will be submitted for publication so it can aid engineers in future projects.

Keywords: stress concentration, finite element analysis, finite element models, combined loading

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Authors: P. Selva, B. Lorraina, J. Alexis, A. Seror, A. Longuet, C. Mary, F. Denard

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Over the past four decades, the fatigue behavior of nickel-based alloys has been widely studied. However, in recent years, significant advances in the fabrication process leading to grain size reduction have been made in order to improve fatigue properties of aircraft turbine discs. Indeed, a change in particle size affects the initiation mode of fatigue cracks as well as the fatigue life of the material. The present study aims to investigate the fatigue behavior of a newly developed nickel-based superalloy under biaxial-planar loading. Low Cycle Fatigue (LCF) tests are performed at different stress ratios so as to study the influence of the multiaxial stress state on the fatigue life of the material. Full-field displacement and strain measurements as well as crack initiation detection are obtained using Digital Image Correlation (DIC) techniques. The aim of this presentation is first to provide an in-depth description of both the experimental set-up and protocol: the multiaxial testing machine, the specific design of the cruciform specimen and performances of the DIC code are introduced. Second, results for sixteen specimens related to different load ratios are presented. Crack detection, strain amplitude and number of cycles to crack initiation vs. triaxial stress ratio for each loading case are given. Third, from fractographic investigations by scanning electron microscopy it is found that the mechanism of fatigue crack initiation does not depend on the triaxial stress ratio and that most fatigue cracks initiate from subsurface carbides.

Keywords: cruciform specimen, multiaxial fatigue, nickel-based superalloy

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Authors: Asnakech Zekiwos

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Background: Stress in nursing refers to the reactions nurses experience when faced with work demands that exceed their knowledge, skills, or ability to cope. Nursing, as a profession, is particularly susceptible to work-related stress. Methods: A cross-sectional study was conducted among 405 randomly selected nurses working in Hadiya Zone Public Hospitals from March 1 to 30, 2023. Data were collected using a pre-tested self-administered questionnaire. The data were entered using Epi-data version 3.1 and analyzed using SPSS version 20.0. Multivariable logistic regression analysis was performed to identify factors associated with the level of work stress. Variables with a p-value <0.05 were considered statistically significant. Results: In this study, 56% (95% CI 50.9-61.2) of the participants reported being stressed in their work. Several factors were found to be associated with work stress, including being female (AOR=1.94, 95% CI 1.19-3.16), rotating shifts (AOR=2.06, 95% CI 1.31-3.25), working in the intensive care unit (AOR=3.42, 95% CI 1.20-9.73), and having post-basic training (AOR=0.55, 95% CI 0.34-0.92). Conclusion: The study revealed a high level of work stress among nurses in the study area. The zonal health unit takes measures to address work stress by providing job orientation during the hiring process, rotation, and on-the-job training to help nurses cope with and manage stressful events. Stress in public hospitals and among nurses is an important issue that needs attention.

Keywords: stress, nurses, public hospitals, expanded stress scale

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Authors: Mantai Chen, Johnny Ching Ming Ho

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The stress-strain relationship of concrete under flexure is one of the essential parameters in assessing ultimate flexural strength capacity of RC beams. Currently, the concrete stress-strain curve in flexure is obtained by incorporating a constant scale-down factor of 0.85 in the uniaxial stress-strain curve. However, it was revealed that strain gradient would improve the maximum concrete stress under flexure and concrete stress-strain curve is strain gradient dependent. Based on the strain-gradient-dependent concrete stress-strain curve, the investigation of the combined effects of strain gradient and concrete strength on flexural strength of RC beams was extended to high strength concrete up to 100 MPa by theoretical analysis. As an extension and application of the authors’ previous study, a new flexural strength design method incorporating the combined effects of strain gradient and concrete strength is developed. A set of equivalent rectangular concrete stress block parameters is proposed and applied to produce a series of design charts showing that the flexural strength of RC beams are improved with strain gradient effect considered.

