Work-related musculoskeletal symptoms among motorcycle mechanics, Lahore (Pakistan: an application of standardized Nordic questionnaire

Directory of Open Access Journals (Sweden)

Mujtaba Baqar

2017-06-01

Full Text Available The current study is a follow up to our previously published “letter to the editor”, whose purpose was to report the relationship of pain prevalence (work-related musculoskeletal symptoms and trouble prohibiting to normal work (work-related musculoskeletal disorders with descriptive variables among motorcycle mechanics using standardized Nordic musculoskeletal questionnaire (NMQ as a tool. Results demonstrates that the pain prevalence was significantly high in shoulders, neck, low-back, wrists, ankles and elbows compared to other body parts. Among variables “age of participants and working hours” were found to be directly associated whereby shoulder and neck pain had significant correlation with lower age groups and more working hours. Regarding trouble prohibited to normal work, a total of 121 (46% participants reported hindrance in normal work with serious complaints about shoulders for younger age group; wrists and hips for middle age group; and neck, lower back, knees, ankles for old age group. Finally, results of a frequencies and cross-tabulations indicated that prolong work hours were significantly associated with emergence of musculoskeletal symptoms. This high prevalence of WMSS leading to WMSD among the motorcycles mechanics reflects the ignorance of occupational duties. A possible recommendation of this research includes the development and implementation of health and safety guidelines for the mentioned industry.

Contribution of psychological, social, and mechanical work exposures to low work ability: a prospective study.

Science.gov (United States)

Emberland, Jan S; Knardahl, Stein

2015-03-01

To determine the contribution of specific psychological, social, and mechanical work exposures to the self-reported low level of work ability. Employees from 48 organizations were surveyed over a 2-year period (n = 3779). Changes in 16 work exposures and 3 work ability measures-the work ability index score, perceived current, and future work ability-were tested with Spearman rank correlations. Binary logistic regressions were run to determine contribution of work exposures to low work ability. Role conflict, human resource primacy, and positive challenge were the most consistent predictors of low work ability across test designs. Role clarity and fair leadership were less consistent but prominent predictors. Mechanical exposures were not predictive. To protect employee work ability, work place interventions would benefit from focusing on reducing role conflicts and on promoting positive challenges and human resource primacy.

Linking Mechanisms of Work-Family Conflict and Segmentation

Science.gov (United States)

Michel, Jesse S.; Hargis, Michael B.

2008-01-01

Despite the abundance of work and family research, few studies have compared the linking mechanisms specified in theoretical models of work-family conflict and segmentation. Accordingly, the current study provides a greater degree of empirical clarity concerning the interplay of work and family by directly examining the indirect effects of…

Summary of rock mechanics work completed for Posiva before 2005

International Nuclear Information System (INIS)

Hudson, J.A.; Johansson, E.

2006-06-01

To plan Posiva's rock mechanics work for 2005-2006 and beyond, it was necessary to have a clear understanding of the individual components of work that had been completed for Posiva before 2005 and to assess the cumulative rock mechanics knowledge base. This review summarizes the 80 individual completed documents, which include rock mechanics reports and other reports containing rock mechanics material. They are summarised within a structured framework of rock properties, analyses and the effects of excavation. Following the introductory section, the method of structuring the rock mechanics information is presented. Then the tabulation highlighting the features of all the previous rock mechanics work is explained. This tabulation forms the Appendix; the content of each rock mechanics report that has been produced is summarized via the table headings of document number, subject area, document reference, subject matter, objectives, methodology, highlighted figures, conclusions and comments. In addition to the direct usefulness of the tabulation in summarizing each report, it has been possible to draw overall conclusions: Information has also been obtained worldwide, especially Sweden and Canada; The rock stress state has been measured but further work is required related both to in situ measurements and numerical modelling to study, e.g., the influence of deformation zones on the local stress state; The intact rock has been extensively studied: there is a good knowledge of the parameters and their values, including the anisotropic nature of the site rocks; The geometry of the fractures is included in the geological characterisation but more rock mechanics work is required on the mechanical properties; The mechanical properties of the deformation zones have not been studied in detail; The thermal properties of the site rock are relatively well understood; A new classification has been developed for constructability and long-term safety assessment. This classification

Cold forging stem of total hip prosthesis with hybrid mechanical properties

International Nuclear Information System (INIS)

Lopes, E.S.N.; Contieri, R.J.; Cardoso, F.F.; Cremasco, A.; Button, S.T.; Caram, R.

2010-01-01

Type β Ti alloy is one of the most versatile groups of materials with regard to mechanical properties. Aspects such as alloying elements selection, mechanical processing and heat treatment routes empower these materials in applications where hybrid mechanical behavior is necessary. The aim of this study is to produce stems of total hip prostheses with hybrid mechanical properties using Ti-Nb alloys. Ingots were produced by using arc melting. Following, samples were subjected to specific heat treatment aiming to make cold forging. Sample characterization includes X-ray diffraction, scanning electron microscopy, Vickers hardness tests and tensile test. The experiments performed allowed to examine the effects of heat treatment parameters on the microstructure and mechanical behavior. Finally, results obtained show that the application of specific heat treatments of quenching and aging makes feasible the manufacturing of orthopedic devices with hybrid mechanical properties with regions where high mechanical strength was prioritized, while in others, low elastic modulus was the main concern. (author)

Abrasive wear mechanisms and surface layer structure of refractory materials after mechanical working

International Nuclear Information System (INIS)

Milman, Y.V.; Lotsko, D.V.

1989-01-01

The mechanisms of abrasive wear and surface layer structure formation after different kinds of mechanical working are considered in terms of fracture and plastic deformation mechanisms for various refractory materials. The principles for classification of abrasive wear mechanisms are proposed, the four types of wear mechanisms are distinguished for various combinations of fractures and plastic deformation types. The concept of characteristic deformation temperature t * (knee temperature) is used. Detailed examples are given of investigating the surface layer structures in grinded crystals of sapphire and molybdenum. The amorphisation tendency of the thinnest surface layer while mechanical polishing is discussed separately. 19 refs., 11 figs., 2 tabs. (Author)

Mechanical properties of carbynes investigated by ab initio total-energy calculations

DEFF Research Database (Denmark)

Castelli, Ivano E.; Salvestrini, Paolo; Manini, Nicola

2012-01-01

As sp carbon chains (carbynes) are relatively rigid molecular objects, can we exploit them as construction elements in nanomechanics? To answer this question, we investigate their remarkable mechanical properties by ab initio total-energy simulations. In particular, we evaluate their linear...

Different but Equal: Total Work, Gender and Social Norms in EU and US Time Use

OpenAIRE

Daniel S Hamermesh; Michael C Burda; Philippe Weil

2008-01-01

Using time-diary data from 27 countries, we demonstrate a negative relationship between real GDP per capita and the female-male difference in total work time—the sum of work for pay and work at home. We also show that in rich non-Catholic countries on four continents men and women do the same amount of total work on average. Our survey results demonstrate that labor economists, macroeconomists, sociologists and the general public consistently believe that women perform more tot...

Objectively measured total and occupational sedentary time in three work settings

NARCIS (Netherlands)

Dommelen, P. van; Coffeng, J. K.; Ploeg, H.P. van der; Beek, A.J. van der; Boot, C.R.; Hendriksen, I.J.

2016-01-01

Background. Sedentary behaviour increases the risk for morbidity. Our primary aim is to determine the proportion and factors associated with objectively measured total and occupational sedentary time in three work settings. Secondary aim is to study the proportion of physical activity and prolonged

Return to work and workplace activity limitations following total hip or knee replacement.

Science.gov (United States)

Sankar, A; Davis, A M; Palaganas, M P; Beaton, D E; Badley, E M; Gignac, M A

2013-10-01

Total hip (THR) and knee (TKR) replacements increasingly are performed on younger people making return to work a salient outcome. This research evaluates characteristics of individuals with early and later return to work following THR and TKR. Additionally, at work limitations pre-surgery and upon returning to work, and factors associated with work limitations were evaluated. 190 THR and 170 TKR of a total 931 cohort participants were eligible (i.e., working or on short-term disability pre-surgery). They completed questionnaires pre-surgery and 1, 3, 6 and 12 months post-surgery that included demographics, type of occupation, and the Workplace Activity Limitations Scale (WALS). 166 (87%) and 144 (85%) returned to work by 12 months following THR and TKR, respectively. Early (1 month) return to work was associated with, male gender, university education, working in business, finance or administration, and low physical demand work. People with THR returned to work earlier than those with TKR. For both groups, less pain and every day functional limitations were associated with less workplace activity limitations at the time return to work. The majority of individuals working prior to surgery return to work following hip or knee replacement for osteoarthritis (OA) and experience fewer limitations at work than pre-surgery. The changing workforce dynamics and trends toward surgery at younger ages mean that these are important outcomes for clinicians to assess. Additionally, this is important information for employers in understanding continued participation in employment for people with OA. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Coordination of push-off and collision determine the mechanical work of step-to-step transitions when isolated from human walking.

Science.gov (United States)

Soo, Caroline H; Donelan, J Maxwell

2012-02-01

In human walking, each transition to a new stance limb requires redirection of the center of mass (COM) velocity from one inverted pendulum arc to the next. While this can be accomplished with either negative collision work by the leading limb, positive push-off work by the trailing limb, or some combination of the two, physics-based models of step-to-step transitions predict that total positive work is minimized when the push-off and collision work are equal in magnitude. Here, we tested the importance of the coordination of push-off and collision work in determining transition work using ankle and knee joint braces to limit the ability of a leg to perform positive work on the body. To isolate transitions from other contributors to walking mechanics, participants were instructed to rock back and forth from one leg to the other, restricting motion to the sagittal plane and eliminating the need to swing the legs. We found that reduced push-off work increased the collision work required to complete the redirection of the COM velocity during each transition. A greater amount of total mechanical work was required when rocking departed from the predicted optimal coordination of step-to-step transitions, in which push-off and collision work are equal in magnitude. Our finding that transition work increases if one or both legs do not push-off with the optimal coordination may help explain the elevated metabolic cost of pathological gait irrespective of etiology. Copyright © 2011 Elsevier B.V. All rights reserved.

Working mechanisms of computer-tailored health education : evidence from smoking cessation

NARCIS (Netherlands)

Dijkstra, A.

2005-01-01

To further develop tailored interventions, their working mechanisms must be identified. In the present study, three tailored messages that each contained one potential working mechanism-personalization, adaptation or feedback-were compared with a standard information condition. Two hundred and two

Objectively Measured Total and Occupational Sedentary Time in Three Work Settings

Science.gov (United States)

van Dommelen, Paula; Coffeng, Jennifer K.; van der Ploeg, Hidde P.; van der Beek, Allard J.; Boot, Cécile R. L.; Hendriksen, Ingrid J. M.

2016-01-01

Background Sedentary behaviour increases the risk for morbidity. Our primary aim is to determine the proportion and factors associated with objectively measured total and occupational sedentary time in three work settings. Secondary aim is to study the proportion of physical activity and prolonged sedentary bouts. Methods Data were obtained using ActiGraph accelerometers from employees of: 1) a financial service provider (n = 49 men, 31 women), 2) two research institutes (n = 30 men, 57 women), and 3) a construction company (n = 38 men). Total (over the whole day) and occupational sedentary time, physical activity and prolonged sedentary bouts (lasting ≥30 minutes) were calculated by work setting. Linear regression analyses were performed to examine general, health and work-related factors associated with sedentary time. Results The employees of the financial service provider and the research institutes spent 76–80% of their occupational time in sedentary behaviour, 18–20% in light intensity physical activity and 3–5% in moderate-to-vigorous intensity physical activity. Occupational time in prolonged sedentary bouts was 27–30%. Total time was less sedentary (64–70%), and had more light intensity physical activity (26–33%). The employees of the construction company spent 44% of their occupational time in sedentary behaviour, 49% in light, and 7% in moderate intensity physical activity, and spent 7% in sedentary bouts. Total time spent in sedentary behavior was 56%, 40% in light, and 4% in moderate intensity physical behaviour, and 12% in sedentary bouts. For women, low to intermediate education was the only factor that was negatively associated with occupational sedentary time. Conclusions Sedentary behaviour is high among white-collar employees, especially in highly educated women. A relatively small proportion of sedentary time was accrued in sedentary bouts. It is recommended that worksite health promotion efforts should focus on reducing sedentary

Total and domain-specific sitting time among employees in desk-based work settings in Australia.

Science.gov (United States)

Bennie, Jason A; Pedisic, Zeljko; Timperio, Anna; Crawford, David; Dunstan, David; Bauman, Adrian; van Uffelen, Jannique; Salmon, Jo

2015-06-01

To describe the total and domain-specific daily sitting time among a sample of Australian office-based employees. In April 2010, paper-based surveys were provided to desk-based employees (n=801) in Victoria, Australia. Total daily and domain-specific (work, leisure-time and transport-related) sitting time (minutes/day) were assessed by validated questionnaires. Differences in sitting time were examined across socio-demographic (age, sex, occupational status) and lifestyle characteristics (physical activity levels, body mass index [BMI]) using multiple linear regression analyses. The median (95% confidence interval [CI]) of total daily sitting time was 540 (531-557) minutes/day. Insufficiently active adults (median=578 minutes/day, [95%CI: 564-602]), younger adults aged 18-29 years (median=561 minutes/day, [95%CI: 540-577]) reported the highest total daily sitting times. Occupational sitting time accounted for almost 60% of total daily sitting time. In multivariate analyses, total daily sitting time was negatively associated with age (unstandardised regression coefficient [B]=-1.58, pphysical activity (minutes/week) (B=-0.03, pemployees reported that more than half of their total daily sitting time was accrued in the work setting. Given the high contribution of occupational sitting to total daily sitting time among desk-based employees, interventions should focus on the work setting. © 2014 Public Health Association of Australia.

The mechanism of total disintegration of heavy nuclei by fast hadrons and nuclei

International Nuclear Information System (INIS)

Strugalska-Gola, E.; Strugalski, Z.

1997-01-01

The mechanism of the total disintegration of atomic nuclei by fast hadrons and nuclei is considered. The passage of energetic hadrons through layers of intranuclear matter, accompanied by emission of fast nucleons with kinetic energies from about 20 up to about 500 MeV from definite local small regions in the nuclei around projectile courses in them, allows one to explain simply the occurrence of the total destruction of nuclei involved in the collisions. Light nuclei may be totally disintegrated by fast hadrons and nuclei; heavier nuclei may be totally disintegrated only in central collisions of nuclei with similar mass numbers

Comparison of total hip arthroplasty in osteoarthritis of mechanical and rheumatologic causes

Science.gov (United States)

Ejnisman, Leandro; Leonhardt, Nathalia Zalc; Fernandes, Laura Fillipini Lorimier; Leonhardt, Marcos de Camargo; Vicente, José Ricardo Negreiros; Croci, Alberto Tesconi

2014-01-01

Objective: To compare the use of uncemented implants in total hip arthroplasty in patients with rheumathologic diseases and mechanical osteoarthrosis. Methods: We retrospectively evaluated 196 patients who were operated by the Hip and Arthroplasty Surgery Group of the IOT-HCFMUSP between 2005 and 2009. Patients were divided into two groups: mechanical causes (165 patients) and rheumathologic causes (31 patients). Groups were compared between each other in age, gender and follow-up time. Osseointegration rate and percentage of failure in arthroplasty were evaluated. Results: No statistically significant difference was found in osseointegration rates (in both femoral and acetabular components) in both groups. The rates of revision surgery and implant survival also did not show statistically significant differences. Conclusion: The use of uncemented total hip arthroplasty did not show worse results in rheumathologic patients. Level of Evidence III, Retrospective Case Control Study. PMID:24644419

Human Error Mechanisms in Complex Work Environments

DEFF Research Database (Denmark)

Rasmussen, Jens

1988-01-01

will account for most of the action errors observed. In addition, error mechanisms appear to be intimately related to the development of high skill and know-how in a complex work context. This relationship between errors and human adaptation is discussed in detail for individuals and organisations...

Post-cam mechanics and tibiofemoral kinematics: a dynamic in vitro analysis of eight posterior-stabilized total knee designs.

Science.gov (United States)

Arnout, N; Vanlommel, L; Vanlommel, J; Luyckx, J P; Labey, L; Innocenti, B; Victor, J; Bellemans, J

2015-11-01

Posterior cruciate ligament (PCL)-substituting total knee arthroplasty (TKA) designs were introduced to avoid paradoxical roll forward of the femur and to optimize knee kinematics. The aim of this in vitro study was to investigate post-cam function and contact mechanics and relate it to knee kinematics during squatting in eight contemporary posterior-stabilized TKA designs. All prostheses were fixed on custom-designed metal fixtures and mounted in a knee rig and five sequential-loaded squats were performed between 30° and 130° of flexion. Contact pressure and contact area were measured using pressure-sensitive Tekscan sensors on the posterior face of the post. Kinematics was recorded with reflective markers and infrared light-capturing cameras. The post-cam mechanisms analyzed in this study are very variable in terms of design features. This leads to large variations in terms of the flexion angle at which the post and cam engage maximal contact force, contact pressure and contact area. We found that more functional post-cam mechanisms, which engage at lower flexion angle and have a similar behavior as normal PCL function, generally show more normal rollback and tibial rotation at the expense of higher contact forces and pressures. All designs show high contact forces. A positive correlation was found between contact force and initial contact angle. Post-cam contact mechanics and kinematics were documented in a standardized setting. Post-cam contact mechanics are correlated with post-cam function. Outcomes of this study can help to develop more functional designs in future. Nevertheless, a compromise will always be made between functional requirements and risk of failure. We assume that more normal knee kinematics leads to more patient satisfaction because of better mobility. Understanding of the post-cam mechanism, and knowing how this system really works, is maybe the clue in further development of new total knee designs.

History of Virtual Work Laws A History of Mechanics Prospective

CERN Document Server

Capecchi, Danilo

2012-01-01

 The book presents a history of classical mechanics by focusing on issues of equilibrium. The historical point of view adopted here restricts attention to cases where the effectiveness of forces is assessed on the basis of the virtual motion of their points of application. For completeness, hints of the alternative approach are also referred, the Archimedean for ancient mechanics and the Newtonian for modern mechanics. The laws resulting from consideration of virtual motions are named laws of virtual work. The modern formulations of the principle of virtual work are only a particular form of them. The book begins with the first documented formulations of laws of virtual work in the IV century BC in Greece and proceeds to the end of the XIX century AD in Europe. A significant space is devoted to Arabic and Latin mechanics of Middle Ages. With the Renaissance it began to appear slightly different wordings of the laws, which were often proposed as unique principles of statics. The process reached its apex with ...

Working principle and structure characteristics analysis of the reactivity control drive mechanism

International Nuclear Information System (INIS)

Zhao Tianyu; Huang Zhiyong; Chen Feng; He Xuedong

2010-01-01

The startup, power regulation and safety shutdown of the nuclear reactor are operated by the reactivity control devices. Reactivity control drive mechanism is a key mechanical transmission component, which directly control the location of the neutron absorber in the core. Its working condition is complex, and its service life should be long., which requires high reliability. PWR as well as newly developed different type of reactors have different control devices drive mechanism. This paper mainly do analysis and comparison about the working environment, mechanical transmission principle, structure, performance, service life and other aspects of PWR, HTR control devices drive mechanism. In addition, this paper is also based on the working principles of reactive control devices drive mechanism, also consider the trends of its design and test verification by the international countries, and discussed the method and feasibility of improving and perfecting the structure and function of drive mechanism. (authors)

Human error mechanisms in complex work environments

International Nuclear Information System (INIS)

Rasmussen, J.

1988-01-01

Human error taxonomies have been developed from analysis of industrial incident reports as well as from psychological experiments. In this paper the results of the two approaches are reviewed and compared. It is found, in both cases, that a fairly small number of basic psychological mechanisms will account for most of the action errors observed. In addition, error mechanisms appear to be intimately related to the development of high skill and know-how in a complex work context. This relationship between errors and human adaptation is discussed in detail for individuals and organisations. The implications for system safety and briefly mentioned, together with the implications for system design. (author)

Human error mechanisms in complex work environments

International Nuclear Information System (INIS)

Rasmussen, Jens; Danmarks Tekniske Hoejskole, Copenhagen)

1988-01-01

Human error taxonomies have been developed from analysis of industrial incident reports as well as from psychological experiments. In this paper the results of the two approaches are reviewed and compared. It is found, in both cases, that a fairly small number of basic psychological mechanisms will account for most of the action errors observed. In addition, error mechanisms appear to be intimately related to the development of high skill and know-how in a complex work context. This relationship between errors and human adaptation is discussed in detail for individuals and organisations. The implications for system safety are briefly mentioned, together with the implications for system design. (author)

Selective attention on representations in working memory: cognitive and neural mechanisms.

Science.gov (United States)

Ku, Yixuan

2018-01-01

Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory.

Interactive mechanism of working environments and construction behaviors with cognitive work analysis: an elevator installation case study.

Science.gov (United States)

Wang, Yanqing; Chong, Heap-Yih; Liao, Pin-Chao; Ren, Hantao

2017-09-25

Unsafe behavior is a leading factor in accidents, and the working environment significantly affects behaviors. However, few studies have focused on detailed mechanisms for addressing unsafe behaviors resulting from environmental constraints. This study aims to delineate these mechanisms using cognitive work analysis (CWA) for an elevator installation case study. Elevator installation was selected for study because it involves operations at heights: falls from heights remain a major cause of construction worker mortality. This study adopts a mixed research approach based on three research methodology stages. This research deconstructs the details of the working environment, the workers' decision-making processes, the strategies chosen given environmental conditions and the conceptual model for workers' behaviors, which jointly depict environment-behavior mechanisms at length. By applying CWA to the construction industry, environmental constraints can easily be identified, and targeted engineering suggestions can be generated.

Changes in Energy Cost and Total External Work of Muscles in Elite Race Walkers Walking at Different Speeds

Directory of Open Access Journals (Sweden)

Chwała Wiesław

2014-12-01

Full Text Available The aim of the study was to assess energy cost and total external work (total energy depending on the speed of race walking. Another objective was to determine the contribution of external work to total energy cost of walking at technical, threshold and racing speed in elite competitive race walkers.

Models of working memory:Mechanisms of active maintenance and executive control (1999 Models of working memory:Mechanisms of active maintenance and executive control (1999

Directory of Open Access Journals (Sweden)

Augusto Buchweitz

2008-04-01

Full Text Available What is working memory, anyway?’ Despite the seminal definition (Baddeley & Hitch 1974; Daneman & Carpenter 1980 of working memory (WM being the system or mechanism at the basis of maintaining task-relevant information during the performance of a cognitive task (p. 1, and despite the familiarity of the term, addressing the question of what WM really is does not seem to be in the same ballpark of easily-put answers; it is not even in the same league. What is working memory, anyway?’ Despite the seminal definition (Baddeley & Hitch 1974; Daneman & Carpenter 1980 of working memory (WM being the system or mechanism at the basis of maintaining task-relevant information during the performance of a cognitive task (p. 1, and despite the familiarity of the term, addressing the question of what WM really is does not seem to be in the same ballpark of easily-put answers; it is not even in the same league.

Selective attention on representations in working memory: cognitive and neural mechanisms

Directory of Open Access Journals (Sweden)

Yixuan Ku

2018-04-01

Full Text Available Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory.

Virtual work and shape change in solid mechanics

CERN Document Server

Frémond, Michel

2017-01-01

This book provides novel insights into two basic subjects in solid mechanics: virtual work and shape change. When we move a solid, the work we expend in moving it is used to modify both its shape and its velocity. This observation leads to the Principle of Virtual Work. Virtual work depends linearly on virtual velocities, which are velocities we may think of. The virtual work of the internal forces accounts for the changes in shape. Engineering provides innumerable examples of shape changes, i.e., deformations, and of velocities of deformation. This book presents examples of usual and unusual shape changes, providing with the Principle of Virtual Work various and sometimes new equations of motion for smooth and non-smooth (i.e., with collisions) motions: systems of disks, systems of balls, classical and non-classical small deformation theories, systems involving volume and surface damage, systems with interactions at a distance (e.g., solids reinforced by fibers), systems involving porosity, beams with third ...

Energy cost and mechanical work of walking during load carriage in soldiers.

Science.gov (United States)

Grenier, Jordane G; Peyrot, Nicolas; Castells, Josiane; Oullion, Roger; Messonnier, Laurent; Morin, Jean-Benoit

2012-06-01

In the military context, soldiers carry equipments of total mass often exceeding 30%-40% of their body mass (BM) and complexly distributed around their body (backpack, weapons, electronics, protections, etc.), which represents severe load carrying conditions. This study aimed to better understand the effects of load carriage on walking energetics and mechanics during military-type walking. Ten male infantrymen recently retired from the French Foreign Legion performed 3-min walking trials at a constant speed of 4 km·h(-1) on an instrumented treadmill, during which walking pattern spatiotemporal parameters, energy cost (C(W)), external mechanical work (W(ext)), and the work done by one leg against the other during the double-contact period (W(int,dc)) were specifically assessed. Three conditions were tested: (i) light sportswear (SP, reference condition considered as unloaded), (ii) battle equipment (BT, ∼22 kg, ∼27% of subjects' BM, corresponding to a military intermediate load), and (iii) road march equipment (RM, ∼38 kg, ∼46% of subjects' BM, corresponding to a military high load). Repeated-measures ANOVA showed that military equipment carriage significantly (i) altered the spatiotemporal pattern of walking (all P < 0.01), (ii) increased absolute gross and net CW (P < 0.0001), and (iii) increased both absolute and mass-relative W(ext) (P < 0.01) and W(int,dc) (P < 0.0001) but did not alter the inverted pendulum recovery or locomotor efficiency. Military equipments carriage induced significant changes in walking mechanics and energetics, but these effects appeared not greater than those reported with loads carried around the waist and close to the center of mass. This result was not expected because the latter has been hypothesized to be the optimal method of load carriage from a metabolic standpoint.

Accidents of Electrical and Mechanical Works for Public Sector Projects in Hong Kong.

Science.gov (United States)

Wong, Francis K W; Chan, Albert P C; Wong, Andy K D; Hon, Carol K H; Choi, Tracy N Y

2018-03-10

A study on electrical and mechanical (E&M) works-related accidents for public sector projects provided the opportunity to gain a better understanding of the causes of accidents by analyzing the circumstances of all E&M works accidents. The research aims to examine accidents of E&M works which happened in public sector projects. A total of 421 E&M works-related accidents in the "Public Works Programme Construction Site Safety and Environmental Statistics" (PCSES) system were extracted for analysis. Two-step cluster analysis was conducted to classify the E&M accidents into different groups. The results identified three E&M accidents groups: (1) electricians with over 15 years of experience were prone to 'fall of person from height'; (2) electricians with zero to five years of experience were prone to 'slip, trip or fall on same level'; (3) air-conditioning workers with zero to five years of experience were prone to multiple types of accidents. Practical measures were recommended for each specific cluster group to avoid recurrence of similar accidents. The accident analysis would be vital for industry practitioners to enhance the safety performance of public sector projects. This study contributes to filling the knowledge gap of how and why E&M accidents occur and promulgating preventive measures for E&M accidents which have been under researched.

Accidents of Electrical and Mechanical Works for Public Sector Projects in Hong Kong

Directory of Open Access Journals (Sweden)

Francis K. W. Wong

2018-03-01

Full Text Available A study on electrical and mechanical (E&M works-related accidents for public sector projects provided the opportunity to gain a better understanding of the causes of accidents by analyzing the circumstances of all E&M works accidents. The research aims to examine accidents of E&M works which happened in public sector projects. A total of 421 E&M works-related accidents in the “Public Works Programme Construction Site Safety and Environmental Statistics” (PCSES system were extracted for analysis. Two-step cluster analysis was conducted to classify the E&M accidents into different groups. The results identified three E&M accidents groups: (1 electricians with over 15 years of experience were prone to ‘fall of person from height’; (2 electricians with zero to five years of experience were prone to ‘slip, trip or fall on same level’; (3 air-conditioning workers with zero to five years of experience were prone to multiple types of accidents. Practical measures were recommended for each specific cluster group to avoid recurrence of similar accidents. The accident analysis would be vital for industry practitioners to enhance the safety performance of public sector projects. This study contributes to filling the knowledge gap of how and why E&M accidents occur and promulgating preventive measures for E&M accidents which have been under researched.

Accidents of Electrical and Mechanical Works for Public Sector Projects in Hong Kong

Science.gov (United States)

Wong, Francis K. W.; Chan, Albert P. C.; Wong, Andy K. D.; Choi, Tracy N. Y.

2018-01-01

A study on electrical and mechanical (E&M) works-related accidents for public sector projects provided the opportunity to gain a better understanding of the causes of accidents by analyzing the circumstances of all E&M works accidents. The research aims to examine accidents of E&M works which happened in public sector projects. A total of 421 E&M works-related accidents in the “Public Works Programme Construction Site Safety and Environmental Statistics” (PCSES) system were extracted for analysis. Two-step cluster analysis was conducted to classify the E&M accidents into different groups. The results identified three E&M accidents groups: (1) electricians with over 15 years of experience were prone to ‘fall of person from height’; (2) electricians with zero to five years of experience were prone to ‘slip, trip or fall on same level’; (3) air-conditioning workers with zero to five years of experience were prone to multiple types of accidents. Practical measures were recommended for each specific cluster group to avoid recurrence of similar accidents. The accident analysis would be vital for industry practitioners to enhance the safety performance of public sector projects. This study contributes to filling the knowledge gap of how and why E&M accidents occur and promulgating preventive measures for E&M accidents which have been under researched. PMID:29534429

Simulation of the filtration mechanism of hyaluronic acid in total knee prosthesis

International Nuclear Information System (INIS)

Paolo, J Di; Berli, M E; Campana, D M; Ubal, S; Cardenes, L D

2007-01-01

Polyethylene (UHMWPE) wear in current knee prosthesis causes prosthesis loosening after no more than 15 years. In this work, a steady state one-dimensional lubrication model with non- Newtonian fluid, porous elastic layer on tibial component, ultra-filtration mechanism of fluid and some features of the surface roughness is studied through a numerical technique based on the Finite Element Method. The results show that the UHMWPE stiffness makes difficult the lubrication mechanism of the artificial joint and promotes abrasive and fatigue wear. Nevertheless, the use of compliant porous materials on the tibial component could reduce friction and wear. Moreover, the ultra-filtration mechanism promotes efficiency on the joint

Objectively Measured Total and Occupational Sedentary Time in Three Work Settings

OpenAIRE

van Dommelen, Paula; Coffeng, Jennifer K.; van der Ploeg, Hidde P.; van der Beek, Allard J.; Boot, C?cile R. L.; Hendriksen, Ingrid J. M.

2016-01-01

Background. Sedentary behaviour increases the risk for morbidity. Our primary aim is to determine the proportion and factors associated with objectively measured total and occupational sedentary time in three work settings. Secondary aim is to study the proportion of physical activity and prolonged sedentary bouts. Methods. Data were obtained using ActiGraph accelerometers from employees of: 1) a financial service provider (n = 49 men, 31 women), 2) two research institutes (n = 30 men, 57 wom...

Generation Mechanism of Work Hardened Surface Layer in Metal Cutting

Science.gov (United States)

Hikiji, Rikio; Kondo, Eiji; Kawagoishi, Norio; Arai, Minoru

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

The assessment of chronic health conditions on work performance, absence, and total economic impact for employers.

Science.gov (United States)

Collins, James J; Baase, Catherine M; Sharda, Claire E; Ozminkowski, Ronald J; Nicholson, Sean; Billotti, Gary M; Turpin, Robin S; Olson, Michael; Berger, Marc L

2005-06-01

The objective of this study was to determine the prevalence and estimate total costs for chronic health conditions in the U.S. workforce for the Dow Chemical Company (Dow). Using the Stanford Presenteeism Scale, information was collected from workers at five locations on work impairment and absenteeism based on self-reported "primary" chronic health conditions. Survey data were merged with employee demographics, medical and pharmaceutical claims, smoking status, biometric health risk factors, payroll records, and job type. Almost 65% of respondents reported having one or more of the surveyed chronic conditions. The most common were allergies, arthritis/joint pain or stiffness, and back or neck disorders. The associated absenteeism by chronic condition ranged from 0.9 to 5.9 hours in a 4-week period, and on-the-job work impairment ranged from a 17.8% to 36.4% decrement in ability to function at work. The presence of a chronic condition was the most important determinant of the reported levels of work impairment and absence after adjusting for other factors (P < 0.000). The total cost of chronic conditions was estimated to be 10.7% of the total labor costs for Dow in the United States; 6.8% was attributable to work impairment alone. For all chronic conditions studied, the cost associated with performance based work loss or "presenteeism" greatly exceeded the combined costs of absenteeism and medical treatment combined.

The Total Work Measured During a High Intensity Isokinetic Fatigue Test Is Associated With Anaerobic Work Capacity

Directory of Open Access Journals (Sweden)

Laurent Bosquet, Kenan Gouadec, Nicolas Berryman, Cyril Duclos, Vincent Gremeaux, Jean Louis Croisier

2016-03-01

Full Text Available The purpose of the study was to determine whether total work measured during a high intensity isokinetic fatigue test (TWFAT could be considered as a valid measure of anaerobic work capacity (AWC, such as determined by total work measured during a Wingate Anaerobic Test (TWWAnT. Twenty well-trained cyclists performed 2 randomly ordered sessions involving a high intensity isokinetic fatigue test consisting in 30 reciprocal maximal concentric contractions of knee flexors and extensors at 180°·s-1, and a Wingate Anaerobic Test. We found that TWFAT of knee extensors was largely lower than TWWAnT (4151 ± 691 vs 22313 ± 2901 J, respectively, p < 0.05, Hedge’s g = 4.27. Both measures were highly associated (r = 0.83, and the 95% limits of agreement (LoA represented 24.5% of TWWAnT. TWFAT of knee flexors (2151 ± 540 J was largely lower than TWWAnT (p < 0.05, g = 9.52. By contrast, both measures were not associated (r = 0.09, and the 95% LoA represented 31.1% of TWWAnT. Combining TWFAT of knee flexors and knee extensors into a single measure (6302 ± 818 J did not changed neither improved these observations. We still found a large difference with TWWAnT (p < 0.05, g = 5.26, a moderate association (r = 0.65 and 95% LoA representing 25.5% of TWWAnT. We concluded that TWFAT of knee extensors could be considered as a valid measure of AWC, since both measure were highly associated. However, the mean difference between both measures and their 95% LoA were too large to warrant interchangeability.

Work stressors and partner social undermining: Comparing negative affect and psychological detachment as mechanisms.

Science.gov (United States)

Meier, Laurenz L; Cho, Eunae

2018-05-14

With the mounting evidence that employees' work experiences spill over into the family domain and cross over to family members, it is important to understand the underlying mechanism through which work experiences affect the family domain and what factors may alleviate the adverse impact of work stress. Expanding previous research that mainly focused on the affect-based mechanism (negative affect), the present research investigated a resource-based mechanism (psychological detachment from work) in the relationship linking two work stressors (high workload and workplace incivility) with social undermining toward the partner at home. We also explored the relative strength of the mediating effects of the two mechanisms. In addition, we tested whether relationship satisfaction moderates the proposed effect of detachment on partner undermining. We tested these research questions using two studies with differing designs: a five-wave longitudinal study (N = 470) and a multisource study (N = 131). The results suggest that stressful work experiences affect the family domain via lack of detachment as well as negative affect, that the two pathways have comparable strength, and that high relationship satisfaction mitigates the negative effect of lack of detachment on partner undermining. In sum, this research extends the spillover-crossover model by establishing that poor psychological detachment from work during leisure time is an additional mechanism that links work and family. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Influence of working fluids on startup mechanism and thermal performance of a closed loop pulsating heat pipe

International Nuclear Information System (INIS)

Patel, Vipul M.; Gaurav; Mehta, Hemantkumar B.

2017-01-01

Highlights: • Startup mechanism and thermal performance of a CLPHP is reported. • Influence of pure fluids, water-based binary fluids and surfactant solutions are investigated. • Startup heat flux is observed lower for acetone and higher for water compared to all other working fluids. • Thermal resistance is observed to decrease with increase in heat input irrespective of working fluids. • CLPHP is observed to perform better with acetone, water-acetone, water-45 PPM and water-60 PPM surfactant solutions. - Abstract: Development of efficient cooling system is a tricky and challenging task in the field of electronics. Pulsating heat pipe has a great prospect in the upcoming days for an effective cooling solution due to its excellent heat transfer characteristics. Experimental investigations are reported on a Closed Loop Pulsating Heat Pipe (CLPHP). The influence of working fluids on startup mechanism and thermal performance of a CLPHP are carried out on 2 mm, nine turn copper capillary. Total eleven (11) working fluids are prepared and investigated. Deionized (DI) Water (H_2O), ethanol (C_2H_6O), methanol (CH_3OH) and acetone (C_3H_6O) are used as pure fluids. The water-based mixture (1:1) of acetone, methanol and ethanol are used as binary fluids. Sodium Dodecyl Sulphate (SDS, NaC_1_2H_2_5SO_4) is used as a surfactant to prepare the water-based surfactant solutions of 30 PPM, 45 PPM, 60 PPM and 100 PPM. The filling ratio is kept as 50%. The vertical bottom heating position of a CLPHP is considered. Heat input is varied in the range of 10–110 W. Significant influence is observed for water-based binary fluids and surfactant solutions on startup mechanism and thermal performance of a CLPHP compared to DI water used as the pure working fluid.

A novel hybrid actuation mechanism based XY nanopositioning stage with totally decoupled kinematics

Science.gov (United States)

Zhu, Wu-Le; Zhu, Zhiwei; Guo, Ping; Ju, Bing-Feng

2018-01-01

This paper reports the design, analysis and testing of a parallel two degree-of-freedom piezo-actuated compliant stage for XY nanopositioning by introducing an innovative hybrid actuation mechanism. It mainly features the combination of two Scott-Russell and a half-bridge mechanisms for double-stage displacement amplification as well as moving direction modulation. By adopting the leaf-type double parallelogram (LTDP) structures at both input and output ends of the hybrid mechanism, the lateral stiffness and dynamic characteristics are significantly improved while the parasitic motions are greatly eliminated. The XY nanopositioning stage is constructed with two orthogonally configured hybrid mechanisms along with the LTDP mechanisms for totally decoupled kinematics at both input and output ends. An analytical model was established to describe the complete elastic deformation behavior of the stage, with further verification through the finite element simulation. Finally, experiments were implemented to comprehensively evaluate both the static and dynamic performances of the proposed stage. Closed-loop control of the piezoelectric actuators (PEA) by integrating strain gauges was also conducted to effectively eliminate the nonlinear hysteresis of the stage.

Proposing and Planning the Rehabilitation Works of Mechanical Utility System in Malaysian Nuclear Agency

International Nuclear Information System (INIS)

Jusnan Hasim; Mohamad Suhaimi Yahaya; Abdul Razak Hashim

2015-01-01

Nuclear Malaysia has 2 complex located in Bangi and Jalan Dengkil. The utility in Nuclear Malaysia consists of civil, mechanical and electrical system that has been managed by Bahagian Kejuruteraan (BKJ). The mechanical utilities system has been divided to three main groups which are the main system, supporting system and safety equipment's. The objectives of this paper are to propose and plan the rehabilitation works of mechanical utility system in Nuclear Malaysia and also to explain working procedures in maintaining and repairing the mechanical utility system. The study suggest the rehabilitation works on the mechanical utilities system especially on Thermal Energy Storage (TES) and domestic water system needs to be done which involve process of design, procurement, installation and commissioning. (author)

UKAEA mechanical test work in sodium

International Nuclear Information System (INIS)

Wood, D.S.

1977-01-01

The main aim of the UKAEA work is to perform mechanical tests in high quality sodium, and on the basis of relatively long term tests to establish whether factors need to be applied to the air data for the design and assessment of components which will have to operate in sodium for up to 30 years. Most of the tests will be performed in sodium containing 5-10 ppm O 2 and ∼ 1 ppm C with a flow rate over the specimen surface of 3m/sec. Some work is also planned to establish the effect of changes in oxygen level up to 30 ppm on the properties and carburization studies will also be performed. Thin work has been in progress on a limited scale for 2-3 years but is now increasing in magnitude to meet the programme requirements. The materials under test include Type 316 steel and 9% Cr steel with most emphasis being placed on the austenitic steel. From the very limited fatigue and stress rupture tests so far performed on Type 316 steel there is no evidence to suggest that high purity sodium may be detrimental. Longer term tests are necessary however to confirm this finding which is based on results from relatively short term tests. Tests are also necessary in less pure sodium

Extensor Mechanism Disruption after Total Knee Arthroplasty: A Case Series and Review of Literature.

Science.gov (United States)

Vaishya, Raju; Agarwal, Amit Kumar; Vijay, Vipul

2016-02-04

Extensor mechanism disruption following total knee arthroplasty (TKA) is a rare but devastating complication. These patients may require revision of the implants, but even then, it may not be possible to restore the normal function of the knee after the disruption. The patterns of extensor mechanism disruption can broadly be classified into three types: suprapatellar (quadriceps tendon rupture), transpatellar (patellar fracture), or infrapatellar (patellar tendon rupture). Infrapatellar tendon ruptures are the worst injuries, as they carry maximum morbidity and are challenging to manage. The disruption of the extensor mechanism may occur either intra-operatively or in the immediate postoperative period due to an injury. The treatment of extensor mechanism complications after TKA may include either nonsurgical management or surgical intervention in the form of primary repair or reconstruction with autogenous, allogeneic, or synthetic substitutes. We have provided an algorithm for the management of extensor mechanism disruption after TKA.

Two Maintenance Mechanisms of Verbal Information in Working Memory

Science.gov (United States)

Camos, V.; Lagner, P.; Barrouillet, P.

2009-01-01

The present study evaluated the interplay between two mechanisms of maintenance of verbal information in working memory, namely articulatory rehearsal as described in Baddeley's model, and attentional refreshing as postulated in Barrouillet and Camos's Time-Based Resource-Sharing (TBRS) model. In four experiments using complex span paradigm, we…

Return to work after total hip and knee arthroplasty: results from a clinical study.

Science.gov (United States)

Tilbury, C; Leichtenberg, C S; Tordoir, R L; Holtslag, M J; Verdegaal, S H M; Kroon, H M; Nelissen, R G H H; Vliet Vlieland, T P M

2015-12-01

The aim of this study was to measure return to work and duration until return to work in patients undergoing total hip or knee arthroplasty (THA or TKA). This prospective study included patients under 65 years of age, undergoing THA or TKA, who provided information on their work status preoperatively (paid work yes/no and working hours) and 1 year thereafter (paid work yes/no, working hours and time until return to work). Seventy-one THA and 64 TKA patients had a paid job preoperatively. The employment rates 1 year postoperatively were 64/71 (90 %) after THA and 53/64 (83 %) after TKA. Of those who returned to work, 9/64 (14 %) of THA patients and 10/53 (19 %) of TKA patients worked less hours than preoperatively [mean decrease of 16 (SD 11.5) and 14 (SD 13.0) hours, respectively]. The mean time to return to work was 12.5 (SD 7.6) and 12.9 (SD 8.0) weeks in THA and TKA, respectively. The majority of working patients who underwent THA or TKA returned to work, after approximately 12 weeks. A considerable proportion of the patients returning to work worked less hours than preoperatively. More research into patients who do not return or decrease their working hours is needed.

Cold forging stem of total hip prosthesis with hybrid mechanical properties; Forjamento a frio de hastes de protese total de quadril com propriedades mecanicas hibridas

Energy Technology Data Exchange (ETDEWEB)

Lopes, E.S.N.; Contieri, R.J.; Cardoso, F.F.; Cremasco, A.; Button, S.T.; Caram, R., E-mail: ederlopes@fem.unicamp.b [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais

2010-07-01

Type {beta} Ti alloy is one of the most versatile groups of materials with regard to mechanical properties. Aspects such as alloying elements selection, mechanical processing and heat treatment routes empower these materials in applications where hybrid mechanical behavior is necessary. The aim of this study is to produce stems of total hip prostheses with hybrid mechanical properties using Ti-Nb alloys. Ingots were produced by using arc melting. Following, samples were subjected to specific heat treatment aiming to make cold forging. Sample characterization includes X-ray diffraction, scanning electron microscopy, Vickers hardness tests and tensile test. The experiments performed allowed to examine the effects of heat treatment parameters on the microstructure and mechanical behavior. Finally, results obtained show that the application of specific heat treatments of quenching and aging makes feasible the manufacturing of orthopedic devices with hybrid mechanical properties with regions where high mechanical strength was prioritized, while in others, low elastic modulus was the main concern. (author)

Mechanical Properties and Microstructure of Neutron Irradiated Cold-worked Al-1050 and Al-6063 Alloys

International Nuclear Information System (INIS)

Munitz, A.; Cotler, A; Talianker, M.

1998-01-01

The impact of neutron irradiation on the internal microstructure, mechanical properties and fracture morphology of cold-worked Al-1050 and Al-6063 alloys was studied, using scanning and transmission electron microscopy, and tensile measurements. Specimens consisting of 50 mm long and 6 mm wide gauge sections, were punched out from Al-1050 and Al-6063 23% cold-worked tubes. They were exposed to prolonged neutron irradiation of up to 4.5x10 25 and 8x10 25 thermal neutrons/m 2 (E -3 s -1 . In general, the uniform and total elongation, the yield stress, and the ultimate tensile strength increase as functions of fluence. However, for Al-1050 a decrease in the ultimate tensile strength and yield stress was observed up to a fluence of 1x10 25 thermal neutrons/m 2 which then increase with thermal neutrons fluence. Metallographic examination and fractography for Al-6063 revealed a decrease in the local area reduction of the final fracture necking. This reduction is accompanied by a morphology transition from ductile transgranular shear rupture to a combination of transgranular shear with intergranular dimpled rupture. The intergranular rupture area increases with fluence. In contrast, for Al-1050, fracture morphology remains ductile transgranular shear rupture and the final local area reduction remains almost constant No voids could be observed in either alloy up to the maximum fluence. The dislocation density of cold-worked Al was found to decrease with the thermal neutron fluence. Prolonged annealing of unirradiated cold-worked Al-6063 at 52 degree led to similar results. Thus, it appears that, under our irradiation conditions, whereby the temperature encompassing the samples increases the exposure to this thermal field is the major factor influencing the mechanical properties and microstructure of aluminum alloys

Effect of cold work and aging on mechanical properties of a copper ...

Indian Academy of Sciences (India)

Unknown

Influence of cold working and aging on the mechanical properties of a ... toughness and ductility in various stages of cold work and aging may include high stress concentration at high ... copper is added to HSLA steels to cause precipitation.

Effects and Mechanisms of Total Flavonoids from Blumea balsamifera (L. DC. on Skin Wound in Rats

Directory of Open Access Journals (Sweden)

Yuxin Pang

2017-12-01

Full Text Available Chinese herbal medicine (CHM evolved through thousands of years of practice and was popular not only among the Chinese population, but also most countries in the world. Blumea balsamifera (L. DC. as a traditional treatment for wound healing in Li Nationality Medicine has a long history of nearly 2000 years. This study was to evaluate the effects of total flavonoids from Blumea balsamifera (L. DC. on skin excisional wound on the back of Sprague-Dawley rats, reveal its chemical constitution, and postulate its action mechanism. The rats were divided into five groups and the model groups were treated with 30% glycerol, the positive control groups with Jing Wan Hong (JWH ointment, and three treatment groups with high dose (2.52 g·kg−1, medium dose (1.26 g·kg−1, and low dose (0.63 g·kg−1 of total flavonoids from B. balsamifera. During 10 consecutive days of treatment, the therapeutic effects of rates were evaluated. On day 1, day 3, day 5, day 7, and day 10 after treatment, skin samples were taken from all the rats for further study. Significant increases of granulation tissue, fibroblast, and capillary vessel proliferation were observed at day 7 in the high dose and positive control groups, compared with the model group, with the method of 4% paraformaldehyde for histopathological examination and immunofluorescence staining. To reveal the action mechanisms of total flavonoids on wound healing, the levels of CD68, vascular endothelial growth factor (VEGF, transforming growth factor-β1 (TGF-β1, and hydroxyproline were measured at different days. Results showed that total flavonoids had significant effects on rat skin excisional wound healing compared with controls, especially high dose ones (p < 0.05. Furthermore, the total flavonoid extract was investigated phytochemically, and twenty-seven compounds were identified from the total flavonoid sample by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass

Assessment and validation of CT scanogram to compare per-operative and post-operative mechanical axis after navigated total knee replacement

Science.gov (United States)

Jain, Sunil

2008-01-01

Our objective was to assess and validate low-dose computed tomography (CT) scanogram as a post-operative imaging modality to measure the mechanical axis after navigated total knee replacement. A prospective study was performed to compare intra-operative and post-operative mechanical axis after navigated total knee replacements. All consecutive patients who underwent navigated total knee replacement between May and December 2006 were included. The intra-operative final axis was recorded, and post-operatively a CT scanogram of lower limbs was performed. The mechanical axis was measured and compared against the intra-operative measurement. There were 15 patients ranging in age from 57 to 80 (average 70) years. The average final intra-operative axis was 0.56° varus (4° varus to 1.5° valgus) and post-operative CT scanogram axis was 0.52° varus (3.1° varus to 1.8° valgus). The average deviation from final axes to CT scanogram axes was 0.12° valgus with a correlation coefficient of 0.9. Our study suggests that CT scanogram is an imaging modality with reasonable accuracy for measuring mechanical axis despite significantly low radiation. It also confirms a high level of correlation between intra-operative and post-operative mechanical axis after navigated total knee replacement. PMID:18696064

Neural mechanisms of interference control in working memory capacity.

