Effect of heating method on stress-rupture life

Science.gov (United States)

Bizon, P. T.; Calfo, F. D.

1977-01-01

The effect of radiant(furnace), resistance(electric current), burner(hot gas stream), and a combination of resistance and burner heating on intermediate time (100 to 300 hr) stress-rupture life and reduction of area was evaluated. All heating methods were studied using the nickel-based alloy Udimet 700 while all but burner heating were evaluated with the cobalt-based alloy Mar-M 509. Limited test results of eight other superalloys were also included in this study. Resistance heated specimens had about 20 to 30 percent of the stress-rupture life of radiant heated specimens. The limited burner heating data showed about a 50 percent life reduction as compared to the radiant heated tests. A metallurgical examination gave no explanation for these reductions.

Reduction of tensile residual stresses during the drawing process of tungsten wires

International Nuclear Information System (INIS)

Rodriguez Ripoll, Manel; Weygand, Sabine M.; Riedel, Hermann

2010-01-01

Tungsten wires are commonly used in the lighting industry as filaments for lamps. During the drawing process, the inhomogeneous deformation imparted by the drawing die causes tensile residual stresses at the wire surface in circumferential direction. These stresses have a detrimental effect for the wire because they are responsible for driving longitudinal cracks, known as splits. This work proposes two methods for reducing the residual stresses during wire drawing, namely applying an advanced die geometry and performing an inexpensive post-drawing treatment based on targeted bending operations. These two methods are analyzed with finite element simulations using material parameters obtained by mechanical tests on tungsten wires at different temperatures as input data. The computed results predict a substantial reduction of the circumferential residual stresses, thus reducing the risk of splitting.

Evolution of thermal stress and failure probability during reduction and re-oxidation of solid oxide fuel cell

Science.gov (United States)

Wang, Yu; Jiang, Wenchun; Luo, Yun; Zhang, Yucai; Tu, Shan-Tung

2017-12-01

The reduction and re-oxidation of anode have significant effects on the integrity of the solid oxide fuel cell (SOFC) sealed by the glass-ceramic (GC). The mechanical failure is mainly controlled by the stress distribution. Therefore, a three dimensional model of SOFC is established to investigate the stress evolution during the reduction and re-oxidation by finite element method (FEM) in this paper, and the failure probability is calculated using the Weibull method. The results demonstrate that the reduction of anode can decrease the thermal stresses and reduce the failure probability due to the volumetric contraction and porosity increasing. The re-oxidation can result in a remarkable increase of the thermal stresses, and the failure probabilities of anode, cathode, electrolyte and GC all increase to 1, which is mainly due to the large linear strain rather than the porosity decreasing. The cathode and electrolyte fail as soon as the linear strains are about 0.03% and 0.07%. Therefore, the re-oxidation should be controlled to ensure the integrity, and a lower re-oxidation temperature can decrease the stress and failure probability.

Residual stress reduction in the penetration nozzle weld joint by overlay welding

International Nuclear Information System (INIS)

Jiang, Wenchun; Luo, Yun; Wang, B.Y.; Tu, S.T.; Gong, J.M.

2014-01-01

Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

Using normalisation process theory to understand barriers and facilitators to implementing mindfulness-based stress reduction for people with multiple sclerosis.

Science.gov (United States)

Simpson, Robert; Simpson, Sharon; Wood, Karen; Mercer, Stewart W; Mair, Frances S

2018-01-01

Objectives To study barriers and facilitators to implementation of mindfulness-based stress reduction for people with multiple sclerosis. Methods Qualitative interviews were used to explore barriers and facilitators to implementation of mindfulness-based stress reduction, including 33 people with multiple sclerosis, 6 multiple sclerosis clinicians and 2 course instructors. Normalisation process theory provided the underpinning conceptual framework. Data were analysed deductively using normalisation process theory constructs (coherence, cognitive participation, collective action and reflexive monitoring). Results Key barriers included mismatched stakeholder expectations, lack of knowledge about mindfulness-based stress reduction, high levels of comorbidity and disability and skepticism about embedding mindfulness-based stress reduction in routine multiple sclerosis care. Facilitators to implementation included introducing a pre-course orientation session; adaptations to mindfulness-based stress reduction to accommodate comorbidity and disability and participants suggested smaller, shorter classes, shortened practices, exclusion of mindful-walking and more time with peers. Post-mindfulness-based stress reduction booster sessions may be required, and objective and subjective reports of benefit would increase clinician confidence in mindfulness-based stress reduction. Discussion Multiple sclerosis patients and clinicians know little about mindfulness-based stress reduction. Mismatched expectations are a barrier to participation, as is rigid application of mindfulness-based stress reduction in the context of disability. Course adaptations in response to patient needs would facilitate uptake and utilisation. Rendering access to mindfulness-based stress reduction rapid and flexible could facilitate implementation. Embedded outcome assessment is desirable.

he effect of mindfulness-based stress reduction in depression and blood sugar reduction diabetic patients with BIS type of personality

Directory of Open Access Journals (Sweden)

Fatemeh Mohammadi Shirmahaleh

2017-11-01

Full Text Available The present study was carried out to investigate the effectiveness of mindfulness-based stress reduction in depression reduction and blood sugar control in diabetic patients with Behavioral Inhibition type of personality. It was a quasi-experimental study with pretest/posttest design employing one experimental and one control group. The participants were 225 patients in Tehran. First, 30 patients with diabetes Type 2 were selected on the basis of interview and then randomly assigned to two experimental and control groups (n=15 in each group. Then, Wilson’s personality questionnaire and beck’s depression inventory were used to collect data. After conducting the pretest and measuring blood sugar level, the experimental group received an intervention in eight sessions of 120 minutes while the control group received no intervention. Finally, the posttest was administered to both groups. The results indicated that there was a significant difference between the results of the pretest and posttest, indicating that mindfulness-based training had a positive effect on the reduction of stress as well as reduction of blood sugar among patients with type 2 diabetes. Therefore, the mindfulness-based educational method can be used in clinics and healthcare centers to reduce stress and blood sugar levels among patients suffering from diabetes Type 2.

Complete relaxation of residual stresses during reduction of solid oxide fuel cells

DEFF Research Database (Denmark)

Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2015-01-01

reduce significantly over minutes. In this work the stresses are measured in-situ before and after the reduction by use of XRD. The phenomenon of accelerated creep has to be considered both in the production of stacks and in the analysis of the stress field in a stack based on anode supported SOFCs.......To asses the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of the anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. The phenomenon has previously been studied by simultaneous loading and reduction. With the recorded high creep rates, the stresses at the time of reduction should...

Residual stress reduction in beam welded joints by means of stress redistribution using defocused electron or laser beams; Eigenspannungsreduktion in strahlgeschweissten Naehten mittels Spannungsumlagerung durch den Einsatz defokussierter Elektronen- bzw. Laserstrahlen

Energy Technology Data Exchange (ETDEWEB)

Toelle, Florian

2013-08-01

Among the multiple advantages of beam welding processes the high longitudinal residual stresses in beam welds ranging till the local yield stress are one disadvantage. These high stresses can influence the service life of the welded components. The residual stresses in other welding processes exist in an equal high level but primarily in the transverse direction to the weld. To mitigate the high residual stresses a couple of methods were developed for these welding processes in the last decades. However these methods need large contact surfaces next to the welds for the installation of matched heating and cooling elements and other additional equipment. Furthermore, the previous developed stress mitigating processes offer a low efficiency for the small beam welds. The stress reduction by using the welding source after the welding process for a remote heat treatment of the welded components afford a flexible tool for the stress mitigation in beam welds. This method does not need any additional equipment and it is applicable for complex welding and component geometries. During this post welding heat treatment the material next to the weld is heated by the defocused electron or by the defocused laser beam, respectively, to temperatures of some hundreds degree Celsius. Hereby low plastic deformations in these regions are generated. While cooling down due to the thermal shrinkage the material between the weld and the heat treated region is compressed in longitudinal direction to the weld. This intermediate material zone constrained the shrinkage of the weld while cooling down from the melting temperature and leads to the high longitudinal residual stresses in the weld. In consequence of the compression of this intermediate zones by the heat treated zones the resistance to the shrinkage of the weld is lowered and the longitudinal stresses in the weld are reduced. In the process the quantity of the stress reduction is controlled by the selection of the process parameters

Evaluation of a Web-Based Holistic Stress Reduction Pilot Program Among Nurse-Midwives.

Science.gov (United States)

Wright, Erin M

2018-06-01

Work-related stress among midwives results in secondary traumatic stress, posttraumatic stress disorder, and job attrition. The purpose of this pilot project was to evaluate the effectiveness of a holistic, web-based program using holistic modalities for stress reduction and improved coping among certified nurse-midwives. A convenience sample of 10 midwives participated in a web-based holistic stress reduction intervention using yoga, mindfulness-based stress reduction, and meditation for four days each week over 4 weeks. Participants completed pre- and postintervention questionnaires (Perceived Stress Scale [PSS] and the Coping Self-Efficacy Scale [CSES]) for evaluation of effectiveness. The PSS means showed improvement in midwives' stress (16.4-12.3). The CSES means showed improvement in coping (174.8-214.5). Improvement was shown in each subscale of the CSES ("uses problem-focused coping": 19.2%; "stops unpleasant thoughts and emotions": 20.3%; and "gets support from family and friends": 16.6%). Findings suggest the potential for stress reduction and improved coping skills after using holistic techniques in a web-based format within a cohort of nurse-midwives. Further research of web-based, holistic intervention for stress reduction among midwives is warranted.

Chapter 13. Phonology: Stress and Vowel Reduction

OpenAIRE

Nesset, Tore

2015-01-01

Where do the complex stress patterns in Modern Russian come from? And why is Москва ‘Moscow’ pronounced with an unstressed [a] in the first syllable? In this chapter, you learn about the history of two related phenomena that cause problems for learners of Russian: stress patterns and vowel reduction in unstressed syllables. Click on the links below to learn more!13.2 Akanje

The use of self-Reiki for stress reduction and relaxation.

Science.gov (United States)

Bukowski, Elaine L

2015-09-01

More than one-third of college students reported the desire for stress reduction techniques and education. The purpose of this study was to determine the effects of a 20-week structured self-Reiki program on stress reduction and relaxation in college students. Students were recruited from Stockton University and sessions were conducted in the privacy of their residence. Twenty students completed the entire study consisting of 20 weeks of self-Reiki done twice weekly. Each participant completed a Reiki Baseline Credibility Scale, a Reiki Expectancy Scale, and a Perceived Stress Scale (PSS) after acceptance into the study. The PSS was completed every four weeks once the interventions were initiated. A global assessment questionnaire was completed at the end of the study. Logs summarizing the outcome of each session were submitted at the end of the study. With the exception of three participants, participants believed that Reiki is a credible technique for reducing stress levels. Except for two participants, participants agreed that Reiki would be effective in reducing stress levels. All participants experienced stress within the month prior to completing the initial PSS. There was a significant reduction in stress levels from pre-study to post-study. There was a correlation between self-rating of improvement and final PSS scores. With one exception, stress levels at 20 weeks did not return to pre-study stress levels. This study supports the hypothesis that the calming effect of Reiki may be achieved through the use of self-Reiki.

Responses to reductive stress in the cardiovascular system.

Science.gov (United States)

Handy, Diane E; Loscalzo, Joseph

2017-08-01

There is a growing appreciation that reductive stress represents a disturbance in the redox state that is harmful to biological systems. On a cellular level, the presence of increased reducing equivalents and the lack of beneficial fluxes of reactive oxygen species can prevent growth factor-mediated signaling, promote mitochondrial dysfunction, increase apoptosis, and decrease cell survival. In this review, we highlight the importance of redox balance in maintaining cardiovascular homeostasis and consider the tenuous balance between oxidative and reductive stress. We explain the role of reductive stress in models of protein aggregation-induced cardiomyopathies, such as those caused by mutations in αB-crystallin. In addition, we discuss the role of NADPH oxidases in models of heart failure and ischemia-reperfusion to illustrate how oxidants may mediate the adaptive responses to injury. NADPH oxidase 4, a hydrogen peroxide generator, also has a major role in promoting vascular homeostasis through its regulation of vascular tone, angiogenic responses, and effects on atherogenesis. In contrast, the lack of antioxidant enzymes that reduce hydrogen peroxide, such as glutathione peroxidase 1, promotes vascular remodeling and is deleterious to endothelial function. Thus, we consider the role of oxidants as necessary signals to promote adaptive responses, such as the activation of Nrf2 and eNOS, and the stabilization of Hif1. In addition, we discuss the adaptive metabolic reprogramming in hypoxia that lead to a reductive state, and the subsequent cellular redistribution of reducing equivalents from NADH to other metabolites. Finally, we discuss the paradoxical ability of excess reducing equivalents to stimulate oxidative stress and promote injury. Copyright © 2017 Elsevier Inc. All rights reserved.

Effectiveness of a smartphone-based worry-reduction training for stress reduction: A randomized-controlled trial.

Science.gov (United States)

Versluis, Anke; Verkuil, Bart; Spinhoven, Philip; F Brosschot, Jos

2018-04-03

Perseverative cognition (e.g. worry) and unconscious stress are suggested to be important mediators in the relation between stressors and physiological health. We examined whether a smartphone-based worry-reduction training improved a physiological marker of stress (i.e. increased heart rate variability [HRV]) and unconscious stress. Randomised-controlled trial was conducted with individuals reporting work stress (n = 136). Participants were randomised to the experimental, control or waitlist condition (resp. EC, CC, WL). The EC and CC registered emotions five times daily for four weeks. The EC additionally received a worry-reduction training with mindfulness exercises. Primary outcome was 24-h assessments of HRV measured at pre-, mid- and post-intervention. Secondary outcomes were implicit affect and stress. Effects on heart rate and other psychological outcomes were explored. A total of 118 participants completed the study. No change from pre- to post-intervention was observed for the primary or secondary outcomes. The change over time was not different between conditions. Findings suggest that the training was ineffective for improving HRV or psychological stress. Future studies may focus on alternative smartphone-based stress interventions, as stress levels are high in society. There is need for easy interventions and smartphones offer possibilities for this.

Simplified elastic-plastic analysis of reinforced concrete structures - design method for self-restraining stress

International Nuclear Information System (INIS)

Aihara, S.; Atsumi, K.; Ujiie, K.; Satoh, S.

1981-01-01

Self-restraining stresses generate not only moments but also axial forces. Therefore the moment and force equilibriums of cross section are considered simultaneously, in combination with other external forces. Thus, under this theory, two computer programs are prepared for. Using these programs, the design procedures which considered the reduction of self-restraining stress, become easy if the elastic design stresses, which are separated normal stresses and self-restraining stresses, are given. Numerical examples are given to illustrate the application of the simplified elastic-plastic analysis and to study its effectiveness. First this method is applied to analyze an upper shielding wall in MARK-2 type's Reactor building. The results are compared with those obtained by the elastic-plastic analysis of Finite Element Method. From this comparison it was confirmed that the method described, had adequate accuracy for re-bar design. As a second example, Mat slab of Reactor building is analyzed. The quantity of re-bars calculated by this method, comes to about two third of re-bars less than those required when self-restraining stress is considered as normal stress. Also, the self-restraining stress reduction factor is about 0.5. (orig./HP)

A Theory for the Incubation Period Following a Stress Reduction During Creep

DEFF Research Database (Denmark)

Bilde-Sørensen, Jørgen

1978-01-01

incubation period is much shorter than the time needed to establish an equilibrium structure at the new lower stress. The dependence of dislocation line tension upon line length is taken into account; as a result of this, recovery rates are predicted to depend on stress to a power larger than three......A dislocation model is presented for the phenomena following a stress reduction during creep. It is suggested that an incubation period for the production of new mobile dislocations arises because attractive junctions on the verge of breaking just before the stress reduction are no longer so after...... the stress reduction. The breaking stress of the junctions must be lowered by climb movements in the surrounding network before the junctions can break and release new mobile dislocations. On the basis of these concepts, an expression is derived for the length of the incubation period. This theoretical...

External caps: An approach to stress reduction in balloons

Science.gov (United States)

Hazlewood, K. H.

Recent findings of the catastrophic balloon failures investigation in the U.S.A. indicate that very large gross inflations, in balloons using present design philosophy, over-stress currently available materials. External caps are proposed as an economic approach to reducting those stresses to an acceptable level.

VR Mobile Solutions For Chronic Stress Reduction in Young Adults.

Science.gov (United States)

Gao, Kenneth; Boyd, Chelsie; Wiederhold, Mark D; Wiederhold, Brenda K

2014-01-01

Chronic stress in young adults has become a growing problem within recent decades and many are unable to find cost-effective and accessible treatment for psychological stress in their daily lives. We analyze the market of using a mobile application, Positive Technology, as a solution. Eleven participants, aged between 18 and 24, participated in the exercise. Self-reported stress reduction was measured via an online marketing survey, while physiological measurements were monitored via peripheral devices. Secondary goals assessed the app's ease-of-use, accessibility, and cost. Results indicate that participants enjoyed the availability of the mobile solution and found the app to be fun and easy to learn. Stress levels were reduced in 73% of the participants, with higher effects in females and in participants aged 18-24. We conclude that the mobile platform is an effective means of delivering psychological stress reduction, and could provide an accessible, cost-effective solution.

Effect of mindfulness-based stress reduction on sleep quality

DEFF Research Database (Denmark)

Andersen, Signe; Würtzen, Hanne; Steding-Jessen, Marianne

2013-01-01

The prevalence of sleep disturbance is high among cancer patients, and the sleep problems tend to last for years after the end of treatment. As part of a large randomized controlled clinical trial (the MICA trial, NCT00990977) of the effect of mindfulness-based stress reduction (MBSR) on psycholo......The prevalence of sleep disturbance is high among cancer patients, and the sleep problems tend to last for years after the end of treatment. As part of a large randomized controlled clinical trial (the MICA trial, NCT00990977) of the effect of mindfulness-based stress reduction (MBSR...

Mindfulness-based stress reduction for GPs: results of a controlled mixed methods pilot study in Dutch primary care

NARCIS (Netherlands)

Verweij, H.; Waumans, R.C.; Smeijers, D.; Lucassen, P.L.; Donders, A.R.T.; Horst, H.E. van der; Speckens, A.E.M.

2016-01-01

BACKGROUND: Burnout is highly prevalent in GPs and can have a negative influence on their wellbeing, performance, and patient care. Mindfulness-based stress reduction (MBSR) may be an effective intervention to decrease burnout symptoms and increase wellbeing. AIM: To gain insight into the

Modern Reduction Methods

CERN Document Server

Andersson, Pher G

2008-01-01

With its comprehensive overview of modern reduction methods, this book features high quality contributions allowing readers to find reliable solutions quickly and easily. The monograph treats the reduction of carbonyles, alkenes, imines and alkynes, as well as reductive aminations and cross and heck couplings, before finishing off with sections on kinetic resolutions and hydrogenolysis. An indispensable lab companion for every chemist.

A pilot study on mindfulness based stress reduction for smokers

Directory of Open Access Journals (Sweden)

Baker Timothy B

2007-01-01

Full Text Available Abstract Background Mindfulness means paying attention in the present moment, non-judgmentally, without commentary or decision-making. We report results of a pilot study designed to test the feasibility of using Mindfulness Based Stress Reduction (MBSR (with minor modifications as a smoking intervention. Methods MBSR instructors provided instructions in mindfulness in eight weekly group sessions. Subjects attempted smoking cessation during week seven without pharmacotherapy. Smoking abstinence was tested six weeks after the smoking quit day with carbon monoxide breath test and 7-day smoking calendars. Questionnaires were administered to evaluate changes in stress and affective distress. Results 18 subjects enrolled in the intervention with an average smoking history of 19.9 cigarettes per day for 26.4 years. At the 6-week post-quit visit, 10 of 18 subjects (56% achieved biologically confirmed 7-day point-prevalent smoking abstinence. Compliance with meditation was positively associated with smoking abstinence and decreases in stress and affective distress. Discussions and conclusion The results of this study suggest that mindfulness training may show promise for smoking cessation and warrants additional study in a larger comparative trial.

Reductions in labour capacity from heat stress under climate warming

Science.gov (United States)

Dunne, John P.; Stouffer, Ronald J.; John, Jasmin G.

2013-06-01

A fundamental aspect of greenhouse-gas-induced warming is a global-scale increase in absolute humidity. Under continued warming, this response has been shown to pose increasingly severe limitations on human activity in tropical and mid-latitudes during peak months of heat stress. One heat-stress metric with broad occupational health applications is wet-bulb globe temperature. We combine wet-bulb globe temperatures from global climate historical reanalysis and Earth System Model (ESM2M) projections with industrial and military guidelines for an acclimated individual's occupational capacity to safely perform sustained labour under environmental heat stress (labour capacity)--here defined as a global population-weighted metric temporally fixed at the 2010 distribution. We estimate that environmental heat stress has reduced labour capacity to 90% in peak months over the past few decades. ESM2M projects labour capacity reduction to 80% in peak months by 2050. Under the highest scenario considered (Representative Concentration Pathway 8.5), ESM2M projects labour capacity reduction to less than 40% by 2200 in peak months, with most tropical and mid-latitudes experiencing extreme climatological heat stress. Uncertainties and caveats associated with these projections include climate sensitivity, climate warming patterns, CO2 emissions, future population distributions, and technological and societal change.

Aquatic-Aerobic Exercise as a Means of Stress Reduction during Pregnancy

OpenAIRE

Parker, Kara Mallory; Smith, Sheila A.

2003-01-01

The goals of this research were to explore the current literature regarding associations between psychological stress and adverse fetal outcome, associations between aerobic exercise and psychological stress reduction, and associations between aerobic exercise and fetal outcome. The published studies that were located provide evidence of the following: 1) Stress reactivity increases physiologically during pregnancy, 2) pregnant women may experience additional stressors that are usually not ex...

Stress reduction in tungsten films using nanostructured compliant layers

International Nuclear Information System (INIS)

Karabacak, Tansel; Picu, Catalin R.; Senkevich, Jay J.; Wang, G.-C.; Lu, T.-M.

2004-01-01

The residual stress in thin films is a major limiting factor for obtaining high quality films. We present a strategy for stress reduction in sputter deposited films by using a nanostructured compliant layer obtained by the oblique angle deposition technique, sandwiched between the film and the substrate. The technique is all in situ, does not require any lithography steps, and the nanostructured layer is made from the same material as the deposited thin film. By using this approach we were able to reduce stress values by approximately one order of magnitude in sputter deposited tungsten films. These lower stress thin films also exhibit stronger adhesion to the substrate, which retards delamination buckling. This technique allows the growth of much thicker films and has enhanced structural stability. A model is developed to explain the stress relief mechanism and the stronger adhesion associated with the presence of the nanostructured compliant layer

Assessment of residual stress of 7050-T7452 aluminum alloy forging using the contour method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zheng [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Yang, Yinfei, E-mail: yyfgoat@nuaa.edu.cn [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Li, Liang [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Chen, Bo; Tian, Hui [Xi’an Aircraft Industrial (Group) Co. Ltd., Xi’an 710000 (China)

2015-09-17

The cold-compression stress relief process has been used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings. However, this method does not completely relieve the stress. Longitudinal residual stresses in 7050-T7452 aluminum alloy forging were measured with contour method. The measuring procedure of the contour method including specimen cutting under clamps with a wire electrical discharge machine, contour measurement of the cut surface with a laser scanner, careful data processing and elastic finite element analysis was introduced in detail. In addition, multiple cuts were used to map cross sectional stress at different cut surfaces. Finally, the longitudinal residual stress throughout the cut plane was mapped, and through thickness longitudinal stress profiles were also analyzed. Investigated results suggest that spatial variation of stress distribution can be attributed to the non-uniform plastic deformation of the cold-compression stress relief process. The overall reduction of peak stress magnitudes is approximately 43–79%.

Assessment of residual stress of 7050-T7452 aluminum alloy forging using the contour method

International Nuclear Information System (INIS)

Zhang, Zheng; Yang, Yinfei; Li, Liang; Chen, Bo; Tian, Hui

2015-01-01

The cold-compression stress relief process has been used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings. However, this method does not completely relieve the stress. Longitudinal residual stresses in 7050-T7452 aluminum alloy forging were measured with contour method. The measuring procedure of the contour method including specimen cutting under clamps with a wire electrical discharge machine, contour measurement of the cut surface with a laser scanner, careful data processing and elastic finite element analysis was introduced in detail. In addition, multiple cuts were used to map cross sectional stress at different cut surfaces. Finally, the longitudinal residual stress throughout the cut plane was mapped, and through thickness longitudinal stress profiles were also analyzed. Investigated results suggest that spatial variation of stress distribution can be attributed to the non-uniform plastic deformation of the cold-compression stress relief process. The overall reduction of peak stress magnitudes is approximately 43–79%

Inverse method for stress monitoring in pressure components of steam generators

International Nuclear Information System (INIS)

Duda, P.

2003-01-01

The purpose of this work is to formulate a space marching method, which can be used to solve inverse multidimensional heat conduction problems. The method is designed to reconstruct the transient temperature distribution in a whole construction element based on measured temperatures taken at selected points inside or on the outer surface of the construction element. Next, the Finite Element Method is used to calculate thermal stresses and stresses caused by other loads such as, for instance, internal pressure. The developed method for solving temperature and total stress distribution will be tested using the measured temperatures generated from a direct solution. Transient temperature and total stress distribution obtained from method presented below will be compared with the values obtained from the direct solution. Finally, the presented method will be applied in order to monitor temperature and stress distribution in an outlet header using the real measured temperature values at seven points on the header's outer surface during the power boiler's shut down operation. The presented method allows to optimize the power block's start-up and shut-down operations, contributes to the reduction of heat loss during these operations and to the extension of power block's life. The fatigue and creep usage factor can be computed in an on-line mode. The presented method herein can be applied to monitoring systems that work in conventional as well as in nuclear power plants. (author)

Robust methods for data reduction

CERN Document Server

Farcomeni, Alessio

2015-01-01

Robust Methods for Data Reduction gives a non-technical overview of robust data reduction techniques, encouraging the use of these important and useful methods in practical applications. The main areas covered include principal components analysis, sparse principal component analysis, canonical correlation analysis, factor analysis, clustering, double clustering, and discriminant analysis.The first part of the book illustrates how dimension reduction techniques synthesize available information by reducing the dimensionality of the data. The second part focuses on cluster and discriminant analy

A Program to Protect Integrity of Body-Mind-Spirit: Mindfulness Based Stress Reduction Program

Directory of Open Access Journals (Sweden)

Oznur Korukcu

2015-03-01

Full Text Available Mindfulness-based applications allow health care staffs to understand themselves as well as other individuals. Awareness based applications are not only stress reduction techniques but also a way of understanding the life and human existence, and it should not be only used to cope with the diseases. Emotions, thoughts and judgments of people might give direction to their life sometimes. Accessing a life without judgment and negative feelings brings a peaceful and happy life together. Mindfulness based stress reduction exercises may help to enjoy the present time, to cope with the challenges, stress and diseases and accept the negative life experiences rather than to question their reasons. About three decades ago, Kabat-Zin conducted the first investigation of Mindfulness-Based Stress Reduction program which is used commonly all around the world. The 8-weeks program, which contains mindful living exercises (such as eating, walking, cooking, etc., yoga, body scan and meditation practices, requires doing daily life activity and meditation with attention, openness and acceptance. The aim of this review article is to give information about Mindfulness Based Stress Reduction program and to emphasize its importance. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2015; 7(1: 68-80

Applicabilities of ship emission reduction methods

Energy Technology Data Exchange (ETDEWEB)

Guleryuz, Adem [ARGEMAN Research Group, Marine Division (Turkey)], email: ademg@argeman.org; Kilic, Alper [Istanbul Technical University, Maritime Faculty, Marine Engineering Department (Turkey)], email: enviromarineacademic@yahoo.com

2011-07-01

Ships, with their high consumption of fossil fuels to power their engines, are significant air polluters. Emission reduction methods therefore need to be implemented and the aim of this paper is to assess the advantages and disadvantages of each emissions reduction method. Benefits of the different methods are compared, with their disadvantages and requirements, to determine the applicability of such solutions. The methods studied herein are direct water injection, humid air motor, sea water scrubbing, diesel particulate filter, selected catalytic reduction, design of engine components, exhaust gas recirculation and engine replacement. Results of the study showed that the usefulness of each emissions reduction method depends on the particular case and that an evaluation should be carried out for each ship. This study pointed out that methods to reduce ship emissions are available but that their applicability depends on each case.

A pilot randomized trial teaching mindfulness-based stress reduction to traumatized youth in foster care.

Science.gov (United States)

Jee, Sandra H; Couderc, Jean-Philippe; Swanson, Dena; Gallegos, Autumn; Hilliard, Cammie; Blumkin, Aaron; Cunningham, Kendall; Heinert, Sara

2015-08-01

This article presents a pilot project implementing a mindfulness-based stress reduction program among traumatized youth in foster and kinship care over 10 weeks. Forty-two youth participated in this randomized controlled trial that used a mixed-methods (quantitative, qualitative, and physiologic) evaluation. Youth self-report measuring mental health problems, mindfulness, and stress were lower than anticipated, and the relatively short time-frame to teach these skills to traumatized youth may not have been sufficient to capture significant changes in stress as measured by electrocardiograms. Main themes from qualitative data included expressed competence in managing ongoing stress, enhanced self-awareness, and new strategies to manage stress. We share our experiences and recommendations for future research and practice, including focusing efforts on younger youth, and using community-based participatory research principles to promote engagement and co-learning. CLINICALTRIALS.GOV: Protocol Registration System ID NCT01708291. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mindfulness based stress reduction for medical students: optimising student satisfaction and engagement.

Science.gov (United States)

Aherne, Declan; Farrant, Katie; Hickey, Louise; Hickey, Emma; McGrath, Lisa; McGrath, Deirdre

2016-08-18

Medical practitioners and students are at increased risk of a number of personal and psychological problems. Stress and anxiety due to work-load and study requirements are common and self-care methods are important in maintaining well-being. The current study examines perceptions of and satisfaction ratings with a mindfulness based stress reduction (MBSR) programme for 1(st) year (compulsory) and 2(nd) year (optional) Graduate Entry Medical School students. A mixed method pre and post study of Year 1 (n = 140) and Year 2 (n = 88) medical students completing a 7 week MBSR course compared student satisfaction ratings. Thematic analysis of feedback from the students on their perception of the course was also carried out. Year 1 students (compulsory course) were less satisfied with content and learning outcomes than Year 2 students (optional course) (p levels of satisfaction and positive feedback when delivered on an optional basis. Catering for the individual needs of the participant and promoting a safe environment are core elements of a successful self-care programme.

Study of stress-reduction effects on creep behaviour of AISI-316 stainless steel

International Nuclear Information System (INIS)

Alegria, R.V.

1984-01-01

Creep tests were performed in 316 austenitic stainless steel at 1006 0 K in both solution treated and in 15% pre-deformed samples. The dislocation substructure in the steady state stage was analysed for the applied stresses 109,30 MPa and 208,23 MPa. The influence of the prestraining conditions was verified. The strutural modifications occurring after a stress reduction were analysed in stress reduction tests. The results are discussed in terms of current ideas and its shown that the increase in creep resistance, introduced by a 15% pre-strain, is due to the presence of a subgrain structure and carbides which act as obstacles to dislocation motion. (E.G.) [pt

Anelasticity of olivine single crystals investigated by stress-reduction tests and high-angular resolution electron backscatter diffraction

Science.gov (United States)

Wallis, D.; Hansen, L. N.; Kempton, I.; Wilkinson, A. J.

2017-12-01

Geodynamic phenomena, including glacial isostatic adjustment and postseismic deformation, can involve transient deformation in response to changes in differential stress acting on mantle rocks. As such, rheological models of transient deformation are incorporated in predictions of associated processes, including sea-level rise and stress redistribution after earthquakes. However, experimental constraints on rheological models for transient deformation of mantle materials are sparse. In particular, experiments involving stress reductions have been lacking. Moreover, a material's response to a reduction in stress can provide clues to the microphysical processes controlling deformation. To constrain models of transient deformation of mantle rocks we performed stress-reduction tests on single crystals of olivine at 1250-1300°C. Mechanical and piezoelectric actuators controlled constant initial stress during creep. At various strain intervals stress was reduced near-instantaneously using the piezoelectric actuator, inducing both elastic and anelastic (time-dependent) lengthening of the samples. A range of magnitudes of stress reduction were applied, typically unloading 10-90% of the initial stress. High-angular resolution electron backscatter diffraction (HR-EBSD), based on cross-correlation of diffraction patterns, was used to map dislocation density and elastic strain distributions in the recovered samples. Magnitudes of anelastic back-strain increase with increasing magnitudes of stress reduction and show a marked increase when stress reductions exceed 50% of the initial stress, consistent with previous observations in metals and alloys. This observation is inconsistent with the Burgers rheological model commonly used to describe transient behaviour and suggests that the style of rheological behaviour depends on the magnitude of stress change. HR-EBSD maps reveal that the crystal lattices are smoothly curved and generally lack subgrain boundaries and elastic strain

Generalized Time-Limited Balanced Reduction Method

DEFF Research Database (Denmark)

Shaker, Hamid Reza; Shaker, Fatemeh

2013-01-01

In this paper, a new method for model reduction of bilinear systems is presented. The proposed technique is from the family of gramian-based model reduction methods. The method uses time-interval generalized gramians in the reduction procedure rather than the ordinary generalized gramians...... and in such a way it improves the accuracy of the approximation within the time-interval which the method is applied. The time-interval generalized gramians are the solutions to the generalized time-interval Lyapunov equations. The conditions for these equations to be solvable are derived and an algorithm...

Inverse method for temperature and stress monitoring in complex-shaped bodies

International Nuclear Information System (INIS)

Duda, Piotr; Taler, Jan E- mail: aler@ss5.mech.pk.edu.pl; Roos, Eberhard

2004-01-01

The purpose of this work is to formulate a space marching method, which an be used to solve inverse multidimensional heat conduction problems. The method is designed to reconstruct the transient temperature distribution in a hole construction element based on measured temperatures taken at selected points on the outer surface of the construction element. Next, the Finite element Method is used to calculate thermal stresses and stresses caused by other loads such as, for instance, internal pressure. The developed method or solving temperature and total stress distribution is tested using the measured temperatures generated from a direct solution. Transient temperature nd total stress distributions obtained from the method presented below are compared with the values obtained from the direct solution. Finally, the resented method is experimentally verified during the cooling of a hick-walled cylindrical element. The model of a pressure vessel was reheated at 300 deg.C and then cooled by cold water injection. The comparison of results obtained from the inverse method with experimental data hows the high accuracy of the developed method. The presented method allows o optimize the power block's start-up and shut-down operations, contributes o the reduction of heat loss during these operations and to the extension of power block's life. The fatigue and creep usage factor can be computed in an n-line mode. The presented method herein can be applied to monitoring systems that work in conventional as well as in nuclear power plants

Recruiting and retaining family caregivers to a randomized controlled trial on mindfulness-based stress reduction.

Science.gov (United States)

Whitebird, Robin R; Kreitzer, Mary Jo; Lewis, Beth A; Hanson, Leah R; Crain, A Lauren; Enstad, Chris J; Mehta, Adele

2011-09-01

Caregivers for a family member with dementia experience chronic long-term stress that may benefit from new complementary therapies such as mindfulness-based stress reduction. Little is known however, about the challenges of recruiting and retaining family caregivers to research on mind-body based complementary therapies. Our pilot study is the first of its kind to successfully recruit caregivers for a family member with dementia to a randomized controlled pilot study of mindfulness-based stress reduction. The study used an array of recruitment strategies and techniques that were tailored to fit the unique features of our recruitment sources and employed retention strategies that placed high value on establishing early and ongoing communication with potential participants. Innovative recruitment methods including conducting outreach to health plan members and generating press coverage were combined with standard methods of community outreach and paid advertising. We were successful in exceeding our recruitment goal and retained 92% of the study participants at post-intervention (2 months) and 90% at 6 months. Recruitment and retention for family caregiver interventions employing mind-body based complementary therapies can be successful despite many challenges. Barriers include cultural perceptions about the use and benefit of complementary therapies, cultural differences with how the role of family caregiver is perceived, the use of group-based designs requiring significant time commitment by participants, and travel and respite care needs for busy family caregivers. Copyright © 2011 Elsevier Inc. All rights reserved.

Characteristics of Reduction Gear in Electric Agricultural Vehicle

Science.gov (United States)

Choi, W. S.; Pratama, P. S.; Supeno, D.; Jeong, S. W.; Byun, J. Y.; Woo, J. H.; Lee, E. S.; Park, C. S.

2018-03-01

In electric agricultural machine a reduction gear is needed to convert the high speed rotation motion generated by DC motor to lower speed rotation motion used by the vehicle. The reduction gear consists of several spur gears. Spur gears are the most easily visualized gears that transmit motion between two parallel shafts and easy to produce. The modelling and simulation of spur gears in DC motor reduction gear is important to predict the actual motion behaviour. A pair of spur gear tooth in action is generally subjected to two types of cyclic stress: contact stress and bending stress. The stress may not attain their maximum values at the same point of contact fatigue. These types of failure can be minimized by analysis of the problem during the design stage and creating proper tooth surface profile with proper manufacturing methods. To improve its life expectation in this study modal and stress analysis of reduction gear is simulated using ANSYS workbench based on finite element method (FEM). The modal analysis was done to understand reduction gear deformation behaviour when vibration occurs. FEM static stress analysis is also simulated on reduction gear to simulate the gear teeth bending stress and contact stress behaviour.

Stress reduction of Cu-doped diamond-like carbon films from ab initio calculations

Directory of Open Access Journals (Sweden)

Xiaowei Li

2015-01-01

Full Text Available Structure and properties of Cu-doped diamond-like carbon films (DLC were investigated using ab initio calculations. The effect of Cu concentrations (1.56∼7.81 at.% on atomic bond structure was mainly analyzed to clarify the residual stress reduction mechanism. Results showed that with introducing Cu into DLC films, the residual compressive stress decreased firstly and then increased for each case with the obvious deterioration of mechanical properties, which was in agreement with the experimental results. Structural analysis revealed that the weak Cu-C bond and the relaxation of both the distorted bond angles and bond lengths accounted for the significant reduction of residual compressive stress, while at the higher Cu concentration the increase of residual stress attributed to the existence of distorted Cu-C structures and the increased fraction of distorted C-C bond lengths.

Mindfulness-based stress reduction for residents: A randomized controlled trial

NARCIS (Netherlands)

Verweij, H.; Ravesteijn, H.J. van; Hooff, M.L.M. van; Lagro-Janssen, A.L.M.; Speckens, A.E.M.

2018-01-01

Background: Burnout is highly prevalent in residents. No randomized controlled trials have been conducted measuring the effects of Mindfulness-Based Stress Reduction (MBSR) on burnout in residents. Objective: To determine the effectiveness of MBSR in reducing burnout in residents. Design: A

Influence of Carrier Gas Composition on the Stress of Al₂O₃ Coatings Prepared by the Aerosol Deposition Method.

Science.gov (United States)

Schubert, Michael; Exner, Jörg; Moos, Ralf

2014-08-05

Al₂O₃ films were prepared by the aerosol deposition method at room temperature using different carrier gas compositions. The layers were deposited on alumina substrates and the film stress of the layer was calculated by measuring the deformation of the substrate. It was shown that the film stress can be halved by using oxygen instead of nitrogen or helium as the carrier gas. The substrates were annealed at different temperature steps to gain information about the temperature dependence of the reduction of the implemented stress. Total relaxation of the stress can already be achieved at 300 °C. The XRD pattern shows crystallite growth and reduction of microstrain while annealing.

Recovery of Work-Related Stress: Complaint Reduction and Work-Resumption are Relatively Independent Processes.

Science.gov (United States)

de Vente, Wieke; Kamphuis, Jan Henk; Blonk, Roland W B; Emmelkamp, Paul M G

2015-09-01

The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the association between predictors and work-resumption. Seventy-one patients on sickness-leave because of work-related stress complaints were followed over a period of 13 months. Predictors comprised personal (demographics, coping, cognitions), work-related (job-characteristics, social support), and illness-related (complaint duration, absence duration) variables. Dependent variables were distress complaints, burnout complaints, and work-resumption. Complaints reduced considerably over time to borderline clinical levels and work-resumption increased to 68% at 13 months. Predictors of stronger reduction of distress complaints were male gender, less working hours, less decision authority, more co-worker support, and shorter absence duration. Predictors of stronger reduction of burnout complaints were male gender, lower age, high education, less avoidant coping, less decision authority, more job security, and more co-worker support. Predictors of work-resumption were lower age and stronger reduction of burnout complaints. No indication for a mediating role of burnout complaints between the predictor age and work-resumption was found. Complaint reduction and work-resumption are relatively independent processes. Symptom reduction is influenced by individual and work-related characteristics, which holds promise for a multidisciplinary treatment approach for work-related stress.

Mindfulness-based stress reduction for breast cancer patients: a mixed method study on what patients experience as a suitable stage to participate

NARCIS (Netherlands)

Bisseling, Else M.; Schellekens, Melanie P. J.; Jansen, Ellen T. M.; van Laarhoven, Hanneke W. M.; Prins, Judith B.; Speckens, Anne E. M.

2017-01-01

Breast cancer is associated with high levels of psychological distress. Mindfulness-based stress reduction (MBSR) has proven to be effective in reducing distress in cancer patients. In several studies, patients who are currently undergoing somatic anticancer treatment are excluded from participating

Long-term occupational stress is associated with regional reductions in brain tissue volumes.

Directory of Open Access Journals (Sweden)

Eva Blix

Full Text Available There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM and white matter (WM volumes, and the volumes of hippocampus, caudate, and putamen - structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment.

Long-Term Occupational Stress Is Associated with Regional Reductions in Brain Tissue Volumes

Science.gov (United States)

Blix, Eva; Perski, Aleksander; Berglund, Hans; Savic, Ivanka

2013-01-01

There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM) and white matter (WM) volumes, and the volumes of hippocampus, caudate, and putamen – structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment. PMID:23776438

Effects of Mindfulness-Based Stress Reduction on the Mental Health of Clinical Clerkship Students: A Cluster-Randomized Controlled Trial

NARCIS (Netherlands)

Dijk, I. van; Lucassen, P.L.B.J.; Akkermans, R.P.; Engelen, B.G.M. van; Weel, C. van; Speckens, A.E.M.

2017-01-01

PURPOSE: To examine the effect of mindfulness-based stress reduction training (MBSR) on the mental health of medical students during clinical clerkships. METHOD: Between February 2011 and May 2014, the authors conducted a cluster-randomized controlled trial of clerkships as usual (CAU) and

Recovery of Work-Related Stress: Complaint Reduction and Work-Resumption are Relatively Independent Processes

NARCIS (Netherlands)

Vente, W. de; Kamphuis, J.H.; Blonk, R.W.; Emmelkamp, P.M.

2015-01-01

Purpose The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the

Recovery of work-related stress: Complaint reduction and work-resumption are relatively independent processes

NARCIS (Netherlands)

de Vente, W.; Kamphuis, J.H.; Blonk, R.W.B.; Emmelkamp, P.M.G.

2015-01-01

Purpose: The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the

Mindfulness-based stress reduction: an intervention to enhance the effectiveness of nurses' coping with work-related stress.

Science.gov (United States)

Smith, Sarah A

2014-06-01

This critical literature review explored the current state of the science regarding mindfulness-based stress reduction (MBSR) as a potential intervention to improve the ability of nurses to effectively cope with stress. Literature sources include searches from EBSCOhost, Gale PowerSearch, ProQuest, PubMed Medline, Google Scholar, Online Journal of Issues in Nursing, and reference lists from relevant articles. Empirical evidence regarding utilizing MBSR with nurses and other healthcare professionals suggests several positive benefits including decreased stress, burnout, and anxiety; and increased empathy, focus, and mood. Nurse use of MBSR may be a key intervention to help improve nurses' ability to cope with stress and ultimately improve the quality of patient care provided. © 2014 NANDA International, Inc.

Methods for Alleviating Stress and Increasing Resilience in the Midwifery Community: A Scoping Review of the Literature.