Keywords: beams, equivalent concrete stress block, flexural strength, strain gradient

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Authors: Tejeet Singh, Ishvneet Singh, Vinay Gupta

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The present study focussed on carrying out the creep analysis in an isotropic thick-walled composite cylindrical pressure vessel composed of aluminium matrix reinforced with silicon-carbide in particulate form. The creep behaviour of the composite material has been described by the threshold stress based creep law. The value of stress exponent appearing in the creep law was selected as 3, 5 and 8. The constitutive equations were developed using well known von-Mises yield criteria. Models were developed to find out the distributions of creep stresses and strain rate in thick-walled composite cylindrical pressure vessels under internal pressure. In order to obtain the stress distributions in the cylinder, the equilibrium equation of the continuum mechanics and the constitutive equations are solved together. It was observed that the radial stress, tangential stress and axial stress increases along with the radial distance. The cross-over was also obtained almost at the middle region of cylindrical vessel for tangential and axial stress for different values of stress exponent. The strain rates were also decreasing in nature along the entire radius.

Keywords: creep, composite, cylindrical vessel, internal pressure

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Authors: Namhun Lee, Seong Jin Kim

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The construction industry represents one of the largest industries in the United States, yet it continues to face several occupational health and safety challenges. Many workers on construction sites are suffering from extended exposure to stressful situations such as poor and hazardous work environments and task complexity. Stress can be commonly defined as a feeling of emotional or physical tension, which can easily impact construction safety and result in a higher rate of job-related injuries in the construction industry. Physiological signals transmitted from wearable biosensors can be used to detect excessive stress. Therefore, workers’ stress should be detected and mitigated to prevent any type of serious incident or accident proactively. By doing this, construction productivity, as well as job satisfaction, would also be improved in the construction industry. To establish a foundation in this field of research, a conceptual framework for using wearable technology for construction safety has been developed for continuous and automatic monitoring of worker’s stress. The conceptual framework will serve as a foothold in future studies on the application of wearable technology for construction safety.

Keywords: construction safety, occupational stress, stress monitoring, wearable biosensors

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Authors: K. M. Ngbea, F. Ugwu, J. M. Uwouku, P. Atsehe, A. Ucho, P. N. Achakpa-Ikyo, P. Azende

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This study examined occupational stress, perceived fairness and organizational citizenship behavior among bank workers. The participants were 198 (118) males and (80) female's bank employees from selected banks within Makurdi metropolis and questionnaire were used for data collection. Three hypotheses were tested and it was found that employees with high perception of occupational stress differ significantly from their counterparts at perceived fairness also influenced organizational citizenship behavior.On the other hand, there is no interaction effect of occupational stress and perceived fairness on organizational citizenship behavior. The implication of findings, limitations, recommendations and conclusions were discussed.

Keywords: occupational stress, perceived fairness, organizational citizenship, behavior

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Authors: Zelalem Markos Borko

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Work-related stress is a reaction that occurs when the work weight progress toward becoming excessive. Therefore, unless properly managed, stress leads to high employee turnover, decreased performance, illness and absenteeism. Yet, little has been addressed regarding work-related stress and its predictors in the study area. Therefore, the objective of this study was to assess stress prevalence and its predictors in the study area. To that effect, a cross-sectional study design was conducted on 281 employees from the Ethiopian Federal Bureau of Investigation by using stratified random sampling techniques. Survey questionnaire scales were employed to collect data. Data were analyzed by percentage, Pearson correlation coefficients, simple linear regression, multiple linear regressions, independent t-test and one-way ANOVA statistical techniques. In the present study13.9% of participants faced high stress, whereas 13.5% of participants faced low stress and the rest 72.6% of officers experienced moderate stress. There is no significant group difference among workers due to age, gender, marital status, educational level, years of service and police rank. This study concludes that factors such as role conflict, performance over-utilization, role ambiguity, and qualitative and quantitative role overload together predict 39.6% of work-related stress. This indicates that 60.4% of the variation in stress is explained by other factors, so other additional research should be done to identify additional factors predicting stress. To prevent occupational stress among police, the Ethiopian Federal Bureau of Investigation should develop strategies based on factors that will help to develop stress reduction management.