Science.gov (United States)

Bomyea, Jessica; Taylor, Charles T; Spadoni, Andrea D; Simmons, Alan N

2018-02-01

The extent to which one can use cognitive resources to keep information in working memory is known to rely on (1) active maintenance of target representations and (2) downregulation of interference from irrelevant representations. Neurobiologically, the global capacity of working memory is thought to depend on the prefrontal and parietal cortices; however, the neural mechanisms involved in controlling interference specifically in working memory capacity tasks remain understudied. In this study, 22 healthy participants completed a modified complex working memory capacity task (Reading Span) with trials of varying levels of interference control demands while undergoing functional MRI. Neural activity associated with interference control demands was examined separately during encoding and recall phases of the task. Results suggested a widespread network of regions in the prefrontal, parietal, and occipital cortices, and the cingulate and cerebellum associated with encoding, and parietal and occipital regions associated with recall. Results align with prior findings emphasizing the importance of frontoparietal circuits for working memory performance, including the role of the inferior frontal gyrus, cingulate, occipital cortex, and cerebellum in regulation of interference demands. © 2017 Wiley Periodicals, Inc.

Application of SolidWorks Plastic in the Training in Mechanical Engineering

Directory of Open Access Journals (Sweden)

Maria Ivanova Bakalova

2017-12-01

Full Text Available Abstract. In this article is presented an example of the application of SolidWorks the training in mechanical engineering. The main features of the design of the parts intended for injection molding are mentioned. SolidWorks allows all these recommendations to be implemented when creating the details. The text explains the simulation settings that are made in SolidWorks Plastics when simulating injection molding. Through a specific example referred to how to make an analysis of the results obtained.

Conversion of thermall energy to mechanical work in the oscillations with steam condensation in pool water

International Nuclear Information System (INIS)

Aya, Izuo; Nariai, Hideki.

1988-01-01

Pressure and fluid oscillations with steam injection into pool water were discussed from the view point of the conversion of thermal energy into mechanical work. When the change of fluid state moves clockwise in the p-V diagram, the oscillation sustains since the thermal energy changes into positive work. The equations difining the mechanical work at the condensation oscillations were presented. The oscillation threshold determined by the condition that mechanical work became zero, coincided with the values derived by the linear oscillation theory. The changes of pressure and specific volume during chugging were also shown with one dimensional simulation analysis. The p-V diagrams at various chugging modes were presented with the movement of steam water interface, and the conversion efficiency of thermal energy to mechanical work was also discussed. (author)

Fracture of the proximal tibia after revision total knee arthroplasty with an extensor mechanism allograft.

Science.gov (United States)

Klein, Gregg R; Levine, Harlan B; Sporer, Scott M; Hartzband, Mark A

2013-02-01

Extensor mechanism reconstruction with an extensor mechanism allograft (EMA) remains one of the most reliable methods for treating the extensor mechanism deficient total knee arthroplasty. We report 3 patients who were treated with an EMA who sustained a proximal tibial shaft fracture. In all 3 cases, a short tibial component was present that ended close to the level of the distal extent of the bone block. When performing an EMA, it is important to recognize that the tibial bone block creates a stress riser and revision to a long-stemmed tibial component should be strongly considered to bypass this point to minimize the risk of fracture. Copyright © 2013 Elsevier Inc. All rights reserved.

Market mechanisms for compensating hazardous work: a critical analysis

International Nuclear Information System (INIS)

Shakow, D.

1984-01-01

Adam Smith's theory that the marketplace can compensate workers for social inequities (i.e., hazards, boredom, etc.) in the work place is applied to the nuclear industry. The author argues that market mechanisms are unlikely to ensure adequate compensation for work-related hazards. He summarizes and critiques the neoclassical compensating-wage hypothesis, then reviews empirical evidence in support of the hypothesis in light of an alternative hypothesis derived from the literature on labor market segmentation. He challenges the assumption of perfect labor mobility and perfect information. A promising direction for further research would be a structural analysis of the emerging market for temporary workers. 13 references, 2 figures

Working group inciting mechanisms

International Nuclear Information System (INIS)

Bureau, D.

2001-01-01

This document deals with the inciting mechanisms under consideration in the framework of the greenhouse effect fight. The advantages and disadvantages, the coherence of these mechanisms and their articulation with the taxation, have been specified. A whole evaluation of the various scenario, taking into account the implementing problems and the evolution in an international context, is proposed. (A.L.B.)

Different mechanisms to explain the reversed effects of mental health on work characteristics

NARCIS (Netherlands)

Lange, A.H. de; Taris, T.W.; Kompier, M.A.J.; Houtman, I.L.D.; Bongers, P.M.

2005-01-01

Objectives: The number of longitudinal studies reporting evidence for reversed effects of strain on work is growing, but evidence regarding the mechanisms underlying such effects is scarce. In this study, earlier longitudinal findings were reviewed, and the following four mechanisms for reversed

Total workload, work stress and perceived symptoms in Swedish male and female white-collar employees.

Science.gov (United States)

Krantz, Gunilla; Berntsson, Leeni; Lundberg, Ulf

2005-04-01

The aim of this study was to analyse how paid work, unpaid household tasks, child care, work-child care interactions and perceived work stress are associated with reported symptoms in male and female white-collar employees. A questionnaire was mailed to 1300 men and 1300 women belonging to the white-collar sector, with at least 35 hours of regular employment a week and a participant age of between 32 and 58 years. It contained items relating to total workload (hours spent on paid work, unpaid household tasks and childcare), subjective indices for work stress and symptoms. The response rate was 65% (743 women; 595 men). Gender difference in symptom prevalence was tested by analyses of variance. Odds ratios were used to estimate the bivariate associations between work-related variables and symptom prevalence. A multivariate analysis estimated the effect of paid and unpaid work interaction, work-childcare interplay and possible synergy. The frequency and severity of symptoms was higher in women than in men (P women's health was determined by the interaction between conditions at work and household duties (OR 2.09; 1.06-4.14), whereas men responded more selectively to long working hours, i.e. >50 h/week (OR 1.61; 1.02-2.54). However, childcare (women.

Work and neck pain: a prospective study of psychological, social, and mechanical risk factors.

Science.gov (United States)

Christensen, Jan Olav; Knardahl, Stein

2010-10-01

To determine the impact of occupational psychological/social and mechanical factors on neck pain, a prospective cohort study with a follow-up period of 2 years was conducted with a sample of Norwegian employees. The following designs were tested: (i) cross-sectional analyses at baseline (n=4569) and follow-up (n=4122), (ii) prospective analyses with baseline predictors, (iii) prospective analyses with average exposure over time [(T1+T2)/2] as predictor, and (iv) prospective analyses with measures of change in exposure from T1 to T2 as predictors. A total of 2419 employees responded to both the baseline and follow-up questionnaire. Data were analyzed using ordinal logistic regression. After adjustment for age, sex, neck pain at T1, and other exposure factors that had been estimated to be confounders, the most consistent risk factors were role conflict (highest OR 2.97, 99% CI: 1.29-6.74) and working with arms raised to or above shoulder level (highest OR 1.37, 99% CI: 1.05-1.78). The most consistent protective factors were empowering leadership (lowest OR 0.53, 99% CI: 0.35-0.81) and decision control (lowest OR 0.60, 99% CI: 0.36-1.00). Hence, psychological and social factors are important precursors of neck pain, along with mechanical factors. Although traditional factors such as quantitative demands and decision control play a part in the etiology of neck pain at work, in this study several new factors emerged as more important. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

ACPSEM ROSG TBI working group recommendations for quality assurance in total body irradiation

International Nuclear Information System (INIS)

Nelligan, Raelene; Bailey, Michael; Tran, Thu; Baldwin, Zoe

2015-01-01

The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) radiation oncology specialty group (ROSG) formed a series of working groups in 2011 to develop recommendations for guidance of radiation oncology medical physics practice within the Australasian setting. These recommendations are intended to provide guidance for safe work practices and a suitable level of quality control without detailed work instructions. It is the responsibility of the medical physicist to ensure that locally available equipment and procedures are sufficiently sensitive to establish compliance to these recommendations. The recommendations are endorsed by the ROSG, and have been subject to independent expert reviews. For the Australian audience, these recommendations should be read in conjunction with the tripartite radiation oncology practice standards [1, 2]. This publication presents the recommendations of the ACPSEM total body irradiation working group (TBIWG) and has been developed in alignment with other international associations. However, these recommendations should be read in conjunction with relevant national, state or territory legislation and local requirements, which take precedence over the ACPSEM recommendations. It is hoped that the users of this and other ACPSEM recommendations will contribute to the development of future versions through the ROSG of the ACPSEM. This document serves as a guideline for calibration and quality assurance of equipment used for TBI in Australasia.

Constitutive relations in plasticity, damage and fracture mechanics based on a work property

International Nuclear Information System (INIS)

Marigo, J.J.

1989-01-01

This paper is devoted to restrictions imposed by a work property of Drucker-Iliushin's type on the general class of mechanical systems with an elastic range which contains plastic, damaged and cracked media. The analysis is purely mechanical and quasi-static. Starting from very weak assumptions relative to this constitutive class, we obtain a fundamental inequality which generalizes Hill's maximal work principle. So we can justify, for instance: the convexity of the elastic domain and the normality rule of the plastic strain rate in stress space for the infinitesimal and some finite plasticity theories, Griffith's criterion in brittle fracture mechanics, and we obtain some original results for elastic and elastic plastic damaged materials. It must be noted that the procedure is purely deductive, the assumptions are explicit and the results are implications

On Working Capacity Criteria for Screw-Roller Mechanisms

Directory of Open Access Journals (Sweden)

D. S. Blinov

2015-01-01

Full Text Available Today roller-screw mechanisms (RSM are the most prospective motion converters from rotary to linear type. RSM manufacturers have suggested their design in the way, similar to the rolling bearings, in static and dynamic load ratings. The latter means that during long operations the main criterion of the RSM working capacity is fatigue spalling. However, this approach does not permit to consider temporal changes of the most critical performance parameters of the RSM (such as the axial play, the efficiency factor, the axial stiffness, the accuracy, the starting torque force for zero lash RSMs, etc. through calculations. The abovementioned method was not perfect, because the choice of the main criterion of RSM working capacity was wrong. The article proves that wear-resistance is the main criterion of RSM working capacity. The proof is the RSM efficiency factor equal to 80-88% on the average. The power loss occurs because of overcoming a sliding friction between multiple (from 300 to 1000 interfacing turns of thread on the screw and the rollers as well as on the rollers and the nut. That is why the RSMs are the screwtype rolling mechanisms with an essential portion of sliding friction. High-accuracy measurements taken using the device called a form-tracer for threaded pieces permitted to determine the essential changes on the profiles of turns of threads on the rollers (a straight-line portion appeared on the radial profile; these changes could emerge only from wear. Besides, the length of this portion increased with the increasing RSM operation time. The JSC “Moskvich” has examined the RSMs, which have been put out of operation after completing their service life as parts of robot welding machines. There were no traces of fatigue spalling found on the threaded surfaces of the RSM parts, while the sizes of the straight-line portions on the turns of the roller threads were much bigger than they were during the measurements after the initial

[Night work, shift work: Breast cancer risk factor?].

Science.gov (United States)

Benabu, J-C; Stoll, F; Gonzalez, M; Mathelin, C

2015-12-01

The aim of this review was to determine the link between night/shift work and breast cancer. The analysed articles were taken from the PUBMED database between 1996 and 2015. The keywords used were "breast cancer risk", "night work" and "shift work". In total, 25 articles were selected. Night/shift workers are more at risk to develop a breast cancer (relative risk (RR) between 1.09; 95% CI: 1.02-1.20 and 1.48; 95% CI: 1.36-1.61 in the meta-analyses). However, this risk is not found by some cohort and case-control studies. The circadian rhythm disruption, responsible of disorderliness of melatonin secretion, could be one of the mechanisms involved in the increase of that risk. Hormonal status of night/shift workers, their geographic origin, their lifestyle and their vitamin D deficiency appear as other mechanisms potentially responsible for increased risk of cancer in this professional population. Moreover, a dose-effect connection may exist, with an increase of the risk with the number of years of night/shift work. Night/shift work is associated with a moderate increased risk of breast cancer, especially among women who worked over 20 years. Recommendations concerning the breast monitoring in this population could be diffused. The benefit of melatonin supplementation remains to be assessed. Copyright © 2015. Published by Elsevier SAS.

INTEGRATING DISTRIBUTED WORK: COMPARING TASK DESIGN, COMMUNICATION, AND TACIT COORDINATION MECHANISMS

DEFF Research Database (Denmark)

Srikanth, K.; Puranam, P.

2011-01-01

We investigate coordination strategies in integrating distributed work. In the context of Business Process Offshoring (BPO), we analyze survey data from 126 offshored processes to understand both the sources of difficulty in integrating distributed work as well as how organizations overcome...... on tacit coordination-and theoretically articulate and empirically show that tacit coordination mechanisms are distinct from the well-known duo of coordination strategies: building communication channels or modularizing processes to minimize the need for communication. We discuss implications for the study...

Patterns of mechanical energy change in tetrapod gait: pendula, springs and work.

Science.gov (United States)

Biewener, Andrew A

2006-11-01

Kinematic and center of mass (CoM) mechanical variables used to define terrestrial gaits are compared for various tetrapod species. Kinematic variables (limb phase, duty factor) provide important timing information regarding the neural control and limb coordination of various gaits. Whereas, mechanical variables (potential and kinetic energy relative phase, %Recovery, %Congruity) provide insight into the underlying mechanisms that minimize muscle work and the metabolic cost of locomotion, and also influence neural control strategies. Two basic mechanisms identified by Cavagna et al. (1977. Am J Physiol 233:R243-R261) are used broadly by various bipedal and quadrupedal species. During walking, animals exchange CoM potential energy (PE) with kinetic energy (KE) via an inverted pendulum mechanism to reduce muscle work. During the stance period of running (including trotting, hopping and galloping) gaits, animals convert PE and KE into elastic strain energy in spring elements of the limbs and trunk and regain this energy later during limb support. The bouncing motion of the body on the support limb(s) is well represented by a simple mass-spring system. Limb spring compliance allows the storage and return of elastic energy to reduce muscle work. These two distinct patterns of CoM mechanical energy exchange are fairly well correlated with kinematic distinctions of limb movement patterns associated with gait change. However, in some cases such correlations can be misleading. When running (or trotting) at low speeds many animals lack an aerial period and have limb duty factors that exceed 0.5. Rather than interpreting this as a change of gait, the underlying mechanics of the body's CoM motion indicate no fundamental change in limb movement pattern or CoM dynamics has occurred. Nevertheless, the idealized, distinctive patterns of CoM energy fluctuation predicted by an inverted pendulum for walking and a bouncing mass spring for running are often not clear cut, especially

[Total artificial heart].

Science.gov (United States)

Antretter, H; Dumfarth, J; Höfer, D

2015-09-01

To date the CardioWest™ total artificial heart is the only clinically available implantable biventricular mechanical replacement for irreversible cardiac failure. This article presents the indications, contraindications, implantation procedere and postoperative treatment. In addition to a overview of the applications of the total artificial heart this article gives a brief presentation of the two patients treated in our department with the CardioWest™. The clinical course, postoperative rehabilitation, device-related complications and control mechanisms are presented. The total artificial heart is a reliable implant for treating critically ill patients with irreversible cardiogenic shock. A bridge to transplantation is feasible with excellent results.

Redesigning the work system of rubber industries based on total ergonomics and ergo-micmac integration

Science.gov (United States)

Setiawan, H.

2018-01-01

The factory capacity achievement and the bottleneck reduction of production process at wet-blanket workstations are influenced by the balance of life quality rates and worker’s productivity, along with the worker’s ability and limitations, tasks, organization and work environment. The life quality of workers is indicated by: the reduction of workload, and fatigue. Meanwhile, work productivity is measured by increasing production results per work shift. The optimization of the quality of life and productivity of workers is achieved by redesigning the system and workstations based on ergonomics integrating Total Ergonomics with Ergo-MicMac (Micro Ergonomics and Macro Ergonomics), which includes redesigning wet-blanket folding worktable, regulating the system pattern of working in pairs, giving official break time, giving extra nutritious intakes such as sweet tea and snack Pempek, giving personal protective equipments, and redesigning physical working environments.This study was an experimental study, with treatment by subject design involving 30 workers sampled at a workstation condition before and after Ergonomics based redesign. The findings and conclusions of the study were derived from the reduction of the workload by 16.06%, fatigue by 18.84% and the increase of production results per work shift by 20.29%.

Order information coding in working memory: Review of behavioural studies and cognitive mechanisms

Directory of Open Access Journals (Sweden)

Barbara Dolenc

2014-06-01

Full Text Available Executive processes, such as coding for sequential order, are of extreme importance for higher-order cognitive tasks. One of the significant questions is, how order information is coded in working memory and what cognitive mechanisms and processes mediate it. The aim of this review paper is to summarize results of studies that explore whether order and item memory are two separable processes. Furthermore, we reviewed evidence for each of the proposed cognitive mechanism that might mediate order processing. Previous behavioural and neuroimaging data suggest different representation and processing of item and order information in working memory. Both information are maintained and recalled separately and this separation seems to hold for recognition as well as for recall. To explain the result of studies of order coding, numerous cognitive mechanisms were proposed. We focused on four different mechanisms by which order information might be coded and retrieved, namely inter-item associations, direct coding, hierarchical coding and magnitude coding. Each of the mechanisms can explain some of the aspect of order information coding, however none of them is able to explain all of the empirical findings. Due to its complex nature it is not surprising that a single mechanism has difficulties accounting for all the behavioral data and order memory may be more accurately characterized as the result of a set of mechanisms rather than a single one. Moreover, the findings beget a question of whether different types of memory for order information might exist.

A Neural Mechanism for Surprise-related Interruptions of Visuospatial Working Memory.

Science.gov (United States)

Wessel, Jan R

2018-01-01

Surprising perceptual events recruit a fronto-basal ganglia mechanism for inhibition, which suppresses motor activity following surprise. A recent study found that this inhibitory mechanism also disrupts the maintenance of verbal working memory (WM) after surprising tones. However, it is unclear whether this same mechanism also relates to surprise-related interruptions of non-verbal WM. We tested this hypothesis using a change-detection task, in which surprising tones impaired visuospatial WM. Participants also performed a stop-signal task (SST). We used independent component analysis and single-trial scalp-electroencephalogram to test whether the same inhibitory mechanism that reflects motor inhibition in the SST relates to surprise-related visuospatial WM decrements, as was the case for verbal WM. As expected, surprising tones elicited activity of the inhibitory mechanism, and this activity correlated strongly with the trial-by-trial level of surprise. However, unlike for verbal WM, the activity of this mechanism was unrelated to visuospatial WM accuracy. Instead, inhibition-independent activity that immediately succeeded the inhibitory mechanism was increased when visuospatial WM was disrupted. This shows that surprise-related interruptions of visuospatial WM are not effected by the same inhibitory mechanism that interrupts verbal WM, and instead provides evidence for a 2-stage model of distraction. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

An Overview of the Total Lightning Jump Algorithm: Past, Present and Future Work

Science.gov (United States)

Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.; Deierling, Wiebke; Kessinger, Cathy

2011-01-01

Rapid increases in total lightning prior to the onset of severe and hazardous weather have been observed for several decades. These rapid increases are known as lightning jumps and can precede the occurrence of severe weather by tens of minutes. Over the past decade, a significant effort has been made to quantify lightning jump behavior in relation to its utility as a predictor of severe and hazardous weather. Based on a study of 34 thunderstorms that occurred in the Tennessee Valley, early work conducted in our group at Huntsville determined that it was indeed possible to create a reasonable operational lightning jump algorithm (LJA) based on a statistical framework relying on the variance behavior of the lightning trending signal. We the expanded this framework and tested several variance-related LJA configurations on a much larger sample of 87 severe and non severe thunderstorms. This study determined that a configuration named the "2(sigma)" algorithm had the most promise in development of the operational LJA with a probability of detection (POD) of 87%, a false alarm rate (FAR) of 33%, a Heidke Skill Score (HSS) of 0.75. The 2(sigma) algorithm was then tested on an even larger sample of 711 thunderstorms of all types from four regions of the country where total lightning measurement capability existed. The result was very encouraging.Despite the larger number of storms and the inclusion of different regions of the country, the POD remained high (79%), the FAR was low (36%) and HSS was solid (0.71). Average lead time from jump to severe weather occurrence was 20.65 minutes, with a standard deviation of +/- 15 minutes. Also, trends in total lightning were compared to cloud to ground (CG) lightning trends, and it was determined that total lightning trends had a higher POD (79% vs 66%), lower FAR (36% vs 54 %) and a better HSS (0.71 vs 0.55). From the 711-storm case study it was determined that a majority of missed events were due to severe weather producing

How to Transform Mechanical Work into Electrical Energy Using a Capacitor

Science.gov (United States)

Skumiel, A.

2011-01-01

In this paper the method of converting mechanical work into electrical energy with the participation of a preliminarily charged condenser while the electrodes are sliding in it is presented. Using this method, we can obtain a considerable increase of converted electrical power, depending on the initial energy of the charged condenser, distance…

Work-related back discomfort and associated factors among automotive maintenance mechanics in Eastern Nigeria: A cross sectional study.

Science.gov (United States)

Abaraogu, Ukachukwu Okoroafor; Ezema, Charles Ikechukwu; Igwe, S E; Egwuonwu, Afamefuna Victor; Okafor, Udoka Chris

2016-02-15

Back pain has been identified as a common cause of disability in the working population. Automotive mechanics habitually use awkward back posture in their course of manual activity and hence may be at risk of work-related back pain. To investigate the prevalence, pattern and severity of back pain among automotive maintenance mechanics, as well as the personal and job variables associated with or predicting occurrence of back pain. Using a cross-sectional design, information about self-reported back pain and the associated variables were collected among 684 randomly recruited automotive mechanics. Prevalence of back pain was 76.02%; with the majority experiencing low back pain. 63.3% of the workers reported they limited their activity due to the back pain. Older workers (>50 years), daily work lasting ≥5 hours duration, no more than primary education, being normal weight, frequent use of kneeling and sustained postures, and lack of knowledge of ergonomic postures were associated with increased prevalence of back pain. Lack of job autonomy, inadequate task clarity, heavy physical work load, manual material handling, strenuous posture, noisy environment, vibrations, work schedule and inadequate auxiliary support were also associated with increased prevalence of back pain among the mechanics. Work-related back pain is prevalent among automotive maintenance mechanics. Work-related back pain is high among automotive maintenance mechanics. Workstation policy and legislation on reduction of risks with combined health literacy and ergonomic education programs in this occupational group are imperative.

Bidding for the unemployed: an application of mechanism design to welfare-to-work programs

NARCIS (Netherlands)

Onderstal, S.

2009-01-01

This paper applies the theory of mechanism design to welfare-to-work programs. When procuring welfare-to-work projects to employment service providers, governments face the problems of adverse selection (the winning provider is not the most efficient one) and moral hazard (the winning provider

Bidding for the unemployed: an application of mechanism design to welfare-to-work programs

NARCIS (Netherlands)

Onderstal, S.

2007-01-01

This paper applies the theory of mechanism design to welfare-to-work programs. When procuring welfare-to-work projects to employment service providers, governments face the problems of adverse selection (the winning provider is not the most efficient one) and moral hazard (the winning provider

On the role of fibril mechanics in the work of separation of fibrillating interfaces

NARCIS (Netherlands)

Vossen, B.G.; Sluis, van der O.; Schreurs, P.J.G.; Geers, M.G.D.; Neggers, J.; Hoefnagels, J.P.M.

2015-01-01

High values for the work of separation have been reported in peel tests on fibrillating interfacial systems. The exact origin of these high values is not properly understood, since it remains unclear which dissipative mechanisms related to fibrillation cause a significant increase in the work of

The effect of thermo-mechanical processing on the mechanical properties of molybdenum - 2 volume % lanthana

International Nuclear Information System (INIS)

Mueller, A.J.; Shields, J.A. Jr.; Buckman, R.W. Jr.

2001-01-01

Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 volume % La 2 O 3 mill product forms, produced by CSM Industries by a wet doping process, were characterized over the temperature range of -150 o C to 1800 o C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved .material had superior creep rupture properties to recrystallized material at 1200 o C, while at 1500 o C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % La 2 O 3 to the demands of the application being considered. (author)

Mechanical spectroscopy, internal friction and ultrasonic attenuation: Collection of works

International Nuclear Information System (INIS)

Magalas, L.B.

2009-01-01

An extensive collection of recommended books and proceedings from numerous conferences on internal friction, mechanical spectroscopy, and ultrasonic attenuation is provided. Reflecting the complicated history of the 20th century, books published in English and in Russian are presented in two separate sections. International and national conferences organized in various countries are listed. Supplementary lists referring to conferences held in the People's Republic of China, Poland, Russia, the Soviet Union, and Ukraine are also provided. The interesting evolution of mechanical spectroscopy from internal friction and ultrasonic attenuation in solids is clearly demonstrated, and a choice list of retrospective papers illustrates the evolution of the field. A brief review of mechanical spectroscopy, therefore, is included. Numerous research areas investigated by internal friction and mechanical spectroscopy are addressed, including point defect relaxations, electronic and phonon relaxations, dislocation relaxations, grain boundary relaxations, domain induced relaxations (magnetic, ferroelectric), magnetomechanical relaxations, phase transformations, glass transitions, interface effects as well as a wide array of applications specific to physics and materials science. For many years now, there has been a definite need to provide a thorough list of references that might cover major national conferences and books published in English and other languages. This work strives to achieve this goal.

WORKING MACHINE-HOUR COST COMPARISON OF MODERN ROAD COVERAGE PROCESSING MECHANIZATION

Directory of Open Access Journals (Sweden)

Dilyara Kyazymovna Izmaylova

2017-09-01

Full Text Available In the article there are mentioned features of alternative mechanization machine-hour cost calculations. Also determined analytical dependencies of calculating the expenses of ownership and maintenance. Given a comparison of expense items of various options for the processing implementation. The analysis is based on the international organizing experience for these types of work.

Attending work or not when sick – what makes the decision? A qualitative study among car mechanics

Directory of Open Access Journals (Sweden)

Morken Tone

2012-09-01

Full Text Available Abstract Background High prevalence of sickness absence in countries with generous welfare schemes has generated debates on mechanisms that may influence workers’ decisions about calling in sick for work. Little is known about the themes at stake during the decision-making process for reaching the choice of absence or attendance when feeling ill. The aim of the study was to examine decisions of absence versus attendance among car mechanics when feeling ill. Methods Interviews with 263 male car mechanics from 19 companies were used for the study, analysed by systematic text condensation and presented as descriptions and quotations of experiences and opinions. Results Three major themes were at stake during the decision-making process: 1 Experienced degree of illness, focusing on the present health condition and indicators of whether you are fit for work or not; 2 daily life habits, where attending work was a daily routine, often learned from childhood; 3 the importance of the job, with focus on the importance of work, colleagues, customers and work environment. Conclusions The car mechanics expressed a strong will to attend work in spite of illness. Knowledge about attitudes and dilemmas in reaching the decision regarding sickness absence or sickness attendance is useful in the prevention of sickness absence.

ACPSEM ROSG TBE working group recommendations for quality assurance in total body electron irradiation

International Nuclear Information System (INIS)

Nelligan, Raelene; Baldwin, Zoe; Ostwald, Trish; Tran, Thi; Bailey, Michael

2015-01-01

The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) Radiation Oncology Specialty Group (ROSG) formed a series of working groups in 2011 to develop recommendations for guidance of radiation oncology medical physics practice within the Australasian setting. These recommendations are intended to provide guidance for safe work practices and a suitable level of quality control without detailed work instructions. It is the responsibility of the medical physicist to ensure that locally available equipment and procedures are sufficiently sensitive to establish compliance to these recommendations. The recommendations are endorsed by the ROSG, and have been subject to independent expert reviews. For the Australian readers, these recommendations should be read in conjunction with the Tripartite Radiation Oncology Reform Implementation Committee Quality Working Group: Radiation Oncology Practice Standards (2011), and Radiation Oncology Practice Standards Supplementary Guide (2011). This publication presents the recommendations of the ACPSEM ROSG Total Body Electron Irradiation Working Group and has been developed in alignment with other international associations. However, these recommendations should be read in conjunction with relevant national, state or territory legislation and local requirements, which take precedence over the ACPSEM recommendations. It is hoped that the users of this and other ACPSEM recommendations will contribute to the development of future versions through the Radiation Oncology Specialty Group of the ACPSEM. This document serves as a guideline for calibration and quality assurance of equipment used for TBE in Australasia.

Total Participation Management: Toward Psychological Determinants of Subjective Well-Being at Work

Directory of Open Access Journals (Sweden)

Katarzyna Mika

2013-01-01

Full Text Available Aiming to determine which management practice has the strongest influence on the subjective well-being (SWB of employees, three workplaces were assessed with reference to different levels of total participation management (TPM, an innovative approach to human resource management. The study examined whether the level of TPM is positively related with SWB, defined according to Diener’s (1984 affective and cognitive facets of work. The psychological explanation of the predicted dependence was the level of satisfaction of three basic needs (autonomy, competence and relatedness distinguished by Deci and Ryan (2000a. The hypothesis about a positive relationship between SWB and TPM was confirmed. Results indicate that the least participative company has employees with the lowest subjective well-being and with the lowest satisfaction of basic psychological needs.

Early failure mechanisms of constrained tripolar acetabular sockets used in revision total hip arthroplasty.

Science.gov (United States)

Cooke, Christopher C; Hozack, William; Lavernia, Carlos; Sharkey, Peter; Shastri, Shani; Rothman, Richard H

2003-10-01

Fifty-eight patients received an Osteonics constrained acetabular implant for recurrent instability (46), girdlestone reimplant (8), correction of leg lengthening (3), and periprosthetic fracture (1). The constrained liner was inserted into a cementless shell (49), cemented into a pre-existing cementless shell (6), cemented into a cage (2), and cemented directly into the acetabular bone (1). Eight patients (13.8%) required reoperation for failure of the constrained implant. Type I failure (bone-prosthesis interface) occurred in 3 cases. Two cementless shells became loose, and in 1 patient, the constrained liner was cemented into an acetabular cage, which then failed by pivoting laterally about the superior fixation screws. Type II failure (liner locking mechanism) occurred in 2 cases. Type III failure (femoral head locking mechanism) occurred in 3 patients. Seven of the 8 failures occurred in patients with recurrent instability. Constrained liners are an effective method for treatment during revision total hip arthroplasty but should be used in select cases only.

Mechanical behavior and essential work of fracture of starch-based blown films

Science.gov (United States)

Nottez, M.; Chaki, S.; Soulestin, J.; Lacrampe, M. F.; Krawczak, P.

2015-05-01

A fracture mechanics approach (Essential Work of Fracture, EWF) was applied to assess the toughness of novel partly starch-grafted polyolefin blown films, compared to that of a neat polyethylene reference. Tests were performed on double-end notched samples. The digital image correlation method was used to monitor the deformation field around the notch. Regular tensile and tear tests were also carried out. The specific essential work of fracture is a characteristic which is much more sensitive to materials structural modifications than the tensile or tear properties.

Work hardening and mechanical equation of state in some metals in monotonic loading

International Nuclear Information System (INIS)

Wire, G.L.; Ellis, F.V.; Li, C.Y.

The work hardening coefficients of Type 316 stainless steel, niobium, and 1100 aluminum alloy are measured in tensile tests. It is demonstrated experimentally that in the measured stress, plastic strain rate, and temperature range the work hardening coefficient depends only on stress and plastic strain rate. The significance of the experimental results is discussed in terms of the concept of the mechanical equation of state for plastic deformation. 13 figures

Current Total Knee Designs: Does Baseplate Roughness or Locking Mechanism Design Affect Polyethylene Backside Wear?

Science.gov (United States)

Sisko, Zachary W; Teeter, Matthew G; Lanting, Brent A; Howard, James L; McCalden, Richard W; Naudie, Douglas D; MacDonald, Steven J; Vasarhelyi, Edward M

2017-12-01

Tibial baseplate roughness and polyethylene-insert micromotion resulting from locking-mechanism loosening can lead to polyethylene backside wear in TKAs. However, many retrieval studies examining these variables have evaluated only older TKA implant designs. We used implant-retrieval analysis to examine if there were differences in: (1) backside damage scores, (2) backside damage modes, and (3) backside linear wear rates in five TKA implant designs owing to differing baseplate surface roughness and locking mechanisms. Additionally, we examined if (4) patient demographics influence backside damage and wear. Five TKA implant models (four modern and one historical design) were selected with different tibial baseplate and/or locking mechanism designs. Six tibial inserts retrieved at the time of revision from each TKA model were matched for time in vivo, age of the patient at TKA revision, BMI, sex, revision number, and revision reason. Each insert backside was analyzed for: (1) visual total damage score and (2) individual visual damage modes, both by two observers and with an intraclass correlation coefficient of 0.66 (95% CI, 0.39-0.92), and (3) linear wear rate measured by micro-CT. Median primary outcomes were compared among the five designs. For our given sample size among five groups we could detect with 80% power a 10-point difference in damage score and an 0.11-mm per year difference in wear rate. The polished tibial design with a partial peripheral capture locking mechanism and anterior constraint showed a lower total damage score compared with the nonpolished tibial design with only a complete peripheral-rim locking mechanism (median, 12.5; range, 9.5-18.0; 95% CI, 9.58-16.42 versus median, 22.3; range, 15.5-27.0; 95% CI, 17.5-26.5; p = 0.019). The polished baseplate with a tongue-in-groove locking mechanism showed more abrasions than the nonpolished baseplate with a peripheral-rim capture and antirotational island (median, 7.25; range, 0.5-8.0; 95% CI, 2

Take-Off Efficiency: Transformation of Mechanical Work Into Kinetic Energy During the Bosco Test

Directory of Open Access Journals (Sweden)

Jandova Sona

2017-09-01

Full Text Available Purpose. The aim of the study is to present a new method for determining the efficiency of take-off during a 60-s Bosco repeated vertical jump test. Method. The study involved 15 physical education students (age: 21.5 ± 2.4 years; height: 1.81 ± 0.08 m; mass: 76 ± 9 kg. The data were collected with the use of a pedobarographical system (Pedar-x; Novel, Munich, Germany. The statistical analysis utilized a simple linear regression model. Results. Owing to possible fatigue, flight time and flight height decreased. The average flight height was 0.260 ± 0.063 m, and the average contact time equalled 0.54 ± 0.16 s. The average anaerobic power values calculated for the 60-s work period had the mean value of 21.9 ± 6.7 W · kgBW-1; there was a statistically significant (p < 0.05 decrease in anaerobic power during the 60-s Bosco test. Conclusions. The efficiency of mechanical work was highest at the beginning of the test, reaching values of up to 50%. The efficiency of mechanical work conversion into mechanical energy seems to be an appropriate determinant of rising fatigue during the 60-s Bosco jumping test.

Total down to work for Chtokman's gas

International Nuclear Information System (INIS)

Labeyre, J.

2008-01-01

In the framework of the exploitation contract signed with Gazprom, Total group, partner of the project with StatoilHydro, has started the feasibility study for the huge Chtokman gas field in Russia (Barents sea). A definitive investment decision should be given within less a year. The pre-project phase started in summer 2008 but nothing has been decided yet. Russia has two big projects in competition: Chtokman and Kharasavey in Yamal province. Considering the extreme climate conditions and the technical challenges, Russia will need the experience of foreign partners. (J.S.)

Erwin Schroedinger and the rise of wave mechanics. I. Schroedinger's scientific work before the creation of wave mechanics

International Nuclear Information System (INIS)

Mehra, J.

1987-01-01

This paper, the first part of a three-part article, gives an account of Erwin Schroedinger's growing up and studies in Vienna, his scientific work--first in Vienna from 1911 to 1920, then in Zurich from 1920 to 1925--on the dielectric properties of matter, atmospheric electricity and radioactivity, general relativity, color theory and physiological optics, and on kinetic theory and statistical mechanics

Global and Local Mechanical Responses for Necking of Rectangular Bars Using Updated and Total Lagrangian Finite Element Formulations

Directory of Open Access Journals (Sweden)

Claudio A. Careglio

2016-01-01

Full Text Available In simulations of forged and stamping processes using the finite element method, load displacement paths and three-dimensional stress and strains states should be well and reliably represented. The simple tension test is a suitable and economical tool to calibrate constitutive equations with finite strains and plasticity for those simulations. A complex three-dimensional stress and strain states are developed when this test is done on rectangular bars and the necking phenomenon appears. In this work, global and local numerical results of the mechanical response of rectangular bars subjected to simple tension test obtained from two different finite element formulations are compared and discussed. To this end, Updated and Total Lagrangian formulations are used in order to get the three-dimensional stress and strain states. Geometric changes together with strain and stress distributions at the cross section where necking occurs are assessed. In particular, a detailed analysis of the effective plastic strain, stress components in axial and transverse directions and pressure, and deviatoric stress components is presented. Specific numerical results are also validated with experimental measurements comparing, in turn, the performance of the two numerical approaches used in this study.

BAG3 regulates total MAP1LC3B protein levels through a translational but not transcriptional mechanism.

Science.gov (United States)

Rodríguez, Andrea E; López-Crisosto, Camila; Peña-Oyarzún, Daniel; Salas, Daniela; Parra, Valentina; Quiroga, Clara; Morawe, Tobias; Chiong, Mario; Behl, Christian; Lavandero, Sergio

2016-01-01

Autophagy is mainly regulated by post-translational and lipid modifications of ATG proteins. In some scenarios, the induction of autophagy is accompanied by increased levels of certain ATG mRNAs such as MAP1LC3B/LC3B, ATG5 or ATG12. However, little is known about the regulation of ATG protein synthesis at the translational level. The cochaperone of the HSP70 system BAG3 (BCL2-associated athanogene 3) has been associated to LC3B lipidation through an unknown mechanism. In the present work, we studied how BAG3 controls autophagy in HeLa and HEK293 cells. Our results showed that BAG3 regulates the basal amount of total cellular LC3B protein by controlling its mRNA translation. This effect was apparently specific to LC3B because other ATG protein levels were not affected. BAG3 knockdown did not affect LC3B lipidation induced by nutrient deprivation or proteasome inhibition. We concluded that BAG3 maintains the basal amount of LC3B protein by controlling the translation of its mRNA in HeLa and HEK293 cells.

Tsallis non-extensive statistical mechanics in the ionospheric detrended total electron content during quiet and storm periods

Science.gov (United States)

Ogunsua, B. O.; Laoye, J. A.

2018-05-01

In this paper, the Tsallis non-extensive q-statistics in ionospheric dynamics was investigated using the total electron content (TEC) obtained from two Global Positioning System (GPS) receiver stations. This investigation was carried out considering the geomagnetically quiet and storm periods. The micro density variation of the ionospheric total electron content was extracted from the TEC data by method of detrending. The detrended total electron content, which represent the variation in the internal dynamics of the system was further analyzed using for non-extensive statistical mechanics using the q-Gaussian methods. Our results reveals that for all the analyzed data sets the Tsallis Gaussian probability distribution (q-Gaussian) with value q > 1 were obtained. It was observed that there is no distinct difference in pattern between the values of qquiet and qstorm. However the values of q varies with geophysical conditions and possibly with local dynamics for the two stations. Also observed are the asymmetric pattern of the q-Gaussian and a highly significant level of correlation for the q-index values obtained for the storm periods compared to the quiet periods between the two GPS receiver stations where the TEC was measured. The factors responsible for this variation can be mostly attributed to the varying mechanisms resulting in the self-reorganization of the system dynamics during the storm periods. The result shows the existence of long range correlation for both quiet and storm periods for the two stations.

The working mechanism of manual therapy in participants with chronic tension-type headache

NARCIS (Netherlands)

Castien, R.F.; Blankenstein, A.H.; van der Windt, D.; Heijmans, M.W.; Dekker, J.

2013-01-01

STUDY DESIGN: Prospective longitudinal study.OBJECTIVE: To explore the working mechanism of manual therapy, we investigated whether 3 cervical spine variables were mediators of the effect of manual therapy on headache frequency.BACKGROUND: Manual therapy has been shown to reduce headache frequency

Research on working property and early age mechanical property of self-compacting concrete used in steel-concrete structure

International Nuclear Information System (INIS)

Zhao Yongguang

2013-01-01

Background: Self-compacting concrete that has good working property is the prerequisite of steel-concrete structure. The early age mechanical property of self-compacting concrete is the important parameter when design steel-concrete structure. Purpose: This paper attempts to research the working property and early age mechanical property of self-compacting concrete. Methods: Test is used to research the working property and early age mechanical property of self-compacting concrete. Results: Self-compacting concrete that could meet the requirement of steel-concrete structure has been mixed and parameters of early age mechanical property of self-compacting concrete which is necessary for design of steel-concrete structure have been presented. Conclusions: Base on the results, this paper can guide the construction of self-compacting concrete in steel-concrete structure and the design and construction of steel-concrete structure. (author)

On several parameters of mechanized timbering for working faces

Energy Technology Data Exchange (ETDEWEB)

Klorik' yan, S Kh

1979-08-01

Opinion is expressed that the two basic parameters characterizing mechanical timbers, the specific force in ton-forces per square meter of the supported roof surface over the working area and the one-meter length of installed timbering, do not permit selection of the optimum type of timber for a roof of the corresponding class. Experience has demonstrated that the most precise parameter is specific strength of the timber in ton-forces per meter and the determined ratio of the strength of all posts in a section to spacing of the section along the longwall. Also an operating width not exceeding 0.4 meter should serve as a criterion for using timbers on unstable hanging walls. (In Russian)

The effect of cup outer sizes on the contact mechanics and cement fixation of cemented total hip replacements.

Science.gov (United States)

Hua, Xijin; Li, Junyan; Wang, Ling; Wilcox, Ruth; Fisher, John; Jin, Zhongmin

2015-10-01

One important loosening mechanism of the cemented total hip arthroplasty is the mechanical overload at the bone-cement interface and consequent failure of the cement fixation. Clinical studies have revealed that the outer diameter of the acetabular component is a key factor in influencing aseptic loosening of the hip arthroplasty. The aim of the present study was to investigate the influence of the cup outer diameter on the contact mechanics and cement fixation of a cemented total hip replacement (THR) with different wear penetration depths and under different cup inclination angles using finite element (FE) method. A three-dimensional FE model was developed based on a typical Charnley hip prosthesis. Two acetabular cup designs with outer diameters of 40 and 43 mm were modelled and the effect of cup outer diameter, penetration depth and cup inclination angle on the contact mechanics and cement fixation stresses in the cemented THR were studied. The results showed that for all penetration depths and cup inclination angles considered, the contact mechanics in terms of peak von Mises stress in the acetabular cup and peak contact pressure at the bearing surface for the two cup designs were similar (within 5%). However, the peak von Mises stress, the peak maximum principal stress and peak shear stress in the cement mantle at the bone-cement interface for the 43 mm diameter cup design were predicted to be lower compared to those for the 40 mm diameter cup design. The differences were predicted to be 15-19%, 15-22% and 18-20% respectively for different cup penetration depths and inclination angles, which compares to the clinical difference of aseptic loosening incidence of about 20% between the two cup designs. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Proceedings of the 20th meeting of the working group on fracture mechanisms

International Nuclear Information System (INIS)

1988-01-01

This volume contains 41 contributions presented at the 20th meeting of the working group on fracture mechanisms. The contributions dealt with the following topics: 1.) mechanical and test fundamentals of crack initiating corrosion processes; 2.) crack formation in water and seawater; 3.) crack formation in the process industry; 4.) hydrogen-induced crack formation; 5.) stress and crack corrosion of rustproof cast alloys; 6.) corrosion-induced crack formation at high temperatures; 7.) experimental and numerical studies on fracture behaviour. 30 contributions were separately integrated in the data base 'ENERGY'. (MM) [de

[Physiological mechanisms of the etiology of visual fatigue during work involving visual stress].

Science.gov (United States)

Korniushina, T A

2000-01-01

Physiological parameters of vision were studied in three professional groups (a total of 1204 subjects): microscope operators, subjects working with magnifying glasses, and computer users. General and specific features of visual system fatigue formation were identified. Because of complete (in microscope operators) or partial (in subjects working with magnifying glasses and display users) "deprivation" of accommodation, these subjects develop early presbyopia (at the age of 30-35 years). In microscope operators long strain of accommodation system leads to professional myopia, while display users develop pseudomyopia. The highest overstrain is observed after 4 years of work in microscope operators, after 5 years in magnifying glass users, and after 6 years in computer users.

Tribology and total hip joint replacement: current concepts in mechanical simulation.

Science.gov (United States)

Affatato, S; Spinelli, M; Zavalloni, M; Mazzega-Fabbro, C; Viceconti, M

2008-12-01

Interest in the rheology and effects of interacting surfaces is as ancient as man. This subject can be represented by a recently coined word: tribology. This term is derived from the Greek word "tribos" and means the "science of rubbing". Friction, lubrication, and wear mechanism in the common English language means the precise field of interest of tribology. Wear of total hip prosthesis is a significant clinical problem that involves, nowadays, a too high a number of patients. In order to acquire further knowledge on the tribological phenomena that involve hip prosthesis wear tests are conducted on employed materials to extend lifetime of orthopaedic implants. The most basic type of test device is the material wear machine, however, a more advanced one may more accurately reproduce some of the in vivo conditions. Typically, these apparatus are called simulators, and, while there is no absolute definition of a joint simulator, its description as a mechanical rig used to test a joint replacement, under conditions approximating those occurring in the human body, is acceptable. Simulator tests, moreover, can be used to conduct accelerated protocols that replicate/simulate particularly extreme conditions, thus establishing the limits of performance for the material. Simulators vary in their level of sophistication and the international literature reveals many interpretations of the design of machines used for joint replacement testing. This paper aims to review the current state of the art of the hip joint simulators worldwide. This is specified through a schematic overview by describing, in particular, constructive solutions adopted to reproduce in vivo conditions. An exhaustive commentary on the evolution and actually existing simulation standards is proposed by the authors. The need of a shared protocol among research laboratories all over the world could lead to a consensus conference.

Respiratory mechanics in infants with severe bronchiolitis on controlled mechanical ventilation.

Science.gov (United States)

Cruces, Pablo; González-Dambrauskas, Sebastián; Quilodrán, Julio; Valenzuela, Jorge; Martínez, Javier; Rivero, Natalia; Arias, Pablo; Díaz, Franco

2017-10-06

Analysis of respiratory mechanics during mechanical ventilation (MV) is able to estimate resistive, elastic and inertial components of the working pressure of the respiratory system. Our aim was to discriminate the components of the working pressure of the respiratory system in infants on MV with severe bronchiolitis admitted to two PICU's. Infants younger than 1 year old with acute respiratory failure caused by severe bronchiolitis underwent neuromuscular blockade, tracheal intubation and volume controlled MV. Shortly after intubation studies of pulmonary mechanics were performed using inspiratory and expiratory breath hold. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory (PIP), plateau (PPL) and total expiratory pressures (tPEEP) were measured. Inspiratory and expiratory resistances (RawI and RawE) and Time Constants (K TI and K TE ) were calculated. We included 16 patients, of median age 2.5 (1-5.8) months. Bronchiolitis due to respiratory syncytial virus was the main etiology (93.8%) and 31.3% had comorbidities. Measured respiratory pressures were PIP 29 (26-31), PPL 24 (20-26), tPEEP 9 [8-11] cmH2O. Elastic component of the working pressure was significantly higher than resistive and both higher than threshold (tPEEP - PEEP) (P mechanics of infants with severe bronchiolitis receiving MV shows that the elastic component of the working pressure of the respiratory system is the most important. The elastic and resistive components in conjunction with flow profile are characteristic of restrictive diseases. A better understanding of lung mechanics in this group of patients may lead to change the traditional ventilatory approach to severe bronchiolitis.

Applications of quantum mechanical techniques to areas outside of quantum mechanics

CERN Document Server

Khrennikov, Andrei

2018-01-01

This book deals with applications of quantum mechanical techniques to areas outside of quantum mechanics, so-called quantum-like modeling. Research in this area has grown over the last 15 years. But even already more than 50 years ago, the interaction between Physics Nobelist Pauli and the psychologist Carl Jung in the 1950's on seeking to find analogous uses of the complementarity principle from quantum mechanics in psychology needs noting. This book does NOT want to advance that society is quantum mechanical! The macroscopic world is manifestly not quantum mechanical. But this rules not out that one can use concepts and the mathematical apparatus from quantum physics in a macroscopic environment. A mainstay ingredient of quantum mechanics, is 'quantum probability' and this tool has been proven to be useful in the mathematical modelling of decision making. In the most basic experiment of quantum physics, the double slit experiment, it is known (from the works of A. Khrennikov) that the law of total probabi...

[Application of tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty].

Science.gov (United States)

Li, Guoliang; Han, Guangpu; Zhang, Jinxiu; Ma, Shiqiang; Guo, Donghui; Yuan, Fulu; Qi, Bingbing; Shen, Runbin

2013-07-01

To explore the application value of self-made tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty (TKA) for improving the lower extremity force line. Between January and August 2012, 13 cases (21 knees) of osteoarthritis with tibial extra-articular deformity were treated, including 5 males (8 knees) and 8 females (13 knees) with an average age of 66.5 years (range, 58-78 years). The disease duration was 2-5 years (mean, 3.5 years). The knee society score (KSS) was 45.5 +/- 15.5. Extra-articular deformities included 1 case of knee valgus (2 knees) and 12 cases of knee varus (19 knees). Preoperative full-length X-ray films of lower extremities showed 10-21 degrees valgus or varus deformity of tibial extra joint. Self-made tibial mechanical axis locator was used to determine and mark coronal tibial mechanical axis under X-ray before TKA, and then osteotomy was performed with extramedullary positioning device according to the mechanical axis marker.' All incisions healed by first intention, without related complications of infection and joint instability. All patients were followed up 5-12 months (mean, 8.3 months). The X-ray examination showed case of 2.9 degrees knee deviation angle at 3 days after operation, and the accurate rate was 95.2%. No loosening or instability of prosthesis occurred during follow-up. KSS score was 85.5 +/- 15.0 at last follow-up, showing significant difference when compared with preoperative score (t=12.82, P=0.00). The seft-made tibial mechanical axis locator can improve the accurate rate of the lower extremity force line in TKA for tibia extra-articular deformity.