Science.gov (United States)

Wright, Erin M; Matthai, Maude Theo; Warren, Nicole

2017-11-01

Work-related stress and exposure to traumatic birth have deleterious impacts on midwifery practice, the midwife's physiologic well-being, and the midwifery workforce. This is a global phenomenon, and the specific sources of this stress vary dependent on practice setting. This scoping review aims to determine which, if any, modalities help to reduce stress and increase resilience among a population of midwives. A scoping review of the literature published between January 2011 and September 2016 using PubMed, CINAHL, Embase, PsycINFO, and Cochrane databases was performed. Of the initial 796 reviewed records, 6 met inclusion criteria. Three of the 6 included studies were quantitative in nature, 2 were qualitative, and one used mixed methods. Countries where studies were conducted include Uganda, Iran, the United Kingdom, Israel, and Australia. Three of the studies used interventions for stress reduction and increased coping. Two of these 3 used a mindfulness-based stress reduction program resulting in improved stress levels and coping skills. In each study, midwives express a desire for work-based programs and support from colleagues and employers for increasing coping abilities. These studies focused on stress reduction and/or increasing resilience. While modalities such as mindfulness-based stress reduction show promise, further studies with a cohort of midwives should be conducted. These studies should include interventions aimed at addressing the needs of midwives to improve psychological outcomes related to employment-related stress on a global scale and specific to each health care context. © 2017 by the American College of Nurse-Midwives.

Differential Impact of Stress Reduction Programs upon Ambulatory Blood Pressure among African American Adolescents: Influences of Endothelin-1 Gene and Chronic Stress Exposure

Directory of Open Access Journals (Sweden)

Mathew J. Gregoski

2012-01-01

Full Text Available Stress-activated gene × environment interactions may contribute to individual variability in blood pressure reductions from behavioral interventions. We investigated effects of endothelin-1 (ET-1 LYS198ASN SNP and discriminatory stress exposure upon impact of 12-week behavioral interventions upon ambulatory BP (ABP among 162 prehypertensive African American adolescents. Following genotyping, completion of questionnaire battery, and 24-hour ABP monitoring, participants were randomized to health education control (HEC, life skills training (LST, or breathing awareness meditation (BAM. Postintervention ABP was obtained. Significant three-way interactions on ABP changes indicated that among ET-1 SNP carriers, the only group to show reductions was BAM from low chronic stress environments. Among ET-1 SNP noncarriers, under low chronic stress exposure, all approaches worked, especially BAM. Among high stress exposure noncarriers, only BAM resulted in reductions. If these preliminary findings are replicated via ancillary analyses of archival databases and then via efficacy trials, selection of behavioral prescriptions for prehypertensives will be edging closer to being guided by individual's underlying genetic and environmental factors incorporating the healthcare model of personalized preventive medicine.

The Effect of Composite Thickness on the Stress Distribution Pattern of Restored Premolar Teeth with Cusp Reduction.

Science.gov (United States)

Panahandeh, Narges; Torabzadeh, Hassan; Ziaee, Nargess; Mahdian, Mina; Tootiaee, Bahman; Ghasemi, Amir

2017-07-01

Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored premolar with cusp reduction. A 3D solid model of a maxillary second premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software. Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth. The model with 2.5 mm cusp reduction exhibited the most even stress distribution. © 2015 by the American College of Prosthodontists.

Chronic light reduction reduces overall resilience to additional shading stress in the seagrass

NARCIS (Netherlands)

Yaakub, S.M.; Chen, E.; Bouma, T.; Erftemeijer, P.L.A.; Todd, P.A.

2014-01-01

Seagrasses have substantial capacity to survive long periods of light reduction, but how acclimation to chronic low light environments may influence their ability to cope with additional stress is poorly understood. This study examines the effect of temporal light reduction by adding two levels of

The sequential pathway between trauma-related symptom severity and cognitive-based smoking processes through perceived stress and negative affect reduction expectancies among trauma exposed smokers.

Science.gov (United States)

Garey, Lorra; Cheema, Mina K; Otal, Tanveer K; Schmidt, Norman B; Neighbors, Clayton; Zvolensky, Michael J

2016-10-01

Smoking rates are markedly higher among trauma-exposed individuals relative to non-trauma-exposed individuals. Extant work suggests that both perceived stress and negative affect reduction smoking expectancies are independent mechanisms that link trauma-related symptoms and smoking. Yet, no work has examined perceived stress and negative affect reduction smoking expectancies as potential explanatory variables for the relation between trauma-related symptom severity and smoking in a sequential pathway model. Methods The present study utilized a sample of treatment-seeking, trauma-exposed smokers (n = 363; 49.0% female) to examine perceived stress and negative affect reduction expectancies for smoking as potential sequential explanatory variables linking trauma-related symptom severity and nicotine dependence, perceived barriers to smoking cessation, and severity of withdrawal-related problems and symptoms during past quit attempts. As hypothesized, perceived stress and negative affect reduction expectancies had a significant sequential indirect effect on trauma-related symptom severity and criterion variables. Findings further elucidate the complex pathways through which trauma-related symptoms contribute to smoking behavior and cognitions, and highlight the importance of addressing perceived stress and negative affect reduction expectancies in smoking cessation programs among trauma-exposed individuals. (Am J Addict 2016;25:565-572). © 2016 American Academy of Addiction Psychiatry.

Clinical experimental stress studies: methods and assessment.

Science.gov (United States)

Bali, Anjana; Jaggi, Amteshwar Singh

2015-01-01

Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Stress induction methods are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these methods are also important for the development of novel pharmacological agents for stress management. The well-described methods to induce stress in humans include the cold pressor test, Trier Social Stress Test, Montreal Imaging Stress Task, Maastricht Acute Stress Test, CO2 challenge test, Stroop test, Paced Auditory Serial Addition Task, noise stress, and Mannheim Multicomponent Stress Test. Stress assessment in humans is done by measuring biochemical markers such as cortisol, cortisol awakening response, dexamethasone suppression test, salivary α-amylase, plasma/urinary norepinephrine, norepinephrine spillover rate, and interleukins. Physiological and behavioral changes such as galvanic skin response, heart rate variability, pupil size, and muscle and/or skin sympathetic nerve activity (microneurography) and cardiovascular parameters such as heart rate, blood pressure, and self-reported anxiety are also monitored to assess stress response. This present review describes these commonly employed methods to induce stress in humans along with stress assessment methods.

The calm mouse: an animal model of stress reduction.

Science.gov (United States)

Gurfein, Blake T; Stamm, Andrew W; Bacchetti, Peter; Dallman, Mary F; Nadkarni, Nachiket A; Milush, Jeffrey M; Touma, Chadi; Palme, Rupert; Di Borgo, Charles Pozzo; Fromentin, Gilles; Lown-Hecht, Rachel; Konsman, Jan Pieter; Acree, Michael; Premenko-Lanier, Mary; Darcel, Nicolas; Hecht, Frederick M; Nixon, Douglas F

2012-05-09

Chronic stress is associated with negative health outcomes and is linked with neuroendocrine changes, deleterious effects on innate and adaptive immunity, and central nervous system neuropathology. Although stress management is commonly advocated clinically, there is insufficient mechanistic understanding of how decreasing stress affects disease pathogenesis. Therefore, we have developed a "calm mouse model" with caging enhancements designed to reduce murine stress. Male BALB/c mice were divided into four groups: control (Cntl), standard caging; calm (Calm), large caging to reduce animal density, a cardboard nest box for shelter, paper nesting material to promote innate nesting behavior, and a polycarbonate tube to mimic tunneling; control exercise (Cntl Ex), standard caging with a running wheel, known to reduce stress; and calm exercise (Calm Ex), calm caging with a running wheel. Calm, Cntl Ex and Calm Ex animals exhibited significantly less corticosterone production than Cntl animals. We also observed changes in spleen mass, and in vitro splenocyte studies demonstrated that Calm Ex animals had innate and adaptive immune responses that were more sensitive to acute handling stress than those in Cntl. Calm animals gained greater body mass than Cntl, although they had similar food intake, and we also observed changes in body composition, using magnetic resonance imaging. Together, our results suggest that the Calm mouse model represents a promising approach to studying the biological effects of stress reduction in the context of health and in conjunction with existing disease models.

Can sickness absence be reduced by stress reduction programs: On the effectiveness of two approaches

NARCIS (Netherlands)

Rhenen, W. van; Blonk, R.W.B.; Schaufeli, W.B.; Dijk, F.J.H. van

2007-01-01

Objectives: The aim of the study was to evaluate the effectiveness of two brief preventive stress reduction programs - a cognitive focused program and a combined intervention of physical exercise and relaxation - on sickness absence in stressed and non-stressed employees working in various jobs in a

Designing, Prototyping and Evaluating Digital Mindfulness Applications: A Case Study of Mindful Breathing for Stress Reduction.

Science.gov (United States)

Zhu, Bin; Hedman, Anders; Feng, Shuo; Li, Haibo; Osika, Walter

2017-06-14

During the past decade, there has been a rapid increase of interactive apps designed for health and well-being. Yet, little research has been published on developing frameworks for design and evaluation of digital mindfulness facilitating technologies. Moreover, many existing digital mindfulness applications are purely software based. There is room for further exploration and assessment of designs that make more use of physical qualities of artifacts. The study aimed to develop and test a new physical digital mindfulness prototype designed for stress reduction. In this case study, we designed, developed, and evaluated HU, a physical digital mindfulness prototype designed for stress reduction. In the first phase, we used vapor and light to support mindful breathing and invited 25 participants through snowball sampling to test HU. In the second phase, we added sonification. We deployed a package of probes such as photos, diaries, and cards to collect data from users who explored HU in their homes. Thereafter, we evaluated our installation using both self-assessed stress levels and heart rate (HR) and heart rate variability (HRV) measures in a pilot study, in order to measure stress resilience effects. After the experiment, we performed a semistructured interview to reflect on HU and investigate the design of digital mindfulness apps for stress reduction. The results of the first phase showed that 22 of 25 participants (88%) claimed vapor and light could be effective ways of promoting mindful breathing. Vapor could potentially support mindful breathing better than light (especially for mindfulness beginners). In addition, a majority of the participants mentioned sound as an alternative medium. In the second phase, we found that participants thought that HU could work well for stress reduction. We compared the effect of silent HU (using light and vapor without sound) and sonified HU on 5 participants. Subjective stress levels were statistically improved with both

Combining walking and relaxation for stress reduction-A randomized cross-over trial in healthy adults.

Science.gov (United States)

Matzer, Franziska; Nagele, Eva; Lerch, Nikolaus; Vajda, Christian; Fazekas, Christian

2018-04-01

Both physical activity and relaxation have stress-relieving potential. This study investigates their combined impact on the relaxation response while considering participants' initial stress level. In a randomized cross-over trial, 81 healthy adults completed 4 types of short-term interventions for stress reduction, each lasting for 1 hr: (1) physical activity (walking) combined with resting, (2) walking combined with balneotherapy, (3) combined resting and balneotherapy, and (4) resting only. Saliva cortisol, blood pressure, state of mood, and relaxation were measured preintervention and postintervention. Stress levels were determined by validated questionnaires. All interventions were associated with relaxation responses in the variables saliva cortisol, blood pressure, state of mood, and subjective relaxation. No significant differences were found regarding the reduction of salivary cortisol (F = 1.30; p = .281). The systolic blood pressure was reduced best when walking was combined with balneotherapy or resting (F = 7.34; p stress levels (n = 25) felt more alert after interventions including balneotherapy, whereas they reported an increase of tiredness when walking was combined with resting (F = 3.20; p = .044). Results suggest that combining physical activity and relaxation (resting or balneotherapy) is an advantageous short-term strategy for stress reduction as systolic blood pressure is reduced best while similar levels of relaxation can be obtained. Copyright © 2017 John Wiley & Sons, Ltd.

Mind magic: a pilot study of preventive mind-body-based stress reduction in behaviorally inhibited and activated children.

Science.gov (United States)

Jellesma, Francine C; Cornelis, Janine

2012-03-01

The aim of this pilot study was to examine a mind-body-based preventive intervention program and to determine relationships between children's behavioral inhibition system (BIS) and behavioral activation system, stress, and stress reduction after the program. Children participated in the program (n=30) or in a control condition (n=24). They filled out questionnaires before and after the program and reported their levels of stress before and after each of the five sessions. The program consisted of weekly sessions. Each session incorporated yoga postures, visualization, and social exercises. Breathing techniques were integrated. Stress reductions were only seen in the intervention group and mainly in children with high BIS--irrespective of their behavioral activation system. The results demonstrate that children with high BIS may benefit from a mind-body-based stress reduction program.

The effect of yoga in stress reduction for dental students performing their first periodontal surgery: A randomized controlled study

Science.gov (United States)

Shankarapillai, Rajesh; Nair, Manju Anathakrishnan; George, Roy

2012-01-01

Context: The dental students experience a lot of stress, which increase when they perform their first surgical procedure. Yoga as an anxiolytic tool in anxiety reduction has been practiced over centuries in India. Aim: To assess the efficacy of yoga in reducing the state trait anxiety of dental students before their first periodontal surgery performance. Settings and Design: A randomized controlled study using a two-way split plot design (pre-post-test) was conducted in the department of periodontics, Pacific Dental College, Udaipur, India. Materials and Methods: One hundred clinical dental students who were ready to perform their first periodontal surgery were selected. Students were randomly assigned to two groups and were given a 60-min session on stress reduction. Group A, yogic intervention group, were instructed to do yoga and their performances were monitored for a period of one week and Group B, control group, were given a lecture on stress reduction without any yoga instructions. The investigator who was unaware of the groups had taken the state trait anxiety score of the students three times a) before assigning them to each group, b) prior to the surgical procedure and c) immediately after the performance of surgery. Statistical Analysis Used: Analyses of variance (ANOVA) by SPSS V.16. Results: The statistical results showed a significant reduction in the VAS and state trait anxiety of Group A compared to Group B (ANOVA; P<0.001). Conclusions: This study concludes that Yogic breathing has a significant effect on the reduction of state trait anxiety level of dental students. PMID:22346066

Who participates in a randomized trial of mindfulness-based stress reduction (MBSR) after breast cancer?

DEFF Research Database (Denmark)

Würtzen, Hanne; Oksbjerg Dalton, Susanne; Kaae Andersen, Klaus

2013-01-01

Danish population-based registries and clinical databases to determine differences in demographics, breast cancer and co-morbidity among 1208 women eligible for a randomized controlled trial (www.clinicaltrials.gov identifier: NCT00990977) of mindfulness-based stress reduction MBSR. RESULTS: Participants......BACKGROUND: Discussion regarding the necessity to identify patients with both the need and motivation for psychosocial intervention is ongoing. Evidence for an effect of mindfulness-based interventions among cancer patients is based on few studies with no systematic enrollment. METHODS: We used...

Reactor power reduction system and method

International Nuclear Information System (INIS)

Bruno, S.J.; Dunn, S.A.; Raber, M.

1978-01-01

A method of operating a nuclear power reactor is disclosed which enables an accelerated power reduction of the reactor without completely shutting the reactor down. The method includes monitoring the incidents which, upon their occurrence, would require an accelerated power reduction in order to maintain the reactor in a safe operation mode; calculating the power reduction required on the occurrence of such an incident; determining a control rod insertion sequence for the normal operation of the reactor, said sequence being chosen to optimize reactor power capability; selecting the number of control rods necessary to respond to the accelerated power reduction demand, said selection being made according to a priority determined by said control rod insertion sequence; and inserting said selected control rods into the reactor core. 11 claims, 13 figures

Effects of mindfulness-based stress reduction on perceived stress and psychological health in patients with tension headache

Directory of Open Access Journals (Sweden)

Abdollah Omidi

2015-01-01

Full Text Available Background: Programs for improving health status of patients with illness related to pain, such as headache, are often still in their infancy. Mindfulness-based stress reduction (MBSR is a new psychotherapy that appears to be effective in treating chronic pain and stress. This study evaluated efficacy of MBSR in treatment of perceived stress and mental health of client who has tension headache. Materials and Methods: This study is a randomized clinical trial. Sixty patients with tension type headache according to the International Headache Classification Subcommittee were randomly assigned to the Treatment As Usual (TAU group or experimental group (MBSR. The MBSR group received eight weekly classmates with 12-min sessions. The sessions were based on MBSR protocol. The Brief Symptom Inventory (BSI and Perceived Stress Scale (PSS were administered in the pre- and posttreatment period and at 3 months follow-up for both the groups. Results: The mean of total score of the BSI (global severity index; GSI in MBSR group was 1.63 ± 0.56 before the intervention that was significantly reduced to 0.73 ± 0.46 and 0.93 ± 0.34 after the intervention and at the follow-up sessions, respectively (P < 0.001. In addition, the MBSR group showed lower scores in perceived stress in comparison with the control group at posttest evaluation. The mean of perceived stress before the intervention was 16.96 ± 2.53 and was changed to 12.7 ± 2.69 and 13.5 ± 2.33 after the intervention and at the follow-up sessions, respectively (P < 0.001. On the other hand, the mean of GSI in the TAU group was 1.77 ± 0.50 at pretest that was significantly reduced to 1.59 ± 0.52 and 1.78 ± 0.47 at posttest and follow-up, respectively (P < 0.001. Also, the mean of perceived stress in the TAU group at pretest was 15.9 ± 2.86 and that was changed to 16.13 ± 2.44 and 15.76 ± 2.22 at posttest and follow-up, respectively (P < 0.001. Conclusion: MBSR could reduce stress and improve

Endogenous reward mechanisms and their importance in stress reduction, exercise and the brain.

Science.gov (United States)

Esch, Tobias; Stefano, George B

2010-06-30

Stress can facilitate disease processes and causes strain on the health care budgets. It is responsible or involved in many human ailments of our time, such as cardiovascular illnesses, particularly related to the psychosocial stressors of daily life, including work. Besides pharmacological or clinical medical treatment options, behavioral stress reduction is much-needed. These latter approaches rely on an endogenous healing potential via life-style modification. Hence, research has suggested different ways and approaches to self-treat stress or buffer against stressors and their impacts. These self-care-centred approaches are sometimes referred to as mind-body medicine or multi-factorial stress management strategies. They consist of various cognitive behavioral techniques, as well as relaxation exercises and nutritional counselling. However, a critical and consistent element of modern effective stress reduction strategies are exercise practices. With regard to underlying neurobiological mechanisms of stress relief, reward and motivation circuitries that are imbedded in the limbic regions of the brain are responsible for the autoregulatory and endogenous processing of stress. Exercise techniques clearly have an impact upon these systems. Thereby, physical activities have a potential to increase mood, i.e., decrease psychological distress by pleasure induction. For doing so, neurobiological signalling molecules such as endogenous morphine and coupled nitric oxide pathways get activated and finely tuned. Evolutionarily, the various activities and autoregulatory pathways are linked together, which can also be demonstrated by the fact that dopamine is endogenously converted into morphine which itself leads to enhanced nitric oxide release by activation of constitutive nitric oxide synthase enzymes. These molecules and mechanisms are clearly stress-reducing.

Stress corrosion evaluation of powder metallurgy aluminum alloy 7091 with the breaking load test method

Science.gov (United States)

Domack, Marcia S.

1987-01-01

The stress corrosion behavior of the P/M aluminum alloy 7091 is evaluated in two overaged heat treatment conditions, T7E69 and T7E70, using an accelerated test technique known as the breaking load test method. The breaking load data obtained in this study indicate that P/M 7091 alloy is highly resistant to stress corrosion in both longitudinal and transverse orientations at stress levels up to 90 percent of the material yield strength. The reduction in mean breaking stress as a result of corrosive attack is smallest for the more overaged T7E70 condition. Details of the test procedure are included.

Effect of stress on NiO reduction in solid oxide fuel cells: A new application of energy-resolved neutron imaging

DEFF Research Database (Denmark)

Makowska, Malgorzata; Strobl, Markus; Lauridsen, Erik Mejdal

2015-01-01

Recently, two new phenomena linking stress field and reduction rates in anode-supported solid oxide fuel cells (SOFCs) have been demonstrated, so-called accelerated creep during reduction and reduction rate enhancement and nucleation due to stress (Frandsen et al., 2014). These complex phenomena...

Effect of abiotic and biotic stress factors analysis using machine learning methods in zebrafish.

Science.gov (United States)

Gutha, Rajasekar; Yarrappagaari, Suresh; Thopireddy, Lavanya; Reddy, Kesireddy Sathyavelu; Saddala, Rajeswara Reddy

2018-03-01

In order to understand the mechanisms underlying stress responses, meta-analysis of transcriptome is made to identify differentially expressed genes (DEGs) and their biological, molecular and cellular mechanisms in response to stressors. The present study is aimed at identifying the effect of abiotic and biotic stress factors, and it is found that several stress responsive genes are common for both abiotic and biotic stress factors in zebrafish. The meta-analysis of micro-array studies revealed that almost 4.7% i.e., 108 common DEGs are differentially regulated between abiotic and biotic stresses. This shows that there is a global coordination and fine-tuning of gene regulation in response to these two types of challenges. We also performed dimension reduction methods, principal component analysis, and partial least squares discriminant analysis which are able to segregate abiotic and biotic stresses into separate entities. The supervised machine learning model, recursive-support vector machine, could classify abiotic and biotic stresses with 100% accuracy using a subset of DEGs. Beside these methods, the random forests decision tree model classified five out of 8 stress conditions with high accuracy. Finally, Functional enrichment analysis revealed the different gene ontology terms, transcription factors and miRNAs factors in the regulation of stress responses. Copyright © 2017 Elsevier Inc. All rights reserved.

Approach to mitigate intergranular stress corrosion cracking and dose rate reduction rate by water chemistry control in Tokai-2

International Nuclear Information System (INIS)

Hisamune, Kenji

2015-01-01

The Japan Atomic Power Company (JAPC) had been working on material replacement and measures to mitigate stress in order to maintain the integrity of the structural material of Tokai-Daini nuclear power plant (Tokai-2, BWR, 1,100 MWe; commercial operation started on November 28, 1978). In addition, as Stress Corrosion Cracking (SCC) environmental mitigation measures, we have been reducing the sulfate ion concentration in the reactor water by improving the regeneration method of the ion exchange resin at condensate purification system. Furthermore, in conducting the SCC environmental mitigation measures by applying hydrogen water chemistry (HWC) and HWC during start-up (HDS), we have been reducing the oxidizing agent concentration in the reactor water. On the other hand, as a plant that has not installed condensate filters, we have been working on feed water iron concentration reduction measures in Tokai-2 as part of the dose reduction measures. Therefore, we have improved condensate demineralizer's ion exchange resin and the ion exchange resin cleaning method using the ARCS (Advanced Resin Cleaning System) in order to improve the iron removal performance of condensate demineralizer. This document reports the improvement effect of the SCC environmental mitigation measures and the dose reduction measures by water chemistry management at Tokai-2. In addition, the dose reduction effect of the recently applied zinc injection, and the Electrochemical Corrosion Potential (ECP) monitoring plan under the On-Line Noble Chemical Addition (OLNC™) to be implemented later shall be introduced. (author)

Mindfulness-based stress reduction for treating chronic headache: A systematic review and meta-analysis.

Science.gov (United States)

Anheyer, Dennis; Leach, Matthew J; Klose, Petra; Dobos, Gustav; Cramer, Holger

2018-01-01

Background Mindfulness-based stress reduction/cognitive therapy are frequently used for pain-related conditions, but their effects on headache remain uncertain. This review aimed to assess the efficacy and safety of mindfulness-based stress reduction/cognitive therapy in reducing the symptoms of chronic headache. Data sources and study selection MEDLINE/PubMed, Scopus, CENTRAL, and PsychINFO were searched to 16 June 2017. Randomized controlled trials comparing mindfulness-based stress reduction/cognitive therapy with usual care or active comparators for migraine and/or tension-type headache, which assessed headache frequency, duration or intensity as a primary outcome, were eligible for inclusion. Risk of bias was assessed using the Cochrane Tool. Results Five randomized controlled trials (two on tension-type headache; one on migraine; two with mixed samples) with a total of 185 participants were included. Compared to usual care, mindfulness-based stress reduction/cognitive therapy did not improve headache frequency (three randomized controlled trials; standardized mean difference = 0.00; 95% confidence interval = -0.33,0.32) or headache duration (three randomized controlled trials; standardized mean difference = -0.08; 95% confidence interval = -1.03,0.87). Similarly, no significant difference between groups was found for pain intensity (five randomized controlled trials; standardized mean difference = -0.78; 95% confidence interval = -1.72,0.16). Conclusions Due to the low number, small scale and often high or unclear risk of bias of included randomized controlled trials, the results are imprecise; this may be consistent with either an important or negligible effect. Therefore, more rigorous trials with larger sample sizes are needed.

Finite Element Analysis for Fatigue Damage Reduction in Metallic Riveted Bridges Using Pre-Stressed CFRP Plates

Directory of Open Access Journals (Sweden)

Elyas Ghafoori

2014-04-01

Full Text Available Many old riveted steel bridges remain operational and require retrofit to accommodate ever increasing demands. Complicating retrofit efforts, riveted steel bridges are often considered historical structures where structural modifications that affect the original construction are to be avoided. The presence of rivets along with preservation requirements often prevent the use of traditional retrofit methods, such as bonding of fiber reinforced composites, or the addition of supplementary steel elements. In this paper, an un-bonded post-tensioning retrofit method is numerically investigated using existing railway riveted bridge geometry in Switzerland. The finite element (FE model consists of a global dynamic model for the whole bridge and a more refined sub-model for a riveted joint. The FE model results include dynamic effects from axle loads and are compared with field measurements. Pre-stressed un-bonded carbon fiber reinforced plastic (CFRP plates will be considered for the strengthening elements. Fatigue critical regions of the bridge are identified, and the effects of the un-bonded post-tensioning method with different pre-stress levels on fatigue susceptibility are explored. With an applied 40% CFRP pre-stress, fatigue damage reductions of more than 87% and 85% are achieved at the longitudinal-to-cross beam connections and cross-beam bottom flanges, respectively.

The effects of a group based stress treatment program (the Kalmia concept) targeting stress reduction and return to work. A randomized, wait-list controlled trial

DEFF Research Database (Denmark)

Netterstrøm, Bo; Friebel, Lene; Ladegaard, Yun Katrine

2012-01-01

Abstract Objective The aim of this study was to evaluate the effects of a group based multidisciplinary stress treatment program on reductions in symptom levels and the return to work (RTW) rate. Methods General practitioners referred 199 patients with persistent work related stress symptoms...... to the project. The inclusion criteria included being employed and being on sick leave. Using a randomized wait- list control design, the participants were randomized into three groups: the intervention group (IG, 70 participants) was treated using the Stress Therapy Concept of Kalmia, which consists...... to the WLCG . Further, the prevalence of depression declined significantly in the IG and the TAUCG compared to the WLCG. Regarding the RTW rate, 66% of the participants in the IG had returned to full time work after three months. This rate was significantly greater than the percentage in the TAUCG (36...

Direct method of design and stress analysis of rotating disks with temperature gradient

Science.gov (United States)

Manson, S S

1950-01-01

A method is presented for the determination of the contour of disks, typified by those of aircraft gas turbines, to incorporate arbitrary elastic-stress distributions resulting from either centrifugal or combined centrifugal and thermal effects. The specified stress may be radial, tangential, or any combination of the two. Use is made of the finite-difference approach in solving the stress equations, the amount of computation necessary in the evolution of a design being greatly reduced by the judicious selection of point stations by the aid of a design chart. Use of the charts and of a preselected schedule of point stations is also applied to the direct problem of finding the elastic and plastic stress distribution in disks of a given design, thereby effecting a great reduction in the amount of calculation. Illustrative examples are presented to show computational procedures in the determination of a new design and in analyzing an existing design for elastic stress and for stresses resulting from plastic flow.

Influence of Carrier Gas Composition on the Stress of Al2O3 Coatings Prepared by the Aerosol Deposition Method

Directory of Open Access Journals (Sweden)

Michael Schubert

2014-08-01

Full Text Available Al2O3 films were prepared by the aerosol deposition method at room temperature using different carrier gas compositions. The layers were deposited on alumina substrates and the film stress of the layer was calculated by measuring the deformation of the substrate. It was shown that the film stress can be halved by using oxygen instead of nitrogen or helium as the carrier gas. The substrates were annealed at different temperature steps to gain information about the temperature dependence of the reduction of the implemented stress. Total relaxation of the stress can already be achieved at 300 °C. The XRD pattern shows crystallite growth and reduction of microstrain while annealing.

Parent Perspectives of Applying Mindfulness-Based Stress Reduction Strategies to Special Education.

Science.gov (United States)

Burke, Meghan M; Chan, Neilson; Neece, Cameron L

2017-06-01

Parents of children with (versus without) intellectual and developmental disabilities report greater stress; such stress may be exacerbated by dissatisfaction with school services, poor parent-school partnerships, and the need for parent advocacy. Increasingly, mindfulness interventions have been used to reduce parent stress. However, it is unclear whether parents apply mindfulness strategies during the special education process to reduce school-related stress. To investigate whether mindfulness may reduce school-related stress, interviews were conducted with 26 parents of children with intellectual and developmental disabilities who completed a mindfulness-based stress reduction intervention. Participants were asked about their stress during meetings with the school, use of mindfulness strategies in communicating with the school, and the impact of such strategies. The majority of parent participants reported: special education meetings were stressful; they used mindfulness strategies during IEP meetings; and such strategies affected parents' perceptions of improvements in personal well-being, advocacy, family-school relationships, and access to services for their children. Implications for future research, policy, and practice are discussed.

Applications of the reduction method

International Nuclear Information System (INIS)

Zimmermann, W.

1987-01-01

A renoramalizable model of quantum field theory involving several independent coupling parameters, λ 0 , ..., λ n and a normalization mass K is considered. If the model involves massive particles a formulation of the renormalization group should be used in which the β-functions are independent of the masses. The aim of the reduction method is to reduce the model to a description in terms of a single coupling parameter. Although the reduction method does not work for the gauge couplings it leads to reasonable mass constraints if applied to the Yukawa and the Higgs couplings. The underlying idea is that - whatever the fundamental interaction if going to be - eventually there is only one coupling which determines all parameters of the standard model. However, one should be skeptical about numerical results in the standard model. For the standard model is only an effective theory, its β-functions are only approximate and change on their lowest order coefficients may have large effects on the reduction solutions

Positive Effects of a Stress Reduction Program Based on Mindfulness Meditation in Brazilian Nursing Professionals: Qualitative and Quantitative Evaluation.

Science.gov (United States)

dos Santos, Teresa Maria; Kozasa, Elisa Harumi; Carmagnani, Isabel Sampaio; Tanaka, Luiza Hiromi; Lacerda, Shirley Silva; Nogueira-Martins, Luiz Antonio

2016-01-01

Mindfulness meditation has been shown to effectively mitigate the negative effects of stress among nursing professionals, but in countries like Brazil, these practices are relatively unexplored. To evaluate the effects of a Stress Reduction Program (SRP) including mindfulness and loving kindness meditation among nursing professionals working in a Brazilian hospital setting. Pilot study with a mixed model using quantitative and qualitative methods was used to evaluate a group of participants. The quantitative data were analyzed at three different time points: pre-intervention, post-intervention, and follow-up. The qualitative data were analyzed at post-intervention. Hospital São Paulo (Brazil). Sample 13 nursing professionals, including nurses, technicians, and nursing assistants working in a hospital. Participants underwent mindfulness and loving kindness meditation during a period of six weeks. Perceived Stress Scale (PSS), Maslach Burnout Inventory (MBI), Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), Satisfaction With Life Scale (SWLS), Self-Compassion Scale (SCS), WHOQOL-BREF quality of life assessment, and Work Stress Scale (WSS). Qualitative data were collected via a group interview following six weeks participation in the SRP. The quantitative analyses revealed a significant reduction (P stress, burnout, depression, and anxiety (trait). These variables showed no significant differences between post-intervention and follow-up scores. The WHOQOL-BREF revealed significant increase (P nursing activities. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of mindfulness-based stress reduction on depression, anxiety, stress and mindfulness in Korean nursing students.

Science.gov (United States)

Song, Yeoungsuk; Lindquist, Ruth

2015-01-01

Nursing students often experience depression, anxiety, stress and decreased mindfulness which may decrease their patient care effectiveness. Mindfulness-based stress reduction (MBSR) effectively reduced depression, anxiety and stress, and increased mindfulness in previous research with other populations, but there is sparse evidence regarding its effectiveness for nursing students in Korea. To examine the effects of MBSR on depression, anxiety, stress and mindfulness in Korean nursing students. A randomized controlled trial. Fifty (50) nursing students at KN University College of Nursing in South Korea were randomly assigned to two groups. Data from 44 students, MBSR (n=21) and a wait list (WL) control (n=23) were analyzed. The MBSR group practiced mindfulness meditation for 2 h every week for 8 weeks. The WL group did not receive MBSR intervention. Standardized self-administered questionnaires of depression, anxiety, stress and mindfulness were administered at the baseline prior to the MBSR program and at completion (at 8 weeks). Compared with WL participants, MBSR participants reported significantly greater decreases in depression, anxiety and stress, and greater increase in mindfulness. A program of MBSR was effective when it was used with nursing students in reducing measures of depression, anxiety and stress, and increasing their mindful awareness. MBSR shows promise for use with nursing students to address their experience of mild depression, anxiety and stress, and to increase mindfulness in academic and clinical work, warranting further study. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of Residual Stresses using Ring Core Method

Directory of Open Access Journals (Sweden)

Holý S.

2010-06-01

Full Text Available The method for measuring residual stresses using ring-core method is described. Basic relations are given for residual stress measurement along the specimen depth and simplified method is described for average residual stress estimation in the drilled layer for known principal stress directions. The estimation of calculated coefficients using FEM is described. Comparison of method sensitivity is made with hole-drilling method. The device for method application is described and an example of experiment is introduced. The accuracy of method is discussed. The influence of strain gauge rosette misalignment to the evaluated residual stresses is performed using FEM.

Awareness of Stress-reduction Interventions: The Impact on Employees' Well-being and Organizational Attitudes.

Science.gov (United States)

Pignata, Silvia; Boyd, Carolyn; Gillespie, Nicole; Provis, Christopher; Winefield, Anthony H

2016-08-01

Employing the social-exchange theoretical framework, we examined the effect of employees' awareness of stress-reduction interventions on their levels of psychological strain, job satisfaction, organizational commitment, perceptions of senior management trustworthiness and procedural justice. We present longitudinal panel data from 869 employees who completed questionnaires at two time points at 13 Australian universities. Our results show that employees who reported an awareness of stress-reduction interventions undertaken at their university scored lower on psychological strain and higher on job satisfaction and commitment than those who were unaware of the interventions. The results suggest that simply the awareness of stress interventions can be linked to positive employee outcomes. The study further revealed that senior management trustworthiness and procedural justice mediate the relationship between awareness and employee outcomes. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

For Whom Does Mindfulness-Based Stress Reduction Work? : Moderating Effects of Personality

NARCIS (Netherlands)

Nyklíček, Ivan; Irrmischer, Mona

2017-01-01

The aim of the present study was to examine potentially moderating effects of personality characteristics regarding changes in anxious and depressed mood associated with Mindfulness-Based Stress Reduction (MBSR), controlling for socio-demographic factors. Meditation-naïve participants from the

Applied methods for mitigation of damage by stress corrosion in BWR type reactors

International Nuclear Information System (INIS)

Hernandez C, R.; Diaz S, A.; Gachuz M, M.; Arganis J, C.

1998-01-01

The Boiling Water nuclear Reactors (BWR) have presented stress corrosion problems, mainly in components and pipes of the primary system, provoking negative impacts in the performance of energy generator plants, as well as the increasing in the radiation exposure to personnel involucred. This problem has caused development of research programs, which are guided to find solution alternatives for the phenomena control. Among results of greater relevance the control for the reactor water chemistry stands out particularly in the impurities concentration and oxidation of radiolysis products; as well as the supervision in the materials selection and the stresses levels reduction. The present work presents the methods which can be applied to diminish the problems of stress corrosion in BWR reactors. (Author)

Endogenous reward mechanisms and their importance in stress reduction, exercise and the brain

OpenAIRE

Esch, Tobias; Stefano, George B.

2010-01-01

Stress can facilitate disease processes and causes strain on the health care budgets. It is responsible or involved in many human ailments of our time, such as cardiovascular illnesses, particularly related to the psychosocial stressors of daily life, including work. Besides pharmacological or clinical medical treatment options, behavioral stress reduction is much-needed. These latter approaches rely on an endogenous healing potential via life-style modification. Hence, research has suggested...

Pre-treatment social anxiety severity moderates the impact of mindfulness-based stress reduction and aerobic exercise.

Science.gov (United States)

Jazaieri, Hooria; Lee, Ihno A; Goldin, Philippe R; Gross, James J

2016-06-01

We examined whether social anxiety severity at pre-treatment would moderate the impact of mindfulness-based stress reduction (MBSR) or aerobic exercise (AE) for generalized social anxiety disorder. MBSR and AE produced equivalent reductions in weekly social anxiety symptoms. Improvements were moderated by pre-treatment social anxiety severity. Mindfulness-based stress reduction (MBSR) and aerobic exercise (AE) are effective in reducing symptoms of social anxiety. Pre-treatment social anxiety severity can be used to inform treatment recommendations. Both MBSR and AE produced equivalent reductions in weekly levels of social anxiety symptoms. MBSR appears to be most effective for patients with lower pre-treatment social anxiety symptom severity. AE appears to be most effective for patients with higher pre-treatment social anxiety symptom severity. © 2015 The British Psychological Society.

Load reduction test method of similarity theory and BP neural networks of large cranes

Science.gov (United States)

Yang, Ruigang; Duan, Zhibin; Lu, Yi; Wang, Lei; Xu, Gening

2016-01-01

Static load tests are an important means of supervising and detecting a crane's lift capacity. Due to space restrictions, however, there are difficulties and potential danger when testing large bridge cranes. To solve the loading problems of large-tonnage cranes during testing, an equivalency test is proposed based on the similarity theory and BP neural networks. The maximum stress and displacement of a large bridge crane is tested in small loads, combined with the training neural network of a similar structure crane through stress and displacement data which is collected by a physics simulation progressively loaded to a static load test load within the material scope of work. The maximum stress and displacement of a crane under a static load test load can be predicted through the relationship of stress, displacement, and load. By measuring the stress and displacement of small tonnage weights, the stress and displacement of large loads can be predicted, such as the maximum load capacity, which is 1.25 times the rated capacity. Experimental study shows that the load reduction test method can reflect the lift capacity of large bridge cranes. The load shedding predictive analysis for Sanxia 1200 t bridge crane test data indicates that when the load is 1.25 times the rated lifting capacity, the predicted displacement and actual displacement error is zero. The method solves the problem that lifting capacities are difficult to obtain and testing accidents are easily possible when 1.25 times related weight loads are tested for large tonnage cranes.

Preliminary comparison of different reduction methods of graphene

Indian Academy of Sciences (India)

The reduction of graphene oxide (GO) is a promising route to bulk produce graphene-based sheets. Different reduction processes result in reduced graphene oxide (RGO) with different properties. In this paper three reduction methods, chemical, thermal and electrochemical reduction, were compared on three aspects ...

Theoretical Research on Thermal Shock Resistance of Ultra-High Temperature Ceramics Focusing on the Adjustment of Stress Reduction Factor

Directory of Open Access Journals (Sweden)

Daining Fang

2013-02-01

Full Text Available The thermal shock resistance of ceramics depends on not only the mechanical and thermal properties of materials, but also the external constraint and thermal condition. So, in order to study the actual situation in its service process, a temperature-dependent thermal shock resistance model for ultra-high temperature ceramics considering the effects of the thermal environment and external constraint was established based on the existing theory. The present work mainly focused on the adjustment of the stress reduction factor according to different thermal shock situations. The influences of external constraint on both critical rupture temperature difference and the second thermal shock resistance parameter in either case of rapid heating or cooling conditions had been studied based on this model. The results show the necessity of adjustment of the stress reduction factor in different thermal shock situations and the limitations of the applicable range of the second thermal shock resistance parameter. Furthermore, the model was validated by the finite element method.

Uranium manufacturing process employing the electrolytic reduction method

International Nuclear Information System (INIS)

Oda, Yoshio; Kazuhare, Manabu; Morimoto, Takeshi.

1986-01-01

The present invention related to a uranium manufacturing process that employs the electrolytic reduction method, but particularly to a uranium manufacturing process that employs an electrolytic reduction method requiring low voltage. The process, in which uranium is obtained by means of the electrolytic method and with uranyl acid as the raw material, is prior art

Importance of silvopastoral systems on caloric stress reduction in tropical livestock productions

Directory of Open Access Journals (Sweden)

Alexander Navas Panadero

2010-06-01

Full Text Available Livestock systems in Colombia have been developed taking concepts and technologies from the green revolution, where gramineous monocrop is privileged over arboreal cover in grazing lands. This model has not taken into account the climatic conditions of the different tropical ecosystems, in which variables as temperature, relative humidity and evaporation can limit the animal´s productive and reproductive efficiency, besides being a risk factor for illness occurrence in the herd. Bos Taurus and Bos Indicus breeds show termoneutral ranges where its genetic potential can be express. However, out of this comfort area animals can enter in caloric stress which in consequence reduces its performance and sometimes can end up causing death. Silvopastoral systems comprise several functions; it contributes to lessen caloric stress since temperature under the tree canopy can reach between 2 and 9°C lower in comparison to open pastures. Differences in temperature reduction have been found among silvopastoral systems and species, being the tree group arrangements and the species with high density canopy, those with superior effect. Interactions among components should be analyzed in order to design systems that incorporate enough arboreal cover to achieve caloric stress reductions, but without affecting forage production in pastures. Silvopastoral systems contribute to improve animal welfare.

The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

Science.gov (United States)

Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

2016-08-01

This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

Comparison of the effects of Korean mindfulness-based stress reduction, walking, and patient education in diabetes mellitus.

Science.gov (United States)

Jung, Hee Young; Lee, Haejung; Park, Jina

2015-12-01

The purpose of this study was to compare the effects of Korean mindfulness-based stress reduction (K-MBSR), walking, and patient education regarding diabetes mellitus (DM) on stress response, glycemic control, and vascular inflammation in patients with diabetes mellitus. A cluster randomized trial including 56 adults with diabetes mellitus (K-MBSR group = 21, walking group = 18, patient education group = 17) was conducted between 13 July and 14 September 2012. The questionnaire included the Diabetes Distress Scale and Perceived Stress Response Inventory. Fasting blood samples were used to measure levels of cortisol, blood glucose, plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (t-PA). There were no statistically significant differences between the effects of K-MBSR, walking, and patient education on stress, glycemic control, or vascular inflammation. However, in the K-MBSR and walking groups, significant reductions in the levels of serum cortisol and PAI-1 were observed. A significant reduction in psychological responses to stress was observed in the walking and patient education groups. Longitudinal studies could provide better insight into the impact of K-MBSR, walking, and patient education on health outcomes in adults with diabetes mellitus. © 2015 Wiley Publishing Asia Pty Ltd.

Methods for predicting isochronous stress-strain curves

International Nuclear Information System (INIS)

Kiyoshige, Masanori; Shimizu, Shigeki; Satoh, Keisuke.

1976-01-01

Isochronous stress-strain curves show the relation between stress and total strain at a certain temperature with time as a parameter, and they are drawn up from the creep test results at various stress levels at a definite temperature. The concept regarding the isochronous stress-strain curves was proposed by McVetty in 1930s, and has been used for the design of aero-engines. Recently the high temperature characteristics of materials are shown as the isochronous stress-strain curves in the design guide for the nuclear energy equipments and structures used in high temperature creep region. It is prescribed that these curves are used as the criteria for determining design stress intensity or the data for analyzing the superposed effects of creep and fatigue. In case of the isochronous stress-strain curves used for the design of nuclear energy equipments with very long service life, it is impractical to determine the curves directly from the results of long time creep test, accordingly the method of predicting long time stress-strain curves from short time creep test results must be established. The method proposed by the authors, for which the creep constitution equations taking the first and second creep stages into account are used, and the method using Larson-Miller parameter were studied, and it was found that both methods were reliable for the prediction. (Kako, I.)

Reductive stress in young healthy individuals at risk of Alzheimer disease.