Keywords: work-related stress, Ethiopian federal bureau of investigation, predictors, Addis Ababa

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Authors: Adnan Zaid

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Stress corrosion cracking (SCC) may be defined as a degradation of the mechanical properties of a material under the combined action of a tensile stress and corrosive environment of the susceptible material. It is a harmful phenomenon which might cause catastrophic fracture without a sign of prior warning. In this paper, the stress corrosion cracking, SCC, process, the parameters affecting it, and the different damages caused by it are given and discussed. Utilization of shot peening as a mean of enhancing the resistance of materials to SCC is given and discussed. Finally, a method for improving materials resistance to SCC by grain refining its structure by some refining elements prior to usage is suggested.

Keywords: stress corrosion cracking, parameters, damages, treatment methods

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Authors: Farshid Marbouti, Jale Ulas, Julia Thompson

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The main sources of stress among college students are: changes in sleeping and eating habits, undertaking new responsibilities, and financial difficulties as the most common sources of stress, exams, meeting new people, career decisions, fear of failure, and pressure from parents, transition to university especially if it requires leaving home, working with people that they do not know, trouble with parents, and relationship with the opposite sex. The students use a variety of stress coping strategies, including talking to family and friends, leisure activities and exercising. The Yerkes–Dodson law indicates while a moderate amount of stress may be beneficial for performance, too high stress will result in weak performance. In other words, if students are too stressed, they are likely to have low academic performance. In a preliminary study conducted in 2017 with engineering students enrolled in three high failure rate classes, the majority of the students stated that they have high levels of stress mainly for academic, financial, or family-related reasons. As the second stage of the study, the main purpose of this research is to investigate the students’ level of stress, sources of stress, their relationship with student demographic background, students’ coping strategies, and academic performance. A device is being developed to gather data from students breathing patterns and measure their stress levels. In addition, all participants are asked to fill out a survey. The survey under development has the following categories: exam stressor, study-related stressors, financial pressures, transition to university, family-related stress, student response to stress, and stress management. After the data collection, Structural Equation Modeling (SEM) analysis will be conducted in order to identify the relationship among students’ level of stress, coping strategies, and academic performance.

Keywords: college student stress, coping strategies, academic performance, measuring stress

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Authors: Ahmed Elkholy

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Most power transmission cases use gearing in general, and worm gearing, in particular for energy utilization. Therefore, designing gears for minimum weight and maximum power transmission is the main target of this study. In this regard, a new approach has been developed to estimate the load share and stress distribution of worm gear sets. The approach is based upon considering the instantaneous tooth meshing stiffness where the worm gear drive was modelled as a series of spur gear slices, and each slice was analyzed separately using a well-established criteria. By combining the results obtained for all slices, the entire worm gear set loading and stressing was determined. The geometric modelling method presented, allows tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of the method introduced in this study, the instantaneous meshing stiffness and load share were obtained. In comparison with existing methods, this approach has both good analytical accuracy and less computing time.

Keywords: gear, load/stress distribution, worm, wheel, tooth stiffness, contact line

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Authors: Deena Moustafa

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The purpose of this paper is to describe the sources of parenting stress in mothers of Dual Diagnosis children (n =60) and examine the relationship between parenting stress and maternal psychological status (depression and well-being), also examine if there is any difference between the previous variables in different disabilities associated with Autism. A descriptive correlational design was used. Data were collected via online questionnaires. The study finds that there was no significant relationship between Autism Parenting Stress Index (APSI) scores and types of disability which associated with Autism, although Mothers with deaf autistic reported more parenting stress, Similar findings were found regarding Depressive Symptoms, as there was no significant relationship between (CESD-R) scores and types of disability which associated with Autism, also study finds that there was a significant correlation of the (APSI) with the (CESD-R) Mothers with higher overall parenting stress reported more depressive symptoms. Likewise, there was also a significant correlation between the (APSI) and the (RPWB) Mothers reporting more parenting stress also reported lower levels of well-being.