Investigation of Microstructure and Mechanical Properties in Hot-work Tool Steels

OpenAIRE

Rey, Tomas

2017-01-01

Hot-work tool steels make up an important group of steels that are able to perform with good strength and toughness properties at elevated temperatures and stresses. They are able to gain this behavior through their alloy composition and heat treatment, which relies on the precipitation of alloy carbides to counter the loss in strength as the tempered material becomes more ductile. As demand grows for materials that are suitable for even harsher applications and that show improved mechanical ...

Work-hardening stages and deformation mechanism maps during tensile deformation of commercially pure titanium

DEFF Research Database (Denmark)

Becker, Hanka; Pantleon, Wolfgang

2013-01-01

Commercially pure titanium was tensile tested at different strain rates between 2.2×10−4s−1 and 6.7×10−1s−1 to characterize the strain rate dependence of plastic deformation and the dominating deformation mechanisms. From true stress-true plastic strain curves, three distinct work-hardening stages...... are identified. The work-hardening rate decreases linearly with increasing flow stress for all three stages and the work-hardening rate is the controlling factor for the transition between the different stages and mechanisms. During the initial stage (at lowest stresses) plastic deformation is carried mainly...... by dislocation slip, in the following stage (for moderate stresses), an abundance of 64.6∘〈1¯010〉 twin boundaries form indicating the dominance of {112¯2}〈1¯1¯23〉 compression twinning. During the last stage before the onset of necking, additional 84.8∘〈112¯0〉 twin boundaries are detected caused by {101...

The error in total error reduction.

Science.gov (United States)

Witnauer, James E; Urcelay, Gonzalo P; Miller, Ralph R

2014-02-01

Most models of human and animal learning assume that learning is proportional to the discrepancy between a delivered outcome and the outcome predicted by all cues present during that trial (i.e., total error across a stimulus compound). This total error reduction (TER) view has been implemented in connectionist and artificial neural network models to describe the conditions under which weights between units change. Electrophysiological work has revealed that the activity of dopamine neurons is correlated with the total error signal in models of reward learning. Similar neural mechanisms presumably support fear conditioning, human contingency learning, and other types of learning. Using a computational modeling approach, we compared several TER models of associative learning to an alternative model that rejects the TER assumption in favor of local error reduction (LER), which assumes that learning about each cue is proportional to the discrepancy between the delivered outcome and the outcome predicted by that specific cue on that trial. The LER model provided a better fit to the reviewed data than the TER models. Given the superiority of the LER model with the present data sets, acceptance of TER should be tempered. Copyright © 2013 Elsevier Inc. All rights reserved.

Correlates of occupational, leisure and total sitting time in working adults: results from the Singapore multi-ethnic cohort.

Science.gov (United States)

Uijtdewilligen, Léonie; Yin, Jason Dean-Chen; van der Ploeg, Hidde P; Müller-Riemenschneider, Falk

2017-12-13

Evidence on the health risks of sitting is accumulating. However, research identifying factors influencing sitting time in adults is limited, especially in Asian populations. This study aimed to identify socio-demographic and lifestyle correlates of occupational, leisure and total sitting time in a sample of Singapore working adults. Data were collected between 2004 and 2010 from participants of the Singapore Multi Ethnic Cohort (MEC). Medical exclusion criteria for cohort participation were cancer, heart disease, stroke, renal failure and serious mental illness. Participants who were not working over the past 12 months and without data on sitting time were excluded from the analyses. Multivariable regression analyses were used to examine cross-sectional associations of self-reported age, gender, ethnicity, marital status, education, smoking, caloric intake and moderate-to-vigorous leisure time physical activity (LTPA) with self-reported occupational, leisure and total sitting time. Correlates were also studied separately for Chinese, Malays and Indians. The final sample comprised 9384 participants (54.8% male): 50.5% were Chinese, 24.0% Malay, and 25.5% Indian. For the total sample, mean occupational sitting time was 2.71 h/day, mean leisure sitting time was 2.77 h/day and mean total sitting time was 5.48 h/day. Sitting time in all domains was highest among Chinese. Age, gender, education, and caloric intake were associated with higher occupational sitting time, while ethnicity, marital status and smoking were associated with lower occupational sitting time. Marital status, smoking, caloric intake and LTPA were associated with higher leisure sitting time, while age, gender and ethnicity were associated with lower leisure sitting time. Gender, marital status, education, caloric intake and LTPA were associated with higher total sitting time, while ethnicity was associated with lower total sitting time. Stratified analyses revealed different associations within

Vladimir I Arnold - Collected Works Representations of Functions, Celestial Mechanics, and KAM Theory 1957-1965

CERN Document Server

Arnold, Vladimir I; Khesin, Boris

2010-01-01

Vladimir Arnold is one of the great mathematical scientists of our time. He is famous for both the breadth and the depth of his work. At the same time he is one of the most prolific and outstanding mathematical authors. This first volume of his Collected Works focuses on representations of functions, celestial mechanics, and KAM theory.

[Hygienic characteristics of work conditions at large Hydroelectric Power Plants with mechanization and automatization].

Science.gov (United States)

Iakimova, L D

1997-01-01

The article touches upon hygienic problems associated with mechanization and automation of major hydroelectric power stations. The authors present criteria to evaluate work conditions of the main occupations participating in the technologic process of hydroelectric power stations.

Airway Complications of Total Artificial Heart.

Science.gov (United States)

Pathak, Vikas; Donovan, Colin; Malhotra, Rajiv

2017-02-01

The total artificial heart is the mechanical device which is used as a bridge to the heart transplant in patients with biventricular failure. Due to the mechanical nature of the device, patients receiving total artificial heart (TAH) require to be on anticoagulation therapy. Hemorrhage and coagulopathy are few of the known complications of TAH.

Hard Work in Soft Regulation: A Discussion of the Social Mechanisms in OHS Management Standards and Possible Dilemmas in the Regulation of Psychosocial Work Environment

Directory of Open Access Journals (Sweden)

Pernille Hohnen

2014-09-01

Full Text Available Certified occupational health and safety (OHS management systems have become a global instrument in regulation of the work environment. However, their actual impact on OHS—in particular on softer psychosocial issues in the work environment—has been questioned. The most important standard of OHS management is OHSAS 18001, which has recently been supplemented with a British publically available guideline (PAS 1010 focusing specifically on psychosocial risk management. On the basis of the international literature on management standards, the present paper analyses OHSAS 18001 and PAS 1010 in order to understand the mechanism by which they work. The paper takes a social constructionist approach conceptualizing standards and their expected mechanisms as socially constructed—based on a particular kind of knowledge and logic—although they are presented as objective. Such a constructionist approach also emphasizes how standards transform specific work environment problems into generic procedures that can be audited. In the case of OHS standards, both the work environment in general and the psychosocial risks in particular are transformed into simple monocausal auditable relations whereby the complexity of psychosocial work environment issues seems to disappear. The new PAS 1010 guideline, which is particularly focusing on regulation of the psychosocial work environment, only partly succeeds in solving these shortcomings of OHSAS 18001.

Scope of work for evaluating the mechanical performance of EPR first wall coatings

International Nuclear Information System (INIS)

Jones, W.B.; Van Den Avyle, J.A.

1978-01-01

An outline is presented for a proposed scope of work to evaluate the mechanical performance of candidate first wall coatings for a Tokamak-type fusion reactor. The goal of the overall program is to provide an adequate coating material and recoating process which can be manufactured by currently available vendors

Evidence for hydrogen-assisted recovery of cold-worked palladium: hydrogen solubility and mechanical properties studies

Directory of Open Access Journals (Sweden)

Maria Ferrer

2017-07-01

Full Text Available The influence of hydrogen as an agent to accelerate the thermal recovery of cold-worked palladium has been investigated. The techniques used to characterize the effects of hydrogen on the thermal recovery of palladium were hydrogen solubility and mechanical property measurements. Results show that the presence of modest amounts of hydrogen during annealing of cold-worked palladium does enhance the degree of thermal recovery, with a direct correlation between the amount of hydrogen during annealing and the degree of recovery. The results indicate that the damage resulting from cold-working palladium can be more effectively and efficiently reversed by suitable heat treatments in the presence of appropriate amounts of hydrogen, as compared to heat treatment in vacuum. The somewhat novel technique of using changes in the hydrogen solubility of palladium as an indicator of thermal recovery has been validated and complements the more traditional technique of mechanical property measurements.

Virtual powers and virtual works in mechanics of micropolar continuous media

International Nuclear Information System (INIS)

Grossetie, J.C.

1981-01-01

The expression of virtual work and virtual powers of internal actions is established for a continuous medium where the actions are defined by fields of forces and moments. A basic formulation of the mechanical problem is thus obtained and can serve as the starting point for variational and quasi-variational formulations of these problems. This expression may be used in thermodynamic developments relating to research or constitutive laws of materials within the context of so-called hidden internal variable formulations. The principle of virtual works is given in general applied then to the classic case through a demonstration consistent with this principle and finally applied to the general case in which distributions of moments are included. The viewpoint adopted is that Euler-Cauchy. This expression will have to be accounted for in establishing thermodynamic relations regarding materials subjected to nuclear effects (irradiated materials)

Total quality management - It works for aerospace information services

Science.gov (United States)

Erwin, James; Eberline, Carl; Colquitt, Wanda

1993-01-01

Today we are in the midst of information and 'total quality' revolutions. At the NASA STI Program's Center for AeroSpace Information (CASI), we are focused on using continuous improvements techniques to enrich today's services and products and to ensure that tomorrow's technology supports the TQM-based improvement of future STI program products and services. The Continuous Improvements Program at CASI is the foundation for Total Quality Management in products and services. The focus is customer-driven; its goal, to identify processes and procedures that can be improved and new technologies that can be integrated with the processes to gain efficiencies, provide effectiveness, and promote customer satisfaction. This Program seeks to establish quality through an iterative defect prevention approach that is based on the incorporation of standards and measurements into the processing cycle.

Work-related gender differences in physician-certified sick leave: a prospective study of the general working population in Norway.

Science.gov (United States)

Sterud, Tom

2014-07-01

This study aimed to examine gender differences in physician-certified sick leave and the extent to which these differences can be explained by work-related psychosocial and mechanical risk factors. Randomly drawn from the general population in Norway, the cohort comprised working men and women aged 18-69 years (N=12 255, response rate at baseline = 60.9%). Eligible respondents were interviewed in 2009 and registered with an active employee relationship of ≥ 100 actual working days in 2009 and 2010 (N=3688 men and 3070 women). The study measured 11 work-related psychosocial factors and 11 mechanical exposures, and outcomes of interest were physician-certified general sick leave (GSL) >0 days and long-term sick leave (LTSL) ≥ 40 working days during 2010. Women reported a significantly higher level of exposure to 9 of the 11 psychosocial factors evaluated. For mechanical factors, the reporting was mixed. After controlling for age, educational level, sick leave during 2009, housework, working hours and family status, a 1.7-fold risk for GSL and LTSL were found among women. In comparison with the initial model, adjusting for psychosocial factors reduced the excess risk by 21% and 27% for GSL and LTSL, respectively. The total effect of mechanical factors was negligible. Differences between occupations held by women and men explained an additional one-tenth of the excess risk for LTSL among women. Work-related psychosocial factors contributed significantly to a higher level of GSL and LTSL among women. The most important factors were demands for hiding emotions, emotional demands, and effort-payment imbalance.

Nursing work hours: individual needs versus working conditions.

Science.gov (United States)

Silva, Amanda Aparecida; Rotenberg, Lúcia; Fischer, Frida Marina

2011-12-01

To assess factors associated with professional and total hours of work (work + home) among nursing staff. Cross-sectional study conducted in a university hospital in the city of São Paulo, southeastern Brazil, between 2004 and 2005. A total of 696 workers (nurses, nurse technicians and aids), mostly women (87.8%) working day and/or night shifts, participated in the study. A self-administered questionnaire was used to collected information on demographic characteristics, and working and life conditions. Translated and adapted into Portuguese versions of the Job Stress Scale, Effort-reward imbalance, Short-Form-Health-related quality of life and the Work Ability Index were also administered. Logistic regression models were used for data analysis. Sole breadwinner, working night shifts and effort-reward imbalance were the variables associated with both professional (OR = 3.38, OR = 10.43, OR = 2.07, respectively) and total hours of work (OR = 1.57, OR = 3.37, OR = 2.75, respectively). There was no significant association between the variables related to hours of work and low Work Ability Index. Inadequate rest at home was statistically associated with professional (OR = 2.47) and total hours of work (OR = 1.48). Inadequate leisure time was significantly associated with professional hours of work (OR = 1.58) and barely associated with total hours of work (OR = 1.43). The sole breadwinner, working night shifts and effort-reward imbalance are variables that need to be further investigated in studies on work hours among nursing staff. These studies should explore workers' income and the relationship between effort and reward, taking into consideration gender issues.

Influences of lubricant pocket geometry and working conditions upon micro lubrication mechanisms in upsetting and strip drawing

DEFF Research Database (Denmark)

Shimizu, Ichiro; Martins, P. A. F.; Bay, Niels

2010-01-01

, during upsetting and strip drawing, by means of a rigid-viscoplastic finite-element formulation. Special emphasis is placed on the effect of pocket geometry on the build-up of hydrostatic pressure, which is responsible for the onset of micro-lubrication mechanisms. A good agreement is found between......Micro-lubricant pockets located in the surface of plastically deforming workpieces are recognised to improve the performance of fluid lubrication in a metal-forming process. This work investigates the joint influence of pocket geometry and process working conditions on micro-lubrication mechanisms...

Thermal creep effects on 20% cold worked AISI 316 mechanical properties

International Nuclear Information System (INIS)

Duncan, D.R.

1980-09-01

The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977 0 K and stresses of 86 MPa to 276 MPa. This resulted in strains up to 1.3%. Subsequent mechanical property tests included load change stress rupture tests (original test pressure increased or decreased), uniaxial tensile tests, and temperature ramp burst tests. Load change stress rupture tests were consistent with predictions from isobaric tests, and thus, consistent with the linear life fraction rule. Tests with large stress increases and tests at 866 0 K displayed a tendency for earlier than predicted failure. Tensile and temperature ramp burst tests had only slight effects on material properties (property changes were attributed to thermal recovery). The test results showed that, under the conditions of investigation, dislocation structure recovery was the most significant effect of creep. 9 figures, 5 tables

Qualità totale e mobilità totale Total Quality and Total Mobility

Directory of Open Access Journals (Sweden)

Giuseppe Trieste

2010-05-01

individual in its totality, with all its needs. For this reason it is necessary to focus on output of public and private transports which must be totally and globally accessible. Metropolitan and suburban transports need to have modern buses, and it has been calculated that it is possible to provide a total replacement of the fleet in a period from five to ten years. Total Quality must become the goal of every Local Government. FIABA suggests that a Total Quality Manager be always present in the institutional environment, as a guarantor of quality perceived by people living in their city for tourism, work, and leisure. It is essential to establish a favorable environment for all, to ensure the comfort of 100% of the population to give some definite and reliable answers.FIABA ONLUS (Italian Fund for Elimination of Architectural Barriers was founded in 2000 with the aim of promoting a culture of equal opportunities and, above all, it has as its main goal to involve public and private institutions to create a really accessible and usable environment for everyone. Total accessibility, Total usability and Total mobility are key indicators to define quality of life within cities. A supportive environment that is free of architectural, cultural and psychological barriers allows everyone to live with ease and universality. In fact, people who access to goods and services in the urban context can use to their advantage time and space, so they can do their activities and can maintain relationships that are deemed significant for their social life. The main aim of urban accessibility is to raise the comfort of space for citizens, eliminating all barriers that discriminate people, and prevent from an equality of opportunity. “FIABA FUND - City of ... for the removal of architectural barriers” is an idea of FIABA that has already affected many regions of Italy as Lazio, Lombardy, Campania, Abruzzi and Calabria. It is a National project which provides for opening a bank account in the

[Developmental changes in visuospatial working memory].

Science.gov (United States)

Oka, Makio; Takeuchi, Akihito; Morooka, Teruko; Ogino, Tatsuya; Ohtsuka, Yoko

2010-07-01

We investigated the developmental changes in visuospatial working memory using the Visuospatial Span Task (VST) and the Matrix Visuospatial Working Memory Test (VSWMT). VST is a short-term storage task, while VSWMT is a complex dual task. VSWMT requires the use of storage, processing, and selective attention, all of which are thought to be supported by the central executive (Baddeley). The subjects of this study were 60 typically developing children (43 boys and 17 girls) aged 6-14 years (average 10.4 years). For each task we evaluated span scores and the number of total passed trials, and investigated the changes that occurred with age. To further elucidate age-related changes in visuospatial working memory, we divided the subjects into three age groups (Group A: 6-8 years, Group B: 9-11 years, and Group C: 12-14 years of age), and statistically evaluated the differences between the groups. In both tasks, span scores and the number of total passed trials showed definite age-related changes from 6 to 14 years of age. Span scores and the number of total passed trials in VSMWT continued to increase until adolescence, with significant differences between the three age groups, while those in VST increased significantly between Groups A and B (the number of total passed trials only) and between Groups A and C (span scores and the number of total passed trials); there was no significant difference between Groups B and C, however. These results suggest that the network of the brain involved in visuospatial working memory gradually matures during early school years and adolescence, and that the basic mechanisms of this network exist by 6-7 years of age. Our results also show that VST and VSWMT are suitable tests for the evaluation of visuospatial working memory in childhood and adolescence.

Dissipation of mechanical work and temperature rise in AS4/PEEK thermoplastic composite

Science.gov (United States)

Georgiou, I.; Sun, C. T.

1990-01-01

The dissipated mechanical work per cycle of sinusoidal stress in the thermoplastic composite material AS4/PEEK was measured as a function of stress amplitude for fixed frequency and fiber orientation. The experimental result shows that the dissipated work per cycle is proportional to the square of the stress amplitude. Using the concept of the equivalent isotropic material, it is shown that the relaxation modulus satisfies a proportionality condition. Also, the rate of temperature rise due to sinusoidal stresses has been measured as a function of stress amplitude. The result shows that the rate of temperature rise is not proportional to the square of the stress amplitude.

How accurate is anatomic limb alignment in predicting mechanical limb alignment after total knee arthroplasty?

Science.gov (United States)

Lee, Seung Ah; Choi, Sang-Hee; Chang, Moon Jong

2015-10-27

Anatomic limb alignment often differs from mechanical limb alignment after total knee arthroplasty (TKA). We sought to assess the accuracy, specificity, and sensitivity for each of three commonly used ranges for anatomic limb alignment (3-9°, 5-10° and 2-10°) in predicting an acceptable range (neutral ± 3°) for mechanical limb alignment after TKA. We also assessed whether the accuracy of anatomic limb alignment was affected by anatomic variation. This retrospective study included 314 primary TKAs. The alignment of the limb was measured with both anatomic and mechanical methods of measurement. We also measured anatomic variation, including the femoral bowing angle, tibial bowing angle, and neck-shaft angle of the femur. All angles were measured on the same full-length standing anteroposterior radiographs. The accuracy, specificity, and sensitivity for each range of anatomic limb alignment were calculated and compared using mechanical limb alignment as the reference standard. The associations between the accuracy of anatomic limb alignment and anatomic variation were also determined. The range of 2-10° for anatomic limb alignment showed the highest accuracy, but it was only 73 % (3-9°, 65 %; 5-10°, 67 %). The specificity of the 2-10° range was 81 %, which was higher than that of the other ranges (3-9°, 69 %; 5-10°, 67 %). However, the sensitivity of the 2-10° range to predict varus malalignment was only 16 % (3-9°, 35 %; 5-10°, 68 %). In addition, the sensitivity of the 2-10° range to predict valgus malalignment was only 43 % (3-9°, 71 %; 5-10°, 43 %). The accuracy of anatomical limb alignment was lower for knees with greater femoral (odds ratio = 1.2) and tibial (odds ratio = 1.2) bowing. Anatomic limb alignment did not accurately predict mechanical limb alignment after TKA, and its accuracy was affected by anatomic variation. Thus, alignment after TKA should be assessed by measuring mechanical alignment rather than anatomic

MEASURING WORKING HOURS INPUT IN VINE GROWING AT WORK ORGANIZATION BASED ON PHENOLOGICAL PHASES

Directory of Open Access Journals (Sweden)

J BRAZSIL

2002-05-01

Full Text Available Research was based on phenological phases of Italian Riesling, involving differences in labour and financial input for dry, optimal and wet weather. Worktime demand for certain operations in vine growing was determined with an analytic method, work day survey and We worked out alternatives for dry, optimum and wet weather on the basis of phenological phaseses. The worktime demand for the phenological phases with all their operations were analysed and planned in an itemized way based on our findings. We used them to work out the worktime demand for the given vine land for each operation. To analyse differences coming from diverse methods of cultivation and spacing, the material, operational and total costs of hand and mechanized labour were projected for 1 hectare and variance analysis was made.

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension

DEFF Research Database (Denmark)

Sundstrup, Emil; Hansen, Åse Marie; Mortensen, Erik Lykke

2017-01-01

-regression analyses estimated the relative risk of register-based long-term sickness absence (LTSA) and disability pension with cumulative occupational mechanical exposures throughout working life. Analyses were censored for competing events and adjusted for multiple confounders. Results: During the follow-up period......Objectives: The aim of this study was to determine the prospective association of cumulative mechanical exposure during working life with health-related labor market outcomes. Methods: This prospective cohort study combines data from 5076 older workers (age 49-63 years) from the Copenhagen Aging...... from a JEM for ton-years (lifting 1000 kg each day in one year), lifting-years (lifting loads weighing ≥20 kg >10 times each day in one year), kneeling-years (kneeling for one hour each day in one year) and vibration-years (whole-body vibration for one hour each day in one year). Cox...

Cooperation mechanisms of the EU renewable energy directive and flexible mechanisms of the Kyoto Protocol: comparison and lessons learnt. Working paper

Energy Technology Data Exchange (ETDEWEB)

Frieden, Dorian; Tuerk, Andreas; Steiner, Daniel

2013-07-15

This working paper discusses similarities and differences between the cooperation mechanisms of the EU renewable energy directive (RES directive) and the flexible mechanisms of the Kyoto Protocol. The cooperation mechanisms allow the (virtual) trade of renewable energy and were introduced with the RES directive to provide Member States (MS) with greater flexibility to achieve their national targets for renewable energy sources (RES). A similar kind of flexibility is known from the flexible mechanisms of the Kyoto Protocol which aim at the cost efficient achievement of emission reduction targets. Lessons learned from the Kyoto mechanisms may allow conclusions to be drawn on the design and implementation of the renewable energy cooperation mechanisms. This paper first gives an overview of the cooperation mechanisms regarding their potential, advantages and disadvantages, barriers and preconditions. This is followed by a brief explanation of and a systematic comparison with the flexible mechanisms of the Kyoto Protocol – Joint Implementation (JI); Clean Development Mechanism (CDM); and International Emissions Trading (IET). A gamut of factors influenced the success of the Kyoto mechanisms in general and in specific national contexts. Therefore, it is not possible to directly transfer past experiences with the Kyoto mechanisms to the capability of specific nations to make use of the renewable energy cooperation mechanisms. A comparison of specific features, such as the mechanism type (transfer, project-based, support scheme), price building and specific barriers can, however, help anticipate the possible dynamics and challenges of the cooperation mechanisms. Experiences with the Kyoto mechanisms show that predictions based on supply-demand analysis were valid only to a limited extent and that specific factors such as institutional capacity constraints or legal uncertainties delayed or prevented the use of the mechanisms in some cases. Similarly, for the cooperation

Working Mechanism for Flexible Perovskite Solar Cells with Simplified Architecture.

Science.gov (United States)

Xu, Xiaobao; Chen, Qi; Hong, Ziruo; Zhou, Huanping; Liu, Zonghao; Chang, Wei-Hsuan; Sun, Pengyu; Chen, Huajun; De Marco, Nicholas; Wang, Mingkui; Yang, Yang

2015-10-14

In this communication, we report an efficient and flexible perovskite solar cell based on formamidinium lead trihalide (FAPbI3) with simplified configuration. The device achieved a champion efficiency of 12.70%, utilizing direct contact between metallic indium tin oxide (ITO) electrode and perovskite absorber. The underlying working mechanism is proposed subsequently, via a systematic investigation focusing on the heterojunction within this device. A significant charge storage has been observed in the perovskite, which is believed to generate photovoltage and serves as the driving force for charge transferring from the absorber to ITO electrode as well. More importantly, this simplified device structure on flexible substrates suggests its compatibility for scale-up fabrication, which paves the way for commercialization of perovskite photovoltaic technology.

High mechanical advantage design of six-bar Stephenson mechanism for servo mechanical presses

Directory of Open Access Journals (Sweden)

Jianguo Hu

2016-06-01

Full Text Available This article proposed a two-phase design scheme of Stephenson six-bar working mechanisms for servo mechanical presses with high mechanical advantage. In the qualitative design phase, first, a Stephenson six-bar mechanism with a slide was derived from Stephenson six-bar kinematic chains. Second, based on the instant center analysis method, the relationship between mechanical advantage and some special instant centers was founded, and accordingly a primary mechanism configuration with high mechanical advantage was designed qualitatively. Then, a parameterized prototype model was established, and the influences of design parameters toward slide kinematical characteristics were analyzed. In the quantitative design phase, a multi-objective optimization model, aiming at high mechanical advantage and dwelling characteristics, was built, and a case design was done to find optimal dimensions. Finally, simulations based on the software ADAMS were conducted to compare the transmission characteristics of the optimized working mechanism with that of slide-crank mechanism and symmetrical toggle mechanism, and an experimental press was made to validate the design scheme. The simulation and experiment results show that, compared with general working mechanisms, the Stephenson six-bar working mechanism has higher mechanical advantage and better dwelling characteristics, reducing capacities and costs of servo motors effectively.

Research concerning the balancing of a plane mechanism

Science.gov (United States)

Bădoiu, D.; Petrescu, M. G.; Antonescu, N. N.; Toma, G.

2018-01-01

By statically balancing of the plane mechanisms and especially those functioning at high speeds is being pursued the decrease of the value of the resultant force of all inertia forces that work on the component elements, thus obtaining a significant decrease in vibrations and shocks during the functioning. On the other hand, the existence of balancing masses which ensure the balancing of the mechanism leads to increased gauge and its mass. In this paper are presented some possibilities of statically balancing a plane mechanism which is composed of three independent contours. First is analyzed the case when the mechanism is totally balanced. Then a solution is proposed for a partial balancing of the mechanism based on the balancing of the first harmonic of the inertia force developed in a piston of the mechanism. Finally, are presented some simulation results concerning the variation of the value of the resultant inertia force during a cinematic cycle when the mechanism is unbalanced and when it is partially balanced. Also, it is analyzed the variation of the motor moment when the mechanism is unbalanced and when is totally and partially balanced.

Live to Work or Love to Work: Work Craving and Work Engagement

OpenAIRE

Wojdylo, Kamila; Baumann, Nicola; Fischbach, Lis; Engeser, Stefan

2014-01-01

OBJECTIVE: According to the theory of work craving, a workaholic has a craving for self-worth compensatory incentives and an expectation of relief from negative affect experienced through neurotic perfectionism and an obsessive-compulsive style of working. Research has shown that workaholism and work engagement should be considered as two distinct work styles with different health consequences. However, the mechanisms underlying the adoption of these work styles have been neglected. The prese...

Evolution of the Stability Work from Classic Retaining Walls to Mechanically Stabilized Earth Walls

Directory of Open Access Journals (Sweden)

Anghel Stanciu

2008-01-01

Full Text Available For the consolidation of soil mass and the construction of the stability works for roads infrastructure it was studied the evolution of these kinds of works from classical retaining walls - common concrete retaining walls, to the utilization in our days of the modern and competitive methods - mechanically stabilized earth walls. Like type of execution the variety of the reinforced soil is given by the utilization of different types of reinforcing inclusions (steel strips, geosynthetics, geogrids or facing (precast concrete panels, dry cast modular blocks, metal sheets and plates, gabions, and wrapped sheets of geosynthetics.

Work-Home Interference, Perceived Total Workload, and the Risk of Future Sickness Absence Due to Stress-Related Mental Diagnoses Among Women and Men: a Prospective Twin Study.

Science.gov (United States)

Svedberg, Pia; Mather, Lisa; Bergström, Gunnar; Lindfors, Petra; Blom, Victoria

2018-02-01

Work-home interference has been proposed as an important explanation for sickness absence (SA). Previous studies show mixed results, have not accounted for familial factors (genetics and shared everyday environment), or investigated diagnosis specific SA. The aim was to study whether work-home interference and perceived total workload predict SA due to stress-related mental diagnoses, or SA due to other mental diagnoses, among women and men, when adjusting for various confounders and familial factors. This study included 11,916 twins, 19-47 years (49% women). Data on work-to-home and home-to-work conflicts, perceived total workload, and relevant confounders were derived from a 2005 survey, and national register data on SA spells until 2013 were obtained. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Discordant twin pair design was applied to adjust for familial factors. Each one unit increase in work-to-home and home-to-work conflicts, and perceived total workload was associated with higher odds for SA due to stress-related mental diagnoses and to SA due to other mental diagnoses among women, when adjusting for sociodemographic factors (ORs 1.15-1.31). Including health or familial factors, no associations remained. For men, each one unit increase in work-to-home conflicts was associated with higher odds for SA due to stress-related diagnoses (ORs 1.23-1.35), independently of confounders. Work-to-home conflict was independently associated with future SA due to stress-related diagnoses among men only. Health- and work-related factors seem to be important confounders when researching work-home interference, perceived total workload, and SA. Not including such confounders involves risking drawing incorrect conclusions. Further studies are needed to confirm sex differences and whether genetic factors are important for the associations studied.

Total quality management: It works for aerospace information services

Science.gov (United States)

Erwin, James; Eberline, Carl; Colquitt, Wanda

1993-01-01

Today we are in the midst of information and 'total quality' revolutions. At the NASA STI Program's Center for AeroSpace Information (CASI), we are focused on using continuous improvements techniques to enrich today's services and products and to ensure that tomorrow's technology supports the TQM-based improvement of future STI program products and services. The Continuous Improvements Program at CASI is the foundation for Total Quality Management in products and services. The focus is customer-driven; its goal, to identify processes and procedures that can be improved and new technologies that can be integrated with the processes to gain efficiencies, provide effectiveness, and promote customer satisfaction. This Program seeks to establish quality through an iterative defect prevention approach that is based on the incorporation of standards and measurements into the processing cycle. Four projects are described that utilize cross-functional, problem-solving teams for identifying requirements and defining tasks and task standards, management participation, attention to critical processes, and measurable long-term goals. The implementation of these projects provides the customer with measurably improved access to information that is provided through several channels: the NASA STI Database, document requests for microfiche and hardcopy, and the Centralized Help Desk.

Recumbent vs. upright bicycles: 3D trajectory of body centre of mass, limb mechanical work, and operative range of propulsive muscles.

Science.gov (United States)

Telli, Riccardo; Seminati, Elena; Pavei, Gaspare; Minetti, Alberto Enrico

2017-03-01

Recumbent bicycles (RB) are high performance, human-powered vehicles. In comparison to normal/upright bicycles (NB) the RB may allow individuals to reach higher speeds due to aerodynamic advantages. The purpose of this investigation was to compare the non-aerodynamic factors that may potentially influence the performance of the two bicycles. 3D body centre of mass (BCoM) trajectory, its symmetries, and the components of the total mechanical work necessary to sustain cycling were assessed through 3D kinematics and computer simulations. Data collected at 50, 70, 90 110 rpm during stationary cycling were used to drive musculoskeletal modelling simulation and estimate muscle-tendon length. Results demonstrated that BCoM trajectory, confined in a 15-mm side cube, changed its orientation, maintaining a similar pattern across all cadences in both bicycles. RB displayed a reduced additional mechanical external power (16.1 ± 9.7 W on RB vs. 20.3 ± 8.8 W on NB), a greater symmetry on the progression axis, and no differences in the internal mechanical power compared to NB. Simulated muscle activity revealed small significant differences for only selected muscles. On the RB, quadriceps and gluteus demonstrated greater shortening, while biceps femoris, iliacus, and psoas exhibited greater stretch; however, aerodynamics still remains the principal benefit.

Mathematical Model and Algorithm for the Reefer Mechanic Scheduling Problem at Seaports

Directory of Open Access Journals (Sweden)

Jiantong Zhang

2017-01-01

Full Text Available With the development of seaborne logistics, the international trade of goods transported in refrigerated containers is growing fast. Refrigerated containers, also known as reefers, are used in transportation of temperature sensitive cargo, such as perishable fruits. This trend brings new challenges to terminal managers, that is, how to efficiently arrange mechanics to plug and unplug power for the reefers (i.e., tasks at yards. This work investigates the reefer mechanics scheduling problem at container ports. To minimize the sum of the total tardiness of all tasks and the total working distance of all mechanics, we formulate a mathematical model. For the resolution of this problem, we propose a DE algorithm which is combined with efficient heuristics, local search strategies, and parameter adaption scheme. The proposed algorithm is tested and validated through numerical experiments. Computational results demonstrate the effectiveness and efficiency of the proposed algorithm.

Schizophrenia and depression: A systematic review of the effectiveness and the working mechanisms behind acupuncture

NARCIS (Netherlands)

Bosch, M.P.C.; Noort, M.W.M.L. van den; Staudte, H.; Lim, S.

2015-01-01

OBJECTIVE: This systematic review assessed clinical evidence for the use of acupuncture as an add-on treatment in patients with depression and schizophrenia and for its underlying working mechanisms. DATA SOURCES: Four databases (Medline, Scopus, ERIC, and the Cochrane Library) were searched with a

The working mechanism of manual therapy in participants with chronic tension-type headache.

Science.gov (United States)

Castien, René; Blankenstein, Annette; van der Windt, Daniëlle; Heymans, Martijn W; Dekker, Joost

2013-10-01

Prospective longitudinal study. To explore the working mechanism of manual therapy, we investigated whether 3 cervical spine variables were mediators of the effect of manual therapy on headache frequency. Background Manual therapy has been shown to reduce headache frequency in participants with chronic tension-type headache (CTTH). To what extent specific elements of treatment contribute to the effectiveness of manual therapy in CTTH is unknown. One hundred eighty-two participants with CTTH participated in a prospective longitudinal study: 142 underwent manual therapy and 40 participants received usual care by their general practitioner. Regression analysis was performed according to the steps described by Baron and Kenny, and the proportion of mediated effect was estimated for 3 potential mediators: (1) cervical range of motion, (2) neck flexor endurance, and (3) forward head posture. Outcome was defined as a 50% or greater reduction in headache days. Neck flexor endurance mediated 24.5% of the effect of manual therapy. Cervical range of motion and forward head posture showed no mediated effect. Increased neck flexor endurance appears to be a working mechanism of manual therapy. This finding supports isometric training of neck flexors in participants with CTTH. Trial registered with Netherlands Trial Register (TR 1074).

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension: prospective cohort study.

Science.gov (United States)

Sundstrup, Emil; Hansen, Åse Marie; Mortensen, Erik Lykke; Poulsen, Otto Melchior; Clausen, Thomas; Rugulies, Reiner; Møller, Anne; Andersen, Lars L

2017-09-01

Objectives The aim of this study was to determine the prospective association of cumulative mechanical exposure during working life with health-related labor market outcomes. Methods This prospective cohort study combines data from 5076 older workers (age 49-63 years) from the Copenhagen Aging and Midlife Biobank with a job exposure matrix and a national register containing information on social transfer payment. By coding individual job histories from the Danish version of ISCO-codes (International Standard Classification of Occupations), we calculated cumulative occupational mechanical exposures from a JEM for ton-years (lifting 1000 kg each day in one year), lifting-years (lifting loads weighing ≥20 kg >10 times each day in one year), kneeling-years (kneeling for one hour each day in one year) and vibration-years (whole-body vibration for one hour each day in one year). Cox-regression analyses estimated the relative risk of register-based long-term sickness absence (LTSA) and disability pension with cumulative occupational mechanical exposures throughout working life. Analyses were censored for competing events and adjusted for multiple confounders. Results During the follow-up period, 970 persons (19.3%) had ≥1 episode of LTSA and 85 persons (1.7%) were granted a disability pension. Number of ton-, lifting- and kneeling-years showed an exposure-response association with increased risk of LTSA (Ppension (HR 1.75 95% CI 1.01-3.04). Conclusions Cumulative occupational mechanical exposures during working life - such as lifting and kneeling work - increased the risk of LTSA. Importantly, being exposed to lifting increased the risk of disability pension.

Hepatoprotective effect of peony total glucosides and the underlying mechanisms in diabetic rats.

Science.gov (United States)

Xia, Ling-Ling; Zhu, Qi-Jin; Wu, Yong-Gui

2017-12-01

Total glucosides of peony (TGP), compounds extracted from the dried roots of Paeonia lactiflora Pall, have been reported to have anti-inflammatory and antioxidative activities. However, the protective effect of TGP on liver injury and the underlying mechanisms remains unknown in diabetic rats. Current study investigates prevention of liver injury by TGP in diabetic rats and its mechanism was related to the inhibition of endoplasmic reticulum stress (ERS). Fifty adult male rats were randomly divided into: Normal group, diabetic group, TGP (50, 100 and 200 mg/kg/day) treatment groups (n = 10 per group). At the end of the 8th week, the liver was removed for biochemical and histological examinations. Compared with the diabetic group, administration of TGP at doses of 50, 100 and 200 mg/kg significantly prevented the increase of hepatic fibrosis score (ED 50 139.4 mg/kg). Compared with diabetic group, TGP at doses of 50, 100 and 200 mg/kg showed an inhibition on the increased macrophage infiltration. MCP-1 and TNF-α mRNA and protein expression were significantly increased in diabetic group compared with normal group; TGP administration caused significant reduction of high levels of MCP-1 and TNF-α mRNA as well as protein levels. Also, TGP at all doses showed an inhibition on the increased GRP78 levels, p-Perk levels and p-Eif2α levels in liver from diabetic group. Our results indicate that TGP has potential as a treatment for diabetic liver injury attenuating liver lipid accumulation and inflammation as well as ERS induced by diabetic condition.

Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

Science.gov (United States)

Donaldson, Finn E; Nyman, Edward; Coburn, James C

2015-07-16

Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation. Published by Elsevier Ltd.

Shift work and hypertension: Prevalence and analysis of disease pathways in a German car manufacturing company.

Science.gov (United States)

Ohlander, Johan; Keskin, Mekail-Cem; Stork, Joachim; Radon, Katja

2015-05-01

Hypertension and cardiovascular disease (CVD) may share a similar pathophysiology. Despite shift workers' CVD excess risk, studies on shift work and hypertension are inconclusive. Blood pressure and shift status for 25,343 autoworkers were obtained from medical check-ups and company registers. Cross-sectional associations modeling the total effect from shift work (day shifts, shift work without nights, rotating shift work with nights, and night shifts) on hypertension were assessed. By sequential adjustments, the influence of behavioral, psychosocial, and physiological factors on the total effect was examined, with subsequent mediation and moderation analyses. Adjusted for confounders, shift work without nights (vs. day shifts) was significantly associated with hypertension (OR 1.15, 95%CI 1.02-1.30). The total effect was mediated by BMI, physical inactivity, and sleep disorders. No moderation of the total effect by behaviors was found. The association between shift work and hypertension seems mainly attributable to behavioral mechanisms. © 2015 Wiley Periodicals, Inc.

Mechanical Energy Change in Inertial Reference Frames

Science.gov (United States)

Ghanbari, Saeed

2016-01-01

The mechanical energy change of a system in an inertial frame of reference equals work done by the total nonconservative force in the same frame. This relation is covariant under the Galilean transformations from inertial frame S to S', where S' moves with constant velocity relative to S. In the presence of nonconservative forces, such as normal…

The Dark Matter of Lab Work: Illuminating the Negotiation of Disciplined Perception in Mechanics

Science.gov (United States)

Lindwall, Oskar; Lymer, Gustav

2008-01-01

This study examines the practical work of a pair of students and an instructor using probeware in a mechanics lab. The aim of the study is to describe and discuss a type of interactional sequence that we refer to as "dark matter", the ordinary backdrop to the extraordinary sequences that are easily recognizable as clear-cut instances of learning.…

Photocatalytic degradation of paracetamol: intermediates and total reaction mechanism.

Science.gov (United States)

Moctezuma, Edgar; Leyva, Elisa; Aguilar, Claudia A; Luna, Raúl A; Montalvo, Carlos

2012-12-01

The advanced oxidation of paracetamol (PAM) promoted by TiO(2)/UV system in aqueous medium was investigated. Monitoring this reaction by HPLC and TOC, it was demonstrated that while oxidation of paracetamol is quite efficient under these conditions, its mineralization is not complete. HPLC indicated the formation of hydroquinone, benzoquinone, p-aminophenol and p-nitrophenol in the reaction mixtures. Further evidence of p-nitrophenol formation was obtained following the reaction by UV-vis spectroscopy. Continuous monitoring by IR spectroscopy demonstrated the breaking of the aromatic amide present in PAM and subsequent formation of several aromatic intermediate compounds such as p-aminophenol and p-nitrophenol. These aromatic compounds were eventually converted into trans-unsaturated carboxylic acids. Based on these experimental results, an alternative deacylation mechanism for the photocatalytic oxidation of paracetamol is proposed. Our studies also demonstrated IR spectroscopy to be a useful technique to investigate oxidative mechanisms of pharmaceutical compounds. Copyright © 2012 Elsevier B.V. All rights reserved.

The Mechanics of Mechanical Watches and Clocks

CERN Document Server

Du, Ruxu

2013-01-01

"The Mechanics of Mechanical Watches and Clocks" presents historical views and mathematical models of mechanical watches and clocks. Although now over six hundred years old, mechanical watches and clocks are still popular luxury items that fascinate many people around the world. However few have examined the theory of how they work as presented in this book. The illustrations and computer animations are unique and have never been published before. It will be of significant interest to researchers in mechanical engineering, watchmakers and clockmakers, as well as people who have an engineering background and are interested in mechanical watches and clocks. It will also inspire people in other fields of science and technology, such as mechanical engineering and electronics engineering, to advance their designs. Professor Ruxu Du works at the Chinese University of Hong Kong, China. Assistant Professor Longhan Xie works at the South China University of Technology, China.

Interagency registry for mechanically assisted circulatory support report on the total artificial heart.

Science.gov (United States)

Arabía, Francisco A; Cantor, Ryan S; Koehl, Devin A; Kasirajan, Vigneshwar; Gregoric, Igor; Moriguchi, Jaime D; Esmailian, Fardad; Ramzy, Danny; Chung, Joshua S; Czer, Lawrence S; Kobashigawa, Jon A; Smith, Richard G; Kirklin, James K

2018-04-26

We sought to better understand the patient population who receive a temporary total artificial heart (TAH) as bridge to transplant or as bridge to decision by evaluating data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database. We examined data related to survival, adverse events, and competing outcomes from patients who received TAHs between June 2006 and April 2017 and used hazard function analysis to explore risk factors for mortality. Data from 450 patients (87% men; mean age, 50 years) were available in the INTERMACS database. The 2 most common diagnoses were dilated cardiomyopathy (50%) and ischemic cardiomyopathy (20%). Risk factors for right heart failure were present in 82% of patients. Most patients were INTERMACS Profile 1 (43%) or 2 (37%) at implantation. There were 266 patients who eventually underwent transplantation, and 162 died. Overall 3-, 6-, and 12-month actuarial survival rates were 73%, 62%, and 53%, respectively. Risk factors for death included older age (p = 0.001), need for pre-implantation dialysis (p = 0.006), higher creatinine (p = 0.008) and lower albumin (p Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Use of Nonequilibrium Work Methods to Compute Free Energy Differences Between Molecular Mechanical and Quantum Mechanical Representations of Molecular Systems.

Science.gov (United States)

Hudson, Phillip S; Woodcock, H Lee; Boresch, Stefan

2015-12-03

Carrying out free energy simulations (FES) using quantum mechanical (QM) Hamiltonians remains an attractive, albeit elusive goal. Renewed efforts in this area have focused on using "indirect" thermodynamic cycles to connect "low level" simulation results to "high level" free energies. The main obstacle to computing converged free energy results between molecular mechanical (MM) and QM (ΔA(MM→QM)), as recently demonstrated by us and others, is differences in the so-called "stiff" degrees of freedom (e.g., bond stretching) between the respective energy surfaces. Herein, we demonstrate that this problem can be efficiently circumvented using nonequilibrium work (NEW) techniques, i.e., Jarzynski's and Crooks' equations. Initial applications of computing ΔA(NEW)(MM→QM), for blocked amino acids alanine and serine as well as to generate butane's potentials of mean force via the indirect QM/MM FES method, showed marked improvement over traditional FES approaches.

Motivation and Justice at Work: The Role of Emotion and Cognition Components of Personal and Collective Work Identity.

Science.gov (United States)

Nordhall, Ola; Knez, Igor

2017-01-01

The aim of this study was to investigate the role of personal and collective work identity (including emotion and cognition components), in predicting work motivation (operationalized as work self-determined motivation) and organizational justice (operationalized as organizational pay justice). Digitized questionnaires were distributed by e-mail to 2905 members, teachers, of a Swedish trade union. A total of 768 individuals answered the questionnaire and by that participated in this study. Personal- compared to collective work identity was shown to positively associate with self-determined motivation accounted for by the emotion component of personal work identity. Collective compared to personal work identity was reported to positively associate with organizational pay justice accounted for by the cognition component of collective work identity. All this suggests that both work-related motivation and organizational justice might be, to some extent, accounted for by the psychological mechanisms of work identity and that, as predicted, different types of work identity, play different significant roles in predicting motivation and justice at work. More precisely, the emotion component of work identity was more pronounced in personal work-bonding relationships, and the cognitive component, of work identity in contrast, was more pronounced in collective work-bonding relationships.

Working mechanisms of a behavioural intervention promoting physical activity in persons with subacute spinal cord injury

NARCIS (Netherlands)

Nooijen, Carla F. J.; Stam, Henk J.; Schoenmakers, Imte; Sluis, Tebbe; Post, Marcel; Twisk, Jos; van den Berg-Emons, Rita J. G.

OBJECTIVE: In order to unravel the working mechanisms that underlie the effectiveness of a behavioural intervention promoting physical activity in persons with subacute spinal cord injury, the aim of this study was to assess the mediating effects of physical and psychosocial factors on the

Dissociated time course between peak torque and total work recovery following bench press training in resistance trained men.

Science.gov (United States)

Ferreira, Diogo V; Gentil, Paulo; Ferreira-Junior, João B; Soares, Saulo R S; Brown, Lee E; Bottaro, Martim

2017-10-01

To evaluate the time course of peak torque and total work recovery after a resistance training session involving the bench press exercise. Repeated measures with a within subject design. Twenty-six resistance-trained men (age: 23.7±3.7years; height: 176.0±5.7cm; mass: 79.65±7.61kg) performed one session involving eight sets of the bench press exercise performed to momentary muscle failure with 2-min rest between sets. Shoulder horizontal adductors peak torque (PT), total work (TW), delayed onset muscle soreness (DOMS) and subjective physical fitness were measured pre, immediately post, 24, 48, 72 and 96h following exercise. The exercise protocol resulted in significant pectoralis major DOMS that lasted for 72h. Immediately after exercise, the reduction in shoulder horizontal adductors TW (25%) was greater than PT (17%). TW, as a percentage of baseline values, was also less than PT at 24, 48 and 96h after exercise. Additionally, PT returned to baseline at 96h, while TW did not. Resistance trained men presented dissimilar PT and TW recovery following free weight bench press exercise. This indicates that recovery of maximal voluntary contraction does not reflect the capability to perform multiple contractions. Strength and conditioning professionals should be cautious when evaluating muscle recovery by peak torque, since it can lead to the repetition of a training session sooner than recommended. Copyright © 2017. Published by Elsevier Inc.

An Overview of the Use of Mechanical Turk in Behavioral Sciences: Implications for Social Work

Science.gov (United States)

Chan, Chitat; Holosko, Michael J.

2016-01-01

Crowdsourcing is a process in which a firm parcels out work to a "crowd" and offers payment for anyone within the crowd who completes the task determined by that firm. A growing number of behavioral scientists have begun using the Mechanical Turk (MTurk) to facilitate their research and practice, but there is apparently not one academic…

Total cross sections for electron scattering with halocarbon molecules

Energy Technology Data Exchange (ETDEWEB)

Naghma, Rahla; Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

2014-03-01

Highlights: • A quantum mechanical model to find elastic, inelastic and total CS by e{sup −} impact. • Spherical complex optical potential formalism is used to find total CS. • Result shows consistency and good agreement with previous data wherever available. • Maiden attempt to find CS for CH{sub 2}Br{sub 2}, CHBr{sub 3}, CBr{sub 4} and C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules. • Interesting correlation observed between total CS and polarizability of the molecule. - Abstract: A theoretical study on electron collision with chlorinated methanes: CH{sub 2}Cl{sub 2} and CHCl{sub 3}, brominated methanes: CH{sub 2}Br{sub 2}, CHBr{sub 3} and CBr{sub 4} and some mono chloroalkanes: C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules in gaseous ground state is undertaken to report elastic, inelastic and total cross sections in the 20–5000 eV energy range. The target molecule is represented as a sum of various scattering centres, which are assumed to scatter electrons independently. The spherical complex optical potential (SCOP) is formulated to represent the interaction dynamics between the electron and the constituent scattering centres. Using SCOP, the quantum mechanical scattering problem is solved through partial wave analysis. The results obtained for CH{sub 2}Cl{sub 2} and CHCl{sub 3} are compared with the available experimental and theoretical values. The elastic cross section for CBr{sub 4} shows satisfactory agreement with the previous available data. The cross sections for CH{sub 2}Br{sub 2}, CHBr{sub 3}, and C{sub n}H{sub 2n+1}Cl (n = 2–4) molecules presented in this work are reported for the first time.