Science.gov (United States)

Badía, Mari-Carmen; Giraldo, Esther; Dasí, Francisco; Alonso, Dolores; Lainez, Jose M; Lloret, Ana; Viña, Jose

2013-10-01

Oxidative stress is a hallmark of Alzheimer disease (AD) but this has not been studied in young healthy persons at risk of the disease. Carrying an Apo ε4 allele is the major genetic risk factor for AD. We have observed that lymphocytes from young, healthy persons carrying at least one Apo ε4 allele suffer from reductive rather than oxidative stress, i.e., lower oxidized glutathione and P-p38 levels and higher expression of enzymes involved in antioxidant defense, such as glutamylcysteinyl ligase and glutathione peroxidase. In contrast, in the full-blown disease, the situation is reversed and oxidative stress occurs, probably because of the exhaustion of the antioxidant mechanisms just mentioned. These results provide insights into the early events of the progression of the disease that may allow us to find biomarkers of AD at its very early stages. Copyright © 2013 Elsevier Inc. All rights reserved.

van Manen's method and reduction in a phenomenological hermeneutic study.

Science.gov (United States)

Heinonen, Kristiina

2015-03-01

To describe van Manen's method and concept of reduction in a study that used a phenomenological hermeneutic approach. Nurse researchers have used van Manen's method in different ways. Participants' lifeworlds are described in depth, but descriptions of reduction have been brief. The literature and knowledge review and manual search of research articles. Databases Web Science, PubMed, CINAHL and PsycINFO, without applying a time period, to identify uses of van Manen's method. This paper shows how van Manen's method has been used in nursing research and gives some examples of van Manen's reduction. Reduction enables us to conduct in-depth phenomenological hermeneutic research and understand people's lifeworlds. As there are many variations in adapting reduction, it is complex and confusing. This paper contributes to the discussion of phenomenology, hermeneutic study and reduction. It opens up reduction as a method for researchers to exploit.

Development of an on-site measurement method for residual stress in primary system piping of nuclear power plants

International Nuclear Information System (INIS)

Maekawa, Akira; Takahashi, Shigeru; Fujiwara, Masaharu

2014-01-01

In residual stress measurement for large-scale pipes and vessels in high radiation areas and highly contaminated areas of nuclear plants, it is difficult to bring the radioactivated pipes and vessels out of the areas as they are. If they can brought out, it is very burdensome to handle them for the measurement. Development of an on-site measurement method of residual stress which can be quickly applied and has sufficient measurement accuracy is desirable. In this study, a new method combining an electric discharge skim-cut method with a microscopic strain measurement method using markers was proposed to realize the on-site residual stress measurement on pipes in high radiation areas and highly contaminated areas. In the electric discharge skim-cut method, a boat-type sample is skimmed out of a pipe outer/inner surface using electric discharge machining and released residual stress is measured. The on-site measurement of residual stress by the method can be done using a small, portable electric discharge machine. In the microscopic strain measurement method using markers, the residual stress is estimated by microscopic measurement of the distance between markers after the stress release. The combination of both methods can evaluate the residual stress with the same accuracy as conventional methods offer and it can achieve reduction of radiation exposure in the measurement because the work is done simply and rapidly. In this study, the applicability of the electric discharge skim-cut method was investigated because the applicability of the microscopic strain measurement method using markers was confirmed previously. The experimental examination clarified the applicable conditions for the residual stress measurement with the same accuracy as the conventional methods. Furthermore, the electric discharge machining conditions using pure water as the machining liquid was found to eliminate the amount of liquid radioactive waste completely. (author)

Mindfulness Based Stress Reduction for Academic Evaluation Anxiety: A Naturalistic Longitudinal Study

Science.gov (United States)

Dundas, Ingrid; Thorsheim, Torbjørn; Hjeltnes, Aslak; Binder, Per Einar

2016-01-01

Mindfulness based stress reduction (MBSR) for academic evaluation anxiety and self-confidence in 70 help-seeking bachelor's and master's students was examined. A repeated measures analysis of covariance on the 46 students who completed pretreatment and posttreatment measures (median age = 24 years, 83% women) showed that evaluation anxiety and…

Standard test method for determining residual stresses by the hole-drilling strain-gage method

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 Residual Stress Determination: 1.1.1 This test method specifies a hole-drilling procedure for determining residual stress profiles near the surface of an isotropic linearly elastic material. The test method is applicable to residual stress profile determinations where in-plane stress gradients are small. The stresses may remain approximately constant with depth (“uniform” stresses) or they may vary significantly with depth (“non-uniform” stresses). The measured workpiece may be “thin” with thickness much less than the diameter of the drilled hole or “thick” with thickness much greater than the diameter of the drilled hole. Only uniform stress measurements are specified for thin workpieces, while both uniform and non-uniform stress measurements are specified for thick workpieces. 1.2 Stress Measurement Range: 1.2.1 The hole-drilling method can identify in-plane residual stresses near the measured surface of the workpiece material. The method gives localized measurements that indicate the...

Effect of fin attachment on thermal stress reduction of exhaust manifold of an off road diesel engine

Institute of Scientific and Technical Information of China (English)

Ali; Akbar; Partoaa; Morteza; Abdolzadeh; Masoud; Rezaeizadeh

2017-01-01

The effect of fin attachment on the thermal stress reduction of exhaust manifold of an off road diesel engine(Komatsu HD325-6) was investigated.For doing this,coupled thermo-fluid-solid analysis of exhaust manifold of the off road diesel engine was carried out.The thermal analysis,including thermal flow,thermal stress,and the thermal deformation of the manifold was investigated.The flow inside the manifold was simulated and then its properties including velocity,pressure,and temperature were obtained.The flow properties were transferred to the solid model and then the thermal stresses and the thermal deformations of the manifold under different operating conditions were calculated.Finally,based on the predicted thermal stresses and thermal deformations of the manifold body shell,two fin types as well as body shell thickness increase were applied in the critical induced thermal stress area of the manifold to reduce the thermal stress and thermal deformation.The results of the above modifications show that the combined modifications,i.e.the thickness increase and the fin attachment,decrease the thermal stresses by up to 28% and the contribution of the fin attachment in this reduction is much higher compared to the shell thickness increase.

Characteristics of people with self-reported stress-precipitated seizures.

Science.gov (United States)

Privitera, Michael; Walters, Michael; Lee, Ikjae; Polak, Emily; Fleck, Adrienne; Schwieterman, Donna; Haut, Sheryl R

2014-12-01

Stress is the most common patient-reported seizure precipitant. We aimed to determine mood and epilepsy characteristics of people who report stress-precipitated seizures. Sequential patients at a tertiary epilepsy center were surveyed about stress as a seizure precipitant. We asked whether acute (lasting minutes-hours) or chronic (lasting days-months) stress was a seizure precipitant, whether stress reduction had been tried, and what effect stress reduction had on seizure frequency. We collected information on antiepileptic drugs, history of depression and anxiety disorder, prior or current treatment for depression or anxiety, and scores on the Neurological Disorders Depression Inventory (NDDI-E) and Generalized Anxiety Disorders-7 (GAD-7) instruments, which are administered at every visit in our Epilepsy Center. We also asked whether respondents thought that they could predict their seizures to determine if stress as a seizure precipitant was correlated with seizure self-prediction. Two hundred sixty-six subjects were included: 219 endorsed stress as a seizure precipitant [STRESS (+)] and 47 did not [STRESS (-)]. Among STRESS (+) subjects, 85% endorsed chronic stress as a seizure precipitant, and 68% endorsed acute stress as a seizure precipitant. In STRESS (+) subjects, 57% had used some type of relaxation or stress reduction method (most commonly yoga, exercise and meditation), and, of those who tried, 88% thought that these methods improved seizures. Among STRESS (-) subjects, 25% had tried relaxation or stress reduction, and 71% thought that seizures improved. Although univariate analysis showed multiple associations with stress as a seizure precipitant, in the multivariable logistic regression, only the GAD-7 score was associated with STRESS (+) (OR = 1.18 [1.03-1.35], p = 0.017). Subjects who reported stress as a seizure precipitant were more likely to report an ability to self-predict seizures (p < 0.001). Stress-precipitated seizures are commonly reported

A Pilot Study of the Psychological Impact of the Mindfulness-Based Stress-Reduction Program On People Who Stutter

NARCIS (Netherlands)

De Veer, S.; Brouwers, A.; Evers, W.; Tomic, W.

2010-01-01

Abstract In general, people who stutter feel hampered in their communication with others and suffer from stress and anxiety when they have to speak. The Mindfulness-Based Stress Reduction (MBSR) program has proved to be successful in reducing stress, fear and anxiety in many studies involving a

Characteristics of internet use as a means of perceived stress reduction in health care students

Directory of Open Access Journals (Sweden)

Hinić Darko

2016-01-01

Full Text Available Previous studies suggest that people use media for instrumental needs, entertainment/leisure or for social gratification. The aim of this study is to identify specific characteristics of Internet use in health care students who use the Internet as a means of perceived stress reduction. The sample included 231 students (m=34%; f=66%, aged (M=22.44; SD=2.09, who were subsequently categorised into two groups according to whether they consciously use the Internet to alleviate the consequences of stressful experiences. The individuals reporting the Internet as a means of perceived stress reduction spend considerably more time online than other Internet users. They also use contents related to entertainment, culture and sex more frequently, as well as social applications and networks. In comparison to others, these participants meet new people and potential partners more often via the Internet, spend more time on their friends' profiles, while using different entertainment applications, most commonly games. The Internet may play a significant role in reducing negative reactions to stressful events; therefore, we may regard cyberspace as a fertile ground for educational, preventive and counselling services. The main limitation to the current study is the sample (only health care students. Future studies should include assessment of perceived stress levels and their relation to study variables.

Dimensionality Reduction Methods: Comparative Analysis of methods PCA, PPCA and KPCA

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Jorge Arroyo-Hernández

2016-01-01

Full Text Available The dimensionality reduction methods are algorithms mapping the set of data in subspaces derived from the original space, of fewer dimensions, that allow a description of the data at a lower cost. Due to their importance, they are widely used in processes associated with learning machine. This article presents a comparative analysis of PCA, PPCA and KPCA dimensionality reduction methods. A reconstruction experiment of worm-shape data was performed through structures of landmarks located in the body contour, with methods having different number of main components. The results showed that all methods can be seen as alternative processes. Nevertheless, thanks to the potential for analysis in the features space and the method for calculation of its preimage presented, KPCA offers a better method for recognition process and pattern extraction

Methods of measuring residual stresses in components

International Nuclear Information System (INIS)

Rossini, N.S.; Dassisti, M.; Benyounis, K.Y.; Olabi, A.G.

2012-01-01

Highlights: ► Defining the different methods of measuring residual stresses in manufactured components. ► Comprehensive study on the hole drilling, neutron diffraction and other techniques. ► Evaluating advantage and disadvantage of each method. ► Advising the reader with the appropriate method to use. -- Abstract: Residual stresses occur in many manufactured structures and components. Large number of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these components. Over the years, different methods have been developed to measure residual stress for different types of components in order to obtain reliable assessment. The various specific methods have evolved over several decades and their practical applications have greatly benefited from the development of complementary technologies, notably in material cutting, full-field deformation measurement techniques, numerical methods and computing power. These complementary technologies have stimulated advances not only in measurement accuracy and reliability, but also in range of application; much greater detail in residual stresses measurement is now available. This paper aims to classify the different residual stresses measurement methods and to provide an overview of some of the recent advances in this area to help researchers on selecting their techniques among destructive, semi destructive and non-destructive techniques depends on their application and the availabilities of those techniques. For each method scope, physical limitation, advantages and disadvantages are summarized. In the end this paper indicates some promising directions for future developments.

Pre-treatment Social Anxiety Severity Moderates the Impact of Mindfulness-Based Stress Reduction and Aerobic Exercise

Science.gov (United States)

Jazaieri, Hooria; Lee, Ihno A.; Goldin, Philippe R.; Gross, James J.

2015-01-01

We examined whether social anxiety severity at pre-treatment would moderate the impact of Mindfulness-Based Stress Reduction (MBSR) or Aerobic Exercise (AE) for generalized social anxiety disorder. MBSR and AE produced equivalent reductions in weekly social anxiety symptoms. Improvements were moderated by pre-treatment social anxiety severity. PMID:25684277

Effects of Mindfulness-Based Stress Reduction on employees’ mental health: A systematic review

Science.gov (United States)

Heerkens, Yvonne; Kuijer, Wietske; van der Heijden, Beatrice; Engels, Josephine

2018-01-01

Objectives The purpose of this exploratory study was to obtain greater insight into the effects of Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT) on the mental health of employees. Methods Using PsycINFO, PubMed, and CINAHL, we performed a systematic review in October 2015 of studies investigating the effects of MBSR and MBCT on various aspects of employees’ mental health. Studies with a pre-post design (i.e. without a control group) were excluded. Results 24 articles were identified, describing 23 studies: 22 on the effects of MBSR and 1 on the effects of MBSR in combination with some aspects of MBCT. Since no study focused exclusively on MBCT, its effects are not described in this systematic review. Of the 23 studies, 2 were of high methodological quality, 15 were of medium quality and 6 were of low quality. A meta-analysis was not performed due to the emergent and relatively uncharted nature of the topic of investigation, the exploratory character of this study, and the diversity of outcomes in the studies reviewed. Based on our analysis, the strongest outcomes were reduced levels of emotional exhaustion (a dimension of burnout), stress, psychological distress, depression, anxiety, and occupational stress. Improvements were found in terms of mindfulness, personal accomplishment (a dimension of burnout), (occupational) self-compassion, quality of sleep, and relaxation. Conclusion The results of this systematic review suggest that MBSR may help to improve psychological functioning in employees. PMID:29364935

Pharmacological reduction of ER stress protects against TDP-43 neuronal toxicity in vivo.

Science.gov (United States)

Vaccaro, Alexandra; Patten, Shunmoogum A; Aggad, Dina; Julien, Carl; Maios, Claudia; Kabashi, Edor; Drapeau, Pierre; Parker, J Alex

2013-07-01

C. elegans and D. rerio expressing mutant TAR DNA Binding Protein 43 (TDP-43) are powerful in vivo animal models for the genetics and pharmacology of amyotrophic lateral sclerosis (ALS). Using these small-animal models of ALS, we previously identified methylene blue (MB) as a potent suppressor of TDP-43 toxicity. Consequently here we investigated how MB might exert its neuroprotective properties and found that it acts through reduction of the endoplasmic reticulum (ER) stress response. We tested other compounds known to be active in the ER unfolded protein response in worms and zebrafish expressing mutant human TDP-43 (mTDP-43). We identified three compounds: salubrinal, guanabenz and a new structurally related compound phenazine, which also reduced paralysis, neurodegeneration and oxidative stress in our mTDP-43 models. Using C. elegans genetics, we showed that all four compounds act as potent suppressors of mTDP-43 toxicity through reduction of the ER stress response. Interestingly, these compounds operate through different branches of the ER unfolded protein pathway to achieve a common neuroprotective action. Our results indicate that protein-folding homeostasis in the ER is an important target for therapeutic development in ALS and other TDP-43-related neurodegenerative diseases. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Effects of mindfulness-based stress reduction on perceived stress and psychological health in patients with tension headache.

Science.gov (United States)

Omidi, Abdollah; Zargar, Fatemeh

2015-11-01

Programs for improving health status of patients with illness related to pain, such as headache, are often still in their infancy. Mindfulness-based stress reduction (MBSR) is a new psychotherapy that appears to be effective in treating chronic pain and stress. This study evaluated efficacy of MBSR in treatment of perceived stress and mental health of client who has tension headache. This study is a randomized clinical trial. Sixty patients with tension type headache according to the International Headache Classification Subcommittee were randomly assigned to the Treatment As Usual (TAU) group or experimental group (MBSR). The MBSR group received eight weekly classmates with 12-min sessions. The sessions were based on MBSR protocol. The Brief Symptom Inventory (BSI) and Perceived Stress Scale (PSS) were administered in the pre- and posttreatment period and at 3 months follow-up for both the groups. The mean of total score of the BSI (global severity index; GSI) in MBSR group was 1.63 ± 0.56 before the intervention that was significantly reduced to 0.73 ± 0.46 and 0.93 ± 0.34 after the intervention and at the follow-up sessions, respectively (P stress in comparison with the control group at posttest evaluation. The mean of perceived stress before the intervention was 16.96 ± 2.53 and was changed to 12.7 ± 2.69 and 13.5 ± 2.33 after the intervention and at the follow-up sessions, respectively (P stress in the TAU group at pretest was 15.9 ± 2.86 and that was changed to 16.13 ± 2.44 and 15.76 ± 2.22 at posttest and follow-up, respectively (P stress and improve general mental health in patients with tension headache.

In situ time-of-flight neutron imaging of NiO-YSZ anode support reduction under influence of stress

DEFF Research Database (Denmark)

Makowska, Malgorzata Grazyna; Strobl, Markus; Lauridsen, Erik M.

2016-01-01

This article reports on in situ macroscopic scale imaging of NiO-YSZ (YSZ is yttria-stabilized zirconia) reduction under applied stress - a phase transition taking place in solid oxide electrochemical cells in a reducing atmosphere of a hydrogen/nitrogen mixture and at operation temperatures of u...... of applying energy-resolved neutron imaging with both approaches to the NiO-YSZ reduction investigation indicate enhancement of the reduction rate due to applied stress, which is consistent with the results of the authors’ previous research....

Minimization of Residual Stress in an Al-Cu Alloy Forged Plate by Different Heat Treatments

Science.gov (United States)

Dong, Ya-Bo; Shao, Wen-Zhu; Jiang, Jian-Tang; Zhang, Bao-You; Zhen, Liang

2015-06-01

In order to improve the balance of mechanical properties and residual stress, various quenching and aging treatments were applied to Al-Cu alloy forged plate. Residual stresses determined by the x-ray diffraction method and slitting method were compared. The surface residual stress measured by x-ray diffraction method was consistent with that measured by slitting method. The residual stress distribution of samples quenched in water with different temperatures (20, 60, 80, and 100 °C) was measured, and the results showed that the boiling water quenching results in a 91.4% reduction in residual stress magnitudes compared with cold water quenching (20 °C), but the tensile properties of samples quenched in boiling water were unacceptably low. Quenching in 80 °C water results in 75% reduction of residual stress, and the reduction of yield strength is 12.7%. The residual stress and yield strength level are considerable for the dimensional stability of aluminum alloy. Quenching samples into 30% polyalkylene glycol quenchants produced 52.2% reduction in the maximum compressive residual stress, and the reduction in yield strength is 19.7%. Moreover, the effects of uphill quenching and thermal-cold cycling on the residual stress were also investigated. Uphill quenching and thermal-cold cycling produced approximately 25-40% reduction in residual stress, while the effect on tensile properties is quite slight.

Phase Transition Mapping by Means of Neutron Imaging in SOFC Anode Supports During Reduction Under Applied Stress

DEFF Research Database (Denmark)

Makowska, Malgorzata; Strobl, M.; Lauridsen, E. M.

2015-01-01

Mechanical and electrochemical performance of layers composed of Ni-YSZ cermet in solid oxide fuel and electrolysis cells (SOC) depends on their microstructure and initial internal stresses. After sintering, the manufacturing conditions, i.e. temperature, atmosphere and loads, can influence...... the microstructure and in particular the internal stresses in the Ni-YSZ layer and thereby the cell performance. Spatially resolved observation of the phase transition during reduction can provide information on how parameters like temperature and external load influence the reaction progress. This information...... is crucial for optimization of the SOC performance. In this work the measurements with energy resolved neutron imaging of the phase transition during the NiOYSZ reduction performed at different temperatures with and without applied load, are presented. The results indicate a link between reduction rate...

Development of thermal stress screening method. Application of green function method

International Nuclear Information System (INIS)

Furuhashi, Ichiro; Shibamoto, Hiroshi; Kasahara, Naoto

2004-01-01

This work was achieved for the development of the screening method of thermal transient stresses in FBR components. We proposed an approximation method for evaluations of thermal stress under variable heat transfer coefficients (non-linear problems) using the Green functions of thermal stresses with constant heat transfer coefficients (linear problems). Detailed thermal stress analyses provided Green functions for a skirt structure and a tube-sheet of Intermediate Heat Exchanger. The upper bound Green functions were obtained by the analyses using those upper bound heat transfer coefficients. The medium and the lower bound Green functions were got by the analyses of those under medium and the lower bound heat transfer coefficients. Conventional evaluations utilized the upper bound Green functions. On the other hand, we proposed a new evaluation method by using the upper bound, medium and the lower bound Green functions. The comparison of above results gave the results as follows. The conventional evaluations were conservative and appropriate for the cases under one fluid thermal transient structure such as the skirt. The conventional evaluations were generally conservative for the complicated structures under two or more fluids thermal transients such as the tube-sheet. But the danger locations could exists for the complicated structures under two or more fluids transients, namely the conventional evaluations were non-conservative. The proposed evaluations gave good estimations for these complicated structures. Though above results, we have made the basic documents of the screening method of thermal transient stresses using the conventional method and the new method. (author)

The Methods of Stress Management and Their Classification

Directory of Open Access Journals (Sweden)

Honchar Mykhailo F.

2017-12-01

Full Text Available The article considers the content and classification of methods of stress management, which provides systematization of their varieties by the number of existing (character, time interval of application, direction of impact, period of action, way of account the interests of employees, level of formation, method of substantiation, content and the allocated new attributes (scale of changes in terms of stress management systems, level of novelty at enterprise, consistency, which allows to choose the appropriate types of such methods in overcoming undesirable deviations that have a significant negative impact on the functioning of economic entities. It has been determined that such methods are formed in the implementing of technology of stress-management; are the result of management activities of the steering subsystem of organization at each level of management; have alternative nature; form an information-management base for the adoption of managerial decisions in terms of the systems of stress administration. It has been specified that, with the assistance of certain methods in terms of stress management systems, managers can track existing and potential problems in the complex and dynamic environment of the organization, identify their relationships, identify «weak signals», adjust goals and tasks of management of critical undesirable deviations, determine indicators and criteria of stress-management, etc.

Methods for evaluation of mechanical stress condition of materials

Directory of Open Access Journals (Sweden)

Mirchev Yordan

2018-01-01

Full Text Available Primary attention is given to the following methods: method by drilling cylindrical holes (drill method and integrated ultrasonic method using volume (longitudinal and transverse, surface, and sub-surface waves. Drill method allows determination of residual mechanical stress in small depth of material surfaces, assessing type, size, and orientation of principal stresses. For the first time, parallel studies are carried out of mechanical stress in materials using the electroacoustic effect of volume, surface and sub-surface waves on the one hand, and effective mechanical stresses on the other. The experimental results present electroacoustic coefficients for different types of waves in the material of gas pipeline tube of 243 mm diameter and 14 mm thickness. These are used to evaluate mechanical stresses in pipelines, according to active GOST standards.

The method for measuring residual stress in stainless steel pipes

International Nuclear Information System (INIS)

Shimov, Georgy; Rozenbaum, Mikhail; Serebryakov, Alexandr; Serebryakov, Andrey

2016-01-01

The main reason of appearance and growth of corrosion damages of the nuclear steam generator heat exchanger tubes is the process of stress-corrosion cracking of metal under the influence of residual tensile stress. Methods used in the production for estimating residual stresses (such as a method of ring samples) allow measuring only the average tangential stress of the pipe wall. The method of ring samples does not allow to assess the level of residual stress in the surface layer of the pipe. This paper describes an experimental method for measuring the residual stresses on the pipe surface by etching a thin surface layer of the metal. The construction and working principle of a trial installation are described. The residual stresses in the wall of the tubes 16 × 1.5 mm (steel AISI 321) for nuclear steam generators is calculated. Keywords: heat exchange pipes, stress corrosion cracking, residual stresses, stress distribution, stress measurement.

Mind magic: a pilot study of preventive mind-body-based stress reduction in behaviorally inhibited and activated children

NARCIS (Netherlands)

Jellesma, F.C.; Cornelis, J.

2012-01-01

Purpose of study: The aim of this pilot study was to examine a mind-body-based preventive intervention program and to determine relationships between children's behavioral inhibition system (BIS) and behavioral activation system, stress, and stress reduction after the program. Design of study:

Tailoring diffraction technique Rietveld method on residual stress measurements of cold-can oiled 304 stainless steel plates

International Nuclear Information System (INIS)

Parikin; Killen, P.; Anis, M.

2003-01-01

Tailoring of diffraction technique-Rietveld method on residual stress measurements of cold-canailed stainless steel 304 plates assuming the material is isotopic, the residual stress measurements using X-ray powder diffraction is just performed for a plane lying in a large angle. For anisotropic materials, the real measurements will not be represented by the methods. By Utilizing of all diffraction peaks in the observation region, tailoring diffraction technique-Rietveld analysis is able to cover the limitations. The residual stress measurement using X-ray powder diffraction tailored by Rietveld method, in a series of cold-canailed stainless steel 304 plates deforming; 0, 34, 84, 152, 158, 175, and 196 % reduction in thickness, have been reported. The diffraction data were analyzed by using Rietveld structure refinement method. Also, for all cold-canailed stainless steel 304 plates cuplikans, the diffraction peaks are broader than the uncanailed one, indicating that the strains in these cuplikans are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was calculated. Finally, the average residual stresses in cold-canailed stainless steel 304 plates were shown to be a combination effect of hydrostatic stresses of martensite particles and austenite matrix. The average residual stresses were evaluated from the experimentally determined average lattice strains in each phase. It was found the tensile residual stress in a cuplikan was maximum, reaching 442 MPa, for a cuplikan reducing 34% in thickness and minimum for a 196% cuplikan

Mindfulness-Based Stress Reduction in Women with Overweight or Obesity: A Randomized Clinical Trial.

Science.gov (United States)

Raja-Khan, Nazia; Agito, Katrina; Shah, Julie; Stetter, Christy M; Gustafson, Theresa S; Socolow, Holly; Kunselman, Allen R; Reibel, Diane K; Legro, Richard S

2017-08-01

To evaluate the feasibility and cardiometabolic effects of mindfulness-based stress reduction (MBSR) in women with overweight or obesity. Eighty-six women with BMI ≥ 25 kg/m 2 were randomized to 8 weeks of MBSR or health education and followed for 16 weeks. The primary outcome was the Toronto Mindfulness Scale. Secondary outcomes included the Perceived Stress Scale-10, fasting glucose, and blood pressure. Compared to health education, the MBSR group demonstrated significantly improved mindfulness at 8 weeks (mean change from baseline, 4.5 vs. -1.0; P = 0.03) and significantly decreased perceived stress at 16 weeks (-3.6 vs. -1.3, P = 0.01). In the MBSR group, there were significant reductions in fasting glucose at 8 weeks (-8.9 mg/dL, P = 0.02) and at 16 weeks (-9.3 mg/dL, P = 0.02) compared to baseline. Fasting glucose did not significantly improve in the health education group. There were no significant changes in blood pressure, weight, or insulin resistance in the MBSR group. In women with overweight or obesity, MBSR significantly reduces stress and may have beneficial effects on glucose. Future studies demonstrating long-term cardiometabolic benefits of MBSR will be key for establishing MBSR as an effective tool in the management of obesity. © 2017 The Authors. Obesity published by Wiley Periodicals, Inc. on behalf of The Obesity Society (TOS).

For whom does mindfulness-based stress reduction work? : An examination of moderating effects of personality

NARCIS (Netherlands)

Nyklicek, I.; Irrmischer, M.

2017-01-01

The aim of the present study was to examine potentially moderating effects of personality characteristics regarding changes in anxious and depressed mood associated with Mindfulness-Based Stress Reduction (MBSR), controlling forsociodemographicactors.Meditation-naïvearticipants from the general

Effectiveness of stress-management training in the first trimester of pregnancy on improvement of stress reduction in General Moheb Yas Women Hospital

Directory of Open Access Journals (Sweden)

Marzieh Shirazi

2016-10-01

Method: This randomized clinical trial study was performed on 75 pregnant women in their first trimester of pregnancy. These women were referred to the hospital for regular prenatal care. They were assessed by standard anxiety questioner, using Hamilton anxiety scale. The validity and reliability of questioner were approved by experts in this field. Based on Hamilton Scale, the pregnant women were divided to three groups. Pregnant women with low, moderate and sever level anxiety, had18-25, 25-35, and more than 35 scales respectively. According to the level of their anxiety, women in moderate and sever anxiety, as clinical groups, were arranged for stress management workshop based on mindfulness technique in 60 minutes in 5 session per week. For this experimental group were made available compact disk (CD training for practicing lessons during the week. Mindfulness technique was including: Body scan, setting meditation and passing thought technique. Low anxiety level group, as control group, had regular pregnancy care. The groups didn’t need to medical treatment according to the psychiatrist interview. In the ending of therapy, clinical and control groups were assessed by anxiety scale again. Data were analyzed using the statistical software SPSS version 18, T- test analysis was performed. The IRCT code was IRCT2013081814174N2. Results: In this study, it was demonstrated, the level of anxiety and stress was decreased significantly between women in clinical groups, 27.5 to 14.1 for moderated level stress (p=0.001 and 40.1 to16.6 for high level of stress (p=0.001 respectively.. Conclusion: Based on our findings, psychological intervention has beneficial effect on stress reduction during pregnancy. It have direct influence on maternal health status.

Examining mindfulness-based stress reduction: Perceptions from minority older adults residing in a low-income housing facility

Directory of Open Access Journals (Sweden)

Connolly Amy B

2011-05-01

Full Text Available Abstract Background Mindfulness-based stress reduction (MBSR programs are becoming increasingly common, but have not been studied in low income minority older populations. We sought to understand which parts of MBSR were most important to practicing MBSR members of this population, and to understand whether they apply their training to daily challenges. Methods We conducted three focus groups with 13 current members of an MBSR program. Participants were African American women over the age of 60 in a low-income housing residence. We tape recorded each session and subsequently used inductive content analysis to identify primary themes. Results and discussion Analysis of the focus group responses revealed three primary themes stress management, applying mindfulness, and the social support of the group meditation. The stressors they cited using MBSR with included growing older with physical pain, medical tests, financial strain, and having grandchildren with significant mental, physical, financial or legal hardships. We found that participants particularly used their MBSR training for coping with medical procedures, and managing both depression and anger. Conclusion A reflective stationary intervention delivered in-residence could be an ideal mechanism to decrease stress in low-income older adult's lives and improve their health.

Photosynthesis and yield reductions from wheat stem sawfly (Hymenoptera: Cephidae): interactions with wheat solidness, water stress, and phosphorus deficiency.

Science.gov (United States)

Delaney, Kevin J; Weaver, David K; Peterson, Robert K D

2010-04-01

The impact of herbivory on plants is variable and influenced by several factors. The current study examined causes of variation in the impact of larval stem mining by the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), on spring wheat, Triticum aestivum L. We performed greenhouse experiments over 2 yr to (1) study whether biotic (hollow versus solid stemmed host wheat) and abiotic (water, phosphorus stress) factors interact with C. cinctus stem mining to influence degree of mined stem physiological (photosynthesis) and yield (grain weight) reductions; and (2) determine whether whole plant yield compensatory responses occur to offset stem-mining reductions. Flag leaf photosynthetic reduction was not detected 16-20 d after infestation, but were detected at 40-42 d and doubled from water or phosphorus stresses. Main stem grain weight decreased from 10 to 25% from stem mining, largely due to reductions in grain size, with greater reductions under low phosphorus and/or water levels. Phosphorus-deficient plants without water stress were most susceptible to C. cinctus, more than doubling the grain weight reduction due to larval feeding relative to other water and phosphorus treatments. Two solid stemmed varieties with stem mining had less grain weight loss than a hollow stemmed variety, so greater internal mechanical resistance may reduce larval stem mining and plant yield reductions. Our results emphasize the importance of sufficient water and macronutrients for plants grown in regions impacted by C. cinctus. Also, solid stemmed varieties not only reduce wheat lodging from C. cinctus, they may reduce harvested grain losses from infested stems.

A pilot randomized controlled trial of mindfulness-based stress reduction for caregivers of family members with dementia.

Science.gov (United States)

Brown, Kirk Warren; Coogle, Constance L; Wegelin, Jacob

2016-11-01

The majority of care for those with Alzheimer's disease and other age-related dementias is provided in the home by family members. To date, there is no consistently effective intervention for reducing the significant stress burden of many family caregivers. The present pilot randomized controlled trial tested the efficacy of an adapted, eight-week mindfulness-based stress reduction (MBSR) program, relative to a near structurally equivalent, standard social support (SS) control condition for reducing caregiver stress and enhancing the care giver-recipient relationship. Thirty-eight family caregivers were randomized to MBSR or SS, with measures of diurnal salivary cortisol, and perceived stress, mental health, experiential avoidance, caregiver burden, and relationship quality collected pre- and post-intervention and at three-month follow-up. MBSR participants reported significantly lower levels of perceived stress and mood disturbance at post-intervention relative to SS participants. At three-month follow-up, participants in both treatment conditions reported improvements on several psychosocial outcomes. At follow-up, there were no condition differences on these outcomes, nor did MBSR and SS participants differ in diurnal cortisol response change over the course of the study. Both MBSR and SS showed stress reduction effects, and MBSR showed no sustained neuroendocrine and psychosocial advantages over SS. The lack of treatment condition differences could be attributable to active ingredients in both interventions, and to population-specific and design factors.

Reduction of friction stress of ethylene glycol by attached hydrogen ions

Science.gov (United States)

Li, Jinjin; Zhang, Chenhui; Deng, Mingming; Luo, Jianbin

2014-01-01

In the present work, it is shown that the friction stress of ethylene glycol can decrease by an order of magnitude to achieve superlubricity if there are hydrogen ions attached on the friction surfaces. An ultra-low friction coefficient (μ = 0.004) of ethylene glycol between Si3N4 and SiO2 can be obtained with the effect of hydrogen ions. Experimental result indicates that the hydrogen ions adsorbed on the friction surfaces forming a hydration layer and the ethylene glycol in the contact region forming an elastohydrodynamic film are the two indispensable factors for the reduction of friction stress. The mechanism of superlubricity is attributed to the extremely low shear strength of formation of elastohydrodynamic film on the hydration layer. This finding may introduce a new approach to reduce friction coefficient of liquid by attaching hydrogen ions on friction surfaces. PMID:25428584

Fast Reduction Method in Dominance-Based Information Systems

Science.gov (United States)

Li, Yan; Zhou, Qinghua; Wen, Yongchuan

2018-01-01

In real world applications, there are often some data with continuous values or preference-ordered values. Rough sets based on dominance relations can effectively deal with these kinds of data. Attribute reduction can be done in the framework of dominance-relation based approach to better extract decision rules. However, the computational cost of the dominance classes greatly affects the efficiency of attribute reduction and rule extraction. This paper presents an efficient method of computing dominance classes, and further compares it with traditional method with increasing attributes and samples. Experiments on UCI data sets show that the proposed algorithm obviously improves the efficiency of the traditional method, especially for large-scale data.

[Methods and Applications of Psychological Stress State Assessment].

Science.gov (United States)

Li, Xin; Yang, Yadan; Hou, Yongjie; Chen, Zetao

2015-08-01

In this paper, the response of individual's physiological system under psychological stress state is discussed, and the theoretical support for psychological stress assessment research is provided. The two methods, i.e., the psychological stress assessment of questionnaire and physiological parameter assessment used for current psychological stress assessment are summarized. Then, the future trend of development of psychological stress assessment research is pointed out. We hope that this work could do and provide further support and help to psychological stress assessment studies.

Thermal stresses in long prisms by relaxation methods

International Nuclear Information System (INIS)

Cummins, J.D.

1959-07-01

A general method is presented for calculating the elastic thermal stresses in long prisms which are producing heat and are not solvable by simple analytical methods. The problem of an inverted lattice i.e. an hexagonal coolant passage surrounded by hexagonal fuel elements is considered and the temperature and principal thermal stress distributions evaluated for the particular case of 20% coolant. The maximum thermal stress for this type of fuel element is about the same as the maximum thermal stress in a cylindrical fuel element surrounded by a sea of coolant assuming the existence of the same maximum temperature drop and material properties. (author)

Thermal stresses in long prisms by relaxation methods

Energy Technology Data Exchange (ETDEWEB)

Cummins, J D [Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1959-07-15

A general method is presented for calculating the elastic thermal stresses in long prisms which are producing heat and are not solvable by simple analytical methods. The problem of an inverted lattice i.e. an hexagonal coolant passage surrounded by hexagonal fuel elements is considered and the temperature and principal thermal stress distributions evaluated for the particular case of 20% coolant. The maximum thermal stress for this type of fuel element is about the same as the maximum thermal stress in a cylindrical fuel element surrounded by a sea of coolant assuming the existence of the same maximum temperature drop and material properties. (author)

Asymptotic Method for Cladding Stress Evaluation in PCMI

International Nuclear Information System (INIS)

Kim, Hyungkyu; Kim, Jaeyong; Yoon, Kyungho; Lee, Kanghee; Kang, Heungseok

2014-01-01

A PCMI (Pellet Cladding Mechanical Interaction) failure was first reported in the GETR (General Electric Test Reactor) at Vacellitos in 1963, and such failures are still occurring. Since the high stress values in the cladding tube has been of a crucial concern in PCMI studies, there have been many researches on the stress analysis of a cladding tube pressed by a pellet. Typical works can be found in some references. It has often been assumed, however, that the cracks in the pellet were equally spaced and the pellet was a rigid body. In addition, the friction coefficient was arbitrarily chosen so that a slipping between the pellets and cladding tube could not be logically defined. Moreover, the stress intensification due to the sharp edge of a pellet fragment has never been realistically considered. These problems above drove us to launch a framework of a PCMI study particularly on stress analysis technology to improve the present analysis method incorporating the actual PCMI conditions such as the stress intensification, arbitrary distribution of the pellet cracks, material properties (esp. pellet) and slipping behavior of the pellet/cladding interface. As a first step of this work, this paper introduces an asymptotic method that was originally developed for a stress analysis in the vicinity of a sharp notch of a homogeneous body. The intrinsic reason for applying this method is to simulate the stress singularity that is expected to take place at the sharp edge of a pellet fragment due to cracking during irradiation. As a first attempt of this work, an eigenvalue problem is formulated in the case of adhered contact, and the generalized stress intensity factors are defined and evaluated. Although some works obviously remain to be accomplished, for the present framework on the PCMI analysis (e. g., slipping behaviour, contact force etc.), it was addressed that the asymptotic method can produce the stress values that cause the cladding tube failure in PCMI more

Knowledge Reduction Based on Divide and Conquer Method in Rough Set Theory

Directory of Open Access Journals (Sweden)

Feng Hu

2012-01-01

Full Text Available The divide and conquer method is a typical granular computing method using multiple levels of abstraction and granulations. So far, although some achievements based on divided and conquer method in the rough set theory have been acquired, the systematic methods for knowledge reduction based on divide and conquer method are still absent. In this paper, the knowledge reduction approaches based on divide and conquer method, under equivalence relation and under tolerance relation, are presented, respectively. After that, a systematic approach, named as the abstract process for knowledge reduction based on divide and conquer method in rough set theory, is proposed. Based on the presented approach, two algorithms for knowledge reduction, including an algorithm for attribute reduction and an algorithm for attribute value reduction, are presented. Some experimental evaluations are done to test the methods on uci data sets and KDDCUP99 data sets. The experimental results illustrate that the proposed approaches are efficient to process large data sets with good recognition rate, compared with KNN, SVM, C4.5, Naive Bayes, and CART.

Variance reduction methods applied to deep-penetration problems

International Nuclear Information System (INIS)

Cramer, S.N.

1984-01-01

All deep-penetration Monte Carlo calculations require variance reduction methods. Before beginning with a detailed approach to these methods, several general comments concerning deep-penetration calculations by Monte Carlo, the associated variance reduction, and the similarities and differences of these with regard to non-deep-penetration problems will be addressed. The experienced practitioner of Monte Carlo methods will easily find exceptions to any of these generalities, but it is felt that these comments will aid the novice in understanding some of the basic ideas and nomenclature. Also, from a practical point of view, the discussions and developments presented are oriented toward use of the computer codes which are presented in segments of this Monte Carlo course

Active sound reduction system and method

NARCIS (Netherlands)

2016-01-01

The present invention refers to an active sound reduction system and method for attenuation of sound emitted by a primary sound source, especially for attenuation of snoring sounds emitted by a human being. This system comprises a primary sound source, at least one speaker as a secondary sound

The use of Stress Tensor Discriminator Faults in separating heterogeneous fault-slip data with best-fit stress inversion methods. II. Compressional stress regimes

Science.gov (United States)

Tranos, Markos D.

2018-02-01

Synthetic heterogeneous fault-slip data as driven by Andersonian compressional stress tensors were used to examine the efficiency of best-fit stress inversion methods in separating them. Heterogeneous fault-slip data are separated only if (a) they have been driven by stress tensors defining 'hybrid' compression (R constitute a necessary discriminatory tool for the establishment and comparison of two compressional stress tensors determined by a best-fit stress inversion method. The best-fit stress inversion methods are not able to determine more than one 'real' compressional stress tensor, as far as the thrust stacking in an orogeny is concerned. They can only possibly discern stress differences in the late-orogenic faulting processes, but not between the main- and late-orogenic stages.

Preliminary comparison of different reduction methods of graphene ...

Indian Academy of Sciences (India)

diverse applications and developing a simple, green, and efficient method for the mass production of ... properties of graphene have driven the search to find methods ... Chemical reduction of GO sheets has been performed with ... efficient method for the mass production of graphene. 2. ... temperature was raised to 35.

Effects of Muscle-Specific Oxidative Stress on Cytochrome c Release and Oxidation-Reduction Potential Properties.

Science.gov (United States)

Ke, Yiling; Mitacek, Rachel M; Abraham, Anupam; Mafi, Gretchen G; VanOverbeke, Deborah L; DeSilva, Udaya; Ramanathan, Ranjith

2017-09-06

Mitochondria play a significant role in beef color. However, the role of oxidative stress in cytochrome c release and mitochondrial degradation is not clear. The objective was to determine the effects of display time on cytochrome c content and oxidation-reduction potential (ORP) of beef longissimus lumborum (LL) and psoas major (PM) muscles. PM discolored by day 3 compared with LL. On day 0, mitochondrial content and mitochondrial oxygen consumption were greater in PM than LL. However, mitochondrial content and oxygen consumption were lower (P stress can affect cytochrome c release and ORP changes.

Effect of volume loading on the Frank-Starling relation during reductions in central blood volume in heat-stressed humans

DEFF Research Database (Denmark)

Bundgaard-Nielsen, Morten; Wilson, T E; Seifert, Thomas

2010-01-01

During reductions in central blood volume while heat stressed, a greater decrease in stroke volume (SV) for a similar decrease in ventricular filling pressure, compared to normothermia, suggests that the heart is operating on a steeper portion of a Frank-Starling curve. If so, volume loading...... of heat-stressed individuals would shift the operating point to a flatter portion of the heat stress Frank-Starling curve thereby attenuating the reduction in SV during subsequent decreases in central blood volume. To investigate this hypothesis, right heart catheterization was performed in eight males...... from whom pulmonary capillary wedge pressure (PCWP), central venous pressure and SV (via thermodilution) were obtained while central blood volume was reduced via lower-body negative pressure (LBNP) during normothermia, whole-body heating (increase in blood temperature 1 degrees C), and during whole...

Memantine prevents cardiomyocytes nuclear size reduction in the left ventricle of rats exposed to cold stress

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Adriano Meneghini

2009-01-01

Full Text Available OBJECTIVES: Memantine is an N-methyl-d-aspartate (NMDA glutamate receptor antagonist used to treat Alzheimer's disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress. METHOD: We used male EPM-Wistar rats (n=40 divided into 4 groups: 1 Matched control (CON; 2 Memantine-treated rats (MEM; 3 Rats undergoing induced hypothermia (IH and 4 Rats undergoing induced hypothermia that were also treated with memantine (IHM. Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of - 8ºC on the last day of the study. RESULTS: The MEM group had the largest cardiomyocyte nuclear size (151 ± 3.5 μm³ vs. CON: 142 ± 2.3 μm³; p<0.05, while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 ± 2.9 μm³ compared to the IH group (108 ± 1.7 μm³; p<0.05. CONCLUSION: Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress.

For Whom Does Mindfulness-Based Stress Reduction Work? Moderating Effects of Personality.

Science.gov (United States)

Nyklíček, Ivan; Irrmischer, Mona

2017-01-01

The aim of the present study was to examine potentially moderating effects of personality characteristics regarding changes in anxious and depressed mood associated with Mindfulness-Based Stress Reduction (MBSR), controlling for socio-demographic factors. Meditation-naïve participants from the general population self-presenting with psychological stress complaints ( n  = 167 participants, 70% women, mean age 45.8 ± 9.3 years) were assessed in a longitudinal investigation of change in mood before and after the intervention and at a 3-month follow-up. Participants initially scoring high on neuroticism showed stronger decreases in both anxious and depressed mood (both p  moderating effects, when controlled for baseline mood. Only neuroticism showed to be associated with delayed benefit. Results are discussed in the context of findings from similar research using more traditional cognitive-behavioral interventions.

