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Sample records for stresses engineering problem

Practical stress analysis in engineering design

CERN Document Server

Huston, Ronald

2008-01-01

Presents the application of engineering design and analysis based on the approach of understanding the physical characteristics of a given problem and then modeling the important aspects of the physical system. This book covers such topics as contact stress analysis, singularity functions, gear stresses, fasteners, shafts, and shaft stresses.
Use of frozen stress in extracting stress intensity factor distributions in three dimensional cracked body problems

Science.gov (United States)

Smith, C. W.

1992-01-01

The adaptation of the frozen stress photoelastic method to the determination of the distribution of stress intensity factors in three dimensional problems is briefly reviewed. The method is then applied to several engineering problems of practical significance.
Mechanics of materials formulas and problems : engineering mechanics 2

CERN Document Server

Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

2017-01-01

This book contains the most important formulas and more than 140 completely solved problems from Mechanics of Materials and Hydrostatics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Stress - Strain - Hooke’s Law - Tension and Compression in Bars - Bending of Beams - Torsion - Energy Methods - Buckling of Bars - Hydrostatics .
[Improving industrial microbial stress resistance by metabolic engineering: a review].

Science.gov (United States)

Fu, Ruiyan; Li, Yin

2010-09-01

Metabolic engineering is a technologic platform for industrial strain improvement and aims not only at modifying microbial metabolic fluxes, but also improving the physiological performance of industrial microbes. Microbes will meet multiple stresses in industrial processes. Consequently, elicited gene responses might result in a decrease in overall cell fitness and the efficiency of biotransformation. Thus, it is crucial to develop robust and productive microbial strains that can be integrated into industrial-scale bioprocesses. In this review, we focus on the progress of these novel methods and strategies for engineering stress-tolerance phenotypes referring to rational metabolic engineering and inverse metabolic engineering in recent years. In addition, we also address problems existing in this area and future research needs of microbial physiological functionality engineering.
Residual stress analysis for engineering applications by means of neutron diffraction

International Nuclear Information System (INIS)

Gnaeupel-Herold, T.; Brand, P.C.; Prask, H.J.

1999-01-01

Residual stresses originate from spatial differences in plastic deformation, temperature, or phase distribution, introduced by manufacturing processes or during service. Engineering parts and materials experience mechanical, thermal, and chemical loads during their service, and most of these loads introduce stresses that are superimposed on the already existing residual stresses. Residual stresses can therefore limit or improve life and strength of engineering parts; knowledge and understanding of these stresses is therefore critical for optimizing strength and durability. The economic and scientific importance of neutron diffraction residual stress analysis has led to an increasing number of suitable instruments worldwide. All of the major sources due in the next several years will have instruments for the sole purpose of performing residual stress and texture measurements. Recently, a dedicated, state-of-the-art diffractometer has been installed at the National Institute of Standards and Technology reactor. It has been used for a variety of measurements on basic and engineering stress problems. Among the most prominent examples that have been investigated in collaboration with industrial and academic partners are residual stresses in rails, weldments, and plasma-sprayed coatings
Residual Stress Analysis for Engineering Applications by Means of Neutron Diffraction

International Nuclear Information System (INIS)

Gndupel-Herold, Thomas; Brand, Paul C.; Prask, Henry J.

1999-01-01

The economic and scientific importance of neutron diffraction residual stress analysis has led to an increasing number of suitable instruments worldwide. Recently, a dedicated state-of-the-art diffractometer has been installed at the National Institute of Standards and Technology reactor. It has been used for a variety of measurements on basic and engineering stress problems. Among the most prominent examples that have been investigated are residual stresses in rails, weldments, and plasma-sprayed coatings
Computational problems in engineering

CERN Document Server

Mladenov, Valeri

2014-01-01

This book provides readers with modern computational techniques for solving variety of problems from electrical, mechanical, civil and chemical engineering. Mathematical methods are presented in a unified manner, so they can be applied consistently to problems in applied electromagnetics, strength of materials, fluid mechanics, heat and mass transfer, environmental engineering, biomedical engineering, signal processing, automatic control and more. • Features contributions from distinguished researchers on significant aspects of current numerical methods and computational mathematics; • Presents actual results and innovative methods that provide numerical solutions, while minimizing computing times; • Includes new and advanced methods and modern variations of known techniques that can solve difficult scientific problems efficiently.
Problem Solving Methods in Engineering Design

DEFF Research Database (Denmark)

Hartvig, Susanne C

1999-01-01

This short paper discusses typical engineering tasks and problem solving methods, based on a field study of engineering tasks at a Danish engineering firm. The field study has identified ten classes of design tasks and in this paper these classes are related to problem solving methods. The descri...
Application of a 2-D approximation technique for solving stress analyses problem in FEM

Directory of Open Access Journals (Sweden)

H Khawaja

2016-10-01

Full Text Available With the advent of computational techniques and methods like finite element method, complex engineering problems are no longer difficult to solve. These methods have helped engineers and designers to simulate and solve engineering problems in much more details than possible with experimental techniques. However, applying these techniques is not a simple task and require lots of acumen, understanding, and experience in obtaining a solution that is as close to an exact solution as possible with minimum computer resources. In this work using the finite element (FE method, stress analyzes of the low-pressure turbine of a small turbofan engine is carried out by employing two different techniques. Initially, a complete solid model of the turbine is prepared which is then finite element modelled with the eight-node brick element. Stresses are calculated using this model. Subsequently, the same turbine is modelled with four-node shell element for calculation of stresses. Material properties, applied loads (inertial, aerodynamic, and thermal, and constraints were same for both the cases. Authors have developed a “2-D approximation technique” to approximate a 3-D problem into a 2-D problem to study the saving invaluable computational time and resources. In this statistics technique, the 3-D domain of variable thickness is divided into many small areas of constant thickness. It is ensured that the value of the thickness for each sub-area is the correct representative thickness of that sub area, and it is within three sigma limit. The results revealed that technique developed is accurate, less time consuming and computational effort saving; the stresses obtained by 2-D technique are within five percent of 3-D results. The solution is obtained in CPU time which is six times less than the 3-D model. Similarly, the number of nodes and elements are more than ten times less than that of the 3-D model. ANSYS ® was used in this work.
Computational problems in science and engineering

CERN Document Server

Bulucea, Aida; Tsekouras, George

2015-01-01

This book provides readers with modern computational techniques for solving variety of problems from electrical, mechanical, civil and chemical engineering. Mathematical methods are presented in a unified manner, so they can be applied consistently to problems in applied electromagnetics, strength of materials, fluid mechanics, heat and mass transfer, environmental engineering, biomedical engineering, signal processing, automatic control and more.
Motion and Stress Analysis of Cam System for Marine Diesel Engine 93 KW

Directory of Open Access Journals (Sweden)

Christian Dhani Setiawan

2017-01-01

Full Text Available The developments of maritime sector in Indonesia shows increasing demand for ships. Especially ships with size of 30 GT has problem with low availability of the ship engine, which most of the ships still use non marine diesel engine as its main propulsion. The problem gives interest to make a step to improve by design marine diesel engine using reverse engineering method. Cam system of marine diesel engine design was needed to be calculate to select the material and the motion. The design of cam system needs study about the stress analysis in cam system to make sure the distribution of force and moment. The result of stress analysis was used to select material of components in cam system. The motion analysis result was used to be input data of stress analysis. The condition to obtain the stress of components was on maximum condition, its contain pressure, torque, rotation, and force. All component that calculated are camshaft, lifter (flat-tappet, push rod, rocker arm, spring, and valve. Each component was given two different materials and material selection was based on safety factor of each component. Material for camshaft and lifter were malleable cast iron, for push rod and rocker arm were mild steel, for spring was ASTM A231, for intake valve was steel JIS SUH3, and for exhaust valve was steel JIS SUH35. The result of motion analysis were angular velocity of camshaft with value was 2400 deg/sec, friction force between camshaft and lifter with maximum value was 125.393 N, and contact force between camshaft and lifter with maximum value was 845.307 N, and linear velocity of intake valve with maximum value was 696.573 mm/s, and linear velocity of exhaust valve was 463.734 mm/s.
Self-affirmation improves problem-solving under stress.

Science.gov (United States)

Creswell, J David; Dutcher, Janine M; Klein, William M P; Harris, Peter R; Levine, John M

2013-01-01

High levels of acute and chronic stress are known to impair problem-solving and creativity on a broad range of tasks. Despite this evidence, we know little about protective factors for mitigating the deleterious effects of stress on problem-solving. Building on previous research showing that self-affirmation can buffer stress, we tested whether an experimental manipulation of self-affirmation improves problem-solving performance in chronically stressed participants. Eighty undergraduates indicated their perceived chronic stress over the previous month and were randomly assigned to either a self-affirmation or control condition. They then completed 30 difficult remote associate problem-solving items under time pressure in front of an evaluator. Results showed that self-affirmation improved problem-solving performance in underperforming chronically stressed individuals. This research suggests a novel means for boosting problem-solving under stress and may have important implications for understanding how self-affirmation boosts academic achievement in school settings.
Self-affirmation improves problem-solving under stress.

Directory of Open Access Journals (Sweden)

J David Creswell

Full Text Available High levels of acute and chronic stress are known to impair problem-solving and creativity on a broad range of tasks. Despite this evidence, we know little about protective factors for mitigating the deleterious effects of stress on problem-solving. Building on previous research showing that self-affirmation can buffer stress, we tested whether an experimental manipulation of self-affirmation improves problem-solving performance in chronically stressed participants. Eighty undergraduates indicated their perceived chronic stress over the previous month and were randomly assigned to either a self-affirmation or control condition. They then completed 30 difficult remote associate problem-solving items under time pressure in front of an evaluator. Results showed that self-affirmation improved problem-solving performance in underperforming chronically stressed individuals. This research suggests a novel means for boosting problem-solving under stress and may have important implications for understanding how self-affirmation boosts academic achievement in school settings.
Residual stresses in Inconel 718 engine disks

Directory of Open Access Journals (Sweden)

Dahan Yoann

2014-01-01

Full Text Available Aubert&Duval has developed a methodology to establish a residual stress model for Inconel 718 engine discs. To validate the thermal, mechanical and metallurgical parts of the model, trials on lab specimens with specific geometry were carried out. These trials allow a better understanding of the residual stress distribution and evolution during different processes (quenching, ageing, machining. A comparison between experimental and numerical results reveals the residual stresses model accuracy. Aubert&Duval has also developed a mechanical properties prediction model. Coupled with the residual stress prediction model, Aubert&Duval can now propose improvements to the process of manufacturing in Inconel 718 engine disks. This model enables Aubert&Duval customers and subcontractors to anticipate distortions issues during machining. It could also be usedt to optimise the engine disk life.
Techniques for Analysing Problems in Engineering Projects

DEFF Research Database (Denmark)

Thorsteinsson, Uffe

1998-01-01

Description of how CPM network can be used for analysing complex problems in engineering projects.......Description of how CPM network can be used for analysing complex problems in engineering projects....
Expert vs. novice: Problem decomposition/recomposition in engineering design

Science.gov (United States)

Song, Ting

The purpose of this research was to investigate the differences of using problem decomposition and problem recomposition among dyads of engineering experts, dyads of engineering seniors, and dyads of engineering freshmen. Fifty participants took part in this study. Ten were engineering design experts, 20 were engineering seniors, and 20 were engineering freshmen. Participants worked in dyads to complete an engineering design challenge within an hour. The entire design process was video and audio recorded. After the design session, members participated in a group interview. This study used protocol analysis as the methodology. Video and audio data were transcribed, segmented, and coded. Two coding systems including the FBS ontology and "levels of the problem" were used in this study. A series of statistical techniques were used to analyze data. Interview data and participants' design sketches also worked as supplemental data to help answer the research questions. By analyzing the quantitative and qualitative data, it was found that students used less problem decomposition and problem recomposition than engineer experts in engineering design. This result implies that engineering education should place more importance on teaching problem decomposition and problem recomposition. Students were found to spend less cognitive effort when considering the problem as a whole and interactions between subsystems than engineer experts. In addition, students were also found to spend more cognitive effort when considering details of subsystems. These results showed that students tended to use dept-first decomposition and experts tended to use breadth-first decomposition in engineering design. The use of Function (F), Behavior (B), and Structure (S) among engineering experts, engineering seniors, and engineering freshmen was compared on three levels. Level 1 represents designers consider the problem as an integral whole, Level 2 represents designers consider interactions between
Problem Decomposition and Recomposition in Engineering Design: A Comparison of Design Behavior between Professional Engineers, Engineering Seniors, and Engineering Freshmen

Science.gov (United States)

Song, Ting; Becker, Kurt; Gero, John; DeBerard, Scott; DeBerard, Oenardi; Reeve, Edward

2016-01-01

The authors investigated the differences in using problem decomposition and problem recomposition between dyads of engineering experts, engineering seniors, and engineering freshmen. Participants worked in dyads to complete an engineering design challenge within 1 hour. The entire design process was video and audio recorded. After the design…
Problem Based Learning for engineering.

Science.gov (United States)

Kumar, Dinesh; Radcliffe, Pj

2017-07-01

the role of Problem Based Learning (PBL) is relative clear in domains such as medicine but its efficacy in engineering is as yet less certain. To clarify the role of PBL in engineering, a 3 day workshop was conducted for senior Brazilian engineering academics where they were given the theory and then an immersive PBL experience. One major purpose for running this workshop was for them to identify suitable courses where PBL could be considered. During this workshop, they were split in teams and given a diverse range of problems. At the conclusion of the workshop, a quantifiable survey was conducted and the results show that PBL can deliver superior educational outcomes providing the student group is drawn from the top 5% of the year 12 students, and that significantly higher resources are made available. Thus, any proposed PBL program in engineering must be able to demonstrate that it can meet these requirements before it can move forward to implementation.
Thought-evoking approaches in engineering problems

CERN Document Server

2014-01-01

In creating the value-added product in not distant future, it is necessary and inevitable to establish a holistic and though-evoking approach to the engineering problem, which should be at least associated with the inter-disciplinary knowledge and thought processes across the whole engineering spheres. It is furthermore desirable to integrate it with trans-disciplinary aspects ranging from manufacturing culture, through liberal-arts engineering, and industrial sociology. The thought-evoking approach can be exemplified and typified by representative engineering problems: unveiling essential features in ‘Tangential Force Ratio and Interface Pressure’, prototype development for ‘Bio-mimetic Needle’ and application of ‘Water-jet Machining to Artificial Hip Joint’, product innovation in ‘Heat Sink for Computer’, application of ‘Graph Theory’ to similarity evaluation of production systems, leverage among reciprocity attributes in ‘Industrial and Engineering Designs for Machine Enclosure’,...
Problems in event based engine control

DEFF Research Database (Denmark)

Hendricks, Elbert; Jensen, Michael; Chevalier, Alain Marie Roger

1994-01-01

Physically a four cycle spark ignition engine operates on the basis of four engine processes or events: intake, compression, ignition (or expansion) and exhaust. These events each occupy approximately 180° of crank angle. In conventional engine controllers, it is an accepted practice to sample...... the engine variables synchronously with these events (or submultiples of them). Such engine controllers are often called event-based systems. Unfortunately the main system noise (or disturbance) is also synchronous with the engine events: the engine pumping fluctuations. Since many electronic engine...... problems on accurate air/fuel ratio control of a spark ignition (SI) engine....

General engineering ethics and multiple stress of atomic energy engineering

International Nuclear Information System (INIS)

Takeda, Kunihiko

1999-01-01

The factors, by which the modern engineering ethics has been profoundly affected, were classified to three categories, namely mental blow, the destruction of human function and environment damage. The role of atomic energy engineering in the ethic field has been shown in the first place. It is pointed out that it has brought about the mental blow by the elucidation of universal truth and discipline and the functional disorder by the power supply. However, the direct effect of radiation to the human kinds is only a part of the stresses comparing to the accumulation of the social stress which should be taken into account of by the possibility of disaster and the suspicion of the atomic energy politics. An increase in the multiple stresses as well as the restriction of criticism will place obstacles on the promotion of atomic energy. (author)
General engineering ethics and multiple stress of atomic energy engineering

Energy Technology Data Exchange (ETDEWEB)

Takeda, Kunihiko [Shibaura Inst. of Tech., Tokyo (Japan)

1999-08-01

The factors, by which the modern engineering ethics has been profoundly affected, were classified to three categories, namely mental blow, the destruction of human function and environment damage. The role of atomic energy engineering in the ethic field has been shown in the first place. It is pointed out that it has brought about the mental blow by the elucidation of universal truth and discipline and the functional disorder by the power supply. However, the direct effect of radiation to the human kinds is only a part of the stresses comparing to the accumulation of the social stress which should be taken into account of by the possibility of disaster and the suspicion of the atomic energy politics. An increase in the multiple stresses as well as the restriction of criticism will place obstacles on the promotion of atomic energy. (author)
Problem solving in foundation engineering using foundationPro

CERN Document Server

Yamin, Mohammad

2016-01-01

This book is at once a supplement to traditional foundation engineering textbooks and an independent problem-solving learning tool. The book is written primarily for university students majoring in civil or construction engineering taking foundation analysis and design courses to encourage them to solve design problems. Its main aim is to stimulate problem solving capability and foster self-directed learning. It also explains the use of the foundationPro software, available at no cost, and includes a set of foundation engineering applications. Taking a unique approach, Dr. Yamin summarizes the general step-by-step procedure to solve various foundation engineering problems, illustrates traditional applications of these steps with longhand solutions, and presents the foundationPro solutions. The special structure of the book allows it to be used in undergraduate and graduate foundation design and analysis courses in civil and construction engineering. The book stands as valuable resource for students, faculty, ...
Group Design Problems in Engineering Design Graphics.

Science.gov (United States)

Kelley, David

2001-01-01

Describes group design techniques used within the engineering design graphics sequence at Western Washington University. Engineering and design philosophies such as concurrent engineering place an emphasis on group collaboration for the solving of design problems. (Author/DDR)
Applied Mathematical Problems in Engineering

Directory of Open Access Journals (Sweden)

Carlos Llopis-Albert

2016-10-01

Full Text Available There is a close relationship between engineering and mathematics, which has led to the development of new techniques in recent years. Likewise the developments in technology and computers have led to new ways of teaching mathematics for engineering students and the use of modern techniques and methods. This research aims to provide insight on how to deal with mathematical problems for engineering students. This is performed by means of a fuzzy set/Qualitative Comparative Analysis applied to conflict resolution of Public Participation Projects in support to the EU Water Framework Directive.
Providing solutions to engineering problems

International Nuclear Information System (INIS)

Connop, R.P.P.

1991-01-01

BNFL has acquired unique experience over a period of 40 years in specifying, designing and constructing spent fuel reprocessing and associated waste management plant. This experience is currently used to support a pound 5.5 billion capital investment programme. This paper reviews a number of engineering problems and their solutions to highlight BNFL experience in providing comprehensive specification, design and engineering and project management services. (author)
A Comparative Analysis of Software Engineering with Mature Engineering Disciplines Using a Problem-Solving Perspective

NARCIS (Netherlands)

Tekinerdogan, B.; Aksit, Mehmet; Dogru, Ali H.; Bicer, Veli

2011-01-01

Software engineering is compared with traditional engineering disciplines using a domain specific problem-solving model called Problem-Solving for Engineering Model (PSEM). The comparative analysis is performed both from a historical and contemporary view. The historical view provides lessons on the
Matrices in Engineering Problems

CERN Document Server

Tobias, Marvin

2011-01-01

This book is intended as an undergraduate text introducing matrix methods as they relate to engineering problems. It begins with the fundamentals of mathematics of matrices and determinants. Matrix inversion is discussed, with an introduction of the well known reduction methods. Equation sets are viewed as vector transformations, and the conditions of their solvability are explored. Orthogonal matrices are introduced with examples showing application to many problems requiring three dimensional thinking. The angular velocity matrix is shown to emerge from the differentiation of the 3-D orthogo
An Integrated Architecture for Engineering Problem Solving

National Research Council Canada - National Science Library

Pisan, Yusuf

1998-01-01

.... This thesis describes the Integrated Problem Solving Architecture (IPSA) that combines qualitative, quantitative and diagrammatic reasoning skills to produce annotated solutions to engineering problems...
Introductory Level Problems Illustrating Concepts in Pharmaceutical Engineering

Science.gov (United States)

McIver, Keith; Whitaker, Kathryn; De Delva, Vladimir; Farrell, Stephanie; Savelski, Mariano J.; Slater, C. Stewart

2012-01-01

Textbook style problems including detailed solutions introducing pharmaceutical topics at the level of an introductory chemical engineering course have been created. The problems illustrate and teach subjects which students would learn if they were to pursue a career in pharmaceutical engineering, including the unique terminology of the field,…
The Problem of Ensuring Reliability of Gas Turbine Engines

Science.gov (United States)

Nozhnitsky, Yu A.

2018-01-01

Requirements to advanced engines for civil aviation are discussing. Some significant problems of ensuring reliability of advanced gas turbine engines are mentioned. Special attention is paid to successful utilization of new materials and critical technologies. Also the problem of excluding failure of engine part due to low cycle or high cycle fatigue is discussing.
Comparison of Problem Solving from Engineering Design to Software Design

DEFF Research Database (Denmark)

Ahmed-Kristensen, Saeema; Babar, Muhammad Ali

2012-01-01

Observational studies of engineering design activities can inform the research community on the problem solving models that are employed by professional engineers. Design is defined as an ill-defined problem which includes both engineering design and software design, hence understanding problem...... solving models from other design domains is of interest to the engineering design community. For this paper an observational study of two software design sessions performed for the workshop on “Studying professional Software Design” is compared to analysis from engineering design. These findings provide...... useful insights of how software designers move from a problem domain to a solution domain and the commonalities between software designers’ and engineering designers’ design activities. The software designers were found to move quickly to a detailed design phase, employ co-.evolution and adopt...
Comparison of Problem Solving from Engineering Design to Software Design

DEFF Research Database (Denmark)

Ahmed-Kristensen, Saeema; Babar, Muhammad Ali

2012-01-01

solving models from other design domains is of interest to the engineering design community. For this paper an observational study of two software design sessions performed for the workshop on “Studying professional Software Design” is compared to analysis from engineering design. These findings provide......Observational studies of engineering design activities can inform the research community on the problem solving models that are employed by professional engineers. Design is defined as an ill-defined problem which includes both engineering design and software design, hence understanding problem...... useful insights of how software designers move from a problem domain to a solution domain and the commonalities between software designers’ and engineering designers’ design activities. The software designers were found to move quickly to a detailed design phase, employ co-.evolution and adopt...
Statics formulas and problems : engineering mechanics 1

CERN Document Server

Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

2017-01-01

This book contains the most important formulas and more than 160 completely solved problems from Statics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Equilibrium - Center of Gravity, Center of Mass, Centroids - Support Reactions - Trusses - Beams, Frames, Arches - Cables - Work and Potential Energy - Static and Kinetic Friction - Moments of Inertia.
Associations among everyday stress, critical life events, and sexual problems.