THE ANALYSIS OF TOTAL EXPENSES AT 1000 LEI TOTAL REVENUES AND OF THE RESULT OF THE GROWTH OF THEIR EFFICIENCY

Directory of Open Access Journals (Sweden)

LĂPĂDUŞI MIHAELA LOREDANA

2013-12-01

Full Text Available act The analysis of the company’s expenses is mainly important in the management and control activity, because it highlights the way in which are used the resources (material, human, financial and the impact of their allocation on the company’s performances. The optimization of the level of costs or the their reduction, where it is possible, without affecting the quality of the products and working conditions of the activity, represent the primary objectives of the management of companies.[9] Expenses have been and will remain one of the key indicators of a company requiring continuous application of a control and monitoring mechanism because when it comes to expenses we never speak of their growth, but their reduction. This reduction is the main objective of any economic agent that will result in increasing the efficiency of the entire activity. The costs of a company reflect in cash the total consumption of material, human and financial resources used in manufacturing and selling of the products. The level, dynamics and structure of these expenses reflect synthetically the activity of industrial enterprises when using effectively the available resources. The purpose of this article is to analyze synthetically a company's expenses efficiency based on the efficiency ratio of total expenses at 1000 lei total revenues and the purpose of the article results in a set of conclusions that will highlight a number of important issues concerning the role and the importance of the efficiency of total expenses related to total revenue, as well as the result of the growth of the efficiency of total expenses.

Different cortical mechanisms for spatial vs. feature-based attentional selection in visual working memory

Directory of Open Access Journals (Sweden)

Anna Heuer

2016-08-01

Full Text Available The limited capacity of visual working memory necessitates attentional mechanisms that selectively update and maintain only the most task-relevant content. Psychophysical experiments have shown that the retroactive selection of memory content can be based on visual properties such as location or shape, but the neural basis for such differential selection is unknown. For example, it is not known if there are different cortical modules specialized for spatial versus feature-based mnemonic attention, in the same way that has been demonstrated for attention to perceptual input. Here, we used transcranial magnetic stimulation (TMS to identify areas in human parietal and occipital cortex involved in the selection of objects from memory based on cues to their location (spatial information or their shape (featural information. We found that TMS over the supramarginal gyrus (SMG selectively facilitated spatial selection, whereas TMS over the lateral occipital cortex selectively enhanced feature-based selection for remembered objects in the contralateral visual field. Thus, different cortical regions are responsible for spatial vs. feature-based selection of working memory representations. Since the same regions are involved in attention to external events, these new findings indicate overlapping mechanisms for attentional control over perceptual input and mnemonic representations.

Do Work-Life Balance Policies Increase a Firm's Total Factor Productivity?: Evidence from panel data of Japanese firms (Japanese)

OpenAIRE

YAMAMOTO Isamu; MATSUURA Toshiyuki

2011-01-01

This paper examines how firms' policies for workers' work-life balance (WLB) affect total factor productivity (TFP) in the long run, by using panel data of Japanese firms from the 1990s. Although we observed a positive correlation between firms' WLB policies and their TFP, once controlling for unobserved firm heterogeneity, we found no causal relationship where WLB policies increase a firm's TFP in the long run. Under the following conditions, however, WLB policies would likely improve a firm...

Offshoring White-Collar Work: An Explorative Investigation of the Processes and Mechanisms in Two Danish Manufacturing Firms

DEFF Research Database (Denmark)

Slepniov, Dmitrij; Larsen, Marcus Møller; Wæhrens, Brian Vejrum

2010-01-01

of this paper is two folded: to explain why knowledge-intensive service work in manufacturing firms is increasingly subject to offshoring and to understand the effects of this process on integration mechanisms for the firms involved. The empirical part of the study is based on two qualitative case studies...... of Danish manufacturers, and on the basis of these, we first argue that the drivers of white-collar work offshoring in many respects are parallel to those of the earlier wave of blue-collar work offshoring. However, the existing offshoring and outsourcing frameworks do not necessarily adequately address....... By relating white-collar work offshoring to integration means companies instigate to manage it, we attempt to bridge the existing knowledge gaps and advance understanding of the process of white-collar work offshoring and its implications....

[Preparation of hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata and study on its in vitro release mechanism].

Science.gov (United States)

Xu, Fang-Fang; Shi, Wei; Zhang, Hui; Guo, Qing-Ming; Wang Zhen-Zhong; Bi, Yu-An; Wang, Zhi-Min; Xiao, Wei

2015-01-01

In this study, hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata were prepared and the in vitro release behavior were also evaluated. The optimal prescription was achieved by studying the main factor of the type and amount of hydroxypropyl methylcellulose (HPMC) using single factor test and evaluating through cumulative release of three lactones. No burst drug release from the obtained matrix tablets was observed. Drug release sustained to 14 h. The release mechanism of three lactones from A. paniculata was accessed by zero-order, first-order, Higuchi and Peppas equation. The release behavior of total lactones from A. paniculata was better agreed with Higuchi model and the drug release from the tablets was controlled by degradation of the matrix. The preparation of hydrophilic matrix sustained release tablets of total lactones from A. paniculata with good performance of drug release was simple.

Long working hours and overweight and obesity in working adults.

Science.gov (United States)

Kim, Byung-Mi; Lee, Bo-Eun; Park, Hye-Sook; Kim, Young-Ju; Suh, Young-Ju; Kim, Jeong-Youn; Shin, Ji-Young; Ha, Eun-Hee

2016-01-01

Previous studies have identified a link between gender and the various risk factors associated with obesity. We examined obesity risk factors in working adults to identify the effects of differences in body mass index (BMI) and percentage body fat (PBF) between women and men. A total of 1,120 adults agreed to participate in the study. Data from 711 participants, including 411 women and 300 men, were analyzed. Multiple logistic regression analysis was used to estimate the effects of risk factors on obesity and being overweight. In addition, the least-squares (LS) means of both BMI and PBF were estimated by analysis of covariance (ANCOVA) in a generalized linear model. Increases in BMI and PBF were significantly related to an age > 50 years and long working hours in women after compensating for confounding factors. Using the PBF criterion, the odds ratio (OR) of being overweight or obese in women > 50 years of age who worked for > 9 h a day was 3.9 (95% confidence interval [CI], 1.05-11.00). For BMI, women who were > 50 years of age and worked for > 9 h a day were 3.82 times (95% CI, 1.31-11.14) more likely to be overweight or obese than those who were worked for working adults was associated with > 50 years of age and long working hours in women. Further studies are needed to investigate the underlying mechanisms of this relationship and its potential implications for the prevention and management of excess weight and obesity.

Protective effects of total glucosides of paeony and the underlying mechanisms in carbon tetrachloride-induced experimental liver injury

Science.gov (United States)

Qin, Ying; Tian, Ya-ping

2011-01-01

Introduction We explored the protective effects of total glucosides of paeony (TGP) and the underlying mechanisms in carbon tetrachloride (CCl4)-induced experimental liver injury in mice. Material and methods Chronic liver damage was induced by intraperitoneal injection of CCl4 (0.5 µl/g) three times per week for 8 weeks. Mice also received 25, 50 or 100 mg/kg TGP. Liver sections were stained with haematoxylin/eosin. Serum amino transferases, lipid peroxidation and tumour necrosis factor-α (TNF-α) levels were determined using commercial assays. Quantitative real-time polymerase chain reaction was used to determine the changes in hepatic TNF-α, COX-2, iNOS and HO-1 expression. Protein levels of nitric oxide synthase, cyclooxygenase-2, haem oxygenase-1 and cytochrome P450 2E1 were determined by western blotting. Results Histological results showed that TGP improved the CCl4-induced changes in liver structure and alleviated lobular necrosis. The increases in serum protein and hepatic mRNA expression of TNF-α induced by CCl4 treatment were suppressed by TGP. Total glucosides of paeony also attenuated the increase the expression in iNOS and CYP2E1 but augmented the increase in HO-1.The mRNA and protein expression levels of inducible HO-1 increased significantly after CCl4 treatment. Conclusions Total glucosides of paeony protects hepatocytes from oxidative damage induced by CCl4. Total glucosides of paeony may achieve these effects by enhancing HO-1 expression and inhibiting the expression of proinflammatory mediators. PMID:22291795

Increasing energy efficiency level of building production based on applying modern mechanization facilities

Science.gov (United States)

Prokhorov, Sergey

2017-10-01

Building industry in a present day going through the hard times. Machine and mechanism exploitation cost, on a field of construction and installation works, takes a substantial part in total building construction expenses. There is a necessity to elaborate high efficient method, which allows not only to increase production, but also to reduce direct costs during machine fleet exploitation, and to increase its energy efficiency. In order to achieve the goal we plan to use modern methods of work production, hi-tech and energy saving machine tools and technologies, and use of optimal mechanization sets. As the optimization criteria there are exploitation prime cost and set efficiency. During actual task-solving process we made a conclusion, which shows that mechanization works, energy audit with production juxtaposition, prime prices and costs for energy resources allow to make complex machine fleet supply, improve ecological level and increase construction and installation work quality.

Psychological, social, and mechanical work exposures and disability retirement: a prospective registry study.

Science.gov (United States)

Emberland, Jan S; Nielsen, Morten Birkeland; Knardahl, Stein

2017-01-10

Relations between several occupational psychological and social factors and disability retirement remain largely unexplored. Knowledge of which specific aspects of the work environment that affect risk of disability is a prerequisite for the success of organizational interventions aiming to prevent premature work force exit. The objective of the present study was to determine contributions to registered disability retirement by a broad range of psychological and social work exposures while taking into account effects of mechanical exposure. Written consent was obtained from 13 012 employees (96 organizations) representing a wide range of occupations, to link their survey responses to data from the Norwegian national registry of disability compensation. Median follow-up time was 5.8 years. To determine effects of self-reported work exposures on risk of disability retirement hazard ratios (HR) and 99% confidence intervals (99% CI) were calculated with Cox regression analysis. Effects of sex, age group, skill level, sickness absence in the last three years, and work exposures estimated to be confounders were accounted for. Post hoc stratification by sex was conducted to explore if identified predictors affected risk of disability retirement differently in men compared to women. Contributors to higher risk of disability retirement were "role conflict" (high level HR 1.55 99% CI 1.07 to 2.24) and "physical workload" (high level HR 1.93 99% CI 1.39 to 2.68). Contributors to lower risk of disability retirement were "positive challenge" (high level HR 0.56 99% CI 0.34 to 0.93), "fair leadership" (high level HR 0.56 99% CI 0.39 to 0.81), and "control over work intensity" (high level HR 0.62, 99% CI 0.47 to 0.82). Direction of effects was not dependent on sex in any of the five identified predictors. Several specific psychological and social work factors are independent contributors to risk of disability retirement. In order to prevent premature work force exit workplace

Effects of high fluoride intake on child mental work capacity: preliminary investigation into the mechanisms involved

Energy Technology Data Exchange (ETDEWEB)

Li, Y.; Li, X.J.; Wei, S.Q. [Child & Adolescent Hygiene Teaching Research Station, Chengdu (China)

2008-10-15

A study was carried out on 157 children, age 12-13, from a coal-burning fluorosis endemic area together with an experiment looking into the effect of high fluoride intake in animals. The results showed that early, prolonged high fluoride intake causes a decrease in a child's mental work capacity and that prolonged high uptake of fluoride causes a child's levels of hair zinc to drop. A multifactoral correlative analysis demonstrated a direct correlation between hair zinc and mental work capacity. The decrease of 5-hydroxyindoleacetic acid and the increase of norepinephrine in animal brains exposed to high levels of fluoride suggest a possible mechanism for mental work capacity deficits in children. However, further research is necessary.

Rationalisation in public dental care – impact on clinical work tasks and mechanical exposure for dentists – a prospective study

DEFF Research Database (Denmark)

Jonker, D.; Rolander, B.; Balogh, I.

2013-01-01

. In the present prospective study we assessed mechanical exposures among Swedish dentists in relation to specific rationalisations of clinical dental work during a six-year period. Body postures and movements of 12 dentists were assessed by inclinometry synchronised to video recordings of their work...

Total Ambient Dose Equivalent Buildup Factor Determination for Nbs04 Concrete.

Science.gov (United States)

Duckic, Paulina; Hayes, Robert B

2018-06-01

Buildup factors are dimensionless multiplicative factors required by the point kernel method to account for scattered radiation through a shielding material. The accuracy of the point kernel method is strongly affected by the correspondence of analyzed parameters to experimental configurations, which is attempted to be simplified here. The point kernel method has not been found to have widespread practical use for neutron shielding calculations due to the complex neutron transport behavior through shielding materials (i.e. the variety of interaction mechanisms that neutrons may undergo while traversing the shield) as well as non-linear neutron total cross section energy dependence. In this work, total ambient dose buildup factors for NBS04 concrete are calculated in terms of neutron and secondary gamma ray transmission factors. The neutron and secondary gamma ray transmission factors are calculated using MCNP6™ code with updated cross sections. Both transmission factors and buildup factors are given in a tabulated form. Practical use of neutron transmission and buildup factors warrants rigorously calculated results with all associated uncertainties. In this work, sensitivity analysis of neutron transmission factors and total buildup factors with varying water content has been conducted. The analysis showed significant impact of varying water content in concrete on both neutron transmission factors and total buildup factors. Finally, support vector regression, a machine learning technique, has been engaged to make a model based on the calculated data for calculation of the buildup factors. The developed model can predict most of the data with 20% relative error.

Motivation and Justice at Work: The Role of Emotion and Cognition Components of Personal and Collective Work Identity

Directory of Open Access Journals (Sweden)

Ola Nordhall

2018-01-01

Full Text Available The aim of this study was to investigate the role of personal and collective work identity (including emotion and cognition components, in predicting work motivation (operationalized as work self-determined motivation and organizational justice (operationalized as organizational pay justice. Digitized questionnaires were distributed by e-mail to 2905 members, teachers, of a Swedish trade union. A total of 768 individuals answered the questionnaire and by that participated in this study. Personal- compared to collective work identity was shown to positively associate with self-determined motivation accounted for by the emotion component of personal work identity. Collective compared to personal work identity was reported to positively associate with organizational pay justice accounted for by the cognition component of collective work identity. All this suggests that both work-related motivation and organizational justice might be, to some extent, accounted for by the psychological mechanisms of work identity and that, as predicted, different types of work identity, play different significant roles in predicting motivation and justice at work. More precisely, the emotion component of work identity was more pronounced in personal work-bonding relationships, and the cognitive component, of work identity in contrast, was more pronounced in collective work-bonding relationships.

Motivation and Justice at Work: The Role of Emotion and Cognition Components of Personal and Collective Work Identity

Science.gov (United States)

Nordhall, Ola; Knez, Igor

2018-01-01

The aim of this study was to investigate the role of personal and collective work identity (including emotion and cognition components), in predicting work motivation (operationalized as work self-determined motivation) and organizational justice (operationalized as organizational pay justice). Digitized questionnaires were distributed by e-mail to 2905 members, teachers, of a Swedish trade union. A total of 768 individuals answered the questionnaire and by that participated in this study. Personal- compared to collective work identity was shown to positively associate with self-determined motivation accounted for by the emotion component of personal work identity. Collective compared to personal work identity was reported to positively associate with organizational pay justice accounted for by the cognition component of collective work identity. All this suggests that both work-related motivation and organizational justice might be, to some extent, accounted for by the psychological mechanisms of work identity and that, as predicted, different types of work identity, play different significant roles in predicting motivation and justice at work. More precisely, the emotion component of work identity was more pronounced in personal work-bonding relationships, and the cognitive component, of work identity in contrast, was more pronounced in collective work-bonding relationships. PMID:29379454

A mathematical model for the detection mechanism of DNA double-strand breaks depending on autophosphorylation of ATM.

Science.gov (United States)

Mouri, Kazunari; Nacher, Jose C; Akutsu, Tatsuya

2009-01-01

After IR stress, DNA double-strand breaks (DSBs) occur and repair proteins (RPs) bind to them, generating DSB-RP complexes (DSBCs), which results in repaired DSBs (RDSBs). In recent experimental studies, it is suggested that the ATM proteins detect these DNA lesions depending on the autophosphorylation of ATM which exists as a dimer before phosphorylation. Interestingly, the ATM proteins can work as a sensor for a small number of DSBs (approximately 18 DSBs in a cell after exposure to IR). Thus the ATM proteins amplify the small input signals based on the phosphorylation of the ATM dimer proteins. The true DSB-detection mechanism depending on ATM autophosphorylation has yet to be clarified. We propose a mathematical model for the detection mechanism of DSBs by ATM. Our model includes both a DSB-repair mechanism and an ATM-phosphorylation mechanism. We model the former mechanism as a stochastic process, and obtain theoretical mean values of DSBs and DSBCs. In the latter mechanism, it is known that ATM autophosphorylates itself, and we find that the autophosphorylation induces bifurcation of the phosphorylated ATM (ATM*). The bifurcation diagram depends on the total concentration of ATM, which makes three types of steady state diagrams of ATM*: monostable, reversible bistable, and irreversible bistable. Bistability exists depending on the Hill coefficient in the equation of ATM autophosphorylation, and it emerges as the total concentration of ATM increases. Combining these two mechanisms, we find that ATM* exhibits switch-like behaviour in the presence of bistability, and the detection time after DNA damage decreases when the total concentration of ATM increases. This work provides a mathematical model that explains the DSB-detection mechanism depending on ATM autophosphorylation. These results indicate that positive auto-regulation works both as a sensor and amplifier of small input signals.

Examining Structural Relationships between Work Engagement, Organizational Procedural Justice, Knowledge Sharing, and Innovative Work Behavior for Sustainable Organizations

Directory of Open Access Journals (Sweden)

Woocheol Kim

2017-02-01

Full Text Available Despite the importance of the human/social dimension of organizational sustainability, this area of scholastic endeavor has received relatively little attention when compared to the economic and environmental dimensions of sustainability. On the basis of social exchange theory, this study posited the important role that employee work engagement is a key component for improving human performance for organizational sustainability. In order to do so, it suggests the important role that employee work engagement has on the relationships among various factors in the organization, including organizational procedural justice, knowledge sharing, and innovative work behaviors. A total of 400 complete responses from full-time employees in Korean organizations were used for the purpose of data analysis with structural equation modeling (SEM. The results demonstrated that organizational procedural justice is positively related with employee work engagement, knowledge sharing, and innovative work behavior. In addition, work engagement enhances employee knowledge sharing and innovative work behavior, and knowledge sharing enhances innovative work behavior. With regard to the mechanisms of these relationships, work engagement and knowledge sharing acted as significant mediators. Based on the findings, we suggested relevant research implications and recommendations for future research on sustainable organizations.

Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

International Nuclear Information System (INIS)

Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt; Audouin, Laurent; Tassan-Got, Laurent; Aumann, Thomas; Casarejos, Enrique; Farget, Fanny; Rodriguez-Tajes, Carme; Heinz, Andreas; Jurado, Beatriz; Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut

2015-01-01

A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

Energy Technology Data Exchange (ETDEWEB)

Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric [CEA DAM Bruyeres-le-Chatel, Arpajon (France); Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, Laurent; Tassan-Got, Laurent [CNRS/IN2P3, IPNO, Orsay (France); Aumann, Thomas [Technische Universitaet Darmstadt, Darmstadt (Germany); Casarejos, Enrique [Universidad de Vigo, Vigo (Spain); Farget, Fanny; Rodriguez-Tajes, Carme [CNRS/IN2P3, GANIL, Caen (France); Heinz, Andreas [Chalmers University of Technology, Gothenburg (Sweden); Jurado, Beatriz [CNRS/IN2P3, CENBG, Gradignan (France); Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

2015-12-15

A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

Work-Family Conflict, Perceived Organizational Support and Professional Commitment: A Mediation Mechanism for Chinese Project Professionals.

Science.gov (United States)

Zheng, Junwei; Wu, Guangdong

2018-02-15

Projects are characterized by long working hours, complex tasks and being a kind of temporary organization. As such, work-family conflict is particularly prominent for project employees. This research examined whether and how work-family conflict affects professional commitment among Chinese project professionals. Research hypotheses were developed to explore the relationship between work-family conflict, professional commitment to the project and the mediating effects of perceived organizational support. Data were collected from 327 project managers or professionals working in construction enterprises in China; data were analyzed using structural equation modeling, applying the bootstrapping method. Results showed that there were three dimensions of work-family conflict: time-based conflict, strain-based conflict and behavior-based conflict. There were two dimensions of perceived organizational support: emotional support and instrumental support. The study also tested the negative effect of work-family conflict on professional commitment and the positive effect of perceived organizational support on professional commitment. Specifically, time-based conflict and emotional support had positive effects on professional commitment. Perceived organizational support had a total mediating effect between work-family conflict and professional commitment. The strain-based conflict dimension of work-family conflict had negative impacts on professional commitment through perceived emotional support and instrumental support. Overall, our findings extend a better understanding of work-family conflict and professional commitment in the project setting and verify the importance of social support in balancing work and family and improving employee mobility.

Work-Family Conflict, Perceived Organizational Support and Professional Commitment: A Mediation Mechanism for Chinese Project Professionals

Science.gov (United States)

2018-01-01

Projects are characterized by long working hours, complex tasks and being a kind of temporary organization. As such, work-family conflict is particularly prominent for project employees. This research examined whether and how work-family conflict affects professional commitment among Chinese project professionals. Research hypotheses were developed to explore the relationship between work-family conflict, professional commitment to the project and the mediating effects of perceived organizational support. Data were collected from 327 project managers or professionals working in construction enterprises in China; data were analyzed using structural equation modeling, applying the bootstrapping method. Results showed that there were three dimensions of work-family conflict: time-based conflict, strain-based conflict and behavior-based conflict. There were two dimensions of perceived organizational support: emotional support and instrumental support. The study also tested the negative effect of work-family conflict on professional commitment and the positive effect of perceived organizational support on professional commitment. Specifically, time-based conflict and emotional support had positive effects on professional commitment. Perceived organizational support had a total mediating effect between work-family conflict and professional commitment. The strain-based conflict dimension of work-family conflict had negative impacts on professional commitment through perceived emotional support and instrumental support. Overall, our findings extend a better understanding of work-family conflict and professional commitment in the project setting and verify the importance of social support in balancing work and family and improving employee mobility. PMID:29462860

Work-Family Conflict, Perceived Organizational Support and Professional Commitment: A Mediation Mechanism for Chinese Project Professionals

Directory of Open Access Journals (Sweden)

Junwei Zheng

2018-02-01

Full Text Available Projects are characterized by long working hours, complex tasks and being a kind of temporary organization. As such, work-family conflict is particularly prominent for project employees. This research examined whether and how work-family conflict affects professional commitment among Chinese project professionals. Research hypotheses were developed to explore the relationship between work-family conflict, professional commitment to the project and the mediating effects of perceived organizational support. Data were collected from 327 project managers or professionals working in construction enterprises in China; data were analyzed using structural equation modeling, applying the bootstrapping method. Results showed that there were three dimensions of work-family conflict: time-based conflict, strain-based conflict and behavior-based conflict. There were two dimensions of perceived organizational support: emotional support and instrumental support. The study also tested the negative effect of work-family conflict on professional commitment and the positive effect of perceived organizational support on professional commitment. Specifically, time-based conflict and emotional support had positive effects on professional commitment. Perceived organizational support had a total mediating effect between work-family conflict and professional commitment. The strain-based conflict dimension of work-family conflict had negative impacts on professional commitment through perceived emotional support and instrumental support. Overall, our findings extend a better understanding of work-family conflict and professional commitment in the project setting and verify the importance of social support in balancing work and family and improving employee mobility.

Cumulative occupational mechanical exposures during working life and risk of sickness absence and disability pension

DEFF Research Database (Denmark)

Sundstrup, Emil; Hansen, Åse Marie; Mortensen, Erik Lykke

2017-01-01

and Midlife Biobank with a job exposure matrix and a national register containing information on social transfer payment. By coding individual job histories from the Danish version of ISCO-codes (International Standard Classification of Occupations), we calculated cumulative occupational mechanical exposures......-regression analyses estimated the relative risk of register-based long-term sickness absence (LTSA) and disability pension with cumulative occupational mechanical exposures throughout working life. Analyses were censored for competing events and adjusted for multiple confounders. Results: During the follow-up period......, 970 persons (19.3%) had ≥1 episode of LTSA and 85 persons (1.7%) were granted a disability pension. Number of ton-, lifting- and kneeling-years showed an exposure-response association with increased risk of LTSA (P

Comparison of serum leptin, glucose, total cholesterol and total protein levels in fertile and repeat breeder cows

Directory of Open Access Journals (Sweden)

Saime Guzel

2014-12-01

Full Text Available In the present study we measured serum glucose, leptin, total cholesterol and total protein concentrations in repeat breeder cows and compared them with fertile cows. For this aim, 20 repeat breeder cows and 20 fertile cows were used as material. Repeat breeder cows were found to have lower levels of leptin and glucose as compared with fertile ones. No significant differences in total cholesterol and total protein levels were observed between the two groups. No significant correlation of leptin with glucose, total cholesterol and total protein was observed in fertile and repeat breeder cows. Low concentrations of glucose and leptin can have some effects on reproductive problems as repeat breeder and help to understand potential mechanisms impairing fertility in repeat breeder cows.

Mechanics without mechanisms

Science.gov (United States)

Eisenthal, Joshua

2018-05-01

At the time of Heinrich Hertz's premature death in 1894, he was regarded as one of the leading scientists of his generation. However, the posthumous publication of his treatise in the foundations of physics, Principles of Mechanics, presents a curious historical situation. Although Hertz's book was widely praised and admired, it was also met with a general sense of dissatisfaction. Almost all of Hertz's contemporaries criticized Principles for the lack of any plausible way to construct a mechanism from the "hidden masses" that are particularly characteristic of Hertz's framework. This issue seemed especially glaring given the expectation that Hertz's work might lead to a model of the underlying workings of the ether. In this paper I seek an explanation for why Hertz seemed so unperturbed by the difficulties of constructing such a mechanism. In arriving at this explanation, I explore how the development of Hertz's image-theory of representation framed the project of Principles. The image-theory brings with it an austere view of the "essential content" of mechanics, only requiring a kind of structural isomorphism between symbolic representations and target phenomena. I argue that bringing this into view makes clear why Hertz felt no need to work out the kinds of mechanisms that many of his readers looked for. Furthermore, I argue that a crucial role of Hertz's hypothesis of hidden masses has been widely overlooked. Far from acting as a proposal for the underlying structure of the ether, I show that Hertz's hypothesis ruled out knowledge of such underlying structure.

Work and back pain: a prospective study of psychological, social and mechanical predictors of back pain severity.

Science.gov (United States)

Christensen, J O; Knardahl, S

2012-07-01

Studies relating occupational psychological and social factors to back pain have traditionally investigated a small number of exposure factors. The current study explored longitudinally a comprehensive set of specific psychological/social and mechanical work factors as predictors of back pain severity (defined as the product of back pain intensity and duration). Employees from 28 organizations in Norway, representing a wide variety of occupations, were surveyed with a follow-up period of 2 years. Several designs were tested: (1) cross-sectional analyses at baseline and follow-up; (2) prospective analyses with baseline exposure; (3) prospective analyses with average exposure over time [(T1+T2)/2]; and (4) prospective analyses with measures of change in exposure from T1 to T2. A total of 2808 employees responded at both time points. Fourteen psychological/social and two mechanical exposures were measured. Odds ratios (ORs) were computed by ordinal logistic regressions. Several psychological/social factors predicted back pain severity. After adjustment for age, sex, skill level, back pain severity at T1 and other exposure factors estimated to be potential confounders, the most consistent predictors of back pain were the protective factors decision control [lowest OR 0.68; 99% confidence interval (CI): 0.49-0.95], empowering leadership (lowest OR 0.59; 99% CI: 0.38-0.91) and fair leadership (lowest OR 0.54; 99% CI: 0.34-0.87). Some of the most important predictors included in this study were factors that have previously received little attention in back pain research. This emphasizes the importance of extending the list of factors possibly contributing to back pain. © 2011 National Institute of Occupational Health, Norway European Journal of Pain © 2011 European Federation of International Association for the Study of Pain Chapters.

The mechanics of head-supported load carriage by Nepalese porters.

Science.gov (United States)

Bastien, G J; Willems, P A; Schepens, B; Heglund, N C

2016-11-15

In the Everest valley of Nepal, because of the rugged mountain terrain, roads are nothing more than dirt paths and all material must be conveyed on foot. The Nepalese porters routinely carry head-supported loads, which often exceed their body mass, over long distances up and down the steep mountain footpaths. In Africa, women transport their loads economically thanks to an energy-saving gait adaptation. We hypothesized that the Nepalese porters may have developed a corresponding mechanism. To investigate this proposition, we measured the mechanical work done during level walking in Nepalese porters while carrying different loads at several speeds. Our results show that the Nepalese porters do not use an equivalent mechanism as the African women to reduce work. In contrast, the Nepalese porters develop an equal amount of total mechanical work as Western control subjects while carrying loads of 0 to 120% of their body mass at all speeds measured (0.5-1.7 m s -1 ), making even more impressive their ability to carry loads without any apparent mechanically determined tricks. Nevertheless, our results show that the Nepalese porters have a higher efficiency, at least at slow speeds and high loads. © 2016. Published by The Company of Biologists Ltd.

Study on the immunological suppressive mechanisms of the cyclophosphamide-administration and total body irradiation

International Nuclear Information System (INIS)

Wakizaka, Yoshitaka; Uchino, Junichi; Yang, Zi-Bo.

1994-01-01

High dose-cyclophosphamide (CP) administration and total body irradiation (TBI) are often used for bone marrow transplantation in order to eradicate the residual tumor cells and to induce the immunological tolerance in the recipients. But CP is difficult to use as an immunosuppressant because this drug has indefinite effects on host's immune status depending on the dose, i.e. augment the humoral antibody production in small dosage and inhibit the rejective reaction in large dosage. Thus we study on the immunological mechanisms of this drug and the TBI used often with CP for bone marrow transplantation in leukemic patients. 150 mg/kg of CP was administered via tail vein, and 3 Gy (300 rads) of X-ray was irradiated. CP could suppress the host's cellular immunity within 5 days after administration but TBI could within 3 days. Reversely, CP augmented the cellular immunity since 5 days after treatment. CP damaged the IL-2 production irreversibely, but IL-3 production was inhibited by CP for only a few days and recovered rapidly. These characters were thought to be a big help for the implantation and development of the multipotent stem cells in the recipient's body after transplantation. (author)

Work-related agricultural fatalities in Australia, 1982-1984.

Science.gov (United States)

Erlich, S M; Driscoll, T R; Harrison, J E; Frommer, M S; Leigh, J

1993-06-01

Work-related agricultural fatalities were examined as part of a larger population-based study of all work-related fatalities in Australia in the period 1982-1984. A total of 257 farm-related fatalities were identified, of which 223 were deaths of persons in the employed civilian labor force (19.4 deaths per 100,000 persons per year) and 34 were deaths of children less than 15 years of age. The fatality incidence was higher among men, older age groups, and nonmanagers in general and in certain occupations in particular. Mobile mechanical equipment (particularly tractors) was the main fatal agent, roll-overs accounting for many of the fatalities. Better provision of information to agricultural workers, improvements in compliance to and enforcement of legislation, and changes in farming work practices are recommended to improve the safety of farms and farm work.

Analogous Mechanisms of Selection and Updating in Declarative and Procedural Working Memory: Experiments and a Computational Model

Science.gov (United States)

Oberauer, Klaus; Souza, Alessandra S.; Druey, Michel D.; Gade, Miriam

2013-01-01

The article investigates the mechanisms of selecting and updating representations in declarative and procedural working memory (WM). Declarative WM holds the objects of thought available, whereas procedural WM holds representations of what to do with these objects. Both systems consist of three embedded components: activated long-term memory, a…

Psychological, social, and mechanical work exposures and disability retirement: a prospective registry study

Directory of Open Access Journals (Sweden)

Jan S. Emberland

2017-01-01

Full Text Available Abstract Background Relations between several occupational psychological and social factors and disability retirement remain largely unexplored. Knowledge of which specific aspects of the work environment that affect risk of disability is a prerequisite for the success of organizational interventions aiming to prevent premature work force exit. The objective of the present study was to determine contributions to registered disability retirement by a broad range of psychological and social work exposures while taking into account effects of mechanical exposure. Methods Written consent was obtained from 13 012 employees (96 organizations representing a wide range of occupations, to link their survey responses to data from the Norwegian national registry of disability compensation. Median follow-up time was 5.8 years. To determine effects of self-reported work exposures on risk of disability retirement hazard ratios (HR and 99% confidence intervals (99% CI were calculated with Cox regression analysis. Effects of sex, age group, skill level, sickness absence in the last three years, and work exposures estimated to be confounders were accounted for. Post hoc stratification by sex was conducted to explore if identified predictors affected risk of disability retirement differently in men compared to women. Results Contributors to higher risk of disability retirement were “role conflict” (high level HR 1.55 99% CI 1.07 to 2.24 and “physical workload” (high level HR 1.93 99% CI 1.39 to 2.68. Contributors to lower risk of disability retirement were “positive challenge” (high level HR 0.56 99% CI 0.34 to 0.93, “fair leadership” (high level HR 0.56 99% CI 0.39 to 0.81, and “control over work intensity” (high level HR 0.62, 99% CI 0.47 to 0.82. Direction of effects was not dependent on sex in any of the five identified predictors. Conclusions Several specific psychological and social work factors are independent contributors to risk of

Nutritional evaluation of working Malay women in Kuala Lumpur as studied by total food duplicate method.

Science.gov (United States)

Shimbo, S; Moon, C S; Zhang, Z W; Watanabe, T; Ismail, N H; Ali, R M; Noor, I; Nakatsuka, H; Ikeda, M

1996-10-01

Nutrient intake was surveyed by the total food duplicate method in 49 adult ethnically Malay women (at the ages of 18 to 47 years and mostly at 30-39 years) working in Kuala Lumpur, Malaysia. Simultaneously, hematological examinations, serum biochemistry, anthropometry and clinical examination were conducted. Nutrient intakes were estimated in reference to the weight of each food item and the standard food composition tables. Lunch was the most substantial meal of the day with rice as a staple food. Compared with the Recommended Dietary Allowance (RDA) values, daily intakes of energy (1,917 kcal as an arithmetic mean), protein (62.2 g), vitamin B1 (0.83 mg) and vitamin B2 (1.18 mg) were sufficient, but intakes of minerals [i.e., calcium (347.8 mg) and iron (12.5 mg)] and some vitamins [i.e., vitamin A (equivalent to 627 micrograms retinol) and niacin (7.84 mg)] were less than RDA. When evaluated on an individual basis, the prevalence of those who took less than 80% RDA was highest for iron (92%), followed by niacin (80%), calcium (57%) and vitamin A (57%). The presence of 7 hypohemoglobinemia cases may be related to the insufficient iron intake. Overweight cases (14 women) were also detected, the prevalence of which increased at advanced ages. Lipid intake was rather high (28% of total food on energy basis), for which the major source was plants with limited contribution from fish/shellfish.

Effectiveness of team nursing compared with total patient care on staff wellbeing when organizing nursing work in acute care wards: a systematic review.

Science.gov (United States)

King, Allana; Long, Lesley; Lisy, Karolina

2015-11-01

The organization of the work of nurses, according to recognized models of care, can have a significant impact on the wellbeing and performance of nurses and nursing teams. This review focuses on two models of nursing care delivery, namely, team and total patient care, and their effect on nurses' wellbeing. To examine the effectiveness of team nursing compared to total patient care on staff wellbeing when organizing nursing work in acute care wards. Participants were nurses working on wards in acute care hospitals.The intervention was the use of a team nursing model when organizing nursing work. The comparator was the use of a total patient care model.This review considered quantitative study designs for inclusion in the review.The outcome of interest was staff wellbeing which was measured by staff outcomes in relation to job satisfaction, turnover, absenteeism, stress levels and burnout. The search strategy aimed to find both published and unpublished studies from 1995 to April 21, 2014. Quantitative papers selected for retrieval were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute. Data was extracted from papers included in the review using the standardized data extraction tool from the Joanna Briggs Institute. The data extracted included specific details about the interventions, populations, study methods and outcomes of significance to the review question and its specific objectives. Due to the heterogeneity of the included quantitative studies, meta-analysis was not possible. Results have been presented in a narrative form. The database search returned 10,067 records. Forty-three full text titles were assessed, and of these 40 were excluded, resulting in three studies being included in the review. Two of the studies were quasi experimental designs and the other was considered an uncontrolled before and after experimental study

Total and cause-specific mortality of U.S. nurses working rotating night shifts.

Science.gov (United States)

Gu, Fangyi; Han, Jiali; Laden, Francine; Pan, An; Caporaso, Neil E; Stampfer, Meir J; Kawachi, Ichiro; Rexrode, Kathryn M; Willett, Walter C; Hankinson, Susan E; Speizer, Frank E; Schernhammer, Eva S

2015-03-01

Rotating night shift work imposes circadian strain and is linked to the risk of several chronic diseases. To examine associations between rotating night shift work and all-cause; cardiovascular disease (CVD); and cancer mortality in a prospective cohort study of 74,862 registered U.S. nurses from the Nurses' Health Study. Lifetime rotating night shift work (defined as ≥3 nights/month) information was collected in 1988. During 22 years (1988-2010) of follow-up, 14,181 deaths were documented, including 3,062 CVD and 5,413 cancer deaths. Cox proportional hazards models estimated multivariable-adjusted hazard ratios (HRs) and 95% CIs. All-cause and CVD mortality were significantly increased among women with ≥5 years of rotating night shift work, compared to women who never worked night shifts. Specifically, for women with 6-14 and ≥15 years of rotating night shift work, the HRs were 1.11 (95% CI=1.06, 1.17) and 1.11 (95% CI=1.05, 1.18) for all-cause mortality and 1.19 (95% CI=1.07, 1.33) and 1.23 (95% CI=1.09, 1.38) for CVD mortality. There was no significant association between rotating night shift work and all-cancer mortality (HR≥15years=1.08, 95% CI=0.98, 1.19) or mortality of any individual cancer, with the exception of lung cancer (HR≥15years=1.25, 95% CI=1.04, 1.51). Women working rotating night shifts for ≥5 years have a modest increase in all-cause and CVD mortality; those working ≥15 years of rotating night shift work have a modest increase in lung cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity. Copyright © 2015 American Journal of Preventive Medicine. All rights reserved.

Mechanisms of biopower and neoliberal governmentality in precarious work: Mobilizing the dependent self-employed as independent business owners

NARCIS (Netherlands)

Moisander, J.; Groß, C.; Eräranta, K.

2018-01-01

In the contemporary conditions of neoliberal governmentality, and the emerging ‘gig economy,’ standard employment relationships appear to be giving way to precarious work. This article examines the mechanisms of biopower and techniques of managerial control that underpin—and produce consent

Mechanical ventilation and the total artificial heart: optimal ventilator trigger to avoid post-operative autocycling - a case series and literature review

Directory of Open Access Journals (Sweden)

Arabia Francisco A

2010-05-01

Full Text Available Abstract Many patients with end-stage cardiomyopathy are now being implanted with Total Artificial Hearts (TAHs. We have observed individual cases of post-operative mechanical ventilator autocycling with a flow trigger, and subsequent loss of autocycling after switching to a pressure trigger. These observations prompted us to do a retrospective review of all TAH devices placed at our institution between August 2007 and May 2009. We found that in the immediate post-operative period following TAH placement, autocycling was present in 50% (5/10 of cases. There was immediate cessation of autocycling in all patients after being changed from a flow trigger of 2 L/minute to a pressure trigger of 2 cm H2O. The autocycling group was found to have significantly higher CVP values than the non-autocycling group (P = 0.012. Our data suggest that mechanical ventilator autocycling may be resolved or prevented by the use of a pressure trigger rather than a flow trigger setting in patients with TAHs who require mechanical ventilation.

Type D personality in the general population: a systematic review of health status, mechanisms of disease, and work-related problems

Directory of Open Access Journals (Sweden)

Denollet Johan

2010-01-01

Full Text Available Abstract Background The objective was to review all available literature concerning Type D (distressed personality among the general population and to discuss its implications for research on health status, disease-promoting mechanisms and work-related problems in non-clinical populations. Methods A computerized search of the literature was performed independently and in duplicate by both investigators on December 21st, 2009. Published research reports were included if they studied Type D personality among the general population. Nineteen articles were selected and they were subjected to an 11-item standardised quality checklist by both investigators. Results The methodological quality of the selected studies was adequate to high. The studies included in this review showed that the presence of Type D characteristics had a negative impact on mental health status (more symptoms of depression, anxiety, post-traumatic stress disorder, mental distress, passive coping, and less social support and physical health status (more somatic complaints, lower health status, more influenza-like illness reporting. Other studies reported on behavioral and biological mechanisms of disease in apparently healthy individuals with a Type D personality. Finally, some studies also showed a negative effect of Type D personality on work-related problems (higher absence-leave, higher levels of vital exhaustion and burnout, and more work-related stress. Conclusions Type D personality is a vulnerability factor for general psychological distress that affects mental and physical health status and is associated with disease-promoting mechanisms and work-related problems in apparently healthy individuals.

Current Status of Experimental and Theoretical Work on Sodium/Fuel Interaction (SFI) at Karlsruhe 'Code Developments'

International Nuclear Information System (INIS)

Beutel, H.; Bojarsky, E.; Reiser, H.; Caldarola, L.; Jacobs, H.; Zyszkowski, W.

1976-01-01

The theoretical work follows two main lines: A. Code development; B. Theoretical work on fragmentation. Two computer codes have been developed. The first code contains a heat transfer model (during the vaporization phase) based on the inverse Leidenfrost phenomenon (which has been observed experimentally in water). The exact solution of the heat diffusion equation in a sphere is included in the code. The code accounts for the time history of each fuel particle by means of specially averaged temperature values. The presence of fission gases can also be taken into account. A size distribution of fuel particles has also been incorporated in the code as well as the effect of the friction due to the channel walls and that of the pressure losses at channel outlet. An extensive parametric study has been carried out with this code. The main conclusions are the following: 1. Total mechanical work strongly decreases with the fragmentation and/or mixing time constants. 2. Vapour blanketing during the vaporization phase is effective only if accompanied by a relatively slow process of fragmentation and mixing. In this case total mechanical work strongly decreased with degree of vapour blanketing. 3. Total mechanical work rises with initial length of sodium piston. 4. Time to empty the 120 cm long channel is 15-20 msecs. for values of the fragmentation and/or mixing time constants of the order of 5-10 msecs. 5. Effects due to particle size distribution and gas content are important only fora rapid fragmentation and mixing process. It must be painted out that (as far as the gas is concerned) this conclusion is valid only within the limits of the effects (due to the gas) which have been considered in the model. Propagation effects can be analysed by using the second code. The interaction region can be subdivided into an arbitrary number of sections, each containing fuel and coolant. The thermal conductivity of the liquid sodium has also been taken into account, as well as the

Total food duplicate study on nutrient intake of working women in Manila, the Philippines.

Science.gov (United States)

Nakatsuka, H; Zhang, Z W; Agetano, M G; Subida, R D; Inouguchi, N; Watanabe, T; Shimbo, S; Higashikawa, K; Ikeda, M

1998-03-01

Intakes of various nutrients by working women in Manila, the Philippines, was surveyed by the total food duplicate method, with foci to elucidate relative weight of three meals and snack in addition to quantitative evaluation of nutrient intakes. In practice, 45 women (average age; 37.2 years) volunteered, who were all nonsmokers and nonhabitual drinkers, and mostly married. In parallel, hematology, serum biochemistry, anthropometry and clinical examinations were conducted. On average, the women took 1787 kcal energy, 57 g protein, and 54 g lipid daily. Comparison with the Recommended Dietary Allowances (RDA) for Filipinos showed that intakes of energy and major nutrients were adequate, whereas that of minerals (e.g., 15 mg Fe/day vs. 26 mg Fe/day as RDA) and vitamins (e.g., 0.65 mg vitamin B1/day vs. 1 mg/day as RDA) were generally insufficient. Prevalence of anemia was however rather low with an average hemoglobin concentration of 12.9 g/100 ml blood. Rice was the staple source of energy for daily life, and beef rather than fish and shellfish was the leading source of protein. Lunch was the richest meal of a day (with the largest intake of energy, protein and lipid), and snacks rather than dinner appeared to be next substantial.

Applying Statistical Mechanics to pixel detectors

International Nuclear Information System (INIS)

Pindo, Massimiliano

2002-01-01

Pixel detectors, being made of a large number of active cells of the same kind, can be considered as significant sets to which Statistical Mechanics variables and methods can be applied. By properly redefining well known statistical parameters in order to let them match the ones that actually characterize pixel detectors, an analysis of the way they work can be performed in a totally new perspective. A deeper understanding of pixel detectors is attained, helping in the evaluation and comparison of their intrinsic characteristics and performance

Rehearsal of To-Be-Remembered Items Is Unnecessary to Perform Directed Forgetting within Working Memory: Support for an Active Control Mechanism

Science.gov (United States)

Festini, Sara B.; Reuter-Lorenz, Patricia A.

2017-01-01

Directed forgetting tasks instruct people to forget targeted memoranda. In the context of working memory, people attempt to forget representations that are currently held in mind. Here, we evaluated candidate mechanisms of directed forgetting within working memory, by (a) testing the influence of articulatory suppression, a rehearsal-reducing and…

Nontraumatic Fracture of the Femoral Condylar Prosthesis in a Total Knee Arthroplasty Leading to Mechanical Failure

Directory of Open Access Journals (Sweden)

Girish N. Swamy

2014-01-01

Full Text Available This paper reports a case of fatigue fracture of the femoral component in a cruciate-retaining cemented total knee arthroplasty (TKA. A 64-year-old man had undergone a primary TKA for osteoarthritis 10 years previously at another institution using the PFC-Sigma prosthesis. The patient recovered fully and was back to his regular activities. He presented with a history of sudden onset pain and locking of the left knee since the preceding three months. There was no history of trauma, and the patient was mobilizing with difficulty using crutches. Radiographs revealed fracture of the posterior condyle of the femoral prosthesis. Revision surgery was performed as an elective procedure revealing the broken prosthesis. The TC3RP-PFC revision prosthesis was used with a medial parapatellar approach. The patient recovered fully without any squeal. Mechanical failure of the knee arthroplasty prosthesis is rare, and nontraumatic fracture of the femoral metallic component has not been reported before.

Nontraumatic fracture of the femoral condylar prosthesis in a total knee arthroplasty leading to mechanical failure.

Science.gov (United States)

Swamy, Girish N; Quah, Conal; Bagouri, Elmunzar; Badhe, Nitin P

2014-01-01

This paper reports a case of fatigue fracture of the femoral component in a cruciate-retaining cemented total knee arthroplasty (TKA). A 64-year-old man had undergone a primary TKA for osteoarthritis 10 years previously at another institution using the PFC-Sigma prosthesis. The patient recovered fully and was back to his regular activities. He presented with a history of sudden onset pain and locking of the left knee since the preceding three months. There was no history of trauma, and the patient was mobilizing with difficulty using crutches. Radiographs revealed fracture of the posterior condyle of the femoral prosthesis. Revision surgery was performed as an elective procedure revealing the broken prosthesis. The TC3RP-PFC revision prosthesis was used with a medial parapatellar approach. The patient recovered fully without any squeal. Mechanical failure of the knee arthroplasty prosthesis is rare, and nontraumatic fracture of the femoral metallic component has not been reported before.

Characterizing new compositions of [001]C relaxor ferroelectric single crystals using a work-energy model

Science.gov (United States)

Gallagher, John A.

2016-04-01

The desired operating range of ferroelectric materials with compositions near the morphotropic phase boundary is limited by field induced phase transformations. In [001]C cut and poled relaxor ferroelectric single crystals the mechanically driven ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation is hindered by antagonistic electrical loading. Instability around the phase transformation makes the current experimental technique for characterization of the large field behavior very time consuming. Characterization requires specialized equipment and involves an extensive set of measurements under combined electrical, mechanical, and thermal loads. In this work a mechanism-based model is combined with a more limited set of experiments to obtain the same results. The model utilizes a work-energy criterion that calculates the mechanical work required to induce the transformation and the required electrical work that is removed to reverse the transformation. This is done by defining energy barriers to the transformation. The results of the combined experiment and modeling approach are compared to the fully experimental approach and error is discussed. The model shows excellent predictive capability and is used to substantially reduce the total number of experiments required for characterization. This decreases the time and resources required for characterization of new compositions.

Testing principle working mechanisms of the health action process approach for subjective physical age groups.

Science.gov (United States)

Wienert, Julian; Kuhlmann, Tim; Fink, Sebastian; Hambrecht, Rainer; Lippke, Sonia

2016-01-01

This study investigated differences in social-cognitive predictors and self-regulatory planning, as proposed by the health action process approach (HAPA), across three different subjective physical age groups for physical activity. With a cross-sectional design, 521 participants across the chronological age span from 25 to 86 years (M = 48.79; SD = 12.66) were separated into three groups: those who feel physically younger than they are in terms of chronological age, the same perceived and chronological age, and feeling physically older compared to their chronological age. Participants were assessed regarding their perceived vulnerability, outcome expectancies, general intentions, planning, self-efficacy, and stages of physical activity (non-intenders, intenders, and actors). Data were analysed via mean comparison and multigroup structural equation modelling. Mean differences for all but one construct were eminent in all groups, generally showing that those feeling physically younger also report better social-cognitive predictors of physical activity (e.g. lower perceived vulnerability) in comparison to those who feel the same age or older. The model showed that basic working mechanisms of the HAPA can be applied to all groups. With that, the results provide for the first time evidence that principle working mechanism of the HAPA can be applied to all subjective physical age groups. These may be used to tailor health promoting interventions according to participants' needs as a more suitable proxy than chronological age.

How beauty works. Theoretical mechanisms and two empirical applications on students' evaluation of teaching.