Changing stress levels through gaining information on stress

Directory of Open Access Journals (Sweden)

S.N. Madu

2002-09-01

Full Text Available Objective: The aim of this research was to find out the effect of the Information Phase of a Stress Management Program (SMP on the perceptions of participants about their stress levels. Method: A total sample of 100 workers (nursing staff, private business men and women, laboratory assistants, the protective services [foreman and security staff], as well as people in human resources departments took part in this study. All the participants were from the Northern and Gauteng Provinces in South Africa. The Combined Hassles and Uplifts Scale (Folkman & Lazarus, 1989 was used as an instrument to measure the perceived stress level of participants in a SMP. Result: A significant reduction in stress levels was achieved among those who received the Information Phase of the SMP only, as well as those who received the whole stress management techniques. There was no significant difference between the amount of reduction in perceived stress-levels achieved among those that received the Information Phase of the SMP only, compared to that of those who received the whole techniques. Conclusion: The authors conclude that where the resources are limited, only the information phase of a SMP may be given to desiring clients. That should help to save time and money spent on participating in SMPs. This should however not discourage the use of the whole SPM, where affordable. Keywords: Stress Management Programs, Information Phase, Perception, Stress Level.

Application of the photoelastic experimental hybrid method with new numerical method to the high stress distribution

International Nuclear Information System (INIS)

Hawong, Jai Sug; Lee, Dong Hun; Lee, Dong Ha; Tche, Konstantin

2004-01-01

In this research, the photoelastic experimental hybrid method with Hook-Jeeves numerical method has been developed: This method is more precise and stable than the photoelastic experimental hybrid method with Newton-Rapson numerical method with Gaussian elimination method. Using the photoelastic experimental hybrid method with Hook-Jeeves numerical method, we can separate stress components from isochromatics only and stress intensity factors and stress concentration factors can be determined. The photoelastic experimental hybrid method with Hook-Jeeves had better be used in the full field experiment than the photoelastic experimental hybrid method with Newton-Rapson with Gaussian elimination method

Speckle reduction methods in laser-based picture projectors

Science.gov (United States)

Akram, M. Nadeem; Chen, Xuyuan

2016-02-01

Laser sources have been promised for many years to be better light sources as compared to traditional lamps or light-emitting diodes (LEDs) for projectors, which enable projectors having wide colour gamut for vivid image, super brightness and high contrast for the best picture quality, long lifetime for maintain free operation, mercury free, and low power consumption for green environment. A major technology obstacle in using lasers for projection has been the speckle noise caused by to the coherent nature of the lasers. For speckle reduction, current state of the art solutions apply moving parts with large physical space demand. Solutions beyond the state of the art need to be developed such as integrated optical components, hybrid MOEMS devices, and active phase modulators for compact speckle reduction. In this article, major methods reported in the literature for the speckle reduction in laser projectors are presented and explained. With the advancement in semiconductor lasers with largely reduced cost for the red, green and the blue primary colours, and the developed methods for their speckle reduction, it is hoped that the lasers will be widely utilized in different projector applications in the near future.

Yield Stress Reduction of DWPF Melter Feed Slurries

International Nuclear Information System (INIS)

Stone, M.E.; Smith, M.E.

2007-01-01

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides and soluble sodium salts. The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed slurries be reduced. Changing the glass former added during pretreatment from an irregularly shaped glass frit to nearly spherical beads was evaluated. The evaluation required a systems approach which included evaluations of the effectiveness of beads in reducing the melter feed yield stress as well as evaluations of the processing impacts of changing the frit morphology. Processing impacts of beads include changing the settling rate of the glass former (which effects mixing and sampling of the melter feed slurry and the frit addition equipment) as well as impacts on the melt behavior due to decreased surface area of the beads versus frit. Beads were produced from the DWPF process frit by fire polishing. The frit was allowed to free fall through a flame

Neutron stress measurement using image plate and the cos α method

International Nuclear Information System (INIS)

Sasaki, Toshihiko; Hirose, Yukio; Minakawa, Nobuaki; Morii, Yukio

2004-01-01

A new type of the neutron stress measurement method, in which the stress is determined by the cos α method, was studied. A neutron image plate was used in this study for detecting the diffraction image. Steel specimens of 5 mm thickness were used for the tensile stress test. The stresses obtain from the experiment showed one-to-one ratio with respect to the applied stresses, though the misfit stress of about 400 MPa was also observed in the result. A simple correction technique for calibrating raw data was proposed to obtain the true stress. A simulation study was carried out to check the experimental result on the peak positions in the diffraction ring and the stress calculation by the cos α method. (author)

Critical wall shear stress for the EHEDG test method

DEFF Research Database (Denmark)

Jensen, Bo Boye Busk; Friis, Alan

2004-01-01

In order to simulate the results of practical cleaning tests on closed processing equipment, based on wall shear stress predicted by computational fluid dynamics, a critical wall shear stress is required for that particular cleaning method. This work presents investigations that provide a critical...... wall shear stress of 3 Pa for the standardised EHEDG cleaning test method. The cleaning tests were performed on a test disc placed in a radial flowcell assay. Turbulent flow conditions were generated and the corresponding wall shear stresses were predicted from CFD simulations. Combining wall shear...... stress predictions from a simulation using the low Re k-epsilon and one using the two-layer model of Norris and Reynolds were found to produce reliable predictions compared to empirical solutions for the ideal flow case. The comparison of wall shear stress curves predicted for the real RFC...

Participation in mindfulness-based stress reduction is not associated with reductions in emotional eating or uncontrolled eating.

Science.gov (United States)

Kearney, David J; Milton, Meredith L; Malte, Carol A; McDermott, Kelly A; Martinez, Michelle; Simpson, Tracy L

2012-06-01

The adverse health effects and increasing prevalence of obesity in the United States make interventions for obesity a priority in health research. Diet-focused interventions generally do not result in lasting reductions in weight. Behavioral interventions that increase awareness of eating cues and satiety have been postulated to result in healthier eating habits. We hypothesized that participation in a program called mindfulness-based stress reduction (MBSR) would positively influence the eating behaviors and nutritional intake of participants through changes in emotional eating (EE), uncontrolled eating (UE), and type and quantity of food consumed. Forty-eight veterans at a large urban Veterans Administration medical center were assessed before MBSR, after MBSR, and 4 months later. For all participants (N = 48), MBSR participation was not associated with significant changes in EE or UE. In addition, there were no significant differences in the intake of energy, fat, sugar, fruit, or vegetables at either follow-up time point as compared with baseline. Enhanced mindfulness skills and reduced depressive symptoms were seen over time with medium to large effect sizes. Changes in mindfulness skills were significantly and negatively correlated with changes in EE and UE over time. Overall, there was no evidence that participation in MBSR was associated with beneficial changes in eating through reductions in disinhibited eating or significant changes in dietary intake. Randomized studies are needed to further define the relationship between mindfulness program participation and eating behaviors. Published by Elsevier Inc.

Biomarkers of Resilience in Stress Reduction for Caregivers of Alzheimer's Patients.

Science.gov (United States)

Ho, Lap; Bloom, Patricia A; Vega, Joan G; Yemul, Shrishailam; Zhao, Wei; Ward, Libby; Savage, Evan; Rooney, Robert; Patel, Divyen H; Pasinetti, Giulio Maria

2016-06-01

Caregiving for a dementia patient is associated with increased risk of psychological and physical health problems. We investigated whether a mindfulness-based stress reduction (MBSR) training course for caregivers that closely models the MBSR curriculum originally established by the Center of Mindfulness at the University of Massachusetts may improve the psychological resilience of non-professional caregivers of Alzheimer's disease patients. Twenty adult non-professional caregivers of dementia patients participated in an 8-week MBSR training course. Caregiver stress, depression, burden, grief, and gene expression profiles of blood mononuclear cells were assessed at baseline and following MBSR. MBSR training significantly improved the psychological resilience of some of the caregivers. We identified predictive biomarkers whose expression is associated with the likelihood of caregivers to benefit from MBSR, and biomarkers whose expression is associated with MBSR psychological benefits. Our biomarker studies provide insight into the mechanisms of health benefits of MBSR and a basis for developing a personalized medicine approach for applying MBSR for promoting psychological and cognitive resilience in caregivers of dementia patients.

Dimension reduction methods for microarray data: a review

Directory of Open Access Journals (Sweden)

Rabia Aziz

2017-03-01

Full Text Available Dimension reduction has become inevitable for pre-processing of high dimensional data. “Gene expression microarray data” is an instance of such high dimensional data. Gene expression microarray data displays the maximum number of genes (features simultaneously at a molecular level with a very small number of samples. The copious numbers of genes are usually provided to a learning algorithm for producing a complete characterization of the classification task. However, most of the times the majority of the genes are irrelevant or redundant to the learning task. It will deteriorate the learning accuracy and training speed as well as lead to the problem of overfitting. Thus, dimension reduction of microarray data is a crucial preprocessing step for prediction and classification of disease. Various feature selection and feature extraction techniques have been proposed in the literature to identify the genes, that have direct impact on the various machine learning algorithms for classification and eliminate the remaining ones. This paper describes the taxonomy of dimension reduction methods with their characteristics, evaluation criteria, advantages and disadvantages. It also presents a review of numerous dimension reduction approaches for microarray data, mainly those methods that have been proposed over the past few years.

Variance Reduction Techniques in Monte Carlo Methods

NARCIS (Netherlands)

Kleijnen, Jack P.C.; Ridder, A.A.N.; Rubinstein, R.Y.

2010-01-01

Monte Carlo methods are simulation algorithms to estimate a numerical quantity in a statistical model of a real system. These algorithms are executed by computer programs. Variance reduction techniques (VRT) are needed, even though computer speed has been increasing dramatically, ever since the

Reductive methods for isotopic labeling of antibiotics

International Nuclear Information System (INIS)

Champney, W.S.

1989-01-01

Methods for the reductive methylation of the amino groups of eight different antibiotics using 3 HCOH or H 14 COH are presented. The reductive labeling of an additional seven antibiotics by NaB 3 H 4 is also described. The specific activity of the methyl-labeled drugs was determined by a phosphocellulose paper binding assay. Two quantitative assays for these compounds based on the reactivity of the antibiotic amino groups with fluorescamine and of the aldehyde and ketone groups with 2,4-dinitrophenylhydrazine are also presented. Data on the cellular uptake and ribosome binding of these labeled compounds are also presented

Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR

Science.gov (United States)

Lee, Lik Chuan; Zhihong, Zhang; Hinson, Andrew; Guccione, Julius M.

2013-01-01

Injection of Algisyl-LVR, a treatment under clinical development, is intended to treat patients with dilated cardiomyopathy. This treatment was recently used for the first time in patients who had symptomatic heart failure. In all patients, cardiac function of the left ventricle (LV) improved significantly, as manifested by consistent reduction of the LV volume and wall stress. Here we describe this novel treatment procedure and the methods used to quantify its effects on LV wall stress and function. Algisyl-LVR is a biopolymer gel consisting of Na+-Alginate and Ca2+-Alginate. The treatment procedure was carried out by mixing these two components and then combining them into one syringe for intramyocardial injections. This mixture was injected at 10 to 19 locations mid-way between the base and apex of the LV free wall in patients. Magnetic resonance imaging (MRI), together with mathematical modeling, was used to quantify the effects of this treatment in patients before treatment and at various time points during recovery. The epicardial and endocardial surfaces were first digitized from the MR images to reconstruct the LV geometry at end-systole and at end-diastole. Left ventricular cavity volumes were then measured from these reconstructed surfaces. Mathematical models of the LV were created from these MRI-reconstructed surfaces to calculate regional myofiber stress. Each LV model was constructed so that 1) it deforms according to a previously validated stress-strain relationship of the myocardium, and 2) the predicted LV cavity volume from these models matches the corresponding MRI-measured volume at end-diastole and end-systole. Diastolic filling was simulated by loading the LV endocardial surface with a prescribed end-diastolic pressure. Systolic contraction was simulated by concurrently loading the endocardial surface with a prescribed end-systolic pressure and adding active contraction in the myofiber direction. Regional myofiber stress at end-diastole and

The study on evaluation method for primary stress of 3-D structure

International Nuclear Information System (INIS)

Sadahiro, Daisuke; Shibamoto, Hiroshi; Nagashima, Hideaki; Inoue, Kazuhiko; Kasahara, Naoto

2005-01-01

This paper describes an evaluation method of primary stress in 3-D structures. In 'Design by Analysis' for nuclear components, the stresses in structures are classified into the primary and the secondary stresses. The primary stress in axisymmetric structures can be evaluated by linearization of stress distribution in the specified section, but it is difficult to define the evaluation section in the 3-D structures, and to evaluate the primary stress with the conventional procedure. From this reason, the alternative evaluation method is needed. In this paper, the evaluation method of primary stress in 3-D structures is presented utilizing the feature of primary stress that is independent from stress re-distribution. (author)

Posttraumatic stress symptoms and tobacco abstinence effects in a non-clinical sample: evaluating the mediating role of negative affect reduction smoking expectancies.

Science.gov (United States)

Langdon, Kirsten J; Leventhal, Adam M

2014-11-01

The relation between posttraumatic stress symptoms and smoking is well documented but poorly understood. The present investigation sought to evaluate the impact of posttraumatic stress symptoms on subjective and behavioral tobacco abstinence effects both directly and indirectly through negative affect reduction smoking outcome expectancies. Participants included 275 (68.7% male; Mage =43.9, 10+ cig/day) adult non-treatment seeking smokers, who attended two counterbalanced laboratory sessions (16 h of smoking deprivation vs ad libitum smoking), during which they completed self-report measures of withdrawal symptoms and mood followed by a smoking lapse task in which they could earn money for delaying smoking and purchase cigarettes to smoke. Results supported a mediational pathway whereby higher baseline symptoms of posttraumatic stress predicted greater endorsement of expectancies that smoking will effectively reduce negative affect, which in turn predicted greater abstinence-provoked exacerbations in nicotine withdrawal symptoms and negative affect. Posttraumatic stress symptoms also predicted number of cigarettes purchased independent of negative affect reduction expectancies, but did not predict delaying smoking for money. Findings highlight tobacco abstinence effects as a putative mechanism underlying posttraumatic stress disorder (PTSD)-smoking comorbidity, indicate an important mediating role of beliefs for smoking-induced negative affect reduction, and shed light on integrated treatment approaches for these two conditions. © The Author(s) 2014.

Analysis of Drag Reduction Methods and Mechanisms of Turbulent

Directory of Open Access Journals (Sweden)

Gu Yunqing

2017-01-01

Full Text Available Turbulent flow is a difficult issue in fluid dynamics, the rules of which have not been totally revealed up to now. Fluid in turbulent state will result in a greater frictional force, which must consume great energy. Therefore, it is not only an important influence in saving energy and improving energy utilization rate but also an extensive application prospect in many fields, such as ship domain and aerospace. Firstly, bionic drag reduction technology is reviewed and is a hot research issue now, the drag reduction mechanism of body surface structure is analyzed, such as sharks, earthworms, and dolphins. Besides, we make a thorough study of drag reduction characteristics and mechanisms of microgrooved surface and compliant wall. Then, the relevant drag reduction technologies and mechanisms are discussed, focusing on the microbubbles, the vibrant flexible wall, the coating, the polymer drag reduction additives, superhydrophobic surface, jet surface, traveling wave surface drag reduction, and the composite drag reduction methods. Finally, applications and advancements of the drag reduction technology in turbulence are prospected.

Stress estimation in reservoirs using an integrated inverse method

Science.gov (United States)

Mazuyer, Antoine; Cupillard, Paul; Giot, Richard; Conin, Marianne; Leroy, Yves; Thore, Pierre

2018-05-01

Estimating the stress in reservoirs and their surroundings prior to the production is a key issue for reservoir management planning. In this study, we propose an integrated inverse method to estimate such initial stress state. The 3D stress state is constructed with the displacement-based finite element method assuming linear isotropic elasticity and small perturbations in the current geometry of the geological structures. The Neumann boundary conditions are defined as piecewise linear functions of depth. The discontinuous functions are determined with the CMA-ES (Covariance Matrix Adaptation Evolution Strategy) optimization algorithm to fit wellbore stress data deduced from leak-off tests and breakouts. The disregard of the geological history and the simplified rheological assumptions mean that only the stress field, statically admissible and matching the wellbore data should be exploited. The spatial domain of validity of this statement is assessed by comparing the stress estimations for a synthetic folded structure of finite amplitude with a history constructed assuming a viscous response.

Prolonged non-metabolic heart rate variability reduction as a physiological marker of psychological stress in daily life

NARCIS (Netherlands)

Verkuil, B.; Brosschot, J.F.; Tollenaar, M.S.; Lane, R.D.; Thayer, J.F.

2016-01-01

BACKGROUND Prolonged cardiac activity that exceeds metabolic needs can be detrimental for somatic health. Psychological stress could result in such "additional cardiac activity." PURPOSE In this study, we examined whether prolonged additional reductions in heart rate variability (AddHRVr) can be

Stress measurement by neutron diffraction method. Standard method using angular dispersion method and trial of using neutron IP

International Nuclear Information System (INIS)

Sasaki, Toshihiko; Takago, Shigeki

2016-01-01

This paper outlined a stress measurement method using neutrons, and introduced the application examples to stress measurement for metal-based composite materials. In the angular dispersion type measurement using a steady-state reactor type neutron source, the white beams taken out from a nuclear reactor are monochromatized (wavelength λ is a constant value) with a single crystal monochromator and utilized. As an example of measurement, there was the case as follows: the stress of a sintered material which has been put to practical use as valve seat part for automobiles was measured by the neutron method, and the deformation behavior during load was studied. This study performed neutron diffraction measurement using a residual stress analyzer (RESA: Diffractometer for Residual Stress Analysis) installed at JAEA's experimental reactor JRR-3. As a result, it was found that the stress state of the sintered composite material of Fe-Cr and TiN can be predicted with a micromechanics model. A neutron diffraction ring can be obtained using a neutron image plate (IP), where fine powder of gadolinium (Gd) was incorporated into IP for X-rays, and it can be used as an IP reader in the same way as the case of X-rays. A report has been introduced on the examination results of the highly accurate stress measurement by applying the cos α method devised for X-ray stress measurement to neutron diffraction ring. (A.O.)

A case study of multi-seam coal mine entry stability analysis with strength reduction method.

Science.gov (United States)

Tulu, Ihsan Berk; Esterhuizen, Gabriel S; Klemetti, Ted; Murphy, Michael M; Sumner, James; Sloan, Michael

2016-03-01

In this paper, the advantage of using numerical models with the strength reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under variable topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.

Effect Mycorrhizal Fungi on Reduction of Drought Stress Effect in Some Growth Traits of Sesame (Sesamum indicum L. Genotypes

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esmaeel gholinezhad

2018-02-01

Full Text Available Introduction Sesame (Sesamum indicum plays an important role in human health because of its high oil capacity (47 - 52%.. Arbuscular mycorrhizal symbiosis protects host plants against the detrimental effects of drought stress through mechanisms of drought avoidance. Strategies of drought avoidance in mycorrhizal plants rely on the ability to maintain an adequate hydration status on the level of whole plants as characterized by relative water content. So the aim of current study was to evaluate the symbiosis effect of two different species of mycorrhizae fungi on yield and physiological characteristics of sesame landraces under different drought stress levels in Urmia. Materials and Methods This experiment was conducted in 2014-2015 by using factorial split plot based on randomized complete block design with three replications in the research field of Urmia agricultural high school with 12 Km distance from Urmia. The main plot factor was consisted of different irrigation levels: normal irrigation (irrigation after 70 mm evaporation of crop (ETC, moderate drought stress (irrigation after 90 mm evaporation of crop (ETC and severe drought stress (irrigation after 110 mm evaporation of crop (ETC. Also three levels of Sub plot factors included two species of mycorrhizae fungi Glomus mosseae, Glomus intraradices and no -inoculation (control. Sub-sub plot factorss consisted of eight landraces of sesames (named Jiroft13, Zanjan Tarom landrace, Moghan landrace, Naz of several branches, TC-25,TS-3, Darab 14 and Dashtestan 5. Then Leaf Area Index (LAI, Total Dry Matter (TDM, Leaf relative water content (RWC, Specific leaf area (SLA, Specific leaf weight (SLW, Leaf Area Ratio (LAR, Leaf Weight Ratio (LWR of different landraces calculated using SAS and MSTATC. To compare the means, Tukey's test at 5% probability level was used. Results and Discussion The results of the experiment showed that with increasing the levels of drought stress, RWC, LAI, seed yield

Reduction of Cancer-Specific Thought Intrusions and Anxiety Symptoms With a Stress Management Intervention Among Women Undergoing Treatment for Breast Cancer

Science.gov (United States)

Antoni, Michael H.; Wimberly, Sarah R.; Lechner, Suzanne C.; Kazi, Aisha; Sifre, Tammy; Urcuyo, Kenya R.; Phillips, Kristin; Smith, Roselyn G.; Petronis, Vida M.; Guellati, Sophie; Wells, Kurrie A.; Blomberg, Bonnie; Carver, Charles S.

2017-01-01

Objective After surgery for breast cancer, many women experience anxiety relating to the cancer that can adversely affect quality of life and emotional functioning during the year postsurgery. Symptoms such as intrusive thoughts may be ameliorated during this period with a structured, group-based cognitive behavior intervention. Method A 10-week group cognitive behavior stress management intervention that included anxiety reduction (relaxation training), cognitive restructuring, and coping skills training was tested among 199 women newly treated for stage 0-III breast cancer. They were then followed for 1 year after recruitment. Results The intervention reduced reports of thought intrusion, interviewer ratings of anxiety, and emotional distress across 1 year significantly more than was seen with the control condition. The beneficial effects were maintained well past the completion of adjuvant therapy. Conclusions Structured, group-based cognitive behavior stress management may ameliorate cancer-related anxiety during active medical treatment for breast cancer and for 1 year following treatment. Group-based cognitive behavior stress management is a clinically useful adjunct to offer to women treated for breast cancer. PMID:17012691

Trauma-Informed Mindfulness-Based Stress Reduction for Female Survivors of Interpersonal Violence: Results From a Stage I RCT.

Science.gov (United States)

Kelly, Amber; Garland, Eric L

2016-04-01

This pilot randomized controlled trial evaluated a novel trauma-informed model of mindfulness-based stress reduction (TI-MBSR) as a phase I trauma intervention for female survivors of interpersonal violence (IPV). A community-based sample of women (mean age = 41.5, standard deviation = 14.6) with a history of IPV was randomly assigned to an 8-week TI-MBSR intervention (n = 23) or a waitlist control group (n = 22). Symptoms of posttraumatic stress disorder (PTSD) and depression as well as anxious and avoidant attachment were assessed pre- and postintervention. Relative to the control group, participation in TI-MBSR was associated with statistically and clinically significant decreases in PTSD and depressive symptoms and significant reductions in anxious attachment. Retention in the intervention was high, with most participants completing at least 5 of the 8 sessions for the intervention. Minutes of mindfulness practice per week significantly predicted reductions in PTSD symptoms. TI-MBSR appears to be a promising and feasible phase I intervention for female survivors of interpersonal trauma. © 2016 Wiley Periodicals, Inc.

A novel method for estimating soil precompression stress from uniaxial confined compression tests

DEFF Research Database (Denmark)

Lamandé, Mathieu; Schjønning, Per; Labouriau, Rodrigo

2017-01-01

. Stress-strain curves were obtained by performing uniaxial, confined compression tests on undisturbed soil cores for three soil types at three soil water potentials. The new method performed better than the Gompertz fitting method in estimating precompression stress. The values of precompression stress...... obtained from the new method were linearly related to the maximum stress experienced by the soil samples prior to the uniaxial, confined compression test at each soil condition with a slope close to 1. Precompression stress determined with the new method was not related to soil type or dry bulk density......The concept of precompression stress is used for estimating soil strength of relevance to fieldtraffic. It represents the maximum stress experienced by the soil. The most recently developed fitting method to estimate precompression stress (Gompertz) is based on the assumption of an S-shape stress...

Mindfulness-Based Stress Reduction for Low-Income, Predominantly African American Women with PTSD and a History of Intimate Partner Violence

Science.gov (United States)

Dutton, Mary Ann; Bermudez, Diana; Matas, Armely; Majid, Haseeb; Myers, Neely L.

2013-01-01

In this article, we consider the use of Mindfulness-Based Stress Reduction (MBSR; Kabat-Zinn, 1991) as a community-based intervention for posttraumatic stress disorder (PTSD) among low-income, predominantly African American women with a history of intimate partner violence (IPV). The results of a pilot randomized clinical trial (RCT) of MBSR as an…

Simplified method of calculating residual stress in circumferential welding of piping

International Nuclear Information System (INIS)

Umemoto, Tadahiro

1984-01-01

Many circumferential joints of piping are used in as-welded state, but in these welded joints, the residual stress as high as the yield stress of materials arises, and causes to accelerate stress corrosion cracking and corrosion fatigue. The experiment or the finite element method to clarify welding residual stress requires much time and labor, and is expensive, therefore, the author proposed the simplified method of calculation. The heating and cooling process of welding is very complex, and cannot be modeled as it is, therefore, it was assumed that in multiple layer welding, the welding condition of the last layer determines the residual stress, that material constants are invariable regardless of temperature, that the temperature distribution and residual stress are axisymmetric, and that there is repeated stress-strain relation in the vicinity of welded parts. The temperature distribution at the time of welding, thermal stress and welding residual stress are analyzed, and the material constants used for the calculation of residual stress are given. As the example of calculation, the effect of welding heat input and materials is shown. The extension of the method to a thick-walled pipe is discussed. (Kako, I.)

Method for measuring biaxial stress in a body subjected to stress inducing loads

Science.gov (United States)

Clotfelter, W. N. (Inventor)

1977-01-01

A method is described for measuring stress in test articles including the steps of obtaining for a calibrating specimen a series of transit time differentials between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated through the specimen as it is subjected to known stress load of a series of stress loads for thus establishing a series of indications of the magnitudes for stress loads induced in the specimen, and thereafter obtaining a transit time differential between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated in the planes of the stress axes of a test article and comparing the transit time differential thus obtained to the series of transit time differentials obtained for the specimen to determine the magnitude of biaxial stress in the test article.

METHODS OF REDUCTION OF FREE PHENOL CONTENT IN PHENOLIC FOAM

Directory of Open Access Journals (Sweden)

Bruyako Mikhail Gerasimovich

2012-12-01

method aimed at reduction of toxicity of phenolic foams consists in the introduction of a composite mixture of chelate compounds. Raw materials applied in the production of phenolic foams include polymers FRB-1A and VAG-3. The aforementioned materials are used to produce foams FRP-1. Introduction of 1% aluminum fluoride leads to the 40% reduction of the free phenol content in the foam. Introduction of crystalline zinc chloride accelerates the foaming and curing of phenolic foams. The technology that contemplates the introduction of zeolites into the mixture includes pre-mixing with FRB -1A and subsequent mixing with VAG-3; thereafter, the composition is poured into the form, in which the process of foaming is initiated. The content of free phenol was identified using the method of UV spectroscopy. The objective of the research was to develop methods of reduction of the free phenol content in the phenolic foam.

Relationships between adolescents' test anxiety, stress and sleep

NARCIS (Netherlands)

Dewald, J.F.; Meijer, A.M.; Oort, F.J.; Bögels, S.M.

2012-01-01

Objective. This study aims to investigate the relationship between adolescents' test anxiety, stress and different aspects of sleep. Method. 175 adolescents (70.8% girls, mean age 15.14 years) participated in the study. Test anxiety, stress and chronic sleep reduction were assessed at baseline using

Students and teachers benefit from Mindfulness-Based Stress Reduction in a school-embedded pilot study

Directory of Open Access Journals (Sweden)

Sarah eGouda

2016-04-01

Full Text Available Objective: There is a research gap in studies that evaluate the effectiveness of a school-embedded mindfulness-based intervention for both students and teachers. To address this gap, the present pilot study reviews relevant literature and investigates whether students and teachers who participate in separate Mindfulness-Based Stress Reduction (MBSR courses show improvements across a variety of psychological variables including areas of mental health and creativity. Methods: The study applied a controlled waitlist design with three measurement points. A total of 29 students (n = 15 in the intervention and n = 14 in the waitlist group and 29 teachers (n = 14 in the intervention and n = 15 in the waitlist group completed questionnaires before and after the MBSR course. The intervention group was also assessed after a four-month follow-up period. Results: Relative to the control group, significant improvements in self-reported stress, self-regulation, school-specific self-efficacy and interpersonal problems were found among the students who participated in the MBSR course (p < .05, Cohens` d ranges from 0.62-0.68. Medium effect sizes on mindfulness, anxiety and creativity indicate a realistic potential in those areas. By contrast, teachers in the intervention group showed significantly higher self-reported mindfulness levels and reduced interpersonal problems compared to the control group(p < .05, Cohens` d = 0.66 and 0.42, respectively, with medium effect sizes on anxiety and emotion regulation. Conclusion: The present findings contribute to a growing body of studies investigating mindfulness in schools by discussing the similarities and differences in the effects of MBSR on students and teachers as well as stressing the importance of investigating interpersonal effects.

Mindfulness-based stress reduction for the treatment of irritable bowel syndrome symptoms: a randomized wait-list controlled trial.

Science.gov (United States)

Zernicke, Kristin A; Campbell, Tavis S; Blustein, Philip K; Fung, Tak S; Johnson, Jillian A; Bacon, Simon L; Carlson, Linda E

2013-09-01

Irritable bowel syndrome (IBS) is a functional disorder of the lower gastrointestinal (GI) tract affected by stress, which may benefit from a biopsychosocial treatment approach such as mindfulness-based stress reduction (MBSR). A treatment as usual (TAU) wait-list controlled trial was conducted in Calgary, Canada to investigate the impact of MBSR on IBS symptoms. It was hypothesized that MBSR patients would experience greater reduction in overall IBS symptom severity and self-reported symptoms of stress relative to control patients. Ninety patients diagnosed with IBS using the Rome III criteria were randomized to either an immediate MBSR program (n = 43) or to wait for the next available program (n = 47). Patients completed IBS symptom severity, stress, mood, quality of life (QOL), and spirituality scales pre- and post-intervention or waiting period and at 6-month follow-up. Intent-to-treat linear mixed model analyses for repeated measures were conducted, followed by completers analyses. While both groups exhibited a decrease in IBS symptom severity scores over time, the improvement in the MBSR group was greater than the controls and was clinically meaningful, with symptom severity decreasing from constantly to occasionally present. Pre- to post-intervention dropout rates of 44 and 23 % for the MBSR and control groups, respectively, were observed. At 6-month follow-up, the MBSR group maintained a clinically meaningful improvement in overall IBS symptoms compared to the wait-list group, who also improved marginally, resulting in no statistically significant differences between groups at follow-up. Improvements in overall mood, QOL, and spirituality were observed for both groups over time. The results of this trial provide preliminary evidence for the feasibility and efficacy of a mindfulness intervention for the reduction of IBS symptom severity and symptoms of stress and the maintenance of these improvements at 6 months post-intervention. Attention and self

Measurement of edge residual stresses in glass by the phase-shifting method

Science.gov (United States)

Ajovalasit, A.; Petrucci, G.; Scafidi, M.

2011-05-01

Control and measurement of residual stress in glass is of great importance in the industrial field. Since glass is a birefringent material, the residual stress analysis is based mainly on the photoelastic method. This paper considers two methods of automated analysis of membrane residual stress in glass sheets, based on the phase-shifting concept in monochromatic light. In particular these methods are the automated versions of goniometric compensation methods of Tardy and Sénarmont. The proposed methods can effectively replace manual methods of compensation (goniometric compensation of Tardy and Sénarmont, Babinet and Babinet-Soleil compensators) provided by current standards on the analysis of residual stresses in glasses.

Evaluation methods of vibration stress of small bore piping

Energy Technology Data Exchange (ETDEWEB)

Hiramatsu, Miki; Sasaki, Toru [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Fatigue fracture by vibration stress is one of the main causes of troubles which occur at small bore piping in nuclear power plants. Therefore at the plants they manage small bore piping using a method in which their vibration accelerations are measured and the vibration stresses are calculated. In this work, vibration tests for two sets of mock-ups simulating actual piping in the plants by sinusoidal oscillation and by that obtained at an actual plant were carried out, and then an evaluation method was developed to obtain proper value of vibration stress from the measured data by the vibration tests. In comparison of the vibration stress obtained from the measured acceleration with that directly measured using strain gauges, it is confirmed that accurate vibration stress can be evaluated by a formula in which the real center of gravity of small bore piping and the acceleration of main (system) piping are considered. (author)

Vibration of carbon nanotubes with defects: order reduction methods

Science.gov (United States)

Hudson, Robert B.; Sinha, Alok

2018-03-01

Order reduction methods are widely used to reduce computational effort when calculating the impact of defects on the vibrational properties of nearly periodic structures in engineering applications, such as a gas-turbine bladed disc. However, despite obvious similarities these techniques have not yet been adapted for use in analysing atomic structures with inevitable defects. Two order reduction techniques, modal domain analysis and modified modal domain analysis, are successfully used in this paper to examine the changes in vibrational frequencies, mode shapes and mode localization caused by defects in carbon nanotubes. The defects considered are isotope defects and Stone-Wales defects, though the methods described can be extended to other defects.

Research Progress on Measurement Methods and Influence Factors of Thin-film Stress

Directory of Open Access Journals (Sweden)

MA Yibo

2018-02-01

Full Text Available With the size of thin-film electronic devices decreasing, the film stress became an important reason for the failure of thin film devices. Film stress not only affected the membrane structure, but also associated with film optics, electricity, mechanics and other properties, therefore film stress turned into one hot spot in the research field of thin-film materials. This paper reviewed the latest research progress of film stress, substrate curvature method, X-ray diffraction technique and Raman spectroscopy, several frequently used stress measuring techniques were compared and analyzed, and composition ratios of thin film, substrate types, magnetron sputtering process parameters (sputtering power, work pressure, substrate temperature and annealing etc. factors influencing thin film stress were summarized. It was found that substrate curvature method was suitable for measuring almost all kinds of thin film materials. X-ray diffraction and Raman spectroscopy were just fit for measuring materials with characteristic peaks. Nanoindentation method required extra stress-free samples as comparison experiments. During film fabrication and annealing process, film stress usually transited from compressive to tensile status, and several factors combined together could affect stress, so film stress could be reached the minimum value or even stress-free status through setting appropriate parameters. Finally, combined with film stress research status, accurate stress measurement methods for different materials as a thin-film stress research direction were introduced, and challenges in thin film detection range were pointed out.

Stress-first protocol for myocardial perfusion SPECT imaging with semiconductor cameras: high diagnostic performances with significant reduction in patient radiation doses

International Nuclear Information System (INIS)

Perrin, Mathieu; Claudin, Marine; Veran, Nicolas; Morel, Olivier; Besseau, Cyril; Boutley, Henri; Djaballah, Wassila; Poussier, Sylvain; Verger, Antoine; Moulin, Frederic; Imbert, Laetitia; Karcher, Gilles; Marie, Pierre-Yves

2015-01-01

Effective doses of 14 mSv or higher are currently being attained in patients having stress and rest myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) performed on the same day with conventional protocols. This study aimed to assess the actual reduction in effective doses as well as diagnostic performances for MPI routinely planned with: (1) high-sensitivity cadmium zinc telluride (CZT) cameras, (2) very low injected activities and (3) a stress-first protocol where the normality of stress images may lead to avoiding rest imaging. During a 1-year period, 2,845 patients had MPI on a CZT camera, a single-day stress-first protocol and low injected activities (120 MBq of 99m Tc-sestamibi at stress for 75 kg body weight and threefold higher at rest). The ability to detect > 50 % coronary stenosis was assessed in a subgroup of 149 patients who also had coronary angiography, while the normalcy rate was assessed in a subgroup of 128 patients with a low pretest likelihood of coronary artery disease (<10 %). Overall, 33 % of patients had abnormal MPI of which 34 % were women and 34 % were obese. The mean effective doses and the percentage of exams involving only stress images were: (1) 3.53 ± 2.10 mSv and 37 % in the overall population, (2) 4.83 ± 1.56 mSv and 5 % in the subgroup with angiography and (3) 1.96 ± 1.52 mSv and 71 % in the low-probability subgroup. Sensitivity and global accuracy for identifying the 106 patients with coronary stenosis were 88 and 80 %, respectively, while the normalcy rate was 97 %. When planned with a low-dose stress-first protocol on a CZT camera, MPI provides high diagnostic performances and a dramatic reduction in patient radiation doses. This reduction is even greater in low-risk subgroups with high rates of normal stress images, thus allowing the mean radiation dose to be balanced against cardiac risk in targeted populations. (orig.)

Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

Directory of Open Access Journals (Sweden)

M. Sarai Tabrizi

2016-10-01

Full Text Available Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil response to salinity and to evaluate the effectiveness of available mathematical models for the yield estimation of the Basil . Materials and Methods: The extensive experiments were conducted with 13 natural saline water treatments including 1.2, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.5, 4, 5, 6, 8, and 10 dSm-1. Water salinity treatments were prepared by mixing Shoor River water with fresh water. In order to quantify the salinity effect on Basil yield, seven mathematical models including Maas and Hoffman (1977, van Genuchten and Hoffman (1984, Dirksen and Augustijn (1988, and Homaee et al., (2002 were used. One of the relatively recent methods for soil water content measurements is theta probes instrument. Theta probes instrument consists of four probes with 60 mm long and 3 mm diameter, a water proof container (probe structure, and a cable that links input and output signals to the data logger display. The advantages that have been attributed to this method are high precision and direct and rapid measurements in the field and greenhouse. The range of measurements is not limited like tensiometer and is from saturation to wilting point. In this study, Theta probes instrument was calibrated by weighing method for exact irrigation scheduling. Relative transpiration was calculated using daily soil water content changes. A coarse sand layer with 2 centimeters thick was used to decrease evaporation from the surface soil of the pots. Quantity comparison of the used models was done

Internal Stress Monitoring of In-Service Structural Steel Members with Ultrasonic Method.

Science.gov (United States)

Li, Zuohua; He, Jingbo; Teng, Jun; Wang, Ying

2016-03-23

Internal stress in structural steel members is an important parameter for steel structures in their design, construction, and service stages. However, it is hard to measure via traditional approaches. Among the existing non-destructive testing (NDT) methods, the ultrasonic method has received the most research attention. Longitudinal critically refracted (Lcr) waves, which propagate parallel to the surface of the material within an effective depth, have shown great potential as an effective stress measurement approach. This paper presents a systematic non-destructive evaluation method to determine the internal stress in in-service structural steel members using Lcr waves. Based on theory of acoustoelasticity, a stress evaluation formula is derived. Factor of stress to acoustic time difference is used to describe the relationship between stress and measurable acoustic results. A testing facility is developed and used to demonstrate the performance of the proposed method. Two steel members are measured by using the proposed method and the traditional strain gauge method for verification. Parametric studies are performed on three steel members and the aluminum plate to investigate the factors that influence the testing results. The results show that the proposed method is effective and accurate for determining stress in in-service structural steel members.

Internal Stress Monitoring of In-Service Structural Steel Members with Ultrasonic Method

Science.gov (United States)

Li, Zuohua; He, Jingbo; Teng, Jun; Wang, Ying

2016-01-01

Internal stress in structural steel members is an important parameter for steel structures in their design, construction, and service stages. However, it is hard to measure via traditional approaches. Among the existing non-destructive testing (NDT) methods, the ultrasonic method has received the most research attention. Longitudinal critically refracted (Lcr) waves, which propagate parallel to the surface of the material within an effective depth, have shown great potential as an effective stress measurement approach. This paper presents a systematic non-destructive evaluation method to determine the internal stress in in-service structural steel members using Lcr waves. Based on theory of acoustoelasticity, a stress evaluation formula is derived. Factor of stress to acoustic time difference is used to describe the relationship between stress and measurable acoustic results. A testing facility is developed and used to demonstrate the performance of the proposed method. Two steel members are measured by using the proposed method and the traditional strain gauge method for verification. Parametric studies are performed on three steel members and the aluminum plate to investigate the factors that influence the testing results. The results show that the proposed method is effective and accurate for determining stress in in-service structural steel members. PMID:28773347

Simulation of multivariate stationary stochastic processes using dimension-reduction representation methods

Science.gov (United States)

Liu, Zhangjun; Liu, Zenghui; Peng, Yongbo

2018-03-01

In view of the Fourier-Stieltjes integral formula of multivariate stationary stochastic processes, a unified formulation accommodating spectral representation method (SRM) and proper orthogonal decomposition (POD) is deduced. By introducing random functions as constraints correlating the orthogonal random variables involved in the unified formulation, the dimension-reduction spectral representation method (DR-SRM) and the dimension-reduction proper orthogonal decomposition (DR-POD) are addressed. The proposed schemes are capable of representing the multivariate stationary stochastic process with a few elementary random variables, bypassing the challenges of high-dimensional random variables inherent in the conventional Monte Carlo methods. In order to accelerate the numerical simulation, the technique of Fast Fourier Transform (FFT) is integrated with the proposed schemes. For illustrative purposes, the simulation of horizontal wind velocity field along the deck of a large-span bridge is proceeded using the proposed methods containing 2 and 3 elementary random variables. Numerical simulation reveals the usefulness of the dimension-reduction representation methods.

Calculation of mixed mode stress intensity factors using an alternating method

International Nuclear Information System (INIS)

Sakai, Takayuki

1999-01-01

In this study, mixed mode stress intensity factors (K I and K II ) of a square plate with a notch were calculated using a finite element alternating method. The obtained results were compared with the ones by a finite element method, and it was shown that the finite element alternating method can accurately estimate mixed mode stress intensity factors. Then, using this finite element alternating method, mixed mode stress intensity factors were calculated as changing the size and position of the notch, and its simplified equations were proposed. (author)

Adolescents' sleep in low-stress and high-stress (exam) times: a prospective quasi-experiment.

Science.gov (United States)

Dewald, Julia F; Meijer, Anne Marie; Oort, Frans J; Kerkhof, Gerard A; Bögels, Susan M

2014-01-01

This prospective quasi-experiment (N = 175; mean age = 15.14 years) investigates changes in adolescents' sleep from low-stress (regular school week) to high-stress times (exam week), and examines the (moderating) role of chronic sleep reduction, baseline stress, and gender. Sleep was monitored over three consecutive weeks using actigraphy. Adolescents' sleep was more fragmented during the high-stress time than during the low-stress time, meaning that individuals slept more restless during stressful times. However, sleep efficiency, total sleep time, and sleep onset latency remained stable throughout the three consecutive weeks. High chronic sleep reduction was related to later bedtimes, later sleep start times, later sleep end times, later getting up times, and more time spent in bed. Furthermore, low chronic sleep reduction and high baseline stress levels were related to more fragmented sleep during stressful times. This study shows that stressful times can have negative effects on adolescents' sleep fragmentation, especially for adolescents with low chronic sleep reduction or high baseline stress levels.

Applicability of initial stress measurement methods to Horonobe Siliceous rocks and initial stress state around Horonobe Underground Research Laboratory

International Nuclear Information System (INIS)

Sanada, Hiroyuki; Niunoya, Sumio; Matsui, Hiroya; Fujii, Yoshiaki

2009-01-01

Understanding initial stress condition in deep underground is important for such construction as rock cavern for geological disposal of HLW and underground power plant. Neogene sedimentary rock is widely distributed in Japan. There are only a few studies of initial stress measurement in Neogene sedimentary rock mass in Japan due to difficulty of measurement. Evaluation of initial stress condition around Horonobe Underground Research Laboratory Project was carried out in order to understand initial stress condition and applicability of AE, DSCA and hydraulic fracturing (HF) methods to Neogene sedimentary rock. Initial stress values obtained from AE method is smaller than overburden pressure due to time dependency of Kaizer effect. It would be difficult to use AE method as initial stress measurement method for Horonobe Siliceous rocks. Principal stress values by DSCA are similar to those by HF tests. Directions of maximum horizontal principal stresses are approximately in E-W and corresponded to HF results. In HF, rod type and wire-line type systems were compared. Workability of rod type was much better than wire-line type. However, re-opening pressure were not able to be precisely measured in case of rod type system due to the large compliance of the packers and rods. Horizontal maximum and minimum principal stresses increase linearly in HF results. Deviatoric stress is acting at shallow depth. Initial stress condition approaches hydrostatic condition with depth. Direction of maximum horizontal principal stress was in E-W direction which was similar to tectonic movement around Horonobe URL by triangular surveying. (author)

Stress-tension reduction in the treatment of sexually tortured women--an exploratory study.