Science.gov (United States)

Bodenmann, Guy; Ledermann, Thomas; Blattner, Denise; Galluzzo, Claudia

2006-07-01

This study addresses the question of how stress is linked to sexual problems among women and men in close relationships. Psychological symptoms, relationship quality, internal daily stress (i.e., originating within the couple such as conflicts, worry for the partner), external daily stress (i.e., stress arising outside the couple such as job stress, stressful relatives, and so forth), and critical life events were examined with regard to their association with different sexual problems. The results support the hypotheses that (1) there is an incremental effect of stress on sexual problems after controlling for psychological symptoms and relationship quality, and that (2) it is primarily internal daily stress and in some cases critical life events rather than external daily stress that are related to sexual problems, particularly hypoactive sexual desire in women and men, sexual aversion in women, vaginismus in women, and premature ejaculation in men. Our findings indicate that the treatment of these sexual problems should address relationship issues and include a focus on helping individuals improve their stress management skills within their couple relationship.
Dynamics formulas and problems : engineering mechanics 3

CERN Document Server

Gross, Dietmar; Wriggers, Peter; Schröder, Jörg; Müller, Ralf

2017-01-01

This book contains the most important formulas and more than 190 completely solved problems from Kinetics and Hydrodynamics. It provides engineering students material to improve their skills and helps to gain experience in solving engineering problems. Particular emphasis is placed on finding the solution path and formulating the basic equations. Topics include: - Kinematics of a Point - Kinetics of a Point Mass- Dynamics of a System of Point Masses - Kinematics of Rigid Bodies - Kinetics of Rigid Bodies - Impact - Vibrations - Non-Inertial Reference Frames - Hydrodynamics .
Problem-based learning biotechnology courses in chemical engineering.

Science.gov (United States)

Glatz, Charles E; Gonzalez, Ramon; Huba, Mary E; Mallapragada, Surya K; Narasimhan, Balaji; Reilly, Peter J; Saunders, Kevin P; Shanks, Jacqueline V

2006-01-01

We have developed a series of upper undergraduate/graduate lecture and laboratory courses on biotechnological topics to supplement existing biochemical engineering, bioseparations, and biomedical engineering lecture courses. The laboratory courses are based on problem-based learning techniques, featuring two- and three-person teams, journaling, and performance rubrics for guidance and assessment. Participants initially have found them to be difficult, since they had little experience with problem-based learning. To increase enrollment, we are combining the laboratory courses into 2-credit groupings and allowing students to substitute one of them for the second of our 2-credit chemical engineering unit operations laboratory courses.
Problems of engineering education and their decision involving industry

OpenAIRE

R. P. Simonyants

2014-01-01

In Russia, the problems of engineering education are connected with political and economic upheavals of the late last century. At the same time, some leading engineering universities in Russia, such as the Bauman Moscow State Technical University (BMSTU) were resistant to the damaging effects of the crisis. But the methodology and experience of their effective work are insufficiently known.The problems of international engineering school development are also known. The first UNESCO World Repo...
Parentification, Stress, and Problem Behavior of Adolescents who have a Parent with Mental Health Problems.

Science.gov (United States)

Van Loon, Linda M A; Van de Ven, Monique O M; Van Doesum, Karin T M; Hosman, Clemens M H; Witteman, Cilia L M

2017-03-01

When adolescents live with a parent with mental illness, they often partly take over the parental role. Little is known about the consequences of this so-called parentification on the adolescents' internalizing and externalizing problems. This survey study examined this effect cross-sectionally and longitudinally in a sample of 118 adolescents living with a parent suffering from mental health problems. In addition, the study examined a possible indirect effect via perceived stress. Path analyses were used to examine the direct associations between parentification and problem behavior as well as the indirect relations via perceived stress. The results showed that parentification was associated with both internalizing and externalizing problems cross-sectionally, but it predicted only internalizing problems 1 year later. An indirect effect of parentification on adolescent internalizing and externalizing problems via perceived stress was found, albeit only cross-sectionally. These findings imply that parentification can be stressful for adolescents who live with a parent with mental health problems, and that a greater awareness of parentification is needed to prevent adolescents from developing internalizing problems. © 2015 Family Process Institute.
Teaching Agile Software Engineering Using Problem-Based Learning

Science.gov (United States)

El-Khalili, Nuha H.

2013-01-01

Many studies have reported the utilization of Problem-Based Learning (PBL) in teaching Software Engineering courses. However, these studies have different views of the effectiveness of PBL. This paper presents the design of an Advanced Software Engineering course for undergraduate Software Engineering students that uses PBL to teach them Agile…

Children with Autism: Sleep Problems and Mothers' Stress

Science.gov (United States)

Hoffman, Charles D.; Sweeney, Dwight P.; Lopez-Wagner, Muriel C.; Hodge, Danelle; Nam, Cindy Y.; Botts, Betsy H.

2008-01-01

Parenting a child with autism has been associated with maternal stress. The present investigation examined children's sleep difficulties and severity of autism along with mothers' sleep problems in relation to stress levels reported by mothers ( N = 72). Mothers' reports of their children's sleep problems were related to mothers' reports of their…
Intrinsic Cell Stress is Independent of Organization in Engineered Cell Sheets.

Science.gov (United States)

van Loosdregt, Inge A E W; Dekker, Sylvia; Alford, Patrick W; Oomens, Cees W J; Loerakker, Sandra; Bouten, Carlijn V C

2018-06-01

Understanding cell contractility is of fundamental importance for cardiovascular tissue engineering, due to its major impact on the tissue's mechanical properties as well as the development of permanent dimensional changes, e.g., by contraction or dilatation of the tissue. Previous attempts to quantify contractile cellular stresses mostly used strongly aligned monolayers of cells, which might not represent the actual organization in engineered cardiovascular tissues such as heart valves. In the present study, therefore, we investigated whether differences in organization affect the magnitude of intrinsic stress generated by individual myofibroblasts, a frequently used cell source for in vitro engineered heart valves. Four different monolayer organizations were created via micro-contact printing of fibronectin lines on thin PDMS films, ranging from strongly anisotropic to isotropic. Thin film curvature, cell density, and actin stress fiber distribution were quantified, and subsequently, intrinsic stress and contractility of the monolayers were determined by incorporating these data into sample-specific finite element models. Our data indicate that the intrinsic stress exerted by the monolayers in each group correlates with cell density. Additionally, after normalizing for cell density and accounting for differences in alignment, no consistent differences in intrinsic contractility were found between the different monolayer organizations, suggesting that the intrinsic stress exerted by individual myofibroblasts is independent of the organization. Consequently, this study emphasizes the importance of choosing proper architectural properties for scaffolds in cardiovascular tissue engineering, as these directly affect the stresses in the tissue, which play a crucial role in both the functionality and remodeling of (engineered) cardiovascular tissues.
Linked-Class Problem-Based Learning in Engineering: Method and Evaluation

Science.gov (United States)

Hunt, Emily M.; Lockwood-Cooke, Pamela; Kelley, Judy

2010-01-01

Problem-Based Learning (PBL) is a problem-centered teaching method with exciting potential in engineering education for motivating and enhancing student learning. Implementation of PBL in engineering education has the potential to bridge the gap between theory and practice. Two common problems are encountered when attempting to integrate PBL into…
EDITORIAL: Inverse Problems in Engineering

Science.gov (United States)

West, Robert M.; Lesnic, Daniel

2007-01-01

Presented here are 11 noteworthy papers selected from the Fifth International Conference on Inverse Problems in Engineering: Theory and Practice held in Cambridge, UK during 11-15 July 2005. The papers have been peer-reviewed to the usual high standards of this journal and the contributions of reviewers are much appreciated. The conference featured a good balance of the fundamental mathematical concepts of inverse problems with a diverse range of important and interesting applications, which are represented here by the selected papers. Aspects of finite-element modelling and the performance of inverse algorithms are investigated by Autrique et al and Leduc et al. Statistical aspects are considered by Emery et al and Watzenig et al with regard to Bayesian parameter estimation and inversion using particle filters. Electrostatic applications are demonstrated by van Berkel and Lionheart and also Nakatani et al. Contributions to the applications of electrical techniques and specifically electrical tomographies are provided by Wakatsuki and Kagawa, Kim et al and Kortschak et al. Aspects of inversion in optical tomography are investigated by Wright et al and Douiri et al. The authors are representative of the worldwide interest in inverse problems relating to engineering applications and their efforts in producing these excellent papers will be appreciated by many readers of this journal.
Chemistry and the Internal Combustion Engine II: Pollution Problems.

Science.gov (United States)

Hunt, C. B.

1979-01-01

Discusses pollution problems which arise from the use of internal combustion (IC) engines in the United Kingdom (UK). The IC engine exhaust emissions, controlling IC engine pollution in the UK, and some future developments are also included. (HM)
Problem-Based Learning in Engineering Ethics Courses

Science.gov (United States)

Kirkman, Robert

2016-01-01

I describe the first stages of a process of design research in which I employ problem-based learning in a course in engineering ethics, which fulfills a requirement for students in engineering degree programs. The aim of the course is to foster development of particular cognitive skills contributing to moral imagination, a capacity to notice,…
Teaching problem-solving skills to nuclear engineering students

Science.gov (United States)

Waller, E.; Kaye, M. H.

2012-08-01

Problem solving is an essential skill for nuclear engineering graduates entering the workforce. Training in qualitative and quantitative aspects of problem solving allows students to conceptualise and execute solutions to complex problems. Solutions to problems in high consequence fields of study such as nuclear engineering require rapid and accurate analysis of the problems, design of solutions (focusing on public safety, environmental stewardship and ethics), solution execution and monitoring results. A three-month course in problem solving, modelling and simulation was designed and a collaborative approach was undertaken with instructors from both industry and academia. Training was optimised for the laptop-based pedagogy, which provided unique advantages for a course that includes modelling and simulation components. The concepts and tools learned as part of the training were observed to be utilised throughout the duration of student university studies and interviews with students who have entered the workforce indicate that the approaches learned and practised are retained long term.
Solution Tree Problem Solving Procedure for Engineering Analysis ...

African Journals Online (AJOL)

Illustrations are provided in the thermofluid engineering area to showcase the procedure's applications. This approach has proved to be a veritable tool for enhancing the problem-solving and computer algorithmic skills of engineering students, eliciting their curiosity, active participation and appreciation of the taught course.
The Co-Development of Parenting Stress and Childhood Internalizing and Externalizing Problems.

Science.gov (United States)

Stone, Lisanne L; Mares, Suzanne H W; Otten, Roy; Engels, Rutger C M E; Janssens, Jan M A M

Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems is related to the development of parenting stress in children aged 4-9. Mothers of 1582 children participated in three one-year interval data waves. Internalizing and externalizing problems as well as parenting stress were assessed by maternal self-report. Interrelated development of parenting with internalizing and externalizing problems was examined using Latent Growth Modeling. Directionality of effects was further investigated by using cross-lagged models. Parenting stress and externalizing problems showed a decrease over time, whereas internalizing problems remained stable. Initial levels of parenting stress were related to initial levels of both internalizing and externalizing problems. Decreases in parenting stress were related to larger decreases in externalizing problems and to the (stable) course of internalizing problems. Some evidence for reciprocity was found such that externalizing problems were associated with parenting stress and vice versa over time, specifically for boys. Our findings support the transactional model in explaining psychopathology.
HEPATIC TISSUE ENGINEERING (MODERN STATE OF THIS PROBLEM

Directory of Open Access Journals (Sweden)

Y.S. Gulay

2014-01-01

Full Text Available In this article it was discussed the problem of creation implanted hepatic tissue engineering designs as a modern stage of complex investigation for working out bioartifi cial liver support systems. It was determined that for the positive decision of numerous biological and technological problems it is necessary: to use matrices with determined properties, which mimic properties of hepatic extracellular matrix; to use technology for stereotype sowing of these matrices by both parenchymal and non-parenchymal hepatic cells and to improve the technologies for making and assembling of hepatic tissue-engineering designs.
Problem Based Learning in Engineering Education

DEFF Research Database (Denmark)

Dahms, Mona-Lisa; Sauerbier, Gabriele; Stubbe, Korinna

2006-01-01

This paper describes a recent EU-project from five European Institutions. The aim was the development and implementation of a new international Master’s programme for staff development, directed towards the introduction of Problem Based Learning methods in the field of engineering education...
Examining the Critical Thinking Dispositions and the Problem Solving Skills of Computer Engineering Students

Science.gov (United States)

Özyurt, Özcan

2015-01-01

Problem solving is an indispensable part of engineering. Improving critical thinking dispositions for solving engineering problems is one of the objectives of engineering education. In this sense, knowing critical thinking and problem solving skills of engineering students is of importance for engineering education. This study aims to determine…
Problems in steel industry for power engineering

International Nuclear Information System (INIS)

Dolbenko, E.T.; Kryanin, I.R.

1979-01-01

The main problems of steel industry in power engineering are considered. The effect of charge materials upon steel quality is analyzed. Radical dicision of the problem is the ensurance of power engineering plants with high quality original charge materials, which are quite pure according to impurities such as: iron melted from metallized charge or prereduced pellets. The usage of such materials considerably improves the complex of technological and service properties and structure of large responsible products: vessels of the reactor core, especially large shafts and others. For the most responsible power engineering dies it is necessary to smelt steel of 150-200 tons and above. The main direction of steel melting industry is quality steel melting in large 150-200 tons arc furnaces which are equipped with magnetic stirrer installations. It is marked that the branch of power engineering is equipped with unique installations of out-of-furnace steel refining. It is shown that further increase in the metal quality is possible when vacuum and electroslag technique of melting is used. It permits to reduce considerably the amount of sulphur, gases, nonmetallic inclusions, to increase the metal density, to remove zonal segregation in large steel ingots. The main problem in the field of usage of material, produced by new melting methods is the expansion of the product nomenclature and the development of technical conditions, reflecting the increase in material properties as a result of new technique application. Importance of development and introduction of new automation and testing methods in metallurgical processes is marked
Influence of Stress Shape Function on Analysis of Contact Problem Using Hybrid Photoelasticity

International Nuclear Information System (INIS)

Shin, Dongchul; Hawong, Jaisug

2013-01-01

In this research, a study on stress shape functions was conducted to analyze the contact stress problem by using a hybrid photoelasticity. Because the contact stress problem is generally solved as a half-plane problem, the relationship between two analytical stress functions, which are compositions of the Airy stress function, was similar to one of the crack problem. However, this relationship in itself could not be used to solve the contact stress problem (especially one with singular points). Therefore, to analyze the contact stress problem more correctly, stress shape functions based on the condition of two contact end points had to be considered in the form of these two analytical stress functions. The four types of stress shape functions were related to the stress singularities at the two contact end points. Among them, the primary two types used for the analysis of an O-ring were selected, and their validities were verified in this work
Subterranean stress engineering experiments

International Nuclear Information System (INIS)

Campbell, J.R.; Colgate, S.A.; Wheat, B.M.

1980-01-01

The state of stress in a subterranean rock mass has classically been assumed to be constant at best. In soil with a high clay content, preconsolidation and drainage methods can lead to more stable foundation material, but methods for engineering the stresses in large masses of rock are not well known. This paper shows the results from an experiment designed to alter the in situ rock stress field in an oil shale mine. This was done by hydrofracturing the rock by use of a packed-well injection system and then propping the crack open with a thixotropic gel, which slowly hardened to the consistency of cement. Successive hydrofracture and high-pressure grouting resulted in an overstressed region. Well-head injection pressures, surface tilts, injection rates, and subterranean strains were measured and recorded on floppy disk by a Z-80 microprocessor. The results were then transmitted to the large computer system at the Los Alamos Scientific Laboratory (LASL). To put the data in a more useful form, computer-generated movies of the tilts and strains were made by use of computer graphics developed at LASL. The purpose of this paper is to present results from the Single Large Instrumented Test conducted in the Colony Oil Shale Mine near Rifle, Colorado. 13 figures
Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants

Directory of Open Access Journals (Sweden)

Shabir H. Wani

2016-06-01

Full Text Available Abiotic stresses including drought, salinity, heat, cold, flooding, and ultraviolet radiation causes crop losses worldwide. In recent times, preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance. However, the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities. Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance. Recent investigations have shown that phytohormones, including the classical auxins, cytokinins, ethylene, and gibberellins, and newer members including brassinosteroids, jasmonates, and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants. In this review, we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance, besides their engineering for conferring abiotic stress tolerance in transgenic crops. We also describe recent successes in identifying the roles of phytohormones under stressful conditions. We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.
Report on the workshop on neutrons for engineering and its conclusions regarding the residual-stress diffractometer at the Australian Replacement Research Reactor

International Nuclear Information System (INIS)

2002-01-01

The purpose of the workshop was to: inform the Australian research organizations and universities of the capabilities of an engineering and materials science instrument; promote the use of neutron diffraction to map and investigate strains/stresses in materials and components for industrial applications and research; identify the future needs and opportunities in this area; present the options for a stress mapping diffractometer at the Replacement Research Reactor and receive feedback on these options; identify the ancillary equipment and facilities required. Presented papers and discussions at the workshop indicated that there are a number of important benefits to Australia in the building of a first-class instrument for materials science and engineering and many residual stress-related problems in a wide variety of fields in Australia, such as the manufacturing industries, mining, oil and gas, rail transport, defense and life extension. Stress scanning provides another tool for solving problems to complement facilities at the major research institutes, CSIRO, AMIRA, DSTO, ANSTO and the universities. It will create a regional pool of experts who may tap into the pool of expertise internationally. The turn around time for tests for Australian customers will be reduced thus avoiding having to go overseas to have the tests performed. From an educational perspective the instrument will build expertise in Australia and will help to attract graduates into engineering. A detailed list of the attendees and affiliations is in Appendix C
Improved structural integrity through advances in reliable residual stress measurement: the impact of ENGIN-X

Science.gov (United States)

Edwards, L.; Santisteban, J. R.

The determination of accurate reliable residual stresses is critical to many fields of structural integrity. Neutron stress measurement is a non-destructive technique that uniquely provides insights into stress fields deep within engineering components and structures. As such, it has become an increasingly important tool within engineering, leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise lifing procedures. This paper describes the likely impact of the next generation of dedicated engineering stress diffractometers currently being constructed and the utility of the technique using examples of residual stresses both beneficial and detrimental to structural integrity.
Engineering surveying theory and examination problems for students

CERN Document Server

Schofield, W

2013-01-01

Engineering Surveying: Theory and Examination Problems for Students, Volume 1, Third Edition discusses topics concerning engineering surveying techniques and instrumentations. The book is comprised of eight chapters that cover several concerns in engineering survey. Chapter 1 discusses the basic concepts of surveying. Chapter 2 deals with simple and precise leveling, while Chapter 3 covers earthworks. The book also talks about the theodolite and its applications, and then discusses optical distance measurement. Curves, underground and hydrographic surveying, and aspects of dimensional control
Transient thermal stress problem for a circumferentially cracked hollow cylinder

Science.gov (United States)

Nied, H. F.; Erdogan, F.

1982-01-01

The transient thermal stress problem for a hollow elasticity cylinder containing an internal circumferential edge crack is considered. It is assumed that the problem is axisymmetric with regard to the crack geometry and the loading, and that the inertia effects are negligible. The problem is solved for a cylinder which is suddenly cooled from inside. First the transient temperature and stress distributions in an uncracked cylinder are calculated. By using the equal and opposite of this thermal stress as the crack surface traction in the isothermal cylinder the crack problem is then solved and the stress intensity factor is calculated. The numerical results are obtained as a function of the Fourier number tD/b(2) representing the time for various inner-to-outer radius ratios and relative crack depths, where D and b are respectively the coefficient of diffusivity and the outer radius of the cylinder.

Stress moderates the relationships between problem-gambling severity and specific psychopathologies.

Science.gov (United States)

Ronzitti, Silvia; Kraus, Shane W; Hoff, Rani A; Potenza, Marc N

2018-01-01

The purpose of this study was to examine the extent to which stress moderated the relationships between problem-gambling severity and psychopathologies. We analyzed Wave-1 data from 41,869 participants of the National Epidemiologic Survey of Alcohol and Related Conditions (NESARC). Logistic regression showed that as compared to a non-gambling (NG) group, individuals at-risk gambling (ARG) and problem gambling (PPG) demonstrated higher odds of multiple Axis-I and Axis-II disorders in both high- and low-stress groups. Interactions odds ratios were statistically significant for stress moderating the relationships between at-risk gambling (versus non-gambling) and Any Axis-I and Any Axis-II disorder, with substance-use and Cluster-A and Cluster-B disorders contributing significantly. Some similar patterns were observed for pathological gambling (versus non-gambling), with stress moderating relationships with Cluster-B disorders. In all cases, a stronger relationship was observed between problem-gambling severity and psychopathology in the low-stress versus high-stress groups. The findings suggest that perceived stress accounts for some of the variance in the relationship between problem-gambling severity and specific forms of psychopathology, particularly with respect to lower intensity, subsyndromal levels of gambling. Findings suggest that stress may be particularly important to consider in the relationships between problem-gambling severity and substance use and Cluster-B disorders. Published by Elsevier B.V.
Stress and emotional problems during pregnancy and excessive infant crying

NARCIS (Netherlands)

van der Wal, Marcel F.; van Eijsden, Manon; Bonsel, Gouke J.