Science.gov (United States)

Wolbring, Tobias; Riordan, Patrick

2016-05-01

Plenty of studies show that the physical appearance of a person affects a variety of outcomes in everyday life. However, due to an incomplete theoretical explication and empirical problems in disentangling different beauty effects, it is unclear which mechanisms are at work. To clarify how beauty works we present explanations from evolutionary theory and expectation states theory and show where both perspectives differ and where interlinkage appears promising. Using students' evaluations of teaching we find observational and experimental evidence for the different causal pathways of physical attractiveness. First, independent raters strongly agree over the physical attractiveness of a person. Second, attractive instructors receive better student ratings. Third, students attend classes of attractive instructors more frequently - even after controlling for teaching quality. Fourth, we find no evidence that attractiveness effects become stronger if rater and ratee are of the opposite sex. Finally, the beauty premium turns into a penalty if an attractive instructor falls short of students' expectations. Copyright © 2016 Elsevier Inc. All rights reserved.

Work-related basic need satisfaction as a predictor of work ...

African Journals Online (AJOL)

This study examines the relationship between work-related basic need satisfaction and work engagement. Data were obtained from a total of 203 academics who are employed in various universities of Turkey. In this research Work-Related Basic Need Satisfaction Scale and The Turkish Form of Utrecht Work Engagement ...

Flow of Liquid in Flat Gaps of the Satellite Motor Working Mechanism

Directory of Open Access Journals (Sweden)

Sliwiński Paweł

2014-04-01

Full Text Available The article describes the methodology and results of investigations of the flow of oil and HFA-E emulsion in flat gaps of the working mechanism of a satellite motor. The flow of liquid in those gaps is turbulent and not fully developed. The article presents two methods of modelling this flow. Method I makes use of the Darcy-Weisbach formula, while Method II bases on the assumption that in the variable-length gaps the flow is turbulent in the area where the length is the smallest and laminar where the length is the largest. Consequently, the flow in such gaps can be modelled as the sum of laminar and turbulent flows. The results obtained in the experiment have made the basis for calculating relevant coefficients and assessing the proportion of turbulence in the flow modelled using both methods

Totality eclipses of the Sun

CERN Document Server

Littmann, Mark; Willcox, Ken

2008-01-01

A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

Total Synthesis of Ionic Liquid Systems for Dissolution of Lunar Simulant

Science.gov (United States)

Sharpe, Robert J.; Karr, Laurel J.; Paley, Mark S.

2010-01-01

For purposes of Space Resource Utilization, work in the total synthesis of a new ionic liquid system for the extraction of oxygen and metals from lunar soil is studied and described. Reactions were carried out according to procedures found in the chemical literature, analyzed via Thin-Layer Chromatography and 1H Nuclear Magnetic Resonance Spectroscopy and purified via vacuum distillation and rotary evaporation. Upon final analysis via 1H NMR, it was found that while the intermediates of the synthesis had been achieved, unexpected side products were also present. The mechanisms and constraints of the synthesis are described as well as the final results of the project and recommendations for continued study

Working group inciting mechanisms; Groupe de travail mecanismes incitatifs

Energy Technology Data Exchange (ETDEWEB)

Bureau, D

2001-07-01

This document deals with the inciting mechanisms under consideration in the framework of the greenhouse effect fight. The advantages and disadvantages, the coherence of these mechanisms and their articulation with the taxation, have been specified. A whole evaluation of the various scenario, taking into account the implementing problems and the evolution in an international context, is proposed. (A.L.B.)

[Inhibitory effect and underlying mechanism of total saponins from Paris polyphylla var. yunnanensis on the proliferation of salivary adenoid cystic carcinoma ACC-83 cells].

Science.gov (United States)

Qiumin, He; Biao, Xu; Weihong, Wang; Chongyun, Bao; Shaowei, Hu

2017-06-01

To investigate the inhibitory effect and underlying mechanism of total saponins from Paris polyphylla var. yunnanensis on the proliferation of salivary adenoid cystic carcinoma ACC-83 cells. In vitro cell culture was performed. The proliferation of ACC-83 cells treated with different concentrations (5, 10, 20, 40, 60, 80, 100 μg·mL⁻¹) of total saponins from Paris polyphylla var. yunnanensis was observed using CCK-8 assay. Meanwhile, the apoptosis of ACC-83 cells treated with different concentrations (25, 50, 100 μg·mL⁻¹) of the total saponins was observed using flow cytometry. The expression levels of macrophage migration inhibitory factor (MIF) and CD74 were measured using Western blot and reverse transcription-polymerase chain reaction. The total saponins from Paris polyphylla var. yunnanensis induced apoptosis and expressed dose-effect relationship. ACC-83 cells expressed MIF and CD74, and the total saponins suppressed MIF and CD74 expression in ACC-83 cells. The total saponins from Paris polyphylla var. yunnanensis can significantly inhibit the proliferation, suppress MIF and CD74 expression, and promote apoptosis in ACC-83 cells. This study provides a theoretical basis for the treatment of salivary adenoid cystic carcinoma using Paris polyphylla var. yunnanensis.
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Total Variation Depth for Functional Data

KAUST Repository

Huang, Huang

2016-11-15

There has been extensive work on data depth-based methods for robust multivariate data analysis. Recent developments have moved to infinite-dimensional objects such as functional data. In this work, we propose a new notion of depth, the total variation depth, for functional data. As a measure of depth, its properties are studied theoretically, and the associated outlier detection performance is investigated through simulations. Compared to magnitude outliers, shape outliers are often masked among the rest of samples and harder to identify. We show that the proposed total variation depth has many desirable features and is well suited for outlier detection. In particular, we propose to decompose the total variation depth into two components that are associated with shape and magnitude outlyingness, respectively. This decomposition allows us to develop an effective procedure for outlier detection and useful visualization tools, while naturally accounting for the correlation in functional data. Finally, the proposed methodology is demonstrated using real datasets of curves, images, and video frames.

Conditional bistability, a generic cellular mnemonic mechanism for robust and flexible working memory computations.

Science.gov (United States)

Rodriguez, Guillaume; Sarazin, Matthieu; Clemente, Alexandra; Holden, Stephanie; Paz, Jeanne T; Delord, Bruno

2018-04-30

Persistent neural activity, the substrate of working memory, is thought to emerge from synaptic reverberation within recurrent networks. However, reverberation models do not robustly explain fundamental dynamics of persistent activity, including high-spiking irregularity, large intertrial variability, and state transitions. While cellular bistability may contribute to persistent activity, its rigidity appears incompatible with persistent activity labile characteristics. Here, we unravel in a cellular model a form of spike-mediated conditional bistability that is robust, generic and provides a rich repertoire of mnemonic computations. Under asynchronous synaptic inputs of the awakened state, conditional bistability generates spiking/bursting episodes, accounting for the irregularity, variability and state transitions characterizing persistent activity. This mechanism has likely been overlooked because of the sub-threshold input it requires and we predict how to assess it experimentally. Our results suggest a reexamination of the role of intrinsic properties in the collective network dynamics responsible for flexible working memory. SIGNIFICANCE STATEMENT This study unravels a novel form of intrinsic neuronal property, i.e. conditional bistability. We show that, thanks of its conditional character, conditional bistability favors the emergence of flexible and robust forms of persistent activity in PFC neural networks, in opposition to previously studied classical forms of absolute bistability. Specifically, we demonstrate for the first time that conditional bistability 1) is a generic biophysical spike-dependent mechanism of layer V pyramidal neurons in the PFC and that 2) it accounts for essential neurodynamical features for the organisation and flexibility of PFC persistent activity (the large irregularity and intertrial variability of the discharge and its organization under discrete stable states), which remain unexplained in a robust fashion by current models

Anti-arthritic effect of total anthraquinone from Polygonum ...

African Journals Online (AJOL)

Purpose: To study the anti-arthritic effect of total anthraquinone from Polygonum cuspidatum (TAPC) on type II collagen-induced arthritis (CIA) in rats, and to investigate the underlying mechanism(s). Methods: CIA rats were prepared and treated orally with TAPC at doses of 50, 100 and 200 mg/kg/day, for 24 days.

Water transport mechanisms across inorganic membranes in rad waste treatment by electro dialysis

International Nuclear Information System (INIS)

Andalaft, E.; Labayru, R.

1992-01-01

The work described in this paper deals with effects and mechanisms of water transport across an inorganic membrane, as related to some studied on the concentration of caesium, strontium, plutonium and other cations of interest to radioactive waste treatment. Several different water transport mechanisms are analysed and assessed as to their individual contribution towards the total transference of water during electro-dialysis using inorganic membranes. Water transfer assisted by proton jump mechanism, water of hydration transferred along with the ions, water related to thermo-osmotic effect, water transferred by concentration gradient and water transferred electrolytically under zeta potential surface charge drive are some of the different mechanism discussed. (author)

Z3 -vertex magic total labeling and Z3 -edge magic total labelingfor the extended duplicate graph of quadrilateral snake

Science.gov (United States)

Indira, P.; Selvam, B.; Thirusangu, K.

2018-04-01

Based on the works of Kotzig, Rosa and MacDougall et.al., we present algorithms and prove the existence of Z3-vertex magic total labeling and Z3-edge magic total labeling for the extended duplicate graph of quadrilateral snake.

Bone-femoral component interface gap after sagittal mechanical axis alignment is filled with new bone after cementless total knee arthroplasty.

Science.gov (United States)

Kuriyama, Shinichi; Hyakuna, Katsufumi; Inoue, Satoshi; Kawai, Yasutsugu; Tamaki, Yasuyuki; Ito, Hiromu; Matsuda, Shuichi

2018-05-01

This study retrospectively evaluated the fate of mismatch between an uncemented femoral component and each femoral cut surface (i.e., wedge-shaped gap) relative to sagittal mechanical alignment in total knee arthroplasty (TKA). Primary TKA was performed on 99 consecutive knees. The femoral components were aligned to the sagittal mechanical axis with CT-based navigation. All patients were assessed with postoperative true lateral radiographs. Bone-side surfaces of the uncemented femoral component were divided into five zones: anterior flange, anterior chamfer, posterior chamfer, posterior part, and distal part, which were defined as zones 1 to 5, respectively. Bone filling of wedge-shaped gaps in each zone was evaluated after 1 year. Femoral anterior notching did not occur. However, wedge-shaped gaps were observed in at least one zone in 23 of 99 knees (23%), most frequently in zone 5 (18%). There were 9 and 7 gaps in zones 1 and 2, respectively. The femoral component showed malpositioning of approximately 3° of flexion in cases with wedge-shaped gaps in zones 2 and/or 5. After one year, 67% (6/9) of zone 1, 100% (7/7) of zone 2, and 94% (17/18) of zone 5 wedge-shaped gaps were filled in with new bone. Femoral alignment relative to sagittal mechanical axis caused wedge-shaped gaps due to unstable anterior bone cutting through hard bone, but the small gaps were not clinically significant and filled in within one year. Sagittal setting of the femoral component should aim for the anatomical axis rather than the mechanical axis. IV.

Lower limb joint work and joint work contribution during downhill and uphill walking at different inclinations.

Science.gov (United States)

Alexander, Nathalie; Strutzenberger, Gerda; Ameshofer, Lisa Maria; Schwameder, Hermann

2017-08-16

Work performance and individual joint contribution to total work are important information for creating training protocols, but were not assessed so far for sloped walking. Therefore, the purpose of this study was to analyze lower limb joint work and joint contribution of the hip, knee and ankle to total lower limb work during sloped walking in a healthy population. Eighteen male participants (27.0±4.7yrs, 1.80±0.05m, 74.5±8.2kg) walked on an instrumented ramp at inclination angles of 0°, ±6°, ±12° and ±18° at 1.1m/s. Kinematic and kinetic data were captured using a motion-capture system (Vicon) and two force plates (AMTI). Joint power curves, joint work (positive, negative, absolute) and each joint's contribution to total lower limb work were analyzed throughout the stance phase using an ANOVA with repeated measures. With increasing inclination positive joint work increased for the ankle and hip joint and in total during uphill walking. Negative joint work increased for each joint and in total work during downhill walking. Absolute work was increased during both uphill (all joints) and downhill (ankle & knee) walking. Knee joint contribution to total negative and absolute work increased during downhill walking while hip and ankle contributions decreased. This study identified, that, when switching from level to a 6° and from 6° to a 12° inclination the gain of individual joint work is more pronounced compared to switching from 12° to an 18° inclination. The results might be used for training recommendations and specific training intervention with respect to sloped walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Total Lightning as an Indicator of Mesocyclone Behavior

Science.gov (United States)

Stough, Sarah M.; Carey, Lawrence D.; Schultz, Christopher J.

2014-01-01

Apparent relationship between total lightning (in-cloud and cloud to ground) and severe weather suggests its operational utility. Goal of fusion of total lightning with proven tools (i.e., radar lightning algorithms. Preliminary work here investigates circulation from Weather Suveilance Radar- 1988 Doppler (WSR-88D) coupled with total lightning data from Lightning Mapping Arrays.

Work-Life Balance and Work Satisfaction in Workplace

OpenAIRE

Soo, Chin Hock

2014-01-01

This study aims to investigate whether the workplace environment in an ICT organizations are conducive for the employees to use work-life balance and secondary investigation will involving whether the ability to have work-life balance will increase the happiness and this job satisfaction and leads to higher productivity. A questionnaire which consisted of all the work-life balance activities in the ICT organization were sent out and a total of 94 respondents whom worked in ICT organizations h...

Equal Pay for Equal Work: Medicare Procedure Volume and Reimbursement for Male and Female Surgeons Performing Total Knee and Total Hip Arthroplasty.

Science.gov (United States)

Holliday, Emma B; Brady, Christina; Pipkin, William C; Somerson, Jeremy S

2018-02-21

The observed sex gap in physician salary has been the topic of much recent debate in the United States, but it has not been well-described among orthopaedic surgeons. The objective of this study was to evaluate for sex differences in Medicare claim volume and reimbursement among orthopaedic surgeons. The Medicare Provider Utilization and Payment Public Use File was used to compare claim volume and reimbursement between female and male orthopaedic surgeons in 2013. Data were extracted for each billing code per orthopaedic surgeon in the year 2013 for total claims, surgical claims, total knee arthroplasty (TKA) claims, and total hip arthroplasty (THA) claims. A total of 20,546 orthopaedic surgeons who treated traditional Medicare patients were included in the initial analysis. Claim volume and reimbursement received were approximately twofold higher for all claims and more than threefold higher for surgical claims for male surgeons when compared with female surgeons (p 10 TKAs and THAs, respectively, in 2013 for Medicare patients and were included in the subset analyses. Although male surgeons performed a higher mean number of TKAs than female surgeons (mean and standard deviation, 37 ± 33 compared with 26 ± 17, respectively, p men and women for TKA or THA ($1,135 ± $228 compared with $1,137 ± $184 for TKA, respectively, p = 0.380; $1,049 ± $226 compared with $1,043 ± $266 for THA, respectively, p = 0.310). Female surgeons had a lower number of total claims and reimbursements compared with male surgeons. However, among surgeons who performed >10 THAs and TKAs, there were no sex differences in the mean reimbursement payment per surgeon. The number of women in orthopaedics is rising, and there is much interest in how their productivity and compensation compare with their male counterparts.

Live to work or love to work: work craving and work engagement.

Science.gov (United States)

Wojdylo, Kamila; Baumann, Nicola; Fischbach, Lis; Engeser, Stefan

2014-01-01

According to the theory of work craving, a workaholic has a craving for self-worth compensatory incentives and an expectation of relief from negative affect experienced through neurotic perfectionism and an obsessive-compulsive style of working. Research has shown that workaholism and work engagement should be considered as two distinct work styles with different health consequences. However, the mechanisms underlying the adoption of these work styles have been neglected. The present study proposes that work craving and work engagement are differentially associated with self-regulatory competencies and health. In particular, we expected that the working styles mediate the relationships between emotional self-regulation and health. In the cross-sectional study, 469 teachers from German schools completed online administered questionnaires. By means of structural equation modeling, we tested two indirect paths: a) from self-relaxation deficits via work craving to poor health and b) from self-motivation competencies via work engagement to good health. As expected, we found evidence that a) the negative relationship of self-relaxation deficits on health was partially mediated by work craving and b) the positive relationship of self-motivation competencies on health was partially mediated by work engagement. The present study emphasizes the importance of self-regulation competencies for healthy or unhealthy work styles. Whereas work craving was associated with a low ability to down-regulate negative emotions and poor health, work engagement was associated with a high ability to up-regulate positive emotions and good health.

Employee benefits in a total rewards framework.

Science.gov (United States)

Kwon, Jane; Hein, Pam

2013-01-01

Benefits represent one of the largest investments a company makes in its talent. However, our tendency can be to design, deliver and communicate benefits programs independently, without fully considering how those programs fit within a bigger picture of total rewards. Sure, we need to manage and execute individual benefit programs--but not at the expense of getting a real return on our more significant investment in talent. This article provides employers with perspectives on the value of managing benefits within the broader framework of total rewards, why it works and, most importantly, how to make it work.

An approach to total quality assurance

International Nuclear Information System (INIS)

Archer, L.G.

1976-01-01

Total Quality Assurance must be based on amalgamating three quality functions: effective quality control, competent inspection, and regularly audited Quality Assurance programmes. In applying these functions the fuel supplier must regard each of his sub-contractors as part of his own works and ensure a common policy of motivated Quality Assurance throughout his own works and those of his suppliers. (author)

Astragalus polysaccharides lowers plasma cholesterol through mechanisms distinct from statins.

Directory of Open Access Journals (Sweden)

Yunjiu Cheng

Full Text Available To determine the efficacy and underlying mechanism of Astragalus polysaccharides (APS on plasma lipids in hypercholesterolemia hamsters. The effect of APS (0.25 g/kg/d on plasma and liver lipids, fecal bile acids and neutral sterol, cholesterol absorption and synthesis, HMG-CoA reductase activity, and gene and protein expressions in the liver and small intestine was investigated in twenty-four hypercholesterolemia hamsters. Treatment periods lasted for three months. APS significantly lowered plasma total cholesterol by 45.8%, triglycerides by 30%, and low-density lipoprotein-cholesterol by 47.4%, comparable to simvastatin. Further examinations revealed that APS reduced total cholesterol and triglycerides in the liver, increased fecal bile acid and neutral sterol excretion, inhibited cholesterol absorption, and by contrast, increased hepatic cholesterol synthesis and HMG-CoA reductase activity. Plasma total cholesterol or low-density lipoprotein-cholesterol levels were significantly correlated with cholesterol absorption rates. APS up-regulated cholesterol-7α-hydroxylase and LDL-receptor gene expressions. These new findings identify APS as a potential natural cholesterol lowering agent, working through mechanisms distinct from statins.

Mixed total screening for sulfur isotope

International Nuclear Information System (INIS)

Cui Bin; Zhao Lei; Zhan Zhaoyang; He Zhijun

2003-01-01

The research on modern economic geology indicates that most ore deposits formed with characters of multi-origin, multi-stage and multi-genesis. Quantificational research of Sulfur isotope origin is a difficult problem that puzzles Geochemists all along. So the formation process of an ore deposit can be taken as the mix or the superposition of multi totals, which can be described by the mathematics model of mixed total screening. In the study of mid-down Yangtze River and Dongpo ore field in Hunan province, the authors successfully applied the mathematics model of mixed total screening, quantificationally resolved the problem of Sulfur isotope origin and mineralizing matter origin, and found out the mineralizing mechanism. This is very valuable. (authors)

Understanding work related musculoskeletal pain: does repetitive work cause stress symptoms?

Science.gov (United States)

Bonde, J P; Mikkelsen, S; Andersen, J H; Fallentin, N; Baelum, J; Svendsen, S W; Thomsen, J F; Frost, P; Kaergaard, A

2005-01-01

Pain in the neck and upper extremity is reported with high frequency in repetitive work. Mechanical overload of soft tissues seems a plausible mechanism, but psychological factors have received considerable attention during the past decade. If psychological factors are important for development of regional pain in repetitive work, stress symptoms would likely be on the causal path. To examine whether objective measures of repetitive monotonous work are related to occurrence and development of stress symptoms. In 1994-95, 2033 unskilled workers with continuous repetitive work and 813 workers with varied work were enrolled. Measures of repetitiveness and force requirements were quantified using video observations to obtain individual exposure estimates. Stress symptoms were recorded at baseline and after approximately one, two, and three years by the Setterlind Stress Profile Inventory. Repetitive work, task cycle time, and quantified measures of repetitive upper extremity movements including force requirements were not related to occurrence of stress symptoms at baseline or development of stress symptoms during three years of follow up. The findings do not indicate that repetitive work is associated with stress symptoms, but small effects cannot be ruled out. Thus the results question the importance of mental stress mechanisms in the causation of regional pain related to repetitive work. However, the findings should be interpreted with caution because the stress inventory has not been validated against a gold standard.

Evaluation of the mechanical properties of Niobium modified cast AISI H 13 hot work tool steel

International Nuclear Information System (INIS)

Noorian, A.; Kheirandish, Sh.; Saghafian, H.

2010-01-01

In this research, the effects of partially replacing of vanadium and molybdenum with niobium on the mechanical properties of AISIH 13 hot-work tool steel have been studied. Cast samples made of the modified new steel were homogenized and austenitized at different conditions, followed by tempering at the specified temperature ranges. Hardness, red hardness, three point bending test and Charpy impact test were carried out to evaluate the mechanical properties together with characterizing the microstructure of the modified steel using scanning electron microscope. The results show that niobium addition modifies the cast structure of Nb-alloyed steel, and increases its maximum hardness. It was found that bending strength; bending strain, impact strength, and red hardness of the modified cast steel are also higher than those of the cast H13 steel, and lower than those of the wrought H13 steel.

How Electroconvulsive Therapy Works?: Understanding the Neurobiological Mechanisms

Science.gov (United States)

Singh, Amit; Kar, Sujita Kumar

2017-01-01

Electroconvulsive therapy (ECT) is a time tested treatment modality for the management of various psychiatric disorders. There have been a lot of modifications in the techniques of delivering ECT over decades. Despite lots of criticisms encountered, ECT has still been used commonly in clinical practice due to its safety and efficacy. Research evidences found multiple neuro-biological mechanisms for the therapeutic effect of ECT. ECT brings about various neuro-physiological as well as neuro-chemical changes in the macro- and micro-environment of the brain. Diverse changes involving expression of genes, functional connectivity, neurochemicals, permeability of blood-brain-barrier, alteration in immune system has been suggested to be responsible for the therapeutic effects of ECT. This article reviews different neurobiological mechanisms responsible for the therapeutic efficacy of ECT. PMID:28783929

Effect of Natural Aging and Cold Working on Microstructures and Mechanical Properties of Al-4.6Cu-0.5Mg-0.5Ag alloy

Science.gov (United States)

Chen, Yu-Te; Lee, Sheng-Long; Bor, Hui-Yun; Lin, Jing-Chie

2013-06-01

This research investigates the effects of natural aging and cold working prior to artificial aging on microstructures and mechanical properties of Al-4.6Cu-0.5Mg-0.5Ag alloy. Mechanical properties relative to microstructure variations were elucidated by the observations of the optical microscope (OM), differential scanning calorimeter (DSC), electrical conductivity meter (pct IACS), and transmission electron microscopy (TEM). The results showed that natural aging treatment has little noticeable benefit on the quantity of precipitation strengthening phases and mechanical properties, but it increases the precipitation strengthening rate at the initial stage of artificial aging. Cold working brings more lattice defects which suppress Al-Cu (GP zone) and Mg-Ag clustering, and therefore the precipitation of Ω phase decreases. Furthermore, more dislocations are formed, leading to precipitate the more heterogeneous nucleation of θ' phase. The above-mentioned precipitation phenomena and strain hardening effect are more obvious with higher degrees of cold working.

Operational resource theory of total quantum coherence

Science.gov (United States)

Yang, Si-ren; Yu, Chang-shui

2018-01-01

Quantum coherence is an essential feature of quantum mechanics and is an important physical resource in quantum information. Recently, the resource theory of quantum coherence has been established parallel with that of entanglement. In the resource theory, a resource can be well defined if given three ingredients: the free states, the resource, the (restricted) free operations. In this paper, we study the resource theory of coherence in a different light, that is, we consider the total coherence defined by the basis-free coherence maximized among all potential basis. We define the distillable total coherence and the total coherence cost and in both the asymptotic regime and the single-copy regime show the reversible transformation between a state with certain total coherence and the state with the unit reference total coherence. Extensively, we demonstrate that the total coherence can also be completely converted to the total correlation with the equal amount by the free operations. We also provide the alternative understanding of the total coherence, respectively, based on the entanglement and the total correlation in a different way.

Total hip reconstruction in acetabular dysplasia.

NARCIS (Netherlands)

Schller, H.M.; Dalstra, M.; Huiskes, R.; Marti, R.K.

1993-01-01

In acetabular dysplasia, fixation of the acetabular component of a cemented total hip prosthesis may be insecure and superolateral bone grafts are often used to augment the acetabular roof. We used finite element analysis to study the mechanical importance of the lateral acetabular roof and found

Live to work or love to work: work craving and work engagement.

Directory of Open Access Journals (Sweden)

Kamila Wojdylo

Full Text Available OBJECTIVE: According to the theory of work craving, a workaholic has a craving for self-worth compensatory incentives and an expectation of relief from negative affect experienced through neurotic perfectionism and an obsessive-compulsive style of working. Research has shown that workaholism and work engagement should be considered as two distinct work styles with different health consequences. However, the mechanisms underlying the adoption of these work styles have been neglected. The present study proposes that work craving and work engagement are differentially associated with self-regulatory competencies and health. In particular, we expected that the working styles mediate the relationships between emotional self-regulation and health. METHODS: In the cross-sectional study, 469 teachers from German schools completed online administered questionnaires. By means of structural equation modeling, we tested two indirect paths: a from self-relaxation deficits via work craving to poor health and b from self-motivation competencies via work engagement to good health. RESULTS: As expected, we found evidence that a the negative relationship of self-relaxation deficits on health was partially mediated by work craving and b the positive relationship of self-motivation competencies on health was partially mediated by work engagement. CONCLUSIONS: The present study emphasizes the importance of self-regulation competencies for healthy or unhealthy work styles. Whereas work craving was associated with a low ability to down-regulate negative emotions and poor health, work engagement was associated with a high ability to up-regulate positive emotions and good health.

Experimental mechanics in research work and in practice

International Nuclear Information System (INIS)

1989-01-01

The current state of the art in experimental mechanics is reflected and explained by the 34 conference papers of the 12th GESA symposium. Separate records of 12 papers have been prepared for the ENERGY database. (MM) [de

Mechanisms of overcoming ethical dilemmas in nowadays social work

OpenAIRE

MELKONYAN NELLI

2016-01-01

In social work, ethical principles have been important in several key respects, with regard to the nature of its mission; the relationships that social workers have with clients, colleagues, and members of the broader society; the methods of intervention that social workers use in their work. So, social work is situated between moral choice and professional ethical behavior, which allows orientating among the variety of moral requirements, evaluating activities taking into consideration moral...

The total artificial heart.

Science.gov (United States)

Cook, Jason A; Shah, Keyur B; Quader, Mohammed A; Cooke, Richard H; Kasirajan, Vigneshwar; Rao, Kris K; Smallfield, Melissa C; Tchoukina, Inna; Tang, Daniel G

2015-12-01

The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review.

Employees in Total Quality Management

Directory of Open Access Journals (Sweden)

M. G. Matlhape

2002-12-01

• affirmative action and divers ity management • skills shortages, training and development • low levels of employee well-being. Working with people requires fundamental understanding of the uniqueness of each individual with their own identity and set of preferences. It also requires an understanding of teams and the mechanisms of making a group of individuals work well or poorly together. This will assist managers to realise active participation, quality output from their workers through individualised, and team based motivational processes.

Renoprotective effect of total glucosides of paeony (TGP) and its mechanism in experimental diabetes.

Science.gov (United States)

Wu, Yonggui; Ren, Kejun; Liang, Chao; Yuan, Liang; Qi, Xiangming; Dong, Jing; Shen, Jijia; Lin, Shanyan

2009-01-01

Total glucosides of paeony (TGP), extracted from the root of Paeonia lactiflora pall, has been shown to have ant-inflammatory and antioxidative actions. The aims of this study were to elucidate the renoprotective effect of TGP and its mechanism in experimental diabetes. Streptozotocin-induced diabetic rats were treated with TGP for 8 weeks. Treatment with TGP at 50, 100, and 200 mg/kg significantly lowered 24-h urinary albumin excretion rate in diabetic rats. TGP treatment in all doses markedly attenuated glomerular volume, and treatment with TGP at 100 and 200 mg/kg markedly reduced indices for tubulointerstitial injury in diabetic rats. Western blot analysis showed that the expressions of 1 alpha (IV) collagen, intercellular adhesion molecule (ICAM)-1, interleukin (IL)-1, tumor necrosis factor (TNF)-alpha, NF-kappaB p65, and 3-nitrotyrosine (3-NT) protein were increased in the kidneys of diabetic rats; the increases in these proteins were all dose-dependently and significantly inhibited by TGP treatment. The expression of nephrin protein was significantly reduced in the kidneys from diabetic rats and markedly increased by TGP treatment. The expression of transforming growth factor (TGF)-beta1 protein in the kidney was also significantly increased in diabetic rats, which was significantly inhibited by treatment with TGP at all doses. Our data suggest that TGP treatment ameliorates early renal injury via the inhibition of expression of ICAM-1, IL-1, TNF-alpha, and 3-NT in the kidneys of diabetic rats.

Percutaneous dilatational tracheostomy following total artificial heart implantation.

Science.gov (United States)

Spiliopoulos, Sotirios; Dimitriou, Alexandros Merkourios; Serrano, Maria Rosario; Guersoy, Dilek; Autschbach, Ruediger; Goetzenich, Andreas; Koerfer, Reiner; Tenderich, Gero

2015-07-01

Coagulation disorders and an immune-altered state are common among total artificial heart patients. In this context, we sought to evaluate the safety of percutaneous dilatational tracheostomy in cases of prolonged need for mechanical ventilatory support. We retrospectively analysed the charts of 11 total artificial heart patients who received percutaneous dilatational tracheostomy. We focused on early and late complications. We observed no major complications and no procedure-related deaths. Early minor complications included venous oozing (45.4%) and one case of local infection. Late complications, including subglottic stenosis, stomal infection or infections of the lower respiratory tract, were not observed. In conclusion, percutaneous dilatational tracheostomy in total artificial heart patients is safe. Considering the well-known benefits of early tracheotomy over prolonged translaryngeal intubation, we advocate early timing of therapy in cases of prolonged mechanical ventilation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

The effects of total ankle replacement on ankle joint mechanics during walking

Directory of Open Access Journals (Sweden)

Henry Wang

2017-09-01

Conclusion: Three months after surgeries, the STAA patients experienced improvements in ankle function and gait parameters. The STAA ankle demonstrated improved ankle mechanics during daily activities such as walking.

"It's Totally Destroyed Our Life": Exploring the Pathways and Mechanisms Between Precarious Employment and Health and Well-being Among Immigrant Men and Women in Toronto.

Science.gov (United States)

Premji, Stephanie

2018-01-01

Precarious employment is rapidly growing, but qualitative data on pathways to and mechanisms for health and well-being is lacking. This article describes the cumulative and intersecting micro-level pathways and mechanisms between precarious employment and health among immigrant men and women in Toronto. It draws on semi-structured interviews conducted in 2014 with 15 women and 12 men from 11 countries of origin. The article describes how precarious employment, conceptualized by workers as encompassing powerlessness, economic insecurity, work for multiple employers, nonstandard and unpredictable schedules, hazardous working conditions, and lack of benefits and protections, negatively impacts workers' physical and mental health as well as that of their spouses or partners and children. It documents pathways to health and well-being, including stress, material and social deprivation, and exposure to hazards, as well as commuting difficulties and childcare challenges. Throughout, gender and migration are shown to influence experiences of work and health. The findings draw attention to dimensions of precarity and pathways to health that are not always highlighted in research and discourse on precarious employment and provide valuable insights into the vicious circle of precarious employment and health.

Effect of cryogenic treatment on microstructure, mechanical and wear behaviors of AISI H13 hot work tool steel

Science.gov (United States)

Koneshlou, Mahdi; Meshinchi Asl, Kaveh; Khomamizadeh, Farzad

2011-01-01

This paper focuses on the effects of low temperature (subzero) treatments on microstructure and mechanical properties of H13 hot work tool steel. Cryogenic treatment at -72 °C and deep cryogenic treatment at -196 °C were applied and it was found that by applying the subzero treatments, the retained austenite was transformed to martensite. As the temperature was decreased more retained austenite was transformed to martensite and it also led to smaller and more uniform martensite laths distributed in the microstructure. The deep cryogenic treatment also resulted in precipitation of more uniform and very fine carbide particles. The microstructural modification resulted in a significant improvement on the mechanical properties of the H13 tool steel.

Total quality drives nuclear plant improvements

International Nuclear Information System (INIS)

Richey, R.B.

1991-01-01

Total quality (TQ) at Carolina Power and Light (CP and L) is fulfilling a 1985 vision of Sherwood H. Smith, Jr., CP and L's chairman, president, and chief executive officer. The TQ concept has provided a way for employees to align their creative energies toward meeting the business needs of the company. Throughout CP and L, TQ has been recognized as the vehicle for reducing operating costs and improving customer satisfaction. Within the nuclear organization, application of the TQ process has helped to improve communications, resolve challenges, and provide more consistent work practices among CP and L's three nuclear plants. Total quality was introduced from the top down, with initial benefits coming from team interactions. Senior management at CP and L defined the corporate expectations and outlined the training requirements for implementing TQ. Management staffs at each organizational level became steering committees for TQ team activities within their departments. Teams of employees most knowledgeable about a given work area were empowered to solve problems or overcome obstacles related to that work area. Employees learned to become better team players and to appreciate the quality of decisions reached through group consensus. Now, formalized methods that started TQ are becoming part of the day-to-day work ethic

Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine

International Nuclear Information System (INIS)

Fajar, D M; Khotimah, S N; Khairurrijal

2016-01-01

A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine. (paper)

Thermodynamic and Mechanical Analysis of a Thermomagnetic Rotary Engine

Science.gov (United States)

Fajar, D. M.; Khotimah, S. N.; Khairurrijal

2016-08-01

A heat engine in magnetic system had three thermodynamic coordinates: magnetic intensity ℋ, total magnetization ℳ, and temperature T, where the first two of them are respectively analogous to that of gaseous system: pressure P and volume V. Consequently, Carnot cycle that constitutes the principle of a heat engine in gaseous system is also valid on that in magnetic system. A thermomagnetic rotary engine is one model of it that was designed in the form of a ferromagnetic wheel that can rotates because of magnetization change at Curie temperature. The study is aimed to describe the thermodynamic and mechanical analysis of a thermomagnetic rotary engine and calculate the efficiencies. In thermodynamic view, the ideal processes are isothermal demagnetization, adiabatic demagnetization, isothermal magnetization, and adiabatic magnetization. The values of thermodynamic efficiency depend on temperature difference between hot and cold reservoir. In mechanical view, a rotational work is determined through calculation of moment of inertia and average angular speed. The value of mechanical efficiency is calculated from ratio between rotational work and heat received by system. The study also obtains exergetic efficiency that states the performance quality of the engine.

Comparative exergy analyses of Jatropha curcas oil extraction methods: Solvent and mechanical extraction processes

International Nuclear Information System (INIS)

Ofori-Boateng, Cynthia; Keat Teong, Lee; JitKang, Lim

2012-01-01

Highlights: ► Exergy analysis detects locations of resource degradation within a process. ► Solvent extraction is six times exergetically destructive than mechanical extraction. ► Mechanical extraction of jatropha oil is 95.93% exergetically efficient. ► Solvent extraction of jatropha oil is 79.35% exergetically efficient. ► Exergy analysis of oil extraction processes allow room for improvements. - Abstract: Vegetable oil extraction processes are found to be energy intensive. Thermodynamically, any energy intensive process is considered to degrade the most useful part of energy that is available to produce work. This study uses literature values to compare the efficiencies and degradation of the useful energy within Jatropha curcas oil during oil extraction taking into account solvent and mechanical extraction methods. According to this study, J. curcas seeds on processing into J. curcas oil is upgraded with mechanical extraction but degraded with solvent extraction processes. For mechanical extraction, the total internal exergy destroyed is 3006 MJ which is about six times less than that for solvent extraction (18,072 MJ) for 1 ton J. curcas oil produced. The pretreatment processes of the J. curcas seeds recorded a total internal exergy destructions of 5768 MJ accounting for 24% of the total internal exergy destroyed for solvent extraction processes and 66% for mechanical extraction. The exergetic efficiencies recorded are 79.35% and 95.93% for solvent and mechanical extraction processes of J. curcas oil respectively. Hence, mechanical oil extraction processes are exergetically efficient than solvent extraction processes. Possible improvement methods are also elaborated in this study.

Determination of capacity of single-toggle jaw crusher, taking into account parameters of kinematics of its working mechanism

Science.gov (United States)

Golikov, N. S.; Timofeev, I. P.

2018-05-01

Efficiency increase of jaw crushers makes the foundation of rational kinematics and stiffening of the elements of the machine possible. Foundation of rational kinematics includes establishment of connection between operation mode parameters of the crusher and its technical characteristics. The main purpose of this research is just to establish such a connection. Therefore this article shows analytical procedure of getting connection between operation mode parameters of the crusher and its capacity. Theoretical, empirical and semi-empirical methods of capacity determination of a single-toggle jaw crusher are given, taking into account physico-mechanical properties of crushed material and kinematics of the working mechanism. When developing a mathematical model, the method of closed vector polygons by V. A. Zinoviev was used. The expressions obtained in the article give an opportunity to solve important scientific and technical problems, connected with finding the rational kinematics of the jaw crusher mechanism, carrying out a comparative assessment of different crushers and giving the recommendations about updating the available jaw crushers.

Implantation of total body irradiation in radiotherapy

International Nuclear Information System (INIS)

Habitzreuter, Angela Beatriz

2010-01-01

Before implementing a treatment technique, the characteristics of the beam under irradiation conditions must be well acknowledged and studied. Each one of the parameters used to calculate the dose has to be measured and validated before its utilization in clinical practice. This is particularly necessary when dealing with special techniques. In this work, all necessary parameters and measurements are described for the total body irradiation implementation in facilities designed for conventional treatments that make use of unconventional geometries to generate desired enlarged field sizes. Furthermore, this work presents commissioning data of this modality at Hospital das Clinicas of Sao Paulo using comparison of three detectors types for measurements of entrance dose during total body irradiation treatment. (author)

Work-related basic need satisfaction as a predictor of work ...

African Journals Online (AJOL)

This study examines the relationship between work-related basic need satisfaction and work engagement. Data were obtained from a total of ..... relatedness need exerted positive and significant impact on ... recruitment, budget, student admission, educational forms and .... from potential customers in Northern Cyprus. Acta.

Mechanism design: theory and application to welfare-to-work programs

NARCIS (Netherlands)

Onderstal, S.

2008-01-01

In October 2007, Leonid Hurwicz , Eric Maskin, and Roger Myerson won the Nobel Prize in Economic Sciences "for having laid the foundations of mechanism design theory". My aim is to give you a flavor of what mechanism design theory is and how we can apply it in practice. More in particular, I will

Mechanics

CERN Document Server

Hartog, J P Den

1961-01-01

First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

Part-Time Work and Work Norms in the Netherlands

NARCIS (Netherlands)

Wielers, Rudi; Raven, Dennis

We argue that in the Netherlands, due to the growth of part-time work, work norms have declined. The mechanism behind this norm change is in the changed organization of family life. The increased labour market participation of women has put the traditional organization of family life under pressure.

Total approach is a must for small and medium enterprises to attain sustainable working conditions and environment, with special reference to Bali, Indonesia.

Science.gov (United States)

Manuaba, Adnyana

2006-01-01

Attention and assistance to enhance the role of small and medium scale enterprises (SMEs) by the government is more emphasized due to the success of SMEs in earning significant amount of foreign currency when Indonesia had to face economical crisis in 1997. This policy has been highly recognized again since the bombing tragedy in 2002; with the excellent evidence to show how important SMEs is in helping and maintaining the economic development of Bali. But in the implementation the assistance needs to be remanaged again in a more proper and appropriate way to attain the ultimate goals. The three economic potentials, agriculture in broad sense, tourism and SMEs (cottage industry included), must be developed in harmony, interdependence, support and complementary each other, if possible as synergist to obtain sustainable development of Bali. While assistance to SMEs must be done in a more coordinated way among the government technical offices, universities, NGOs, banking, and other social community institutions. By doing so, there would be no duplication or gap, nor creation of new disadvantageous problems. It could be in form of ergonomics, occupational health and safety impacts and problems in particular, and in adverse working conditions and environment in general. Therefore it is a must at this moment to carry out total approach in helping SMEs, by integrating the effort to improve their working conditions and environment, built-in within the effort to enhance SMEs'quality of life through economic assistance. In this process a total approach through SHIP approach and Appropriate Technology intervention must be done wisely and timely. By so doing, SMEs'sustainable working conditions and environment shall be attained.

The interior working mechanism and temperature characteristics of a fluid based micro-vibration isolator

Science.gov (United States)

Wang, Jie; Zhao, Shougen; Wu, Dafang; Jing, Xingjian

2016-01-01

Micro-vibration isolation is a hot topic in spacecraft vibration control, and fluid based vibration isolators alternatively provide a good and reliable solution to this challenging issue. In this paper, a novel fluid based micro-vibration isolator (FBMVI) is investigated. According to its inherent working principle and deformation pattern, the generation mechanisms of the damping and stiffness characteristics are derived, which are nonlinear functions of the environmental temperature. Then a lumped parameter model which is expressed by the physical design parameters (PDPs) is constructed, and the corresponding performance objective indices (POIs) are also obtained by applying the equivalence of mechanical impedance. Based on the finite element analysis of the internal damping component, a single variable method is further adopted to carry out the parametric study, and the influences of each PDP on the POIs are analyzed in details. Finally, experiments are conducted to identify the variation of fluid bulk modulus with the outside environmental temperature, and to validate the performance of the isolator under different temperature environments. The tested results show great consistence compared with the predicted tendencies of the parametric study. The results of this study can provide a very useful insight into and/or an important guidance for the design and application of this type of FBMVIs in engineering practice.

Suppression of no-longer relevant information in Working Memory: An alpha-power related mechanism?

Science.gov (United States)

Poch, Claudia; Valdivia, María; Capilla, Almudena; Hinojosa, José Antonio; Campo, Pablo

2018-03-27

Selective attention can enhance Working Memory (WM) performance by selecting relevant information, while preventing distracting items from encoding or from further maintenance. Alpha oscillatory modulations are a correlate of visuospatial attention. Specifically, an enhancement of alpha power is observed in the ipsilateral posterior cortex to the locus of attention, along with a suppression in the contralateral hemisphere. An influential model proposes that the alpha enhancement is functionally related to the suppression of information. However, whether ipsilateral alpha power represents a mechanism through which no longer relevant WM representations are inhibited has yet not been explored. Here we examined whether the amount of distractors to be suppressed during WM maintenance is functionally related to alpha power lateralized activity. We measure EEG activity while participants (N = 36) performed a retro-cue task in which the WM load was varied across the relevant/irrelevant post-cue hemifield. We found that alpha activity was lateralized respect to the locus of attention, but did not track post-cue irrelevant load. Additionally, non-lateralized alpha activity increased with post-cue relevant load. We propose that alpha lateralization associated to retro-cuing might be related to a general orienting mechanism toward relevant representation. Copyright © 2018 Elsevier B.V. All rights reserved.

On the problem of technological innovations in driving preparatory workings in thin coal seams

Energy Technology Data Exchange (ETDEWEB)

Peknik, J

1980-03-01

Possibilities of mechanizing preparation of thin coal seams for longwall mining are discussed. Until now preparatory workings in the Ostrava Karvina coal region have been driven mainly by manual work or blasting. Tables show the total length of preparatory workings driven in the period 1973-1978 and the average advance of preparatory working per day and per shift. Factors influencing mechanization of preparatory working drivage are: geological disturbances, angle of seam inclination and its changes, thickness of the seam and strength of coal. Some types of mining machines which can be used for driving preparatory workings in thin, horizontal and inclined coal seams and produced in the USSR and United Kingdom are reviewed. Two sets of machines used in coal seams inclined up to 18 or 20 degrees are presented: KN produced in the USSR and 'In seam Miner' produced by the Dosco firm in the UK. Parameters of both machines are compared. The following Soviet machines for driving preparatory workings in inclined seams are also reviewed: 2 KNP (slope 45-80 degrees), KMD-72 (slope 45-80 degrees, height of the seam 0.6 m to 1.2 m), MRS-2 (slope 45-90 degrees, height of the seam 0.55 m to 1.0 m). (7 refs.) (In Czech)

Effects of LaB{sub 6} additions on the microstructure and mechanical properties of a sintered and hot worked P/M Ti alloy

Energy Technology Data Exchange (ETDEWEB)

Lou, Jia; Gabbitas, Brian, E-mail: briang@waikato.ac.nz; Yang, Fei; Raynova, Stella; Lu, Huiyang

2016-07-25

A trace amount of LaB{sub 6} powder was added to P/M Ti and Ti–6Al–4V alloy to improve mechanical properties and refine the microstructure. After sintering, TiB whiskers and La{sub 2}O{sub 3} dispersoids had formed in the microstructure. In a CP Ti alloy, the generation of secondary phases leads to a much refined microstructure, but the alignment of TiB whiskers led to a variation in mechanical properties. Open die forging (ODF) or powder compact extrusion (PCE) was carried out on sintered Ti–6Al–4V alloy to further improve the mechanical properties. This caused severe deformation and re-alignment of the TiB whiskers. Comparing the properties of hot worked Ti–6Al–4V alloy and Ti–6Al–4V alloy with boron additions, an addition of LaB{sub 6} leads to slightly lower strength but gives significant better ductility. - Highlights: • LaB{sub 6} powder was added to sintered and hot worked Ti and Ti–6Al–4V alloy. • TiB whiskers and La{sub 2}O{sub 3} dispersoids formed in the microstructure. • Different alignments of TiB{sub w} led to a variation in mechanical properties. • Hot working caused severe deformation and re-alignment of TiB{sub w}. • An addition of LaB{sub 6} is better than pure boron additions.

The use of synthetic ligaments in the design of an enhanced stability total knee joint replacement.

Science.gov (United States)

Stokes, Michael D; Greene, Brendan C; Pietrykowski, Luke W; Gambon, Taylor M; Bales, Caroline E; DesJardins, John D

2018-03-01

Current total knee replacement designs work to address clinically desired knee stability and range of motion through a balance of retained anatomy and added implant geometry. However, simplified implant geometries such as bearing surfaces, posts, and cams are often used to replace complex ligamentous constraints that are sacrificed during most total knee replacement procedures. This article evaluates a novel total knee replacement design that incorporates synthetic ligaments to enhance the stability of the total knee replacement system. It was hypothesized that by incorporating artificial cruciate ligaments into a total knee replacement design at specific locations and lengths, the stability of the total knee replacement could be significantly altered while maintaining active ranges of motion. The ligament attachment mechanisms used in the design were evaluated using a tensile test, and determined to have a safety factor of three with respect to expected ligamentous loading in vivo. Following initial computational modeling of possible ligament orientations, a physical prototype was constructed to verify the function of the design by performing anterior/posterior drawer tests under physiologic load. Synthetic ligament configurations were found to increase total knee replacement stability up to 94% compared to the no-ligament case, while maintaining total knee replacement flexion range of motion between 0° and 120°, indicating that a total knee replacement that incorporates synthetic ligaments with calibrated location and lengths should be able to significantly enhance and control the kinematic performance of a total knee replacement system.

Modelling and simulation of multi spindle drilling redundant SCARA robot using SolidWorks and MATLAB/SimMechanics

Directory of Open Access Journals (Sweden)

Saravana Mohan Mariappan

2016-01-01

Full Text Available Los robots son sistemas electromecánicos que necesitan enfoque mecatrónico antes de fabricarlos, esto con el fin de reducir el costo de desarrollo. En este trabajo se presenta un nuevo intento de modelado PRRP (prismáticos-revoluto-revoluto-prismático, una configuración redundante SCARA (Brazo robótico articulado de respuesta selectiva, herramienta de perforación milti-eje (MSDT usando el software CAD de SolidWorks y el estudio dinámico con la ayuda de MATLAB/SimMechanics de perforación. Un SCARA con MSDT se utiliza para perforar varios agujeros en las placas de circuito impreso (PCB y la chapa metálica. En este trabajo, el modelo de CAD 3D del robot propuesto se convierte en un diagrama de bloque SimMechanics exportando a MATLAB/SimMechanics segunda generación de tecnología de modelado y simulación. Entonces se realiza una simulación SimMechanics y utilizando su capacidad de detección de movimiento la velocidad de parámetros dinámicos y la torsión del manipulador se observa la estructura del robot variable modificado. Los resultados de la simulación indican un cambio considerable en el rendimiento dinámico para diferentes parámetros de diseño.

Trace of Korean mechanical industry

International Nuclear Information System (INIS)

1996-12-01

This book reports 50 years of Korean mechanical engineers, which includes birth and history, remembrance and future of Korean society of mechanical engineers, current situation and development of mechanical industry such as national industry and 50 years of mechanical industry, track, airline industry, ship and marine engine, a precision instrument, cutting work, casting, welding, plastic working freeze and air handling nuclear power and textile machinery.

Replacement of quartz in cementitious composites using PET particles:A statistical analysis of the physical and mechanical properties

OpenAIRE

Detomi, Anine Cristina; Filho, Sergio Luiz Moni Ribeiro; Panzera, Túlio H C; Schiavon, Marco Antonio; Silva, Vania R V; Scarpa, Fabrizio

2016-01-01

This work investigates the mechanical behavior of cementitious composites (mortar) when quartz inclusions are totally or partially replaced with polyethylene terephthalate (PET) particles. A full factorial design is performed to identify the effect of the water/cement ratio and the range of quartz particles size used in the replacement on the different mechanical and physical parameters (bulk density, apparent porosity, water absorption, oxygen permeability, compressive strength, and modulus ...