Science.gov (United States)

Larsen, H; Pagaduan-Lopez, J

1987-01-01

Three women who had been tortured and sexually abused during imprisonment as political prisoners during the dictatorship in the Philippines were treated with a nonverbal, manual stress-tension reduction therapy (STRT). All women had difficulty in sexual and social relationships and a series of unspecific complaints such as headache, dizziness, irritability, aggressiveness toward their own children, etc. The therapy is described. A series of four sessions was given each woman, followed by group training. A remarkable improvement was noted, and it is suggested that STRT may be use in other sexological disorders.

Evaluation of Stress Loaded Steel Samples Using Selected Electromagnetic Methods

International Nuclear Information System (INIS)

Chady, T.

2004-01-01

In this paper the magnetic leakage flux and eddy current method were used to evaluate changes of materials' properties caused by stress. Seven samples made of ferromagnetic material with different level of applied stress were prepared. First, the leakage magnetic fields were measured by scanning the surface of the specimens with GMR gradiometer. Next, the same samples were evaluated using an eddy current sensor. A comparison between results obtained from both methods was carried out. Finally, selected parameters of the measured signal were calculated and utilized to evaluate level of the applied stress. A strong coincidence between amount of the applied stress and the maximum amplitude of the derivative was confirmed

A finite-dimensional reduction method for slightly supercritical elliptic problems

Directory of Open Access Journals (Sweden)

Riccardo Molle

2004-01-01

Full Text Available We describe a finite-dimensional reduction method to find solutions for a class of slightly supercritical elliptic problems. A suitable truncation argument allows us to work in the usual Sobolev space even in the presence of supercritical nonlinearities: we modify the supercritical term in such a way to have subcritical approximating problems; for these problems, the finite-dimensional reduction can be obtained applying the methods already developed in the subcritical case; finally, we show that, if the truncation is realized at a sufficiently large level, then the solutions of the approximating problems, given by these methods, also solve the supercritical problems when the parameter is small enough.

Effect of a weight reduction program on baseline and stress-induced heart rate variability in children with obesity.

Science.gov (United States)

Mazurak, Nazar; Sauer, Helene; Weimer, Katja; Dammann, Dirk; Zipfel, Stephan; Horing, Björn; Muth, Eric R; Teufel, Martin; Enck, Paul; Mack, Isabelle

2016-02-01

Autonomic dysregulation is a well-established feature in adults with obesity but not in children. Since this dysregulation could contribute to weight dynamics, this study aimed to compare autonomic regulation in children with obesity and normal-weight peers and to track autonomic status during weight reduction. Sixty children with obesity and 27 age- and sex-matched normal-weight healthy participants were included. Heart rate variability (HRV) was assessed at baseline and during a mental stress test and a subsequent recovery period. Children with obesity were investigated both upon admission and discharge. Upon admission, no significant differences in HRV parameters were found for normal-weight participants and those with obesity. Inpatient treatment led to significant changes in HRV with increase in general variability (standard deviation of the normal-to-normal interval (SDNN), P Children with obesity had sympathetic activation similar to normal-weight controls during mental stress with subsequent return to baseline values, and weight loss did not affect this profile. A weight reduction program induced a change in autonomic activity in children with obesity toward parasympathetic dominance but had no influence on autonomic nervous system reactivity during stress conditions. © 2015 The Obesity Society.

Method of dimensionality reduction in contact mechanics and friction

CERN Document Server

Popov, Valentin L

2015-01-01

This book describes for the first time a simulation method for the fast calculation of contact properties and friction between rough surfaces in a complete form. In contrast to existing simulation methods, the method of dimensionality reduction (MDR) is based on the exact mapping of various types of three-dimensional contact problems onto contacts of one-dimensional foundations. Within the confines of MDR, not only are three dimensional systems reduced to one-dimensional, but also the resulting degrees of freedom are independent from another. Therefore, MDR results in an enormous reduction of the development time for the numerical implementation of contact problems as well as the direct computation time and can ultimately assume a similar role in tribology as FEM has in structure mechanics or CFD methods, in hydrodynamics. Furthermore, it substantially simplifies analytical calculation and presents a sort of “pocket book edition” of the entirety contact mechanics. Measurements of the rheology of bodies in...

Measurements of Residual Stresses In Cold-Rolled 304 Stainless Steel Plates Using X-Ray Diffraction with Rietveld Refinement Method

International Nuclear Information System (INIS)

Parikin; Killen, P; Rafterry, A.

2009-01-01

The determination of the residual stresses using X-ray powder diffraction in a series of cold-rolled 304 stainless steel plates, deforming 0, 34, 84, 152, 158, 175 and 196 % reduction in thickness has been carried out. The diffraction data were analyzed using the Rietveld structure refinement method. The analysis shows that for all specimens, the martensite particles are closely in compression and the austenite matrix is in tension. Both the martensite and austenite, for a sample reducing 34% in thickness (containing of about 1% martensite phase) the average lattice strains are anisotropic and decrease approximately exponential with an increase in the corresponding percent reduction (essentially phase content). It is shown that this feature can be qualitatively understood by taking into consideration the thermal expansion mismatch between the martensite and austenite grains. Also, for all cold-rolled stainless steel specimens, the diffraction peaks are broader than the unrolled one (instrumental resolution), indicating that the strains in these specimens are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was predicted. The average residual stresses in cold-rolled 304 stainless steel plates showed a combination effect of hydrostatic stresses of the martensite particles and the austenite matrix. (author)

Nonlinear dimensionality reduction methods for synthetic biology biobricks' visualization.

Science.gov (United States)

Yang, Jiaoyun; Wang, Haipeng; Ding, Huitong; An, Ning; Alterovitz, Gil

2017-01-19

Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps. By extracting biobricks from synthetic biology database Registry of Standard Biological Parts, six combinations of various types of biobricks are tested. The visualization graphs illustrate discriminated biobricks and inappropriately labeled biobricks. Clustering algorithm K-means is adopted to quantify the reduction results. The average clustering accuracy for Isomap and Laplacian Eigenmaps are 0.857 and 0.844, respectively. Besides, Laplacian Eigenmaps is 5 times faster than Isomap, and its visualization graph is more concentrated to discriminate biobricks. By combining normalized edit distance with Isomap and Laplacian Eigenmaps, synthetic biology biobircks are successfully visualized in two dimensional space. Various types of biobricks could be discriminated and inappropriately labeled biobricks could be determined, which could help to assess crowdsourcing-based synthetic biology databases' quality, and make biobricks selection.

The Influence of Exercise Empowerment on Life Stress

Directory of Open Access Journals (Sweden)

Tonya M. Parker

2017-10-01

Full Text Available Background: Psychological stress – when an individual perceives that the environment exceeds their ability to meet the demands placed on them - is common in college students and exercise, and specifically instructional physical activity courses, is frequently cited as a one method of stress reduction. Objective: Determine any relationship between exercise empowerment and perceived life stress for those participating in instructional physical activity courses (IPAC. Methods: All undergraduate students (n = 3388 enrolled in IPAC in 15-week IPAC at a large university were surveyed on perceived life stress (PSS, empowerment in exercise (EES, and specific demographic variables. Results: 944 of 3388 enrolled students (Nov. 2015, April 2016 completed the survey. The data revealed GPA (p < 0.002, sex (p < 0.000, and EES (p < 0.001 showed differences for PSS. It was determined that EES, sex, and GPA predicted PSS differently for students according to their year in college. Conclusions: For freshman and seniors, sex and lower GPA were a stronger predictor of PSS with no mitigating effect of exercise empowerment. For sophomores and juniors the level of life stress was lower at higher levels of exercise empowerment. These findings support a complex relationship between exercise empowerment and life stress. While exercise is cited as a method for stress reduction the relationship between exercise empowerment and life stress for college-aged students is not as straightforward as it may seem.

Measurement of residual stresses by the moire method

Science.gov (United States)

Sciammarella, C. A.; Albertazzi, A., Jr.

Three different applications of the moire method to the determination of residual stresses and strains are presented. The three applications take advantage of the property of ratings to record the changes of the surface they are printed on. One of the applications deals with thermal residual stresses, another with contact residual stress and the third one is a generalization of the blind hole technique. This last application is based on a computer assisted moire technique and on the generalization of the quasi-heterodyne techniques of fringe pattern analysis.

Reduced order methods for modeling and computational reduction

CERN Document Server

Rozza, Gianluigi

2014-01-01

This monograph addresses the state of the art of reduced order methods for modeling and computational reduction of complex parametrized systems, governed by ordinary and/or partial differential equations, with a special emphasis on real time computing techniques and applications in computational mechanics, bioengineering and computer graphics.  Several topics are covered, including: design, optimization, and control theory in real-time with applications in engineering; data assimilation, geometry registration, and parameter estimation with special attention to real-time computing in biomedical engineering and computational physics; real-time visualization of physics-based simulations in computer science; the treatment of high-dimensional problems in state space, physical space, or parameter space; the interactions between different model reduction and dimensionality reduction approaches; the development of general error estimation frameworks which take into account both model and discretization effects. This...

Combating stress risks with the job stress self diagnostic method: paper XV World Congress of Sociology 2002

OpenAIRE

Oeij, P.R.A.

2002-01-01

In this paper of the World Congress of Sociology 2002 of ISA (International Sociological Association), the content and uses of the Job Stress Self Diagnostic Method (JSSDM) are described. The JSSDM aim is (a) to diagnose work processes to determine the presence of conditions for control problems and stress risks, and (b) to develop solutions to combat stress risks on organisational level. The method is based on three theories of job and organisation design and on the insight to combine viewpo...

Measurement of residual stress in quenched 1045 steel by the nanoindentation method

International Nuclear Information System (INIS)

Zhu Lina; Xu Binshi; Wang Haidou; Wang Chengbiao

2010-01-01

In this paper, the residual stress in quenched AISI 1045 steel was measured by a recently developed nanoindentation technique. Depth control mode was adopted to measure the residual stress. It was found that residual compressive stress was generated in the quenched steel. The material around nanoindents exhibits significant pile-up deformation. A new method was proposed to determine the real contact area for pile-up material on the basis of invariant pile-up morphology of the loaded or unloaded states. The results obtained by the new method were in good agreement with the residual stresses measured by the classical X-ray diffraction (XRD) method. - Research Highlights: → A new method was proposed to measure the real contact area for pile-up materials. → The real contact depth is defined as the sum of h max and the pile-up height h p . → The value of residual stress measured by the nanoindentation method was in good agreement with that by the XRD method.

Assessment on the methods of measuring the tyre-road contact patch stresses

Science.gov (United States)

Anghelache, G.; Moisescu, A.-R.; Buretea, D.

2017-08-01

The paper reviews established and modern methods for investigating tri-axial stress distributions in the tyre-road contact patch. The authors used three methods of measuring stress distributions: strain gauge method; force sensing technique; acceleration measurements. Four prototypes of instrumented pins transducers involving mentioned measuring methods were developed. Data acquisitions of the contact patch stresses distributions were performed using each transducer with instrumented pin. The results are analysed and compared, underlining the advantages and drawbacks of each method. The experimental results indicate that the three methods are valuable.

A study on the stress history condensation method for a fatigue monitoring system

International Nuclear Information System (INIS)

Ko, Hanok; Jhung, Myungjo; Lee, Kihyoung

2014-01-01

Fatigue damage is the one of important aging mechanisms. Time-varying thermal, pressure and mechanical loads produce perturbations of stress cycles primarily at the surface of a component. Stress cycles of sufficient magnitude cause fatigue damage, which can ultimately lead to cracking of the component. According to NUREG-1801, fatigue monitoring systems identify acceptable aging management programs, including programs for fatigue and cyclic operation. In a monitoring system, the rainflow counting method is mainly used as the stress cycle counting method. Before determining the stress cycles using rainflow counting method, stress extremum (or peak/valley) must be identified. Because real stress history contains large numbers of very small cycles, which may be a result of digitization noise, these cycles will slow down the analysis and distort the scaling of graphical displays. As a result, it is found that stress cycles smaller than a threshold value are discarded by using the proposed method. In this paper, an engineering methodology which extracts extremum from the real-time transient data, so-called SEE, has been developed. The proposed method is very simple and so fast because it only uses the difference between the input value and local peak/valley. The stress cycles counted by two methods are compared with those counted by only rainflow counting method and it is found that stress cycles smaller than a threshold value were eliminated

Effects of Lifestyle Modification on Telomerase Gene Expression in Hypertensive Patients: A Pilot Trial of Stress Reduction and Health Education Programs in African Americans.

Directory of Open Access Journals (Sweden)

Shanthi Duraimani

Full Text Available African Americans suffer from disproportionately high rates of hypertension and cardiovascular disease. Psychosocial stress, lifestyle and telomere dysfunction contribute to the pathogenesis of hypertension and cardiovascular disease. This study evaluated effects of stress reduction and lifestyle modification on blood pressure, telomerase gene expression and lifestyle factors in African Americans.Forty-eight African American men and women with stage I hypertension who participated in a larger randomized controlled trial volunteered for this substudy. These subjects participated in either stress reduction with the Transcendental Meditation technique and a basic health education course (SR or an extensive health education program (EHE for 16 weeks. Primary outcomes were telomerase gene expression (hTERT and hTR and clinic blood pressure. Secondary outcomes included lifestyle-related factors. Data were analyzed for within-group and between-group changes.Both groups showed increases in the two measures of telomerase gene expression, hTR mRNA levels (SR: p< 0.001; EHE: p< 0.001 and hTERT mRNA levels (SR: p = 0.055; EHE: p< 0.002. However, no statistically significant between-group changes were observed. Both groups showed reductions in systolic BP. Adjusted changes were SR = -5.7 mm Hg, p< 0.01; EHE = -9.0 mm Hg, p < 0.001 with no statistically significant difference between group difference. There was a significant reduction in diastolic BP in the EHE group (-5.3 mm Hg, p< 0.001 but not in SR (-1.2 mm Hg, p = 0.42; the between-group difference was significant (p = 0.04. The EHE group showed a greater number of changes in lifestyle behaviors.In this pilot trial, both stress reduction (Transcendental Meditation technique plus health education and extensive health education groups demonstrated increased telomerase gene expression and reduced BP. The association between increased telomerase gene expression and reduced BP observed in this high

Simplified calculation of thermal stresses - on the reduction of effort in the stress analysis of reactor components

International Nuclear Information System (INIS)

Karow, K.

1984-01-01

The fatigue behaviour of reactor components is predominantly determined from the in-service thermal stresses. The calculation of such stresses for a number of temperature transients in the adjacent fluid may be expensive, particularly with complicated structures. Under certain conditions this expense can be reduced considerably with the aid of a rule, which permits interpolation of thermal stresses from known reference values instead of calculation. This paper presents the derivation and method of application of this interpolation rule. The derivation procedure is based on well-known proportionalities between thermal stress range Δsigma in the structure and temperature change ΔT and rate of change T of the fluid in the extreme cases of an ideal thermal shock and quasi-steady-state conditions, respectively. For the real transients in between the relationship Δsigma proportional (ΔT)sup(x) Tsup(1-x)αsup(y) is proposed, where x is the shock-degree and lies between 0 and 1, and, additionally, y designates the influence of the heat transfer coefficient α. This formula yields the interpolation rule. The rule permits interpolation of stress ranges for additional thermal transients from at least 3 reference stresses via x and y. The procedure is applicable to any metallic structure, reduces fatigue analysis effort considerably and yields excellent results. The paper is split up into 2 parts. In the following the derivation of the rule is presented. The second part describes its application and will be published shortly. (orig.)

Reduction of initial stress stiffening by topology optimization

DEFF Research Database (Denmark)

Philippine, M. A.; Sigmund, Ole; Rebeiz, G. M.

2012-01-01

Topology optimization is a rigorous method of obtaining non-intuitive designs. We use it to obtain a capacitive RF switch that stiffens little in response to an increase of the in-plane biaxial stresses that typically develop during MEMS fabrication. The actuation voltage is closely related...... level. We include a volume constraint and a compliance constraint. Topology optimized designs are compared to an intuitively-designed RF switch. The switches contain similar features. The compliance constraint is varied such that the topology optimized switch performance approaches the intuitively......-designed one. Finally, the importance of the compliance constraint and of the robust formulation are discussed....

Stress Coping Techniques For Female Doctors Encountering Sexual ...

African Journals Online (AJOL)

... Muslim and Christian female doctors encounter with sexual harassment. It was also found that sexual harassment cut across all age groups. The findings of these study indicated that stress coping techniques is an effective method in the reduction of stress posed by sexual harassment on female doctors from their patients.

Mindfulness-based stress reduction for parents of young children with developmental delays: implications for parental mental health and child behavior problems.

Science.gov (United States)

Neece, Cameron L

2014-03-01

Parents of children with developmental delays (DD) typically report elevated levels of parental stress compared with parents of typically developing children. Children with DD are also at high risk for exhibiting significant behaviour problems. Parental stress has been shown to impact the development of these behaviour problems; however, it is rarely addressed in interventions aimed at reducing child behaviour problems. The current study examined the efficacy of mindfulness-based stress reduction (MBSR) for parents of children with DD by investigating whether this intervention is effective in reducing parenting stress and whether decreases in parenting stress lead to reductions in behaviour problems among children with DD. Forty six parents of children with DD were randomly assigned to an immediate treatment or wait list-control group. Participants completed questionnaires assessing parental stress and child behaviour problems at intake and at a second assessment, which took place after only the immediate treatment group had received the MBSR. Parents who participated in MBSR reported significantly less stress and depression as well as greater life satisfaction compared with wait list-control parents. Regarding child outcomes, children whose parents participated in MBSR were reported to have fewer behaviour problems following the intervention, specifically in the areas of attention problems and ADHD symptomatology. Results indicated that MBSR may be an effective intervention for ameliorating parental stress and mental health problems among parents of children with DD. Additionally, these benefits may 'spill over' and improve behaviour challenges among these children. © 2013 John Wiley & Sons Ltd.

Comparison of Measured Residual Stress in an Extra Thick Multi-pass Weld Using Neutron Diffraction Method and Inherent Strain Method

International Nuclear Information System (INIS)

Park, JeongUng; An, GyuBaek; Woo, Wan Chuck

2015-01-01

With the increase of large-scale containership, a large amount of high-strength steels with extra thick plates is being extensively used. The welding stress existing in the extra thick welded plates has a significant effect on the integrity of the component in terms of brittle fracture and fatigue behavior. It has been reported that welding residual stress distribution in an extra thick plate can affect the propagation path of the crack. Therefore, it is important to measure the distribution of welding residual stresses for the reliable design of the welded structures. So far various researches have been carried out for the determination of residual stresses on the surface of steels. In this paper, the total residual stresses in the 70 mm thick multipass FACW butt joint were measured by integrating initial stress into ISM. Concretely, two methods named as initial stress integrated ISM and initial inherent strain integrated ISM were employed to determine the total residual stresses. Furthermore, the distributions of residual stresses were compared with the results of the Neutron Diffraction Method(NDM). In order to measure the three dimensional residual stresses in the welded joint with initial stresses existing before welding, initial stress integrated ISM and initial inherent strain integrated ISM were developed. The residual stresses in 70 mm-thick butt joint by flux cored arc welding were carried out with a good accuracy using the two developed methods. The residual stresses in welded joint using both initial stress integrated ISM and initial inherent strain integrated ISM agreed well with the results measured by Neutron Diffraction Method. This suggests that the integrated ISM is a reliable method for residual stress measurement if initial stress existed

Statistical analysis of x-ray stress measurement by centroid method

International Nuclear Information System (INIS)

Kurita, Masanori; Amano, Jun; Sakamoto, Isao

1982-01-01

The X-ray technique allows a nondestructive and rapid measurement of residual stresses in metallic materials. The centroid method has an advantage over other X-ray methods in that it can determine the angular position of a diffraction line, from which the stress is calculated, even with an asymmetrical line profile. An equation for the standard deviation of the angular position of a diffraction line, σsub(p), caused by statistical fluctuation was derived, which is a fundamental source of scatter in X-ray stress measurements. This equation shows that an increase of X-ray counts by a factor of k results in a decrease of σsub(p) by a factor of 1/√k. It also shows that σsub(p) increases rapidly as the angular range used in calculating the centroid increases. It is therefore important to calculate the centroid using the narrow angular range between the two ends of the diffraction line where it starts to deviate from the straight background line. By using quenched structural steels JIS S35C and S45C, the residual stresses and their standard deviations were calculated by the centroid, parabola, Gaussian curve, and half-width methods, and the results were compared. The centroid of a diffraction line was affected greatly by the background line used. The standard deviation of the stress measured by the centroid method was found to be the largest among the four methods. (author)

Standard test method for calibration of surface/stress measuring devices

CERN Document Server

American Society for Testing and Materials. Philadelphia

1997-01-01

Return to Contents page 1.1 This test method covers calibration or verification of calibration, or both, of surface-stress measuring devices used to measure stress in annealed and heat-strengthened or tempered glass using polariscopic or refractometry based principles. 1.2 This test method is nondestructive. 1.3 This test method uses transmitted light, and therefore, is applicable to light-transmitting glasses. 1.4 This test method is not applicable to chemically tempered glass. 1.5 Using the procedure described, surface stresses can be measured only on the “tin” side of float glass. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Wind-Induced Fatigue Analysis of High-Rise Steel Structures Using Equivalent Structural Stress Method

Directory of Open Access Journals (Sweden)

Zhao Fang

2017-01-01

Full Text Available Welded beam-to-column connections of high-rise steel structures are susceptive to fatigue damage under wind loading. However, most fatigue assessments in the field of civil engineering are mainly based on nominal stress or hot spot stress theories, which has the disadvantage of dependence on the meshing styles and massive curves selected. To address this problem, in this paper, the equivalent structural stress method with advantages of mesh-insensitive quality and capability of unifying different stress-life curves (S-N curves into one is introduced to the wind-induced fatigue assessment of a large-scale complicated high-rise steel structure. The multi-scale finite element model is established and the corresponding wind loading is simulated. Fatigue life assessments using equivalent structural stress method, hot spot stress method and nominal stress method are performed, and the results are verified and comparisons are made. The mesh-insensitive quality is also verified. The results show that the lateral weld toe of the butt weld connecting the beam flange plate and the column is the location where fatigue damage most likely happens. Nominal stress method considers fatigue assessment of welds in a more global way by averaging all the stress on the weld section while in equivalent structural stress method and hot spot method local stress concentration can be taken into account more precisely.

Mindfulness-based stress reduction teachers, practice characteristics, cancer incidence, and health: a nationwide ecological description.

Science.gov (United States)

Robb, Sara Wagner; Benson, Kelsey; Middleton, Lauren; Meyers, Christine; Hébert, James R

2015-02-14

Studies have demonstrated the potential of the Mindfulness-Based Stress Reduction (MBSR) program to improve the condition of individuals with health outcomes such as hypertension, diabetes, and chronic pain; improve psychological well-being; reduce stress levels; and increase survival among cancer patients. To date, only one study has focused on the effect of long-term meditation on stress, showing a positive protective relationship. However, the relationship between meditation and cancer incidence remains unexplored. The objective of this study was to describe the state-level relationship between MBSR instructors and their practices and county-level health outcomes, including cancer incidence, in the United States. This ecologic study was performed using geospatial mapping and descriptive epidemiology of statewide MBSR characteristics and overall health, mental health state rankings, and age-adjusted cancer incidence rates. Weak to moderate state-level correlations between meditation characteristics and colorectal and cervical cancer incidence were detected, with states with more meditation (e.g., more MBSR teachers per population) correlated with a decreased cancer incidence. A negative correlation was detected between lung & bronchus cancer and years teaching MBSR only. Moderate positive correlations were detected between Hodgkin's Lymphoma and female breast cancer in relation to all meditation characteristics. Statistically significant correlations with moderate coefficients were detected for overall health ranks and all meditation characteristics, most strongly for total number of years teaching MBSR and total number of years of general meditation practice. Our analyses might suggest that a relationship exists between the total number of MBSR teachers per state and the total number of years of general meditation practice per state, and colorectal and cervical cancer incidence. Positive correlations were observed with overall health rankings. Despite this study

Levels of reduction in van Manen's phenomenological hermeneutic method: an empirical example.

Science.gov (United States)

Heinonen, Kristiina

2015-05-01

To describe reduction as a method using van Manen's phenomenological hermeneutic research approach. Reduction involves several levels that can be distinguished for their methodological usefulness. Researchers can use reduction in different ways and dimensions for their methodological needs. A study of Finnish multiple-birth families in which open interviews (n=38) were conducted with public health nurses, family care workers and parents of twins. A systematic literature and knowledge review showed there were no articles on multiple-birth families that used van Manen's method. Discussion The phenomena of the 'lifeworlds' of multiple-birth families consist of three core essential themes as told by parents: 'a state of constant vigilance', 'ensuring that they can continue to cope' and 'opportunities to share with other people'. Reduction provides the opportunity to carry out in-depth phenomenological hermeneutic research and understand people's lives. It helps to keep research stages separate but also enables a consolidated view. Social care and healthcare professionals have to hear parents' voices better to comprehensively understand their situation; they need further tools and training to be able to empower parents of twins. This paper adds an empirical example to the discussion of phenomenology, hermeneutic study and reduction as a method. It opens up reduction for researchers to exploit.

Effect of mindfulness-based stress reduction on somatic symptoms, distress, mindfulness and spiritual wellbeing in women with breast cancer

DEFF Research Database (Denmark)

Würtzen, Hanne; Dalton, Susanne Oksbjerg; Christensen, Jane

2015-01-01

Background. Women with breast cancer experience different symptoms related to surgical or adjuvant therapy. Previous findings and theoretical models of mind-body interactions suggest that psychological wellbeing, i.e. levels of distress, influence the subjective evaluation of symptoms, which...... influences or determines functioning. The eight-week mindfulness-based stress reduction (MBSR) program significantly reduced anxiety and depression in breast cancer patients in a randomized controlled trial (NCT00990977). In this study we tested the effect of MBSR on the burden of breast cancer related...... somatic symptoms, distress, mindfulness and spiritual wellbeing and evaluated possible effect modification by adjuvant therapy and baseline levels of, distress, mindfulness and spiritual wellbeing. Material and methods. A population-based sample of 336 women Danish women operated for breast cancer stages...

Scintigraphic method for evaluating reductions in local blood volumes in human extremities

DEFF Research Database (Denmark)

Blønd, L; Madsen, Jan Lysgård

2000-01-01

in the experiment. Evaluation of one versus two scintigraphic projections, trials for assessment of the reproducibility, a comparison of the scintigraphic method with a water-plethysmographic method and registration of the fractional reduction in blood volume caused by exsanguination as a result of simple elevation......% in the lower limb experiment and 6% in the upper limb experiment. We found a significant relation (r = 0.42, p = 0.018) between the results obtained by the scintigraphic method and the plethysmographic method. In fractions, a mean reduction in blood volume of 0.49+0.14 (2 SD) was found after 1 min of elevation......We introduce a new method for evaluating reductions in local blood volumes in extremities, based on the combined use of autologue injection of 99mTc-radiolabelled erythrocytes and clamping of the limb blood flow by the use of a tourniquet. Twenty-two healthy male volunteers participated...

Stress description model by non destructive magnetic methods

International Nuclear Information System (INIS)

Flambard, C.; Grossiord, J.L.; Tourrenc, P.

1983-01-01

Since a few years, CETIM investigates analysis possibilities of materials, by developing a method founded on observation of ferromagnetic noise. By experiments, correlations have become obvious between state of the material and recorded signal. These correlations open to industrial applications to measure stresses and strains in elastic and plastic ranges. This article starts with a brief historical account and theoretical backgrounds of the method. The experimental frame of this research is described, and the main results are analyzed. Theoretically, a model was built up, and we present it. It seems in agreement with some experimental observations. The main results concerning stress application, thermal and surface treatments (decarbonizing) are presented [fr

Metal artifact reduction method using metal streaks image subtraction

International Nuclear Information System (INIS)

Pua, Rizza D.; Cho, Seung Ryong

2014-01-01

Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR

A qualitative study on mindfulness-based stress reduction for breast cancer patients: how women experience participating with fellow patients

NARCIS (Netherlands)

Schellekens, Melanie P. J.; Jansen, Ellen T. M.; Willemse, Heidi H. M. A.; van Laarhoven, Hanneke W. M.; Prins, Judith B.; Speckens, Anne E. M.

2016-01-01

Peer support groups for cancer patients show mixed findings regarding effectiveness on psychological wellbeing. When embedded in a psychosocial intervention, such as mindfulness-based stress reduction (MBSR), peer support might be of more benefit to participants. This study is a qualitative

A systematic way for the cost reduction of density fitting methods

International Nuclear Information System (INIS)

Kállay, Mihály

2014-01-01

We present a simple approach for the reduction of the size of auxiliary basis sets used in methods exploiting the density fitting (resolution of identity) approximation for electron repulsion integrals. Starting out of the singular value decomposition of three-center two-electron integrals, new auxiliary functions are constructed as linear combinations of the original fitting functions. The new functions, which we term natural auxiliary functions (NAFs), are analogous to the natural orbitals widely used for the cost reduction of correlation methods. The use of the NAF basis enables the systematic truncation of the fitting basis, and thereby potentially the reduction of the computational expenses of the methods, though the scaling with the system size is not altered. The performance of the new approach has been tested for several quantum chemical methods. It is demonstrated that the most pronounced gain in computational efficiency can be expected for iterative models which scale quadratically with the size of the fitting basis set, such as the direct random phase approximation. The approach also has the promise of accelerating local correlation methods, for which the processing of three-center Coulomb integrals is a bottleneck

Study of reduction methods for irradiation on oral mucositis. The examination of reduction methods for mucosal failure

International Nuclear Information System (INIS)

Tonogi, Morio; Yamane, Genyuki; Aoyagi, Yutaka; Hasegawa, Azusa; Mizoe, Junetsu; Tsujii, Hirohiko

2004-01-01

Reduction methods for irradiation on oral mucosa examined concerning in acute phase of the carbon ion radiotherapy for head and neck malignancies. We enforced a mechanical teeth and gingival cleaning as an Oral hearth care and gargled a polaprezinc with sodium alginate, and azulene- lidocaine with glycerin sodium as a oral linces before radiation. The response of the mucosal failure was reduced compare with no care group. In this Result, we considered that oral hearth care for prevention of infection, and mucosa protection by the drug was important factor. (author)

A numerical analysis method on thermal and shrinkage stress of concrete

International Nuclear Information System (INIS)

Takiguchi, Katsuki; Hotta, Hisato

1991-01-01

Thermal stress often causes cracks in large scale concrete such as that for dam construction. The drying shrinkage of concrete causes cracks in concrete structures. These thermal stress and drying shrinkage stress may be the main reasons cracks occur in concrete, however there is few research which dealt with both stresses together. The problems on the thermal stress and the drying shrinkage are not independent, and should be dealt with together, because both temperature and water content of concrete affect hydration reaction, and the degree of hydration determines all the characteristics of concrete at early age. In this study, the degree of hydration is formulated experimentally, and a numerical stress analysis method taking the hydration reaction in consideration is presented. The formulation of the rate of hydration reaction, the method of analyzing thermal and drying shrinkage stresses, the analytical results for a concrete column and the influence that continuous load exerted to the tensile strength of concrete are reported. The relatively high stress nearly equal to the tensile strength of concrete arises near the surface. (K.I.)

Method for simulating dose reduction in digital mammography using the Anscombe transformation

OpenAIRE

Borges, Lucas R.; de Oliveira, Helder C. R.; Nunes, Polyana F.; Bakic, Predrag R.; Maidment, Andrew D. A.; Vieira, Marcelo A. C.

2016-01-01

Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the d...

Damage approach: A new method for topology optimization with local stress constraints

DEFF Research Database (Denmark)

Verbart, Alexander; Langelaar, Matthijs; van Keulen, Fred

2016-01-01

In this paper, we propose a new method for topology optimization with local stress constraints. In this method, material in which a stress constraint is violated is considered as damaged. Since damaged material will contribute less to the overall performance of the structure, the optimizer...... will promote a design with a minimal amount of damaged material. We tested the method on several benchmark problems, and the results show that the method is a viable alternative for conventional stress-based approaches based on constraint relaxation followed by constraint aggregation....

Repeated swim stress alters brain benzodiazepine receptors measured in vivo

International Nuclear Information System (INIS)

Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.

1989-01-01

The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of [ 3 H]Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in [14C]iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress [an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures], although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results

Repeated swim stress alters brain benzodiazepine receptors measured in vivo

Energy Technology Data Exchange (ETDEWEB)

Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.

1989-06-01

The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of (/sup 3/H)Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in (14C)iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress (an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures), although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results.

Measuring multiple residual-stress components using the contour method and multiple cuts

Energy Technology Data Exchange (ETDEWEB)

Prime, Michael B [Los Alamos National Laboratory; Swenson, Hunter [Los Alamos National Laboratory; Pagliaro, Pierluigi [U. PALERMO; Zuccarello, Bernardo [U. PALERMO

2009-01-01

The conventional contour method determines one component of stress over the cross section of a part. The part is cut into two, the contour of the exposed surface is measured, and Bueckner's superposition principle is analytically applied to calculate stresses. In this paper, the contour method is extended to the measurement of multiple stress components by making multiple cuts with subsequent applications of superposition. The theory and limitations are described. The theory is experimentally tested on a 316L stainless steel disk with residual stresses induced by plastically indenting the central portion of the disk. The stress results are validated against independent measurements using neutron diffraction. The theory has implications beyond just multiple cuts. The contour method measurements and calculations for the first cut reveal how the residual stresses have changed throughout the part. Subsequent measurements of partially relaxed stresses by other techniques, such as laboratory x-rays, hole drilling, or neutron or synchrotron diffraction, can be superimposed back to the original state of the body.

NDE of stresses in thick-walled components by ultrasonic methods

International Nuclear Information System (INIS)

Goebbels, K.; Pitsch, H.; Schneider, E.; Nowack, H.

1985-01-01

The possibilty of measuring stresses - especially residual stresses - by ultrasonic methods has been presented at the 4th and 5th International Conference on NDE in Nuclear Industry. This contribution now presents results of several applications to thick walled components such as turbines and generators for power plants. The measurement technique using linearly polarized shear waves allows one to characterize the homogeneitry of the residual stress situation along and around cylindrically shaped components. Some important results show that the stress distribution integrated over the cross section of the component has not followed in any case the simple relations derived by stress analysts. Conclusions referring to the stress situation inside the components are discussed

A test case of the deformation rate analysis (DRA) stress measurement method

Energy Technology Data Exchange (ETDEWEB)

Dight, P.; Hsieh, A. [Australian Centre for Geomechanics, Univ. of WA, Crawley (Australia); Johansson, E. [Saanio and Riekkola Oy, Helsinki (Finland); Hudson, J.A. [Rock Engineering Consultants (United Kingdom); Kemppainen, K.

2012-01-15

As part of Posiva's site and ONKALO investigations, the in situ rock stress has been measured by a variety of techniques, including hydraulic fracturing, overcoring, and convergence measurements. All these techniques involve direct measurements in a drillhole or at the rock surface. An alternative method is to test drillhole core in a way that enables estimation of the magnitudes and orientations of the in situ rock stress. The Kaiser Effect (KE) and Deformation Rate Analysis (DRA) are two ways to do this. In the work reported here, a 'blind' DRA test was conducted on core obtained from the POSE (Posiva's Olkiluoto Spalling Experiment) niche in the ONKALO. The term 'blind' means that the two first authors of this report, who conducted the tests at the Australian Centre for Geomechanics, did not know the depths below surface at which the cores had been obtained. The results of this DRA Test Case are presented, together with an explanation of the DRA procedure. Also, additional information that would help in such DRA testing and associated analysis is explained. One of the problems in comparing the DRA results with the known Olkiluoto stress field is that the latter is highly variable across the site, as experienced by the previous in situ stress measurements and as predicted by numerical analysis. The variability is mainly caused by the presence of the large brittle deformation zones which perturb the local stress state. However, this variability reduces with depth and the stress field becomes more stable at the {approx} 350 m at which the drillhole cores were obtained. Another compounding difficulty is that the stress quantity, being a second order tensor, requires six independent components for its specification. In other words, comparison of the DRA results and the known stress field requires comparison of six different quantities. In terms of the major principal stress orientation, the DRA results predict an orientation completely

A test case of the deformation rate analysis (DRA) stress measurement method

International Nuclear Information System (INIS)

Dight, P.; Hsieh, A.; Johansson, E.; Hudson, J.A.; Kemppainen, K.

2012-01-01

As part of Posiva's site and ONKALO investigations, the in situ rock stress has been measured by a variety of techniques, including hydraulic fracturing, overcoring, and convergence measurements. All these techniques involve direct measurements in a drillhole or at the rock surface. An alternative method is to test drillhole core in a way that enables estimation of the magnitudes and orientations of the in situ rock stress. The Kaiser Effect (KE) and Deformation Rate Analysis (DRA) are two ways to do this. In the work reported here, a 'blind' DRA test was conducted on core obtained from the POSE (Posiva's Olkiluoto Spalling Experiment) niche in the ONKALO. The term 'blind' means that the two first authors of this report, who conducted the tests at the Australian Centre for Geomechanics, did not know the depths below surface at which the cores had been obtained. The results of this DRA Test Case are presented, together with an explanation of the DRA procedure. Also, additional information that would help in such DRA testing and associated analysis is explained. One of the problems in comparing the DRA results with the known Olkiluoto stress field is that the latter is highly variable across the site, as experienced by the previous in situ stress measurements and as predicted by numerical analysis. The variability is mainly caused by the presence of the large brittle deformation zones which perturb the local stress state. However, this variability reduces with depth and the stress field becomes more stable at the ∼ 350 m at which the drillhole cores were obtained. Another compounding difficulty is that the stress quantity, being a second order tensor, requires six independent components for its specification. In other words, comparison of the DRA results and the known stress field requires comparison of six different quantities. In terms of the major principal stress orientation, the DRA results predict an orientation completely different to the NW-SE regional

Interventions: Employees’ Perceptions of What Reduces Stress

Directory of Open Access Journals (Sweden)

Silvia Pignata

2017-01-01

Full Text Available Objective. To build upon research evaluating stress interventions, this qualitative study tests the framework of the extended Job Demands-Resources model to investigate employees’ perceptions of the stress-reduction measures implemented at 13 Australian universities. Methods. In a cross-sectional survey design, tenured and contract staff indicated whether their overall level of stress had changed during the previous three-four years, and, if so, they described the major causes. A total of 462 staff reported that their level of stress had decreased; the study examines commentary from 115 academic and 304 nonacademic staff who provided details of what they perceived to be effective in reducing stress. Results. Thematic analyses show that the key perceived causes were changes in job or work role, new heads of departments or supervisors, and the use of organizational strategies to reduce or manage stress. A higher percentage of academic staff reported reduced stress due to using protective coping strategies or their increased recognition and/or success, whereas a higher percentage of nonacademic staff reported reduced stress due to increases in staffing resources and/or systems. Conclusion. These results identify the importance of implementing multilevel strategies to enhance employees’ well-being. Nonacademic staff, in particular, specified a variety of organizational stress-reduction interventions.

Noise-based tube current reduction method with iterative reconstruction for reduction of radiation exposure in coronary CT angiography

International Nuclear Information System (INIS)

Shen, Junlin; Du, Xiangying; Guo, Daode; Cao, Lizhen; Gao, Yan; Bai, Mei; Li, Pengyu; Liu, Jiabin; Li, Kuncheng

2013-01-01

Purpose: To investigate the potential of noise-based tube current reduction method with iterative reconstruction to reduce radiation exposure while achieving consistent image quality in coronary CT angiography (CCTA). Materials and methods: 294 patients underwent CCTA on a 64-detector row CT equipped with iterative reconstruction. 102 patients with fixed tube current were assigned to Group 1, which was used to establish noise-based tube current modulation formulas, where tube current was modulated by the noise of test bolus image. 192 patients with noise-based tube current were randomly assigned to Group 2 and Group 3. Filtered back projection was applied for Group 2 and iterative reconstruction for Group 3. Qualitative image quality was assessed with a 5 point score. Image noise, signal intensity, volume CT dose index, and dose-length product were measured. Results: The noise-based tube current modulation formulas were established through regression analysis using image noise measurements in Group 1. Image noise was precisely maintained at the target value of 35.00 HU with small interquartile ranges for Group 2 (34.17–35.08 HU) and Group 3 (34.34–35.03 HU), while it was from 28.41 to 36.49 HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 14% and 41% reduction in effective dose for Group 2 and Group 3 were observed compared with Group 1. Conclusion: Adequate image quality could be maintained at a desired and consistent noise level with overall 14% dose reduction using noise-based tube current reduction method. The use of iterative reconstruction further achieved approximately 40% reduction in effective dose

Review of noise reduction methods for centrifugal fans

Science.gov (United States)

Neise, W.

1981-11-01

Several methods for the reduction of centrifugal fan noise are presented, the most of which are aimed at a lower blade passage frequency level. The methods are grouped into five categories: casing modifications to increase the distance between impeller and cutoff, the introduction of a phase shift of the source pressure fluctuations, impeller modifications, radial clearance between impeller eye and inlet nozzle, and acoustical measures. Resonators mounted at the cutoff of centrifugal fans appear to be a highly efficient and simple means of reducing the blade passage tone, and the method can be used for new fan construction and existing installations without affecting the aerodynamic performance of the fan.

[Study on reductive surgery for pelvic organ prolapse concomitant with anti-incontinence sling for treatment of occult stress urinary incontinence].

Science.gov (United States)

Zhang, Xiaolong; Lu, Yongxian; Shen, Wenjie; Liu, Jingxia; Ge, Jing; Liu, Xin; Zhao, Ying; Niu, Ke; Zhang, Yinghui; Wang, Wenying; Qiu, Chengli

2014-06-01

To evaluate the clinical outcome of anti-incontinence sling in the treatment of occult stress urinary incontinence (OSUI) during reductive surgery for advanced pelvic organ prolapse (POP). From Jun. 2003 to Dec. 2012, 78 patients with OSUI underwent reductive surgery for advanced POP such as high uterosacral ligament suspension, sacrospinous ligament suspension and sacral colpopexy in the First Affiliated Hospital, General Hospital of People's Liberation Army. Among them, 41 patients received reductive surgery alone was enrolled in non-concomitant anti-incontinence group and the other 37 patients who underwent same surgery with tension-free vaginal tape (TVT) or tension-free vaginal tape-obturator technique (TVT-O) was in anti-incontinence group. The patient's demography, objective and subjective outcomes, as well as complications and injures were compared between the two groups. The pelvic organ prolapse quantitation (POP-Q) was used to evaluate the objective outcomes of POP. Urinary distress inventory (UDI-6) and incontinence impact questionnaire short form (IIQ-7) were used to evaluate the subjective outcomes of stress urinary incontinence (SUI). Compared with the non-concomitant anti-incontinence group, the objective outcomes of reductive surgery exhibited no significant differences (100%, 78/78), and only the operation time of anti-incontinence group slightly increased 16 minutes. The occurrence rate of postoperative SUI was 12% (5/41), 15% (6/41), 17% (7/41) respectively after the operation at 2-month, 6-month and 12-month follow up in the non-concomitant anti-incontinence group; and the occurrence rate of the anti-incontinence group was 3% (1/37), 3% (1/37), 3% (1/37); but none of patients in the two groups require further surgery for stress urinary incontinence. Mean score of UDI-6 and IIQ-7 in all the patients decreased significantly after operation at 2-month, 6-month and 12-month follow up (all P statistic difference between the two groups (P > 0.05). It

A method of solution of the elastic-plastic thermal stress problem

International Nuclear Information System (INIS)

Rafalski, P.