2007-01-01

OBJECTIVE: There is evidence that stress and emotional problems during pregnancy are related to adverse health outcomes of the child at birth and in later life. The aim of this study was to determine the association between stress and emotional problems during pregnancy and excessive infant crying.
Exploration of Relationship Between Stress and Spirituality Characteristics of Male and Female Engineering Students: A Comprehensive Study.

Science.gov (United States)

Yadav, Radha; Khanna, Ashu; Singh, Dharmendra

2017-04-01

This observational paper endeavours to recognize the connection between spirituality and stress. Four types of indicators are utilized for the estimation of anxiety, vis-à-vis, behavioural indicators, emotional indicators, sleep indicators and personal habits. As per pre-documented theory, if spirituality is high within an individual, then his/her stress will be low and vice versa. In college, the stress of education and scoring grades influences the understudy. Information is gathered through a survey in the light of spirituality index and stress index. Findings prove that the indicators of the stress are more visible in female students. Apart from this, there has been not much substantial study in the area of stress and spirituality among college students. Hence, the main purpose of this study was to discuss the various types of stress and effects of spirituality on the engineering students belonging to the age group of 21-26 years, prioritizing the indicators of stress as per the gender of students. The entire study constituted of a sample group of 200 participants, and for the entire process, correlation analysis was used to find the relative relation between spirituality and stress among girls and boys. T test is used for rejection of the null hypothesis. The article focuses on the current issues that students have been facing in the twenty-first century. Result of the study showed that there is a negative relationship between the spirituality and stress of male and female students. Moreover, the article provides unique contribution to the literature and also offers suggestions for generating new research ideas that can be used to ameliorate the problems that plague individuals and organizations in today's world. This is the first article which covers the spirituality and stress of the engineering student and discusses the impact on young adults, as well as highlighting certain ways to overcome stress and enhance spirituality.
Acculturation stress and drinking problems among urban heavy drinking Latinos in the Northeast.

Science.gov (United States)

Lee, Christina S; Colby, Suzanne M; Rohsenow, Damaris J; López, Steven R; Hernández, Lynn; Caetano, Raul

2013-01-01

This study investigates the relationship between the level of acculturation and acculturation stress and the extent to which each predicts problems related to drinking. Hispanics who met criteria for hazardous drinking completed measures of acculturation, acculturation stress, and drinking problems. Sequential multiple regression was used to determine whether the levels of self-reported acculturation stress predicted concurrent alcohol problems after controlling for the predictive value of the acculturation level. Acculturation stress accounted for a significant variance in drinking problems, while adjusting for acculturation, income, and education. Choosing to drink in response to acculturation stress should be an intervention target with Hispanic heavy drinkers.
Evaluation of creative problem-solving abilities in undergraduate structural engineers through interdisciplinary problem-based learning

Science.gov (United States)

McCrum, Daniel Patrick

2017-11-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs. This interaction and engagement develops during their professional career but needs to be nurtured during their undergraduate studies. The objective of this paper is to present the strategies employed to engage higher order thinking in structural engineering students in order to help them solve complex problem-based learning (PBL) design scenarios presented by architecture students. The strategies employed were applied in the experimental setting of an undergraduate module in structural engineering at Queen's University Belfast in the UK. The strategies employed were active learning to engage with content knowledge, the use of physical conceptual structural models to reinforce key concepts and finally, reinforcing the need for hand sketching of ideas to promote higher order problem-solving. The strategies employed were evaluated through student survey, student feedback and module facilitator (this author) reflection. The strategies were qualitatively perceived by the tutor and quantitatively evaluated by students in a cross-sectional study to help interaction with the architecture students, aid interdisciplinary learning and help students creatively solve problems (through higher order thinking). The students clearly enjoyed this module and in particular interacting with structural engineering tutors and students from another discipline.
Problems of stress analysis of fuelling machine head components

International Nuclear Information System (INIS)

Mathur, D.D.

1975-01-01

The problem of stress analysis of fuelling machine head components are discussed. To fulfil the functional requirements, the components are required to have certain shapes where stress problems cannot be matched to a catalogue of pre-determined solutions. The areas where complex systems of loading due to hydrostatic pressure, weight, moments and temperature gradients coupled with the intricate shapes of the components make it difficult to arrive at satisfactory solutions. Particularly, the analysis requirements of the magazine housing, end cover, gravloc clamps and centre support are highlighted. An experimental stress analysis programme together with a theoretical finite element analysis is perhaps the answer. (author)
Stress and burnout in anaesthesia: a real world problem?

Science.gov (United States)

Rama-Maceiras, Pablo; Jokinen, Johanna; Kranke, Peter

2015-04-01

Stress and burnout have arisen as relevant problems to the healthcare workers and the health systems themselves. As anaesthesiologists work in stressful areas of the hospitals, we are exposed to these problems. In this review, we summarize recent studies regarding stress and burnout, exploring possible solutions. Almost 50% of anaesthesiologists scored positive for some of the burnout domains in different surveys, with one-third reporting high levels. The management of this problem not only needs an institutional but also an individual approach. Some recent randomized clinical trials and longitudinal studies suggest that there is some benefit of using several techniques to control stress, although benefits are still modest and most of the studies are based on transversal surveys and self-reported questionnaires. There is a lack of definitive evidence to guide the management of stress and burnout in medical professions in general and in anaesthesiology in particular. Longitudinal and interventional studies are needed to better determine ways of action. In the meantime, creating a positive work climate and institutional support as well as promoting control over one's job and the autonomy of employees are the most recommended strategies. Workers should also learn how to cope with stressors and practice personal strategies of wellness and resilience to fight against burnout.
Happy software developers solve problems better: psychological measurements in empirical software engineering.

Science.gov (United States)

Graziotin, Daniel; Wang, Xiaofeng; Abrahamsson, Pekka

2014-01-01

For more than thirty years, it has been claimed that a way to improve software developers' productivity and software quality is to focus on people and to provide incentives to make developers satisfied and happy. This claim has rarely been verified in software engineering research, which faces an additional challenge in comparison to more traditional engineering fields: software development is an intellectual activity and is dominated by often-neglected human factors (called human aspects in software engineering research). Among the many skills required for software development, developers must possess high analytical problem-solving skills and creativity for the software construction process. According to psychology research, affective states-emotions and moods-deeply influence the cognitive processing abilities and performance of workers, including creativity and analytical problem solving. Nonetheless, little research has investigated the correlation between the affective states, creativity, and analytical problem-solving performance of programmers. This article echoes the call to employ psychological measurements in software engineering research. We report a study with 42 participants to investigate the relationship between the affective states, creativity, and analytical problem-solving skills of software developers. The results offer support for the claim that happy developers are indeed better problem solvers in terms of their analytical abilities. The following contributions are made by this study: (1) providing a better understanding of the impact of affective states on the creativity and analytical problem-solving capacities of developers, (2) introducing and validating psychological measurements, theories, and concepts of affective states, creativity, and analytical-problem-solving skills in empirical software engineering, and (3) raising the need for studying the human factors of software engineering by employing a multidisciplinary viewpoint.
'Holistic Engineers' Observed through the Practice Looking-Glass

DEFF Research Database (Denmark)

Buch, Anders

2013-01-01

Many observers, policy makers, educationalists and industry representatives have called for reforms of engineering education that stress more ‘holistic’ and less disciplinary approaches to engineering problem solving (Buch 2012). And some reform initiatives within engineering education in Denmark...... and collaborative work space it turned out to be a forum for reactive and coordinative problem solving....... have indeed perused these ambitions. Problem based learning (PBL) has been implemented in engineering education at Aalborg University (Graff & Kolmos 2003) and a progressive ‘Design and Innovation’ engineering programme have been launched at the Technical University of Denmark (Jørgensen & Valderrama...
Problem-solving skills and hardiness as protective factors against stress in Iranian nurses.

Science.gov (United States)

Abdollahi, Abbas; Talib, Mansor Abu; Yaacob, Siti Nor; Ismail, Zanariah

2014-02-01

Nursing is a stressful occupation, even when compared with other health professions; therefore, it is necessary to advance our knowledge about the protective factors that can help reduce stress among nurses. The present study sought to investigate the associations among problem-solving skills and hardiness with perceived stress in nurses. The participants, 252 nurses from six private hospitals in Tehran, completed the Personal Views Survey, the Perceived Stress Scale, and the Problem-Solving Inventory. Structural Equation Modeling (SEM) was used to analyse the data and answer the research hypotheses. As expected, greater hardiness was associated with low levels of perceived stress, and nurses low in perceived stress were more likely to be considered approachable, have a style that relied on their own sense of internal personal control, and demonstrate effective problem-solving confidence. These findings reinforce the importance of hardiness and problem-solving skills as protective factors against perceived stress among nurses, and could be important in training future nurses so that hardiness ability and problem-solving skills can be imparted, allowing nurses to have more ability to control their perceived stress.
The Fertility Problem Inventory: measuring perceived infertility-related stress.

Science.gov (United States)

Newton, C R; Sherrard, W; Glavac, I

1999-07-01

To develop a reliable, valid instrument to evaluate perceived infertility-related stress. Prospective study. University-affiliated teaching hospital. Consecutively referred patients (1,153 women and 1,149 men) seen for infertility treatment. None. Participants' infertility-related stress was assessed by written questionnaire using the Fertility Problem Inventory. Current levels of anxiety, depression, and marital satisfaction also were determined. Women described greater global stress than men and higher specific stress in terms of social concerns, sexual concerns, and need for parenthood. Both men and women facing male infertility reported higher global stress and more social and sexual concerns than men and women experiencing female infertility. Social, sexual, and relationship concerns related to infertility were more effective predictors of depression and marital dissatisfaction than expressed needs for parenthood or attitudes toward child-free living. The Fertility Problem Inventory provides a reliable measure of perceived infertility-related stress and specific information on five separate domains of patient concern. Patterns of infertility-related stress differed depending on gender, fertility history, and infertility diagnosis. Among patients receiving treatment, social, sexual, and relationship concerns appear central to current distress. Counseling interventions that target these domains appear likely to offer maximal therapeutic benefit.
Ergonomic assessments of three Idaho National Engineering Laboratory cafeterias

Energy Technology Data Exchange (ETDEWEB)

Ostrom, L.T.; Romero, H.A.; Gilbert, B.G.; Wilhelmsen, C.A.

1993-01-01

The Idaho National Engineering Laboratory is a Department of Energy facility that performs a variety of engineering and research projects. EG G Idaho is the prime contractor for the laboratory and, as such, performs the support functions in addition to technical, research, and development functions. As a part of the EG G Idaho Industrial Hygiene Initiative, ergonomic assessments were conducted at three Idaho National Engineering Laboratory Cafeterias. The purposes of the assessments were to determine whether ergonomic problems existed in the work places and, if so, to make recommendations to improve the work place and task designs. The study showed there were ergonomic problems in all three cafeterias assessed. The primary ergonomic stresses observed included wrist and shoulder stress in the dish washing task, postural stress in the dish washing and food preparation tasks, and back stress in the food handling tasks.
Ergonomic assessments of three Idaho National Engineering Laboratory cafeterias

Energy Technology Data Exchange (ETDEWEB)

Ostrom, L.T.; Romero, H.A.; Gilbert, B.G.; Wilhelmsen, C.A.

1993-05-01

The Idaho National Engineering Laboratory is a Department of Energy facility that performs a variety of engineering and research projects. EG&G Idaho is the prime contractor for the laboratory and, as such, performs the support functions in addition to technical, research, and development functions. As a part of the EG&G Idaho Industrial Hygiene Initiative, ergonomic assessments were conducted at three Idaho National Engineering Laboratory Cafeterias. The purposes of the assessments were to determine whether ergonomic problems existed in the work places and, if so, to make recommendations to improve the work place and task designs. The study showed there were ergonomic problems in all three cafeterias assessed. The primary ergonomic stresses observed included wrist and shoulder stress in the dish washing task, postural stress in the dish washing and food preparation tasks, and back stress in the food handling tasks.
Problems of engineering education and their decision involving industry

Directory of Open Access Journals (Sweden)

R. P. Simonyants

2014-01-01

Full Text Available In Russia, the problems of engineering education are connected with political and economic upheavals of the late last century. At the same time, some leading engineering universities in Russia, such as the Bauman Moscow State Technical University (BMSTU were resistant to the damaging effects of the crisis. But the methodology and experience of their effective work are insufficiently known.The problems of international engineering school development are also known. The first UNESCO World Report on Engineering (2010 assesses the state of engineering education as follows: worldwide shortage of engineers is a threat to the development of society.Based on the analysis of the current state of engineering education in the world and tendencies of development an urgency of its modernization with the focus on the enhancement of practical component has been shown.Topical problems associated with innovations and modernization in engineering education in the field of aerospace technology were discussed at the first international forum, which was held in Beijing Beyhanskom University (BUAA on 8 - 9 September 2012. The author attended this forum and presented his impressions of its work. It was noted that the role of Russia in the global process to form and develop engineering education is ignored. This opinion sounded, generally, in all speakers' reports, apart from ours.The President BUAA, a Professor Jinpeng Huai, and a Professor Qiushi Li. talked about the problems of building the engineering education system in China. It was emphasized that in China a study of engineering education techniques was motivated by the fact that quality assurance of engineering education at U.S. universities does not meet requirements.Attention is drawn to Dr. David Wisler's report who is a representative of the U.S. aerospace industry (General Electric Aviation corporation, actively promoting networking technology "initiative CDIO».The assessment of the engineering education
Problem-solving skills and perceived stress among undergraduate students: The moderating role of hardiness.

Science.gov (United States)

Abdollahi, Abbas; Abu Talib, Mansor; Carlbring, Per; Harvey, Richard; Yaacob, Siti Nor; Ismail, Zanariah

2016-06-01

This study was designed to examine the relationships between problem-solving skills, hardiness, and perceived stress and to test the moderating role of hardiness in the relationship between problem-solving skills and perceived stress among 500 undergraduates from Malaysian public universities. The analyses showed that undergraduates with poor problem-solving confidence, external personal control of emotion, and approach-avoidance style were more likely to report perceived stress. Hardiness moderated the relationships between problem-solving skills and perceived stress. These findings reinforce the importance of moderating role of hardiness as an influencing factor that explains how problem-solving skills affect perceived stress among undergraduates.
Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

Science.gov (United States)

Flaga, Kazimierz; Furtak, Kazimierz

2015-03-01

Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.
Requirements Engineering as Creative Problem Solving: A Research Agenda for Idea Finding

OpenAIRE

Maiden, N.; Jones, S.; Karlsen, I. K.; Neill, R.; Zachos, K.; Milne, A.

2010-01-01

This vision paper frames requirements engineering as a creative problem solving process. Its purpose is to enable requirements researchers and practitioners to recruit relevant theories, models, techniques and tools from creative problem solving to understand and support requirements processes more effectively. It uses 4 drivers to motivate the case for requirements engineering as a creative problem solving process. It then maps established requirements activities onto one of the longest-esta...
Numerical simulations of coupled problems in engineering

CERN Document Server

2014-01-01

This book presents and discusses mathematical models, numerical methods and computational techniques used for solving coupled problems in science and engineering. It takes a step forward in the formulation and solution of real-life problems with a multidisciplinary vision, accounting for all of the complex couplings involved in the physical description. Simulation of multifaceted physics problems is a common task in applied research and industry. Often a suitable solver is built by connecting together several single-aspect solvers into a network. In this book, research in various fields was selected for consideration: adaptive methodology for multi-physics solvers, multi-physics phenomena and coupled-field solutions, leading to computationally intensive structural analysis. The strategies which are used to keep these problems computationally affordable are of special interest, and make this an essential book.
Novel perspectives for the engineering of abiotic stress tolerance in plants.

Science.gov (United States)

Cabello, Julieta V; Lodeyro, Anabella F; Zurbriggen, Matias D

2014-04-01

Adverse environmental conditions pose serious limitations to agricultural production. Classical biotechnological approaches towards increasing abiotic stress tolerance focus on boosting plant endogenous defence mechanisms. However, overexpression of regulatory elements or effectors is usually accompanied by growth handicap and yield penalties due to crosstalk between developmental and stress-response networks. Herein we offer an overview on novel strategies with the potential to overcome these limitations based on the engineering of regulatory systems involved in the fine-tuning of the plant response to environmental hardships, including post-translational modifications, small RNAs, epigenetic control of gene expression and hormonal networks. The development and application of plant synthetic biology tools and approaches will add new functionalities and perspectives to genetic engineering programs for enhancing abiotic stress tolerance. Copyright © 2013 Elsevier Ltd. All rights reserved.
Integrating Industry in Project Organized Problem Based Learning for Engineering Educations

DEFF Research Database (Denmark)

Nielsen, Kirsten M.

2006-01-01

This abstract deals with the challenge of establishing engineering student projects in collaboration with industry. Based on empirical results a set of advices for industrial collaboration in project oriented problem based learning are formulated......This abstract deals with the challenge of establishing engineering student projects in collaboration with industry. Based on empirical results a set of advices for industrial collaboration in project oriented problem based learning are formulated...

Promoting Collaborative Problem-Solving Skills in a Course on Engineering Grand Challenges

Science.gov (United States)

Zou, Tracy X. P.; Mickleborough, Neil C.

2015-01-01

The ability to solve problems with people of diverse backgrounds is essential for engineering graduates. A course on engineering grand challenges was designed to promote collaborative problem-solving (CPS) skills. One unique component is that students need to work both within their own team and collaborate with the other team to tackle engineering…
Electrical circuits in biomedical engineering problems with solutions

CERN Document Server

Keskin, Ali Ümit

2017-01-01

This authored monograph presents a comprehensive and in-depth analysis of electrical circuit theory in biomedical engineering, ideally suited as textbook for a course program. The book contains methods and theory, but the topical focus is placed on practical applications of circuit theory, including problems, solutions and case studies. The target audience primarily comprises researchers and experts in electrical engineering who intend to embark on biomedical applications. The book is also very well suited for graduate students in the field. .
Statics learning from engineering examples

CERN Document Server

Emri, Igor

2016-01-01

This textbook introduces and explains the basic concepts on which statics is based utilizing real engineering examples. The authors emphasize the learning process by showing a real problem, analyzing it, simplifying it, and developing a way to solve it. This feature teaches students intuitive thinking in solving real engineering problems using the fundamentals of Newton’s laws. This book also: · Stresses representation of physical reality in ways that allow students to solve problems and obtain meaningful results · Emphasizes identification of important features of the structure that should be included in a model and which features may be omitted · Facilitates students' understanding and mastery of the "flow of thinking" practiced by professional engineers.
Acculturation Stress and Drinking Problems Among Urban Heavy Drinking Latinos in the Northeast

OpenAIRE

Lee, Christina S.; Colby, Suzanne M.; Rohsenow, Damaris J.; López, Steven R.; Hernández, Lynn; Caetano, Raul

2013-01-01

This study investigates the relationship between level of acculturation and acculturation stress, and the extent to which each predicts problems related to drinking. Hispanics who met criteria for hazardous drinking completed measures of acculturation, acculturation stress, and drinking problems. Sequential multiple regression was used to determine whether levels of self-reported acculturation stress predicted concurrent alcohol problems after controlling for the predictive value of accultura...
Parenting Stress and Child Behavior Problems: A Transactional Relationship across Time

Science.gov (United States)

Neece, Cameron L.; Green, Shulamite A.; Baker, Bruce L.

2012-01-01

Parenting stress and child behavior problems have been posited to have a transactional effect on each other across development. However, few studies have tested this model empirically. The authors investigated the relationship between parenting stress and child behavior problems from ages 3 to 9 years old among 237 children, 144 of whom were…
Stress, social support and problem drinking among women in poverty.

Science.gov (United States)

Mulia, Nina; Schmidt, Laura; Bond, Jason; Jacobs, Laurie; Korcha, Rachael

2008-08-01

Previous studies have found that stress contributes to problem drinking, while social support can buffer its effects. However, these studies are confined largely to middle-class and general populations. We extend what is known by examining how the unique stressors and forms of social support experienced by women in poverty impact alcohol problems over a 4-year time-period. This prospective study used generalized estimating equations (GEE) transition modeling and four annual waves of survey data from 392 American mothers receiving Temporary Assistance for Needy Families (TANF) in a large Northern California county. We examined the effects of neighborhood disorder, stressful life events and economic hardship on psychological distress and problem drinking over time, and whether social support moderated these relationships for women in poverty. Neighborhood disorder and stressful life events increased significantly the risk for problem drinking, largely through their effect on psychological distress. We found little evidence, however, that social support buffers poor women from the effects of these stressors. Women in poverty are exposed to severe, chronic stressors within their communities and immediate social networks which increase vulnerability to psychological distress and problem drinking. The finding that social support does not buffer stress among these women may reflect their high level of exposure to stressors, as well as the hardships and scarce resources within their networks. If the 'private safety net' of the social network fails to provide a strong buffer, more effective environmental interventions that reduce exposure to stressors may be needed to prevent alcohol problems in poor women's lives.
Parenting stress among mothers of children with different physical, mental, and psychological problems

Directory of Open Access Journals (Sweden)

Awat Feizi

2014-01-01

Full Text Available Background: Parents of children with developmental problems are always bearing a load of stress. The aim of this study is to compare the stress in mothers of children with different disabilities to each other, considering their demographic background. Materials and Methods: This was a cross-sectional study conducted in Isfahan, Iran during 2012 on 285 mothers of 6-12 years old children with chronic physical disease, psychological disorder, and sensory-motor and mental problems. Abedin′s parenting stress questionnaire was used and obtained data were analyzed using multivariate analysis of variance or covariance as appropriate. Results: Mothers of children with sensory-motor mental and chronic physical problems experience more stress than mothers of children with psychological disorders (P < 0.05. The stress score of mothers of children with psychological disorders was lower than the other two groups. Also there was a significant difference between the score of mothers of children with chronic physical problems and mothers of children with psychological disorders regarding parent-child dysfunctional interaction (P < 0.01. A significant difference was observed in terms of stress among mothers of children with sensory-motor mental problems with different number of children (P < 0.05; also mothers of children with chronic physical problems in different levels of education have experienced different levels of parenting stress (P < 0.05 Conclusion: Due to high level of parenting stress among our studied samples, special education and early intervention are needed for parents in our study population in order to deepening their diagnostic knowledge and professional consultation on stress management
HEPATIC TISSUE ENGINEERING (MODERN STATE OF THIS PROBLEM)

OpenAIRE

Y.S. Gulay; M.E. Krasheninnikov; M.Y. Shagidulin; N.A. Onishchenko

2014-01-01

In this article it was discussed the problem of creation implanted hepatic tissue engineering designs as a modern stage of complex investigation for working out bioartifi cial liver support systems. It was determined that for the positive decision of numerous biological and technological problems it is necessary: to use matrices with determined properties, which mimic properties of hepatic extracellular matrix; to use technology for stereotype sowing of these matrices by both parenchymal and ...
The Washington Academy of Biomedical Engineering (WABME) Quarterly Workshops: Clinical Problems and Engineering Solutions

National Research Council Canada - National Science Library

Wong, Kenneth

2005-01-01

... University and Howard University. A prime component of WABME activities is a quarterly series of research workshops, which bring together problem-rich biomedical disciplines and solution-rich engineering and scientific disciplines...
Probabilistic analysis of structures involving random stress-strain behavior

Science.gov (United States)

Millwater, H. R.; Thacker, B. H.; Harren, S. V.