Nonverbal working memory of humans and monkeys: rehearsal in the sketchpad?

Science.gov (United States)

Washburn, D. A.; Astur, R. S.; Rumbaugh, D. M. (Principal Investigator)

1998-01-01

Investigations of working memory tend to focus on the retention of verbal information. The present experiments were designed to characterize the active maintenance rehearsal process used in the retention of visuospatial information. Rhesus monkeys (Macaca mulatta; N = 6) were tested as well as humans (total N = 90) because these nonhuman primates have excellent visual working memory but, unlike humans, cannot verbally recode the stimuli to employ verbal rehearsal mechanisms. A series of experiments was conducted using a distractor-task paradigm, a directed forgetting procedure, and a dual-task paradigm. No evidence was found for an active maintenance process for either species. Rather, it appears that information is maintained in the visuospatial sketchpad without active rehearsal.

Unemployment, informal work, precarious employment, child labor, slavery, and health inequalities: pathways and mechanisms.

Science.gov (United States)

Muntaner, Carles; Solar, Orielle; Vanroelen, Christophe; Martínez, José Miguel; Vergara, Montserrat; Santana, Vilma; Castedo, Antía; Kim, Il-Ho; Benach, Joan

2010-01-01

The study explores the pathways and mechanisms of the relation between employment conditions and health inequalities. A significant amount of published research has proved that workers in several risky types of labor--precarious employment, unemployment, informal labor, child and bonded labor--are exposed to behavioral, psychosocial, and physio-pathological pathways leading to physical and mental health problems. Other pathways, linking employment to health inequalities, are closely connected to hazardous working conditions (material and social deprivation, lack of social protection, and job insecurity), excessive demands, and unattainable work effort, with little power and few rewards (in salaries, fringe benefits, or job stability). Differences across countries in the social contexts and types of jobs result in varying pathways, but the general conceptual model suggests that formal and informal power relations between employees and employers can determine health conditions. In addition, welfare state regimes (unionization and employment protection) can increase or decrease the risk of mortality, morbidity, and occupational injury. In a multilevel context, however, these micro- and macro-level pathways have yet to be fully studied, especially in middle- and low-income countries. The authors recommend some future areas of study on the pathways leading to employment-related health inequalities, using worldwide standard definitions of the different forms of labor, authentic data, and a theoretical framework.

Models of Working Memory

National Research Council Canada - National Science Library

Miyake, Akira

1997-01-01

Working memory is a basic cognitive mechanism (or set of mechanisms) that is responsible for keeping track of multiple task related goals and subgoals, or integrating multiple sources of information...

Incidence of shoulder and neck pain in a working population: effect modification between mechanical and psychosocial exposures at work? Results from a one year follow up of the Malmö shoulder and neck study cohort.

Science.gov (United States)

Ostergren, Per-Olof; Hanson, Bertil S; Balogh, Istvan; Ektor-Andersen, John; Isacsson, Agneta; Orbaek, Palle; Winkel, Jörgen; Isacsson, Sven-Olof

2005-09-01

To assess the impact of mechanical exposure and work related psychosocial factors on shoulder and neck pain. A prospective cohort study. 4919 randomly chosen, vocationally active men and women ages 45-65 residing in a Swedish city. Neck and shoulder pain were determined by the standardised Nordic questionnaire. Mechanical exposure was assessed by an index based on 11 items designed and evaluated for shoulder and neck disorders. Work related psychosocial factors were measured by the Karasek and Theorell demand-control instrument. High mechanical exposure was associated with heightened risk for shoulder and neck pain among men and women during follow up. Age adjusted odds ratios (OR) were 2.17 (95% confidence intervals (CI): 1.65, 2.85) and 1.59 (95% CI: 1.22, 2.06), respectively. In women, job strain (high psychological job demands and low job decision latitude) correlated with heightened risk (OR = 1.73, 95% CI: 1.29, 2.31). These risk estimates remained statistically significant when controlled for high mechanical exposure regarding job strain (and vice versa), and for sociodemographic factors. Testing for effect modification between high mechanical exposure and job strain showed them acting synergistically only in women. Job related mechanical exposure in both sexes, and psychosocial factors in women, seem independently of each other to play a part for development of shoulder and neck pain in vocationally active people. The effect of psychosocial factors was more prominent in women, which could be the result of biological factors as well as gender issues. These results suggest that interventions aiming at reducing the occurrence of shoulder and neck pain should include both mechanical and psychosocial factors.

Effect of temperature on the mechanical characteristics of cold-worked steel OKh16N15M3B with active tension and creep

International Nuclear Information System (INIS)

Erasov, V.S.; Konoplenko, V.P.; Pirogov, E.N.

1986-01-01

Steel OKh16N15M3B is used extensively for the manufacture of atomic reactor fuel-element shells. The aim of this work is a study of the mechanical characteristics of this steel cold-worked by 20% with active tension and creep in the temperature range 973-1323 0 K, which is necessary for predicting the behavior of fuel-element shells in critical situations. It is found that above 973 0 K there is active loss of strength for cold-worked steel OKh16N15M3B. Strength characteristics in the region 973-1323 0 K decrease by more than a factor of six. Thermal activation analysis of the plastic deformation process, showing a sharp increase in activation energy above 1073 0 K, suggests a change in the mechanisms of plastic deformation taking place. For active tension and creep the same temperature range is obtained for a marked change in activation energy

Modeling of the cold work stress relieved Zircaloy-4 cladding tubes mechanical behavior under PWR operating conditions

International Nuclear Information System (INIS)

Richard, F.; Delobelle, P.; Leclercq, S.; Bouffioux, P.; Rousselier, G.

2003-01-01

This paper proposes a damaged viscoplastic model to simulate, for different isotherms (320, 350, 380, 400 and 420 degC), the out-of-flux anisotropic mechanical behavior of cold work stress relieved Zircaloy-4 cladding tubes over the fluence range 0-85.1024 nm -2 (E > 1 MeV). The model, identified from uni and biaxial tests conducted at 350 and 400 degC, is validated from tests performed at 320, 380 and 420 degC. This model is able to simulate strain hardening under internal pressure followed by a stress relaxation period (thermal creep), which is representative of a pellet cladding mechanical interaction occurring during a power transient (class 2 incidental condition). Both the integration of a scalar state variable, characterizing the damage caused by a bombardment with neutrons, and the modification of the static recovery law allowed us to simulate the fast neutron flux effect (irradiation creep). (author)

The impact of menopausal symptoms on work ability.

Science.gov (United States)

Geukes, Marije; van Aalst, Mariëlle P; Nauta, Mary C E; Oosterhof, Henk

2012-03-01

Menopause is an important life event that may have a negative influence on quality of life. Work ability, a concept widely used in occupational health, can predict both future impairment and duration of sickness absence. The aim of this study was to examine the impact of menopausal symptoms on work ability. This was a cross-sectional study that used a sample of healthy working Dutch women aged 44 to 60 years. Work ability was measured using the Work Ability Index, and menopausal symptoms were measured using the Greene Climacteric Scale. Stepwise multiple linear regression models were used to examine the relationship between menopausal symptoms and work ability. A total of 208 women were included in this study. There was a significant negative correlation between total Greene Climacteric Scale score and Work Ability Index score. Total Greene Climacteric Scale score predicted 33.8% of the total variance in the Work Ability Index score. Only the psychological and somatic subscales of the Greene Climacteric Scale were significant predictors in multiple linear regression analysis. Together, they accounted for 36.5% of total variance in Work Ability Index score. Menopausal symptoms are negatively associated with work ability and may increase the risk of sickness absence.

Work and minor work contracts

CERN Document Server

1999-01-01

The Work and Minor Work contracts are all of the result-oriented type. The work is specified by CERN and the contractor is given full responsibility for its performance. The contracts are thus very similar to supply contracts. The re-tendering of the existing contracts is almost complete, except for some building maintenance contracts. A new cycle of re-tendering for some activities will be launched in the next twelve months. The total estimated expenditure in the year 2000 for the contracts referred to in this document is 27 750 000 Swiss francs at 1999 prices. The Finance Committee is invited: - to approve the proposed expenditure for the extension of contracts for which the estimated amount for the year 2000 exceeds 750 000 Swiss francs, namely those under references 1, 2, 3, 5, 7, 8, 9 and 23, highlighted in Table I; - to take note that all Work and Minor Work contracts have been tendered since 1 January 1994, except the small contracts shown under references 12 and 16 in Table I; - to take note that the ...

A fracture- mechanics calculation of crack growth rate for a gas turbine blade

International Nuclear Information System (INIS)

Mirzaei, M.; Karimi, R.

2002-01-01

The existence of thermo-mechanical stresses, due to the frequent start-ups and shutdowns of gas turbines. Combined with high working temperatures may cause creep and fatigue failure of the blades. This paper describes a fracture-mechanics life assessment of a gas turbine blade. Initially, the distributions of thermal and mechanical stresses were obtained by using the finite element method. Accordingly; the crack modeling was performed in a high stress region at the suction side surface of the blade. Several crack growth increments were observed and the related crack tip parameters were calculated. Finally; the creep-fatigue crack growth in each cycle was calculated and the total number of start-stop cycles was determined

Analysis of the Almond Harvesting and Hulling Mechanization Process: A Case Study

Directory of Open Access Journals (Sweden)

Simone Pascuzzi

2017-12-01

Full Text Available The aim of this paper is the analysis of the almond harvesting system with a very high level of mechanization frequently used in Apulia for the almond harvesting and hulling process. Several tests were carried out to assess the technical aspects related to the machinery and to the mechanized harvesting system used itself, highlighting their usefulness, limits, and compatibility within the almond cultivation sector. Almonds were very easily separated from the tree, and this circumstance considerably improved the mechanical harvesting operation efficiency even if the total time was mainly affected by the time required to manoeuvre the machine and by the following manual tree beating. The mechanical pick-up from the ground was not effective, with only 30% of the dropped almond collected, which mainly was caused by both the pick-up reel of the machine being unable to approach the almonds dropped near the base of the trunk and the surface condition of the soil being unsuitably arranged for a mechanized pick-up operation. The work times concerning the hulling and screening processes, carried out at the farm, were heavily affected by several manual operations before, during, and after the executed process; nevertheless, the plant work capability varied from 170 to 200 kg/h with two operators.

Catchment Dispersion Mechanisms in an Urban Context

Science.gov (United States)

Gironas, J. A.; Mejia, A.; Rossel, F.; Rinaldo, A.; Rodriguez, F.

2014-12-01

Dispersion mechanisms have been examined in-depth in natural catchments in previous studies. However, these dispersion mechanisms have been studied little in urban catchments, where artificial transport elements and morphological arrangements are expected to modify travel times and mobilize excess rainfall from spatially distributed impervious sites. Thus, these features can modify the variance of the catchment's travel times and hence the total dispersion. This work quantifies the dispersion mechanisms in an urban catchment using the theory of transport by travel times as represented by the Urban Morpho-climatic Instantaneous Unit Hydrograph (U-McIUH) model. This model computes travel times based on kinematic wave theory and accounts explicitly for the path heterogeneities and altered connectivity patterns characteristic of an urban drainage network. The analysis is illustrated using the Aubinière urban catchment (France) as a case study. We found that kinematic dispersion is dominant for small rainfall intensities, whereas geomorphologic dispersion becomes more dominant for larger intensities. The total dispersion scales with the drainage area in a power law fashion. The kinematic dispersion is dominant across spatial scales up to a threshold of approximately 2-3 km2, after which the geomorphologic dispersion becomes more dominant. Overall, overland flow is responsible for most of the dispersion, while conduits tend to counteract the increase of the geomorphologic dispersion with a negative kinematic dispersion. Further studies with other catchments are needed to assess whether the latter is a general feature of urban drainage networks.

Total lymphoid irradiation

International Nuclear Information System (INIS)

Anon.

1980-01-01

An outline review notes recent work on total lymphoid irradiation (TLI) as a means of preparing patients for grafts and particularly for bone-marrow transplantation. T.L.I. has proved immunosuppressive in rats, mice, dogs, monkeys and baboons; when given before bone-marrow transplantation, engraftment took place without, or with delayed rejection or graft-versus-host disease. Work with mice has indicated that the thymus needs to be included within the irradiation field, since screening of the thymus reduced skin-graft survival from 50 to 18 days, though irradiation of the thymus alone has proved ineffective. A more lasting tolerance has been observed when T.L.I. is followed by an injection of donor bone marrow. 50% of mice treated in this way accepted allogenic skin grafts for more than 100 days, the animals proving to be stable chimeras with 50% of their peripheral blood lymphocytes being of donor origin. Experiments of a similar nature with dogs and baboons were not so successful. (U.K.)

TOTAL REWARDS MODEL IN ROMANIAN COMPANIES

Directory of Open Access Journals (Sweden)

Elena-Sabina HODOR

2014-04-01

Full Text Available Total Rewards Management is a subject of major importance for companies, because, by using models for this, firms can achieve their objectives of high performance. In order to analyse a validated total rewards model in Romanian Accounting and Consulting Companies, it is used The WorldatWork Total Rewards Model, which depict what contributes to applicant attraction and employee motivation and retention. Thus, the methodology of the previous survey is adjusted to the local context. The conclusions for the methodological aspects illustrate that the present research involves three strategic steps in order to achieve the objectives presented: the analysis of organizational environment of the companies from the sample, checking if Total Rewards Model proposed in the previous research is applicable for the same romanian companies from the previous survey, the analysing of the differences between results, and, if necessary, the adaptation of the model for Romania.

Mechanisms and neuronal networks involved in reactive and proactive cognitive control of interference in working memory.

Science.gov (United States)

Irlbacher, Kerstin; Kraft, Antje; Kehrer, Stefanie; Brandt, Stephan A

2014-10-01

Cognitive control can be reactive or proactive in nature. Reactive control mechanisms, which support the resolution of interference, start after its onset. Conversely, proactive control involves the anticipation and prevention of interference prior to its occurrence. The interrelation of both types of cognitive control is currently under debate: Are they mediated by different neuronal networks? Or are there neuronal structures that have the potential to act in a proactive as well as in a reactive manner? This review illustrates the way in which integrating knowledge gathered from behavioral studies, functional imaging, and human electroencephalography proves useful in answering these questions. We focus on studies that investigate interference resolution at the level of working memory representations. In summary, different mechanisms are instrumental in supporting reactive and proactive control. Distinct neuronal networks are involved, though some brain regions, especially pre-SMA, possess functions that are relevant to both control modes. Therefore, activation of these brain areas could be observed in reactive, as well as proactive control, but at different times during information processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

How Do You Take Time? Work-Life Balance Policies versus Neoliberal, Social and Cultural Incentive Mechanisms in Icelandic Higher Education

Science.gov (United States)

Smidt, Thomas Brorsen; Pétursdóttir, Gyða Margrét; Einarsdóttir, Þorgerður

2017-01-01

It is suggested that the realization of work-life balance policies at the University of Iceland is compromised by an emphasis on neoliberal notions of growth and performance measurements in the form of new public management strategies. This is sustained by overt and covert incentive mechanisms, which in turn create a range of different gendered…

Total and available metal contents in sediments by synchrotron radiation total reflection X-ray fluorescence

International Nuclear Information System (INIS)

Moreira, Silvana; Sobrinho, Gilmar A.; Jesus, Edgar F.O. de; Lopes, Ricardo T.

2002-01-01

In this work the total and available contents of Al, Si, Cl, K, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Ba, Ce and Pb in sediments from river Atibaia were determined by Synchrotron Radiation Total Reflection X-Ray Fluorescence technique. The detection limits for K series varies from 200 ng.mL -1 for Al to 2 ng.mL -1 for Zn while for L series the value varies from 20 ng.mL -1 for Ba to 10 ng.mL -1 for Pb. The samples were submitted to two different processes, in order to obtain the total and biological available metal contents. The information about metal content is a important parameter for a correct evaluation about the hydrologic cycle in Piracicaba basin. All the measure were carried out at the National Synchrotron Light Laboratory, Campinas, SP, Brazil, using a white beam for excitation. (author)

Nursing Students' Perceptions of the Transition to Shift Work: A Total Worker Health Perspective.

Science.gov (United States)

Postma, Julie; Tuell, Erica; James, Lois; Graves, Janessa M; Butterfield, Patricia

2017-11-01

Nursing students make an abrupt transition from traditional classes to clinical rotations and shift work. Little is known about students' sleep, sleep disturbances, and safe practice behaviors during this critical phase of professional development. The purpose of this study was to identify nursing students' perceptions of problems and potential solutions related to shift work and long work hours. This qualitative, descriptive study used two nursing student focus groups which engaged in a two-round participatory process aimed at framing future interventions. Participants identified problems and solutions related to personal and workplace well-being. Findings will inform undergraduate curricular revisions, and hospital hiring and managerial practices.

Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

Science.gov (United States)

Wang, Yanan; Qin, Qing-Hua

2010-03-01

The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.

Oculomotor preparation as a rehearsal mechanism in spatial working memory.

Science.gov (United States)

Pearson, David G; Ball, Keira; Smith, Daniel T

2014-09-01

There is little consensus regarding the specific processes responsible for encoding, maintenance, and retrieval of information in visuo-spatial working memory (VSWM). One influential theory is that VSWM may involve activation of the eye-movement (oculomotor) system. In this study we experimentally prevented healthy participants from planning or executing saccadic eye-movements during the encoding, maintenance, and retrieval stages of visual and spatial working memory tasks. Participants experienced a significant reduction in spatial memory span only when oculomotor preparation was prevented during encoding or maintenance. In contrast there was no reduction when oculomotor preparation was prevented only during retrieval. These results show that (a) involvement of the oculomotor system is necessary for optimal maintenance of directly-indicated locations in spatial working memory and (b) oculomotor preparation is not necessary during retrieval from spatial working memory. We propose that this study is the first to unambiguously demonstrate that the oculomotor system contributes to the maintenance of spatial locations in working memory independently from the involvement of covert attention. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Mechanical engineers' handbook, materials and engineering mechanics

CERN Document Server

Kutz, Myer

2015-01-01

Full coverage of materials and mechanical design inengineering Mechanical Engineers' Handbook, Fourth Edition provides aquick guide to specialized areas you may encounter in your work,giving you access to the basics of each and pointing you towardtrusted resources for further reading, if needed. The accessibleinformation inside offers discussions, examples, and analyses ofthe topics covered. This first volume covers materials and mechanical design, givingyou accessible and in-depth access to the most common topics you'llencounter in the discipline: carbon and alloy steels, stainlesssteels, a

Technical isomorphism at work : ERP-embedded similarity-enhancing mechanisms

NARCIS (Netherlands)

Batenburg, Ronald; Benders, Jos; van der Blonk, Heico

2008-01-01

Purpose - The purpose of this paper is to discuss the mechanisms inducing a user organization to conform with enterprise resource planning (ERP)-embedded organizational logics and accompanying implementation procedures. Design/methodology/approach - Based around the notion of technical isomorphism,

Analysis of the total system life cycle cost for the Civilian Radioactive Waste Management Program: executive summary

International Nuclear Information System (INIS)

1985-04-01

The total-system life-cycle cost (TSLCC) analysis for the Department of Energy's Civilian Radioactive Waste Management Progrram is an ongoing activity that helps determine whether the revenue-producing mechanism established by the Nuclear Waste Policy Act of 1982 is sufficient to cover the cost of the program. This report is an input into the third evaluation of the adequacy of the fee. The total-system cost for the reference waste-management program in this analysis is estimated to be 24 to 30 billion (1984) dollars. For the sensitivity cases studied in this report, the costs could be as high as 35 billion dollars and as low as 21 billion dollars. Because factors like repository location, the quantity of waste generated, transportation-cask technology, and repository startup dates exert substantial impacts on total-system costs, there are several tradeoffs between these factors, and these tradeoffs can greatly influence the total cost of the program. The total-system cost for the reference program described in this report is higher by 3 to 5 billion dollars, or 15 to 20%, than the cost for the reference program of the TSLCC analysis of April 1984. More than two-thirds of this increase is in the cost of repository construction and operation. These repository costs have increased because of changing design concepts, different assumptions about the effort required to perform the necessary activities, and a change in the source data on which the earlier analysis was based. Development and evaluation costs have similarly increased because of a net addition to the work content. Transportation costs have increased because of different assumptions about repository locations and several characteristics of the transportation system. It is expected that the estimates of total-system costs will continue to change in response to both an evolving program strategy and better definition of the work required to achieve the program objectives

Coping strategies used by nurses before, during and after work to deal with work stress: a literature review

Directory of Open Access Journals (Sweden)

Georgios Manomenidis

2017-03-01

Full Text Available The nursing profession is characterized by high levels of work stress and serious associated health problems. The aim of the present study was to explore the strategies nurses employ before, during and after work to cope with every day work stress. The literature review indicated that nurses use mechanisms which at the beginning of shift work as preparation mechanisms, during work as stress controllers and after the end of it as an opportunity for nursing staff’s emotional recovery. In terms of effectiveness, the use of stress coping mechanisms not only reduces job burnout but also increases nurses’ job satisfaction and wellbeing. However, evidence show that their duration is short and their effectiveness may be limited. Changes mainly in organizational level are required to create a more positive working environment and advocate for nurses’ good level of health and wellbeing.

Universal Expression of Efficiency at Maximum Power: A Quantum-Mechanical Brayton Engine Working with a Single Particle Confined in a Power-Law Trap

International Nuclear Information System (INIS)

Ye Zhuo-Lin; Li Wei-Sheng; Lai Yi-Ming; He Ji-Zhou; Wang Jian-Hui

2015-01-01

We propose a quantum-mechanical Brayton engine model that works between two superposed states, employing a single particle confined in an arbitrary power-law trap as the working substance. Applying the superposition principle, we obtain the explicit expressions of the power and efficiency, and find that the efficiency at maximum power is bounded from above by the function: η_+ = θ/(θ + 1), with θ being a potential-dependent exponent. (paper)

An investigation into the effects of conventional heat treatments on mechanical characteristics of new hot working tool steel

Science.gov (United States)

Fares, M. L.; Athmani, M.; Khelfaoui, Y.; Khettache, A.

2012-02-01

The effects of conventional heat treatments, i.e. quenching and tempering, on the mechanical characteristics of non standard hot work tool steel, close to either AISI-H11/H13 are investigated. The major elemental composition differences are in carbon, silicon and vanadium. The objective of the carried heat treatments is to obtain an efficient tool performance in terms of hardness, wear resistance and mechanical strength. Experimental results allow an explanation of the surface properties depending mainly on both chemical composition and optimised preheating parameters. After austenitizing at 1050 °C for 15 min, the as-quenched steel in oil bath exhibited the fully martensitic structure (without bainite) connected to a small fraction of retained austenite and complex carbides mainly of M23C6 type. Twice tempering at 500 °C and 600 °C resulted in initiating the precipitation processes and the secondary hardness effect. As a result, carbide content amounted to 3% while the retained austenite content decreased to 0%. Accordingly, the required mechanical properties in terms of hardness and wear are fulfilled and are adequately favourable in handling both shocks and pressures for the expected tool life. Induced microstructures are revealed using optical and scanning electron microscopes. Phase compositions are assessed by means of X-ray diffraction technique while mechanical characteristics are investigated based on hardness and abrasive wear standard tests.

Total and respirable dust exposures among carpenters and demolition workers during indoor work in Denmark

DEFF Research Database (Denmark)

Kirkeskov, Lilli; Hanskov, Dorte Jessing Agerby; Brauer, Charlotte

2016-01-01

BACKGROUND: Within the construction industry the risk of lung disorders depends on the specific professions probably due to variations in the levels of dust exposure, and with dust levels depending on the work task and job function. We do not know the extent of exposure in the different professions...... was 3.90 (95 % confidence interval 1.13-13.5) mg/m(3). Dust exposure varied depending on work task for both professions. The dustiest work occurred during demolition, especially when it was done manually. Only few workers used personal respiratory protection and only while performing the dustiest work...... or the variation between the different work tasks. The purpose of this study was therefore to assess if there were differences in dust exposure between carpenters and demolition workers who were expected to have low and high dust exposure, respectively. METHODS: Through interviews of key persons...

Total Monte-Carlo method applied to the assessment of uncertainties in a reactivity-initiated accident

Energy Technology Data Exchange (ETDEWEB)

Cruz, D.F. da; Rochman, D.; Koning, A.J. [Nuclear Research and Consultancy Group NRG, Petten (Netherlands)

2014-07-01

The Total Monte-Carlo (TMC) method has been applied extensively since 2008 to propagate the uncertainties in nuclear data for reactor parameters and fuel inventory, and for several types of advanced nuclear systems. The analyses have been performed considering different levels of complexity, ranging from a single fuel rod to a full 3-D reactor core at steady-state. The current work applies the TMC method for a full 3-D pressurized water reactor core model under steady-state and transient conditions, considering thermal-hydraulic feedback. As a transient scenario the study focused on a reactivity-initiated accident, namely a control rod ejection accident initiated by a mechanical failure of the control rod drive mechanism. The uncertainties on the main reactor parameters due to variations in nuclear data for the isotopes {sup 235},{sup 238}U, {sup 239}Pu and thermal scattering data for {sup 1}H in water were quantified. (author)

Work Time Control and Sleep Disturbances

DEFF Research Database (Denmark)

Salo, Paula; Ala-Mursula, Leena; Rod, Naja Hulvej

2014-01-01

OBJECTIVES: Employee control over work times has been associated with favorable psychosocial and health-related outcomes, but the evidence regarding sleep quality remains inconclusive. We examined cross-sectional and prospective associations between work time control and sleep disturbances...... in a large working population, taking into account total hours worked. METHODS: The data were from a full-panel longitudinal cohort study of Finnish public sector employees who responded to questions on work time control and sleep disturbances in years 2000-2001, 2004-2005, 2008-2009, and 2012. The analysis....... RESULTS: Consistently in both cross-sectional and longitudinal models, less control over work time was associated with greater sleep disturbances in the total population and among those working normal 40-hour weeks. Among participants working more than 40 hours a week, work time that was both very high...

Assessment of work engagement among dentists in Hyderabad.

Science.gov (United States)

Mukkavilli, Madhuri; Kulkarni, Suhas; Doshi, Dolar; Reddy, Srikanth; Reddy, Padma; Reddy, Sahithi

2017-01-01

Work engagement has been conceptualized as a relatively stable phenomenon, partly explained by the presence of specific job and organizational characteristics. Work engagement is important to the dental workforce worldwide, and the lack of it has been known to cause burnout. Positivity among dentists is essential as it is directly proportional to the patient's satisfaction towards the dental care. To assess work engagement among dentists in the city of Hyderabad, India. A cross-sectional questionnaire study was conducted to assess work engagement among dentists enrolled with the local branch of the Indian Dental Association in the city of Hyderabad, India. The shortened form of the Utrecht Work Engagement Scale (UWES-9) questionnaire was employed for the assessment. The mean scores of total work engagement and its domains based on gender and educational qualifications were estimated using Student t- test. A total of 371 subjects participated in the study. Females reported higher mean scores than males for total work (p = 0.40) and its dimensions (Vigor; p = 0.23, Dedication; p = 0.53, Absorption; p = 0.69). Dentists with Master's degree had higher mean scores not only in the total work, but also in its dimensions. (p = 0.01). The present study reported that females had higher mean scores of total work engagement and its individual domains. In comparison with a Bachelor's degree, having a Master's degree enhanced work engagement among dentists in Hyderabad, India.

Work-Family Conflict and Work-Related Attitude: The Mediating Effects of Stress Reactions

OpenAIRE

Siti Aisyah Binti Panatik; Siti Khadijah Binti Zainal Badri; Azizah Binti Rajab; Rosman Bin Mohd. Yusof

2012-01-01

This study aims to investigate the relationship between work-family conflict (i.e.work-to-family and family-to-work) and work-related attitudes (i.e. job satisfaction,affective commitment and turnover intentions) among academician in Malaysia.Mediationeffects of stress reactionswhich arebehavioral stress, somatic stress andcognitive stresswere also tested. A survey method using questionnaire was utilizedto obtain the data. A total of 267 respondents were participated, giving...

Continuum Mechanics

CERN Document Server

Romano, Antonio

2010-01-01

This book offers a broad overview of the potential of continuum mechanics to describe a wide range of macroscopic phenomena in real-world problems. Building on the fundamentals presented in the authors' previous book, Continuum Mechanics using Mathematica(R), this new work explores interesting models of continuum mechanics, with an emphasis on exploring the flexibility of their applications in a wide variety of fields.Specific topics, which have been chosen to show the power of continuum mechanics to characterize the experimental behavior of real phenomena, include: * various aspects of nonlin

Comparing of mechanical behavior and microstructure of continuous cast and hot worked Cu Zn 40 Al 1 alloy

International Nuclear Information System (INIS)

Ebrahimzadeh, I.; Akbari, G. H.

2007-01-01

The performance of components produced by conventional route of a thermo mechanical process and those produced by continuous casting is interesting from different aspects of economy and technology. The performance of products in their service depends on their properties which are strongly influenced by production routes. In the present work the hardness, tensile and tensile-impact behaviors of Cu Zn 40 Al 1 alloys produced by continuous casting and extrusion were investigated. Micro structural features and fracture surfaces were studied by optical and scanning electron microscopy. Results showed that wrought samples exhibited higher absorbed energy than those of continuous cast samples. Reduction of impact velocity led to a higher absorbed energy in all samples. A systematic and meaningful relationship was observed between micro structural features and mechanical properties such as hardness, yield stress and ultimate tensile strength. Fractography investigations showed that fracture occurred with dimple formation in all cases

COPING MECHANISM OF CAREER WOMEN WITH BREAST CANCER

Directory of Open Access Journals (Sweden)

Rosnani Rosnani

2017-06-01

Full Text Available Introduction: Patients with cancer may experience psychological disorders such as depression, anxiety, anger, helplessness, and unappreciated, so in certain situations require defense mechanisms (coping mechanism to oppose or resist feelings of anxiety, fear or stress that haunt her. The aim of this study was to know the coping mechanism of career women with breast cancer reviewed by phenomenology in Palembang 2016. Method: Type of this study was a qualitative study with a phenomenological approach. Total samples were 8 participants with inclusion criteria: career women, productive age range, health physic and physiologic. Independent variable was a coping mechanism, and the dependent variable was breast cancer. The instrument used the voice recorder, and interview guides. Data analyze used verbatim transcript with credibility, dependability, and confirmability. Result: The results showed that working women who have breast cancer have a coping strategy that is adjusted to the psychological condition and physical reactions of the therapy in progress. Psychologically, the coping mechanism is in the form of rejecting, drawing closer to Allah SWT, seeking the opinion of other health workers, discussing conditions with spouse and family, seeking alternative treatment and asking for doctor's direction. The coping mechanism of the body's reaction to therapy is done by taking medicine according to the rules and remember Allah SWT. Conclusions: Need the support of the coping mechanism in patients with breast cancer and nursing care approach with the pattern of coping mechanisms with the involvement of the family.

Mechanisms of Breast Cancer in Shift Workers: DNA Methylation in Five Core Circadian Genes in Nurses Working Night Shifts.

Science.gov (United States)

Samulin Erdem, Johanna; Skare, Øivind; Petersen-Øverleir, Marte; Notø, Heidi Ødegaard; Lie, Jenny-Anne S; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-01-01

Shift work has been suggested to be associated with breast cancer risk, and circadian disruption in shift workers is hypothesized as one of the mechanisms of increased cancer risk. There is, however, insufficient molecular evidence supporting this hypothesis. Using the quantitative methodology of pyrosequencing, epigenetic changes in 5-methyl cytosine (5mC) in five circadian genes CLOCK , BMAL1 , CRY1, PER1 and PER2 in female nurses working night shift work (278 breast cancer cases, 280 controls) were analyzed. In breast cancer cases, a medium exposure to night work was associated with increased methylation levels of the CLOCK (p=0.050), BMAL1 (p=0.001) and CRY1 (p=0.040) genes, compared with controls. Within the cases, analysis of the effects of shift work on the methylation patterns showed that methylation of CRY1 was lower in those who had worked night shift and had a high exposure (p=0.006) compared with cases that had worked only days. For cases with a medium exposure to night work, an increase in BMAL1 (p=0.003) and PER1 (p=0.035) methylation was observed compared with day working (unexposed) cases. The methylation levels of the five core circadian genes were also analyzed in relation to the estrogen and progesterone receptors status of the tumors in the cases, and no correlations were observed. Furthermore, nineteen polymorphisms in the five circadian genes were assessed for their effects on the methylation levels of the respective genes, but no associations were found. In summary, our data suggest that epigenetic regulation of CLOCK , BMAL1, CRY1 and PER1 may contribute to breast cancer in shift workers.

Statistical mechanics in JINR

International Nuclear Information System (INIS)

Tonchev, N.; Shumovskij, A.S.

1986-01-01

The history of investigations, conducted at the JINR in the field of statistical mechanics, beginning with the fundamental works by Bogolyubov N.N. on superconductivity microscopic theory is presented. Ideas, introduced in these works and methods developed in them, have largely determined the ways for developing statistical mechanics in the JINR and Hartree-Fock-Bogolyubov variational principle has become an important method of the modern nucleus theory. A brief review of the main achievements, connected with the development of statistical mechanics methods and their application in different fields of physical science is given

Revitalizing Space Operations through Total Quality Management

Science.gov (United States)

Baylis, William T.

1995-01-01

The purpose of this paper is to show the reader what total quality management (TQM) is and how to apply TQM in the space systems and management arena. TQM is easily understood, can be implemented in any type of business organization, and works.

Metabolic and mechanical aspects of foot landing type, forefoot and rearfoot strike, in human running.

Science.gov (United States)

Ardigò, L P; Lafortuna, C; Minetti, A E; Mognoni, P; Saibene, F

1995-09-01

The study was undertaken to assess the metabolic and the mechanical aspects of two different foot strike patterns in running, i.e. forefoot and rearfoot striking (FFS and RFS), and to understand whether there is some advantage for a runner to use one or the other of the two landing styles. Eight subjects performed two series of runs (FFS and RFS) on a treadmill at an average speed of 2.50, 2.78, 3.06, 3.33, 3.61, 3.89, 4.17 m s-1. Step frequency, oxygen uptake, mechanical work, and its two components, external and internal, were measured. No differences were found for step frequency, mechanical internal work per unit time and oxygen uptake, while external and total mechanical work per unit time were significantly higher, 7-12%, for FFS. The higher external work was the result of an increase of the work performed against both gravitational and inertial forces. As the energy expenditure was the same it has been speculated that a higher storage and release of energy takes place in the elastic structures of the lower leg with FFS. In a different series of experiments on six subjects contact time, time of deceleration and time of acceleration were measured by means of a video camera while running on the treadmill at 2.50, 3.33 and 4.17 m s-1, both FFS and RFS. Time of deceleration is similar for FFS and RFS, but contact time and time of acceleration are shorter, respectively 12 and 25%, for FFS.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical science

CERN Document Server

Bolton, W C

2013-01-01

This book gives comprehensive coverage of mechanical science for HNC/HND students taking mechanical engineering courses, including all topics likely to be covered in both years of such courses, as well as for first year undergraduate courses in mechanical engineering. It features 500 problems with answers and 200 worked examples. The third edition includes a new section on power transmission and an appendix on mathematics to help students with the basic notation of calculus and solution of differential equations.

How music training enhances working memory: a cerebrocerebellar blending mechanism that can lead equally to scientific discovery and therapeutic efficacy in neurological disorders.

Science.gov (United States)

Vandervert, Larry

2015-01-01

Following in the vein of studies that concluded that music training resulted in plastic changes in Einstein's cerebral cortex, controlled research has shown that music training (1) enhances central executive attentional processes in working memory, and (2) has also been shown to be of significant therapeutic value in neurological disorders. Within this framework of music training-induced enhancement of central executive attentional processes, the purpose of this article is to argue that: (1) The foundational basis of the central executive begins in infancy as attentional control during the establishment of working memory, (2) In accordance with Akshoomoff, Courchesne and Townsend's and Leggio and Molinari's cerebellar sequence detection and prediction models, the rigors of volitional control demands of music training can enhance voluntary manipulation of information in thought and movement, (3) The music training-enhanced blending of cerebellar internal models in working memory as can be experienced as intuition in scientific discovery (as Einstein often indicated) or, equally, as moments of therapeutic advancement toward goals in the development of voluntary control in neurological disorders, and (4) The blending of internal models as in (3) thus provides a mechanism by which music training enhances central executive processes in working memory that can lead to scientific discovery and improved therapeutic outcomes in neurological disorders. Within the framework of Leggio and Molinari's cerebellar sequence detection model, it is determined that intuitive steps forward that occur in both scientific discovery and during therapy in those with neurological disorders operate according to the same mechanism of adaptive error-driven blending of cerebellar internal models. It is concluded that the entire framework of the central executive structure of working memory is a product of the cerebrocerebellar system which can, through the learning of internal models

Total Synthesis of Hyperforin.

Science.gov (United States)

Ting, Chi P; Maimone, Thomas J

2015-08-26

A 10-step total synthesis of the polycyclic polyprenylated acylphloroglucinol (PPAP) natural product hyperforin from 2-methylcyclopent-2-en-1-one is reported. This route was enabled by a diketene annulation reaction and an oxidative ring expansion strategy designed to complement the presumed biosynthesis of this complex meroterpene. The described work enables the preparation of a highly substituted bicyclo[3.3.1]nonane-1,3,5-trione motif in only six steps and thus serves as a platform for the construction of easily synthesized, highly diverse PPAPs modifiable at every position.

Can the error detection mechanism benefit from training the working memory? A comparison between dyslexics and controls--an ERP study.

Directory of Open Access Journals (Sweden)

Tzipi Horowitz-Kraus

Full Text Available BACKGROUND: Based on the relationship between working memory and error detection, we investigated the capacity of adult dyslexic readers' working memory to change as a result of training, and the impact of training on the error detection mechanism. METHODOLOGY: 27 dyslexics and 34 controls, all university students, participated in the study. ERP methodology and behavioral measures were employed prior to, immediately after, and 6 months after training. The CogniFit Personal Coach Program, which consists of 24 sessions of direct training of working memory skills, was used. FINDINGS: Both groups of readers gained from the training program but the dyslexic readers gained significantly more. In the dyslexic group, digit span increased from 9.84+/-3.15 to 10.79+/-3.03. Working memory training significantly increased the number of words per minute read correctly by 14.73%. Adult brain activity changed as a result of training, evidenced by an increase in both working memory capacity and the amplitude of the Error-related Negativity (ERN component (24.71%. When ERN amplitudes increased, the percentage of errors on the Sternberg tests decreased. CONCLUSIONS: We suggest that by expanding the working memory capacity, larger units of information are retained in the system, enabling more effective error detection. The crucial functioning of the central-executive as a sub-component of the working memory is also discussed.

Model-based estimation of finite population total in stratified sampling

African Journals Online (AJOL)

The work presented in this paper concerns the estimation of finite population total under model – based framework. Nonparametric regression approach as a method of estimating finite population total is explored. The asymptotic properties of the estimators based on nonparametric regression are also developed under ...

Independent Attention Mechanisms Control the Activation of Tactile and Visual Working Memory Representations.

Science.gov (United States)

Katus, Tobias; Eimer, Martin

2018-05-01

Working memory (WM) is limited in capacity, but it is controversial whether these capacity limitations are domain-general or are generated independently within separate modality-specific memory systems. These alternative accounts were tested in bimodal visual/tactile WM tasks. In Experiment 1, participants memorized the locations of simultaneously presented task-relevant visual and tactile stimuli. Visual and tactile WM load was manipulated independently (one, two, or three items per modality), and one modality was unpredictably tested after each trial. To track the activation of visual and tactile WM representations during the retention interval, the visual contralateral delay activity (CDA) and tactile CDA (tCDA) were measured over visual and somatosensory cortex, respectively. CDA and tCDA amplitudes were selectively affected by WM load in the corresponding (tactile or visual) modality. The CDA parametrically increased when visual load increased from one to two and to three items. The tCDA was enhanced when tactile load increased from one to two items and showed no further enhancement for three tactile items. Critically, these load effects were strictly modality-specific, as substantiated by Bayesian statistics. Increasing tactile load did not affect the visual CDA, and increasing visual load did not modulate the tCDA. Task performance at memory test was also unaffected by WM load in the other (untested) modality. This was confirmed in a second behavioral experiment where tactile and visual loads were either two or four items, unimodal baseline conditions were included, and participants performed a color change detection task in the visual modality. These results show that WM capacity is not limited by a domain-general mechanism that operates across sensory modalities. They suggest instead that WM storage is mediated by distributed modality-specific control mechanisms that are activated independently and in parallel during multisensory WM.

General load function in geo-mechanics: application to underground works

International Nuclear Information System (INIS)

Maiolino, S.

2006-04-01

This work deals both with the behavioral and numerical aspects of the mechanical response of a rock massif to the digging out of a tunnel. The comparison between existing criteria has permitted to stress on some key points, like the dependence of the criterion to the average stress and the extension ratio. A load function, easily identifiable with tests, with regular and convex properties, has been proposed which allows to take into account the shape of the Mohr envelope of the criterion and the extension ratio. Regularized forms of Mohr-Coulomb and Hoek-Brown criteria can thus be achieved. The development of this new criterion has been completed by the proposal of a numerical charts method which greatly speeds up the resolution. For the proposed criterion, the physical problem is equivalent to a purely geometrical problem in polar coordinates in the plan. Numerical charts can thus be built which allow to find immediately the value of plastic deformations and to greatly reduce the processing time. Tunnel calculation methods have been the object of a bibliographic synthesis, specifying the domains and limitations of use of tunnel dimensioning methods used by engineers. The modeling of tunnels excavation has been performed with the stationary algorithm designed for the calculation of systems submitted to mobile loads. This algorithm has been adapted to integrate the new criterion and the numerical charts system. These tools have been validated using a real case study and data supplied by the French national agency of radioactive waste management (ANDRA) in the framework of the MODEX-REP European project (5. Euratom plan). The study of these data has permitted to define a rock wear variable, easily identifiable and allowing to parameterize the damaged rock criterion. (J.S.)

The Effect of Industrial Work Performance Practice and Performance Automotive Electrical Prakti entrepreneurial n Against Interests Automotive Mechanics Class XII Smk Diponegoro Depok Sleman

OpenAIRE

Arif Mustofa; Pairun Roniwijaya

2013-01-01

The purpose of this study was to determine (1) the influence of the industrial working practices achievement entrepreneurial interests, (2) the effect of automotive electrical practice achievement against entrepreneurial interests, and (3) influence of achievement and accomplishment industry work practices automotive electrical practices to entrepreneurial interest Automotive Mechanics XII class students of SMK Diponegoro Depok Sleman school year 2012/2013.  The results showed that the test r...

Frictional granular mechanics: A variational approach

Energy Technology Data Exchange (ETDEWEB)

Holtzman, R.; Silin, D.B.; Patzek, T.W.

2009-10-16

The mechanical properties of a cohesionless granular material are evaluated from grain-scale simulations. Intergranular interactions, including friction and sliding, are modeled by a set of contact rules based on the theories of Hertz, Mindlin, and Deresiewicz. A computer generated, three-dimensional, irregular pack of spherical grains is loaded by incremental displacement of its boundaries. Deformation is described by a sequence of static equilibrium configurations of the pack. A variational approach is employed to find the equilibrium configurations by minimizing the total work against the intergranular loads. Effective elastic moduli are evaluated from the intergranular forces and the deformation of the pack. Good agreement between the computed and measured moduli, achieved with no adjustment of material parameters, establishes the physical soundness of the proposed model.

Advances in Applied Mechanics

OpenAIRE

2013-01-01

Advances in Applied Mechanics draws together recent significant advances in various topics in applied mechanics. Published since 1948, Advances in Applied Mechanics aims to provide authoritative review articles on topics in the mechanical sciences, primarily of interest to scientists and engineers working in the various branches of mechanics, but also of interest to the many who use the results of investigations in mechanics in various application areas, such as aerospace, chemical, civil, en...

[Health effects and psychological stress in pregnant women engaged in work outside the home].

Science.gov (United States)

Anan, Ayumi; Shiiba, Michiyo; Sibata, Eiji; Kawamoto, Rieko

2010-12-01

Modern society demands working conditions in which pregnant women can successfully deliver children and maintain a professional position. The aim of this study is to investigate the effects of work on the health and psychological stress in working women and their newborns. We reviewed twenty-eight publications and found that health problems in working women occur at high rates. However, there is no report investigating the mechanism by which health problems occur, or describing the precise working conditions and symptoms in pregnant women who are engaged in work outside the home. In addition, the literature uses subjective evaluations, including psychological tests, to quantify stress and anxiety, but no biochemical analyses of stress-related substances were conducted. We suggest that a standard index to represent working conditions and job category, as well as an investigation of the workload of house-keeping, is needed to understand the total work effort by pregnant women in modern times. Finally, measurement of stress-related biological markers may be effective in the investigation from various perspectives of occupational stress in pregnant women.

Effect of heat treatment, with and without mechanical work, on the tensile and creep behaviour at 6000C of austenitic stainless steel stabilised with titanium

International Nuclear Information System (INIS)

Padilha, A.F.

1983-01-01

The effect of various heat treatments, with and without mechanical work, on the microstructure and the tensile and creep behaviour at 600 0 C of the titanium stabilised austenitic stainless steel DIN 1.4970, as well as the effects of aging temperature, pre-strain and small boron additions on the creep behaviour of these steels are discussed. The most probable mechanism is suggested. (Author) [pt

Working mechanism of extracorporeal shockwave therapy in non-urological disciplines

Science.gov (United States)

Schaden, Wolfgang

2005-04-01

For 32 years of extracorporeal shockwave lithotripsy (ESWL) only the mechanical strength of shockwaves were of clinical interest. For use in orthopaedics, the absence of dangerous long term effects (malignant degeneration, etc.) is the only important message. The mechanical model tries to explain the effect of shock waves by the provocation of microleasions in the tissue stimulating repairing processes. First doubts on this mechanical model came up when Schaden (2001) could show, that less energy is more efficient in the treatment of non-unions. Due to the basic research of the last years knowledge increased about the microbiological effects. Under the influence of shock waves the change of permeability of cell membranes and the liberation of free radicals was reported. Also the production of nitric oxide (NO) and different growth factors like vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMP), transforming growth factor-beta 1 (TGF-b1), insulin-like growth factor-I (IGF-I) etc. was observed. The biological model tries to explain the effect of shock waves by stimulating the ingrowth of blood vessels and liberation of growth factors. Under the influence of shock waves, biological tissues seem to be able to produce important substances to initiate healing processes.

Mechanized evaluation of neutron cross-sections

International Nuclear Information System (INIS)

Horsley, A.; Parker, J.B.

1967-01-01

The evaluation work to provide accurate and consistent neutron cross-section data for multigroup neutronics calculations is not fully exploiting the available theoretical and experimental results; this has been so particularly since the introduction of on-line data handling techniques enabled experimenters to turn out vast quantities of numbers. This situation can be radically improved only by mechanizing the evaluation processes. Systems such as the SC1SRS tape will not only largely overcome the task of collecting data but will provide speedy access to it; by using computers and graph-plotting machines to tabulate and display this data, the labour of evaluation can be very greatly reduced. With some types of cross-section there is hope that by using modern curve-fitting techniques the actual evaluation and statistical accounting of the data can be performed automatically. Some areas where automatic evaluation would seem likely to succeed are specified and a discussion of the mathematical difficulties incurred, such as the elimination of anomalous data, is given. Particularly promising is the use of splines in the mechanized evaluation of data. Splines are the mathematical analogues of the draughtsman's spline used in drawing smooth curves. Their principal properties are the excellent approximations they give to the derivatives of a function; in contrast to conventional polynomial fitting, this feature ensures good interpolation and, when required, stable extrapolation. Various methods of using splines in data graduation and the problem of marrying these methods to standard statistical procedures are examined. The results of work done at AWRE with cubic splines on the mechanized evaluation of neutron scattering total cross-section and angular distribution data are presented. (author)

Mechanization of hand labour in special protective works

International Nuclear Information System (INIS)

Zhukov, O.A.; Arnol'd, V.V.; Gavritenkov, I.A.; Selyanko, V.G.

1986-01-01

New high-efficient technologies introduced in Souzehnergozashchita unit corporation are described in short. The corporation deals with mounting of setting and thermal insulation as well as with works on corrosion protection of TPP and NPP equipment. The innovations include the introduction of polymeric coatings of floors, epoxide enamels for construction structure protection, polymeric materials for which a flame plating technology has been developed

Determination of diffusible and total hydrogen concentration in coated and uncoated steel

Energy Technology Data Exchange (ETDEWEB)

Mabho, Nonhlangabezo

2010-09-23

The new trend in the steel industry demands thin, flexible, high strength steels with low internal embrittlement. It is a well known fact that the atomic hydrogen which is picked up during production, fabrication and service embrittles the steel. This has led to an extensive research towards the improvement of the quality of metallic materials by focusing on total and diffusible hydrogen concentrations which are responsible for hydrogen embrittlement. Since the internal embrittlement cannot be foreseen, the concentrations of diffusible hydrogen work as indicators while the total hydrogen characterizes the absorbed quantities and quality of that particular product. To meet these requirements, the analytical chemistry methods which include the already existing carrier gas melt (fusion) extraction methods that use infrared and thermal conductivity for total hydrogen detection were applied. The newly constructed carrier gas thermal desorption mass spectroscopy was applied to monitor the diffusible concentration at specific temperatures and desorption rates of hydrogen which will contribute towards the quality of materials during service. The TDMS method also involved the characterization of the energy quantity (activation energy) required by hydrogen to be removed from traps of which irreversible traps are preferred because they enhance the stability of the product by inhibiting the mobility of hydrogen which is detrimental to the metallic structures. The instrumentation for TDMS is quite simple, compact, costs less and applicable to routine analysis. To determine total and diffusible hydrogen, the influence of the following processes: chemical and mechanical zinc coating removal, sample cleaning with organic solvents, conditions for hydrogen absorption by electrolytic hydrogen charging, conditions of hydrogen desorption by storing the sample at room temperature, solid CO{sub 2} and at temperatures of the drier was analysed. The contribution of steel alloys towards

Daily sleep, weekly working hours, and risk of work-related injury: US National Health Interview Survey (2004-2008).