1975-01-01

The purpose of the work is an improvement of the numerical technique for calculating the thermal stress distribution in an elastic-plastic structural element. The work consists of two parts. In the first a new method of solution of the thermal stress problem for the elastic-plastic body is presented. In the second a particular numerical technique, based on the above method, for calculating the stress and strain fields is proposed. A new mathematical approach consists in treating the stress and strain fields as mathematical objects defined in the space-time domain. The methods commonly applied use the stress and strain fields defined in the space domain and establish the relations between them at a given instant t. They reduce the problem to the system of ordinary differential equations with respect to time, which are usually solved with a step-by-step technique. The new method reduces the problem to the system of nonlinear algebraic equations. In the work the Hilbert space of admissible tensor fields is constructed. This space is the orthogonal sum of two subspaces: of statically admissible and kinematically admissible fields. Two alternative orthogonality conditions, which correspond to the equilibrium and compatibility equations with the appropriate boundary conditions, are derived. The results of the work are to be used for construction of the computer program for calculation the stress and strain fields in the elastic-plastic body with a prescribed temperature field in the interior and appropriate displacement and force conditions on the boundary

Perception of effects of auricular acupuncture on stress in receptionists of a hospital complex

Directory of Open Access Journals (Sweden)

Alessandra Faleiros Silveira

2018-01-01

Full Text Available Background and objectives: The stress is a reaction of organism that involves physical and psychological components and can tease changes in homeostasis of human body. This survey has intent to know the possible benefits of acupuncture on stress reduction, with the objective to evaluate the perceptions on levels of stress before and after eight weeks of an intervention of auricular acupuncture in receptionists of complex hospital. Methods: Participated in these study 24 receptionists of four units of a complex hospital situated in a municipality from the interior of Sao Paulo estate, which had an intervention in eight weeks with auricular acupuncture. To evaluate the perception of stress, they wrote their impressions about stress during the weekly meetings in order to change the needles. Results: According to the perception of most of the majority, the auricular acupuncture demonstrated benefits and changes in the way to deal with stressful situations day by day. They realized themselves calmer, with emotional control, presenting reduction of premenstrual syndrome symptoms and physical and mental well-being; however, for three participants the auricular acupuncture demonstrated few or none difference in reduction of stress. Conclusion: The auricular acupuncture intervention in this study demonstrate benefits on the reduction levels of stress, evidenced changes, not only in reduction stress, as also the perception of health in general.

A Non-parametric Method for Calculating Conditional Stressed Value at Risk

Directory of Open Access Journals (Sweden)

Kohei Marumo

2017-01-01

Full Text Available We consider the Value at Risk (VaR of a portfolio under stressed conditions. In practice, the stressed VaR (sVaR is commonly calculated using the data set that includes the stressed period. It tells us how much the risk amount increases if we use the stressed data set. In this paper, we consider the VaR under stress scenarios. Technically, this can be done by deriving the distribution of profit or loss conditioned on the value of risk factors. We use two methods; the one that uses the linear model and the one that uses the Hermite expansion discussed by Marumo and Wolff (2013, 2016. Numerical examples shows that the method using the Hermite expansion is capable of capturing the non-linear effects such as correlation collapse and volatility clustering, which are often observed in the markets.

Preliminary Investigation of Workplace-Provided Compressed Mindfulness-Based Stress Reduction with Pediatric Medical Social Workers.

Science.gov (United States)

Trowbridge, Kelly; Mische Lawson, Lisa; Andrews, Stephanie; Pecora, Jodi; Boyd, Sabra

2017-11-01

Mindfulness practices, including mindfulness meditation, show promise for decreasing stress among health care providers. This exploratory study investigates the feasibility of a two-day compressed mindfulness-based stress reduction (cMBSR) course provided in the hospital workplace with pediatric health care social workers. The standard course of Jon Kabat-Zinn's MBSR requires a participant commitment to eight weeks of instruction consisting of one 2.5-hour-per-week class, a single day retreat, and 45 minutes of practice for six of seven days each week. Commitments to family, work, caregiving, education, and so on, as well as limitations such as distance, may prevent health care providers from participating in a standard MBSR course. Using t tests, researchers measured the effect of cMBSR on (a) positive and negative experiences in pediatric social work, (b) perceived stress, (c) mindfulness, and (d) caring self-efficacy (as a component of patient- and family-centered care). Results included significant differences between the pre- and post-intervention outcome variables on the Professional Quality of Life Secondary Traumatic Stress subscale, the Mindful Attention and Awareness Scale, and the Caring Efficacy Scale. Findings found adequate evidence for the feasibility of cMBSR design and for a need of a more rigorous study of the effects of the cMBSR intervention. © 2017 National Association of Social Workers.

Expedited patient-specific assessment of contact stress exposure in the ankle joint following definitive articular fracture reduction.

Science.gov (United States)

Kern, Andrew M; Anderson, Donald D

2015-09-18

Acute injury severity, altered joint kinematics, and joint incongruity are three important mechanical factors linked to post-traumatic osteoarthritis (PTOA). Finite element analysis (FEA) was previously used to assess the influence of increased contact stress due to joint incongruity on PTOA development. While promising agreement with PTOA development was seen, the inherent complexities of contact FEA limited the numbers of subjects that could be analyzed. Discrete element analysis (DEA) is a simplified methodology for contact stress computation, which idealizes contact surfaces as a bed of independent linear springs. In this study, DEA was explored as an expedited alternative to FEA contact stress exposure computation. DEA was compared to FEA using results from a previously completed validation study of two cadaveric human ankles, as well as a previous study of post-operative contact stress exposure in 11 patients with tibial plafond fracture. DEA-computed maximum contact stresses were within 19% of those experimentally measured, with 90% of the contact area having computed contact stress values within 1MPa of those measured. In the 11 fractured ankles, maximum contact stress and contact area differences between DEA and FEA were 0.85 ± 0.64 MPa and 22.5 ± 11.5mm(2). As a predictive measure for PTOA development, both DEA and FEA had 100% concordance with presence of OA (KL grade ≥ 2) and >95% concordance with KL grade at 2 years. These results support DEA as a reasonable alternative to FEA for computing contact stress exposures following surgical reduction of a tibial plafond fracture. Copyright © 2015 Elsevier Ltd. All rights reserved.

Residual Stress Analysis Based on Acoustic and Optical Methods

Directory of Open Access Journals (Sweden)

Sanichiro Yoshida

2016-02-01

Full Text Available Co-application of acoustoelasticity and optical interferometry to residual stress analysis is discussed. The underlying idea is to combine the advantages of both methods. Acoustoelasticity is capable of evaluating a residual stress absolutely but it is a single point measurement. Optical interferometry is able to measure deformation yielding two-dimensional, full-field data, but it is not suitable for absolute evaluation of residual stresses. By theoretically relating the deformation data to residual stresses, and calibrating it with absolute residual stress evaluated at a reference point, it is possible to measure residual stresses quantitatively, nondestructively and two-dimensionally. The feasibility of the idea has been tested with a butt-jointed dissimilar plate specimen. A steel plate 18.5 mm wide, 50 mm long and 3.37 mm thick is braze-jointed to a cemented carbide plate of the same dimension along the 18.5 mm-side. Acoustoelasticity evaluates the elastic modulus at reference points via acoustic velocity measurement. A tensile load is applied to the specimen at a constant pulling rate in a stress range substantially lower than the yield stress. Optical interferometry measures the resulting acceleration field. Based on the theory of harmonic oscillation, the acceleration field is correlated to compressive and tensile residual stresses qualitatively. The acoustic and optical results show reasonable agreement in the compressive and tensile residual stresses, indicating the feasibility of the idea.

Methods of Model Reduction for Large-Scale Biological Systems: A Survey of Current Methods and Trends.

Science.gov (United States)

Snowden, Thomas J; van der Graaf, Piet H; Tindall, Marcus J

2017-07-01

Complex models of biochemical reaction systems have become increasingly common in the systems biology literature. The complexity of such models can present a number of obstacles for their practical use, often making problems difficult to intuit or computationally intractable. Methods of model reduction can be employed to alleviate the issue of complexity by seeking to eliminate those portions of a reaction network that have little or no effect upon the outcomes of interest, hence yielding simplified systems that retain an accurate predictive capacity. This review paper seeks to provide a brief overview of a range of such methods and their application in the context of biochemical reaction network models. To achieve this, we provide a brief mathematical account of the main methods including timescale exploitation approaches, reduction via sensitivity analysis, optimisation methods, lumping, and singular value decomposition-based approaches. Methods are reviewed in the context of large-scale systems biology type models, and future areas of research are briefly discussed.

Numerical comparison of robustness of some reduction methods in rough grids

KAUST Repository

Hou, Jiangyong; Sun, Shuyu; Chen, Zhangxin

2014-01-01

In this article, we present three nonsymmetric mixed hybrid RT 1 2 methods and compare with some recently developed reduction methods which are suitable for the single-phase Darcy flow problem with full anisotropic and highly heterogeneous

Cognitive behavioural therapy and mindfulness based stress reduction may be equally effective in reducing anxiety and depression in adults with autism spectrum disorders.

Science.gov (United States)

Sizoo, Bram B; Kuiper, Erik

2017-05-01

Anxiety and depression co-occur in 50-70% of adults with autism spectrum disorder (ASD) but treatment methods for these comorbid problems have not been systematically studied. Recently, two ASD-tailored protocols were published: mindfulness based stress reduction (MBSR) and cognitive behavioural therapy (CBT). We wanted to investigate if both methods are equally effective in reducing anxiety and depression symptoms among adults with ASD. 59 adults with ASD and anxiety or depression scores above 7 on the Hospital Anxiety and Depression Scale, gave informed consent to participate; 27 followed the CBT protocol, and 32 the MBSR treatment protocol. Anxiety and depression scores, autism symptoms, rumination, and global mood were registered at the start, at the end of the 13-week treatment period, and at 3-months follow-up. Irrational beliefs and mindful attention awareness were used as process measures during treatment and at follow-up. Results indicate that both MBSR and CBT are associated with a reduction in anxiety and depressive symptoms among adults with ASD, with a sustained effect at follow-up, but without a main effect for treatment group. A similar pattern was seen for the reduction of autistic symptoms, rumination and the improvement in global mood. There are some indications that MBSR may be preferred over CBT with respect to the treatment effect on anxiety when the scores on measures of irrational beliefs or positive global mood at baseline are high. Mindfulness and cognitive behavioral therapies are both promising treatment methods for reducing comorbid anxiety and depression in adults with ASD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Resveratrol Prevents Cardiovascular Complications in the SHR/STZ Rat by Reductions in Oxidative Stress and Inflammation

Directory of Open Access Journals (Sweden)

Rebecca K. Vella

2015-01-01

Full Text Available The cardioprotective effects of resveratrol are well established in animal models of metabolic disease but are yet to be investigated in a combined model of hypertension and diabetes. This study investigated the ability of resveratrol’s antioxidant and anti-inflammatory effects to prevent cardiovascular complications in the spontaneously hypertensive streptozotocin-induced diabetic rat. Diabetes was induced in eight-week-old male spontaneously hypertensive rats via a single intravenous injection of streptozotocin. Following this, resveratrol was administered orally for an eight-week period until the animals were sixteen weeks of age. Upon completion of the treatment regime assessments of oxidative stress, lipid peroxidation, inflammation, and cardiovascular function were made. Resveratrol administration to hypertensive-diabetic animals did not impact upon blood glucose or haemodynamics but significantly reduced oxidative stress, lipid peroxidation, and inflammatory cytokines. Reductions in systemic levels of oxidative stress and inflammation conferred improvements in vascular reactivity and left ventricular pump function and electrophysiology. This study demonstrates that resveratrol administration to hypertensive diabetic animals can elicit cardioprotective properties via antioxidant and anti-inflammatory effects. The observed preservation of cardiovascular function was independent of changes in blood glucose concentration and haemodynamics, suggesting that oxidative stress and inflammation are key components within the pathological cascade associated with hypertension and diabetes.

Psychotherapeutic Methods of Coping with Stress in Everyday Life

Directory of Open Access Journals (Sweden)

Senol TURAN

2015-12-01

Full Text Available Stress is an inevitable part of life. Knowing the ways of coping with stress are necessary to preserve our mental and physical health and to maintain good social and/or occupational functioning in daily life activities. Different ways of coping with stress have been developed throughout history. Various type of therapies offer quite effective remedies for coping with stress in everyday life. Among psychotherapeutic treatments cognitive behavioral therapy which involves teaching stressful individuals to develop coping strategies have yielded very promising results. It is helpful to determine first whether stress source can be changed, several therapeutic approaches may then be used. Lazarus and Folkman have identified two major approaches for coping with stress so-called "problem-focused" and "emotion-focused". In "problem-focused" approaches targets are acquiring time management, self-monitoring, problem-solving skills, while in "emotion-focused" approaches, through ways of accepting or rejecting of stress associated negative emotions, or reconciling with these emotions, the target is learning how to keep emotions under control. "Problem-focused" and "emotion-focused" approaches may independently be used effectively in appropriate cases, their simultaneous practice may increase chances of successful treatment. Apart from this methods, psychodynamic therapy may be indicated in some cases. [JCBPR 2015; 4(3.000: 133-140

Gene Expression Responses to FUS, EWS, and TAF15 Reduction and Stress Granule Sequestration Analyses Identifies FET-Protein Non-Redundant Functions

DEFF Research Database (Denmark)

Blechingberg, Jenny; Luo, Yonglun; Bolund, Lars

2012-01-01

The FET family of proteins is composed of FUS/TLS, EWS/EWSR1, and TAF15 and possesses RNA- and DNA-binding capacities. The FET-proteins are involved in transcriptional regulation and RNA processing, and FET-gene deregulation is associated with development of cancer and protein granule formations...... in amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and trinucleotide repeat expansion diseases. We here describe a comparative characterization of FET-protein localization and gene regulatory functions. We show that FUS and TAF15 locate to cellular stress granules to a larger extend than EWS....... FET-proteins have no major importance for stress granule formation and cellular stress responses, indicating that FET-protein stress granule association most likely is a downstream response to cellular stress. Gene expression analyses showed that the cellular response towards FUS and TAF15 reduction...

Preconditioning with Azadirachta indica ameliorates cardiorenal dysfunction through reduction in oxidative stress and extracellular signal regulated protein kinase signalling

Directory of Open Access Journals (Sweden)

Temidayo Olutayo Omóbòwálé

2016-10-01

Conclusions: Together, A. indica and vitamin C prevented IRI-induced cardiorenal dysfunction via reduction in oxidative stress, improvement in antioxidant defence system and increase in the ERK1/2 expressions. Therefore, A. indica can be a useful chemopreventive agent in the prevention and treatment of conditions associated with intestinal ischaemia-reperfusion injury.

The Impact of Mindfulness-Based Stress Reduction on Emotional Wellbeing and Glycemic Control of Patients with Type 2 Diabetes Mellitus

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A. Armani Kian

2018-01-01

Full Text Available Objective. The aim of the study was to determine the effect of mindfulness-based stress reduction (MBSR intervention on emotion regulation and glycemic control of patients with type 2 diabetes. Materials and Methods. Sixty patients with type 2 diabetes were recruited for this randomized controlled trial from an outpatient clinic at Imam Hospital in Iran. The intervention group participated in 8 sessions of MBSR, and the control group continued the treatment as usual. Fasting blood sugar and HbA1c were measured as two indices of glycemic control. Overall mental health, depression, and anxiety were measured using the General Health Questionnaire (GHQ-28, Hamilton Depression Rating Scale (HDRS, and Hamilton Anxiety Rating Scale (HARS, respectively. All the assessments were performed at baseline and after 8 weeks and 3 months as follow-up. Results. In comparison with the control group, the MBSR intervention group showed a significant reduction on all outcome measures including FBS, HbA1C, HARS, and HDRS scores (p<0/05. Conclusion. MBSR had a remarkable improvement on emotional wellbeing and glycemic control of patients with type 2 diabetes.

Stress analysis of thermal sprayed coatings using a semi-destructive hole-drilling strain gauge method

International Nuclear Information System (INIS)

Dolhof, V.; Musil, J.; Cepera, M.; Zeman, J.

1995-01-01

Residual stress is an important parameter in coating technology since it often relates to the maximum coating thickness which can be deposited without spallation, and this applies to coatings produced by different thermal spray and thin film technologies. Indeed, the mechanisms by which residual stress is built up or locked into a coating depends markedly on the deposition process and coating structure (growth structure, phase composition) in the same way too. Methods for determining residual stresses in materials include both destructive and non-destructive methods. This contribution describes semi-destructive hole-drilling strain gauge method modified for measurement of residual stresses in thermal sprayed coatings. This method of stress analysis was used for determination of stress levels in thermal sprayed WC-17% Co coatings onto 13% Cr steel substrates. Results show that deposition conditions and final coating structure influence directly the residual stress level in the coatings. It is proved that semi-destructive hole-tube drilling measurement is effective reproducible method of coating stress analysis and good solution for optimization of deposition process

Constitutive Modeling of the Flow Stress of GCr15 Continuous Casting Bloom in the Heavy Reduction Process

Science.gov (United States)

Ji, Cheng; Wang, Zilin; Wu, Chenhui; Zhu, Miaoyong

2018-04-01

According to the calculation results of a 3D thermomechanical-coupled finite-element (FE) model of GCr15 bearing steel bloom during a heavy reduction (HR) process, the variation ranges in the strain rate and strain under HR were described. In addition, the hot deformation behavior of the GCr15 bearing steel was studied over the temperature range from 1023 K to 1573 K (750 °C to 1300 °C) with strain rates of 0.001, 0.01, and 0.1 s-1 in single-pass thermosimulation compression experiments. To ensure the accuracy of the constitutive model, the temperature range was divided into two temperature intervals according to the fully austenitic temperature of GCr15 steel [1173 K (900 °C)]. Two sets of material parameters for the constitutive model were derived based on the true stress-strain curves of the two temperature intervals. A flow stress constitutive model was established using a revised Arrhenius-type constitutive equation, which considers the relationships among the material parameters and true strain. This equation describes dynamic softening during hot compression processes. Considering the effect of glide and climb on the deformation mechanism, the Arrhenius-type constitutive equation was modified by a physically based approach. This model is the most accurate over the temperatures ranging from 1173 K to 1573 K (900 °C to 1300 °C) under HR deformation conditions (ignoring the range from 1273 K to 1573 K (1000 °C to 1300 °C) with a strain rate of 0.1 s-1). To ensure the convergence of the FE calculation, an approximated method was used to estimate the flow stress at temperatures greater than 1573 K (1300 °C).

An exploratory study of Mindfulness Based Stress Reduction for emotional eating.

Science.gov (United States)

Levoy, Emily; Lazaridou, Asimina; Brewer, Judson; Fulwiler, Carl

2017-02-01

Emotional eating is an important predictor of weight loss and weight regain after weight loss. This two part study's primary aim was to explore changes in emotional eating in a general population of individuals taking the Mindfulness Based Stress Reduction (MBSR) program, with a secondary aim to explore whether changes in mindfulness predicted changes in emotional eating. Self-reported survey data exploring these questions were collected before and after the intervention for two sequential studies (Study 1 and Study 2). While there were no control groups for either study, in both studies emotional eating scores following the MBSR were significantly lower than scores prior to taking the MBSR (p mindfulness were correlated with changes in emotional eating (r = 0.317, p = 0.004). These results suggest that MBSR may be an effective intervention for emotional eating, and that further research is warranted to examine effects on weight loss and maintenance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical activity, mindfulness meditation, or heart rate variability biofeedback for stress reduction: a randomized controlled trial

NARCIS (Netherlands)

van der Zwan, J.E.; de Vente, W.; Huizink, A.C.; Bögels, S.M.; de Bruin, E.I.

2015-01-01

In contemporary western societies stress is highly prevalent, therefore the need for stress-reducing methods is great. This randomized controlled trial compared the efficacy of self-help physical activity (PA), mindfulness meditation (MM), and heart rate variability biofeedback (HRV-BF) in reducing

A new uncertainty reduction method for PWR cores with erbia bearing fuel

International Nuclear Information System (INIS)

Takeda, Toshikazu; Sano, Tadafumi; Kitada, Takanori; Kuroishi, Takeshi; Yamasaki, Masatoshi; Unesaki, Hironobu

2008-01-01

The concept of a PWR with erbia bearing high burnup fuel has been proposed. The erbia is added to all fuel with over 5% 235 U enrichment to retain the neutronics characteristics to that within 5% 235 U enrichment. There is a problem of the prediction accuracy of the neutronics characteristics with erbia bearing fuel because of the short of experimental data of erbia bearing fuel. The purpose of the present work is to reduce the uncertainty. A new method has been proposed by combining the bias factor method and the cross section adjustment method. For the PWR core, the uncertainty reduction, which shows the rate of reduction of uncertainty, of the k eff is 0.865 by the present method and 0.801 by the conventional bias factor method. Thus the prediction uncertainties are reduced by the present method compared to the bias factor method. (authors)

Proposal on the mitigation methods of thermal stress near the sodium

International Nuclear Information System (INIS)

Ando, Masanori; Kasahara, Naoto

2003-09-01

A Reactor vessel of fast rector plants contains high temperature liquid sodium in its inside and its upper end is supported by a low temperature structures. Therefore, a significant temperature gradient will arise at the vessel wall near the sodium surface. For this reason, a large thermal stress will be generated around this part. To lower this stress and to protect the vessel, a number of methods have been applied the plants. Generally, these mitigation methods by protection equipments for thermal stress also have some problems such as, increase a mount of materials or to be complicate for control, hard to maintenance and so on. In this research, authors suggested another simple methods for thermal stress, and evaluated their effects using computer analysis. The results obtained in this research are as follows. Authors suggested one method, circulate high temperature gas around outside of the vessel and evaluated the effects of this method by analysis. In case of using this method, Sn (one of index values of design) value might be getting lower about 45%. Authors also suggested another method by setting up a heat transfer plate outside of the vessel and evaluated the effects of this method by analysis. Effects of this method depend on material of the plate. In case of using Carbon as material of plate, Sn value might be 27% lower and in case of using 12Cr steel as material of plate, Sn value might be 15% lower. Authors also suggested another method by changing material of the guard vessel to be the one which has good ability of heat transfer and evaluated the effects of this method by analysis. In case of changing material of guard vessel to 12Cr steel, Sn value might be lower about 12%. (author)

Mitigation method of thermal transient stress by thermalhydraulic-structure total analysis

International Nuclear Information System (INIS)

Kasahara, Naoto; Jinbo, Masakazu; Hosogai, Hiromi

2003-01-01

This study proposes a rational evaluation and mitigation method of thermal transient loads in fast reactor components by utilizing relationships among plant system parameters and stresses induced by thermal transients of plants. A thermalhydraulic-structure total analysis procedure helps us to grasp relationship among system parameters and thermal stresses. Furthermore, it enables mitigation of thermal transient loads by adjusting system parameters. In order to overcome huge computations, a thermalhydraulic-structure total analysis code and the Design of Experiments methodology are utilized. The efficiency of the proposed mitigation method is validated through thermal stress evaluation of an intermediate heat exchanger in Japanese demonstration fast reactor. (author)

Reproduction is associated with a tissue-dependent reduction of oxidative stress in eusocial female Damaraland mole-rats (Fukomys damarensis.

Directory of Open Access Journals (Sweden)

Christina M Schmidt

Full Text Available Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal's lifespan. Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage (malondialdehyde, MDA; protein carbonyls, PC and antioxidants (total antioxidant capacity, TAC; superoxide dismutase, SOD in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females may be attributable to the unusual social structure of this species, as similar relationships have been observed between reproductive and non-reproductive eusocial insects.

Residual stress measurement by X-ray diffraction with the Gaussian curve method and its automation

International Nuclear Information System (INIS)

Kurita, M.

1987-01-01

X-ray technique with the Gaussian curve method and its automation are described for rapid and nondestructive measurement of residual stress. A simplified equation for measuring the stress by the Gaussian curve method is derived because in its previous form this method required laborious calculation. The residual stress can be measured in a few minutes, depending on materials, using an automated X-ray stress analyzer with a microcomputer which was developed in the laboratory. The residual stress distribution of a partially induction hardened and tempered (at 280 0 C) steel bar was measured with the Gaussian curve method. A sharp residual tensile stress peak of 182 MPa appeared right outside the hardened region at which fatigue failure is liable to occur

Depression, Anxiety and Stress Reduction in Medical Education: Humor as an Intervention

Directory of Open Access Journals (Sweden)

Ramesh Narula

2011-04-01

Full Text Available Background: In recent years there has been a growing appreciation of the issues of quality of life and stresses involved in medical training as this may affect their learning and academic performance. Objective of the study was to explore the effectiveness of humor when used as intervention in large group teaching over negative emotions amongst students. Method: The present Interventional, Randomized control trial study was carried out on medical students of 4th Semester of RMCH, Bareilly, which has total 90 students. Using simple random sampling lottery method the whole class was divided in two groups-A and B consisting of 45 students each. Group A as control group and Group B experimental group. In first and last lecture of both groups Dass-21 was used as measuring scale, for depression, anxiety and stress and results were compared to see the effect of humor on these three negative emotions. Result: Comparison of Severe and Extremely severe Stress: In Group A 40.54% in class -1 increased to 47.54% in class- 4, while in group B initial 13.15 % was reduced to 0 % (highly significant. Anxiety: In group A, after Class 1 -57.45% increased to 61.11% after class 4, while in group B, after class 1- 23.68% reduced to 2.27% only (highly significant. Depression: In group A, after Class 1 - 40.53% & 41.66 % after class 4 (not significant, while in group B, after class 1- 18.41% reduced to 0% (highly significant. Conclusion: In present study humor was found to be very effective intervention in relieving students on their negative emotions of depression, anxiety and stress to a larger extent. Further research would justify the use of humor as an effective teaching aid in medical education.

Effects of Adiponectin Including Reduction of Androstenedione Secretion and Ovarian Oxidative Stress Parameters In Vivo.

Directory of Open Access Journals (Sweden)

Fabio V Comim

Full Text Available Adiponectin is the most abundantly produced human adipokine with anti-inflammatory, anti-oxidative, and insulin-sensitizing properties. Evidence from in vitro studies has indicated that adiponectin has a potential role in reproduction because it reduces the production of androstenedione in bovine theca cells in vitro. However, this effect on androgen production has not yet been observed in vivo. The current study evaluated the effect of adiponectin on androstenedione secretion and oxidative stress parameters in a rodent model. Seven-week-old female Balb/c mice (n = 33, previously treated with equine gonadotropin chorionic, were assigned to one of four different treatments: Group 1, control (phosphate-buffered saline; Group 2, adiponectin 0.1 μg/mL; Group 3, adiponectin 1.0 μg/mL; Group 4, adiponectin 5.0 μg/mL. After 24 h, all animals were euthanized and androstenedione levels were measured in the serum while oxidative stress markers were quantified in whole ovary tissue. Female mice treated with adiponectin exhibited a significant reduction (about 60% in serum androstenedione levels in comparison to controls. Androstenedione levels decreased from 0.78 ± 0.4 ng/mL (mean ± SD in controls to 0.28 ± 0.06 ng/mL after adiponectin (5 μg/mL treatment (P = 0.01. This change in androgen secretion after 24 hours of treatment was associated with a significant reduction in the expression of CYP11A1 and STAR (but not CYP17A1. In addition, ovarian AOPP product levels, a direct product of protein oxidation, decreased significantly in adiponectin-treated mice (5 μg/mL; AOPP (mean ± SD decreased to 4.3 ± 2.1 μmol/L in comparison with that of the controls (11.5 ± 1.7 μmol/L; P = 0.0003. Our results demonstrated for the first time that acute treatment with adiponectin reduced the levels of a direct oxidative stress marker in the ovary as well as decreased androstenedione serum levels in vivo after 24 h.

A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress

Science.gov (United States)

Tchitchekova, Deyana S.; Morthomas, Julien; Ribeiro, Fabienne; Ducher, Roland; Perez, Michel

2014-07-01

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ˜3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.

A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress

International Nuclear Information System (INIS)

Tchitchekova, Deyana S.; Morthomas, Julien; Perez, Michel; Ribeiro, Fabienne; Ducher, Roland

2014-01-01

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ∼3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress

A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress

Energy Technology Data Exchange (ETDEWEB)

Tchitchekova, Deyana S. [IRSN, PSN, SEMIA, LPTM, Saint-Paul-Lez-Durance (France); Univ. Lyon, INSA Lyon, MATEIS, UMR CNRS 5510, Villeurbanne (France); Morthomas, Julien; Perez, Michel [Univ. Lyon, INSA Lyon, MATEIS, UMR CNRS 5510, Villeurbanne (France); Ribeiro, Fabienne [IRSN, PSN, SEMIA, LPTM, Saint-Paul-Lez-Durance (France); Ducher, Roland [IRSN, PSN, SAG, LETR, Saint-Paul-Lez-Durance (France)

2014-07-21

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ∼3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.

The effects of a mindfulness meditation-based stress reduction program on mood and symptoms of stress in cancer outpatients: 6-month follow-up.

Science.gov (United States)

Carlson, L E; Ursuliak, Z; Goodey, E; Angen, M; Speca, M

2001-03-01

The goals of this work were to assess the effects of participation in a mindfulness meditation-based stress reduction program on mood disturbance and symptoms of stress in cancer outpatients immediately after and 6 months after program completion. A convenience sample of eligible cancer patients were enrolled after they had given informed consent. All patients completed the Profile of Mood States (POMS) and Symptoms of Stress Inventory (SOSI) both before and after the intervention and 6 months later. The intervention consisted of a mindfulness meditation group lasting 1.5 h each week for 7 weeks, plus daily home meditation practice. A total of 89 patients, average age 51, provided pre-intervention data. Eighty patients provided post-intervention data, and 54 completed the 6-month follow-up The participants were heterogeneous with respect to type and stage of cancer. Patients' scores decreased significantly from before to after the intervention on the POMS and SOSI total scores and most subscales, indicating less mood disturbance and fewer symptoms of stress, and these improvements were maintained at the 6-month follow-up. More advanced stages of cancer were associated with less initial mood disturbance, while more home practice and higher initial POMS scores predicted improvements on the POMS between the pre- and post-intervention scores. Female gender and more education were associated with higher initial SOSI scores, and improvements on the SOSI were predicted by more education and greater initial mood disturbance. This program was effective in decreasing mood disturbance and stress symptoms for up to 6 months in both male and female patients with a wide variety of cancer diagnoses, stages of illness, and educational background, and with disparate ages.

Effect of silicon and nanosilicon on reduction of damage caused by salt stress in maize (Zea mays seedlings

Directory of Open Access Journals (Sweden)

Assieh Behdad

2015-12-01

Full Text Available Salinity reduced the efficiency of agricultural production like maize as one of the most important cereals for food and oil for humans. Silicon is the second most abundant element in the soil and alleviates the biotic and abiotic stresses in plants. The aim of this study is evaluate the effect of silicon and nanosilicon on improvement of salt stress in maize (Zea mays. For this propose, the interaction between the effects of different levels of salinity (0 and 100 mM, silicon and nanosilicon (50, 100 and 150 mg /mL was studied in completely randomized block design with factorial experiments and with three replications. The results showed that salinity significantly decreased root and shoot growth, amount of chlorophyll and carotenoid pigments, protein and potassium contents, compared to control. Treating plants with silicon and nanosilicon caused reduction of salinity effects and increase above indices. Salinity stress also caused a significant increase in proline, anthocyanin and soluble carbohydrate contents, lipid peroxidation, and catalase activity and treatment with silicon and nanosilicon alleviates effects of salt stress and reduced the amount of above indices. 150 mg/mL of nanosilicon showed the maximum effect on diminishing negative effects of salt stress on all examined parameters. So, the use of this element is proposed as alleviator of salt stress on maize.

A New Method of Stress Measurement Based upon Elastic Deformation of Core Sample with Stress Relief by Drilling

Science.gov (United States)

Ito, T.; Funato, A.; Tamagawa, T.; Tezuka, K.; Yabe, Y.; Abe, S.; Ishida, A.; Ogasawara, H.

2017-12-01

When rock is cored at depth by drilling, anisotropic expansion occurs with the relief of anisotropic rock stresses, resulting in a sinusoidal variation of core diameter with a period of 180 deg. in the core roll angle. The circumferential variation of core diameter is given theoretically as a function of rock stresses. These new findings can lead various ideas to estimate the rock stress from circumferential variation of core diameter measured after the core retrieving. In the simplest case when a single core sample is only available, the difference between the maximum and minimum components of rock stress in a plane perpendicular to the drilled hole can be estimated from the maximum and minimum core diameters (see the detail in, Funato and Ito, IJRMMS, 2017). The advantages of this method include, (i) much easier measurement operation than those in other in-situ or in-lab estimation methods, and (ii) applicability in high stress environment where stress measurements need pressure for packers or pumping system for the hydro-fracturing methods higher than their tolerance levels. We have successfully tested the method at deep seismogenic zones in South African gold mines, and we are going to apply it to boreholes collared at 3 km depth and intersecting a M5.5 rupture plane several hundred meters below the mine workings in the ICDP project of "Drilling into Seismogenic zones of M2.0 - M5.5 earthquakes in deep South African gold mines" (DSeis) (e.g., http://www.icdp-online.org/projects/world/africa/orkney-s-africa/details/). If several core samples with different orientation are available, all of three principal components of 3D rock stress can be estimated. To realize this, we should have several boreholes drilled in different directions in a rock mass where the stress field is considered to be uniform. It is commonly carried out to dill boreholes in different directions from a mine gallery. Even in a deep borehole drilled vertically from the ground surface, the

Development of stress relaxation measurement by a small size C-ring specimen method

International Nuclear Information System (INIS)

Shimanuki, Shizuka; Nakata, Kiyotomo; Kasahara, Shigeki; Kuniya, Jiro

2002-01-01

A stress relaxation measurement method has been developed by using C-ring specimens, and a specimen size effect has been evaluated taking radiation-induced stress relaxation into consideration. C-ring specimens were stressed by forcing a wedge in the gap. Giving an appropriate eccentric configuration in the half of the ring opposite the gap, the stress gradient along the circumference was eliminated in the section and the stress level could be varied by changing the gap spacing. The validity of the C-ring test method was confirmed by thermally stress relaxation experiments at annealing temperatures from 300 to 600degC for 1 min to 200 h in carbon steel: considerable stress relaxation could be measured for all levels of applied stress even at relatively low annealing temperatures. The relaxation results obtained from the C-ring test were in good agreement with those from a uniaxial tensile stress relaxation test. The smaller C-ring specimen with about 40 mm diameter, which is required for radiation-induced stress relaxation test, also showed adequate accuracy on stress relaxation at 600 to 830degC in stainless steel, compared with the large size C-ring specimen test. (author)

Microbial activity in aquatic environments measured by dimethyl sulfoxide reduction and intercomparison with commonly used methods.

Science.gov (United States)

Griebler, C; Slezak, D

2001-01-01

A new method to determine microbial (bacterial and fungal) activity in various freshwater habitats is described. Based on microbial reduction of dimethyl sulfoxide (DMSO) to dimethyl sulfide (DMS), our DMSO reduction method allows measurement of the respiratory activity in interstitial water, as well as in the water column. DMSO is added to water samples at a concentration (0.75% [vol/vol] or 106 mM) high enough to compete with other naturally occurring electron acceptors, as determined with oxygen and nitrate, without stimulating or inhibiting microbial activity. Addition of NaN(3), KCN, and formaldehyde, as well as autoclaving, inhibited the production of DMS, which proves that the reduction of DMSO is a biotic process. DMSO reduction is readily detectable via the formation of DMS even at low microbial activities. All water samples showed significant DMSO reduction over several hours. Microbially reduced DMSO is recovered in the form of DMS from water samples by a purge and trap system and is quantified by gas chromatography and detection with a flame photometric detector. The DMSO reduction method was compared with other methods commonly used for assessment of microbial activity. DMSO reduction activity correlated well with bacterial production in predator-free batch cultures. Cell-production-specific DMSO reduction rates did not differ significantly in batch cultures with different nutrient regimes but were different in different growth phases. Overall, a cell-production-specific DMSO reduction rate of 1.26 x 10(-17) +/- 0. 12 x 10(-17) mol of DMS per produced cell (mean +/- standard error; R(2) = 0.78) was calculated. We suggest that the relationship of DMSO reduction rates to thymidine and leucine incorporation is linear (the R(2) values ranged from 0.783 to 0.944), whereas there is an exponential relationship between DMSO reduction rates and glucose uptake, as well as incorporation (the R(2) values ranged from 0.821 to 0.931). Based on our results, we

Application of nonlinear ultrasonic method for monitoring of stress state in concrete

International Nuclear Information System (INIS)

Kim, Gyu Jin; Kwak, Hyo Gyoung; Park, Sun Jong

2016-01-01

As the lifespan of concrete structures increases, their load carrying capacity decreases owing to cyclic loads and long-term effects such as creep and shrinkage. For these reasons, there is a necessity for stress state monitoring of concrete members. Particularly, it is necessary to evaluate the concrete structures for behavioral changes by using a technique that can overcome the measuring limitations of usual ultrasonic nondestructive evaluation methods. This paper proposes the use of a nonlinear ultrasonic method, namely, nonlinear resonant ultrasonic spectroscopy (NRUS) for the measurement of nonlinearity parameters for stress monitoring. An experiment compared the use of NRUS method and a linear ultrasonic method, namely, ultrasonic pulse velocity (UPV) to study the effects of continuously increasing loads and cyclic loads on the nonlinearity parameter. Both NRUS and UPV methods found a similar direct relationship between load level and that parameter. The NRUS method showed a higher sensitivity to micro-structural changes of concrete than UPV method. Thus, the experiment confirms the possibility of using the nonlinear ultrasonic method for stress state monitoring of concrete members

Application of nonlinear ultrasonic method for monitoring of stress state in concrete

Energy Technology Data Exchange (ETDEWEB)

Kim, Gyu Jin; Kwak, Hyo Gyoung [Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park, Sun Jong [Dept. of Structural System and Site Safety Evaluation, Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2016-04-15

As the lifespan of concrete structures increases, their load carrying capacity decreases owing to cyclic loads and long-term effects such as creep and shrinkage. For these reasons, there is a necessity for stress state monitoring of concrete members. Particularly, it is necessary to evaluate the concrete structures for behavioral changes by using a technique that can overcome the measuring limitations of usual ultrasonic nondestructive evaluation methods. This paper proposes the use of a nonlinear ultrasonic method, namely, nonlinear resonant ultrasonic spectroscopy (NRUS) for the measurement of nonlinearity parameters for stress monitoring. An experiment compared the use of NRUS method and a linear ultrasonic method, namely, ultrasonic pulse velocity (UPV) to study the effects of continuously increasing loads and cyclic loads on the nonlinearity parameter. Both NRUS and UPV methods found a similar direct relationship between load level and that parameter. The NRUS method showed a higher sensitivity to micro-structural changes of concrete than UPV method. Thus, the experiment confirms the possibility of using the nonlinear ultrasonic method for stress state monitoring of concrete members.

Investigation of stress distribution in normal and oblique partial penetration. Welded nozzles by 3-D photoelastic stress freezing method

International Nuclear Information System (INIS)

Miyamoto, H.; Kubo, M.; Katori, T.

1981-01-01

Experimental investigation by 3-D photoelasticity has been carried out to measure the stress distribution of partial penetration welded nozzles attached to the bottom head of a pressure vessel. A 3-D photoelastic stress freezing method was chosen as the most effective means of observation of the stress distribution in the vicinity of the nozzle/wall weld. The experimental model was a 1:20 scale spherical bottom head. Both an axisymmetric nozzle and an asymmetric nozzle were investigated. Epoxy resin, which is a thermosetting plastic, was used as the model material. The oblique effect was examined by comparing the stress distribution of the asymmetric nozzle with that of the axisymmetric nozzle. Furthermore, the experimental results were compared with the analytical results using 3-D finite element method (FEM). The stress distributions obtained from the frozen fringe pattern of the 3-D photoelastic model were in good agreement with those by 3-D FEM. (orig.)

An evaluation of three commercially available metal artifact reduction methods for CT imaging

International Nuclear Information System (INIS)

Huang, Jessie Y; Kerns, James R; Balter, Peter A; Followill, David S; Mirkovic, Dragan; Howell, Rebecca M; Kry, Stephen F; Nute, Jessica L; Liu, Xinming; Stingo, Francesco C

2015-01-01

Three commercial metal artifact reduction methods were evaluated for use in computed tomography (CT) imaging in the presence of clinically realistic metal implants: Philips O-MAR, GE’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI monochromatic imaging with metal artifact reduction software applied (MARs). Each method was evaluated according to CT number accuracy, metal size accuracy, and streak artifact severity reduction by using several phantoms, including three anthropomorphic phantoms containing metal implants (hip prosthesis, dental fillings and spinal fixation rods). All three methods showed varying degrees of success for the hip prosthesis and spinal fixation rod cases, while none were particularly beneficial for dental artifacts. Limitations of the methods were also observed. MARs underestimated the size of metal implants and introduced new artifacts in imaging planes beyond the metal implant when applied to dental artifacts, and both the O-MAR and MARs algorithms induced artifacts for spinal fixation rods in a thoracic phantom. Our findings suggest that all three artifact mitigation methods may benefit patients with metal implants, though they should be used with caution in certain scenarios. (paper)

A general mixed boundary model reduction method for component mode synthesis

NARCIS (Netherlands)

Voormeeren, S.N.; Van der Valk, P.L.C.; Rixen, D.J.

2010-01-01

A classic issue in component mode synthesis (CMS) methods is the choice for fixed or free boundary conditions at the interface degrees of freedom (DoF) and the associated vibration modes in the components reduction base. In this paper, a novel mixed boundary CMS method called the “Mixed

An indigenous method for closed reduction of pediatric mandibular parasymphysis fracture.

Science.gov (United States)

Kumar, Naresh; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal

2015-01-01

Mandibular fractures in children are very rare as compared to adults due to protected anatomic features of child and less exposure to road traffic accidents. Management becomes complicated due to inherent dynamic nature, instability of mixed dentition and fear of surgery. Conservative management can be done with the help of acrylic cap splints along with circum-mandibular wiring, intermaxillary fixation with eyelet wires, arch wires or open reduction and internal fixation with bio-resorbable plates. Different methods have various pros and cons. The choice of anesthesia is also very crucial sometimes. This case report describes a new method of closed reduction with 18 gauge needle simulated as an arch bar performed under local anaesthesia.

Prediction of residual stress using explicit finite element method

Directory of Open Access Journals (Sweden)

W.A. Siswanto

2015-12-01

Full Text Available This paper presents the residual stress behaviour under various values of friction coefficients and scratching displacement amplitudes. The investigation is based on numerical solution using explicit finite element method in quasi-static condition. Two different aeroengine materials, i.e. Super CMV (Cr-Mo-V and Titanium alloys (Ti-6Al-4V, are examined. The usage of FEM analysis in plate under normal contact is validated with Hertzian theoretical solution in terms of contact pressure distributions. The residual stress distributions along with normal and shear stresses on elastic and plastic regimes of the materials are studied for a simple cylinder-on-flat contact configuration model subjected to normal loading, scratching and followed by unloading. The investigated friction coefficients are 0.3, 0.6 and 0.9, while scratching displacement amplitudes are 0.05 mm, 0.10 mm and 0.20 mm respectively. It is found that friction coefficient of 0.6 results in higher residual stress for both materials. Meanwhile, the predicted residual stress is proportional to the scratching displacement amplitude, higher displacement amplitude, resulting in higher residual stress. It is found that less residual stress is predicted on Super CMV material compared to Ti-6Al-4V material because of its high yield stress and ultimate strength. Super CMV material with friction coefficient of 0.3 and scratching displacement amplitude of 0.10 mm is recommended to be used in contact engineering applications due to its minimum possibility of fatigue.

Thermodynamic method for generating random stress distributions on an earthquake fault

Science.gov (United States)

Barall, Michael; Harris, Ruth A.

2012-01-01

This report presents a new method for generating random stress distributions on an earthquake fault, suitable for use as initial conditions in a dynamic rupture simulation. The method employs concepts from thermodynamics and statistical mechanics. A pattern of fault slip is considered to be analogous to a micro-state of a thermodynamic system. The energy of the micro-state is taken to be the elastic energy stored in the surrounding medium. Then, the Boltzmann distribution gives the probability of a given pattern of fault slip and stress. We show how to decompose the system into independent degrees of freedom, which makes it computationally feasible to select a random state. However, due to the equipartition theorem, straightforward application of the Boltzmann distribution leads to a divergence which predicts infinite stress. To avoid equipartition, we show that the finite strength of the fault acts to restrict the possible states of the system. By analyzing a set of earthquake scaling relations, we derive a new formula for the expected power spectral density of the stress distribution, which allows us to construct a computer algorithm free of infinities. We then present a new technique for controlling the extent of the rupture by generating a random stress distribution thousands of times larger than the fault surface, and selecting a portion which, by chance, has a positive stress perturbation of the desired size. Finally, we present a new two-stage nucleation method that combines a small zone of forced rupture with a larger zone of reduced fracture energy.