Keywords: parenting stress, maternal psychological statues, mothers of dual diagnosis, autism

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Authors: Kashif Jaeel, Bingru Huang

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Stress-induced accumulation of ethylene exacerbates drought damages in plants, and suppressing stress induction of ethylene may promote plant tolerance to heat stress. The objective of this study was to investigate the effects of endophytic bacteria (Paraburkholderia aspalathi) with 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase enzymes in suppressing ethylene production on plant tolerance to heat stress and underlying physiological mechanisms of P. aspalathi-regulation in creeping bentgrass (Agrostis stolonifera). A novel strain of P. aspalathi, ‘WSF23’, with ACC deaminase activity was used to inoculate the roots of plants (cv. ‘Penncross’) subjected to heat stress in controlled-environment chambers. Inoculation with WSF23 bacteria resulted in improved shoot and root growth during heat stress. The differential changes in metabolite regulation due to the bacterial inoculation could contribute to ACC deamination bacteria-improved heat tolerance in cool-season grass species.

Keywords: rhizobacteria, grass, heat, plant metabolism, soil bacteria

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Authors: Gurbir Kaur, Surinder Pal Singh

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The present study is a part of the research work on the effect of limestone powder (LP), silica fume (SF) and metakaolin (MK), on the flexural fatigue performance of steel fibre reinforced concrete (SFRC). Corrugated rectangular steel fibres of size 0.6x2.0x35 mm at a constant volume fraction of 1.0% have been incorporated in all mix combinations as the reinforcing material. Three mix combinations were prepared by replacing 30% of ordinary Portland cement (OPC) by weight with these cement additives in binary and ternary fashion to demonstrate their contribution. An experimental programme was conducted to obtain the fatigue lives of all mix combinations at various stress levels. The fatigue life data have been analysed as an attempt to determine the relationship between stress level ‘S’, number of cycles to failure ‘N’ and probability of failure ‘Pf’ for all mix combinations. The experimental coefficients of the fatigue equation have also been obtained from the fatigue data to represent the S-N-Pf curves analytically.

Keywords: cement additives, fatigue life, probability of failure, steel fibre reinforced concrete

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Authors: Mohd Sarfaraz

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The objective of this study is to investigate the work-life balance and job satisfaction among women employees in a hospital in India. It is believed that balancing a successful career with a family life or personal life can be challenging. WLB impacts on persons' satisfaction in their work and personal life roles. For this purpose, a questionnaire is developed with 22 items. The data collected from women employees who are working in a hospital in Aligarh, India. The constructs considered in this study include WLB and job satisfaction. The demographic and organisational variables considered in the study are genders, age and tenure of the job. Factors of WLB are flexible working conditions, work-life balance programs, and employee intention to change/leave a job, work pressure/stress and long working hours. This paper examines the relationship between work-family conflict, policies, and job and life satisfaction. Appropriate statistical tool using SPSS will be applied to achieve the objective. The anxiety over work-life balance is progressively becoming a common talk, especially for female employees.Increasing demands from the work and family domains represent a high strain for employees which even lead to the health problems among employees. Although it is believed that work-family role strain is more common among women employees. Therefore, the study will focus on these issues of WLB and job satisfaction among female professionals.

Keywords: work-life balance, job satisfaction, work- family conflict, health

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Authors: Rhea Mathews

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The purpose of the study is to investigate the effects of perceived social support and cultural self-efficacy on the acculturative stress of international postgraduate students in the United Kingdom. The study adopted Berry, Kim, Minde & Mok’s (1987) acculturative framework on acculturative stress and examined the relationship between the variables. The study hypothesized that perceived social support and cultural self-efficacy would predict lower levels of acculturative stress among students. Postgraduate students in the United Kingdom (N = 76) completed three surveys measuring the variables; Acculturative Stress Scale for International Students, Multidimensional Scale of Perceived Social Support, and Cultural Self-efficacy for Adolescents. To evaluate the role of the perceived social support and cultural self-efficacy in determining the acculturative stress level of international students, multiple linear regression was employed. Both independent variables exhibited a significant, negative relationship with acculturative stress (p < 0.001; p < 0.01). Results described that cultural self-efficacy and perceived social support significantly predicted acculturative stress (p < 0.01). Together, the variables accounted for 22% of the variance in acculturative stress scores (adjusted R² = 0.22), with cultural self-efficacy playing a larger role in predicting the dependent variable. Limitations and implications of the study are noted. The findings of the study are discussed in relation to enhancing international students’ acculturative experience when relocating to a new environment.