Science.gov (United States)

Lombardi, David A; Folkard, Simon; Willetts, Joanna L; Smith, Gordon S

2010-07-01

The impact on health and safety of the combination of chronic sleep deficits and extended working hours has received worldwide attention. Using the National Health Interview Survey (NHIS), an in-person household survey using a multistage, stratified, clustered sample design representing the US civilian, non-institutionalized population, the authors estimated the effect of total daily self-reported sleep time and weekly working hours on the risk of a work-related injury. During the survey period 2004-2008, 177,576 persons (ages 18-74) sampled within households reported that they worked at a paid job the previous week and reported their total weekly work hours. A randomly selected adult in each household (n = 75,718) was asked to report his/her usual (average) total daily sleep hours the prior week; complete responses were obtained for 74,415 (98.3%) workers. Weighted annualized work-related injury rates were then estimated across a priori defined categories of both average total daily sleep hours and weekly working hours. To account for the complex sampling design, weighted multiple logistic regression was used to independently estimate the risk of a work-related injury for categories of usual daily sleep duration and weekly working hours, controlling for important covariates and potential confounders of age, sex, race/ethnicity, education, type of pay, industry, occupation (proxy for job risk), body mass index, and the interaction between sleep duration and work hours. Based on the inclusion criteria, there were an estimated 129,950,376 workers annually at risk and 3,634,446 work-related medically treated injury episodes (overall injury rate 2.80/100 workers). Unadjusted annualized injury rates/100 workers across weekly work hours were 2.03 (60 h). With regards to self-reported daily sleep time, the estimated annualized injury rates/100 workers were 7.89 (10 h). After controlling for weekly work hours, and aforementioned covariates, significant increases in risk/1

Adapting Total Quality Management (TQM) to Government.

Science.gov (United States)

Swiss, James E.

1992-01-01

Total quality management will not work well in government agencies because of stress on products, not services; on well-defined consumer groups; on inputs/processes, not results; and on preoccupation with quality. An effective revised version emphasizes client feedback, performance monitoring, continuous improvement, and worker participation. (SK)

Total working period and other risk factors related to eating protein foods habits among civil pilots in Indonesia

Directory of Open Access Journals (Sweden)

Indah Imelda Hutabarat

2017-07-01

pilots in Indonesia. Methods: A cross-sectional study using secondary data from the survey of eating, drinking and physical exercise habits among civilian pilots in Indonesia 2016. Data collected were demographic characteristics, physical exercise habits, smoking habits, knowledge, body mass index and flight characteristics. Cox regression analysis was used to analyze the dominant factors associated with protein eating habits. Results: Among 528 pilots aged 19-64 years, 194 (36.74% pilots had excessive protein eating habits . Long working period and body mass index were the dominant risk factors associated with protein eating habit in pilots. Compared to pilots with 1-9 years working period, pilots with 10-40 years working period had 35% lower risk of excessive protein eating habits (RRA = 0.65; 95% CI 0:49 - 0.87. Compared to pilots with normal body mass index, overweight pilots had 34% lower risk of excessive protein eating habits (RRA = 0.66; 95% CI 0:47 - 0.93. Conclusion: Long working period and overweight were protective factors from the risk of excessive protein eating habits Keywords: protein eating habits, total working periode, body mass index, civilian pilots Indonesia

Mechanization of refractory relining and disintegration work for ladle and RH-degassing vessel; Toribe, RH datsu gas ro ni okeru seko oyobi kaitai sagyo no kikaika

Energy Technology Data Exchange (ETDEWEB)

Kuwayama, M; Yoshida, M [Kawasaki Steel Corp., Tokyo (Japan); Yamaguchi, T [Kawasaki Refractories Corp. Ltd., Hyogo (Japan)

1996-02-01

In iron and steel industry, automation and mechanization of furnace relining work are required as the measures of the environmental betterment therein which is extremely important for ensuring the factors in the future. In this paper, the inductions of the equipment for castable refractory relining at the bottom of the ladle, the equipment for handling slag line bricks of the ladle, the equipment for brick disintegration in the RH-degassing vessel which have been mechanized recently at the Mizushiminduction`s Kawasaki Steel Corporation as a part of the betterment of furnace relining work carried out hitherto are described. The main points of said betterment are indicated hereafter. The equipment for castable refractory relining at the bottom of the ladle is exploited and utilized. The hard works are lightened by the large scale of the bricks for the slag line of the ladle and the induction of the vacuum lifter. The equipment exclusive for disintegration in the RH-degassing vessel is exploited and utilized. Owing to the above-mentioned improvements, 27% and 60% of the operation time are reduced in the relining work for the ladle and disintegration work for the RH-degassing vessel respectively. 9 figs., 2 tabs.

Shift work and cardiovascular disease - pathways from circadian stress to morbidity.

Science.gov (United States)

Puttonen, Sampsa; Härmä, Mikko; Hublin, Christer

2010-03-01

In order to establish a causal relation between shift work and cardiovascular disease (CVD), we need to verify the pathways from the former to the latter. This paper aims to review the current knowledge of the mechanisms between shift work and CVD. Shift work can increase the risk of CVD by several interrelated psychosocial, behavioral, and physiological mechanisms. The psychosocial mechanisms relate to difficulties in controlling working hours, decreased work-life balance, and poor recovery following work. The most probable behavioral changes are weight gain and smoking. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changed lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The data provide evidence for possible disease mechanisms between shift work and CVD, but compelling evidence on any specific mechanism is missing.

Automatization and mechanization of welding in nuclear engineering

Energy Technology Data Exchange (ETDEWEB)

Shul' ma, I E; Kupin, N V

1986-02-01

The state of welding and cladding works, which constitute more than 12% of total labour content of NPP equipment production, is described. Special attention is paid to a considerable part of manual labour in the processes of thermal cutting and welding of joints inside the vessels. The necessity of perspective technology introduction is pointed out. It means, in particular, the introduction of technological complex robotics for automatic welding of pipes with tube plates in heat exchanger, the mechanization of cladding processes for sealing surfaces of locking equipment, facility equipment for the welding of steam generator vessels to bottoms by means of preliminary and concomitant heating devices.

Automatization and mechanization of welding in nuclear engineering

International Nuclear Information System (INIS)

Shul'ma, I.E.; Kupin, N.V.

1986-01-01

The state of welding and cladding works, which constitute more than 12% of total labour content of NPP equipment production, is described. Special attention is paid to a considerable part of manual labour in the processes of thermal cutting and welding of joints inside the vessels. The necessity of perspective technology introduction is pointed out. It means, in particular, the introduction of technological complex robotics for automatic welding of pipes with tube plates in heat exchanger, the mechanization of cladding processes for sealing surfaces of locking equipment, facility equipment for the welding of steam generator vessels to bottoms by means of preliminary and concomitant heating devices

Supercritical Water Oxidation Total Organic Carbon (TOC) Analysis

Science.gov (United States)

The work presented here is the evaluation of the modified wet‐oxidation method described as Supercritical Water Oxidation (SCWO) for the analysis of total organic carbon (TOC) in very difficult oil/gas produced water sample matrices.

HFCVD Diamond-Coated Mechanical Seals

Directory of Open Access Journals (Sweden)

Raul Simões

2018-05-01

Full Text Available A mechanical seal promotes the connection between systems or mechanisms, preventing the escape of fluids to the exterior. Nonetheless, due to extreme working conditions, premature failure can occur. Diamond, due to its excellent properties, is heralded as an excellent choice to cover the surface of these devices and extend their lifetime. Therefore, the main objective of this work was to deposit diamond films over mechanical seals and test the coated seals on a water pump, under real working conditions. The coatings were created by hot filament chemical vapor deposition (HFCVD and two consecutive layers of micro- and nanocrystalline diamond were deposited. One of the main difficulties is the attainment of a good adhesion between the diamond films and the mechanical seal material (WC-Co. Nucleation, deposition conditions, and pre-treatments were studied to enhance the coating. Superficial wear or delamination of the film was investigated using SEM and Raman characterization techniques, in order to draw conclusions about the feasibility of these coatings in the WC-Co mechanical seals with the purpose of increasing their performance and life time. The results obtained gave a good indication about the feasibility of this process and the deposition conditions used, with the mechanical seals showing no wear and no film delamination after a real work environment test.

Lower extremity work is associated with club head velocity during the golf swing in experienced golfers.

Science.gov (United States)

McNally, M P; Yontz, N; Chaudhari, A M

2014-08-01

While the golf swing is a complex whole body movement requiring coordination of all joints to achieve maximum ball velocity, the kinetic contribution of the lower extremities to club head velocity has not been quantified, despite the perception that the legs are a primary source of power during the swing. Mechanical power at the hips, knees, and ankles was estimated during the downswing phase of a full swing with a driver using a passive optical motion capture system and 2 force plates for adult males across a range of age and self-reported skill levels. Total work by the lower extremities was calculated by integrating the powers of all 6 joints over the downswing. Regression analyses showed that total lower extremity work was a strong predictor of club head velocity (R=0.63). Secondary analyses showed different relationships to club head velocity in lead and trail leg lower extremity joints, but none of these were as predictive of club head velocity as the total work performed by the lower extremities. These results provide quantitative evidence that the lower body's kinetic contribution may be an important factor in achieving greater club head velocity, contributing to greater driving distance and overall golf performance. © Georg Thieme Verlag KG Stuttgart · New York.

Work stress, poor recovery and burnout in teachers.

Science.gov (United States)

Gluschkoff, K; Elovainio, M; Kinnunen, U; Mullola, S; Hintsanen, M; Keltikangas-Järvinen, L; Hintsa, T

2016-10-01

Both work stress and poor recovery have been shown to contribute to the development of burnout. However, the role of recovery as a mediating mechanism that links work stress to burnout has not been sufficiently addressed in research. To examine recovery as a mediator in the relationship between work stress and burnout among teachers. A cross-sectional study of Finnish primary school teachers, in whom burnout was measured with the Maslach Burnout Inventory-General Survey and work stress was conceptualized using the effort-reward imbalance (ERI) model. Recovery was measured with the Recovery Experience Questionnaire and the Jenkins Sleep Problems Scale. Multiple linear regression analyses and bootstrap mediation analyses adjusted for age, gender and total working hours were performed. Among the 76 study subjects, high ERI was associated with burnout and its dimensions of exhaustion, cynicism and reduced professional efficacy. Poor recovery experiences, in terms of low relaxation during leisure time, partially mediated the relationship between ERI and reduced professional efficacy. Sleep problems, in the form of non-restorative sleep, partially mediated the relationship between ERI and both burnout and exhaustion. Supporting a balance between effort and reward at work may enhance leisure time recovery and improve sleep quality, as well as help to reduce burnout rates. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Total Humeral Endoprosthetic Replacement following Excision of Malignant Bone Tumors

Directory of Open Access Journals (Sweden)

Suhel Kotwal

2016-01-01

Full Text Available Humerus is a common site for malignant tumors. Advances in adjuvant therapies and reconstructive methods provide salvage of the upper limb with improved outcomes. Reports of limb salvage with total humeral replacement in extensive humeral tumors are sparse. We undertook a retrospective study of 20 patients who underwent total humeral endoprosthetic replacement as limb salvage following excision of extensile malignant tumor from 1990 to 2011. With an average followup of 42.9, functional and oncological outcomes were analyzed. Ten patients were still alive at the time of review. Mean estimated blood loss was 1131 mL and duration of surgery was 314 minutes. Deep infection was encountered in one patient requiring debridement while mechanical loosening of ulnar component was identified in one patient. Subluxation of prosthetic humeral head was noted in 3 patients. Mean active shoulder abduction was 12.5° and active flexion was 15°. Incompetence of abduction mechanism was the major determinant of poor active functional outcome. Mean elbow flexion was 103.5° with 30.5° flexion contracture in 10 patients with good and useful hand function. Average MSTS score was 71.5%. Total humeral replacement is a reliable treatment option in restoring mechanical stability and reasonable functional results without compromising patient survival, with low complication rate.

Mechanical Design of High Lift Systems for High Aspect Ratio Swept Wings

Science.gov (United States)

Rudolph, Peter K. C.

1998-01-01

The NASA Ames Research Center is working to develop a methodology for the optimization and design of the high lift system for future subsonic airliners with the involvement of two partners. Aerodynamic analysis methods for two dimensional and three dimensional wing performance with flaps and slats deployed are being developed through a grant with the aeronautical department of the University of California Davis, and a flap and slat mechanism design procedure is being developed through a contract with PKCR, Inc., of Seattle, WA. This report documents the work that has been completed in the contract with PKCR on mechanism design. Flap mechanism designs have been completed for seven (7) different mechanisms with a total of twelve (12) different layouts all for a common single slotted flap configuration. The seven mechanisms are as follows: Simple Hinge, Upside Down/Upright Four Bar Linkage (two layouts), Upside Down Four Bar Linkages (three versions), Airbus A330/340 Link/Track Mechanism, Airbus A320 Link/Track Mechanism (two layouts), Boeing Link/Track Mechanism (two layouts), and Boeing 767 Hinged Beam Four Bar Linkage. In addition, a single layout has been made to investigate the growth potential from a single slotted flap to a vane/main double slotted flap using the Boeing Link/Track Mechanism. All layouts show Fowler motion and gap progression of the flap from stowed to a fully deployed position, and evaluations based on spanwise continuity, fairing size and number, complexity, reliability and maintainability and weight as well as Fowler motion and gap progression are presented. For slat design, the options have been limited to mechanisms for a shallow leading edge slat. Three (3) different layouts are presented for maximum slat angles of 20 deg, 15 deg and 1O deg all mechanized with a rack and pinion drive similar to that on the Boeing 757 airplane. Based on the work of Ljungstroem in Sweden, this type of slat design appears to shift the lift curve so that

Collaborative problem solving with a total quality model.

Science.gov (United States)

Volden, C M; Monnig, R

1993-01-01

A collaborative problem-solving system committed to the interests of those involved complies with the teachings of the total quality management movement in health care. Deming espoused that any quality system must become an integral part of routine activities. A process that is used consistently in dealing with problems, issues, or conflicts provides a mechanism for accomplishing total quality improvement. The collaborative problem-solving process described here results in quality decision-making. This model incorporates Ishikawa's cause-and-effect (fishbone) diagram, Moore's key causes of conflict, and the steps of the University of North Dakota Conflict Resolution Center's collaborative problem solving model.

Working memory delay period activity marks a domain-unspecific attention mechanism.

Science.gov (United States)

Katus, Tobias; Müller, Matthias M

2016-03-01

Working memory (WM) recruits neural circuits that also perform perception- and action-related functions. Among the functions that are shared between the domains of WM and perception is selective attention, which supports the maintenance of task-relevant information during the retention delay of WM tasks. The tactile contralateral delay activity (tCDA) component of the event-related potential (ERP) marks the attention-based rehearsal of tactile information in somatosensory brain regions. We tested whether the tCDA reflects the competition for shared attention resources between a WM task and a perceptual task under dual-task conditions. The two tasks were always performed on opposite hands. In different blocks, the WM task had higher or lower priority than the perceptual task. The tCDA's polarity consistently reflected the hand where the currently prioritized task was performed. This suggests that the process indexed by the tCDA is not specific to the domain of WM, but mediated by a domain-unspecific attention mechanism. The analysis of transient ERP components evoked by stimuli in the two tasks further supports the interpretation that the tCDA marks a goal-directed bias in the allocation of selective attention. Larger spatially selective modulations were obtained for stimulus material related to the high-, as compared to low-priority, task. While our results generally indicate functional overlap between the domains of WM and perception, we also found evidence suggesting that selection in internal (mnemonic) and external (perceptual) stimulus representations involves processes that are not active during shifts of preparatory attention. Copyright © 2016 Elsevier Inc. All rights reserved.

Mechanical energy profiles of the combined ankle-foot system in normal gait: insights for prosthetic designs.

Science.gov (United States)

Takahashi, Kota Z; Stanhope, Steven J

2013-09-01

Over the last half-century, the field of prosthetic engineering has continuously evolved with much attention being dedicated to restoring the mechanical energy properties of ankle joint musculatures during gait. However, the contributions of 'distal foot structures' (e.g., foot muscles, plantar soft tissue) have been overlooked. Therefore, the purpose of this study was to quantify the total mechanical energy profiles (e.g., power, work, and work-ratio) of the natural ankle-foot system (NAFS) by combining the contributions of the ankle joint and all distal foot structures during stance in level-ground steady state walking across various speeds (0.4, 0.6, 0.8 and 1.0 statures/s). The results from eleven healthy subjects walking barefoot indicated ankle joint and distal foot structures generally performed opposing roles: the ankle joint performed net positive work that systematically increased its energy generation with faster walking speeds, while the distal foot performed net negative work that systematically increased its energy absorption with faster walking speeds. Accounting for these simultaneous effects, the combined ankle-foot system exhibited increased work-ratios with faster walking. Most notably, the work-ratio was not significantly greater than 1.0 during the normal walking speed of 0.8 statures/s. Therefore, a prosthetic design that strategically exploits passive-dynamic properties (e.g., elastic energy storage and return) has the potential to replicate the mechanical energy profiles of the NAFS during level-ground steady-state walking. Copyright © 2013 Elsevier B.V. All rights reserved.

Quantum mechanical aspects of dynamical neutron polarization

International Nuclear Information System (INIS)

Betz, T.; Badurek, G.; Jericha, E.

2007-01-01

Dynamic Neutron Polarization (DNP) is a concept which allows to achieve complete polarization of slow neutrons, virtually without any loss of intensity. There the neutrons pass through a combination of a static and a rotating magnetic field in resonance, like in a standard NMR apparatus. Depending on their initial spin state, they end up with different kinetic energies and therefore different velocity. In a succeeding magnetic precession field this distinction causes a different total precession angle. Tuning the field strength can lead to a final state where two original anti-parallel spin states are aligned parallel and hence to polarization. The goal of this work is to describe the quantum mechanical aspects of DNP and to work out the differences to the semi-classical treatment. We show by quantum mechanical means, that the concept works and DNP is feasible, indeed. Therefore, we have to take a closer look to the behavior of neutron wave functions in magnetic fields. In the first Section we consider a monochromatic continuous beam. The more realistic case of a pulsed, polychromatic beam requires a time-dependent field configuration and will be treated in the second Section. In particular the spatial separation of the spin up- and down-states is considered, because it causes an effect of polarization damping so that one cannot achieve a fully polarized final state. This effect is not predicted by the semi-classical treatment of DNP. However, this reduction of polarization is very small and can be neglected in realistic DNP-setups

Rehabilitation after total joint replacement: a scoping study.

Science.gov (United States)

L Snell, Deborah; Hipango, Julia; Sinnott, K Anne; Dunn, Jennifer A; Rothwell, Alastair; Hsieh, C Jean; DeJong, Gerben; Hooper, Gary

2018-07-01

The evidence supporting rehabilitation after joint replacement, while vast, is of variable quality making it difficult for clinicians to apply the best evidence to their practice. We aimed to map key issues for rehabilitation following joint replacement, highlighting potential avenues for new research. We conducted a scoping study including research published between January 2013 and December 2016, evaluating effectiveness of rehabilitation following hip and knee total joint replacement. We reviewed this work in the context of outcomes described from previously published research. Thirty individual studies and seven systematic reviews were included, with most research examining the effectiveness of physiotherapy-based exercise rehabilitation after total knee replacement using randomized control trial methods. Rehabilitation after hip and knee replacement whether carried out at the clinic or monitored at home, appears beneficial but type, intensity and duration of interventions were not consistently associated with outcomes. The burden of comorbidities rather than specific rehabilitation approach may better predict rehabilitation outcome. Monitoring of recovery and therapeutic attention appear important but little is known about optimal levels and methods required to maximize outcomes. More work exploring the role of comorbidities and key components of therapeutic attention and the therapy relationship, using a wider range of study methods may help to advance the field. Implications for Rehabilitation Physiotherapy-based exercise rehabilitation after total hip replacement and total knee replacement, whether carried out at the clinic or monitored at home, appears beneficial. Type, intensity, and duration of interventions do not appear consistently associated with outcomes. Monitoring a patient's recovery appears to be an important component. The available research provides limited guidance regarding optimal levels of monitoring needed to achieve gains following hip

Work-Related Basic Need Satisfaction as a Predictor of Work Engagement among Academic Staff in Turkey

Science.gov (United States)

Silman, Fatos

2014-01-01

This study examines the relationship between work-related basic need satisfaction and work engagement. Data were obtained from a total of 203 academics who are employed in various universities of Turkey. In this research Work-Related Basic Need Satisfaction Scale and The Turkish Form of Utrecht Work Engagement Scale were utilized. The data were…

Mechanics and Physics of Precise Vacuum Mechanisms

CERN Document Server

Deulin, E. A; Panfilov, Yu V; Nevshupa, R. A

2010-01-01

In this book the Russian expertise in the field of the design of precise vacuum mechanics is summarized. A wide range of physical applications of mechanism design in electronic, optical-electronic, chemical, and aerospace industries is presented in a comprehensible way. Topics treated include the method of microparticles flow regulation and its determination in vacuum equipment and mechanisms of electronics; precise mechanisms of nanoscale precision based on magnetic and electric rheology; precise harmonic rotary and not-coaxial nut-screw linear motion vacuum feedthroughs with technical parameters considered the best in the world; elastically deformed vacuum motion feedthroughs without friction couples usage; the computer system of vacuum mechanisms failure predicting. This English edition incorporates a number of features which should improve its usefulness as a textbook without changing the basic organization or the general philosophy of presentation of the subject matter of the original Russian work. Exper...

Breaststroke swimmers moderate internal work increases toward the highest stroke frequencies.

Science.gov (United States)

Lauer, Jessy; Olstad, Bjørn Harald; Minetti, Alberto Enrico; Kjendlie, Per-Ludvik; Rouard, Annie Hélène

2015-09-18

A model to predict the mechanical internal work of breaststroke swimming was designed. It allowed us to explore the frequency-internal work relationship in aquatic locomotion. Its accuracy was checked against internal work values calculated from kinematic sequences of eight participants swimming at three different self-chosen paces. Model predictions closely matched experimental data (0.58 ± 0.07 vs 0.59 ± 0.05 J kg(-1)m(-1); t(23)=-0.30, P=0.77), which was reflected in a slope of the major axis regression between measured and predicted total internal work whose 95% confidence intervals included the value of 1 (β=0.84, [0.61, 1.07], N=24). The model shed light on swimmers ability to moderate the increase in internal work at high stroke frequencies. This strategy of energy minimization has never been observed before in humans, but is present in quadrupedal and octopedal animal locomotion. This was achieved through a reduced angular excursion of the heaviest segments (7.2 ± 2.9° and 3.6 ± 1.5° for the thighs and trunk, respectively, Paquatic movements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pulsed total dose damage effect experimental study on EPROM

International Nuclear Information System (INIS)

Luo Yinhong; Yao Zhibin; Zhang Fengqi; Guo Hongxia; Zhang Keying; Wang Yuanming; He Baoping

2011-01-01

Nowadays, memory radiation effect study mainly focus on functionality measurement. Measurable parameters is few in china. According to the present situation, threshold voltage testing method was presented on floating gate EPROM memory. Experimental study of pulsed total dose effect on EPROM threshold voltage was carried out. Damage mechanism was analysed The experiment results showed that memory cell threshold voltage negative shift was caused by pulsed total dose, memory cell threshold voltage shift is basically coincident under steady bias supply and no bias supply. (authors)

Microstructure and Mechanical Properties of Porous Mullite

Science.gov (United States)

Hsiung, Chwan-Hai Harold

Mullite (3 Al2O3 : 2 SiO2) is a technologically important ceramic due to its thermal stability, corrosion resistance, and mechanical robustness. One variant, porous acicular mullite (ACM), has a unique needle-like microstructure and is the material platform for The Dow Chemical Company's diesel particulate filter AERIFY(TM). The investigation described herein focuses on the microstructure-mechanical property relationships in acicular mullites as well as those with traditional porous microstructures with the goal of illuminating the critical factors in determining their modulus, strength, and toughness. Mullites with traditional pore morphologies were made to serve as references via slipcasting of a kaolinite-alumina-starch slurry. The starch was burned out to leave behind a pore network, and the calcined body was then reaction-sintered at 1600C to form mullite. The samples had porosities of approximately 60%. Pore size and shape were altered by using different starch templates, and pore size was found to influence the stiffness and toughness. The ACM microstructure was varied along three parameters: total porosity, pore size, and needle size. Total porosity was found to dominate the mechanical behavior of ACM, while increases in needle and pore size increased the toughness at lower porosities. ACM was found to have much improved (˜130%) mechanical properties relative to its non-acicular counterpart at the same porosity. A second set of investigations studied the role of the intergranular glassy phase which wets the needle intersections of ACM. Removal of the glassy phase via an HF etch reduced the mechanical properties by ˜30%, highlighting the intergranular phase's importance to the enhanced mechanical properties of ACM. The composition of the glassy phase was altered by doping the ACM precursor with magnesium and neodymium. Magnesium doping resulted in ACM with greatly reduced fracture strength and toughness. Studies showed that the mechanical properties of the

Experimental determination of the effects of annealing on the micro-structures and mechanical properties of cold-worked alpha-brass

Science.gov (United States)

Edward, Aghogho Bright; Izelu, Christopher

2013-12-01

Experimental determination of the effect of annealing on the microstructure and mechanical properties of a cold work 70 - 30 brass, was carried out by subjecting specimens of the material to various degrees of cold-work (20%, 40% and 60%), by straining using a tensile machine. The specimens for each degree of cold work were then annealed at 250°C, 350°C, 450°C and 600°C, for 30 minutes. The approach involves the use of metallographic techniques: grinding, polishing and etching to reveal the microstructure while tensile test was carried out on the specimen using a Monsanto tensometer so as to obtain the load/extension graph from which the tensile strength and hardness values were obtained. From the results obtained, it was conclusive that annealing produced finer grains and eliminates prior cold work whereby the material becomes ductile. However, there should be an appreciable deformation for this effect to be noticed. One important aspect of re-crystallization in structural materials is that there is a loss of strength which accompanies disappearance of the cold-worked grains when subjected to high temperature applications. Yet, it is often difficult to establish the exact range of permissible temperature. This work establishes a range for the re-crystallization of alpha brass as 350°C < TC < 450°C, where TC is the re-crystallization temperature. Thus, it will be safe to apply this material at temperatures below 350°C, without fear of structural changes with accompanying lost in strength.

Math anxiety and math performance in children: The mediating roles of working memory and math self-concept.

Science.gov (United States)

Justicia-Galiano, M José; Martín-Puga, M Eva; Linares, Rocío; Pelegrina, Santiago

2017-12-01

Numerous studies, most of them involving adolescents and adults, have evidenced a moderate negative relationship between math anxiety and math performance. There are, however, a limited number of studies that have addressed the mechanisms underlying this relation. This study aimed to investigate the role of two possible mediational mechanisms between math anxiety and math performance. Specifically, we sought to test the simultaneous mediating role of working memory and math self-concept. A total of 167 children aged 8-12 years participated in this study. Children completed a set of questionnaires used to assess math and trait anxiety, math self-concept as well as measures of math fluency and math problem-solving. Teachers were asked to rate each student's math achievement. As measures of working memory, two backward span tasks were administered to the children. A series of multiple mediation analyses were conducted. Results indicated that both mediators (working memory and math self-concept) contributed to explaining the relationship between math anxiety and math achievement. Results suggest that working memory and self-concept could be worth considering when designing interventions aimed at helping students with math anxiety. Longitudinal designs could also be used to better understand the mediational mechanisms that may explain the relationship between math anxiety and math performance. © 2017 The British Psychological Society.

[Work, momentum and fatigue in the work of Daniel Bernoulli: toward the optimization of biological fact].

Science.gov (United States)

Fonteneau, Yannick; Viard, Jérôme

The concept of mechanical work is inherited from the concepts of potentia absoluta and men's work, both implemented in the section IX of Daniel Bernoulli's Hydrodynamica in 1738. Nonetheless, Bernoulli did not confuse these two entities: he defined a link from gender to species between the former, which is general, and the latter, which is organic. In addition, Bernoulli clearly distinguished between vis viva and potentia absoluta (or work). Their reciprocal conversions are rarely mentioned explicitly in this book, except once, in the section X of his work, from vis viva to work, and subordinated to the mediation of a machine, in a driving forces substitution problem. His attitude evolved significantly in a text in 1753, in which work and vis viva were unambiguously connected, while the concept of potentia absoluta was reduced to that of human work, and the expression itself was abandoned. It was then accepted that work can be converted into vis viva, but the opposite is true in only one case, the intra-organic one. It is the concept of fatigue, seen as an expenditure of animal spirits themselves conceived of as little tensed springs releasing vis viva, that allowed the conversion, never quantified and listed simply as a model, from vis viva to work. Thus, work may have ultimately appeared as a transitional state between two kinds of vis viva, of which the first is non-quantifiable. At the same time, the natural elements were discredited from any hint of profitable production. Only men and animals were able to work in the strict sense of the word. Nature, left to itself, does not work, according to Bernoulli. In spite of his wish to bring together rational mechanics and practical mechanics, one perceived in the work of Bernoulli the subsistence of a rarely crossed disjunction between practical and theoretical fields.

Long hours in paid and domestic work and subsequent sickness absence: does control over daily working hours matter?

Science.gov (United States)

Ala-Mursula, L; Vahtera, J; Kouvonen, A; Väänänen, A; Linna, A; Pentti, J; Kivimäki, M

2006-09-01

To explore the associations of working hours (paid, domestic, commuting, and total) with sickness absence, and to examine whether these associations vary according to the level of employee control over daily working hours. Prospective cohort study among 25 703 full-time public sector employees in 10 towns in Finland. A survey of working hours and control over working hours was carried out in 2000-01. The survey responses were linked with register data on the number of self-certified (3 days) sickness absences until the end of 2003. Poisson regression analyses with generalised estimating equations were used to take into account the fact that the employees were nested within work units. Adjustments were made for work and family characteristics and health behaviour. The mean follow-up period was 28.1 (SD 8.1) months. Long domestic and total working hours were associated with higher rates of medically certified sickness absences among both genders. In contrast, long paid working hours were associated with lower rates of subsequent self-certified sickness absences. Long commuting hours were related to increased rates of sickness absence of both types. Low control over daily working hours predicted medically certified sickness absences for both the women and men and self-certified absences for the men. In combinations, high control over working hours reduced the adverse associations of long domestic and total working hours with medically certified absences. Employee control over daily working hours may protect health and help workers successfully combine a full-time job with the demands of domestic work.

Mechanics of Failure Mechanisms in Structures

CERN Document Server

Carlson, R L; Craig, J I

2012-01-01

This book focuses on the mechanisms and underlying mechanics of failure in various classes of materials such as metallic, ceramic, polymeric, composite and bio-material.  Topics include tensile and compressive fracture, crack initiation and growth, fatigue and creep rupture in metallic materials, matrix cracking and delamination and environmental degradation in polymeric composites, failure of bio-materials such as prosthetic heart valves and prosthetic hip joints, failure of ceramics and ceramic matrix composites, failure of metallic matrix composites, static and dynamic buckling failure, dynamic excitations and creep buckling failure in structural systems. Chapters are devoted to failure mechanisms that are characteristic of each of the materials.  The work also provides the basic elements of fracture mechanics and studies in detail several niche topics such as the effects of toughness gradients, variable amplitude loading effects in fatigue, small fatigue cracks, and creep induced brittleness. Furthe...

Changing work, changing health: can real work-time flexibility promote health behaviors and well-being?

Science.gov (United States)

Moen, Phyllis; Kelly, Erin L; Tranby, Eric; Huang, Qinlei

2011-12-01

This article investigates a change in the structuring of work time, using a natural experiment to test whether participation in a corporate initiative (Results Only Work Environment; ROWE) predicts corresponding changes in health-related outcomes. Drawing on job strain and stress process models, we theorize greater schedule control and reduced work-family conflict as key mechanisms linking this initiative with health outcomes. Longitudinal survey data from 659 employees at a corporate headquarters shows that ROWE predicts changes in health-related behaviors, including almost an extra hour of sleep on work nights. Increasing employees' schedule control and reducing their work-family conflict are key mechanisms linking the ROWE innovation with changes in employees' health behaviors; they also predict changes in well-being measures, providing indirect links between ROWE and well-being. This study demonstrates that organizational changes in the structuring of time can promote employee wellness, particularly in terms of prevention behaviors.

A CTAB Procedure Of Total Genomic DNA Extraction For Medicinal Mushrooms

International Nuclear Information System (INIS)

Azhar Mohamad; Muhammad Hussaini Mohd Mustafa; Muhammad Hanif Azhari Noor; Rosnani Abdul Rashid; Hasan Hamdani Hasan Mutaat; Meswan Meskom; Mat Rasol Awang

2014-01-01

Medicinal mushroom is defined as mushrooms used in medicine or medical research. Isolation of intact, high-molecular-mass genomic DNA is essential for many molecular biology applications including Polymerase Chain Reaction (PCR), endonuclease restriction digestion, Southern blot analysis, and genomic library construction. The most important and prerequisite towards reliable molecular biology work is the total genomic DNA of a sample must be in good quality. Five freshly samples of medicinal mushroom were used in this work known as Auriculariapolytricha, Lentinus edode, Pleurotus sayorcaju, Sczhizopyllum commune and Ganodermalucidum. 5 mg of each sample were used to extraction the DNA, prepared in 3 replications and repeated twice. PCR based technique by using ISSR markers were used in checking the amplification ability of the total genomic extraction. A standard Doyle and Doyle protocol for genomic DNA extraction was modified in optimizing the total genomic DNA from the medicinal mushroom.The modification parameters were percentage of CTAB, incubation period and temperature. The results reveal that each sample required a certain combinations of time and period of incubation. Besides, percentage of CTAB in the buffer was found significant in giving a high yielding of extracted total genomic DNA. The extracted total genomic DNA from the medicinal mushroom yielded from 39.7 ng/ μl to 919.1 ng/ μl. The different yield among the samples found to be corresponded to polysaccharide content in the medicinal mushrooms. The objective of this works is to optimize total genomic DNA extraction of medicinal mushrooms towards a high quality intact genomic DNA for molecular activities. (author)

Investigation of the Relationship between Work Ability and Work-related Quality of Life in Nurses.

Science.gov (United States)

Abbasi, Milad; Zakerian, Abolfazl; Akbarzade, Arash; Dinarvand, Nader; Ghaljahi, Maryam; Poursadeghiyan, Mohsen; Ebrahimi, Mohammad Hossein

2017-10-01

Work ability of nurses is an index of their job satisfaction and is a crucial factor in job quality and security. This study aimed to investigate the association between work ability and quality of working life and to determine the effective demographic and background variables, among nurses. The present study was conducted among nurses, working in educational hospitals under the supervision of Tehran University of Medical Sciences in 2014. Work Ability Index (WAI) and Work-related Quality of Life (WRQoL) were used. The mean WAI was significantly associated with total WRQoL score and the two of its sub-items including Stress at Work, and General Well-Being ( P -value=0.001). Moreover, the results showed a significant correlation between total WRQoL and WAI Subscales including mental resources ( P -value=0.001), number of current diseases ( P- value=0.02), and work ability in relation to the job demands ( P -value=0.04). The WRQoL and WAI showed significant associations with age and job experience ( P -value=0.001). The average score of WAI and WRQoL was statistically different among various working units ( P -value=0.001). Overall, results support the association between nurses work ability and WRQoL. Monitoring the WRQoL and work ability of employees would help organizations to know their status and take measures to ameliorate the working conditions.

Understanding the Effect of Ni on Mechanical and Wear Properties of Low-Carbon Steel from a View-Point of Electron Work Function

Science.gov (United States)

Lu, Hao; Huang, Xiaochen; Hou, Runfang; Li, D. Y.

2018-04-01

Electron work function (EWF) is correlated to intrinsic properties of metallic materials and can be an alternative parameter to obtain supplementary clues for guiding material design and modification. A higher EWF corresponds to a more stable electronic state, leading to higher resistance to any attempt to change the material structure and properties. In this study, effects of Ni as a solute with a higher EWF on mechanical, electrochemical, and tribological properties of low-carbon steel were investigated. Added Ni, which has more valence electrons, enhanced the electrons-nuclei interaction in the steel, corresponding to higher EWF. As a result, the Ni-added steel showed increased mechanical strength and corrosion resistance, resulting in higher resistances to wear and corrosive wear. Mechanism for the improvements is elucidated through analyzing EWF-related variations in Young's modulus, hardness, corrosion potential, and tribological behavior.

Outgas analysis of mechanical cryocoolers for long lifetime

Science.gov (United States)

Sato, Yoichi; Shinozaki, Keisuke; Sawada, Kenichiro; Sugita, Hiroyuki; Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; Nakagawa, Takao; Tsunematsu, Shoji; Otsuka, Kiyomi; Kanao, Kenichi; Yoshida, Seiji; Narasaki, Katsuhiro

2017-12-01

Mechanical cryocoolers for space applications are required to have high reliability to achieve long-term operation in orbit. ASTRO-H (Hitomi), the 6th Japanese X-ray astronomy mission, has a major scientific instrument onboard-the Soft X-ray Spectrometer (SXS) with several 20K-class two-stage Stirling (2ST) coolers and a 4K-class Joule Thomson (JT) cooler, which must operate for 3 years to ensure the lifetime of liquid helium as a cryogen for cooling of its detectors [1,2]. Other astronomical missions such as SPICA [3,4], LiteBIRD [5], and Athena [6] also have top requirements for these mechanical cryocoolers, including a 1K-class JT cooler to be operated for more than 3-5 years with no cryogen system. The reliability and lifetime of mechanical cryocoolers are generally understood to depend on (1) mechanical wear of the piston seal and valve seal, and (2) He working gas contaminated by impurity outgases, mainly H2O and CO2 released from the materials in the components of the cryocoolers. The second factor could be critical relative to causing blockage in the JT heat exchanger plumbing and the JT orifice or resulting in blockage in the Stirling regenerator and thereby degrading its performance. Thus, reducing the potential for outgassing in the cryocooler design and fabrication process, and predicting the total amount of outgases in the cryocooler are very important to ensure cryocooler lifetime and cooling performance in orbit. This paper investigates the outgas analysis of the 2ST and the 1K/4K-JT coolers for achieving a long lifetime. First, gas analysis was conducted for the materials and components of the mechanical cryocoolers, focusing on non-metallic materials as impurity gas sources. Then gas analysis of the mechanical wear effect of the piston seal materials and linear ball bearings was investigated. Finally, outgassing from a fully assembled cryocooler was measured to evaluate whether the outgas reduction process works properly to meet the requirement

Research on the drawing process with a large total deformation wires of AZ31 alloy

International Nuclear Information System (INIS)

Bajor, T; Muskalski, Z; Suliga, M

2010-01-01

Magnesium and their alloys have been extensively studied in recent years, not only because of their potential applications as light-weight engineering materials, but also owing to their biodegradability. Due to their hexagonal close-packed crystallographic structure, cold plastic processing of magnesium alloys is difficult. The preliminary researches carried out by the authors have indicated that the application of the KOBO method, based on the effect of cyclic strain path change, for the deformation of magnesium alloys, provides the possibility of obtaining a fine-grained structure material to be used for further cold plastic processing with large total deformation. The main purpose of this work is to present research findings concerning a detailed analysis of mechanical properties and changes occurring in the structure of AZ31 alloy wire during the multistage cold drawing process. The appropriate selection of drawing parameters and the application of multistep heat treatment operations enable the deformation of the AZ31 alloy in the cold drawing process with a total draft of about 90%.

Lattice-Like Total Perfect Codes

Directory of Open Access Journals (Sweden)

Araujo Carlos

2014-02-01

Full Text Available A contribution is made to the classification of lattice-like total perfect codes in integer lattices Λn via pairs (G, Φ formed by abelian groups G and homomorphisms Φ: Zn → G. A conjecture is posed that the cited contribution covers all possible cases. A related conjecture on the unfinished work on open problems on lattice-like perfect dominating sets in Λn with induced components that are parallel paths of length > 1 is posed as well.

Interrelation of changes in the total content of ozone in the northern hemisphere with the velocity of the stratosphere circumpolar vortex

Science.gov (United States)

Kolyada, Maria N.; Kashkin, Valentin B.

2004-12-01

Considering the high significance of the ozone for preservation and maintenance of the biosphere and the temperature balance of the atmosphere the investigation of the ozone layer is a very important part of the investigation of the planet"s atmosphere. In this work results of investigations of TOC variability in the Northern Hemisphere and the influence of variability of the circumpolar vortex rotation velocity on the ozone layer are presented. Mean values of total ozone concentration in the Northern Hemisphere (by satellite data) and rotation velocities of the circumpolar vortex are calculated for each month from February to April during 1998-2004. Also in this work the mechanism of the influence of the natural factors on TOC variability solar activity during the spring is suggested.

Coordinating Work with Groupware

DEFF Research Database (Denmark)

Pors, Jens Kaaber; Simonsen, Jesper

2003-01-01

One important goal of employing groupware is to make possible complex collaboration between geographically distributed groups. This requires a dual transformation of both technology and work practice. The challenge is to re­duce the complexity of the coordination work by successfully inte....... Using the CSCW frame­work of coordination mechanisms, we have elicited six general factors influencing the integration of the groupware application in two situations....

Quantum Mechanics/Molecular Mechanics Modeling of Enzymatic Processes: Caveats and Breakthroughs.

Science.gov (United States)

Quesne, Matthew G; Borowski, Tomasz; de Visser, Sam P

2016-02-18

Nature has developed large groups of enzymatic catalysts with the aim to transfer substrates into useful products, which enables biosystems to perform all their natural functions. As such, all biochemical processes in our body (we drink, we eat, we breath, we sleep, etc.) are governed by enzymes. One of the problems associated with research on biocatalysts is that they react so fast that details of their reaction mechanisms cannot be obtained with experimental work. In recent years, major advances in computational hardware and software have been made and now large (bio)chemical systems can be studied using accurate computational techniques. One such technique is the quantum mechanics/molecular mechanics (QM/MM) technique, which has gained major momentum in recent years. Unfortunately, it is not a black-box method that is easily applied, but requires careful set-up procedures. In this work we give an overview on the technical difficulties and caveats of QM/MM and discuss work-protocols developed in our groups for running successful QM/MM calculations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control mechanisms for ecological-economic systems

CERN Document Server

Burkov, Vladimir N; Shchepkin, Alexander V

2015-01-01

This monograph presents and analyzes the optimization, game-theoretic and simulation models of control mechanisms for ecological-economic systems. It is devoted to integrated assessment mechanisms for total risks and losses, penalty mechanisms, risk payment mechanisms, financing and costs compensation mechanisms for risk level reduction, sales mechanisms for risk level quotas, audit mechanisms, mechanisms for expected losses reduction, economic motivation mechanisms, optimization mechanisms for regional environmental (risk level reduction) programs, and mechanisms for authorities' interests coordination. The book is aiming at undergraduate and postgraduate students, as well as at experts in mathematical modeling and control of ecological economic, socioeconomic and organizational systems.

Klokwerk + study protocol: An observational study to the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects.

Science.gov (United States)

Loef, Bette; van Baarle, Debbie; van der Beek, Allard J; van Kerkhof, Linda W; van de Langenberg, Daniëlla; Proper, Karin I

2016-08-02

Night-shift work may cause severe disturbances in the worker's circadian rhythm, which has been associated with the onset of health problems and diseases. As a substantial part of the workforce is exposed to night-shift work, harmful aspects of night-shift work should not be overlooked. The aim of the Klokwerk + study is to study the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects. First, we will study the relation between night-shift work exposure and body weight and between night-shift work exposure and infection susceptibility. Second, we will examine the mechanisms linking night-shift work exposure to body weight and infection susceptibility, with a specific focus on sleep, physical activity, diet, light exposure, vitamin D level, and immunological factors. Lastly, we will focus on the identification of biomarkers for chronic circadian disturbance associated with night-shift work. The design of this study is a prospective observational cohort study consisting of 1,960 health care workers aged 18-65 years. The study population will consist of a group of night-shift workers and an equally sized group of non-night-shift workers. During the study, there will be two measurement periods. As one of the main outcomes of this study is infection susceptibility, the measurement periods will take place at approximately the first (September/October) (T0) and the last month (April/May) (T1, after 6 months) of the flu season. The measurements will consist of questionnaires, anthropometric measurements, a smartphone application to determine infection susceptibility, food diaries, actigraphy, light sensors, and blood sample analyses. The Klokwerk + study will contribute to the current need for high-quality data on the health effects of night-shift work and its underlying behavioral and physiological mechanisms. The findings can be the starting point for the development of interventions that

Klokwerk + study protocol: An observational study to the effects of night–shift work on body weight and infection susceptibility and the mechanisms underlying these health effects

Directory of Open Access Journals (Sweden)

Bette Loef

2016-08-01

Full Text Available Abstract Background Night–shift work may cause severe disturbances in the worker’s circadian rhythm, which has been associated with the onset of health problems and diseases. As a substantial part of the workforce is exposed to night–shift work, harmful aspects of night–shift work should not be overlooked. The aim of the Klokwerk + study is to study the effects of night–shift work on body weight and infection susceptibility and the mechanisms underlying these health effects. First, we will study the relation between night–shift work exposure and body weight and between night–shift work exposure and infection susceptibility. Second, we will examine the mechanisms linking night–shift work exposure to body weight and infection susceptibility, with a specific focus on sleep, physical activity, diet, light exposure, vitamin D level, and immunological factors. Lastly, we will focus on the identification of biomarkers for chronic circadian disturbance associated with night–shift work. Methods/design The design of this study is a prospective observational cohort study consisting of 1,960 health care workers aged 18–65 years. The study population will consist of a group of night–shift workers and an equally sized group of non–night–shift workers. During the study, there will be two measurement periods. As one of the main outcomes of this study is infection susceptibility, the measurement periods will take place at approximately the first (September/October (T0 and the last month (April/May (T1, after 6 months of the flu season. The measurements will consist of questionnaires, anthropometric measurements, a smartphone application to determine infection susceptibility, food diaries, actigraphy, light sensors, and blood sample analyses. Discussion The Klokwerk + study will contribute to the current need for high–quality data on the health effects of night–shift work and its underlying behavioral and physiological

The Effect of Work on Health and Work Ability

NARCIS (Netherlands)

S.M. Alavinia (Seyed Mahammad)

2008-01-01

textabstractIn many countries through the industrial world the population is aging. Despite an increased life expectancy, improved living conditions, and better health status, the average time people spend in paid work is decreasing. There are several mechanisms of withdrawal from the labor force

Energy balance and deformation mechanisms of duplexes

Science.gov (United States)

Mitra, Gautam; Boyer, Steven E.

A duplex consists of a series of imbricate faults that are asymptotic to a roof thrust and a floor thrust. Depending on the final orientations of the imbricate faults and the final position of the branch lines, a duplex may be hinterland-dipping, foreland-dipping, or an antiformal stack. The exact geometry depends on various factors such as the initial dimensions of the individual slices (horses), their lithology, the amount of displacement (normalized to size of horse) on each fault, and the mechanics of movement along each fault. The energy required in duplex formation can be determined by calculating the total work involved in emplacing each horse: this is given by where W t=W p+W b+W g+W iWp is the work involved in initiating and propagating a fracture. Wb is the work involved in basal sliding, which may be frictional or some form of ductile flow, Wg is the work done against gravity during the emplacement of the horse, and Wi is the work involved in the internal deformation of the horse. By calculating and comparing these work terms it is possible to predict the conditions under which the different types of duplexes will form. Normally, the development of a hinterland-dipping duplex is most likely. However, if deformation conditions are favorable, displacements on individual imbricate faults may be very large compared to the size of the horses, leading to the formation of either antiformal stacks or foreland-dipping duplexes.

Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

KAUST Repository

Wu, Ying

2013-05-06

In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

KAUST Repository

Wu, Ying; Li, Jichun

2013-01-01

In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

Microstructure and mechanical behavior of pulsed laser surface melted AISI D2 cold work tool steel

Science.gov (United States)

Yasavol, N.; Abdollah-zadeh, A.; Ganjali, M.; Alidokht, S. A.

2013-01-01

D2 cold work tool steel (CWTS) was subjected to pulse laser surface melting (PLSM) at constant frequency of 20 Hz Nd: YAG laser with different energies, scanning rate and pulse durations radiated to the surface. Characterizing the PLSM, with optical and field emission scanning electron microscopy, electron backscattered diffraction and surface hardness mapping technique was used to evaluate the microhardness and mechanical behavior of different regions of melting pool. Increasing laser energy and reducing the laser scanning rate results in deeper melt pool formation. Moreover, PLSM has led to entirely dissolution of the carbides and re-solidification of cellular/dendritic structure of a fine scale surrounded by a continuous interdendritic network. This caused an increase in surface microhardness, 2-4 times over that of the base metal.