1991-01-01

The present methodology for analysis of structures with random stress strain behavior characterizes the uniaxial stress-strain curve in terms of (1) elastic modulus, (2) engineering stress at initial yield, (3) initial plastic-hardening slope, (4) engineering stress at point of ultimate load, and (5) engineering strain at point of ultimate load. The methodology is incorporated into the Numerical Evaluation of Stochastic Structures Under Stress code for probabilistic structural analysis. The illustrative problem of a thick cylinder under internal pressure, where both the internal pressure and the stress-strain curve are random, is addressed by means of the code. The response value is the cumulative distribution function of the equivalent plastic strain at the inner radius.
Reliability engineering: Old problems and new challenges

International Nuclear Information System (INIS)

Zio, E.

2009-01-01

The first recorded usage of the word reliability dates back to the 1800s, albeit referred to a person and not a technical system. Since then, the concept of reliability has become a pervasive attribute worth of both qualitative and quantitative connotations. In particular, the revolutionary social, cultural and technological changes that have occurred from the 1800s to the 2000s have contributed to the need for a rational framework and quantitative treatment of the reliability of engineered systems and plants. This has led to the rise of reliability engineering as a scientific discipline. In this paper, some considerations are shared with respect to a number of problems and challenges which researchers and practitioners in reliability engineering are facing when analyzing today's complex systems. The focus will be on the contribution of reliability to system safety and on its role within system risk analysis
Hydrostatic Pressure Project: Linked-Class Problem-Based Learning in Engineering

Science.gov (United States)

Davis, Freddie J.; Lockwood-Cooke, Pamela; Hunt, Emily M.

2011-01-01

Over the last few years, WTAMU Mathematics, Engineering and Science faculty has used interdisciplinary projects as the basis for implementation of a linked-class approach to Problem-Based Learning (PBL). A project that has significant relevance to engineering statics, fluid mechanics, and calculus is the Hydrostatic Pressure Project. This project…
Excel 2016 for engineering statistics a guide to solving practical problems

CERN Document Server

Quirk, Thomas J

2016-01-01

This book shows the capabilities of Microsoft Excel in teaching engineering statistics effectively. Similar to the previously published Excel 2013 for Engineering Statistics, this book is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical engineering problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in engineering courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However,Excel 2016 for Engineering Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and...
Investigating and developing engineering students' mathematical modelling and problem-solving skills

Science.gov (United States)

Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven

2015-09-01

How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced problem solvers, unaware of the importance of understanding the problem and exploring alternatives, and impeded by inappropriate beliefs, attitudes and expectations. Important impacts of the course belong to the metacognitive domain. The nature of the problems, the supervision and the follow-up lectures were emphasised as contributing to the impacts of the course, where students show major development. We discuss these empirical results in relation to a framework for mathematical thinking and the notion of cognitive apprenticeship. Based on the results, we argue that this kind of teaching should be considered in the education of all engineers.
Introduction to Problem Based Learning for Engineering Education

DEFF Research Database (Denmark)

Moesby, Egon; Rosenørn, Torben

2003-01-01

Documentation material and working papers for the workshop "Introduction to Problem Based Learning for Engineering Education" held at Chiang Mai University, Chiang Mai, Thailand, 6 - 10 October 2003. The material support the workshop where the participants go through a complete pre-planning cycle...
Welding problems in nuclear power engineering

International Nuclear Information System (INIS)

Zubchenko, A.S.

1986-01-01

The problems of welding industry in nuclear power plant engineering, mainly related to the improvement of molten bath protection, are considered. Development of new materials for welding electrodes, for cladding and welding fluxes, is pointed out. Production of the following equipment is brought to a commercial level: welding heads and welding machines for branch pipe welding, anticorrosion cladding, zonal thermal treatment, electron beam welding facilities for the welding and maintenance of turbineblades, equipment for nondestructive testing of welded joints
Investigation of Problem Solving Skills among 12th Grade Engineering Students

OpenAIRE

Shanta, Susheela

2017-01-01

US competitiveness in the 21st century global economy depends on a workforce that is science, technology, engineering and mathematics (STEM) literate, and has knowledge and skills to tackle complex technological problems. In response to the need for a STEM literate workforce equipped with 21st century skills there is a push for K-12 educational reform. STEM literacy is the ability to use content knowledge and skills in science, technology, engineering and math in solving human problems in a c...
Distress Tolerance Links Sleep Problems with Stress and Health in Homeless.

Science.gov (United States)

Reitzel, Lorraine R; Short, Nicole A; Schmidt, Norman B; Garey, Lorra; Zvolensky, Michael J; Moisiuc, Alexis; Reddick, Carrie; Kendzor, Darla E; Businelle, Michael S

2017-11-01

We examined associations between sleep problems, distress intolerance, and perceived stress and health in a convenience sample of homeless adults. Participants (N = 513, 36% women, Mage = 44.5 ±11.9) self-reported sleep adequacy, sleep duration, unintentional sleep during the daytime, distress tolerance, urban stress, and days of poor mental health and days of poor physical health over the last month. The indirect effects of sleep problems on stress and health through distress tolerance were examined using a non-parametric, bias-corrected bootstrapping procedure. Sleep problems were prevalent (eg, 13.0 ±11.4 days of inadequate sleep and 4.7 ±7.9 days of unintentionally falling asleep during the preceding month). Distress intolerance partially accounted for the associations of inadequate sleep and unintentionally falling asleep, but not sleep duration, with urban stress and more days of poor mental and physical health. Many homeless individuals endure sleep problems. Given the connections between sleep and morbidity and mortality, results further support the need for more attention directed toward facilitating improvements in sleep quality to improve the quality of life of homeless adults, potentially including attention to improving distress tolerance skills.
The Application of Problem-Based Learning in Mechanical Engineering

Science.gov (United States)

Putra, Z. A.; Dewi, M.

2018-02-01

The course of Technology and Material Testing prepare students with the ability to do a variety of material testing in the study of mechanical engineering. Students find it difficult to understand the materials to make them unable to carry out the material testing in accordance with the purpose of study. This happens because they knowledge is not adequately supported by the competence to find and construct learning experience. In this study, quasy experiment research method with pre-post-test with control group design was used. The subjects of the study were students divided in two groups; control and experiment with twenty-two students in each group. Study result: their grades showed no difference in between the pre-test or post-test in control group, but the difference in grade existed between the pre-test and post-test in experiment group. Yet, there is no significant difference in the study result on both groups. The researcher recommend that it is necessary to develop Problem-Based Learning that suits need analysis on D3 Program for Mechanical Engineering Department at the State University of Padang, to ensure the compatibility between Model of Study and problems and need. This study aims to analyze how Problem-Based Learning effects on the course of Technology and Material Testing for the students of D3 Program of Mechanical Engineering of the State University of Padang.
Perm State University HPC-hardware and software services: capabilities for aircraft engine aeroacoustics problems solving

Science.gov (United States)

Demenev, A. G.

2018-02-01

The present work is devoted to analyze high-performance computing (HPC) infrastructure capabilities for aircraft engine aeroacoustics problems solving at Perm State University. We explore here the ability to develop new computational aeroacoustics methods/solvers for computer-aided engineering (CAE) systems to handle complicated industrial problems of engine noise prediction. Leading aircraft engine engineering company, including “UEC-Aviadvigatel” JSC (our industrial partners in Perm, Russia), require that methods/solvers to optimize geometry of aircraft engine for fan noise reduction. We analysed Perm State University HPC-hardware resources and software services to use efficiently. The performed results demonstrate that Perm State University HPC-infrastructure are mature enough to face out industrial-like problems of development CAE-system with HPC-method and CFD-solvers.

Health problems and stress in Information Technology and Business Process Outsourcing employees.

Science.gov (United States)

Padma, V; Anand, N N; Gurukul, S M G Swaminatha; Javid, S M A Syed Mohammed; Prasad, Arun; Arun, S

2015-04-01

Stress is high in software profession because of their nature of work, target, achievements, night shift, over work load. 1. To study the demographic profile of the employees. 2. To access the level of job stress and quality of life of the respondents. 3. To study in detail the health problems of the employees. All employees working in IT and BPO industry for more than two years were included into the study. A detailed questionnaire of around 1000 IT and BPO employees including their personal details, stress score by Holmes and Rahe to assess the level of stress and master health checkup profile were taken and the results were analysed. Around 56% had musculoskeletal symptoms. 22% had newly diagnosed hypertension,10% had diabetes, 36% had dyslipidemia, 54% had depression, anxiety and insomnia, 40% had obesity. The stress score was higher in employees who developed diabetes, hypertension and depression. Early diagnosis of stress induced health problems can be made out by stress scores, intense lifestyle modification, diet advice along with psychological counselling would reduce the incidence of health problems in IT sector and improve the quality of work force.
Engineering tolerance to industrially relevant stress factors in yeast cell factories.

Science.gov (United States)

Deparis, Quinten; Claes, Arne; Foulquié-Moreno, Maria R; Thevelein, Johan M

2017-06-01

The main focus in development of yeast cell factories has generally been on establishing optimal activity of heterologous pathways and further metabolic engineering of the host strain to maximize product yield and titer. Adequate stress tolerance of the host strain has turned out to be another major challenge for obtaining economically viable performance in industrial production. Although general robustness is a universal requirement for industrial microorganisms, production of novel compounds using artificial metabolic pathways presents additional challenges. Many of the bio-based compounds desirable for production by cell factories are highly toxic to the host cells in the titers required for economic viability. Artificial metabolic pathways also turn out to be much more sensitive to stress factors than endogenous pathways, likely because regulation of the latter has been optimized in evolution in myriads of environmental conditions. We discuss different environmental and metabolic stress factors with high relevance for industrial utilization of yeast cell factories and the experimental approaches used to engineer higher stress tolerance. Improving stress tolerance in a predictable manner in yeast cell factories should facilitate their widespread utilization in the bio-based economy and extend the range of products successfully produced in large scale in a sustainable and economically profitable way. © FEMS 2017.
Engineering tolerance to industrially relevant stress factors in yeast cell factories

Science.gov (United States)

Deparis, Quinten; Claes, Arne; Foulquié-Moreno, Maria R.

2017-01-01

Abstract The main focus in development of yeast cell factories has generally been on establishing optimal activity of heterologous pathways and further metabolic engineering of the host strain to maximize product yield and titer. Adequate stress tolerance of the host strain has turned out to be another major challenge for obtaining economically viable performance in industrial production. Although general robustness is a universal requirement for industrial microorganisms, production of novel compounds using artificial metabolic pathways presents additional challenges. Many of the bio-based compounds desirable for production by cell factories are highly toxic to the host cells in the titers required for economic viability. Artificial metabolic pathways also turn out to be much more sensitive to stress factors than endogenous pathways, likely because regulation of the latter has been optimized in evolution in myriads of environmental conditions. We discuss different environmental and metabolic stress factors with high relevance for industrial utilization of yeast cell factories and the experimental approaches used to engineer higher stress tolerance. Improving stress tolerance in a predictable manner in yeast cell factories should facilitate their widespread utilization in the bio-based economy and extend the range of products successfully produced in large scale in a sustainable and economically profitable way. PMID:28586408
Class and Home Problems: Humidification, a True "Home" Problem for p. Chemical Engineer

Science.gov (United States)

Condoret, Jean-Stephane

2012-01-01

The problem of maintaining hygrothermal comfort in a house is addressed using the chemical engineer's toolbox. A simple dynamic modelling proved to give a good description of the humidification of the house in winter, using a domestic humidifier. Parameters of the model were identified from a simple experiment. Surprising results, especially…
Book of abstracts Chemical Engineering: IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists. Chemical engineering of nanomaterials. Energy- and resource-saving chemical-engineering processes and problems of their intensification. Processes and apparatuses of chemical engineering, chemical cybernetics. Ecological problems of chemical engineering and related fields

International Nuclear Information System (INIS)

Zakhodyaeva, Yu.A.; Belova, V.V.

2012-01-01

In the given volume of abstracts of the IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists (Moscow, March 18-23, 2012) there are the abstracts of the reports concerning chemical engineering of nanomaterials, energy- and resource-saving chemical-engineering processes, processes and apparatuses of chemical engineering, chemical cybernetics, ecological problems of chemical engineering and related fields. The abstracts deal with state-of-the-art and future development of theoretical and experimental investigations as well as with experience in practical realization of development works in the field of chemical engineering and relative areas [ru
Using Conjugate Gradient Network to Classify Stress Level of Patients.

Directory of Open Access Journals (Sweden)

Er. S. Pawar

2013-02-01

Full Text Available Diagnosis of stress is important because it can cause many diseases e.g., heart disease, headache, migraine, sleep problems, irritability etc. Diagnosis of stress in patients often involves acquisition of biological signals for example heart rate, electrocardiogram (ECG, electromyography signals (EMG etc. Stress diagnosis using biomedical signals is difficult and since the biomedical signals are too complex to generate any rule an experienced person or expert is needed to determine stress levels. Also, it is not feasible to use all the features that are available or possible to extract from the signal. So, relevant features should be chosen from the extracted features that are capable to diagnose stress. Electronics devices are increasingly being seen in the field of medicine for diagnosis, therapy, checking of stress levels etc. The research and development work of medical electronics engineers leads to the manufacturing of sophisticated diagnostic medical equipment needed to ensure good health care. Biomedical engineering combines the design and problem solving skills of engineering with medical and biological sciences to improve health care diagnosis and treatment.
Parenting Stress Related to Behavioral Problems and Disease Severity in Children with Problematic Severe Asthma.

Science.gov (United States)

Verkleij, Marieke; van de Griendt, Erik-Jonas; Colland, Vivian; van Loey, Nancy; Beelen, Anita; Geenen, Rinie

2015-09-01

Our study examined parenting stress and its association with behavioral problems and disease severity in children with problematic severe asthma. Research participants were 93 children (mean age 13.4 ± 2.7 years) and their parents (86 mothers, 59 fathers). As compared to reference groups analyzed in previous research, scores on the Parenting Stress Index in mothers and fathers of the children with problematic severe asthma were low. Higher parenting stress was associated with higher levels of internalizing and externalizing behavioral problems in children (Child Behavior Checklist). Higher parenting stress in mothers was also associated with higher airway inflammation (FeNO). Thus, although parenting stress was suggested to be low in this group, higher parenting stress, especially in the mother, is associated with more airway inflammation and greater child behavioral problems. This indicates the importance of focusing care in this group on all possible sources of problems, i.e., disease exacerbations and behavioral problems in the child as well as parenting stress.
The Co-Development of Parenting Stress and Childhood Internalizing and Externalizing Problems

OpenAIRE

Stone, Lisanne L.; Mares, Suzanne H. W.; Otten, Roy; Engels, Rutger C. M. E.; Janssens, Jan M. A. M.

2015-01-01

Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems is related to the development of parenting stress in children aged 4-9. Mothers of 1582 children participated in three one-year interval data waves. Internalizing and externalizing problems as wel...
Investigating and Developing Engineering Students' Mathematical Modelling and Problem-Solving Skills

Science.gov (United States)

Wedelin, Dag; Adawi, Tom; Jahan, Tabassum; Andersson, Sven

2015-01-01

How do engineering students approach mathematical modelling problems and how can they learn to deal with such problems? In the context of a course in mathematical modelling and problem solving, and using a qualitative case study approach, we found that the students had little prior experience of mathematical modelling. They were also inexperienced…
Excel 2013 for engineering statistics a guide to solving practical problems

CERN Document Server

Quirk, Thomas J

2015-01-01

This is the first book to show the capabilities of Microsoft Excel to teach engineering statistics effectively. It is a step-by-step exercise-driven guide for students and practitioners who need to master Excel to solve practical engineering problems. If understanding statistics isn’t your strongest suit, you are not especially mathematically-inclined, or if you are wary of computers, this is the right book for you. Excel, a widely available computer program for students and managers, is also an effective teaching and learning tool for quantitative analyses in engineering courses. Its powerful computational ability and graphical functions make learning statistics much easier than in years past. However, Excel 2013 for Engineering Statistics: A Guide to Solving Practical Problems is the first book to capitalize on these improvements by teaching students and managers how to apply Excel to statistical techniques necessary in their courses and work. Each chapter explains statistical formulas and directs...
Do causes of stress differ in their association with problem drinking by sex in Korean adolescents?

Science.gov (United States)

Choi, Jae-Woo; Park, Eun-Cheol; Kim, Jae-Hyun; Park, So-Hee

2017-01-01

Previous studies have focused mainly on whether stress causes present drinking or excessive drinking. However, few studies have been conducted on the relationship between stress and problem drinking in adolescents. The objective of this study was to examine the stress level and the cause of stress related to problem drinking behavior according to sex among Korean youth. Data for this study were pooled from cross-sectional data collected annually from 2007 through 2012 from the Korea Youth Risk Behavior Web-based Survey. A representative sample of 442,113 students from 800 randomly selected middle and high schools in Korea were included. Multiple logistic regression models were used in the analysis. Both male and female students with extremely high stress were more likely to engage in problem drinking than were students with no stress (odds ratios [OR], 1.73 in males and 1.41 in females). The major causes of stress in male students that were associated with problem drinking were conflict with a teacher, trouble with parents, and peer relationships (ORs, 2.47, 1.72, and 1.71, respectively), whereas there are no statistically significant association between causes of stress and problem drinking among female students. Considering stress level, Male students with extremely high stress level were associated with problem drinking regardless of causes of stress, while Female students who felt extremely high levels of stress were more likely to engage in problem drinking due to stress from a conflict with parents, peer relationships, appearance, and financial difficulty (ORs, 1.53, 1.53, 1.46, and 1.47, respectively). Adolescents who engage in problem drinking may be affected by different causes of stress according to sex. Thus, appropriate approaches that reflect sex differences will be helpful to alleviate problem drinking in adolescents and educational authorities need to arrange more effective education program for drinking given positive associations between drinking
Using Ontological Engineering to Overcome AI-ED Problems: Contribution, Impact and Perspectives

Science.gov (United States)

Mizoguchi, Riichiro; Bourdeau, Jacqueline

2016-01-01

This article reflects on the ontology engineering methodology discussed by the paper entitled "Using Ontological Engineering to Overcome AI-ED Problems" published in this journal in 2000. We discuss the achievements obtained in the last 10 years, the impact of our work as well as recent trends and perspectives in ontology engineering for…
Engineering problems of tandem-mirror reactors

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Boghosian, B.M.

1981-01-01

We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper
Teaching Mathematics to Civil Engineers

Science.gov (United States)

Sharp, J. J.; Moore, E.

1977-01-01

This paper outlines a technique for teaching a rigorous course in calculus and differential equations which stresses applicability of the mathematics to problems in civil engineering. The method involves integration of subject matter and team teaching. (SD)
Parenting Stress and Emotional/Behavioral Problems in Adolescents with Primary Headache.

Science.gov (United States)

Operto, Francesca Felicia; Craig, Francesco; Peschechera, Antonia; Mazza, Roberta; Lecce, Paola Alessandra; Margari, Lucia

2017-01-01

Primary headache is a frequent and disabling disorder, common among children and adolescents, and it is a painful syndrome often accompanied by functional impairment and associated with emotional and behavior problems. The aim of this study was to investigate parenting stress and emotional/behavioral problems in adolescents affected by primary headache compared with healthy adolescents. The study population consisted of 35 adolescents and a control group of 23 healthy subjects. The assessment included the administration of clinical standardized scales such as Parent Stress Index-Short Form, Pediatric Migraine Disability Assessment Score Questionnaire, and Child Behavior Checklist (CBCL). Headache group and control group did not differ in terms of parenting stress ( p = 0.29). On the contrary, headache group showed more internalizing problems ( p = 0.023), affective problems ( p = 0.01), anxious ( p = 0.001), and somatic complaints ( p headache group. The findings emphasize the need for expanded intervention in the clinical treatment of pediatric headache, a treatment that may also include the family members. Further research is needed.
Introducing future engineers to sustainable ecology problems: a case study

Science.gov (United States)

Filipkowski, A.