Method for accelerated aging under combined environmental stress conditions

International Nuclear Information System (INIS)

Gillen, K.T.

1979-01-01

An accelerated aging method which can be used to simulate aging in combined stress environment situations is described. It is shown how the assumptions of the method can be tested experimentally. Aging data for a chloroprene cable jacketing material in single and combined radiation and temperature environments are analyzed and it is shown that these data offer evidence for the validity of the method

Primary teachers' knowledge and acquisition of stress relieving strategies.

Science.gov (United States)

Cockburn, A D

1996-09-01

Over the last 20 years there have been numerous studies of teacher stress but little is known of how teachers acquire coping strategies; their knowledge of those available to them and their opinion of these techniques. A total of 335 Norfolk primary teachers responded to a postal questionnaire providing biographical details; levels of job satisfaction and work related stress; responses to a range of commonly advocated techniques to reduce teacher stress and their opinion on who-if anyone-should take more responsibility for reducing teacher stress. On average the respondents were aware of 35 stress reduction strategies. The most effective strategies were ensuring that one understood what one was about to teach and thorough lesson preparation. A significant proportion of practitioners said that they would not consider seeking expert sources of advice. A total of 89 per cent of practitioners reported that they acquired at least some strategies through their own experience. It was concluded that the issue of teacher stress needs to be considered at governmental, school and individual levels. In the light of some resistance to traditional methods of stress reduction, the implications for initial and in-service training were explored.

Stress Reduction at the Work-Family Interface: Positive Parenting and Self-Efficacy as Mechanisms of Change in Workplace Triple P

Science.gov (United States)

Hartung, Doreen; Hahlweg, Kurt

2011-01-01

Workplace Triple P (WPTP) is a group-based parenting skills training specifically designed to meet the needs of employed parents. Several randomized controlled trials have demonstrated the training's efficacy. This study examined possible mechanisms of change that account for the stress reduction effects of this parenting skills training at the…

Stress recovery techniques for natural element method in 2-D solid mechanics

Energy Technology Data Exchange (ETDEWEB)

Cho, Jin Rae [Dept. of Naval Architecture and Ocean Engineering, Hongik University, Sejong (Korea, Republic of)

2016-11-15

This paper is concerned with the stress recovery for the natural element method in which the problem domain is discretized with Delaunay triangles and the structural behavior is approximated with Laplace interpolation functions. Basically, the global and local patch recovery techniques based on the L2-projection method are adopted. For the local patch recovery, the local element patches are defined by the supports of each Laplace interpolation function. For the comparison purpose, the local stress recovery is also performed using Lagrange-type basis functions that are used for 3- and 6-node triangular elements. The stresses that are recovered by the present global and local recovery techniques are compared each other and compared with the available analytic solution, in terms of their spatial distributions and the convergence rates. As well, the dependence of the recovered stress field on the type of test basis functions that are used forbnov-Galerkin (BG) and Petrov-Galerkin (PG) natural element methods is also investigated.

Calculation method for residual stress analysis of filament-wound spherical pressure vessels

International Nuclear Information System (INIS)

Knight, C.E. Jr.

1976-01-01

Filament wound spherical pressure vessels may be produced with very high performance factors. These performance factors are a calculation of contained pressure times enclosed volume divided by structure weight. A number of parameters are important in determining the level of performance achieved. One of these is the residual stress state in the fabricated unit. A significant level of an unfavorable residual stress state could seriously impair the performance of the vessel. Residual stresses are of more concern for vessels with relatively thick walls and/or vessels constructed with the highly anisotropic graphite or aramid fibers. A method is established for measuring these stresses. A theoretical model of the composite structure is required. Data collection procedures and techniques are developed. The data are reduced by means of the model and result in the residual stress analysis. The analysis method can be used in process parameter studies to establish the best fabrication procedures

Computational fluid dynamics (CFD) insights into agitation stress methods in biopharmaceutical development.

Science.gov (United States)

Bai, Ge; Bee, Jared S; Biddlecombe, James G; Chen, Quanmin; Leach, W Thomas

2012-02-28

Agitation of small amounts of liquid is performed routinely in biopharmaceutical process, formulation, and packaging development. Protein degradation commonly results from agitation, but the specific stress responsible or degradation mechanism is usually not well understood. Characterization of the agitation stress methods is critical to identifying protein degradation mechanisms or specific sensitivities. In this study, computational fluid dynamics (CFD) was used to model agitation of 1 mL of fluid by four types of common laboratory agitation instruments, including a rotator, orbital shaker, magnetic stirrer and vortex mixer. Fluid stresses in the bulk liquid and near interfaces were identified, quantified and compared. The vortex mixer provides the most intense stresses overall, while the stir bar system presented locally intense shear proximal to the hydrophobic stir bar surface. The rotator provides gentler fluid stresses, but the air-water interfacial area and surface stresses are relatively high given its low rotational frequency. The orbital shaker provides intermediate-level stresses but with the advantage of a large stable platform for consistent vial-to-vial homogeneity. Selection of experimental agitation methods with targeted types and intensities of stresses can facilitate better understanding of protein degradation mechanisms and predictability for "real world" applications. Copyright © 2011 Elsevier B.V. All rights reserved.

The effectiveness of stress inoculation group training (SIT on reducing job stress of employees of RAZAK pharmaceutical company in Tehran

Directory of Open Access Journals (Sweden)

M. Soudani

2011-01-01

Full Text Available Background and aims Despite the fact that work is the major part of human life and the source of satisfying the sense of idealism, innovation and the feeling of consent in the individual, but it is one of the most important factors of creating stress in today's societies. One of the most efficient methods of interfering in stress inoculation group training (SIT. The aim of the present research is the investigation of the efficacy of the stress inoculation group training (SIT on reducing career stress of employees of Razak Co.'s employees.     Methodsthis study is an intermediary study and the research method is experimental of pretest and posttest type with control group. 46 of subjects whose score in career stress test was above the average score were selected as sample, and were replaced in simple random way in two groups of test and control. 8-session test group of 1.5 hours each received team immunity training against stress. Both groups were tested and evaluated three times at the same time (pretest, posttest and follow up.   Resultsafter adjusting the posttest scores based on pretest scores, the results of one-way covariance pretest showed that stress inoculation group training (SIT had a meaningful influence on reduction of career stress on employees. Also the results of multivariable covariance analysis (Mankoa showed that this effect existed in every component of career stress, i.e. exceeding accountability, responsibility of others, very high working pressure, decision making that influences the others, and understanding of self as an individual not quite competent and qualified. In follow up studies after one month, the results showed that stress inoculation group training (SIT has a stable influence on reduction of career stress and it components.   Conclusion on the base of the obtained findings from research and effectiveness from the stress inoculation group training (SIT , it is recommended to apply this therapeutic

A general mixed boundary model reduction method for component mode synthesis

International Nuclear Information System (INIS)

Voormeeren, S N; Van der Valk, P L C; Rixen, D J

2010-01-01

A classic issue in component mode synthesis (CMS) methods is the choice for fixed or free boundary conditions at the interface degrees of freedom (DoF) and the associated vibration modes in the components reduction base. In this paper, a novel mixed boundary CMS method called the 'Mixed Craig-Bampton' method is proposed. The method is derived by dividing the substructure DoF into a set of internal DoF, free interface DoF and fixed interface DoF. To this end a simple but effective scheme is introduced that, for every pair of interface DoF, selects a free or fixed boundary condition for each DoF individually. Based on this selection a reduction basis is computed consisting of vibration modes, static constraint modes and static residual flexibility modes. In order to assemble the reduced substructures a novel mixed assembly procedure is developed. It is shown that this approach leads to relatively sparse reduced matrices, whereas other mixed boundary methods often lead to full matrices. As such, the Mixed Craig-Bampton method forms a natural generalization of the classic Craig-Bampton and more recent Dual Craig-Bampton methods. Finally, the method is applied to a finite element test model. Analysis reveals that the proposed method has comparable or better accuracy and superior versatility with respect to the existing methods.

Discrete element analysis is a valid method for computing joint contact stress in the hip before and after acetabular fracture.

Science.gov (United States)

Townsend, Kevin C; Thomas-Aitken, Holly D; Rudert, M James; Kern, Andrew M; Willey, Michael C; Anderson, Donald D; Goetz, Jessica E

2018-01-23

Evaluation of abnormalities in joint contact stress that develop after inaccurate reduction of an acetabular fracture may provide a potential means for predicting the risk of developing post-traumatic osteoarthritis. Discrete element analysis (DEA) is a computational technique for calculating intra-articular contact stress distributions in a fraction of the time required to obtain the same information using the more commonly employed finite element analysis technique. The goal of this work was to validate the accuracy of DEA-computed contact stress against physical measurements of contact stress made in cadaveric hips using Tekscan sensors. Four static loading tests in a variety of poses from heel-strike to toe-off were performed in two different cadaveric hip specimens with the acetabulum intact and again with an intentionally malreduced posterior wall acetabular fracture. DEA-computed contact stress was compared on a point-by-point basis to stress measured from the physical experiments. There was good agreement between computed and measured contact stress over the entire contact area (correlation coefficients ranged from 0.88 to 0.99). DEA-computed peak contact stress was within an average of 0.5 MPa (range 0.2-0.8 MPa) of the Tekscan peak stress for intact hips, and within an average of 0.6 MPa (range 0-1.6 MPa) for fractured cases. DEA-computed contact areas were within an average of 33% of the Tekscan-measured areas (range: 1.4-60%). These results indicate that the DEA methodology is a valid method for accurately estimating contact stress in both intact and fractured hips. Copyright © 2017 Elsevier Ltd. All rights reserved.

Control of welding residual stress for ensuring integrity against fatigue and stress-corrosion cracking

International Nuclear Information System (INIS)

Mochizuki, Masahito

2007-01-01

The availability of several techniques for residual stress control is discussed in this paper. The effectiveness of these techniques in protecting from fatigue and stress-corrosion cracking is verified by numerical analysis and actual experiment. In-process control during welding for residual stress reduction is easier to apply than using post-weld treatment. As an example, control of the welding pass sequence for multi-pass welding is applied to cruciform joints and butt-joints with an X-shaped groove. However, residual stress improvement is confirmed for post-weld processes. Water jet peening is useful for obtaining a compressive residual stress on the surface, and the tolerance against both fatigue and stress-corrosion cracking is verified. Because cladding with a corrosion-resistant material is also effective for preventing stress-corrosion cracking from a metallurgical perspective, the residual stress at the interface of the base metal is carefully considered. The residual stress of the base metal near the clad edge is confirmed to be within the tolerance of crack generation. Controlling methods both during and after welding processes are found to be effective for ensuring the integrity of welded components

Measurement of residual stress in textured Al alloy by neutron diffraction method

International Nuclear Information System (INIS)

Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

1999-01-01

Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

METHODS OF NOISE LEVEL REDUCTION OF DRIVE IN LATHES

Directory of Open Access Journals (Sweden)

Janusz ROGULA

2014-06-01

Full Text Available The aim of this work is method presentation to noise level reduction of fixed headstock of the lathe. It is connected with the causes finding of non-uniform work of lathe headstock, description of recent design and its analysis. Problem of the excessive noise level concern to near 35% of the lathes have been produced. In spite of lack of noise reduction possibility there were no system solution of problem. Design optimisation weren’t done after application the electric motor with inverter. New solution of electric motor control let to reduce number of gear wheels in lathe drive system. For this drive solution there weren’t made the analysis of drive particular parts influence on the noise generation.

Noise reduction methods for nucleic acid and macromolecule sequencing

Science.gov (United States)

Schuller, Ivan K.; Di Ventra, Massimiliano; Balatsky, Alexander

2018-05-08

Methods, systems, and devices are disclosed for processing macromolecule sequencing data with substantial noise reduction. In one aspect, a method for reducing noise in a sequential measurement of a macromolecule comprising serial subunits includes cross-correlating multiple measured signals of a physical property of subunits of interest of the macromolecule, the multiple measured signals including the time data associated with the measurement of the signal, to remove or at least reduce signal noise that is not in the same frequency and in phase with the systematic signal contribution of the measured signals.

A reduction method for phase equilibrium calculations with cubic equations of state

Directory of Open Access Journals (Sweden)

D. V. Nichita

2006-09-01

Full Text Available In this work we propose a new reduction method for phase equilibrium calculations using a general form of cubic equations of state (CEOS. The energy term in the CEOS is a quadratic form, which is diagonalized by applying a linear transformation. The number of the reduction parameters is related to the rank of the matrix C with elements (1-Cij, where Cij denotes the binary interaction parameters (BIPs. The dimensionality of the problem depends only on the number of reduction parameters, and is independent of the number of components in the mixture.

New computational and experimental stress analysis method for the design decision on optimum piston configuration. Piston oryoku no computer simulation to shinshikenho ni yoru keijo saitekika

Energy Technology Data Exchange (ETDEWEB)

Anno, N; Sugita, J [Honda R and D, Co. Ltd., Saitama (Japan)

1993-03-01

Piston troubles are mostly caused by cracks generating in each part of a piston. The finite element method (FEM) has been used for stress analysis of the piston, but has not been applied enough to design optimum configurations due to too much time for making models. In this study, stress analysis was carried out by the boundary element method (BEM), with which it is easy to make models and to change configurations, with various improvements. In addition, methods to execute a thermal load fatigue test and an actual running test to confirm analytical results were also improved. BEASY was used as basic software for analysis by BEM, and some improvements such as reduction of CPU time and optimization of memory using methods were carried out. It was easy to change configurations of the models by BEM, and the effect of the change in the piston boss configuration upon the stress agreed well with the actual test result. Design and evaluation of the optimum configuration has become easier by feedback of the results of the newly developed thermal load fatigue test to the analysis by BEM. 5 refs., 12 figs., 2 tabs.

Assessment methods for Bree-type ratcheting without the necessity of linearization of stresses and strains

International Nuclear Information System (INIS)

Fujioka, Terutaka

2015-01-01

This paper proposes methods for assessing Bree-type ratcheting in a cylinder subjected to constant internal pressure and cyclic thermal loading. The proposed methods are elastic analysis-route and elastic–plastic analysis-route. The former is based on the polynomial approximation of the elastic stress distributions for thermal stresses and the reference stress concept for estimating primary stress. The latter elastic–plastic route method is based on the concept of relative elastic core size. The methods proposed were validated by performing elastic–plastic finite element analyses of a smooth cylinder that exhibited Bree-type ratcheting. - Highlights: • Rationalization of the ratcheting assessment has been made. • The proposed methods include both elastic and elastic-plastic routes. • The elastic route method is based on skeletal point stress by elastic FEA. • The elastic-plastic route is based on elastic core size in elastic-plastic FEA. • These have been validated by elastic-plastic FEA causing Bree-type ratcheting

A novel cryogenic treatment for reduction of residual stresses in 2024 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Araghchi, M., E-mail: M.Araghchi@ma.iut.ac.ir [Department of Materials Engineering, Malek Ashtar University of Technology, Isfahan (Iran, Islamic Republic of); Mansouri, H.; Vafaei, R. [Department of Materials Engineering, Malek Ashtar University of Technology, Isfahan (Iran, Islamic Republic of); Guo, Yina [Bernal Institute, University of Limerick, Limerick (Ireland)

2017-03-24

Residual stresses induced during quenching of aluminum alloys cause distortion and have a negative effect on their properties. The purpose of this study is to reduce the residual stresses and improve mechanical properties by using a novel cryogenic treatment. Water quenched samples were cooled down by immersion in liquid nitrogen at −196 °C, following by rapid heating in hot oil at 180 °C and finally they were artificially aged. Residual stresses was measured by the hole drilling strain gauge method. The mechanical properties and microstructure of a heat treated samples were investigated by means of hardness measurements, tensile tests and transmission electron microscopy. The results showed that this treatment can relieve up to 71% of the residual stresses compared to 29% related to the traditional cryogenic treatment that used boiling water as the reheating medium. In addition, there is a considerable increase of about 75 MPa in the ultimate tensile strength in comparison to the T6 heat-treated alloy. TEM observations revealed that the S′ precipitates were fine and uniformly distributed in the microstructure due to deformation during reheating in hot oil.

Test with different stress measurement methods in two orthogonal bore holes in Aespoe HRL

Energy Technology Data Exchange (ETDEWEB)

Janson, Thomas; Stigsson, Martin [Golder Associates AB, Stockholm (Sweden)

2002-12-01

Within the scope of work, to provide the necessary rock mechanics support for the site investigations, SKB has studied some available pieces of equipment for in situ stress measurements in deep boreholes. A project with the objective to compare three different pieces of equipment for in situ stress measurements under similar conditions has been carried out. The main objective for the project is to compare the three different pieces of equipment for in situ stress measurements and find a strategy for SKB's Site Investigations to determine the state of stress in the rock mass. Two units of equipment use the overcoring method while the third uses the hydraulic fracturing method. The overcoring was performed by AECL, using Deep Door stopper Gauge System (DDGS), and SwedPower, using their triaxial strain measuring instrument (Borre Probe). MeSy Geo Systeme GmbH performed the hydraulic fracturing. The DDGS system is a new method to SKB while the experience of the SwedPower overcoring and the hydraulic fracturing methods are long. The tests were performed in the same orthogonal boreholes at Aespoe Hard Rock Laboratory (HRL), Oskarshamn, Sweden. The measured results have been verified against known conditions at the Aespoe HRL. The results from the three in situ stress measurement methods rose more questions than answers. Which illustrate the complexity to determine the in situ stresses in a rock mass. To understand the difference in results and answer the questions, it was necessary to do deeper investigations such as laboratory tests and theoretical calculations such as geological structure model, analysis of the influence of a nearby fracture, P-wave measurements, uniaxial tests on small cores from the HQ-3 core, theoretical and numerical analyses of the hole bottom (theoretical strains, stress concentrations and microcracking), auditing of DDGS measurements results and assumptions in the DDGS analyse and microscopy investigations on the cores. The following

Mindfulness-based stress reduction for veterans exposed to military sexual trauma: rationale and implementation considerations.

Science.gov (United States)

Gallegos, Autumn M; Cross, Wendi; Pigeon, Wilfred R

2015-06-01

Military sexual trauma (MST) represents a significant public health concern among military personnel and Veterans and is associated with considerable morbidity and suicide risk. It is estimated that 22% of Veteran women and 1% of Veteran men experienced sexual assault or repeated, threatening sexual harassment during their military service. Exposure to traumatic stress has detrimental effects on emotion regulation, which refers to a set of strategies used to modulate different components of emotion at different points on the trajectory of an emotional response. Mindfulness-based interventions offer approaches to health that focus on mind and body practices that can help regulate the experience and expression of difficult emotions. Mindfulness-based stress reduction (MBSR) is an evidence-based therapy shown to be effective for depression, anxiety, and post-traumatic stress disorder. This article discusses the rationale for providing MBSR to Veterans who have been exposed to MST. The article also discusses ways to facilitate implementation of this practice in the U.S. Department of Veterans Affairs health care system. We address potential barriers to care and ways to facilitate implementation at the patient, provider, organization/local, and policy levels. MBSR is likely to be an important component of a comprehensive approach to care for Veterans exposed to MST. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

Comparison of residual stress measurement in thin films using surface micromachining method

International Nuclear Information System (INIS)

He, Q.; Luo, Z.X.; Chen, X.Y.

2008-01-01

Conductive, dielectric, semiconducting, piezoelectric and ferroelectric thin films are extensively used for MEMS/NEMS applications. One of the important parameters of thin films is residual stress. The residual stress can seriously affect the properties, performance and long-term stability of the films. Excessive compressive or tensile stress results in buckling, cracking, splintering and sticking problems. Stress measurement techniques are therefore essential for both process development and process monitoring. Many suggestions for stress measurement in thin films have been made over the past several decades. This paper is concentrated on the in situ stress measurement using surface micromachining techniques to determine the residual stress. The authors review and compare several types of stress measurement methods including buckling technique, rotating technique, micro strain gauge and long-short beam strain sensor

Comparison of Efficacy of Eye Movement, Desensitization and Reprocessing and Cognitive Behavioral Therapy Therapeutic Methods for Reducing Anxiety and Depression of Iranian Combatant Afflicted by Post Traumatic Stress Disorder

Science.gov (United States)

Narimani, M.; Sadeghieh Ahari, S.; Rajabi, S.

This research aims to determine efficacy of two therapeutic methods and compare them; Eye Movement, Desensitization and Reprocessing (EMDR) and Cognitive Behavioral Therapy (CBT) for reduction of anxiety and depression of Iranian combatant afflicted with Post traumatic Stress Disorder (PTSD) after imposed war. Statistical population of current study includes combatants afflicted with PTSD that were hospitalized in Isar Hospital of Ardabil province or were inhabited in Ardabil. These persons were selected through simple random sampling and were randomly located in three groups. The method was extended test method and study design was multi-group test-retest. Used tools include hospital anxiety and depression scale. This survey showed that exercise of EMDR and CBT has caused significant reduction of anxiety and depression.

Modified Feddes type stress reduction function for modeling root water uptake: Accounting for limited aeration and low water potential

Science.gov (United States)

Peters, Andre; Durner, Wolfgang; Iden, Sascha C.

2017-04-01

Modeling water flow in the soil-plant-atmosphere continuum with the Richards equation requires a model for the sink term describing water uptake by plant roots. Despite recent progress in developing process-based models of water uptake by plant roots and water flow in aboveground parts of vegetation, effective models of root water uptake are widely applied and necessary for large-scale applications. Modeling root water uptake consists of three steps, (i) specification of the spatial distribution of potential uptake, (ii) reduction of uptake due to various stress sources, and (iii) enhancement of uptake in part of the simulation domain to describe compensation. We discuss the conceptual shortcomings of the frequently used root water uptake model of Feddes and suggest a simple but effective improvement of the model. The improved model parametrizes water stress in wet soil by a reduction scheme which is formulated as function of air content where water stress due to low soil water potential is described by the original approach of Feddes. The improved model is physically more consistent than Feddes' model because water uptake in wet soil is limited by aeration which is a function of water content. The suggested modification is particularly relevant for simulations in heterogeneous soils, because stress parameters are uniquely defined for the entire simulation domain, irrespective of soil texture. Numerical simulations of water flow and root water uptake in homogeneous and stochastic heterogeneous soils illustrate the effect of the new model on root water uptake and actual transpiration. For homogeneous fine-textured soils, root water uptake never achieves its potential rate. In stochastic heterogeneous soil, water uptake is more pronounced at the interfaces between fine and coarse regions which has potential implications for plant growth, nutrient uptake and depletion.

Application of advanced data reduction methods to gas turbine dynamic analysis

International Nuclear Information System (INIS)

Juhl, P.B.

1978-01-01

This paper discusses the application of advanced data reduction methods to the evaluation of dynamic data from gas turbines and turbine components. The use of the Fast Fourier Transform and of real-time spectrum analyzers is discussed. The use of power spectral density and probability density functions for analyzing random data is discussed. Examples of the application of these modern techniques to gas turbine testing are presented. The use of the computer to automate the data reduction procedures is discussed. (orig.) [de

Method of reduction of nitroaromatics by enzymatic reaction with redox enzymes

Science.gov (United States)

Shah, Manish M.

2000-01-01

A method for the controlled reduction of nitroaromatic compounds such as nitrobenzene and 2,4,6-trinitrotoluene by enzymatic reaction with redox enzymes, such as Oxyrase (Trademark of Oxyrase, Inc., Mansfield, Ohio).

Strength Reduction of Coal Pillar after CO2 Sequestration in Abandoned Coal Mines

Directory of Open Access Journals (Sweden)

Qiuhao Du

2017-02-01

Full Text Available CO2 geosequestration is currently considered to be the most effective and economical method to dispose of artificial greenhouse gases. There are a large number of coal mines that will be scrapped, and some of them are located in deep formations in China. CO2 storage in abandoned coal mines will be a potential option for greenhouse gas disposal. However, CO2 trapping in deep coal pillars would induce swelling effects of coal matrix. Adsorption-induced swelling not only modifies the volume and permeability of coal mass, but also causes the basic physical and mechanical properties changing, such as elastic modulus and Poisson ratio. It eventually results in some reduction in pillar strength. Based on the fractional swelling as a function of time and different loading pressure steps, the relationship between volumetric stress and adsorption pressure increment is acquired. Eventually, this paper presents a theory model to analyze the pillar strength reduction after CO2 adsorption. The model provides a method to quantitatively describe the interrelation of volumetric strain, swelling stress, and mechanical strength reduction after gas adsorption under the condition of step-by-step pressure loading and the non-Langmuir isothermal model. The model might have a significantly important implication for predicting the swelling stress and mechanical behaviors of coal pillars during CO2 sequestration in abandoned coal mines.

New Cogging Torque Reduction Methods for Permanent Magnet Machine

Science.gov (United States)

Bahrim, F. S.; Sulaiman, E.; Kumar, R.; Jusoh, L. I.

2017-08-01

Permanent magnet type motors (PMs) especially permanent magnet synchronous motor (PMSM) are expanding its limbs in industrial application system and widely used in various applications. The key features of this machine include high power and torque density, extending speed range, high efficiency, better dynamic performance and good flux-weakening capability. Nevertheless, high in cogging torque, which may cause noise and vibration, is one of the threat of the machine performance. Therefore, with the aid of 3-D finite element analysis (FEA) and simulation using JMAG Designer, this paper proposed new method for cogging torque reduction. Based on the simulation, methods of combining the skewing with radial pole pairing method and skewing with axial pole pairing method reduces the cogging torque effect up to 71.86% and 65.69% simultaneously.

Two-step method to evaluate equibiaxial residual stress of metal surface based on micro-indentation tests

International Nuclear Information System (INIS)

Nishikawa, Masaaki; Soyama, Hitoshi

2011-01-01

Highlights: → The sensitivity to residual stress was improved by selecting the depth parameter. → Residual stress could be obtained while determining the effect of unknown parameters. → The estimated residual stress agreed well with those of X-ray diffraction. -- Abstract: The present study proposed a method to evaluate the equibiaxial compressive residual stress of a metal surface by means of a depth-sensing indentation method using a spherical indenter. Inverse analysis using the elastic-plastic finite-element model for an indentation test was established to evaluate residual stress from the indentation load-depth curve. The proposed inverse analysis utilizes two indentation test results for a reference specimen whose residual stress is already known and for a target specimen whose residual stress is unknown, in order to exclude the effect of other unknown mechanical properties, such as Young's modulus and yield stress. Residual stress estimated by using the indentation method is almost identical to that measured by X-ray diffraction for indentation loads of 0.49-0.98 N. Therefore, it can be concluded that the proposed method can effectively evaluate residual stress on metal surface.

Mindfulness-based stress reduction added to care as usual for lung cancer patients and/or their partners: A multicentre randomized controlled trial

NARCIS (Netherlands)

Schellekens, M.P.J.; Hurk, D.G.M. van den; Prins, J.B.; Donders, A.R.T.; Molema, J.; Dekhuijzen, R.; Drift, M.A. van der; Speckens, A.E.M.

2017-01-01

OBJECTIVE: Lung cancer patients report among the highest distress rates of all cancer patients. Partners report similar distress rates. The present study examined the effectiveness of additional mindfulness-based stress reduction (care as usual [CAU] + MBSR) versus solely CAU to reduce psychological

Stress reduction through music in patients undergoing cerebral angiography

Energy Technology Data Exchange (ETDEWEB)

Schneider, N.; Becker, H. [Dept. of Neuroradiology, Hannover Medical School (Germany); Schedlowski, M. [Dept. of Clinical Psychiatry and Psychotherapy, Hannover Medical School (Germany); Schuermeyer, T.H. [Dept. of Endocrinology, Hannover Medical School (Germany)

2001-06-01

We studied the influence of music on stress reaction of patients during cerebral angiography. We randomised 30 patients to a music or a control group. We measured stress hormones, blood pressure, heart rate and psychological parameters. Patients examined without music showed rising levels of cortisol in plasma, indicating high stress levels, while cortisol in patients examined with music remained stable. Systolic blood pressure was significantly lower listening to music. Patients with a high level of fear did appear to benefit particularly from the music. (orig.)

Stress reduction through music in patients undergoing cerebral angiography

International Nuclear Information System (INIS)

Schneider, N.; Becker, H.; Schedlowski, M.; Schuermeyer, T.H.

2001-01-01

We studied the influence of music on stress reaction of patients during cerebral angiography. We randomised 30 patients to a music or a control group. We measured stress hormones, blood pressure, heart rate and psychological parameters. Patients examined without music showed rising levels of cortisol in plasma, indicating high stress levels, while cortisol in patients examined with music remained stable. Systolic blood pressure was significantly lower listening to music. Patients with a high level of fear did appear to benefit particularly from the music. (orig.)

Method for simulating dose reduction in digital mammography using the Anscombe transformation

Energy Technology Data Exchange (ETDEWEB)

Borges, Lucas R., E-mail: lucas.rodrigues.borges@usp.br; Oliveira, Helder C. R. de; Nunes, Polyana F.; Vieira, Marcelo A. C. [Department of Electrical and Computer Engineering, São Carlos School of Engineering, University of São Paulo, 400 Trabalhador São-Carlense Avenue, São Carlos 13566-590 (Brazil); Bakic, Predrag R.; Maidment, Andrew D. A. [Department of Radiology, Hospital of the University of Pennsylvania, University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104 (United States)

2016-06-15

Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. Results: The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. Conclusions: A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe

Method for simulating dose reduction in digital mammography using the Anscombe transformation

International Nuclear Information System (INIS)

Borges, Lucas R.; Oliveira, Helder C. R. de; Nunes, Polyana F.; Vieira, Marcelo A. C.; Bakic, Predrag R.; Maidment, Andrew D. A.

2016-01-01

Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. Results: The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. Conclusions: A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe

Development, implementation, and evaluation of a mental rehearsal strategy to improve clinical performance and reduce stress: A mixed methods study.

Science.gov (United States)

Ignacio, Jeanette; Dolmans, Diana; Scherpbier, Albert; Rethans, Jan-Joost; Lopez, Violeta; Liaw, Sok Ying

2016-02-01

Mental rehearsal is a form of mental training that has been used by physicians and nurses to improve performance of clinical skills, and as a vital component of stress management training. To help novice nurses deal with often stressful clinical events that require the processing of information essential to patient management, a mental rehearsal strategy was developed and implemented in a Year 3 nursing simulation program. Inherent to mental rehearsal is imagery, which facilitates cognitive and affective modification, and reduction of extraneous cognitive load. As such, it was expected that the mental rehearsal strategy would improve students' performance and reduce stress in managing deteriorating patients. The study used a mixed methods design. Eighteen Year 3 nursing students participated in the pre- and post-design study, which consisted of the development and implementation of a mental rehearsal strategy. The Rescuing A Patient In Deteriorating Situations (RAPIDS) tool was used to assess performance. Heart rates and systolic blood pressures were used to measure stress. The State-Trait Anxiety Inventory (STAI) was used as a psychological measure of stress/anxiety. Five participants were involved in a focus group discussion that evaluated the usefulness of the mental rehearsal strategy. There was a significant improvement in performance (Pstrategy. The mental rehearsal strategy for deteriorating patient management can be valuable based on the findings on performance and based on the participants' feedback. Its role in reducing stress, however, needs further evaluation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Residual stresses measurement by using ring-core method and 3D digital image correlation technique

International Nuclear Information System (INIS)

Hu, Zhenxing; Xie, Huimin; Zhu, Jianguo; Wang, Huaixi; Lu, Jian

2013-01-01

Ring-core method/three-dimensional digital image correlation (3D DIC) residual stresses measurement is proposed. Ring-core cutting is a mechanical stress relief method, and combining with 3D DIC system the deformation of the specimen surface can be measured. An optimization iteration method is proposed to obtain the residual stress and rigid-body motion. The method has the ability to cut an annular trench at a different location out of the field of view. A compression test is carried out to demonstrate how residual stress is determined by using 3D DIC system and outfield measurement. The results determined by the approach are in good agreement with the theoretical value. Ring-core/3D DIC has shown its robustness to determine residual stress and can be extended to application in the engineering field. (paper)

A study on the evaluation of vibration effect and the development of vibration reduction method for Wolsung unit 1 main steam piping

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyun; Kim, Yeon Whan [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Tae Ryong; Park, Jin Ho [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of)

1996-08-01

The main steam piping of nuclear power plant which runs between steam generator and high pressure turbine has been experienced to have a severe effect on the safe operation of the plant due to the vibration induced by the steam flowing inside the piping. The imposed cyclic loads by the vibration could result in the degradation of the related structures such as connection parts between main instruments, valves, pipe supports and building. The objective of the study is to reduce the vibration level of Wolsung nuclear power plant unit 1 main steam pipeline by analyzing vibration characteristics of the piping, identifying sources of the vibration and developing a vibration reduction method .The location of the maximum vibration is piping between the main steam header and steam chest .The stress level was found to be within the allowable limit .The main vibration frequency was found to be 4{approx}6 Hz which is the same as the natural frequency from model test .A vibration reduction method using pipe supports of energy absorbing type(WEAR)is selected .The measured vibration level after WEAR installation was reduced about 36{approx}77% in displacement unit (author). 36 refs., 188 figs.

Applied methods for mitigation of damage by stress corrosion in BWR type reactors; Metodos aplicados para la mitigacion del dano por corrosion bajo esfuerzo en reactores BWR

Energy Technology Data Exchange (ETDEWEB)

Hernandez C, R.; Diaz S, A.; Gachuz M, M.; Arganis J, C. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencia de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1998-07-01

The Boiling Water nuclear Reactors (BWR) have presented stress corrosion problems, mainly in components and pipes of the primary system, provoking negative impacts in the performance of energy generator plants, as well as the increasing in the radiation exposure to personnel involucred. This problem has caused development of research programs, which are guided to find solution alternatives for the phenomena control. Among results of greater relevance the control for the reactor water chemistry stands out particularly in the impurities concentration and oxidation of radiolysis products; as well as the supervision in the materials selection and the stresses levels reduction. The present work presents the methods which can be applied to diminish the problems of stress corrosion in BWR reactors. (Author)

Iterative methods for dose reduction and image enhancement in tomography

Science.gov (United States)

Miao, Jianwei; Fahimian, Benjamin Pooya

2012-09-18

A system and method for creating a three dimensional cross sectional image of an object by the reconstruction of its projections that have been iteratively refined through modification in object space and Fourier space is disclosed. The invention provides systems and methods for use with any tomographic imaging system that reconstructs an object from its projections. In one embodiment, the invention presents a method to eliminate interpolations present in conventional tomography. The method has been experimentally shown to provide higher resolution and improved image quality parameters over existing approaches. A primary benefit of the method is radiation dose reduction since the invention can produce an image of a desired quality with a fewer number projections than seen with conventional methods.

Laser reflection method for determination of shear stress in low density transitional flows

Science.gov (United States)

Sathian, Sarith P.; Kurian, Job

2006-03-01

The details of laser reflection method (LRM) for the determination of shear stress in low density transitional flows are presented. The method is employed to determine the shear stress due to impingement of a low density supersonic free jet issuing out from a convergent divergent nozzle on a flat plate. The plate is smeared with a thin oil film and kept parallel to the nozzle axis. For a thin oil film moving under the action of aerodynamic boundary layer, the shear stress at the air-oil interface is equal to the shear stress between the surface and air. A direct and dynamic measurement of the oil film slope generated by the shear force is done using a position sensing detector (PSD). The thinning rate of the oil film is directly measured which is the major advantage of the LRM. From the oil film slope history, calculation of the shear stress is done using a three-point formula. The range of Knudsen numbers investigated is from 0.028 to 0.516. Pressure ratio across the nozzle varied from 3,500 to 8,500 giving highly under expanded free jets. The measured values of shear, in the overlapping region of experimental parameters, show fair agreement with those obtained by force balance method and laser interferometric method.

Analytical method for thermal stress analysis of plasma facing materials

Science.gov (United States)

You, J. H.; Bolt, H.

2001-10-01

The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed.

Analytical method for thermal stress analysis of plasma facing materials

International Nuclear Information System (INIS)

You, J.H.; Bolt, H.

2001-01-01

The thermo-mechanical response of plasma facing materials (PFMs) to heat loads from the fusion plasma is one of the crucial issues in fusion technology. In this work, a fully analytical description of the thermal stress distribution in armour tiles of plasma facing components is presented which is expected to occur under typical high heat flux (HHF) loads. The method of stress superposition is applied considering the temperature gradient and thermal expansion mismatch. Several combinations of PFMs and heat sink metals are analysed and compared. In the framework of the present theoretical model, plastic flow and the effect of residual stress can be quantitatively assessed. Possible failure features are discussed

Therapeutic touch and post-Hurricane Hugo stress.

Science.gov (United States)

Olson, M; Sneed, N; Bonadonna, R; Ratliff, J; Dias, J

1992-06-01

This repeated-session design sought to answer questions about the effectiveness of therapeutic touch in reduction of stress for 23 individuals following a natural disaster. In addition, methodological issues related to the average length of time for a therapeutic-touch treatment and a method of documenting the nonverbal interaction between subject and toucher were investigated. Findings indicate that stressed people report themselves to be less stressed following therapeutic touch (p = .05). Time of therapeutic-touch intervention varied significantly between the touchers, with a range of 6.8 to 20 minutes. Qualitative data examining the interaction of toucher and subject raised a number of questions that require further study.

Stress strain modelling of casting processes in the framework of the control volume method

DEFF Research Database (Denmark)

Hattel, Jesper; Andersen, Søren; Thorborg, Jesper

1998-01-01

Realistic computer simulations of casting processes call for the solution of both thermal, fluid-flow and stress/strain related problems. The multitude of the influencing parameters, and their non-linear, transient and temperature dependent nature, make the calculations complex. Therefore the nee......, the present model is based on the mainly decoupled representation of the thermal, mechanical and microstructural processes. Examples of industrial applications, such as predicting residual deformations in castings and stress levels in die casting dies, are presented...... for fast, flexible, multidimensional numerical methods is obvious. The basis of the deformation and stress/strain calculation is a transient heat transfer analysis including solidification. This paper presents an approach where the stress/strain and the heat transfer analysis uses the same computational...... domain, which is highly convenient. The basis of the method is the control volume finite difference approach on structured meshes. The basic assumptions of the method are shortly reviewed and discussed. As for other methods which aim at application oriented analysis of casting deformations and stresses...

A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

Science.gov (United States)

Asgari, B; Osman, S A; Adnan, A

2014-01-01

Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

B. Asgari

2014-01-01

Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

A Method Using Optical Contactless Displacement Sensors to Measure Vibration Stress of Small-Bore Piping.

Science.gov (United States)

Maekawa, Akira; Tsuji, Takashi; Takahashi, Tsuneo; Noda, Michiyasu

2014-02-01

In nuclear power plants, vibration stress of piping is frequently evaluated to prevent fatigue failure. A simple and fast measurement method is attractive to evaluate many piping systems efficiently. In this study, a method to measure the vibration stress using optical contactless displacement sensors was proposed, the prototype instrument was developed, and the instrument practicality for the method was verified. In the proposed method, light emitting diodes (LEDs) were used as measurement sensors and the vibration stress was estimated by measuring the deformation geometry of the piping caused by oscillation, which was measured as the piping curvature radius. The method provided fast and simple vibration estimates for small-bore piping. Its verification and practicality were confirmed by vibration tests using a test pipe and mock-up piping. The stress measured by both the proposed method and an accurate conventional method using strain gauges were in agreement, and it was concluded that the proposed method could be used for actual plant piping systems.

Accelerated creep in solid oxide fuel cell anode supports during reduction

DEFF Research Database (Denmark)

Frandsen, Henrik Lund; Makowska, Malgorzata Grazyna; Greco, Fabio

2016-01-01

To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been...... studied previously. In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two...... measurements could be explained by newly observed stress promoted reduction. Finally, samples exposed to a small tensile stress (∼ 0.004 MPa) were observed to expand during reduction, which is in contradiction to previous literature. These observations suggest that release of internal residual stresses between...

Selective hydrogenation of phenol to cyclohexanone over Pd@CN (N-doped porous carbon): Role of catalyst reduction method

Science.gov (United States)

Hu, Shuo; Yang, Guangxin; Jiang, Hong; Liu, Yefei; Chen, Rizhi

2018-03-01

Selective phenol hydrogenation is a green and sustainable technology to produce cyclohexanone. The work focused on investigating the role of catalyst reduction method in the liquid-phase phenol hydrogenation to cyclohexanone over Pd@CN (N-doped porous carbon). A series of reduction methods including flowing hydrogen reduction, in-situ reaction reduction and liquid-phase reduction were designed and performed. The results highlighted that the reduction method significantly affected the catalytic performance of Pd@CN in the liquid-phase hydrogenation of phenol to cyclohexanone, and the liquid-phase reduction with the addition of appropriate amount of phenol was highly efficient to improve the catalytic activity of Pd@CN. The influence mechanism was explored by a series of characterizations. The results of TEM, XPS and CO chemisorption confirmed that the reduction method mainly affected the size, surface composition and dispersion of Pd in the CN material. The addition of phenol during the liquid-phase reduction could inhibit the aggregation of Pd NPs and promote the reduction of Pd (2+), and then improved the catalytic activity of Pd@CN. The work would aid the development of high-performance Pd@CN catalysts for selective phenol hydrogenation.

Theoretical methods for creep and stress relaxation studies of SSC coil

International Nuclear Information System (INIS)

McAdams, J.; Markley, F.

1992-04-01

Extrapolation of laboratory measurements of SSC coil properties to the actual construction of SSC magnets requires mathematical models of the experimental data. A variety of models were used to approximate the data collected from creep and stress relaxation experiments performed on Kapton film and SSC coil samples. The coefficients for these mathematical models were found by performing a least-squares fit via the program MINUIT. Once the semiempirical expressions for the creep data were found, they were converted to expressions for stress relaxation using an approximate I pn of the Laplace integral relating the two processes. The data sets from creep experiments were also converted directly to stress relaxation data by numeric integration. Both of these methods allow comparison of data from two different methods of measuring viscoelastic properties. Three companion papers presented at this conference will present: Stress relaxation in SSC 50mm dipole coil. Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures. Temperature dependence of the viscoelastic properties of SSC coil insulation (Kapton)

Numerical comparison of robustness of some reduction methods in rough grids

KAUST Repository

Hou, Jiangyong

2014-04-09

In this article, we present three nonsymmetric mixed hybrid RT 1 2 methods and compare with some recently developed reduction methods which are suitable for the single-phase Darcy flow problem with full anisotropic and highly heterogeneous permeability on general quadrilateral grids. The methods reviewed are multipoint flux approximation (MPFA), multipoint flux mixed finite element method, mixed-finite element with broken RT 1 2 method, MPFA-type mimetic finite difference method, and symmetric mixed-hybrid finite element method. The numerical experiments of these methods on different distorted meshes are compared, as well as their differences in performance of fluxes are discussed. © 2014 Wiley Periodicals, Inc.

Effect of Mindfulness Based Stress Reduction (MBSR in Increasing Pain Tolerance and Improving the Mental Health of Injured Athletes

Directory of Open Access Journals (Sweden)

Warhel Asim Mohammed

2018-05-01

Full Text Available Literature indicates that injured athletes face both physical and psychological distress after they have been injured. In this study, a Mindfulness Based Stress Reduction (MBSR was utilised as an intervention for use during the period of recovery with injured athletes and, to the best of our knowledge, this is the first study using MBSR as an intervention for this purpose.Objective: The aim of this research was to investigate the role of MBSR practise in reducing the perception of pain and decreasing anxiety/stress, as well as increasing pain tolerance and mindfulness. An additional aim was to increase positive mood and decrease negative mood in injured athletes.Methods: The participants comprised of twenty athletes (male = 14; female = 6; age range = 21–36 years who had severe injuries, preventing their participation in sport for more than 3 months. Prior to their injury, the participants had trained regularly with their University teams and participated in official university championships. Both groups followed their normal physiotherapy treatment, but in addition, the intervention group practised mindfulness meditation for 8 weeks (one 90-min session/week. A Cold Pressor Test (CPT was used to assess pain tolerance. In contrast, the perception of pain was measured using a Visual Analogue Scale. Other measurements used were the Mindful Attention Awareness Scale (MAAS, Depression Anxiety and Stress Scale (DASS, and Profile of Mood States (POMS.Results: Our results demonstrated an increase in pain tolerance for the intervention group and an increase in mindful awareness for injured athletes. Moreover, our findings observed a promising change in positive mood for both groups. Regarding the Stress/Anxiety scores, our findings showed a notable decrease across sessions; however, no significant changes were observed in other main and interaction effects in both groups.Conclusion: Injured athletes can benefit from using mindfulness as part of the

Application of x-ray method for measuring internal stress in the gear teeth surface layer

International Nuclear Information System (INIS)

Zaborowski, T.