Keywords: acculturative stress, coping, cultural adjustment, cultural self-efficacy, international education, international students, migration, perceived social support

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Authors: Martin Mensinger, Marjolaine Pfaffinger, Matthias Haslbeck

Abstract:

The maintenance and expansion of the railway network represents a central task for transport planning in the future. In addition to the ultimate limit states, the aspects of resource conservation and sustainability are increasingly more necessary to include in the basic engineering. Therefore, as part of the AiF research project, ‘Integrated assessment of steel and composite railway bridges in accordance with sustainability criteria’, the entire lifecycle of engineering structures is involved in planning and evaluation, offering a way to optimize the design of steel bridges. In order to reduce the life cycle costs and increase the profitability of steel structures, it is particularly necessary to consider the demands on hanger connections resulting from fatigue. In order for accurate analysis, a number simulations were conducted as part of the research project on a finite element model of a reference bridge, which gives an indication of the internal forces of the individual structural components of a tied arch bridge, depending on the stress incurred by various types of trains. The calculations were carried out on a detailed FE-model, which allows an extraordinarily accurate modeling of the stiffness of all parts of the constructions as it is made up surface elements. The results point to a large impact of the formation of details on fatigue-related changes in stress, on the one hand, and on the other, they could depict construction-specific specifics over the course of adding stress. Comparative calculations with varied axle-stress distribution also provide information about the sensitivity of the results compared to the imposition of stress and axel distribution on the stress-resultant development. The calculated diagrams help to achieve an optimized hanger connection design through improved durability, which helps to reduce the maintenance costs of rail networks and to give practical application notes for the formation of details.

Keywords: fatigue, influence line, life cycle, tied arch bridge

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Authors: Vijay Reena Durai, Krithica Srinivasan

Abstract:

Introduction: The two fundamental skills involved in the growth and wellbeing of any child can be categorized into visual motor and perceptual skills. Visual stress is a disorder which is characterized by visual discomfort, blurred vision, misspelling words, skipping lines, letters bunching together. There is a need to understand the deficits in perceptual skills among children with visual stress. Aim: To estimate the association between visual stress and visual perceptual skills Objective: To compare visual perceptual skills of children with and without visual stress Methodology: Children between 8 to 15 years of age participated in this cross-sectional study. All children with monocular visual acuity better than or equal to 6/6 were included. Visual perceptual skills were measured using test for visual perceptual skills (TVPS) tool. Reading speed was measured with the chosen colored overlay using Wilkins reading chart and pattern glare score was estimated using a 3cpd gratings. Visual stress was defined as change in reading speed of greater than or equal to 10% and a pattern glare score of greater than or equal to 4. Results: 252 children participated in this study and the male: female ratio of 3:2. Majority of the children preferred Magenta (28%) and Yellow (25%) colored overlay for reading. There was a significant difference between the two groups (MD=1.24±0.6) (p<0.04, 95% CI 0.01-2.43) only in the sequential memory skills. The prevalence of visual stress in this group was found to be 31% (n=78). Binary logistic regression showed that odds ratio of having poor visual perceptual skills was OR: 2.85 (95% CI 1.08-7.49) among children with visual stress. Conclusion: Children with visual stress are found to have three times poorer visual perceptual skills than children without visual stress.

Keywords: visual stress, visual perceptual skills, colored overlay, pattern glare

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Authors: Hossein Kheirollahi, Yunhua Luo

Abstract:

Studying stress and strain trends in the femur and recognizing femur failure mechanism is very important for preventing hip fracture in the elderly. The aim of this study was to identify high stress and strain regions in the femur during normal walking and falling to find the mechanical behavior and failure mechanism of the femur. We developed a finite element model of the femur from the subject’s quantitative computed tomography (QCT) image and used it to identify potentially high stress and strain regions during the single-leg stance and the sideways fall. It was found that fracture may initiate from the superior region of femoral neck and propagate to the inferior region during a high impact force such as sideways fall. The results of this study showed that the femur bone is more sensitive to strain than stress which indicates the effect of strain, in addition to effect of stress, should be considered for failure analysis.

Keywords: finite element analysis, hip fracture, strain, stress

Procedia PDF Downloads 479