2011-12-01

The problem of Earth environmental destruction by human activities is becoming dangerous. Engineers responsible for the production of any goods should be well aware of the negative influence of their activities on the state of the planet. This is why the understanding of ecological problems is essential for people responsible for production and industrial design. The energy, which they consume, is increasing the greenhouse effect and the waste poisons the environment. So far, most courses on ecology are offered to specialists in environmental engineering. These courses are filled with many details. The Warsaw Academy of Computer Science, Management and Administration teaches students in the direction of management and production engineering. Upon completion, the students receive the degree of 'engineer'. Their future work will mainly concern management of different types of industrial enterprises and they will be responsible for organising it in such a way as to avoid a dangerous contribution to environmental pollution and climate change. This is why it was decided to introduce a new course entitled 'Principles of Ecology and Environmental Management'. This course is quite broad, concerning almost all technical, law and organisational aspects of the problem. The presentation is made in a spectacular way, aiming to convince students that their future activity must be environmentally friendly. It contains information about international activities in ecology, legal aspects concerning pollution, technical and information methods of monitoring and, finally, the description of 'green' solutions. Altogether, 27 hours of lectures and 15 hours of discussions and students' presentations complete the course. Details of this course are described in this paper.
Managing Stress and Maintaining Well-Being: Social Support, Problem-Focused Coping, and Avoidant Coping

Science.gov (United States)

Chao, Ruth Chu-Lien

2011-01-01

This study tested a model that links stress, social support, problem-focused coping, and well-being. First, it looks at how high support significantly moderated the association between stress and well-being. Next, the students' problem-focused coping was seen as mediating this moderated association. Finally, a 3-way interaction of stress, social…
Engineering computation of structures the finite element method

CERN Document Server

Neto, Maria Augusta; Roseiro, Luis; Cirne, José; Leal, Rogério

2015-01-01

This book presents theories and the main useful techniques of the Finite Element Method (FEM), with an introduction to FEM and many case studies of its use in engineering practice. It supports engineers and students to solve primarily linear problems in mechanical engineering, with a main focus on static and dynamic structural problems. Readers of this text are encouraged to discover the proper relationship between theory and practice, within the finite element method: Practice without theory is blind, but theory without practice is sterile. Beginning with elasticity basic concepts and the classical theories of stressed materials, the work goes on to apply the relationship between forces, displacements, stresses and strains on the process of modeling, simulating and designing engineered technical systems. Chapters discuss the finite element equations for static, eigenvalue analysis, as well as transient analyses. Students and practitioners using commercial FEM software will find this book very helpful. It us...
A method of solution of the elastic-plastic thermal stress problem

International Nuclear Information System (INIS)

Rafalski, P.

1975-01-01

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

Science.gov (United States)

Ohishi, Toshihiro

The purpose of this paper is to clarify the features of whistleblowing by considering the arguments about whistleblowing in engineering ethics. First, I analyze the concept of ‘whistleblowing’ by defining the word as clearly as possible. Second, I examine the standard justification theory of whistleblowing by showing the problems of the theory. Finally, I analyze the dilemma about whistleblowing by revealing a prospective whistleblower‧s struggle to choose moral value or non-moral value.

The stress distribution in shell bodies and wings as an equilibrium problem

Science.gov (United States)

Wagner, H

1937-01-01

This report treats the stress distribution in shell-shaped airplane components (fuselage, wings) as an equilibrium problem; it includes both cylindrical and non-cylindrical shells. In particular, it treats the stress distribution at the point of stress application and at cut-out points.
Basic stress analysis

CERN Document Server

Iremonger, M J

1982-01-01

BASIC Stress Analysis aims to help students to become proficient at BASIC programming by actually using it in an important engineering subject. It also enables the student to use computing as a means of learning stress analysis because writing a program is analogous to teaching-it is necessary to understand the subject matter. The book begins by introducing the BASIC approach and the concept of stress analysis at first- and second-year undergraduate level. Subsequent chapters contain a summary of relevant theory, worked examples containing computer programs, and a set of problems. Topics c
Job stress models, depressive disorders and work performance of engineers in microelectronics industry.

Science.gov (United States)

Chen, Sung-Wei; Wang, Po-Chuan; Hsin, Ping-Lung; Oates, Anthony; Sun, I-Wen; Liu, Shen-Ing

2011-01-01

Microelectronic engineers are considered valuable human capital contributing significantly toward economic development, but they may encounter stressful work conditions in the context of a globalized industry. The study aims at identifying risk factors of depressive disorders primarily based on job stress models, the Demand-Control-Support and Effort-Reward Imbalance models, and at evaluating whether depressive disorders impair work performance in microelectronics engineers in Taiwan. The case-control study was conducted among 678 microelectronics engineers, 452 controls and 226 cases with depressive disorders which were defined by a score 17 or more on the Beck Depression Inventory and a psychiatrist's diagnosis. The self-administered questionnaires included the Job Content Questionnaire, Effort-Reward Imbalance Questionnaire, demography, psychosocial factors, health behaviors and work performance. Hierarchical logistic regression was applied to identify risk factors of depressive disorders. Multivariate linear regressions were used to determine factors affecting work performance. By hierarchical logistic regression, risk factors of depressive disorders are high demands, low work social support, high effort/reward ratio and low frequency of physical exercise. Combining the two job stress models may have better predictive power for depressive disorders than adopting either model alone. Three multivariate linear regressions provide similar results indicating that depressive disorders are associated with impaired work performance in terms of absence, role limitation and social functioning limitation. The results may provide insight into the applicability of job stress models in a globalized high-tech industry considerably focused in non-Western countries, and the design of workplace preventive strategies for depressive disorders in Asian electronics engineering population.
Stirling engines for biomass – what is the problem?

DEFF Research Database (Denmark)

Carlsen, Henrik

2005-01-01

The External combustion of the Stirling engine makes it very attractive for small-scale Combined Heat and Power (CHP) plants using bio-fuels. Especially wood chips are an attractive fuel because of the high melting point and the low content of ash. Unfortunately, it is more complicated than...... expected to use bio-fuels for a Stirling engine. The high temperature in the hot heat exchanger transferring heat from the combustion to the Stirling engine combined with the low heating value of the fuel reduce the obtainable efficiency of the plant. The limitations of the combustion temperature in order...... to avoid melted ash in the combustion chamber decrease the obtainable efficiency even further. If a Stirling engine, which has an efficiency of 28,5% using natural gas, is converted into utilization of bio-fuel, the efficiency will decrease to 17,5%. Another problem for utilization of bio-fuels in Stirling...
Testing foreign language impact on engineering students' scientific problem-solving performance

Science.gov (United States)

Tatzl, Dietmar; Messnarz, Bernd

2013-12-01

This article investigates the influence of English as the examination language on the solution of physics and science problems by non-native speakers in tertiary engineering education. For that purpose, a statistically significant total number of 96 students in four year groups from freshman to senior level participated in a testing experiment in the Degree Programme of Aviation at the FH JOANNEUM University of Applied Sciences, Graz, Austria. Half of each test group were given a set of 12 physics problems described in German, the other half received the same set of problems described in English. It was the goal to test linguistic reading comprehension necessary for scientific problem solving instead of physics knowledge as such. The results imply that written undergraduate English-medium engineering tests and examinations may not require additional examination time or language-specific aids for students who have reached university-entrance proficiency in English as a foreign language.
Mechanical engineering problems in the TFTR neutral beam system

International Nuclear Information System (INIS)

Cannon, D.D.; Bryant, E.H.; Johnson, R.L.; Kim, J.; Queen, C.C.; Schilling, G.

1975-01-01

A conceptual design of a prototype beam line for the TFTR Neutral Beam System has been developed. The basic components have been defined, cost estimates prepared, and the necessary development programs identified. Four major mechanical engineering problems, potential solutions and the required development programs are discussed
Stress cardiomyopathy: Is it limited to Takotsubo syndrome? Problems of definition.

Science.gov (United States)

Sarapultsev, Petr A; Sarapultsev, Alexey P

2016-10-15

In 2006, Takotsubo syndrome (TTC) was described as a distinct type of stress-induced cardiomyopathy (stress cardiomyopathy). However, when thinking about Takotsubo cardiomyopathy from the viewpoints of the AHA and ESC classifications, 2 possible problems may arise. The first potential problem is that a forecast of disease outcome is lacking in the ESC classification, whereas the AHA only states that 'outcome is favorable with appropriate medical therapy'. However, based on the literature data, one can make a general conclusion that occurrence of myocardial lesions in TTC (i.e., myocardial fibrosis and contraction-band necrosis) causes the same effects as in other diseases with similar levels of myocardial damage and should not be considered to have a lesser impact on mortality. To summarise, TTC can cause not only severe complications such as pulmonary oedema, cardiogenic shock, and dangerous ventricular arrhythmias, but also damage to the myocardium, which can result in the development of potentially fatal conditions even after the disappearance of LV apical ballooning. The second potential problem arises from the definition of TTC as a stress cardiomyopathy in the AHA classification. In fact, the main factors leading to TTC are stress and microvascular anginas, since, as has been already discussed, coronary spasm can cause myocardium stunning, resulting in persistent apical ballooning. Thus, based on this review, 3 distinct types of stress cardiomyopathies exist (variant angina, microvascular angina, and TTC), with poor prognosis. Adding these diseases to the classification of cardiomyopathies will facilitate diagnosis and preventive prolonged treatment, which should include intensive anti-stress therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
A Case Study: Problem-Based Learning for Civil Engineering Students in Transportation Courses

Science.gov (United States)

Ahern, A. A.

2010-01-01

This paper describes two case studies where problem-based learning (PBL) has been introduced to undergraduate civil engineering students in University College Dublin. PBL has recently been put in place in the penultimate and final year transport engineering classes in the civil engineering degree in University College Dublin. In this case study,…
Mediator or moderator? The role of mindfulness in the association between child behavior problems and parental stress.

Science.gov (United States)

Chan, Tim Oi; Lam, Shui-Fong

2017-11-01

Raising a child with intellectual disability (ID) may be stressful for parents. Previous studies have suggested the mediating role of mindfulness in the association between child behavior problems and parental stress. The present study examined whether this mediating role is a result of parents' self-report bias. It also explored whether mindfulness has a moderating role instead when child behavior problems are reported by teachers. In a questionnaire survey, 271 Chinese parents of children with ID in 6 Hong Kong special schools reported their levels of stress and mindfulness, as well as their children's behavior problems. The latter was also reported by teachers. When child behavior problems were reported by parents, parental mindfulness was a mediator between child behavior problems and parental stress. In contrast, when child behavior problems were reported by teachers, parental mindfulness was a moderator between child behavior problems and parental stress. The mediation role of mindfulness maybe an artifact of measurement. The findings provide an encouraging message that parenting a child with ID and behavior problems does not necessarily mean more stress among all parents. Parents with a high level of mindfulness may experience less stress than those with a low level of mindfulness. Parents of children with intellectual disability (ID) tend to report high psychological stress. Previous self-report studies have identified mindfulness as a mediator in the association between child behavior problems and parental stress. The present study differs from previous studies by including third-party's reports. It has contributed to the existing body of knowledge in two respects. First, it examined whether the mediation effect resulted from parent self-report bias. Second, it tested an alternative hypothesis of the moderation effect by using teachers' reports to measure child behavior problems. The results showed that when child behavior problems were measured by parents
Modelling of composition and stress profiles in low temperature surface engineered stainless steel

DEFF Research Database (Denmark)

Jespersen, Freja Nygaard; Hattel, Jesper Henri; Somers, Marcel A. J.

2015-01-01

temperature, time and gas composition is a prerequisite for targeted process optimization. A realistic model to simulate the developing case has to take the following influences on composition and stress into account: - a concentration dependent diffusion coefficient - trapping of nitrogen by chromium atoms...... stresses are introduced in the developing case, arising from the volume expansion that accompanies the dissolution of high interstitial contents in expanded austenite. Modelling of the composition and stress profiles developing during low temperature surface engineering from the processing parameters...... - the effect of residual stress on diffusive flux - the effect of residual stress on solubility of interstitials - plastic accommodation of residual stress. The effect of all these contributions on composition and stress profiles will be addressed....
Target system materials and engineering problems

International Nuclear Information System (INIS)

Fischer, W.E.

1989-01-01

This paper discusses the common problems of target design. As a model for the discussion, the author considers a spallation source which is fed by a high power proton beam of the order of one megawatt. The materials used for the target station and particularly for the spallation target itself depend on whether the source is built for pulsed, modulated or continuous operation. The difference of materials used is mainly determined by the neutronics considerations. Depending on the choice of materials for the target systems, the characters of material problems met, are of somewhat different nature. It is recognized that for each target version quite specific difficulties have to be overcome. On the other hand, there is a whole set of problems which is common to all target versions. These are: heat load in region of proton beam interactions; thermal stress and cycling; and radiation damage. It is shown that solutions to the whole package of problems up to a beam power of 0 (1MW) have been found. The whole effort concentrates onto the region of the first few centimeters of beam penetration. Two solutions have been proposed: (1) Keep the power of proton beam limited and produce neutrons elsewhere in the target. and (2) Dilute the power by moving mechanically the target and the window. 8 refs., 11 figs
Long-Term Effectiveness of Stress Management at Work: Effects of the Changes in Perceived Stress Reactivity on Mental Health and Sleep Problems Seven Years Later.

Science.gov (United States)

Herr, Raphael M; Barrech, Amira; Riedel, Natalie; Gündel, Harald; Angerer, Peter; Li, Jian

2018-02-03

The reduction of stress reactivity resulting from stress management interventions prevents disorders and improves mental health, however, its long-term sustainability has been little examined. The objective of this study was, therefore, to determine the effectiveness of a stress management intervention, designed to improve stress reactivity, for mental health and sleep problems seven years later, using longitudinal data from 101 male industrial workers. Linear regressions estimated the adjusted effects of the changes in stress reactivity in general as well as in its six subdimensions (work overload, social conflict, social stress, failure at work, and anticipatory and prolonged reactivity) on depression, anxiety, and sleep problems seven years later. The improvement of the prolonged reactivity had positive effects on depression, anxiety, and sleep problems (unstandardized regression coefficients [ Bs ] ≥ 0.35, all p -values ≤ 0.01). Depression and sleep problems were further improved by a reduction of the reactivity to social conflicts ( Bs ≥ 0.29, p -values stress reactivity resulting from a work stress intervention was effective and generally long-lasting in preventing mental health and sleep problems. The reduction of the prolonged reactivity seems of particular importance and efficient in inhibiting negative stress manifestations.
Molecular engineering problems in heat and mass transfer

International Nuclear Information System (INIS)

Kotake, S.

1991-01-01

As for developing, manufacturing and applying new materials of advanced functions such as high-performance devices and high-temperature materials, fundamental understanding of the phenomena from the standpoint of molecular and atomic levels has been required. In these problems, the processes of heat and mass transfer play an important role, being one of the rate-controlling factors. But the energy levels associated with heat and mass transfer are of the orders much less than those of chemical reaction, and it is not easy to understand the thermal problems on the molecular and atomic basis. This paper views the processes of heat and mass transfer from the dynamical motions of atom and molecule for thermal engineering problems. Especially, problems are considered of heat conduction in fine-ceramics, sintered materials of high heat conductivity or high heat-insulation, phase change of condensation in vapor deposition processes such as CVD and PVD, and radiation in laser processing
NON-INVASIVE INVERSE PROBLEM IN CIVIL ENGINEERING

Directory of Open Access Journals (Sweden)

Jan Havelka

2017-11-01

Full Text Available In this contribution we focus on recovery of spatial distribution of material parameters utilizing only non-invasive boundary measurements. Such methods has gained its importance as imaging techniques in medicine, geophysics or archaeology. We apply similar principles for non-stationary heat transfer in civil engineering. In oppose to standard technique which rely on external loading devices, we assume the natural fluctuation of temperature throughout day and night can provide sufficient information to recover the underlying material parameters. The inverse problem was solved by a modified regularised Gauss-Newton iterative scheme and the underlying forward problem is solved with a finite element space-time discretisation. We show a successful reconstruction of material parameters on a synthetic example with real measurements. The virtual experiment also reveals the insensitivity to practical precision of sensor measurements.
Problem solving in nuclear engineering using supercomputers

International Nuclear Information System (INIS)

Schmidt, F.; Scheuermann, W.; Schatz, A.

1987-01-01

The availability of supercomputers enables the engineer to formulate new strategies for problem solving. One such strategy is the Integrated Planning and Simulation System (IPSS). With the integrated systems, simulation models with greater consistency and good agreement with actual plant data can be effectively realized. In the present work some of the basic ideas of IPSS are described as well as some of the conditions necessary to build such systems. Hardware and software characteristics as realized are outlined. (orig.) [de
Parenting stress and child behaviour problems among parents with intellectual disabilities: the buffering role of resources.

Science.gov (United States)

Meppelder, M; Hodes, M; Kef, S; Schuengel, C

2015-07-01

Parents with intellectual disabilities (ID) are at risk for high levels of parenting stress. The present study evaluated resources, including parental adaptive functioning, financial resources and access to a support network, as moderators of the association between child behaviour problems and parenting stress. A total of 134 parents with ID and their children (ages 1-7 years) were recruited from 10 Dutch care organisations. Questionnaires were administered to the parents to obtain information on parenting stress in the parent and child domain, financial resources and their support network. Teachers and care workers reported on child behaviour problems and parental adaptive functioning, respectively. Parents experienced more stress with regard to their children than towards their own functioning and situation. Parenting stress was less in parents who were not experiencing financial hardship. Child behaviour problems were associated with high child-related parenting stress, not parent-related parenting stress. Large support networks decreased the association between child behaviour problems and child-related parenting stress. Financial resources did not significantly moderate the association. Parenting stress among parents with ID is focused on problems with the child, especially when little social support is available. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.
Child Behavior Problems, Teacher Executive Functions, and Teacher Stress in Head Start Classrooms.

Science.gov (United States)

Friedman-Krauss, Allison H; Raver, C Cybele; Neuspiel, Juliana M; Kinsel, John

2014-01-01

The current article explores the relationship between teachers' perceptions of child behavior problems and preschool teacher job stress, as well as the possibility that teachers' executive functions moderate this relationship. Data came from 69 preschool teachers in 31 early childhood classrooms in 4 Head Start centers and were collected using Web-based surveys and Web-based direct assessment tasks. Multilevel models revealed that higher levels of teachers' perceptions of child behavior problems were associated with higher levels of teacher job stress and that higher teacher executive function skills were related to lower job stress. However, findings did not yield evidence for teacher executive functions as a statistical moderator. Many early childhood teachers do not receive sufficient training for handling children's challenging behaviors. Child behavior problems increase a teacher's workload and consequently may contribute to feelings of stress. However, teachers' executive function abilities may enable them to use effective, cognitive-based behavior management and instructional strategies during interactions with students, which may reduce stress. Providing teachers with training on managing challenging behaviors and enhancing executive functions may reduce their stress and facilitate their use of effective classroom practices, which is important for children's school readiness skills and teachers' health.
Problem Solving Method Based on E-Learning System for Engineering Education

Science.gov (United States)

Khazaal, Hasan F.

2015-01-01

Encouraging engineering students to handle advanced technology with multimedia, as well as motivate them to have the skills of solving the problem, are the missions of the teacher in preparing students for a modern professional career. This research proposes a scenario of problem solving in basic electrical circuits based on an e-learning system…
Transactional relations between caregiving stress, executive functioning, and problem behavior from early childhood to early adolescence

Science.gov (United States)

LaGasse, Linda L.; Conradt, Elisabeth; Karalunas, Sarah L.; Dansereau, Lynne M.; Butner, Jonathan E.; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles R.; Whitaker, Toni M.; Lester, Barry M.

2016-01-01

Developmental psychopathologists face the difficult task of identifying the environmental conditions that may contribute to early childhood behavior problems. Highly stressed caregivers can exacerbate behavior problems, while children with behavior problems may make parenting more difficult and increase caregiver stress. Unknown is: (1) how these transactions originate, (2) whether they persist over time to contribute to the development of problem behavior and (3) what role resilience factors, such as child executive functioning, may play in mitigating the development of problem behavior. In the present study, transactional relations between caregiving stress, executive functioning, and behavior problems were examined in a sample of 1,388 children with prenatal drug exposures at three developmental time points: early childhood (birth-age 5), middle childhood (ages 6 to 9), and early adolescence (ages 10 to 13). Transactional relations differed between caregiving stress and internalizing versus externalizing behavior. Targeting executive functioning in evidence-based interventions for children with prenatal substance exposure who present with internalizing problems and treating caregiving psychopathology, depression, and parenting stress in early childhood may be particularly important for children presenting with internalizing behavior. PMID:27427803
Review on study of multi-physics in environment engineering

International Nuclear Information System (INIS)

Liu Shanli; Zhao Jian; Sheng Jinchang

2006-01-01

This paper analyzes some problems on multi-field coupling ones between seepage mechanics and other physical and chemical processes (such as temperature field. stress field, solute transport. chemical action and so on) in environment engineering, it explains the research theory of multi-field coupling, it summarizes the abroad and domestic research about the model of multi-field problem and finally it looks into the future of research tendency in environment engineering. (authors)

Financial Stress, Parental Depressive Symptoms, Parenting Practices, and Children's Externalizing Problem Behaviors: Underlying Processes

Science.gov (United States)

Lee, Chih-Yuan Steven; Lee, Jaerim; August, Gerald J.

2011-01-01

This study examined the relationships among financial stress encountered by families, parents' social support, parental depressive symptoms, parenting practices, and children's externalizing problem behaviors to advance our understanding of the processes by which family financial stress is associated with children's problem behaviors. We also…
Impacts of autistic behaviors, emotional and behavioral problems on parenting stress in caregivers of children with autism.

Science.gov (United States)

Huang, Chien-Yu; Yen, Hsui-Chen; Tseng, Mei-Hui; Tung, Li-Chen; Chen, Ying-Dar; Chen, Kuan-Lin

2014-06-01

This study examined the effects of autistic behaviors and individual emotional and behavioral problems on parenting stress in caregivers of children with autism. Caregivers were interviewed with the Childhood Autism Rating Scale and completed the Strength and Difficulties Questionnaire and the Parenting Stress Index Short Form. Results revealed that caregivers of children with mild/moderate autistic behavior problems perceived lower parenting stress than did those of children with no or severe problems. In addition, prosocial behaviors and conduct problems respectively predicted stress in the parent-child relationship and child-related stress. The findings can provide guidance in evaluations and interventions with a focus on mitigating parenting stress in caregivers of children with autism.
Child/Adolescent's ADHD and Parenting Stress: The Mediating Role of Family Impact and Conduct Problems.