1996-01-01

This paper presents the methodics of the internal stress measurements concerning cylindrical gear teeth of involute profile. There are the method selected, relation between stress and strain presented and conditions of investigation discussed in the study, including preparation of samples for investigation and conditions of the strain measurement. Exemplifying results of stress measurements for teeth of gears made of 4OH steel are shown. Suitability of the developed investigation method is indicated

Understanding Student Stress and Coping in Elementary School: A Mixed-Method, Longitudinal Study

Science.gov (United States)

Sotardi, Valerie A.

2016-01-01

This mixed-method, longitudinal study examined daily school stress and coping strategies of elementary schoolchildren in the United States. Students (n = 65) between the ages of 7 and 11 years reported daily school stress measures for 8 weeks and completed individual stress and coping interviews. Results highlight critical relations between…

A Pilot Study of the Effects of Mindfulness-Based Stress Reduction on Post-traumatic Stress Disorder Symptoms and Brain Response to Traumatic Reminders of Combat in Operation Enduring Freedom/Operation Iraqi Freedom Combat Veterans with Post-traumatic Stress Disorder

Directory of Open Access Journals (Sweden)

James Douglas Bremner

2017-08-01

Full Text Available ObjectiveBrain imaging studies in patients with post-traumatic stress disorder (PTSD have implicated a circuitry of brain regions including the medial prefrontal cortex, amygdala, hippocampus, parietal cortex, and insula. Pharmacological treatment studies have shown a reversal of medial prefrontal deficits in response to traumatic reminders. Mindfulness-based stress reduction (MBSR is a promising non-pharmacologic approach to the treatment of anxiety and pain disorders. The purpose of this study was to assess the effects of MBSR on PTSD symptoms and brain response to traumatic reminders measured with positron-emission tomography (PET in Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF combat veterans with PTSD. We hypothesized that MBSR would show increased prefrontal response to stress and improved PTSD symptoms in veterans with PTSD.MethodTwenty-six OEF/OIF combat veterans with PTSD who had recently returned from a combat zone were block randomized to receive eight sessions of MBSR or present-centered group therapy (PCGT. PTSD patients underwent assessment of PTSD symptoms with the Clinician-Administered PTSD Scale (CAPS, mindfulness with the Five Factor Mindfulness Questionnaire (FFMQ and brain imaging using PET in conjunction with exposure to neutral and Iraq combat-related slides and sound before and after treatment. Nine patients in the MBSR group and 8 in the PCGT group completed all study procedures.ResultsPost-traumatic stress disorder patients treated with MBSR (but not PCGT had an improvement in PTSD symptoms measured with the CAPS that persisted for 6 months after treatment. MBSR also resulted in an increase in mindfulness measured with the FFMQ. MBSR-treated patients had increased anterior cingulate and inferior parietal lobule and decreased insula and precuneus function in response to traumatic reminders compared to the PCGT group.ConclusionThis study shows that MBSR is a safe and effective treatment for PTSD

Analysis of a plane stress wave by the moving least squares method

Directory of Open Access Journals (Sweden)

Wojciech Dornowski

2014-08-01

Full Text Available A meshless method based on the moving least squares approximation is applied to stress wave propagation analysis. Two kinds of node meshes, the randomly generated mesh and the regular mesh are used. The nearest neighbours’ problem is developed from a triangulation that satisfies minimum edges length conditions. It is found that this method of neighbours’ choice significantly improves the solution accuracy. The reflection of stress waves from the free edge is modelled using fictitious nodes (outside the plate. The comparison with the finite difference results also demonstrated the accuracy of the proposed approach.[b]Keywords[/b]: civil engineering, meshless method, moving least squares method, elastic waves

Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

Science.gov (United States)

Chamine, Irina; Oken, Barry S.

2015-01-01

Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG) task performance and event related potentials (ERP) components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo) and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime). GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention. PMID:25802539

Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

Directory of Open Access Journals (Sweden)

Irina Chamine

2015-01-01

Full Text Available Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG task performance and event related potentials (ERP components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime. GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention.

Enhancement of wind stress evaluation method under storm conditions

Science.gov (United States)

Chen, Yingjian; Yu, Xiping

2016-12-01

Wind stress is an important driving force for many meteorological and oceanographical processes. However, most of the existing methods for evaluation of the wind stress, including various bulk formulas in terms of the wind speed at a given height and formulas relating the roughness height of the sea surface with wind conditions, predict an ever-increasing tendency of the wind stress coefficient as the wind speed increases, which is inconsistent with the field observations under storm conditions. The wave boundary layer model, which is based on the momentum and energy conservation, has the advantage to take into account the physical details of the air-sea interaction process, but is still invalid under storm conditions without a modification. By including the energy dissipation due to the presence of sea spray, which is speculated to be an important aspect of the air-sea interaction under storm conditions, the wave boundary layer model is improved in this study. The improved model is employed to estimate the wind stress caused by an idealized tropical cyclone motion. The computational results show that the wind stress coefficient reaches its maximal value at a wind speed of about 40 m/s and decreases as the wind speed further increases. This is in fairly good agreement with the field data.

Estimation of In Situ Stresses with Hydro-Fracturing Tests and a Statistical Method

Science.gov (United States)

Lee, Hikweon; Ong, See Hong

2018-03-01

At great depths, where borehole-based field stress measurements such as hydraulic fracturing are challenging due to difficult downhole conditions or prohibitive costs, in situ stresses can be indirectly estimated using wellbore failures such as borehole breakouts and/or drilling-induced tensile failures detected by an image log. As part of such efforts, a statistical method has been developed in which borehole breakouts detected on an image log are used for this purpose (Song et al. in Proceedings on the 7th international symposium on in situ rock stress, 2016; Song and Chang in J Geophys Res Solid Earth 122:4033-4052, 2017). The method employs a grid-searching algorithm in which the least and maximum horizontal principal stresses ( S h and S H) are varied, and the corresponding simulated depth-related breakout width distribution as a function of the breakout angle ( θ B = 90° - half of breakout width) is compared to that observed along the borehole to determine a set of S h and S H having the lowest misfit between them. An important advantage of the method is that S h and S H can be estimated simultaneously in vertical wells. To validate the statistical approach, the method is applied to a vertical hole where a set of field hydraulic fracturing tests have been carried out. The stress estimations using the proposed method were found to be in good agreement with the results interpreted from the hydraulic fracturing test measurements.

Determining the Threshold Value of Basil Yield Reduction and Evaluation of Water Uptake Models under Salinity Stress Condition

OpenAIRE

M. Sarai Tabrizi; H. Babazadeh; M. Homaee; F. Kaveh Kaveh; M. Parsinejad

2016-01-01

Introduction: Several mathematical models are being used for assessing the plant response to the salinity of the root zone. The salinity of the soil and water resources is a major challenge for agricultural sector in Iran. Several mathematical models have been developed for plant responses to the salinity stress. However, these models are often applicable in particular conditions. The objectives of this study were to evaluate the threshold value of Basil yield reduction, modeling Basil respon...

Generalized stress field in granular soils heap with Rayleigh–Ritz method

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Gang Bi

2017-02-01

Full Text Available The stress field in granular soils heap (including piled coal will have a non-negligible impact on the settlement of the underlying soils. It is usually obtained by measurements and numerical simulations. Because the former method is not reliable as pressure cells instrumented on the interface between piled coal and the underlying soft soil do not work well, results from numerical methods alone are necessary to be doubly checked with one more method before they are extended to more complex cases. The generalized stress field in granular soils heap is analyzed with Rayleigh–Ritz method. The problem is divided into two cases: case A without horizontal constraint on the base and case B with horizontal constraint on the base. In both cases, the displacement functions u(x, y and v(x, y are assumed to be cubic polynomials with 12 undetermined parameters, which will satisfy the Cauchy's partial differential equations, generalized Hooke's law and boundary equations. A function is built with the Rayleigh–Ritz method according to the principle of minimum potential energy, and the problem is converted into solving two undetermined parameters through the variation of the function, while the other parameters are expressed in terms of these two parameters. By comparison of results from the Rayleigh–Ritz method and numerical simulations, it is demonstrated that the Rayleigh–Ritz method is feasible to study the generalized stress field in granular soils heap. Solutions from numerical methods are verified before being extended to more complicated cases.

Slot technique - an alternative method of scatter reduction in radiography

International Nuclear Information System (INIS)

Panzer, W.; Widenmann, L.

1983-01-01

The most common method of scatter reduction in radiography is the use of an antiscatter grid. Its disadvantage is the absorption of a certain percentage of primary radiation in the lead strips of the grid and the fact that due to the limited thickness of the lead strips their scatter absorption is also limited. A possibility for avoiding this disadvantage is offered by the so-called slot technique, ie, the successive exposure of the subject with a narrow fan beam provided by slots in rather thick lead plates. The results of a comparison between grid and slot technique regarding dose to the patient, scatter reduction, image quality and the effect of automatic exposure control are reported. (author)

Engine-propeller power plant aircraft community noise reduction key methods

Science.gov (United States)

Moshkov P., A.; Samokhin V., F.; Yakovlev A., A.

2018-04-01

Basic methods of aircraft-type flying vehicle engine-propeller power plant noise reduction were considered including single different-structure-and-arrangement propellers and piston engines. On the basis of a semiempirical model the expressions for blade diameter and number effect evaluation upon propeller noise tone components under thrust constancy condition were proposed. Acoustic tests performed at Moscow Aviation institute airfield on the whole qualitatively proved the obtained ratios. As an example of noise and detectability reduction provision a design-and-experimental estimation of propeller diameter effect upon unmanned aircraft audibility boundaries was performed. Future investigation ways were stated to solve a low-noise power plant design problem for light aircraft and unmanned aerial vehicles.

Reductive Stress in Inflammation-Associated Diseases and the Pro-Oxidant Effect of Antioxidant Agents

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Israel Pérez-Torres

2017-10-01

Full Text Available Abstract: Reductive stress (RS is the counterpart oxidative stress (OS, and can occur in response to conditions that shift the redox balance of important biological redox couples, such as the NAD+/NADH, NADP+/NADPH, and GSH/GSSG, to a more reducing state. Overexpression of antioxidant enzymatic systems leads to excess reducing equivalents that can deplete reactive oxidative species, driving the cells to RS. A feedback regulation is established in which chronic RS induces OS, which in turn, stimulates again RS. Excess reducing equivalents may regulate cellular signaling pathways, modify transcriptional activity, induce alterations in the formation of disulfide bonds in proteins, reduce mitochondrial function, decrease cellular metabolism, and thus, contribute to the development of some diseases in which NF-κB, a redox-sensitive transcription factor, participates. Here, we described the diseases in which an inflammatory condition is associated to RS, and where delayed folding, disordered transport, failed oxidation, and aggregation are found. Some of these diseases are aggregation protein cardiomyopathy, hypertrophic cardiomyopathy, muscular dystrophy, pulmonary hypertension, rheumatoid arthritis, Alzheimer’s disease, and metabolic syndrome, among others. Moreover, chronic consumption of antioxidant supplements, such as vitamins and/or flavonoids, may have pro-oxidant effects that may alter the redox cellular equilibrium and contribute to RS, even diminishing life expectancy.

Reductions in Circulating Endocannabinoid Levels in Individuals with Post-Traumatic Stress Disorder Following Exposure to the World Trade Center Attacks

Science.gov (United States)

Hill, Matthew N.; Bierer, Linda M.; Makotkine, Iouri; Golier, Julia A.; Galea, Sandro; McEwen, Bruce S.; Hillard, Cecilia J.; Yehuda, Rachel

2013-01-01

Endocannabinoid (eCB) signaling has been identified as a modulator of adaptation to stress, and is integral to basal and stress-induced glucocorticoid regulation. Furthermore, interactions between eCBs and glucocorticoids have been shown to be necessary for the regulation of emotional memories, suggesting that eCB function may relate to the development of post-traumatic stress disorder (PTSD). To examine this, plasma eCBs were measured in a sample (n=46) drawn from a population-based cohort selected for physical proximity to the World Trade Center (WTC) at the time of the 9/11 attacks. Participants received a structured diagnostic interview and were grouped according to whether they met diagnostic criteria for PTSD (no PTSD, n=22; lifetime diagnosis of PTSD = 24). eCB content (2-arachidonoylglycerol (2-AG) and anandamide (AEA)) and cortisol were measured from 8 a.m. plasma samples. Circulating 2-AG content was significantly reduced among individuals meeting diagnostic criteria for PTSD. The effect of reduced 2-AG content in PTSD remained significant after controlling for the stress of exposure to the WTC collapse, gender, depression and alcohol abuse. There were no significant group differences for AEA or cortisol levels; however, across the whole sample AEA levels positively correlated with circulating cortisol, and AEA levels exhibited a negative relationship with the degree of intrusive symptoms within the PTSD sample. This report shows that PTSD is associated with a reduction in circulating levels of the eCB 2-AG. Given the role of 2-AG in the regulation of the stress response, these data support the hypothesis that deficient eCB signaling may be a component of the glucocorticoid dysregulation associated with PTSD. The negative association between AEA levels and intrusive symptoms is consistent with animal data indicating that reductions in AEA promote retention of aversive emotional memories. Future work will aim to replicate these findings and extend their

Method for simulating dose reduction in digital mammography using the Anscombe transformation.

Science.gov (United States)

Borges, Lucas R; Oliveira, Helder C R de; Nunes, Polyana F; Bakic, Predrag R; Maidment, Andrew D A; Vieira, Marcelo A C

2016-06-01

This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe transformation. NNPS, PS, and local noise

Guided Imagery and Stress in Pregnant Adolescents.

Science.gov (United States)

Flynn, Theresa A; Jones, Brittney A; Ausderau, Karla K

2016-01-01

We examined the effects of a guided imagery intervention on perceived stress in pregnant adolescents. Thirty-five pregnant adolescents recruited from a local alternative education program participated in a guided imagery intervention. Participants listened to a pregnancy-specific guided imagery recording on four separate occasions during their pregnancies. Perceived stress was measured immediately before and after each session using the Perceived Stress Measure-9 (PSM-9). Participants' pre- and postsession PSM-9 scores for three of the four sessions demonstrated a significant reduction in stress. Participants' baseline stress levels also decreased significantly across the four listening sessions. The greatest reductions in stress within and between sessions occurred in the early sessions, with effects diminishing over time. Pregnant teens experienced initial short- and long-term stress reduction during a guided imagery intervention, supporting the use of guided imagery to reduce stress in pregnant adolescents. Copyright © 2016 by the American Occupational Therapy Association, Inc.

ULTRACAVITATION METHOD OF EVALUATION IN THE REDUCTION OF LOCALIZED FAT IN WOMEN

OpenAIRE

L. Petraglia; D. R. X. O. Crege; J. L. Dullius; A. E. Bighetti

2017-01-01

This study evaluated cosmetic fat reduction methods that cause localized lipolysis and that are not invasive. The use of a differentiated ultrasound called Ultracavitation was evaluated, it causes reduction of localized fat in the infra abdominal region. 30 women aged 30-45 years old, healthy, sedentary were evaluated; they were separated into two groups subjected to 12 treatment sessions in infra abdominal region, once a week, alone or combined with aerobic exercise. Photographic recording w...

New Approaches to Anti-Stress Practices in Poultry

Directory of Open Access Journals (Sweden)

Atilla Taşkın

2015-07-01

Full Text Available Parameters of health, productivity, behaviour and physiology which are used in order to determine the stress shaped by the effects of various factors in poultries can only be detected when the effects of stress emerge; in other words, when the changes are shaped. Therefore; it is important to interfere before the emergence of these indications in order to develop animal welfare by preventing stress. Information programmes, as traditional methods, and vitamin applications as well as anti-stress effects of herbal extracts have recently been studied in order to reduce the effects of stress. Moreover; such applications as crossbreeding native race, which are highly tolerated against temperature stress, with the commercial ones, usage of blue LED light, capturing exercises, enriched environment, adding roosters into the flocks of hen and finally temperature exercises in chick period are also tried as anti-stress preventions. In this paper, new approaches to the reduction of stress or stress sensitivity in poultries have been studied.

A method to separate and quantify the effects of indentation size, residual stress and plastic damage when mapping properties using instrumented indentation

International Nuclear Information System (INIS)

Hou, X D; Jennett, N M

2017-01-01

Instrumented indentation is a convenient and increasingly rapid method of high resolution mapping of surface properties. There is, however, significant untapped potential for the quantification of these properties, which is only possible by solving a number of serious issues that affect the absolute values for mechanical properties obtained from small indentations. The three most pressing currently are the quantification of: the indentation size effect (ISE), residual stress, and pile-up and sink-in—which is itself affected by residual stress and ISE. Hardness based indentation mapping is unable to distinguish these effects. We describe a procedure that uses an elastic modulus as an internal reference and combines the information available from an indentation modulus map, a hardness map, and a determination of the ISE coefficient (using self-similar geometry indentation) to correct for the effects of stress, pile up and the indentation size effect, to leave a quantified map of plastic damage and grain refinement hardening in a surface. This procedure is used to map the residual stress in a cross-section of the machined surface of a previously stress free metal. The effect of surface grinding is compared to milling and is shown to cause different amounts of work hardening, increase in residual stress, and surface grain size reduction. The potential use of this procedure for mapping coatings in cross-section is discussed. (paper)

A method to separate and quantify the effects of indentation size, residual stress and plastic damage when mapping properties using instrumented indentation

Science.gov (United States)

Hou, X. D.; Jennett, N. M.

2017-11-01

Instrumented indentation is a convenient and increasingly rapid method of high resolution mapping of surface properties. There is, however, significant untapped potential for the quantification of these properties, which is only possible by solving a number of serious issues that affect the absolute values for mechanical properties obtained from small indentations. The three most pressing currently are the quantification of: the indentation size effect (ISE), residual stress, and pile-up and sink-in—which is itself affected by residual stress and ISE. Hardness based indentation mapping is unable to distinguish these effects. We describe a procedure that uses an elastic modulus as an internal reference and combines the information available from an indentation modulus map, a hardness map, and a determination of the ISE coefficient (using self-similar geometry indentation) to correct for the effects of stress, pile up and the indentation size effect, to leave a quantified map of plastic damage and grain refinement hardening in a surface. This procedure is used to map the residual stress in a cross-section of the machined surface of a previously stress free metal. The effect of surface grinding is compared to milling and is shown to cause different amounts of work hardening, increase in residual stress, and surface grain size reduction. The potential use of this procedure for mapping coatings in cross-section is discussed.

A proactive alarm reduction method and its human factors validation test for a main control room for SMART

International Nuclear Information System (INIS)

Jang, Gwi-sook; Suh, Sang-moon; Kim, Sa-kil; Suh, Yong-suk; Park, Je-yun

2013-01-01

Highlights: ► A proactive alarm reduction method improves effectiveness on the alarm reduction. ► The method suppresses alarms based on the ECA rules and facts for the alarm reduction under an alarm flood situation. ► The alarm reduction logics are supplemented to a high hit ratio of the reduction logics during on-line operations. ► The method is validated by human factors validation test based on regulatory requirements. -- Abstract: Conventional alarm systems tend to overwhelm operators during a transient because of a large number of nearly simultaneous annunciator activations with varying degrees of relevance to operator tasks. Thus alarm processing techniques have developed to support operators in coping with the volume of alarms, to identify which alarms are significant, and to reduce the need for operators to infer the plant conditions. This paper proposes a proactive alarm reduction method for SMART (System-integrated Modular Advanced ReacTor) whereby based on the contents of the past operating effects alarm reduction is carried out during the next transient. We designed and implemented the proactive alarm reduction system and constructed the environment for the human factors validation test. Also, eight subjects actually working in a nuclear power plant (NPP) tested the practical effectiveness of the proposed proactive alarm reduction method according to the procedure of human factors validation test under a dynamic simulation of a partial scope for an NPP.

Semiconductor/metal nanocomposites formed by in situ reduction method in multilayer thin films

International Nuclear Information System (INIS)

Song Yanli; Wang Enbo; Tian Chungui; Mao Baodong; Wang Chunlei

2009-01-01

A layer-by-layer adsorption and in situ reduction method was adopted for synthesizing semiconductor/metal nanocomposites in multilayer ultra-thin films. Alternate adsorption of ZnO nanoparticles modified with poly(ethyleneimine), hydrogentetrachloroaurate and poly(styrenesulfonate) sodium results in the formation of ZnO/AuCl 4 - -loaded multilayer films. In situ reduction of the incorporated metal ions by heating yields ZnO/Au nanocomposites in the films. UV-vis absorption spectroscopy and X-ray photoelectron spectroscopy were used to characterize the components of the composite films. UV-vis spectra indicate regular growth of the films. The electrochemistry behavior of the multilayer films was studied in detail on indium tin oxide electrode. The combined results suggest that the layer-by-layer adsorption and subsequent reduction method used here provides an effective way to synthesize ZnO/Au nanocomposites in the polymer matrix

Prediction method of long-term reliability in improving residual stresses by means of surface finishing

International Nuclear Information System (INIS)

Sera, Takehiko; Hirano, Shinro; Chigusa, Naoki; Okano, Shigetaka; Saida, Kazuyoshi; Mochizuki, Masahito; Nishimoto, Kazutoshi

2012-01-01

Surface finishing methods, such as Water Jet Peening (WJP), have been applied to welds in some major components of nuclear power plants as a counter measure to Primary Water Stress Corrosion Cracking (PWSCC). In addition, the methods of surface finishing (buffing treatment) is being standardized, and thus the buffing treatment has been also recognized as the well-established method of improving stress. On the other hand, the long-term stability of peening techniques has been confirmed by accelerated test. However, the effectiveness of stress improvement by surface treatment is limited to thin layers and the effect of complicated residual stress distribution in the weld metal beneath the surface is not strictly taken into account for long-term stability. This paper, therefore, describes the accelerated tests, which confirmed that the long-term stability of the layer subjected to buffing treatment was equal to that subjected to WJP. The long-term reliability of very thin stress improved layer was also confirmed through a trial evaluation by thermal elastic-plastic creep analysis, even if the effect of complicated residual stress distribution in the weld metal was excessively taken into account. Considering the above findings, an approach is proposed for constructing the prediction method of the long-term reliability of stress improvement by surface finishing. (author)

Study on application of green's function method in thermal stress rapid calculation

International Nuclear Information System (INIS)

Zhang Guihe; Duan Yuangang; Xu Xiao; Chen Rong

2013-01-01

This paper presents a quick and accuracy thermal stress calculation method, the Green's Function Method, which is a combination of finite element method and numerical algorithm method. Thermal stress calculation of Safe Injection Nozzle of Reactor Coolant Line of PWR plant is performed with Green's function method for heatup and cooldown thermal transients as a demonstration example, and the result is compared with finite element method to verify the rationality and accuracy of this method. The advantage and disadvantage of the Green's function method and the finite element method are also compared. (authors)

Thermal stress measurement in continuous welded rails using the hole-drilling method

Science.gov (United States)

Zhu, Xuan; Lanza di Scalea, Francesco; Fateh, Mahmood

2016-04-01

The absence of expansion joints in Continuous Welded Rail (CWR) has created the need for the railroad industry to determine the in-situ level of thermal stresses so as to prevent train accidents caused by rail buckling in hot weather and by rail breakage in cold weather. The development of non-destructive or semi-destructive methods for determining the level of thermal stresses in rails is today a high research priority. This study explores the known hole-drilling method as a possible solution to this problem. A new set of calibration coefficients to compute the relieved stress field with the finer hole depth increments was determined by a 3D Finite Element Analysis that modeled the entire hole geometry, including the mechanics of the hole bottom and walls. To compensate the residual stress components, a linear relationship was experimentally established between the longitudinal and the vertical residual stresses of two common sizes of rails, the 136RE and the 141RE, with statistical significance. This result was then utilized to isolate the longitudinal thermal stress component in hole-drilling tests conducted on the 136RE and 141RE thermally-loaded rails at the Large-scale CWR Test-bed of UCSD's Powell Research Laboratories. The results from the Test-bed showed that the hole-drilling procedure, with the appropriate residual stress compensation, can indeed estimate the in-situ thermal stresses to achieve a +/-5°F accuracy of Neutral Temperature determination with a 90% statistical confidence, which is the desired industry gold standard.

A New Invention Method to Determine the Reduction Factor for Low Fabric Tension Properties for Head Garment Fabrication

Directory of Open Access Journals (Sweden)

Aiman A.F

2016-01-01

Full Text Available This paper proposes a new method to determine the reduction factor for producing a head garment with specified targeted pressure output. Pressure garment fabric mostly supplied to the local hospitals with no information of the material properties and the fabrication method generally used a single reduction factor at various body segments. Reduction factor defined as the percentage of reducing the garment size from the original circumference of the body part which contributes to the compression. The objective of this study is to compare the fabrication method of head garment using reduction factor equation from previous research with the new proposed method. The equation to predict the reduction factor requires the parameter of the fabric tension which is obtained from tensile test and radius of curvature of the human body parts. In the new proposed method, a 3D scanning was used for data acquisition to obtain the geometry of the head area. The pressure outputs are measured by a pressure measurement system developed from Flexiforce sensor and Arduino circuit board. By using the equation, the result shows the calculated reduction factor produced an extremely tight head garment compared to the conducted experiments which manage to produce an adequate reduction factor with a targeted pressure output of 20mmHg. The result of the experiment indicates that the reduction factor ranging from 17% to 23% compared to the equation which produces 20% to 47% of reduction factor. As an additional, the proposed experimental method can be used for different type of pressure garment fabrics in order to obtain the relationship between the reduction factor and the circumference of the body parts.

Vertical Patellar Dislocation: Reduction by the Push Up and Rotate Method, A Case Report and Literature Review.

Science.gov (United States)

Ahmad Khan, Hayat; Bashir Shah, Adil; Kamal, Younis

2016-11-01

Patellar dislocation is an emergency. Vertical patellar dislocation is rare, often seen in adolescents and mostly due to sports injuries or high-velocity trauma. Few cases have been reported in the literature. Closed or open reduction under general anesthesia is often needed. We report a case of vertical locked patellar dislocation in a 26-year-old male, which was reduced by a simple closed method under spinal anaesthesia. A literature review regarding the various methods of treatment is also discussed. A 26-year-old male experienced a trivial accident while descending stairs, sustaining patellar dislocation. The closed method of reduction was attempted, using a simple technique. Reduction was confirmed and postoperative rehabilitation was started. Follow-up was uneventful. Vertical patellar dislocations are encountered rarely in the emergency department. Adolescents are not the only victims, and high-velocity trauma is not the essential cause. Unnecessary manipulation should be avoided. The closed reduction method is simple, but the surgeon should be prepared for open reduction.

Analysis of residual stress relief mechanisms in post-weld heat treatment

International Nuclear Information System (INIS)

Dong, Pingsha; Song, Shaopin; Zhang, Jinmiao

2014-01-01

This paper presents a recent study on weld residual stress relief mechanisms associated with furnace-based uniform post-weld heat treatment (PWHT). Both finite element and analytical methods are used to quantitatively examine how plastic deformation and creep relaxation contribute to residual stress relief process at different stages of PWHT process. The key contribution of this work to an improved understanding of furnace based uniform PWHT can be summarized as follows: (1)Plastic deformation induced stress relief during PWHT can be analytically expressed by the change in material elastic deformation capacity (or elastic deformation limit) measured in terms of material yield strength to Young's modulus ratio, which has a rather limited role in overall residual stress relief during furnace based uniform PWHT. (2)The most dominant stress relief mechanism is creep strain induced stress relaxation, as expected. However, a rapid creep strain development accompanied by a rapid residual stress reduction during heating stage before reaching PWHT temperature is shown to contribute to most of the stress relief seen in overall PWHT process, suggesting PWHT hold time can be significantly reduced as far as residual stress relief is concerned. (3)A simple engineering scheme for estimating residual stress reduction is proposed based on this study by relating material type, PWHT temperature, and component wall thickness. - Highlights: • The paper clarified effects of plastic deformation and creep relaxation on weld residual stress relief during uniform PWHT. • Creep strain development is far more important than plastic strain, mostly completed even before hold time starts. • Plastic strain development is insignificant and be analytically described by a material elastic deformation capacity parameter. • An engineering estimation scheme is proposed for determining residual stress reduction resulted from furnace based PWHT

The Induced Dimension Reduction method applied to convection-diffusion-reaction problems

NARCIS (Netherlands)

Astudillo, R.; Van Gijzen, M.B.

2016-01-01

Discretization of (linearized) convection-diffusion-reaction problems yields a large and sparse non symmetric linear system of equations, Ax = b. (1) In this work, we compare the computational behavior of the Induced Dimension Reduction method (IDR(s)) [10], with other short-recurrences Krylov

Measurement of heat treatment induced residual stresses by using ESPI combined with hole-drilling method

Directory of Open Access Journals (Sweden)

Jie Cheng

2010-08-01

Full Text Available In this study, residual stresses in heat treated specimen were measured by using ESPI (Electronic Speckle-Pattern Interferometry combined with the hole-drilling method. The specimen, made of SUS 304 austenitic stainless steel, was quenched and water cooled to room temperature. Numerical simulation using a hybrid FDM/FEM package was also carried out to simulate the heat treatment process. As a result, the thermal stress fields were obtained from both the experiment and the numerical simulation. By comparision of stress fields, results from the experimental method and numerical simulation well agreed to each other, therefore, it is proved that the presented experimental method is applicable and reliable for heat treatment induced residual stress measurement.

Feasibility of ultrasonic and eddy current methods for measurement of residual stress in shot peened metals

International Nuclear Information System (INIS)

Lavrentyev, Anton I.; Stucky, Paul A.; Veronesi, William A.

2000-01-01

Shot peening is a well-known method for extending the fatigue life of metal components by introducing compressive residual stresses near their surfaces. The capability to nondestructively evaluate the near surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper presents preliminary results from a feasibility study examining the use of ultrasonic and eddy current NDE methods for residual stress measurement in components where the stress has been introduced by shot peening. With an ultrasonic method, a variation of ultrasonic surface wave speed with shot peening intensity was measured. Near surface conductivity was measured by eddy current methods. Since the effective penetration depth of both methods employed is inversely related to the excitation frequency, by making measurements at different frequencies, each method has the potential to provide the stress-depth profile. Experiments were conducted on aluminum specimens (alloy 7075-T7351) peened within the Almen peening intensity range of 4C to 16C. The experimental results obtained demonstrate a correlation between peening intensity and Rayleigh wave velocity and between peening intensity and conductivity. The data suggests either of the methods may be suitable, with limitations, for detecting unsatisfactory levels of shot peening. Several factors were found to contribute to the measured responses: surface roughness, near surface plastic deformation (cold work) and residual stress. The contribution of each factor was studied experimentally. The feasibility of residual stress determination from the measured data is discussed

Work Stress Interventions in Hospital Care: Effectiveness of the DISCovery Method

Directory of Open Access Journals (Sweden)

Irene Niks

2018-02-01

Full Text Available Effective interventions to prevent work stress and to improve health, well-being, and performance of employees are of the utmost importance. This quasi-experimental intervention study presents a specific method for diagnosis of psychosocial risk factors at work and subsequent development and implementation of tailored work stress interventions, the so-called DISCovery method. This method aims at improving employee health, well-being, and performance by optimizing the balance between job demands, job resources, and recovery from work. The aim of the study is to quantitatively assess the effectiveness of the DISCovery method in hospital care. Specifically, we used a three-wave longitudinal, quasi-experimental multiple-case study approach with intervention and comparison groups in health care work. Positive changes were found for members of the intervention groups, relative to members of the corresponding comparison groups, with respect to targeted work-related characteristics and targeted health, well-being, and performance outcomes. Overall, results lend support for the effectiveness of the DISCovery method in hospital care.

Work Stress Interventions in Hospital Care: Effectiveness of the DISCovery Method.

Science.gov (United States)

Niks, Irene; de Jonge, Jan; Gevers, Josette; Houtman, Irene

2018-02-13

Effective interventions to prevent work stress and to improve health, well-being, and performance of employees are of the utmost importance. This quasi-experimental intervention study presents a specific method for diagnosis of psychosocial risk factors at work and subsequent development and implementation of tailored work stress interventions, the so-called DISCovery method. This method aims at improving employee health, well-being, and performance by optimizing the balance between job demands, job resources, and recovery from work. The aim of the study is to quantitatively assess the effectiveness of the DISCovery method in hospital care. Specifically, we used a three-wave longitudinal, quasi-experimental multiple-case study approach with intervention and comparison groups in health care work. Positive changes were found for members of the intervention groups, relative to members of the corresponding comparison groups, with respect to targeted work-related characteristics and targeted health, well-being, and performance outcomes. Overall, results lend support for the effectiveness of the DISCovery method in hospital care.

Work Stress Interventions in Hospital Care: Effectiveness of the DISCovery Method

Science.gov (United States)

Niks, Irene; Gevers, Josette

2018-01-01

Effective interventions to prevent work stress and to improve health, well-being, and performance of employees are of the utmost importance. This quasi-experimental intervention study presents a specific method for diagnosis of psychosocial risk factors at work and subsequent development and implementation of tailored work stress interventions, the so-called DISCovery method. This method aims at improving employee health, well-being, and performance by optimizing the balance between job demands, job resources, and recovery from work. The aim of the study is to quantitatively assess the effectiveness of the DISCovery method in hospital care. Specifically, we used a three-wave longitudinal, quasi-experimental multiple-case study approach with intervention and comparison groups in health care work. Positive changes were found for members of the intervention groups, relative to members of the corresponding comparison groups, with respect to targeted work-related characteristics and targeted health, well-being, and performance outcomes. Overall, results lend support for the effectiveness of the DISCovery method in hospital care. PMID:29438350

Analysis of macro and micro residual stresses in functionally graded materials by diffraction methods

CERN Document Server

Dantz, D; Reimers, W

1999-01-01

The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO/sub 2//Ni and 8Y-ZrO/sub 2//NiCr8020, respectively, was analysed by non- destructive diffraction methods. In $9 order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using $9 conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion $9 (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. (7 refs).

A study on the Stress Corrosion Cracking reduction method of Steam Generator secondary side of KSNP

International Nuclear Information System (INIS)

Kim, June Hoon; Lee, Goune Jin

2014-01-01

In order to avoid sludge accumulation affecting the life of the steam generator, the best way is to prevent the sludge inflow in advance by optimization of water quality management through chemical concentration and pH control etc. However it is very difficult to prevent sludge accumulation under the weak condition of corrosion, such as condensation, boiling and high temperature of feed-water in NPPs. Particularly stress corrosion cracking occurs in a top-of-tube sheet area of steam generator with an increase in number of operation years of Korea Standard Nuclear Plant(KSNP)... The purpose of this study is to improve suppression of stress corrosion cracking and life extension for steam generator and improve plant efficiency by performing full length bulk high chemical cleaning in order to remove iron oxide of steam generator secondary side in KSNP Hanbit Unit 6. This study analyzed the Free EDTA and Fe concentrations and sludge removal after performed full length bulk high temperature chemical cleaning for removing the iron oxide of steam generator secondary side, which of Hanbit unit 6 of KSNP. 1) It showed a typical pattern that Fe concentration increased in accordance with to decrease Free EDTA(Ethylene Diamine Tetea acetic Acid) concentration. 2) Sludge removal based on iron oxide after performing the full length bulk high temperature chemical cleaning was 3001kg and sludge removal by lancing additionally was 200.1kg

[Evaluation methods in the work/stress correlations in law enforcement].

Science.gov (United States)

Magnavital, Nicola; Garbarino, Sergio; Siegrist, Johannes

2014-01-01

Stress in police: assessment methods. Police work is unanimously considered stressful. Prevention of stress in police is of the utmost importance, as a distressed officer could be hazardous for third parties. There is scientific evidence that the relationship between occupational stressors and their psychological and physical consequences can be described by Karasek's demand-control-support (DCS) model and the effort / reward imbalance (ERI) model of Siegrist. This study summarizes the results of surveys conducted using the DCS and ERI questionnaires.on police officers from the VI Mobile Unit of Genoa who were engaged in public order management at the G8 summit in L'Aquila in 2009. In spite of the high alert due to expected threats to public order during the G8 meeting, police officers were not affected by "distress". When the policemen were compared to other categories of workers, their stress levels were in the lowest range. In most cases, the personality profile of these workers did not differ substantially from that of the general population. There was an association between personality and stress response. The levels of perceived stress were significantly associated with absence from work. The prevalence of mental disorders in police officers was significantly lower than that of the general population. Occupational stress was associated with indicators of depression, anxiety and burnout. The DCS and ERI models yielded complementary results and proved to be effective in assessing the effects of stress in law enforcement. The extent of perceived stress does not directly depend on external events, but on the way in which these are handled: routine work may be more stressful than a single critical event. Special police forces are particularly resilient to stress, partly due to the characteristics and personality of individual officers, but mainly on account of their training. Occupational stress is associated with a lower level of psychological well-being and an

Analysis of Stress Updates in the Material-point Method

DEFF Research Database (Denmark)

Andersen, Søren; Andersen, Lars

2009-01-01

The material-point method (MPM) is a new numerical method for analysis of large strain engineering problems. The MPM applies a dual formulation, where the state of the problem (mass, stress, strain, velocity etc.) is tracked using a finite set of material points while the governing equations...... are solved on a background computational grid. Several references state, that one of the main advantages of the material-point method is the easy application of complicated material behaviour as the constitutive response is updated individually for each material point. However, as discussed here, the MPM way...

Bolt Thread Stress Optimization

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2012-01-01

of threads and therefore indirectly the bolt fatigue life. The root shape is circular, and from shape optimization for minimum stress concentration it is well known that the circular shape is seldom optimal. An axisymmetric Finite Element (FE) formulation is used to analyze the bolted connection, and a study...... is performed to establish the need for contact modeling with regard to finding the correct stress concentration factor. Optimization is performed with a simple parameterization with two design variables. Stress reduction of up to 9% is found in the optimization process, and some similarities are found...... in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool....

A new method of residual stress distribution analysis for corroded Zircaloy-4 cladding

International Nuclear Information System (INIS)

Godlewski, J.; Cadalbert, R.

1992-01-01

An X-ray diffraction method of residual stress measurement is developed to determine the stress level in the metal near the metal/oxide interface of Zircaloy-4 cladding samples oxidized in steam water at 400degC under a pressure of 10.3 MPa. The stress gradient is obtained and the evolution of the average stress is determined as function of the oxidation time. The presence of tetragonal zirconia phase in quite large quantity near the metal/oxide interface could be correlated to the high stress level in the base metal, adjacent to the interface. (author)

A new method for residual stress distribution - analysis of corroded zircaloy-4 cladding

International Nuclear Information System (INIS)

Godlewski, J.; Cadalbert, R.

1992-01-01

An X-ray diffraction method for residual stress measurement is developed to determine the stress level in the metal near the metal/oxide interface of Zircaloy-4 cladding samples oxidized in steam water at 400 deg C under a pressure of 10.3 MPa. The stress gradient is obtained and the evolution of the average stress is determined as a function of the oxidation time. The presence of tetragonal zirconia phase in quite large quantity near the metal/oxide interface could be correlated to the high stress level in the base metal, adjacent to the interface. 12 refs., 5 figs., 1 tab

The induced dimension reduction method applied to convection-diffusion-reaction problems

NARCIS (Netherlands)

Astudillo Rengifo, R.A.; van Gijzen, M.B.

2016-01-01

Discretization of (linearized) convection-diusion-reaction problems yields
a large and sparse non symmetric linear system of equations,
Ax = b: (1)
In this work, we compare the computational behavior of the Induced Dimension
Reduction method (IDR(s)) [10], with other

Stress and Fatigue Management Using Balneotherapy in a Short-Time Randomized Controlled Trial

Science.gov (United States)

Razbadauskas, Artūras; Sąlyga, Jonas; Martinkėnas, Arvydas

2016-01-01

Objective. To investigate the influence of high-salinity geothermal mineral water on stress and fatigue. Method. 180 seamen were randomized into three groups: geothermal (65), music (50), and control (65). The geothermal group was administered 108 g/L salinity geothermal water bath for 2 weeks five times a week. Primary outcome was effect on stress and fatigue. Secondary outcomes were the effect on cognitive function, mood, and pain. Results. The improvements after balneotherapy were a reduction in the number and intensity of stress-related symptoms, a reduction in pain and general, physical, and mental fatigue, and an improvement in stress-related symptoms management, mood, activation, motivation, and cognitive functions with effect size from 0.8 to 2.3. In the music therapy group, there were significant positive changes in the number of stress symptoms, intensity, mood, pain, and activity with the effect size of 0.4 to 1.1. The researchers did not observe any significant positive changes in the control group. The comparison between the groups showed that balneotherapy was superior to music therapy and no treatment group. Conclusions. Balneotherapy is beneficial for stress and fatigue reduction in comparison with music or no therapy group. Geothermal water baths have a potential as an efficient approach to diminish stress caused by working or living conditions. PMID:27051455

Stress and Fatigue Management Using Balneotherapy in a Short-Time Randomized Controlled Trial

Directory of Open Access Journals (Sweden)

Lolita Rapolienė

2016-01-01

Full Text Available Objective. To investigate the influence of high-salinity geothermal mineral water on stress and fatigue. Method. 180 seamen were randomized into three groups: geothermal (65, music (50, and control (65. The geothermal group was administered 108 g/L salinity geothermal water bath for 2 weeks five times a week. Primary outcome was effect on stress and fatigue. Secondary outcomes were the effect on cognitive function, mood, and pain. Results. The improvements after balneotherapy were a reduction in the number and intensity of stress-related symptoms, a reduction in pain and general, physical, and mental fatigue, and an improvement in stress-related symptoms management, mood, activation, motivation, and cognitive functions with effect size from 0.8 to 2.3. In the music therapy group, there were significant positive changes in the number of stress symptoms, intensity, mood, pain, and activity with the effect size of 0.4 to 1.1. The researchers did not observe any significant positive changes in the control group. The comparison between the groups showed that balneotherapy was superior to music therapy and no treatment group. Conclusions. Balneotherapy is beneficial for stress and fatigue reduction in comparison with music or no therapy group. Geothermal water baths have a potential as an efficient approach to diminish stress caused by working or living conditions.

Verification of intraspecimen method using constant stress tension test of sensitized alloy 600

International Nuclear Information System (INIS)

Lee, Seung Ki; Choi, Hoi Su; Hwang, Il Soon

2005-01-01

Stress corrosion cracking (SCC) occurring at the Nibase alloy 600 used in the nuclear power plant SG tubes and CRDM penetration nozzles had been reported after long-term operation in the harsh environment. Intraspecimen method was developed to predict the SCC initiation time statistically. [1] By dividing a test area into a number of smaller regions (intraspecimens) having homogeneous physical and chemical condition each SCC initiation in each intraspecimen could be counted as an independent outcome to provide enough number of statistical data. Earlier work of intraspecimen method had many problems in test method and didn't agree with Weibull statistics which is the theoretical base of intraspecimen method. The test method is improved in this intraspecimen test. To find out the root causes of the problems in earlier work and improve the accuracy of intraspecimen method, two kinds of materials are introduced, which are different in grain size but same in chemical composition. Ni-base alloy 600, heat no. J313 and J323 are used as test materials. Specimens of sensitized Alloy 600 are tested under the condition of constant tensile stress and well defined chemical environment therefore we can easily observe typical intergranular stress corrosion cracking (IGSCC). Material with finer grain (J323) showed the areadependence in agreement with theoretical prediction. But material with coarser grain (J313) did not show any significant area-dependence. While SCC initiates earlier at grain boundaries that are oriented close to normal to the stress axis, crack initiation time showed no correlation with grain boundary misorientation estimated by Electron Back Scattered Diffraction (EBSD). From the SCC initiation tests with two test materials, it is concluded that the number of grains in an intraspecimen, degree of sensitization and uniform stress distribution are important parameters to meet Weibull statistics