Structure of Work Values of Millennial Generation and Mechanism of Its Impact on Work Behavior%新生代员工工作价值观结构及其对工作行为的影响机理

Institute of Scientific and Technical Information of China (English)

李燕萍; 侯烜方

2012-01-01

In recent years, the problem of workplace conflict caused by the employees of millennial generation due to differences in work values lead toincreasing widespread public attention. Many studies focus only on some of the characteristics and its influencing factors in the values of the employees of millennialgeneration, but the literature of system specification to build the overall structure of the employees＇ work values of millennial generation is very uncommon. At the same time, the mediating variables between work values and work behavior defined and the theoretical explanation of the mechanism of action are still controversial. This paper aims to construct the structural features of the employees＇ work values of millennial generation, and in-depth analysis of the relationship between work values and work behavior of the employees of millennial generation, and to explore the mechanism of employees values of millennial generationimpacting on their work behavior through the mediating variables of the work pref- erences, and thus to provide a reference for the organization of management and institution building of the employees of millennial generation. With the characteristics that the Internet can be recorded and the data can be analyzed in this study, we gathered the community views on the comments of thework values and work behavior records of millennial generation and the variety of newspaper comments on the employees＇ work values of millennialgeneration, resulting in an overall understanding and analysis of the value structure of the millennial generation and the mechanism of its impact on the workbehavior. In this study, the candidate samples insist of the site investigation report, newspapers, magazines, and the commentary information. At the same time, the main evaluations include human resources managers, business leaders, the employees of millennial generation, as well as related experts and scholars. Based on the grounded, this paper builds the

An improved method for quantitatively measuring the sequences of total organic carbon and black carbon in marine sediment cores

Science.gov (United States)

Xu, Xiaoming; Zhu, Qing; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Jianping; Wang, Jianghai

2018-01-01

Understanding global carbon cycle is critical to uncover the mechanisms of global warming and remediate its adverse effects on human activities. Organic carbon in marine sediments is an indispensable part of the global carbon reservoir in global carbon cycling. Evaluating such a reservoir calls for quantitative studies of marine carbon burial, which closely depend on quantifying total organic carbon and black carbon in marine sediment cores and subsequently on obtaining their high-resolution temporal sequences. However, the conventional methods for detecting the contents of total organic carbon or black carbon cannot resolve the following specific difficulties, i.e., (1) a very limited amount of each subsample versus the diverse analytical items, (2) a low and fluctuating recovery rate of total organic carbon or black carbon versus the reproducibility of carbon data, and (3) a large number of subsamples versus the rapid batch measurements. In this work, (i) adopting the customized disposable ceramic crucibles with the microporecontrolled ability, (ii) developing self-made or customized facilities for the procedures of acidification and chemothermal oxidization, and (iii) optimizing procedures and carbon-sulfur analyzer, we have built a novel Wang-Xu-Yuan method (the WXY method) for measuring the contents of total organic carbon or black carbon in marine sediment cores, which includes the procedures of pretreatment, weighing, acidification, chemothermal oxidation and quantification; and can fully meet the requirements of establishing their highresolution temporal sequences, whatever in the recovery, experimental efficiency, accuracy and reliability of the measurements, and homogeneity of samples. In particular, the usage of disposable ceramic crucibles leads to evidently simplify the experimental scenario, which further results in the very high recovery rates for total organic carbon and black carbon. This new technique may provide a significant support for

Mechanical work as an indirect measure of subjective costs influencing human movement.

Directory of Open Access Journals (Sweden)

Karl E Zelik

Full Text Available To descend a flight of stairs, would you rather walk or fall? Falling seems to have some obvious disadvantages such as the risk of pain or injury. But the preferred strategy of walking also entails a cost for the use of active muscles to perform negative work. The amount and distribution of work a person chooses to perform may, therefore, reflect a subjective valuation of the trade-offs between active muscle effort and other costs, such as pain. Here we use a simple jump landing experiment to quantify the work humans prefer to perform to dissipate the energy of landing. We found that healthy normal subjects (N = 8 preferred a strategy that involved performing 37% more negative work than minimally necessary (P<0.001 across a range of landing heights. This then required additional positive work to return to standing rest posture, highlighting the cost of this preference. Subjects were also able to modulate the amount of landing work, and its distribution between active and passive tissues. When instructed to land softly, they performed 76% more work than necessary (P<0.001, with a higher proportion from active muscles (89% vs. 84%, P<0.001. Stiff-legged landings, performed by one subject for demonstration, exhibited close to the minimum of work, with more of it performed passively through soft tissue deformations (at least 30% in stiff landings vs. 16% preferred. During jump landings, humans appear not to minimize muscle work, but instead choose to perform a consistent amount of extra work, presumably to avoid other subjective costs. The degree to which work is not minimized may indirectly quantify the relative valuation of costs that are otherwise difficult to measure.

A dynamic allocation mechanism of delivering capacity in coupled networks

International Nuclear Information System (INIS)

Du, Wen-Bo; Zhou, Xing-Lian; Zhu, Yan-Bo; Zheng, Zheng

2015-01-01

Traffic process is ubiquitous in many critical infrastructures. In this paper, we introduce a mechanism to dynamically allocate the delivering capacity into the data-packet traffic model on the coupled Internet autonomous-system-level network of South Korea and Japan, and focus on its effect on the transport efficiency. In this mechanism, the total delivering capacity is constant and the lowest-load node will give one unit delivering capacity to the highest-load node at each time step. It is found that the delivering capacity of busy nodes and non-busy nodes can be well balanced and the effective betweenness of busy nodes with interconnections is significantly reduced. Consequently, the transport efficiency such as average traveling time and packet arrival rate is remarkably improved. Our work may shed some light on the traffic dynamics in coupled networks.

Effect of axial stress on the transient mechanical response of 20%, cold-worked Type 316 stainless-steel cladding

International Nuclear Information System (INIS)

Yamada, H.

1979-01-01

To understand the effects of the fuel-cladding mechanical interaction on the failure of 20% cold-worked Type 316 stainless-steel cladding during anticipated nuclear reactor transients, the transient mechanical response of the cladding was investigated using a transient tube burst method at a heating rate of 5.6 0 C/s and axial-to-hoop-stress ratios in the range of 1/2 to 2. The failure temperatures were observed to remain essentially constant for the transient tests at axial-to-hoop-stress ratios between 1/2 and 1, but to decrease with an increase in axial-to-hoop-stress ratios above unity. The uniform diametral strains to failure were observed to decrease monotonically with an increase in axial-to-hoop-stress ratio from 1/2 to 2, and in general, the uniform axial strains to failure were observed to increase with an increase in axial-to-hoop-stress ratio. The fracture of the cladding during thermal transients was found to be strongly affected by the maximum principal stress but not by the effective stress

Extended quantum mechanics

International Nuclear Information System (INIS)

Pavel Bona

2000-01-01

The work can be considered as an essay on mathematical and conceptual structure of nonrelativistic quantum mechanics which is related here to some other (more general, but also to more special and 'approximative') theories. Quantum mechanics is here primarily reformulated in an equivalent form of a Poisson system on the phase space consisting of density matrices, where the 'observables', as well as 'symmetry generators' are represented by a specific type of real valued (densely defined) functions, namely the usual quantum expectations of corresponding selfjoint operators. It is shown in this paper that inclusion of additional ('nonlinear') symmetry generators (i. e. 'Hamiltonians') into this reformulation of (linear) quantum mechanics leads to a considerable extension of the theory: two kinds of quantum 'mixed states' should be distinguished, and operator - valued functions of density matrices should be used in the role of 'nonlinear observables'. A general framework for physical theories is obtained in this way: By different choices of the sets of 'nonlinear observables' we obtain, as special cases, e.g. classical mechanics on homogeneous spaces of kinematical symmetry groups, standard (linear) quantum mechanics, or nonlinear extensions of quantum mechanics; also various 'quasiclassical approximations' to quantum mechanics are all sub theories of the presented extension of quantum mechanics - a version of the extended quantum mechanics. A general interpretation scheme of extended quantum mechanics extending the usual statistical interpretation of quantum mechanics is also proposed. Eventually, extended quantum mechanics is shown to be (included into) a C * -algebraic (hence linear) quantum theory. Mathematical formulation of these theories is presented. The presentation includes an analysis of problems connected with differentiation on infinite-dimensional manifolds, as well as a solution of some problems connected with the work with only densely defined unbounded

Changing Work, Changing Health: Can Real Work-Time Flexibility Promote Health Behaviors and Well-Being?

Science.gov (United States)

Moen, Phyllis; Kelly, Erin L.; Tranby, Eric; Huang, Qinlei

2012-01-01

This article investigates a change in the structuring of work time, using a natural experiment to test whether participation in a corporate initiative (Results Only Work Environment; ROWE) predicts corresponding changes in health-related outcomes. Drawing on job strain and stress process models, we theorize greater schedule control and reduced work-family conflict as key mechanisms linking this initiative with health outcomes. Longitudinal survey data from 659 employees at a corporate headquarters shows that ROWE predicts changes in health-related behaviors, including almost an extra hour of sleep on work nights. Increasing employees’ schedule control and reducing their work-family conflict are key mechanisms linking the ROWE innovation with changes in employees’ health behaviors; they also predict changes in well-being measures, providing indirect links between ROWE and well-being. This study demonstrates that organizational changes in the structuring of time can promote employee wellness, particularly in terms of prevention behaviors. PMID:22144731

Selection of software for mechanical engineering undergraduates

International Nuclear Information System (INIS)

Cheah, C. T.; Yin, C. S.; Halim, T.; Naser, J.; Blicblau, A. S.

2016-01-01

A major problem with the undergraduate mechanical course is the limited exposure of students to software packages coupled with the long learning curve on the existing software packages. This work proposes the use of appropriate software packages for the entire mechanical engineering curriculum to ensure students get sufficient exposure real life design problems. A variety of software packages are highlighted as being suitable for undergraduate work in mechanical engineering, e.g. simultaneous non-linear equations; uncertainty analysis; 3-D modeling software with the FEA; analysis tools for the solution of problems in thermodynamics, fluid mechanics, mechanical system design, and solid mechanics.

Selection of software for mechanical engineering undergraduates

Energy Technology Data Exchange (ETDEWEB)

Cheah, C. T.; Yin, C. S.; Halim, T.; Naser, J.; Blicblau, A. S., E-mail: ablicblau@swin.edu.au [Swinburne University of Technology, Faculty of Science Engineering and Technology, PO Box 218 Hawthorn, Victoria, Australia, 3122 (Australia)

2016-07-12

A major problem with the undergraduate mechanical course is the limited exposure of students to software packages coupled with the long learning curve on the existing software packages. This work proposes the use of appropriate software packages for the entire mechanical engineering curriculum to ensure students get sufficient exposure real life design problems. A variety of software packages are highlighted as being suitable for undergraduate work in mechanical engineering, e.g. simultaneous non-linear equations; uncertainty analysis; 3-D modeling software with the FEA; analysis tools for the solution of problems in thermodynamics, fluid mechanics, mechanical system design, and solid mechanics.

An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

Directory of Open Access Journals (Sweden)

L. R. Corr

2016-08-01

Full Text Available Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

Association Between Markers of Inflammation and Total Stroke by Hypertensive Status Among Women

Science.gov (United States)

Rexrode, Kathryn M.; Kotler, Gregory; Everett, Brendan M.; Glynn, Robert J.; Lee, I-Min; Buring, Julie E.; Ridker, Paul M.; Sesso, Howard D.

2016-01-01

BACKGROUND Markers of systemic inflammation (high-sensitivity C-reactive protein [hsCRP], soluble intercellular adhesion molecule 1 [sICAM-1], and fibrinogen) have been associated with a greater risk of total and ischemic stroke, in addition to elevated blood pressure. However, the role of these inflammatory markers on stroke pathophysiology by hypertension status is uncertain. METHODS Blood samples were collected and assayed for hsCRP, sICAM-1, and fibrinogen among 27,330 initially healthy women from the Women’s Health Study, and women were followed up from 1992 to 2013. Prior to randomization, the baseline questionnaire collected self-reported hypertension status, cardiovascular risk factors, and lifestyle factors. New cases of total, ischemic, and hemorrhagic stroke were updated annually through questionnaires and confirmed by medical records according to the National Survey of Stroke criteria. Multivariable Cox models estimated overall associations between each inflammatory marker and stroke and separately stratified by hypertension status. RESULTS We observed 629 incident total strokes over 477,278 person-years. In adjusted analyses, extreme quartiles of hsCRP and sICAM-1 were each associated with a significantly greater risk of total stroke (hsCRP: hazard ratios [HR] = 1.77, 95% confidence interval [CI]: 1.39–2.26; sICAM-1: HR = 1.28, 95% CI: 1.00–1.63). Fibrinogen was not associated with a significantly greater stroke risk. In analyses stratified by hypertension status, elevated hsCRP was associated with a nonstatistically significant greater risk of total stroke among prehypertensive and hypertensive women. CONCLUSIONS These data indicate that hsCRP and sICAM-1 are associated with hypertension status and stroke risk among women. Further work should examine the role of inflammatory markers on ischemic stroke subtypes and clarify mechanisms. PMID:27235695

Shift work as an oxidative stressor

OpenAIRE

Pasalar Parvin; Farahani Saeed; Sharifian Akbar; Gharavi Marjan; Aminian Omid

2005-01-01

Abstract Background Some medical disorders have higher prevalence in shift workers than others. This study was designed to evaluate the effect of night-shift-working on total plasma antioxidant capacity, with respect to the causative role of oxidative stress in induction of some of these disorders. Methods Two blood samples were taken from 44 workers with a rotational shift schedule, one after their day shift and one after their night shift. The total plasma antioxidant capacity of each worke...

China's Work Safety Report

Institute of Scientific and Technical Information of China (English)

Liang Jiakun

2005-01-01

@@ General Situation of China's Work Safety in 2004 In 2004, the national work safety situation remained stable as a whole and gained momentum to improve. The totality of accidents held the line and began to drop. The safety conditions in industrial,mining, and commercial/trading enterprises improved. Progress was made in ensuring work safety in the relevant industries and fields. The safety situation in most provinces (autonomous regions, municipalities directly under the Central Government) kept stable.

Total quality is people

International Nuclear Information System (INIS)

Vogel, C.E.

1991-01-01

Confronted by changing market conditions and increased global competition, in 1983 the Commercial Nuclear Fuel Division (CNFD) of Westinghouse Electric embarked on an ambitious plan to make total quality the centerpiece of its long-term business strategy. Five years later, the division's efforts in making continuous quality improvement a way of life among its more than 2,000 employees gained national recognition when it was named a charter recipient of the Malcolm Baldridge National Quality Award. What CNFD achieved during the 1980s was a cultural transformation, characterized by an empowered work force committed to a common vision. The company's quality program development strategy is described

Determination of total solutes in synfuel wastewaters

Energy Technology Data Exchange (ETDEWEB)

Wallace, J.R.; Bonomo, F.S.

1984-03-01

Efforts to investigate both lyophilization and the measurement of colligative properties as an indication of total solute content are described. The objective of the work described is to develop a method for measuring total dissolved material in retort wastewaters which is simple and rugged enough to be performed in a field laboratory in support of pollution control tests. The analysis should also be rapid enough to provide timely and pertinent data to the pollution control plant operator. To be of most value, the technique developed also should be applicable to other synfuel wastewaters, most of which contain similar major components as oil shale retort waters. 4 references, 1 table.

Worksite adjustments and work ability among employed cancer survivors.

Science.gov (United States)

Torp, Steffen; Nielsen, Roy A; Gudbergsson, Sævar B; Dahl, Alv A

2012-09-01

This study was conducted to determine how many cancer survivors (CSs) make worksite adjustments and what kinds of adjustments they make. Changes in work ability among employed CSs were explored, and clinical, sociodemographic, and work-related factors associated with the current total work ability were studied. CSs of the ten most common invasive types of cancer for men and women in Norway completed a mailed questionnaire 15-39 months after being diagnosed with cancer. Included in the analyses were all participants who worked both at the time of diagnosis and at the time of the survey and who had not changed their labor force status since diagnosis (n = 563). The current total work ability was compared to the lifetime best (0-10 score). Twenty-six percent of the employed CSs had made adjustments at work, and the most common adjustment was changing the number of work hours per week. Despite the fact that 31% and 23% reported reduced physical and mental work abilities, respectively, more than 90% of the CSs reported that they coped well with their work demands. The mean total work ability score was high (8.6) among both men and women. Being self-employed and working part-time at the time of diagnosis showed significant negative correlations with total work ability, while a favorable psychosocial work environment showed a significant positive correlation. CSs with low work ability were more often in contact with the occupational health service and also made more worksite adjustments than others. The prospects of future work life seem optimistic for Norwegian employed CSs who return to work relatively soon after primary treatment.

Insights into the working mechanism of water filtered infrared A (wIRA) irradiation on Chlamydia trachomatis serovar E

Science.gov (United States)

Kuratli, Jasmin; Pesch, Theresa; Marti, Hanna; Blenn, Christian; Borel, Nicole

2018-02-01

Infections with Chlamydia trachomatis are the major cause for infectious blindness and still represent the most common bacterial sexually transmitted disease worldwide. Considering the possible side effects of antibiotic therapy and the increasing threat of antibiotic resistance, alternative therapeutic strategies are needed. Previous studies showed a reduction of C. trachomatis infectivity after irradiation with water filtered infrared A alone (wIRA) or in combination with visible light (wIRA/VIS). In this study, we aimed to gain further insight into the working mechanism of wIRA/VIS by analyzing cytokine and chemokine levels of infected and non-infected HeLa cells following triple dose irradiation at 24, 36 and 40 hours post infection. Subsequently, we examined the influence of cytokines on irradiation and chlamydial infection using a cytokine/chemokine inhibitor (Azelastine) and by IL-6 and IL-8 gene silencing. A triple dose irradiation significantly reduced chlamydial infectivity in HeLa cells without inducing the chlamydial stress response. The reducing effect was present regardless of the addition of cycloheximide (CHX), a host protein synthesis inhibitor. Chlamydial infection, wIRA/VIS treatment and the combination of both revealed a similar release pattern of a subset of pro-inflammatory cytokines (IL-6, IL-8, RANTES, Serpin E1). The addition of Azelastine induced the chlamydial stress response in non-irradiated samples. This effect was even more pronounced in wIRA/VIS-treated conditions. Silencing of IL-6 and IL-8 resulted in a lower chlamydial infectivity. However, wIRA/VIS treatment of infected and silenced cells reduced the chlamydial infectivity similar to wIRA/VIS treated control cells. Further studies are needed to elucidate the working mechanism of wIRA/VIS.

Mental Imagery and Visual Working Memory

Science.gov (United States)

Keogh, Rebecca; Pearson, Joel

2011-01-01

Visual working memory provides an essential link between past and future events. Despite recent efforts, capacity limits, their genesis and the underlying neural structures of visual working memory remain unclear. Here we show that performance in visual working memory - but not iconic visual memory - can be predicted by the strength of mental imagery as assessed with binocular rivalry in a given individual. In addition, for individuals with strong imagery, modulating the background luminance diminished performance on visual working memory and imagery tasks, but not working memory for number strings. This suggests that luminance signals were disrupting sensory-based imagery mechanisms and not a general working memory system. Individuals with poor imagery still performed above chance in the visual working memory task, but their performance was not affected by the background luminance, suggesting a dichotomy in strategies for visual working memory: individuals with strong mental imagery rely on sensory-based imagery to support mnemonic performance, while those with poor imagery rely on different strategies. These findings could help reconcile current controversy regarding the mechanism and location of visual mnemonic storage. PMID:22195024

Mental imagery and visual working memory.

Directory of Open Access Journals (Sweden)

Rebecca Keogh

Full Text Available Visual working memory provides an essential link between past and future events. Despite recent efforts, capacity limits, their genesis and the underlying neural structures of visual working memory remain unclear. Here we show that performance in visual working memory--but not iconic visual memory--can be predicted by the strength of mental imagery as assessed with binocular rivalry in a given individual. In addition, for individuals with strong imagery, modulating the background luminance diminished performance on visual working memory and imagery tasks, but not working memory for number strings. This suggests that luminance signals were disrupting sensory-based imagery mechanisms and not a general working memory system. Individuals with poor imagery still performed above chance in the visual working memory task, but their performance was not affected by the background luminance, suggesting a dichotomy in strategies for visual working memory: individuals with strong mental imagery rely on sensory-based imagery to support mnemonic performance, while those with poor imagery rely on different strategies. These findings could help reconcile current controversy regarding the mechanism and location of visual mnemonic storage.

Mental imagery and visual working memory.

Science.gov (United States)

Keogh, Rebecca; Pearson, Joel

2011-01-01

Visual working memory provides an essential link between past and future events. Despite recent efforts, capacity limits, their genesis and the underlying neural structures of visual working memory remain unclear. Here we show that performance in visual working memory--but not iconic visual memory--can be predicted by the strength of mental imagery as assessed with binocular rivalry in a given individual. In addition, for individuals with strong imagery, modulating the background luminance diminished performance on visual working memory and imagery tasks, but not working memory for number strings. This suggests that luminance signals were disrupting sensory-based imagery mechanisms and not a general working memory system. Individuals with poor imagery still performed above chance in the visual working memory task, but their performance was not affected by the background luminance, suggesting a dichotomy in strategies for visual working memory: individuals with strong mental imagery rely on sensory-based imagery to support mnemonic performance, while those with poor imagery rely on different strategies. These findings could help reconcile current controversy regarding the mechanism and location of visual mnemonic storage.

Simulation of drive of mechanisms, working in specific conditions

Science.gov (United States)

Ivanovskaya, A. V.; Rybak, A. T.

2018-05-01

This paper presents a method for determining the dynamic loads on the lifting actuator device other than the conventional methods, for example, ship windlass. For such devices, the operation of their drives is typical under special conditions: different environments, the influence of hydrometeorological factors, a high level of vibration, variability of loading, etc. Hoisting devices working in such conditions are not considered in the standard; however, relevant studies concern permissible parameters of the drive devices of this kind. As an example, the article studied the work deck lifting devices - windlass. To construct a model, the windlass is represented by a rod of the variable cross-section. As a result, a mathematical model of the longitudinal oscillations of such rod is obtained. Analytic dependencies have also been obtained to determine the natural frequencies of the lowest forms of oscillations, which are necessary and are the basis for evaluating the parameters of operation of this type of the device.

Externally predictive quantitative modeling of supercooled liquid vapor pressure of polychlorinated-naphthalenes through electron-correlation based quantum-mechanical descriptors.

Science.gov (United States)

Vikas; Chayawan

2014-01-01

For predicting physico-chemical properties related to environmental fate of molecules, quantitative structure-property relationships (QSPRs) are valuable tools in environmental chemistry. For developing a QSPR, molecular descriptors computed through quantum-mechanical methods are generally employed. The accuracy of a quantum-mechanical method, however, rests on the amount of electron-correlation estimated by the method. In this work, single-descriptor QSPRs for supercooled liquid vapor pressure of chloronaphthalenes and polychlorinated-naphthalenes are developed using molecular descriptors based on the electron-correlation contribution of the quantum-mechanical descriptor. The quantum-mechanical descriptors for which the electron-correlation contribution is analyzed include total-energy, mean polarizability, dipole moment, frontier orbital (HOMO/LUMO) energy, and density-functional theory (DFT) based descriptors, namely, absolute electronegativity, chemical hardness, and electrophilicity index. A total of 40 single-descriptor QSPRs were developed using molecular descriptors computed with advanced semi-empirical (SE) methods, namely, RM1, PM7, and ab intio methods, namely, Hartree-Fock and DFT. The developed QSPRs are validated using state-of-the-art external validation procedures employing an external prediction set. From the comparison of external predictivity of the models, it is observed that the single-descriptor QSPRs developed using total energy and correlation energy are found to be far more robust and predictive than those developed using commonly employed descriptors such as HOMO/LUMO energy and dipole moment. The work proposes that if real external predictivity of a QSPR model is desired to be explored, particularly, in terms of intra-molecular interactions, correlation-energy serves as a more appropriate descriptor than the polarizability. However, for developing QSPRs, computationally inexpensive advanced SE methods such as PM7 can be more reliable than

[Shift work and night work: what effect on blood pressure?].

Science.gov (United States)

Cassat, M; Wuerzner, G; Burnier, M

2015-09-09

Shift work has become more and more common for the last thirty years. By definition, shift work disturbs the circadian rhythm and the internal clock. Even if the pathophysiological mechanisms are not well understood, a greater cardiovascular risk has been attributed to shift work. Cross-sectional and cohort studies have identified an association between shift work and an elevated blood pressure. Shift workers also present a higher incidence of hypertension and progression than day workers. Unfortunately, the heterogeneity of the studies, the multiple confounding factors, as well as the complexity to achieve a suitable comparison group make it impossible to draw firm clinical evidence. Nevertheless, this population needs a medical follow-up focused on the cardiovascular risks and blood pressure.

5th European Conference on Mechanisms Science (EUCOMES)

CERN Document Server

Viadero, Fernando; New Trends in Mechanism and Machine Science : from Fundamentals to Industrial Applications

2015-01-01

This work presents the most recent research in the mechanism and machine science field and its applications. The topics covered include: theoretical kinematics, computational kinematics, mechanism design, experimental mechanics, mechanics of robots, dynamics of machinery, dynamics of multi-body systems, control issues of mechanical systems, mechanisms for biomechanics, novel designs, mechanical transmissions, linkages and manipulators, micro-mechanisms, teaching methods, history of mechanism science and industrial and non-industrial applications. This volume consists of the Proceedings of the 5th European Conference on Mechanisms Science (EUCOMES), that was held in Guimarães, Portugal, from September 16 – 20, 2014. The EUCOMES is the main forum for the European community working in Mechanisms and Machine Science.

Busy yet socially engaged: volunteering, work-life balance, and health in the working population.

OpenAIRE

Ramos Romualdo; Brauchli Rebecca; Bauer Georg; Wehner Theo; Hämmig Oliver

2015-01-01

OBJECTIVE To understand the relationship between volunteering and health in the overlooked yet highly engaged working population, adopting a contextualizing balance approach. We hypothesize that volunteering may function as a psychosocial resource, contributing to work-life balance and, ultimately, health. METHODS A total of 746 Swiss workers participated in an online survey; 35% (N = 264) were additionally volunteers in a nonprofit organization. We assessed volunteering, work-life balance...

Strong tough low-carbon bainite structural steels exposed to heat treatment and mechanical working

International Nuclear Information System (INIS)

Lauprecht, W.; Imgrund, H.; Coldren, P.

1975-01-01

A review of results of studying the mechanical properties and structure of extremely strong construction low-pearlite and pearlite-free steels subjected to thermomechanical processing (TMP) is presented. The development of TMP of low-pearlite and pearlite-free steels has led to creation of steel of the following composition: 0.06% of C; 1.8% of Mn; 0.3% of Mo; 0.05-0.09% of Nb. Depending on the kind of TMP the most important parameters of which are the temperature of the termination of rolling and the total deformation below 900 deg C, transformation in these steels occurs partially or completely in the intermediate domain. The increased density of dislocations of beinite structure affects substantially the increase in the yield limit. High degrees of squeezing at temperatures below 870 deg C promote formation of ferrite nuclei. The laboratory rolling demonstrates that by selecting the conditions of TMP one can control the mechanical properties of a steel. The sheets of 13 mm thick allow to obtain the guaranteed values of the yield limit of 70 kgf/mm 2 the transition temperature T 50 = -25 deg C, whereas after rolling under different conditions the low-temperature limit of cold shortness is - 125 deg C, and the yield limit - 45 kgf/mm 2 . As followed from the estimate of numerous industrial experiments, with sheets 20 mm thick in hot-rolled state one can obtain the yield limit no less than 50 kgf/mm 2 . On rolling mills that make possible to produce large deformation at low temperature these values can be increased. For instance, with sheets 30 mm thick one can obtain the yield limit of 56 kgf/mm 2 and the transition temperature of - 60 deg C. The dependence of the yield limit on the holding time in steel tempering is given. The steel possesses a considerable reserve of the increase of strength due to dispersion hardening, which after tempering at 600-625 deg C constitutes 8-12 kgf/mm 2 . Because of low carbon content, this steel is characterized by good

Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

International Nuclear Information System (INIS)

Lucero, J. F.; Rojas, J. I.

2016-01-01

Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

Energy Technology Data Exchange (ETDEWEB)

Lucero, J. F., E-mail: fernando.lucero@hoperadiotherapy.com.gt [Universidad Nacional de Costa Rica, Heredia (Costa Rica); Hope International, Guatemala (Guatemala); Rojas, J. I., E-mail: isaac.rojas@siglo21.cr [Centro Médico Radioterapia Siglo XXI, San José (Costa Rica)

2016-07-07

Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

The meaning of work and working life after cancer: an interview study

DEFF Research Database (Denmark)

Rasmussen, Dorte M; Elverdam, Beth

2008-01-01

BACKGROUND: Cancer survivors have diverse and complex patterns of return to work, but little attention has been given to individual experiences of returning to work. OBJECTIVES: To analyse the meaning of work and working life for cancer survivors over time. METHODS: Participant observation...... was carried out at a cancer rehabilitation centre. A total of 23 participants were interviewed twice. RESULTS: Cancer survivors try to get back to work after treatment and try to re-establish their former structure of everyday-life that is seen as a normal and healthy existence. Work contributes to creating...... the individual as a social being, partaking in social relations with others. Work plays a role in establishing the individual's identity. It is difficult for many to resume work. When they are unable to work, they establish new activities in everyday-life that give meaning to a life. In order to understand...

Shift work parameters and disruption of diurnal cortisol production in female hospital employees.

Science.gov (United States)

Hung, Eleanor Wai Man; Aronson, Kristan J; Leung, Michael; Day, Andrew; Tranmer, Joan

2016-01-01

Shift work is associated with an increased risk of cardiovascular diseases (CVD). Disruption of cortisol production is a potential underlying mechanism. This study explored the associations of diurnal quantity and pattern of cortisol production in relation to (1) current shift work status (exclusive day versus rotating days and nights), (2) years of past shift work and (3) parameters of rotating shift work (timing, length and intensity). Female hospital employees (160 day workers and 168 rotating shift workers) from southeastern Ontario, Canada, participated in a cross-sectional study. Participants completed a baseline questionnaire and measures of body height, weight, and waist circumference were taken. Midstream urine samples were collected over two separate 24-hour periods to measure creatinine-adjusted cortisol. Total diurnal cortisol production and pattern were described with two measures of the area under the curve. The effect of shift work on cortisol was modeled using multivariable linear regression analyses. Cortisol production in day workers and shift workers on their day shift were similar; however, shift workers on the night shift had flatter diurnal cortisol curves and produced less cortisol. This suggests that night work is associated with an acute attenuation of cortisol production.

Stakeout electronic total station construction layout boring of the experience and precision

International Nuclear Information System (INIS)

Xu Zhiqiang

2012-01-01

Electronic total station can simultaneously measure angle and distance, together with the appropriate calculation methods and operating skills, able to efficiently complete the survey work, this paper based on practical experience, theoretical analysis, based on total station introduced in setting out a few boring in the skills and the measurement of total station in the construction layout for accuracy. (authors)

Educating the Public about the 2017 Total Solar Eclipse

Science.gov (United States)

Pasachoff, Jay M.

2017-01-01

On behalf of the International Astronomical Union's Working Group on Solar Eclipses, I have long worked to bring knowledge about eclipses and how to observe the safely to the people of the various countries from which partial, annular, or total solar eclipses are visible. In 2017, we have first a chance to educate the people of South America on the occasion of the February 26 annular eclipse through southern Chile and Argentina that is partial throughout almost the entire continent (and an eclipse workshop will be held February 22-24 in Esquel, Argentina: http://sion.frm.utn.edu.ar/WDEAII) and then a chance to educate the 300 million people of the United States and others in adjacent countries as far south as northern South America about the glories of totality and how to observe partial phases. Our website, a compendium of links to information about maps, safe observing, science, and more is at http://eclipses.info. We link to important mapping sites at EclipseWise.com, GreatAmericanEclipse.com, and http://xjubier.free.fr/en/site_pages/solar_eclipses/xSE_GoogleMap3.php?Ecl=+20170821&Acc=2&Umb=1&Lmt=1&Mag=1&Max=1, and information about cloudiness statistics at http://eclipsophile.com, as well as simulation sites at https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4314 and http://eyes.jpl.nasa.gov. The American Astronomical Society's task force on the 2017 eclipse has a website at http://eclipse.aas.org. We are working to disseminate accurate information about how and why to observe the total solar eclipse, trying among other things to head off common misinformation about the hazards of looking at the sun at eclipses or otherwise. About 12 million Americans live within the 70-mile-wide band of totality, and we encourage others to travel into it, trying to make clear the difference between even a 99% partial eclipse and a total eclipse, with its glorious Baily's beads, diamond rings, and totality that on this occasion lasts between 2 minutes and 2 minutes 40 seconds

Effect of mechanization level on manpower needs in forestry

Directory of Open Access Journals (Sweden)

Błuszkowska Urszula

2014-12-01

Full Text Available High work consumption in forest operations is above all the result of the character and task realization mode in works undertaken in forestry. Development of mechanization in forest management activities allows to considerably decrease manpower needs. In the present study, there were analyzed the possibilities of reduction of work consumption by improving the mechanization level of forest works. The method was developed to consider the following assessments: 1 variant W1 - basic option comprising factual work consumption values in works carried out on the area administered by the Regional Directorate of State Forests (RDLP; 2 W2 - showing the effect of 25% upgrade of works to a higher level of mechanization; 3 W3 - showing the effect of 50% upgrade of works to a higher level of mechanization; 4 W4 - comprising analogous calculations to those in variant W1 , but work consumption upgrading was 75%. Simulation calculations revealed considerable differences in needs for labor of different categories of forest workers. On the other hand, with increasing mechanization level, there increase the demands concerning worker qualifications, e.g. a harvester operator must be trained for about 2 years, and the training has to include both simulator exercises (first using software and next - harvester simulator and field work under supervision to gain sufficient experience. The introduction of higher levels of mechanization into forest operations, and hence considerable reduction of jobs for unqualified workers who are replaced by qualified employees, can help decreasing work consumption in forest operations.

Work-family culture, work-family interference and well-being at work : iIs it possible to distinguish between a positive and a negative process?

NARCIS (Netherlands)

Peeters, M.C.W.; Wattez, C.; Demerouti, E.; Regt, de W.

2009-01-01

Purpose – The purpose of this paper is to examine whether work-family (WF) interference functions as an explaining mechanism in the link between work-family culture and well-being, hereby distinguishing between a negative and a positive process. The negative, energy depleting process initiates from

Mechanisms of breast cancer risk in shift workers: association of telomere shortening with the duration and intensity of night work.

Science.gov (United States)

Samulin Erdem, Johanna; Notø, Heidi Ødegaard; Skare, Øivind; Lie, Jenny-Anne S; Petersen-Øverleir, Marte; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-08-01

Occupational factors such as shiftwork and especially night work that involves disruption of the circadian rhythm may contribute to increased breast cancer risk. Circadian disruption may also affect telomere length (TL). While short TL generally is associated with increased cancer risk, its association with breast cancer risk is inconclusive. We suggest that working schedules might be an important factor in assessment of effects of TL on breast cancer risk. Moreover, telomere shortening might be a potential mechanism for night work-related breast cancer. In this study, effects of shift work on TL and its association with breast cancer risk were investigated in a nested breast cancer case-control study of Norwegian nurses. TL was assessed by qPCR in DNA from 563 breast cancer patients and 619 controls. Here, we demonstrate that TL is affected by intensive night work schedules, as work with six consecutive night for a period of more than 5 years was associated with decreased telomere lengths (-3.18, 95% CI: -6.46 to -0.58, P = 0.016). Furthermore, telomere shortening is associated with increased breast cancer risk in workers with long periods of consecutive night shifts. Thus, nurses with longer telomere lengths had a lower risk for breast cancer if they had worked more than four (OR: 0.37, 95% CI: 0.16-0.79, P = 0.014) or five (OR: 0.31, 95% CI: 0.10-0.83, P = 0.029) consecutive night shifts for a period of 5 years or more. These data suggest that telomere shortening is associated with the duration and intensity of night work and may be a contributing factor for breast cancer risk among female shift workers. © 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Total elbow arthroplasty for primary osteoarthritis.

Science.gov (United States)

Schoch, Bradley S; Werthel, Jean-David; Sánchez-Sotelo, Joaquín; Morrey, Bernard F; Morrey, Mark

2017-08-01

Primary osteoarthritis of the elbow is a less common indication for total elbow arthroplasty (TEA). Higher complication rates in younger, active patients may offset short-term improvements in pain and function. The purpose of this study was to determine pain relief, functional outcomes, complications, and survival of TEA in this population. Between 1984 and 2011, 20 consecutive TEAs were performed for primary elbow osteoarthritis. Two patients died before the 2-year follow-up. Mean age at surgery was 68 years (range, 51-85 years). Outcome measures included pain, motion, Mayo Elbow Performance Score, satisfaction, complications, and reoperations. Mean follow-up was 8.9 years (range, 2-20 years). Three elbows sustained mechanical failures. Complications included intraoperative fracture (n = 2), wound irrigation and débridement (n = 1), bony ankylosis (n = 1), humeral loosening (n = 1), humeral component fracture (n = 1), and mechanical failure of a radial head component (n = 1). Fifteen elbows without mechanical failure were examined clinically. Pain improved from 3.6 to 1.5 (P  .05), with preoperative flexion contractures not improving. Mayo Elbow Performance Scores were available for 13 elbows without mechanical failure, averaging 81.5 points (range, 60-100 points); these were graded as excellent (n = 5), good (n = 2), and fair (n = 6). Subjectively, all patients without mechanical failure were satisfied. TEA represents a reliable surgical option for pain relief in patients with primary osteoarthritis. However, restoration of extension is not always obtained, indicating that more aggressive soft tissue releases or bony resection should be considered. Complications occurred in a large number of elbows, but mechanical failure was low considering the nature of this population and the length of follow-up. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Deformation quantization: Quantum mechanics lives and works in phase space

Directory of Open Access Journals (Sweden)

Zachos Cosmas K.

2014-01-01

A sampling of such intriguing techniques and methods has already been published in C. K. Zachos, Int Jou Mod Phys A17 297-316 (2002, and T. L. Curtright, D. B. Fairlie, and C. K. Zachos, A Concise Treatise on Quantum Mechanics in Phase Space, (Imperial Press & World Scientific, 2014.

Effects of prior cold work on corrosion and corrosive wear of copper in HNO3 and NaCl solutions

International Nuclear Information System (INIS)

Yin Songbo; Li, D.Y.

2005-01-01

Effects of prior cold work on corrosion and corrosive wear behavior of copper in 0.1 M HNO 3 and 3.5% NaCl solutions, respectively, were investigated using electrochemical tests, electron work function measurements, and sliding corrosive wear tests with and without cathodic protection. Optical microscope and SEM were employed to examine the microstructure and worn surfaces. It was shown that, in general, the prior cold work raised the corrosion rate, but the effect differed in different corrosive media. In both the solutions, pure mechanical wear decreased with an increase in cold work. The prior cold work had a significant influence on the corrosive wear of copper, depending on the corrosive solution and the applied load. In the 0.1 M HNO 3 solution, the ratio of the wear loss caused by corrosion-wear synergism to the total wear loss increased with the cold work and became saturated when the cold work reached a certain level. In the 3.5% NaCl solution, however, this ratio decreased initially and then became relatively stable with respect to the cold work. It was observed that wear of copper in the 3.5% NaCl solution was larger than that in 0.1 M HNO 3 solution, although copper showed lower corrosion rate in the former solution. The experimental observations and the possible mechanisms involved are discussed

Application of the Kyoto Mechanisms in Finland's climate policy. Report of the Finnish Committee on the Kyoto mechanisms

International Nuclear Information System (INIS)

2001-01-01

By the flexible mechanisms under the Kyoto Protocol are meant project-specific Joint Implementation, JI, intended for emissions reduction in the industrialised countries and the Clean Development Mechanism, CDM, designed for emissions reduction in the developing countries. Joint Implementation Projects can be found particularly in the economies-in-transition The flexible mechanisms under the Protocol also include Emissions Trading, ET, which States - and according to the view of several parties, enterprises, too - can conduct subject to rules to be later agreed upon in connection with emissions rights The international climate negotiations on the Kyoto Protocol and on drafting more detailed rules on the use of the mechanisms are still pending. In fact, the Working Group thinks that the uncertainties so far connected with the flexible mechanisms will lead to a situation in which the national climate policy must, at this stage, be primarily based on domestic reduction measures. Even if Finland were prepared to meet her climate policy obligations through domestic measures, there is, in the Working Group's opinion, skill reason to continue the preparations for the possibilities of using the Kyoto flexible mechanisms, too. The prime goal of the flexible mechanisms is an internationally cost-efficient climate policy, which creates the preconditions for the gradual tightening of emission limitations in a manner that will hinder economic and other societal activity as little as possible. Thus the flexible mechanisms can become more important during later commitment periods. According to model calculations, using the mechanisms would probably be inexpensive compared to the domestic emission reduction measures. It seems that the international markets for assigned amount units obtained through the use of the mechanisms would be big enough in view of the relatively limited immediate needs of the Finnish Climate Policy. The larger the group of countries and operators trading in

Protective effect of total flavones of Abelmoschus manihot L. Medic against poststroke depression injury in mice and its action mechanism.

Science.gov (United States)

Liu, Mei; Jiang, Qiu-Hong; Hao, Ji-Li; Zhou, Lan-Lan

2009-03-01

Total flavones of Abelmoschus manihot L. Medic (TFA) is the major active component isolated from the traditional Chinese herb Abelmoschus manihot L. Medic. We investigated the protective effect of TFA against poststroke depression (PSD) injury in mice and its action mechanism. A mouse model of PSD was induced by middle cerebral artery occlusion (MACO) 30 min/reperfusion, followed by isolation feeding and chronic unpredictable mild stress for 2 weeks. Treatment groups received TFA at three different doses (160, 80, and 40 mg/kg, p.o.) or fluoxetine (Flu, 2.5 mg/kg, p.o.) daily for 24 days. Change in behavior, brain tissue malondialdehyde (MDA) levels, and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured. The expression of brain-derived neurotrophic factor (BDNF) was detected by immunohistochemistry, and mRNA expression of BDNF and cAMP response element-binding protein (CREB) analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Treatment with TFA (160, 80, and 40 mg/kg) significantly ameliorated mice escape-directed behavioral impairment induced by PSD, markedly reduced MDA levels, and increased the activity of SOD, GSH-Px close to normal levels. TFA administration also attenuated PSD-induced neuronal death/losses, upregulated expression of BDNF both at mRNA and protein levels, as well as CREB mRNA levels. TFA had a protective effect against PSD injury in mice. Cardioprotection involves the inhibition of lipid peroxidation and upregulation of BDNF-CREB levels in the hippocampus, which may also be important mechanism of its antidepressants. This potential protection makes TFA a promising therapeutic agent for the PSD. (c) 2009 Wiley-Liss, Inc.

The Total Quality Management Model Department of Personnel State of Colorado,

Science.gov (United States)

A panel of three members will present the Total Quality Management model recently designed for the Department of Personnel, State of Colorado. This model was selected to increase work quality and productivity of the Department and to exemplify Governor Romer’s commitment to quality work within state government.

Models of Working Memory

National Research Council Canada - National Science Library

Miyake, Akira

1997-01-01

.... Understanding the mechanisms and structures underlying working memory is, hence, one of the most important scientific issues that need to be addressed to improve the efficiency and performance...

Association of serum total antioxidant capacity and total oxidant status with pain perception in patients with myofacial pain dysfunction.

Science.gov (United States)

Etoz, Osman A; Ataoglu, Hanife; Erel, Ozcan; Celik, Hakim; Herken, Emine Nur; Bayazit, Yildirim Ahmet

2009-01-01

We aimed to find out the association of total antioxidant capacity (TAC) and total oxidant status (TOS) with generalized pressure pain thresholds (PPT) of patients with myofacial pain dysfunction (MPD). PPT scores of patients with MPD (n = 37) and healthy individuals (n = 43) were measured on the hypothenar region of the hand using a mechanical algometer. Serum samples were collected and TAC and TOS were measured by novel methods. The TAC of patients was significantly lower than that of the control subjects. The difference between the TOS measurements of patients and control subjects was not significant. The PPT scores of the patients were significantly lower than that of control subjects. There may be an association between serum antioxidant capacity and MPD. Low serum TAC might also be related with pain perception.

Mechanics of fluid flow

CERN Document Server

Basniev, Kaplan S; Chilingar, George V 0

2012-01-01

The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry.  This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike.  It is a must-have for any engineer working in the oil and gas industry.

The impact of shift work on intensive care nurses' lives outside work

DEFF Research Database (Denmark)

Jensen, Hanne Irene; Larsen, Jette West; Thomsen, Tina Damgaard

2018-01-01

AIMS AND OBJECTIVES: To examine how shift work affects intensive care nurses' lives outside work. BACKGROUND: Shift work is unavoidable for many nurses. When attempting to minimise negative effects of shift work it is important to identify areas which affect nurses working shifts. DESIGN: A cross...... subsequently to plan interventions aimed at decreasing the negative effects. Interventions may include nurses having increased influence on their work schedules and education in sleep hygiene and dietary habits. This article is protected by copyright. All rights reserved.......AIMS AND OBJECTIVES: To examine how shift work affects intensive care nurses' lives outside work. BACKGROUND: Shift work is unavoidable for many nurses. When attempting to minimise negative effects of shift work it is important to identify areas which affect nurses working shifts. DESIGN: A cross......-sectional study. METHODS: A questionnaire survey among Danish intensive care nurses concerning experiences with shift work and family life, spare time activities, sleep and health. RESULTS: A total of 114 nurses (88%) participated. Shift work was found to influence the opportunities for spare time activities...

Shooting mechanisms in nature

NARCIS (Netherlands)

Sakes, Aimée; Wiel, van der Marleen; Henselmans, Paul W.J.; Leeuwen, van Johan L.; Dodou, Dimitra; Breedveld, Paul

2016-01-01

Background In nature, shooting mechanisms are used for a variety of purposes, including prey capture, defense, and reproduction. This review offers insight into the working principles of shooting mechanisms in fungi, plants, and animals in the light of the specific functional demands that these

Delayed Recall and Working Memory MMSE Domains Predict Delirium following Cardiac Surgery.

Science.gov (United States)

Price, Catherine C; Garvan, Cynthia; Hizel, Loren P; Lopez, Marcos G; Billings, Frederic T

2017-01-01

Reduced preoperative cognition is a risk factor for postoperative delirium. The significance for type of preoperative cognitive deficit, however, has yet to be explored and could provide important insights into mechanisms and prediction of delirium. Our goal was to determine if certain cognitive domains from the general cognitive screener, the Mini-Mental State Exam (MMSE), predict delirium after cardiac surgery. Patients completed a preoperative MMSE prior to undergoing elective cardiac surgery. Following surgery, delirium was assessed throughout ICU stay using the Confusion Assessment Method for ICU delirium and the Richmond Agitation and Sedation Scale. Cardiac surgery patients who developed delirium (n = 137) had lower total MMSE scores than patients who did not develop delirium (n = 457). In particular, orientation to place, working memory, delayed recall, and language domain scores were lower. Of these, only the working memory and delayed recall domains predicted delirium in a regression model adjusting for history of chronic obstructive pulmonary disease, age, sex, and duration of cardiopulmonary bypass. For each word not recalled on the three-word delayed recall assessment, the odds of delirium increased by 50%. For each item missed on the working memory index, the odds of delirium increased by 36%. Of the patients who developed delirium, 47% had a primary impairment in memory, 21% in working memory, and 33% in both domains. The area under the receiver operating characteristics curve using only the working memory and delayed recall domains was 0.75, compared to 0.76 for total MMSE score. Delirium risk is greater for individuals with reduced MMSE scores on the delayed recall and working memory domains. Research should address why patients with memory and executive vulnerabilities are more prone to postoperative delirium than those with other cognitive limitations.

Analysis of work ability and work-related physical activity of employees in a medium-sized business

OpenAIRE

Wilke, Christiane; Ashton, Philip; Elis, Tobias; Biallas, Bianca; Frob?se, Ingo

2015-01-01

Background Work-related physical activity (PA) and work ability are of growing importance in modern working society. There is evidence for age- and job-related differences regarding PA and work ability. This study analyses work ability and work-related PA of employees in a medium-sized business regarding age and occupation. Methods The total sample consists of 148 employees (116 men?78.38?% of the sample?and 32 women, accounting for 21.62?%; mean age: 40.85???10.07?years). 100 subjects (67.57...

Understanding work related musculoskeletal pain: does repetitive work cause stress symptoms?

DEFF Research Database (Denmark)

Bonde, J. P.; Mikkelsen, S.; Andersen, JH

2005-01-01

for development of regional pain in repetitive work, stress symptoms would likely be on the causal path. AIMS: To examine whether objective measures of repetitive monotonous work are related to occurrence and development of stress symptoms. METHODS: In 1994-95, 2033 unskilled workers with continuous repetitive...... Profile Inventory. RESULTS: Repetitive work, task cycle time, and quantified measures of repetitive upper extremity movements including force requirements were not related to occurrence of stress symptoms at baseline or development of stress symptoms during three years of follow up. CONCLUSIONS......: The findings do not indicate that repetitive work is associated with stress symptoms, but small effects cannot be ruled out. Thus the results question the importance of mental stress mechanisms in the causation of regional pain related to repetitive work. However, the findings should be interpreted...

Spring-like Ankle Foot Orthoses reduce the energy cost of walking by taking over ankle work.

Science.gov (United States)

Bregman, D J J; Harlaar, J; Meskers, C G M; de Groot, V

2012-01-01

In patients with central neurological disorders, gait is often limited by a reduced ability to push off with the ankle. To overcome this reduced ankle push-off, energy-storing, spring-like carbon-composite Ankle Foot Orthoses (AFO) can be prescribed. It is expected that the energy returned by the AFO in late stance will support ankle push-off, and reduce the energy cost of walking. In 10 patients with multiple sclerosis and stroke the energy cost of walking, 3D kinematics, joint power, and joint work were measured during gait, with and without the AFO. The mechanical characteristics of the AFO were measured separately, and used to calculate the contribution of the AFO to the ankle kinetics. We found a significant decrease of 9.8% in energy cost of walking when walking with the AFO. With the AFO, the range of motion of the ankle was reduced by 12.3°, and the net work around the ankle was reduced by 29%. The total net work in the affected leg remained unchanged. The AFO accounted for 60% of the positive ankle work, which reduced the total amount of work performed by the leg by 11.1% when walking with the AFO. The decrease in energy cost when walking with a spring-like energy-storing AFO in central neurological patients is not induced by an augmented net ankle push-off, but by the AFO partially taking over ankle work. Copyright © 2011 Elsevier B.V. All rights reserved.

The geometry of higher-order Lagrange spaces applications to mechanics and physics

CERN Document Server

Miron, Radu

1997-01-01