Science.gov (United States)

Muñoz-Silva, Alicia; Lago-Urbano, Rocio; Sanchez-Garcia, Manuel; Carmona-Márquez, José

2017-01-01

Objective: The demands of parenting are usually associated with some stress, and elevated levels of stress may affect the parent-child relationships and parenting practices. This is especially the case of families where children have special needs conditions or disorders, like Attention Deficit Hyperactivity Disorder (ADHD). Method: This study examined parenting stress among mothers of children and adolescents with ADHD. The sample comprised 126 mothers of girls (36; 29%) and boys (90; 71%) aged 6-17 years old. Results: Mothers reported their own stress levels as well as the children and adolescents' variables (severity of their ADHD symptoms, conduct, and emotional problems) and family-contextual variables (negative impact on family's social life, impact on couple relationship, and perceived social support). Hierarchical multiple regression showed that (a) negative impact on social life and conduct problems were the strongest predictors of mother's stress. Bootstrap mediation analyses revealed that (b) the association between child and adolescent's ADHD and parenting stress was mediated by children's conduct problems and by negative impact on family's social life, and not by children's emotional problems nor by mother's perceived social support. The mediation analysis also suggested (c) a pathway from child/adolescent's ADHD through children's conduct problems and then through their negative impact on family's social life to mother's parenting stress. Conclusion: These results suggest that both child/adolescent's and family factors should be considered in the designing of interventions for reducing parenting stress in families of children and adolescents with ADHD.
Predicting maternal parenting stress in middle childhood: the roles of child intellectual status, behaviour problems and social skills.

Science.gov (United States)

Neece, C; Baker, B

2008-12-01

Parents of children with intellectual disabilities (ID) typically report elevated levels of parenting stress, and child behaviour problems are a strong predictor of heightened parenting stress. Interestingly, few studies have examined child characteristics beyond behaviour problems that may also contribute to parenting stress. The present longitudinal study examined the contribution of child social skills to maternal parenting stress across middle childhood, as well as the direction of the relationship between child social skills and parenting stress. Families of children with ID (n = 74) or typical development (TD) (n = 115) participated over a 2-year period. Maternal parenting stress, child behaviour problems and child social skills were assessed at child ages six and eight. Child social skills accounted for unique variance in maternal parenting stress above and beyond child intellectual status and child behaviour problems. As the children matured, there was a significant interaction between child social skills and behaviour problems in predicting parenting stress. With respect to the direction of these effects, a cross-lagged panel analysis indicated that early parenting stress contributed to later social skills difficulties for children, but the path from children's early social skills to later parenting stress was not supported, once child behaviour problems and intellectual status were accounted for. When examining parenting stress, child social skills are an important variable to consider, especially in the context of child behaviour problems. Early parenting stress predicted child social skills difficulties over time, highlighting parenting stress as a key target for intervention.
The Bree problem with different yield stresses on-load and off-load and application to creep ratcheting

International Nuclear Information System (INIS)

Bradford, R.A.W.; Ure, J.; Chen, H.F.

2014-01-01

The ratchet boundaries and ratchet strains are derived for the Bree problem and an elastic-perfectly plastic material with different yield stresses on-load and off-load. The Bree problem consists of a constant uniaxial primary membrane stress and a cycling thermal bending stress. The ratchet problem with differing yield stresses is also solved for a modified loading in which both the primary membrane and thermal bending stresses cycle in-phase. The analytic solutions for the ratchet boundaries are compared with the results of deploying the linear matching method (LMM) and excellent agreement is found. Whilst these results are of potential utility for purely elastic–plastic behaviour, since yield stresses will often differ at the two ends of the cycle, the solution is also proposed as a means of assessing creep ratcheting via a creep ductility exhaustion approach. -- Highlights: • The Bree problem is solved for differing yield stresses on and off load. • The modified Bree problem with cycling primary load is also solved. • These solutions can be applied to creep ratcheting using a pseudo-yield stress
Inverse problems in the design, modeling and testing of engineering systems

Science.gov (United States)

Alifanov, Oleg M.

1991-01-01

Formulations, classification, areas of application, and approaches to solving different inverse problems are considered for the design of structures, modeling, and experimental data processing. Problems in the practical implementation of theoretical-experimental methods based on solving inverse problems are analyzed in order to identify mathematical models of physical processes, aid in input data preparation for design parameter optimization, help in design parameter optimization itself, and to model experiments, large-scale tests, and real tests of engineering systems.
Gendered practices of constructing an engineering identity in a problem-based learning environment

DEFF Research Database (Denmark)

Du, Xiangyun

2006-01-01

of an engineering identity with masculinity and the culturally defined engineering competencies leads to different learning experiences for male and female students. The nature of hard-core engineering subjects, based on male interests, privileges men and acts as a barrier to women. The masculine culture......This article examines the learning experiences of engineering students of both genders in a problem-based and project-organized learning environment (PBL) at a Danish university. This study relates an amalgam of theories on learning and gender to the context of engineering education. Based on data...
Anxiety and posttraumatic stress symptom pathways to substance use problems among community women experiencing intimate partner violence.

Science.gov (United States)

Jaquier, Véronique; Flanagan, Julianne C; Sullivan, Tami P

2015-01-01

Although intimate partner violence (IPV) has demonstrated strong associations with anxiety and posttraumatic stress, these constructs have rarely been examined simultaneously in IPV research. Gaps in knowledge remain as to their differential associations to substance use problems among IPV-victimized women. A sample of 143 community women self-reported on their current IPV victimization, mental health and substance use problems. Hierarchical entry multiple regressions were used to test for the direct and indirect effects of psychological, physical, and sexual IPV to alcohol and drug problems through anxiety and posttraumatic stress. Higher anxiety symptom severity and higher physical IPV severity were associated with greater alcohol and drug problems. Higher posttraumatic stress symptom severity was associated with greater alcohol and drug problems. Mediation analyses indicated (i) significant indirect pathways of IPV types to alcohol problems through posttraumatic stress symptom severity controlling for anxiety symptom severity and (ii) significant indirect pathways of IPV types to drug problems through anxiety symptom severity controlling for posttraumatic stress symptom severity. In examining the indirect pathways of psychological, physical, and sexual IPV to substance use problems this study highlights that anxiety and posttraumatic stress symptom severity have unique effects on alcohol and drug problems among IPV-victimized women.
Child Behavior Problems, Teacher Executive Functions, and Teacher Stress in Head Start Classrooms

Science.gov (United States)

Friedman-Krauss, Allison H.; Raver, C. Cybele; Neuspiel, Juliana M.; Kinsel, John

2017-01-01

Research Findings The current article explores the relationship between teachers’ perceptions of child behavior problems and preschool teacher job stress, as well as the possibility that teachers’ executive functions moderate this relationship. Data came from 69 preschool teachers in 31 early childhood classrooms in 4 Head Start centers and were collected using Web-based surveys and Web-based direct assessment tasks. Multilevel models revealed that higher levels of teachers’ perceptions of child behavior problems were associated with higher levels of teacher job stress and that higher teacher executive function skills were related to lower job stress. However, findings did not yield evidence for teacher executive functions as a statistical moderator. Practice or Policy Many early childhood teachers do not receive sufficient training for handling children’s challenging behaviors. Child behavior problems increase a teacher’s workload and consequently may contribute to feelings of stress. However, teachers’ executive function abilities may enable them to use effective, cognitive-based behavior management and instructional strategies during interactions with students, which may reduce stress. Providing teachers with training on managing challenging behaviors and enhancing executive functions may reduce their stress and facilitate their use of effective classroom practices, which is important for children’s school readiness skills and teachers’ health. PMID:28596698
Bitumen/Water Emulsions as Fuels for High-Speed Ci Engines Preliminary Investigations

DEFF Research Database (Denmark)

Schramm, Jesper; Sigvardsen, R.; Forman, M.

2003-01-01

Mixtures of bitumen and water, are cheap fuel alternatives for combustion engines. There are, however, several problems that have to be solved before these fuels can be applied in high-speed diesel engines. These are: - emulsion break up due to high temperature or high shear stress in the injection...... system - high content of heavy metals - high emissions of particulate matter and PAH This investigation deals with the problem of separation due to high shear stress in the injection system. It is shown that the viscosity of the injected fuel can be used to estimate whether the emulsion has separated...
Role of hydrogen in stress corrosion cracking

International Nuclear Information System (INIS)

Louthan, M.R. Jr.

1975-01-01

Hydrogen embrittlement has been postulated as a cause of stress corrosion cracking in numerous alloy systems. Such an interrelationship is useful in design considerations because it permits the designer and working engineer to relate the literature from both fields to a potential environmental compatibility problem. The role of hydrogen in stress corrosion of high strength steels is described along with techniques for minimizing the susceptibility to hydrogen stress cracking. (U.S.)
Seminar Neutronika-2012. Neutron-physical problems of nuclear-power engineering. Program and abstracts

International Nuclear Information System (INIS)

2012-01-01

On October, 30 - November, 2 in State Scientific Center of the Russian Federation - Institute for Physics and Power Engineering named after A.I. Leypunsky a seminar Neutron-physical problems of nuclear power engineering - Neutronika-2012 took place. On the seminar the following problems were discussed: justification of neutron-physical characteristics of reactor facilities and innovation projects; constant support of neutron-physical calculations of nuclear power installations; numerical simulation during solving reactor physics problems; simulation of neutron-physical processes in reactor facilities by Monte Carlo method; development and verification of programs for reactor facilities neutron-physical calculations; algorithms and programs for solving nonstationary problems of neutron-physical calculation of nuclear reactors; analysis of integral and reactor experiments, experimental database; justification of nuclear and radiation safety of fuel cycle [ru
Stress and prevalence of hearing problems in the Swedish working population

Directory of Open Access Journals (Sweden)

Wallén Martin

2011-02-01

Full Text Available Abstract Background Current human and experimental studies are indicating an association between stress and hearing problems; however potential risk factors have not been established. Hearing problems are projected to become among the top ten disabilities according to the WHO in the near future. Therefore a better understanding of the relationships between stress and hearing is warranted. Here we describe the prevalence of two common hearing problems, i.e. hearing complaints and tinnitus, in relation to different work-and health-related stressors. Methods A total of 18,734 individuals were invited to participate in the study, out of which 9,756 (52% enrolled. Results The results demonstrate a clear and mostly linear relationship between higher prevalence of hearing problems (tinnitus or hearing loss or both and different stressors, e.g. occupational, poorer self-rated health, long-term illness, poorer sleep quality, and higher burnout scores. Conclusions The present study unambiguously demonstrates associations between hearing problems and various stressors that have not been previously described for the auditory system. These findings will open new avenues for future investigations.
Analysis of thermal stress of the piston during non-stationary heat flow in a turbocharged Diesel engine

Science.gov (United States)

Gustof, P.; Hornik, A.

2016-09-01

In the paper, numeric calculations of thermal stresses of the piston in a turbocharged Diesel engine in the initial phase of its work were carried out based on experimental studies and the data resulting from them. The calculations were made using a geometrical model of the piston in a five-cylinder turbocharged Diesel engine with a capacity of about 2300 cm3, with a direct fuel injection to the combustion chamber and a power rating of 85 kW. In order to determine the thermal stress, application of own mathematical models of the heat flow in characteristic surfaces of the piston was required to show real processes occurring on the surface of the analysed component. The calculations were performed using a Geostar COSMOS/M program module. A three-dimensional geometric model of the piston was created in this program based on a real component, in order to enable the calculations and analysis of thermal stresses during non-stationary heat flow. Modelling of the thermal stresses of the piston for the engine speed n=4250 min-1 and engine load λ=1.69 was carried out.
Child-Care Instability and Behavior Problems: Does Parenting Stress Mediate the Relationship?

Science.gov (United States)

Pilarz, Alejandra Ros; Hill, Heather D

2017-10-01

Child care instability is associated with more behavior problems in young children, but the mechanisms of this relationship are not well understood. Theoretically, this relationship is likely to emerge, at least in part, because care instability leads to increased parenting stress. Moreover, low socioeconomic status and single-mother families may be more vulnerable to the effects of instability. This study tested these hypotheses using data from the Fragile Families and Child Wellbeing study (n=1,675) and structural equation modeling. Three types of child care instability were examined: long-term instability, multiplicity, and needing to use back-up arrangements. Overall, findings showed little evidence that parenting stress mediated the associations between care instability and child behavior problems among the full sample. Among single-mother and low-income families, however, needing to use back-up arrangements had small positive associations with parenting stress, which partially mediated the relationship between that type of care instability and child externalizing behavior problems.
Exposure to stressful life events during pregnancy predicts psychotic experiences via behaviour problems in childhood.

Science.gov (United States)

Betts, Kim S; Williams, Gail M; Najman, Jakob M; Scott, James; Alati, Rosa

2014-12-01

Exposure to stressful life events during pregnancy has been associated with later schizophrenia in offspring. We explore how prenatal stress and neurodevelopmental abnormalities in childhood associate to increase the risk of later psychotic experiences. Participants from the Mater University Study of Pregnancy (MUSP), an Australian based, pre-birth cohort study were examined for lifetime DSM-IV positive psychotic experiences at 21 years by a semi-structured interview (n = 2227). Structural equation modelling suggested psychotic experiences were best represented with a bifactor model including a general psychosis factor and two group factors. We tested for an association between prenatal stressful life events with the psychotic experiences, and examined for potential moderation and mediation by behaviour problems and cognitive ability in childhood. Prenatal stressful life events predicted psychotic experiences indirectly via behaviour problems at child age five years, and this relationship was not confounded by maternal stressful life events at child age five. We found no statistical evidence for an interaction between prenatal stressful life events and behaviour problems or cognitive ability. The measurable effect of prenatal stressful life events on later psychotic experiences in offspring manifested as behaviour problems by age 5. By identifying early abnormal behavioural development as an intermediary, this finding further confirms the role of prenatal stress to later psychotic disorders. Copyright © 2014 Elsevier Ltd. All rights reserved.
Predicting the change of child’s behavior problems: sociodemographic and maternal parenting stress factors

OpenAIRE

Viduolienė, Evelina

2013-01-01

Purpose: evaluate 1) whether child’s externalizing problems increase or decrease within 12 months period; 2) the change of externalizing problems with respect to child gender and age, and 3) which maternal parenting stress factors and family sociodemographic characteristics can predict the increase and decrease of child’s externalizing problems. Design/methodology/approach: participants were evaluated 2 times (with the interval of 12 months) with the Parenting Stress Index (Abidin, 1990) and ...
Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

Science.gov (United States)

Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

2017-01-01

Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to…
Integration and the hold-up problem in the design organization for engineering projects

NARCIS (Netherlands)

Zerjav, Vedran; Hartmann, Timo; Javernick-Will, A.; Chinowsky, P.

2012-01-01

The paper presents a perspective of the design organization in engineering projects based on the economic concept of the hold-up problem. By integrating the economic theories on the boundaries of organizations into the existing knowledge on design in engineering projects, the paper hypothesizes a
Solving computationally expensive engineering problems

CERN Document Server

Leifsson, Leifur; Yang, Xin-She

2014-01-01

Computational complexity is a serious bottleneck for the design process in virtually any engineering area. While migration from prototyping and experimental-based design validation to verification using computer simulation models is inevitable and has a number of advantages, high computational costs of accurate, high-fidelity simulations can be a major issue that slows down the development of computer-aided design methodologies, particularly those exploiting automated design improvement procedures, e.g., numerical optimization. The continuous increase of available computational resources does not always translate into shortening of the design cycle because of the growing demand for higher accuracy and necessity to simulate larger and more complex systems. Accurate simulation of a single design of a given system may be as long as several hours, days or even weeks, which often makes design automation using conventional methods impractical or even prohibitive. Additional problems include numerical noise often pr...

Collaborative Systems Thinking: A Response to the Problems Faced by Systems Engineering's 'Middle Tier'

Science.gov (United States)

Phfarr, Barbara B.; So, Maria M.; Lamb, Caroline Twomey; Rhodes, Donna H.

2009-01-01

Experienced systems engineers are adept at more than implementing systems engineering processes: they utilize systems thinking to solve complex engineering problems. Within the space industry demographics and economic pressures are reducing the number of experienced systems engineers that will be available in the future. Collaborative systems thinking within systems engineering teams is proposed as a way to integrate systems engineers of various experience levels to handle complex systems engineering challenges. This paper uses the GOES-R Program Systems Engineering team to illustrate the enablers and barriers to team level systems thinking and to identify ways in which performance could be improved. Ways NASA could expand its engineering training to promote team-level systems thinking are proposed.
Ensuring Structural Integrity through Reliable Residual Stress Measurement: From Crystals to Crankshafts

International Nuclear Information System (INIS)

Edwards, Lyndon

2005-01-01

Full text: The determination of accurate, reliable stresses is critical to many fields of engineering and, in particular, the structural integrity and hence, safety, of many systems. Neutron stress measurement is a non-destructive technique that uniquely provides insights into stress fields deep within components and structures. As such, it has become an increasingly important tool within the engineering community leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise structural integrity lifting procedures. This talk describes the current state of the art and identifies the key opportunities for improved structural integrity provided by the 2nd generation dedicated engineering stress diffractometers currently being designed and commissioned world-wide. Examples are provided covering a range of industrially relevant problems from the fields. (author)
Self-stress control of real civil engineering tensegrity structures

Science.gov (United States)

Kłosowska, Joanna; Obara, Paulina; Gilewski, Wojciech

2018-01-01

The paper introduces the impact of the self-stress level on the behaviour of the tensegrity truss structures. Displacements for real civil engineering tensegrity structures are analysed. Full-scale tensegrity tower Warnow Tower which consists of six Simplex trusses is considered in this paper. Three models consisting of one, two and six modules are analysed. The analysis is performed by the second and third order theory. Mathematica software and Sofistik programme is applied to the analysis.
Decision Analysis on Survey and SOil Investigation Problem in Power Engineering Consultant

OpenAIRE

Setyaman, Amy Maulany; Sunitiyoso, Yos

2013-01-01

The study aims to gather and organize information for decision making against the problems arising in Power Engineering Consultant's survey and soil investigation product due to new policy in production cost efficiency that is implemented in 2012. The study conducted using Kepner and Tragoe's analytical process that consisted of four stages analytical process such as situation analysis, problem analysis, decision making analysis and potential problem analysis. As for the decision making analy...
The co-development of parenting stress and childhood internalizing and externalizing problems

NARCIS (Netherlands)

Stone, L.L.; Mares, S.H.W.; Otten, R.; Engels, R.C.M.E.; Janssens, J.M.A.M.

2016-01-01

Although the detrimental influence of parenting stress on child problem behavior is well established, it remains unknown how these constructs affect each other over time. In accordance with a transactional model, this study investigates how the development of internalizing and externalizing problems
Engineering Encounters: Identifying an Engineering Design Problem

Science.gov (United States)

Chizek, Lisa; VanMeeteren, Beth; McDermott, Mark; Uhlenberg, Jill

2018-01-01

Engineering is an intriguing way for students to connect the design process with their knowledge of science (NRC 2012). This article describes the "Engineering a Pancake Recipe" design process which was created to make the structure and properties of matter more meaningful for fifth grade students. The whole pancake recipe engineering…
Parenting stress and child behavior problems among clinic-referred youth: cross-cultural differences across the US and Korea.

Science.gov (United States)

Chung, Kyong-Mee; Ebesutani, Chad; Bang, Hye Min; Kim, Joohee; Chorpita, Bruce F; Weisz, John R; Suh, Dongsoo; Byun, Heejung

2013-06-01

Due to increased multiculturalism in the US and abroad, there is a need for increased understanding of the different ways in which parenting stress is related to child problems across cultures. In the present study, we investigated (a) differences in reported parenting stress and childhood problem behaviors across a Korean (n = 71) and US (n = 71) sample, as well as (b) differences in the ways in which parenting stress and childhood problems were related across Korean and US children based on mothers' reports. Results revealed that Korean mothers reported significantly higher parenting stress yet significantly lower childhood problem behaviors compared to US mothers. In addition, mother-based reports of child problems were significantly associated with parenting stress in the US sample, but not in the Korean sample. Clinical implications and culturally-relevant issues relevant to these findings are addressed, including a potential under-reporting bias of child problems among Asian parents.
Mindfulness and Alcohol Problems in College Students: The Mediating Effects of Stress

Science.gov (United States)

Bodenlos, Jamie S.; Noonan, Marleah; Wells, Stephanie Y.

2013-01-01

Objective: To examine the relationship between mindfulness and alcohol problems in college students, as well as the role of stress as a mediator in this relationship. Participants: Participants were 310 students from a small, private college in the Northeast. Methods: Students completed self-report measures, including the Perceived Stress Scale,…
An ocean of stress? The relationship between psychosocial workload and mental strain among engine officers in the Swedish merchant fleet.

Science.gov (United States)

Rydstedt, Leif W; Lundh, Monica

2010-01-01

The first purpose of this study was to compare the psychosocial working conditions and mental health of our sample of maritime engine officers with a sample of British shore-based professional engineers. The second purpose was to analyse the relationship between the psychosocial working conditions onboard and mental strain for the Swedish maritime engine officers. There were a total of 731 engine officers in the Swedish merchant fleet, almost all males with higher education. The British comparison sample consisted of 312 professional shore-based engineers. A questionnaire was distributed to the Swedish engine officers with a modified version of the JCQ for the DC-S model, the Role conflict and Ambiguity scale, and two items on family-work inter-role conflicts (WFI/FWI), as workload indicators. The General Health Questionnaire (GHQ12) and Perceived Stress Scale (PSS10) were used as strain indicators. There were no significant differences in perceived job stain or in WFI/FWI between the Swedish engine officers and the British professional engineers in perceived job strain. While the British shore-based engineers reported significantly higher role ambiguity the Swedish engine officers perceived a significantly higher degree of role conflict and higher perceived stress. Hierarchic linear regression analysis showed that the Role Stress was strongly related to perceived stress (R(2) = 0.319) as well as to mental health (R(2) = 0.222). When introduced in the second step the DC-S model was significantly related to the outcome measures, as was WFI/FWI when finally introduced. The main source of the high degree of perceived stress among the engine officers does not seem to be the job content but may rather be understood from an interactional perspective, where conflicting requirements are directed towards the individual officer. It can be assumed that the fast technological and organizational changes and the increased pressure for economic profitability that characterize the
Child/Adolescent’s ADHD and Parenting Stress: The Mediating Role of Family Impact and Conduct Problems

Science.gov (United States)

Muñoz-Silva, Alicia; Lago-Urbano, Rocio; Sanchez-Garcia, Manuel; Carmona-Márquez, José

2017-01-01

Objective: The demands of parenting are usually associated with some stress, and elevated levels of stress may affect the parent–child relationships and parenting practices. This is especially the case of families where children have special needs conditions or disorders, like Attention Deficit Hyperactivity Disorder (ADHD). Method: This study examined parenting stress among mothers of children and adolescents with ADHD. The sample comprised 126 mothers of girls (36; 29%) and boys (90; 71%) aged 6–17 years old. Results: Mothers reported their own stress levels as well as the children and adolescents’ variables (severity of their ADHD symptoms, conduct, and emotional problems) and family–contextual variables (negative impact on family’s social life, impact on couple relationship, and perceived social support). Hierarchical multiple regression showed that (a) negative impact on social life and conduct problems were the strongest predictors of mother’s stress. Bootstrap mediation analyses revealed that (b) the association between child and adolescent’s ADHD and parenting stress was mediated by children’s conduct problems and by negative impact on family’s social life, and not by children’s emotional problems nor by mother’s perceived social support. The mediation analysis also suggested (c) a pathway from child/adolescent’s ADHD through children’s conduct problems and then through their negative impact on family’s social life to mother’s parenting stress. Conclusion: These results suggest that both child/adolescent’s and family factors should be considered in the designing of interventions for reducing parenting stress in families of children and adolescents with ADHD. PMID:29312090
Child/Adolescent’s ADHD and Parenting Stress: The Mediating Role of Family Impact and Conduct Problems

Directory of Open Access Journals (Sweden)

Alicia Muñoz-Silva

2017-12-01

Full Text Available Objective: The demands of parenting are usually associated with some stress, and elevated levels of stress may affect the parent–child relationships and parenting practices. This is especially the case of families where children have special needs conditions or disorders, like Attention Deficit Hyperactivity Disorder (ADHD.Method: This study examined parenting stress among mothers of children and adolescents with ADHD. The sample comprised 126 mothers of girls (36; 29% and boys (90; 71% aged 6–17 years old.Results: Mothers reported their own stress levels as well as the children and adolescents’ variables (severity of their ADHD symptoms, conduct, and emotional problems and family–contextual variables (negative impact on family’s social life, impact on couple relationship, and perceived social support. Hierarchical multiple regression showed that (a negative impact on social life and conduct problems were the strongest predictors of mother’s stress. Bootstrap mediation analyses revealed that (b the association between child and adolescent’s ADHD and parenting stress was mediated by children’s conduct problems and by negative impact on family’s social life, and not by children’s emotional problems nor by mother’s perceived social support. The mediation analysis also suggested (c a pathway from child/adolescent’s ADHD through children’s conduct problems and then through their negative impact on family’s social life to mother’s parenting stress.Conclusion: These results suggest that both child/adolescent’s and family factors should be considered in the designing of interventions for reducing parenting stress in families of children and adolescents with ADHD.
Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

Science.gov (United States)

Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

2017-08-01

Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to students' abilities to address WSPs. Specifically, we aim to (I) describe key constituents of engineering students' approaches to a WSP, (II) evaluate these approaches in relation to the normative context of education for sustainable development (ESD), and (III) identify relevant aspects of learning related to WSPs. Aim I is addressed through a phenomenographic study, while aims II and III are addressed by relating the results to research literature about human problem solving, sustainable development, and ESD. We describe four qualitatively different ways of approaching a specific WSP, as the outcome of the phenomenographic study: A. Simplify and avoid, B. Divide and control, C. Isolate and succumb, and D. Integrate and balance. We identify approach D as the most appropriate approach in the context of ESD, while A and C are not. On this basis, we identify three learning objectives related to students' abilities to address WSPs: learn to use a fully integrative approach, distinguish WSPs from tame and well-structured problems, and understand and consider the normative context of SD. Finally, we provide recommendations for how these learning objectives can be used to guide the design of science and engineering educational activities.
A Finite-Volume computational mechanics framework for multi-physics coupled fluid-stress problems

International Nuclear Information System (INIS)

Bailey, C; Cross, M.; Pericleous, K.

1998-01-01

Where there is a strong interaction between fluid flow, heat transfer and stress induced deformation, it may not be sufficient to solve each problem separately (i.e. fluid vs. stress, using different techniques or even different computer codes). This may be acceptable where the interaction is static, but less so, if it is dynamic. It is desirable for this reason to develop software that can accommodate both requirements (i.e. that of fluid flow and that of solid mechanics) in a seamless environment. This is accomplished in the University of Greenwich code PHYSICA, which solves both the fluid flow problem and the stress-strain equations in a unified Finite-Volume environment, using an unstructured computational mesh that can deform dynamically. Example applications are given of the work of the group in the metals casting process (where thermal stresses cause elasto- visco-plastic distortion)
Alcohol Demand, Future Orientation, and Craving Mediate the Relation Between Depressive and Stress Symptoms and Alcohol Problems.

Science.gov (United States)

Soltis, Kathryn E; McDevitt-Murphy, Meghan E; Murphy, James G

2017-06-01

Elevated depression and stress have been linked to greater levels of alcohol problems among young adults even after taking into account drinking level. This study attempts to elucidate variables that might mediate the relation between symptoms of depression and stress and alcohol problems, including alcohol demand, future time orientation, and craving. Participants were 393 undergraduates (60.8% female, 78.9% White/Caucasian) who reported at least 2 binge-drinking episodes (4/5+ drinks for women/men, respectively) in the previous month. Participants completed self-report measures of stress and depression, alcohol demand, future time orientation, craving, and alcohol problems. In separate mediation models that accounted for gender, race, and weekly alcohol consumption, future orientation and craving significantly mediated the relation between depressive symptoms and alcohol problems. Alcohol demand, future orientation, and craving significantly mediated the relation between stress symptoms and alcohol problems. Heavy-drinking young adults who experience stress or depression are likely to experience alcohol problems, and this is due in part to elevations in craving and alcohol demand, and less sensitivity to future outcomes. Interventions targeting alcohol misuse in young adults with elevated levels of depression and stress should attempt to increase future orientation and decrease craving and alcohol reward value. Copyright © 2017 by the Research Society on Alcoholism.
Structural Stress Analysis of an Engine Cylinder Head

Directory of Open Access Journals (Sweden)

R. Tichánek

2005-01-01

Full Text Available This paper deals with a structural stress analysis of the cylinder head assembly of the C/28 series engine. A detailed FE model was created for this purpose. The FE model consists of the main parts of the cylinder head assembly, and it includes a description of the thermal and mechanical loads and the contact interaction between their parts. The model considers the temperature dependency of the heat transfer coefficient on wall temperature in cooling passages. The paper presents a comparison of computed and measured temperature. The analysis was carried out using the FE program ABAQUS.
The problem of professional burnout in stress management

Directory of Open Access Journals (Sweden)

Makasheva Natalia

2016-01-01

Full Text Available The problem of professional burnout is extremely relevant in current stress management. By its nature, professional burnout is a unique type of stress syndrome that is characterized by emotional exhaustion. It leads to loss of energy and interest in one’s job. A burnout could be the result of such syndromes as – burnout and boreout. It could emerge as the reaction of the organism to the high working intensity and stress working conditions or due to the boredom and absence of the sphere for professional realization. Both syndromes negatively influence the professional activity and require serious research and an adequate approach to the study. Studies have been conducted in the higher educational environment and among production employees. The studies were conducted with the application of the existing tests for revealing the “boreout” and “burnout” syndromes. Studies have shown that the syndrome “burnout” is common among workers with free working regulations, whose work requires greater independence, initiative and responsibility. According to the results of the study, the employees who are more free in the performance of their professional duties (teachers, managers are less subjected to the boreout syndrome. For the prevention and control of professional burnout company management needs to apply the achievements of stress management.
On The Stress Free Deformation Of Linear FGM Interface Under Constant Temperature

Directory of Open Access Journals (Sweden)

Ganczarski Artur

2015-09-01

Full Text Available This paper demonstrates the stress free thermo-elastic problem of the FGM thick plate. Existence of such a purely thermal deformation is proved in two ways. First proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations. This reduces 3D problem to the plane stress state problem. Next it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient. Second proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation. This occurs if only stress field is homogeneous in domain and at boundary. Finally an example of application to an engineering problem is presented.
Depression and work related stress problems, with notes of comparative law.

Science.gov (United States)

Amorosi, Marilisa; Pettinelli, Roberto

2013-09-01

This paper supplies both a medical and legal analysis of work related stress problems, by going throught the role of prevention in the European legal system. The Authors, after reviewing the negative role that stress has in the management of the employment relationship, describe the main steps that have brought Europe to recognize the importance of the role of prevention, and to recognize the role of well-being in the workplace.
Integrated approach for stress analysis of high performance diesel engine cylinder head

Science.gov (United States)

Chainov, N. D.; Myagkov, L. L.; Malastowski, N. S.; Blinov, A. S.

2018-03-01

Growing thermal and mechanical loads due to development of engines with high level of a mean effective pressure determine requirements to cylinder head durability. In this paper, computational schemes for thermal and mechanical stress analysis of a high performance diesel engine cylinder head were described. The most important aspects in this approach are the account of temperature fields of conjugated details (valves and saddles), heat transfer modeling in a cooling jacket of a cylinder head and topology optimization of the detail force scheme. Simulation results are shown and analyzed.
Senior Design in Agricultural Engineering--Progress and Pitfalls.

Science.gov (United States)

Holmes, R. G.; Rohrbach, R. P.

1979-01-01

Describes a specific senior design course and its objectives. Explains the basic deficiencies and problems for design education in agricultural engineering. Also stresses the effect the project advisor has on students' attitudes toward design and the applications of the course. (SMB)

The Impact of Behaviour Problems on Caregiver Stress in Young People with Autism Spectrum Disorders

Science.gov (United States)

Lecavalier, L.; Leone, S.; Wiltz, J.

2006-01-01

Background: The purpose of this study was to examine the correlates of caregiver stress in a large sample of young people with autism spectrum disorders (ASDs). Two main objectives were to: (1) disentangle the effects of behaviour problems and level of functioning on caregiver stress; and (2) measure the stability of behaviour problems and…
The meaning and experience of stress among supported employment clients with mental health problems.

Science.gov (United States)

Besse, Christine; Poremski, Daniel; Laliberté, Vincent; Latimer, Eric

2018-05-01

Many clinicians are concerned that competitive work may cause excessive stress for people with severe mental health problems. Individual Placement and Support (IPS) is acknowledged as the most effective model of supported employment for this population. The manner in which IPS clients define and experience employment-related stress is poorly understood. This qualitative study aims to explore how people with mental health problems receiving IPS services define and experience employment-related stress. We purposively sampled and interviewed 16 clients of an IPS programme, who had been competitively employed for more than 1 month. Data were collected between September 2014 and July 2015 in Montreal, Canada. Transcripts of semi-structured interviews were analysed using grounded theory methodology. IPS clients often defined stress similar to its common understanding: the result of experiencing prolonged or/and cumulative strains, or of an incongruence between efforts and rewards, hopes and reality. Stress experienced in this way could exacerbate psychiatric symptoms, especially depression or psychotic symptoms. However, when maintained at a more manageable level, stress stimulated learning and improved planning of tasks. Participants described different coping mechanisms, such as sharing their experiences and difficulties with others, focusing on problem resolution and avoidance. The first two of these helped IPS clients remain at work and bolstered their confidence. Work-related stress has potentially positive as well as negative consequences for IPS clients. In order to maximise the potential beneficial effects of stress, employment specialists can help clients anticipate potential stressors and plan how they might cope with them. Further research on the most effective ways of helping clients cope with stress is needed. © 2017 John Wiley & Sons Ltd.
Parenting stress and children's problem behavior in China: the mediating role of parental psychological aggression.

Science.gov (United States)

Liu, Li; Wang, Meifang

2015-02-01

This study examined the mediating effect of parents' psychological aggression in the relationship between parenting stress and children's internalizing (anxiety/depression, withdrawal) and externalizing (aggression, delinquency) problem behaviors 1 year later. Using a sample of 311 intact 2-parent Chinese families with preschoolers, findings revealed that maternal parenting stress had direct effects on children's internalizing and externalizing problem behavior and indirect effects through maternal psychological aggression. However, neither direct nor indirect effects of fathers' parenting stress on children's internalizing and externalizing problem behavior were found. The findings highlight the importance of simultaneously studying the effects of both mothers' and fathers' parenting on their children within a family systems framework. PsycINFO Database Record (c) 2015 APA, all rights reserved.
Bitumen/Water Emulsions as Fuels for High-Speed Ci Engines Preliminary Investigations

DEFF Research Database (Denmark)

Schramm, Jesper; Sigvardsen, R.; Forman, M.

2003-01-01

Mixtures of bitumen and water, are cheap fuel alternatives for combustion engines. There are, however, several problems that have to be solved before these fuels can be applied in high-speed diesel engines. These are: - emulsion break up due to high temperature or high shear stress in the injection...
Engineering Courses on Computational Thinking Through Solving Problems in Artificial Intelligence

Directory of Open Access Journals (Sweden)

Piyanuch Silapachote

2017-09-01

Full Text Available Computational thinking sits at the core of every engineering and computing related discipline. It has increasingly emerged as its own subject in all levels of education. It is a powerful cornerstone for cognitive development, creative problem solving, algorithmic thinking and designs, and programming. How to effectively teach computational thinking skills poses real challenges and creates opportunities. Targeting entering computer science and engineering undergraduates, we resourcefully integrate elements from artificial intelligence (AI into introductory computing courses. In addition to comprehension of the essence of computational thinking, practical exercises in AI enable inspirations of collaborative problem solving beyond abstraction, logical reasoning, critical and analytical thinking. Problems in machine intelligence systems intrinsically connect students to algorithmic oriented computing and essential mathematical foundations. Beyond knowledge representation, AI fosters a gentle introduction to data structures and algorithms. Focused on engaging mental tool, a computer is never a necessity. Neither coding nor programming is ever required. Instead, students enjoy constructivist classrooms designed to always be active, flexible, and highly dynamic. Learning to learn and reflecting on cognitive experiences, they rigorously construct knowledge from collectively solving exciting puzzles, competing in strategic games, and participating in intellectual discussions.
Marital Satisfaction, Parental Stress, and Child Behavior Problems among Parents of Young Children with Developmental Delays

Science.gov (United States)

Robinson, Merideth; Neece, Cameron L.

2015-01-01

Studies have found that low marital satisfaction, parenting stress, and child behavior problems are linked in families of children with developmental delays (DD). However, previous investigations examining the relationships between parenting stress, child behavior problems, and marital satisfaction rarely examine the interrelationships of these…
Self-reported Stress Problems among Teachers in Hong Kong

Science.gov (United States)

Chan, Alan H. S.; Chen, K.; Chong, Elaine Y. L.

2010-10-01

The present study was developed to comprehensively investigate the occupational health problems among teachers of primary and secondary schools in Hong Kong. A random sample of 1,710 respondents was generated from the database of Hong Kong Professional Teachers' Union (HKPTU) members. A self-administrated questionnaire was designed and sent by mail to the teachers of primary and secondary schools in HK. The results indicated that comparing with one year and five years ago, 91.6% and 97.3% of the responding teachers reported an increase of perceived stress level, respectively. Heavy workload and time pressure, education reforms, external school review, pursuing further education, and managing students' behaviour and learning were the most frequently reported sources of work stress. The four most frequently reported stress management activities were sleeping, talking to neighbors and friends, self-relaxing, and watching television, while the least frequently reported activity was doing more exercises or sports.
Automotive and Construction Equipment for Arctic Use, Materials Problems

Science.gov (United States)

1991-11-01

followed. Nitrile rubber ( NBR ) is one of the most common materials used in seal manufacture. It is a copolymer of butadiene and acrylonitrile and is... rubber and other elastomers, and many plastics. This problem is exacerbated, especially in equipment with diesel engines, because the engines run...their original condition in a short time on removal of the stress. The group includes natural rubbers as well as synthetic polymers. Many of these
Predicting Maternal Parenting Stress in Middle Childhood: The Roles of Child Intellectual Status, Behaviour Problems and Social Skills

Science.gov (United States)

Neece, C.; Baker, B.

2008-01-01

Background: Parents of children with intellectual disabilities (ID) typically report elevated levels of parenting stress, and child behaviour problems are a strong predictor of heightened parenting stress. Interestingly, few studies have examined child characteristics beyond behaviour problems that may also contribute to parenting stress. The…
Engineering-Based Problem Solving in the Middle School: Design and Construction with Simple Machines

Science.gov (United States)

English, Lyn D.; Hudson, Peter; Dawes, Les

2013-01-01

Incorporating engineering concepts into middle school curriculum is seen as an effective way to improve students' problem-solving skills. A selection of findings is reported from a science, technology, engineering and mathematics (STEM)-based unit in which students in the second year (grade 8) of a three-year longitudinal study explored…
Predictors of child functioning and problem behaviors for children diagnosed with posttraumatic stress disorder and externalizing problems.

Science.gov (United States)

Nabors, Laura; Baker-Phibbs, Christina; Burbage, Michelle

2016-01-01

Posttraumatic stress disorder and behavioral disorders are related to problems in emotional functioning for young children. Factors related to child functioning are important to understand in order to develop interventions and assess their impact. This study examined clinician and parent reports of child functioning and behavior problems and factors related to each of these outcome variables. Results indicated that parental acceptance was inversely related to child behavior problems. Increased parental supervision of the child was related to high total problems scores. Parental acceptance was positively related to child functioning. Future research is needed to examine relations among interventions to improve parental supervision and interactions with the child and child functioning, in terms of both positive and negative behaviors.
Effect of fin attachment on thermal stress reduction of exhaust manifold of an off road diesel engine

Institute of Scientific and Technical Information of China (English)

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

2017-01-01

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

Science.gov (United States)

Naseem, Sabahat; Munaf, Seema

2017-01-01

Pursuing higher education is not an easy task as it requires hard work, dedication, and motivation. Although there are many rewards involved in growing up academically, nevertheless, it contains a few hazards too. For instance, suicidal ideation is associated with presence of depression, anxiety, and stress with low level of satisfaction with life in students finding difficulty in handling educational demands of higher education. Therefore, the present study focused on the query that whether there is any difference or not among medical, engineering, and social sciences students of city of Karachi, Pakistan in the level of suicidal ideation, depression, anxiety, stress, and life satisfaction. Using comparative group design, total 300 students (150 males and 150 females) with age range of 19-26 were selected from faculties of medical, engineering, and social sciences of different universities of Karachi, Pakistan, through purposive sampling. Respondent Profile Form, The Suicide Behaviours Questionnaire-Revised, Depression Anxiety Stress Scale-21, and Satisfaction with Life Scale were administered to assess suicidal ideation; depression, anxiety, stress; and life satisfaction, respectively, of the students. Scores were analysed through ANOVA and Post Hoc (Tukey's HSD) test using SPSS. Social sciences and engineering students were significantly higher on depression, anxiety, and stress than medical students [F (2, 297) =8.701, p=.000] whereas insignificant differences in the level of suicidal ideation [F (2, 297) =1.914, p=.149] and life satisfaction [F (2, 297) = .726, p = .485] among these students were found. With the help of these findings, it would be easier to counsel students of different disciplines in time on the lines of suggested preventive measures.
APPLYING PROFESSIONALLY ORIENTED PROBLEMS OF MATHEMATICAL MODELING IN TEACHING STUDENTS OF ENGINEERING DEPARTMENTS

Directory of Open Access Journals (Sweden)

Natal’ya Yur’evna Gorbunova

2017-06-01

Full Text Available We described several aspects of organizing student research work, as well as solving a number of mathematical modeling problems: professionally-oriented, multi-stage, etc. We underlined the importance of their economic content. Samples of using such problems in teaching Mathematics at agricultural university were given. Several questions connected with information material selection and peculiarities of research problems application were described. Purpose. The author aims to show the possibility and necessity of using professionally-oriented problems of mathematical modeling in teaching Mathematics at agricultural university. The subject of analysis is including such problems into educational process. Methodology. The main research method is dialectical method of obtaining knowledge of finding approaches to selection, writing and using mathematical modeling and professionally-oriented problems in educational process; the methodology is study of these methods of obtaining knowledge. Results. As a result of analysis of literature, students opinions, observation of students work, and taking into account personal teaching experience, it is possible to make conclusion about importance of using mathematical modeling problems, as it helps to systemize theoretical knowledge, apply it to practice, raise students study motivation in engineering sphere. Practical implications. Results of the research can be of interest for teachers of Mathematics in preparing Bachelor and Master students of engineering departments of agricultural university both for theoretical research and for modernization of study courses.
Gambling cognition and subjective well-being as mediators between perceived stress and problem gambling: a cross-cultural study on White and Chinese problem gamblers.

Science.gov (United States)

Tang, Catherine So-Kum; Oei, Tian Po

2011-09-01

This study aimed to delineate various pathways whereby cognitive and emotional vulnerabilities triggered by stress would lead to disruptive gambling. A multiple mediation framework was proposed to specify that gambling cognition and subjective well-being would mediate the influence of perceived stress on problem gambling. The cross-cultural validity of the proposed framework was examined with 132 White gamblers in Australia and 154 Chinese gamblers in China. They completed psychological scales on perceived stress, gambling expectancy bias, gambling refusal efficacy, negative affect, life satisfaction, and problem gambling. Compared to Chinese gamblers, White gamblers reported higher levels of perceived stress, gambling expectancy bias, and problem gambling as well as more pervasive negative affect and lower levels of life satisfaction. Results showed that the proposed multiple mediation framework fit the data better than two alternative plausible models. Life satisfaction and gambling refusal efficacy were two consistent mediators across White and Chinese gamblers. (c) 2011 APA, all rights reserved.
EXPLORING THE PROBLEMS FACED BY TECHNICAL SCHOOL STUDENTS IN LEARNING ENGINEERING COURSES

Directory of Open Access Journals (Sweden)

RAMLEE MUSTAPHA

2014-12-01

Full Text Available The teaching of engineering courses is relatively challenging due to the nature of the courses that are perceived as “difficult courses” by a number of students. Thus, the purpose of this action research was to explore the problems faced by electrical and electronic engineering (PKEE students studying a difficult topic–transistor. This research was also aimed at identifying the students’ attitude towards Problem-based Learning (PBL. Literature has shown that PBL could enhance students’ understanding and make the learning more meaningful. The theoretical framework of this study was based on Kemmis and Mc Taggart model. Cooperative learning method was also utilised in this study consisted of Jigsaw technique in the first and second rounds of the study. In the final round, the discussion method was used. In an action research design, a classroom is a usual research site. Thus, an engineering class of 30 Form 5 students in a Technical School was selected. The PBL method was applied in the class for a nine-week duration. Empirical data were gathered from peer assessment, observation, and pre- and post-tests. The data were described descriptively using frequency, mean and standard deviation. The main results show that the students were more interactive and their post-test result shows significant increases. In terms of the attitude towards PBL, the participants rated PBL highly. The participants also assert that the main benefits of PBL include enhancing their collaborative and problem-solving skills.
Financial stress, parent functioning and adolescent problem behavior: an actor-partner interdependence approach to family stress processes in low-, middle-, and high-income families.

Science.gov (United States)

Ponnet, Koen

2014-10-01

The family stress model proposes that financial stress experienced by parents is associated with problem behavior in adolescents. The present study applied an actor-partner interdependence approach to the family stress model and focused on low-, middle-, and high-income families to broaden our understanding of the pathways by which the financial stress of mothers and fathers are related to adolescent outcomes. The study uses dyadic data (N = 798 heterosexual couples) from the Relationship between Mothers, Fathers and Children study in which two-parent families with an adolescent between 11 and 17 years of age participated. Path-analytic results indicated that in each of the families the association between parents' financial stress and problem behavior in adolescents is mediated through parents' depressive symptoms, interparental conflict, and positive parenting. Family stress processes also appear to operate in different ways for low-, middle-, and high-income families. In addition to a higher absolute level of financial stress in low-income families, financial stress experienced by mothers and fathers in these families had significant direct and indirect effects on problem behavior in adolescents, while in middle- and high-income families only significant indirect effects were found. The financial stress of a low-income mother also had a more detrimental impact on her level of depressive feelings than it had on mothers in middle-income families. Furthermore, the study revealed gender differences in the pathways of mothers and fathers. Implications for research, clinical practice, and policy are also discussed.
Sample environment for neutron scattering measurements of internal stresses in engineering materials in the temperature range of 6 K to 300 K.

Science.gov (United States)

Kirichek, O; Timms, J D; Kelleher, J F; Down, R B E; Offer, C D; Kabra, S; Zhang, S Y

2017-02-01

Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.
Technical problems and future underground engineering experiments

Energy Technology Data Exchange (ETDEWEB)

Higgins, G H [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1969-07-01

The technical problems to be solved in future underground engineering experiments are of two kinds. One concerns adequate description of the variation of nuclear explosion effects with physical nd chemical properties of the explosion site. The other concerns engineering of the explosive detonation system to provide adequate safety and security, concurrently with minimum total costs per explosion. The semiempirical equations for explosion effects can be trusted only in the range of explosive energy, depth of burst, and rock type for which there is prior experience. Effects calculations based on the principles of continuum mechanics and measurable geophysical properties appear to work in the few test cases, such as Gasbuggy, to which they have been applied. These calculational methods must be tested in a variety of situations. The relevance of dynamic and static measurements on Dragon Trail, Bronco, Rulison, Stoop, Ketch, and Pinedale to proving the methods are discussed in this paper. The traditional methods of assembling and fielding nuclear explosives have evolved from practice at the Nevada Test Site. These provide great flexibility and assure maximum recovery of all data from each test, thus minimizing the time required to achieve desired results. Timing and firing, radiation monitoring, explosives assembly and emplacement, explosive performance, weather monitoring, and dynamic measurements of earth and building motion have all been handled traditionally as independent functions. To achieve lower costs in underground engineering experiments and projects, one prototype system combining all electronic, measurement, and communication functions is being built. Much further work will be required to complete this effort, including, especially, an examination of safety criteria and means for assuring operational and public safety at reduced costs. (author)
Technical problems and future underground engineering experiments

International Nuclear Information System (INIS)

Higgins, G.H.

1969-01-01

The technical problems to be solved in future underground engineering experiments are of two kinds. One concerns adequate description of the variation of nuclear explosion effects with physical nd chemical properties of the explosion site. The other concerns engineering of the explosive detonation system to provide adequate safety and security, concurrently with minimum total costs per explosion. The semiempirical equations for explosion effects can be trusted only in the range of explosive energy, depth of burst, and rock type for which there is prior experience. Effects calculations based on the principles of continuum mechanics and measurable geophysical properties appear to work in the few test cases, such as Gasbuggy, to which they have been applied. These calculational methods must be tested in a variety of situations. The relevance of dynamic and static measurements on Dragon Trail, Bronco, Rulison, Stoop, Ketch, and Pinedale to proving the methods are discussed in this paper. The traditional methods of assembling and fielding nuclear explosives have evolved from practice at the Nevada Test Site. These provide great flexibility and assure maximum recovery of all data from each test, thus minimizing the time required to achieve desired results. Timing and firing, radiation monitoring, explosives assembly and emplacement, explosive performance, weather monitoring, and dynamic measurements of earth and building motion have all been handled traditionally as independent functions. To achieve lower costs in underground engineering experiments and projects, one prototype system combining all electronic, measurement, and communication functions is being built. Much further work will be required to complete this effort, including, especially, an examination of safety criteria and means for assuring operational and public safety at reduced costs. (author)

Mechatronic Control Engineering: A Problem Oriented And Project Based Learning Curriculum In Mechatronic

DEFF Research Database (Denmark)

Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard

2008-01-01

Mechatronics is a field of multidisciplinary engineering that not only requires knowledge about different technical areas, but also insight into how to combine technologies optimally, to design efficient products and systems.This paper addresses the group project based and problem-oriented learning...... the well established methods from control engineering form very powerful techniques in both analysis and synthesis of mechatronic systems. The necessary skills for mechatronic engineers are outlined followed up by a discussion on how problem oriented project based learning is implemented. A complete...... curriculum named Mechatronic Control Engineering is presented, which is started at Aalborg University, Denmark, and the content of the semesters and projects are described. The projects are all characterized by the use of simulation and control for the purpose of analyzing and designing complex commercial...
The Relations among Maternal Health Status, Parenting Stress, and Child Behavior Problems in Low-Income, Ethnic-Minority Families

Science.gov (United States)

BeLue, Rhonda; Halgunseth, Linda C.; Abiero, Beatrice; Bediako, Phylicia

2015-01-01

Objectives Minimal attention has been given to understanding parenting stress among low-income, ethnically diverse mothers of children with conduct problems. Maternal health and parenting hassles may serve as important risk factors for parenting stress. This study examined whether parenting hassles moderated the relations between maternal physical and mental health and parenting stress in a sample of low-income, ethnically diverse mothers of children with behavioral problems. Methods The sample included 177 low-income Black, Latina, and White mothers of kindergartners with behavior problems. PATH analysis was employed to assess the associations between maternal mental and physical health and parenting stress, as well as the moderating role of parenting hassles in this cross-sectional study. Results After adjusting for covariates, we found that parenting hassles mediates the relationship between social support and parenting stress as well as maternal health and parenting stress. Conclusion Findings suggest that promoting coping resources for daily parenting hassles and supporting the physical and mental health of minority mothers may have important implications for parenting children with high behavior problems. PMID:26863556
Application of an engineering problem-solving methodology to address persistent problems in patient safety: a case study on retained surgical sponges after surgery.

Science.gov (United States)

Anderson, Devon E; Watts, Bradley V

2013-09-01

Despite innumerable attempts to eliminate the postoperative retention of surgical sponges, the medical error persists in operating rooms worldwide and places significant burden on patient safety, quality of care, financial resources, and hospital/physician reputation. The failure of countless solutions, from new sponge counting methods to radio labeled sponges, to truly eliminate the event in the operating room requires that the emerging field of health-care delivery science find innovative ways to approach the problem. Accordingly, the VA National Center for Patient Safety formed a unique collaboration with a team at the Thayer School of Engineering at Dartmouth College to evaluate the retention of surgical sponges after surgery and find a solution. The team used an engineering problem solving methodology to develop the best solution. To make the operating room a safe environment for patients, the team identified a need to make the sponge itself safe for use as opposed to resolving the relatively innocuous counting methods. In evaluation of this case study, the need for systematic engineering evaluation to resolve problems in health-care delivery becomes clear.
Testing Foreign Language Impact on Engineering Students' Scientific Problem-Solving Performance

Science.gov (United States)

Tatzl, Dietmar; Messnarz, Bernd

2013-01-01

This article investigates the influence of English as the examination language on the solution of physics and science problems by non-native speakers in tertiary engineering education. For that purpose, a statistically significant total number of 96 students in four year groups from freshman to senior level participated in a testing experiment in…
Case study of a problem-based learning course of physics in a telecommunications engineering degree

Science.gov (United States)

Macho-Stadler, Erica; Jesús Elejalde-García, Maria

2013-08-01

Active learning methods can be appropriate in engineering, as their methodology promotes meta-cognition, independent learning and problem-solving skills. Problem-based learning is the educational process by which problem-solving activities and instructor's guidance facilitate learning. Its key characteristic involves posing a 'concrete problem' to initiate the learning process, generally implemented by small groups of students. Many universities have developed and used active methodologies successfully in the teaching-learning process. During the past few years, the University of the Basque Country has promoted the use of active methodologies through several teacher training programmes. In this paper, we describe and analyse the results of the educational experience using the problem-based learning (PBL) method in a physics course for undergraduates enrolled in the technical telecommunications engineering degree programme. From an instructors' perspective, PBL strengths include better student attitude in class and increased instructor-student and student-student interactions. The students emphasised developing teamwork and communication skills in a good learning atmosphere as positive aspects.
On a class of problems on interaction of stress concentrators of different types with an elastic semi-infinite plate

Science.gov (United States)

Mkhitaryan, S. M.

2018-04-01

A class of mixed boundary-value problems of mathematical theory of elasticity dealing with interaction between stress concentrators of different types (such as cracks, absolutely rigid thin inclusions, punches, and stringers) and an elastic semi-infinite plate is considered. The method of Mellin integral transformation is used to reduce solving these problems to solving singular integral equations (SIE). After the governing SIE are solved, the following characteristics of the problem are determined: tangential contact stresses under stringers, dislocation density on the crack edges, breaking stresses outside the cracks on their line of location, the stress intensity factor (SIF), crack openings, jumps of contact stresses on the edges of inclusions.
Relevance of plastic limit loads to reference stress approach for surface cracked cylinder problems

International Nuclear Information System (INIS)

Kim, Yun-Jae; Shim, Do-Jun

2005-01-01

To investigate the relevance of the definition of the reference stress to estimate J and C* for surface crack problems, this paper compares finite element (FE) J and C* results for surface cracked pipes with those estimated according to the reference stress approach using various definitions of the reference stress. Pipes with part circumferential inner surface cracks and finite internal axial cracks are considered, subject to internal pressure and global bending. The crack depth and aspect ratio are systematically varied. The reference stress is defined in four different ways using (i) a local limit load (ii), a global limit load, (iii) a global limit load determined from the FE limit analysis, and (iv) the optimised reference load. It is found that the reference stress based on a local limit load gives overall excessively conservative estimates of J and C*. Use of a global limit load clearly reduces the conservatism, compared to that of a local limit load, although it can sometimes provide non-conservative estimates of J and C*. The use of the FE global limit load gives overall non-conservative estimates of J and C*. The reference stress based on the optimised reference load gives overall accurate estimates of J and C*, compared to other definitions of the reference stress. Based on the present findings, general guidance on the choice of the reference stress for surface crack problems is given
[Effects on Stress, Problem Solving Ability and Quality of Life of as a Stress Management Program for Hospitalized Schizophrenic Patients: Based on the Stress, Appraisal-Coping Model of Lazarus & Folkman].

Science.gov (United States)

Park, Sun Ah; Sung, Kyung Mi

2016-08-01

The study was done to evaluate the effects a Stress Management Program (SMP) on stress, problem solving skills, and quality of life for hospitalized patients with Schizophrenia. A mixed method design was used: a combination of a repeated-measure design with a non-equivalent control group and qualitative data collection. The participants were 40 patients with schizophrenia admitted in three psychiatric hospitals. The experimental group (n=20) received the SMP twice a week for a total of 8 weeks. Study results revealed that the SMP was effective for stress (F=321.02, pproblem solving ability (F=246.28, peffective strategy to reduce patients' hospitalization stress, and improve problem solving skills and quality of life. Therefore, it is recommended that mental health nurses use this stress management program in clinical practice to assist adaptation to hospitalization for persons with schizophrenia.
Systems engineering: A problem of perception

Energy Technology Data Exchange (ETDEWEB)

Senglaub, M.

1995-08-01

The characterization of systems engineering as a discipline, process, procedure or a set of heuristics will have an impact on the implementation strategy, the training methodology, and operational environment. The systems engineering upgrade activities in the New Mexico Weapons Development Center and a search of systems engineering related information provides evidence of a degree of ambiguity in this characterization of systems engineering. A case is made in this article for systems engineering being the engineering discipline applied to the science of complexity. Implications of this characterization and some generic issues are delineated with the goal of providing an enterprise with a starting point for developing its business environment.
Toward Teaching Methods that Develop Learning and Enhance Problem Solving Skills in Engineering Students

Science.gov (United States)

Loji, K.

2012-01-01

Problem solving skills and abilities are critical in life and more specifically in the engineering field. Unfortunately, significant numbers of South African students who are accessing higher education lack problem solving skills and this results in poor academic performance jeopardizing their progress especially from first to second year. On the…
Work demands are related to mental health problems for older engine room officers.

Science.gov (United States)

Rydstedt, Leif W; Lundh, Monica

2012-01-01

The aim of the present study was to analyse the main and interaction effects of age and psychosocial work demands on mental wellbeing in a sample (N = 685; age M = 47 years) of engine room officers in the Swedish merchant fleet. As expected, work demands were highly related to general mental health as well as to perceived stress, while the main effect of age only related significantly to perceived stress. The interaction effects between high work demands and high age significantly explained the variance of general mental health as well as perceived stress. The results can be understood as a consequence of the rapid technological and organisational development in the shipping industry and suggest that it ought be of high priority to provide older employees with work-related resources to support their long-term work performance as well as their health and wellbeing.
The Implementation and Evaluation of a Project-Oriented Problem-Based Learning Module in a First Year Engineering Programme

Science.gov (United States)

McLoone, Seamus C.; Lawlor, Bob J.; Meehan, Andrew R.

2016-01-01

This paper describes how a circuits-based project-oriented problem-based learning educational model was integrated into the first year of a Bachelor of Engineering in Electronic Engineering programme at Maynooth University, Ireland. While many variations of problem based learning exist, the presented model is closely aligned with the model used in…
Parenting stress as a mediator of parents' negative mood state and behavior problems in children with newly diagnosed cancer.

Science.gov (United States)

van der Geest, Ivana M; van den Heuvel-Eibrink, Marry M; Passchier, Jan; van den Hoed-Heerschop, Corry; Pieters, Rob; Darlington, Anne-Sophie E

2014-07-01

The aim was to investigate the influence of parents' negative mood state and parenting stress on behavior in children with newly diagnosed cancer. A total of 123 parents (n=58 fathers, n=65 mothers) of 67 children with newly diagnosed cancer completed three questionnaires separately at the same time measuring parents' negative mood state, parenting stress, and child behavior problems. Parents' negative mood state was weakly correlated to more child behavior problems (r=0.31, pparenting stress were strongly correlated to more child behavior problems (r=0.61, pparents' negative mood state and child behavior problems (c=0.29, p=0.02 (fathers); c=0.25, p=0.04 (mothers)) became non-significant after mediating for parenting stress (c'=0.003, p=0.98 (fathers); c'=0.10, p=0.42 (mothers)). The indirect effect of parents' negative mood state and child behavior problems was only significant for fathers (95% CI [0.12; 0.51]), indicating that parenting stress mediates the effect between fathers' negative mood state and child behavior problems. This is the first study to demonstrate the mediational role of parenting stress in fathers of a child with newly diagnosed cancer. Copyright © 2014 John Wiley & Sons, Ltd.
22q11.2 deletion syndrome: behaviour problems of children and adolescents and parental stress.

Science.gov (United States)

Briegel, W; Schneider, M; Schwab, K Otfried

2008-11-01

22q11.2 deletion syndrome can be associated with a variety of somatic symptoms, developmental delays and psychiatric disorders. At present, there is little information on behaviour problems, parental stress and possible relations between these factors. Therefore, this study investigates behaviour problems of children and adolescents with 22q11.2DS, and their primary caregivers' stress. Parents of 4-17 year old subjects known to the German 22q11.2 deletion syndrome foundation were anonymously asked to fill out several questionnaires, e.g. the Child Behavior Checklist 4-18 (CBCL/4-18). The primary caregivers of 77/126 children [43 males, 34 females, mean age: 8;0 (4;0-16;11) years] sent back filled-out questionnaires. Forty-six of 76 subjects were rated as clinical on at least one of the CBCL-scales. Males had significantly higher scores on the total problems scale and the internalizing problems scale than females. The patients' age correlated with several CBCL-scales. Eleven of 49 subjects were suspicious of an autism spectrum disorder. Compared with the general population, but not with other parents of mentally and/or physically handicapped children, the primary caregivers experienced higher levels of stress, but showed normal life satisfaction. In spite of high rates of clinical behaviour problems among children and adolescents with 22q11.2DS and despite increased parental stress, most primary caregivers seem to have effective coping strategies, e.g. partnership support, to sustain normal levels of life satisfaction.
Applications of artificial intelligence in engineering problems. Vol. 1 and 2. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Sriram, D; Adey, R [eds.

1986-01-01

The purpose of the first international conference on the application of AI to engineering problems is to provide a forum for engineers all over the world to present their work on these applications. The interest being shown in the engineering community is evident by the large number of papers from the conference that are compiled into these volumes. The topics span various engineering disciplines. These topics are grouped into the following categories: - Knowledge representation and acquisition. Robotics. Natural language processing. Inexact inference techniques. General design methodologies. Constraints. Design strategies specific to a particular domain. Diagnostic systems. Intelligent front ends. Tools and techniques for building expert systems. Most of the papers deal with knowledge-based expert systems. In addition to the regular sessions, two sessions discussing a number of ongoing projects were also included in the conference. A panel on the future of AI in the engineering industry and another panel on networking were scheduled. Distinguished invited speakers from academia and industry presented lectures on their experiences with the application of AI.
THE TRAVELLING SALESMAN PROBLEM IN THE ENGINEERING EDUCATION PROGRAMMING CURRICULUM

OpenAIRE

Yevgeny Gayev; Vadim Kalmikov

2017-01-01

Objective: To make students familiar with the famous Traveling Salesman Problem (TSP) and suggest the latter to become a common exercise in engineering programming curriculum provided the students master computer science in the easy programming environment MATLAB. Methods: easy programming in MATLAB makes true such modern educational approach as “discovery based” methodology. Results: a MATLAB TSP-program oriented to Ukrainian map is suggested that allows to pictorially demonstrate the proces...
Differential relations between youth internalizing/externalizing problems and cortisol responses to performance vs. interpersonal stress.

Science.gov (United States)

Laurent, Heidemarie; Vergara-Lopez, Chrystal; Stroud, Laura R

2016-09-01

Efforts to define hypothalamic-pituitary-adrenal (HPA) axis profiles conferring risk for psychopathology have yielded inconclusive results, perhaps in part due to limited assessment of the stress response. In particular, research has typically focused on HPA responses to performance tasks, while neglecting the interpersonal stressors that become salient during adolescence. In this study we investigated links between psychosocial adjustment - youth internalizing and externalizing problems, as well as competence - and HPA responses to both performance and interpersonal stressors in a normative sample of children and adolescents. Participants (n = 59) completed a set of performance (public speaking, mental arithmetic, mirror tracing) and/or interpersonal (peer rejection) tasks and gave nine saliva samples, which were assayed for cortisol. Hierarchical linear models of cortisol response trajectories in relation to child behavior checklist (CBCL) scores revealed stressor- and sex-specific associations. Whereas internalizing problems related to earlier peaking, less dynamic cortisol responses to interpersonal stress (across males and females), externalizing problems related to lower, earlier peaking and less dynamic cortisol responses to performance stress for males only, and competence-related to later peaking cortisol responses to interpersonal stress for females only. Implications for understanding contextual stress profiles underlying different forms of psychopathology are discussed.
X-ray multiaxial stress analysis by means of polynomial approximation and an application to plane stress problem

International Nuclear Information System (INIS)

Yoshioka, Yasuo; Sasaki, Toshihiko; Kuramoto, Makoto.

1984-01-01

A new polynomial approximation method was proposed for the X-ray multiaxial stress analysis, in which the effect of stress gradient along the penetration depth of X-rays was taken into account. Three basic assumptions were made; (1) the stress gradient is linear in respect to the depth from the specimen surface, (2) the ponetration depth of X-rays is a function of Sin 2 phi and (3) the strain measured by X-rays corresponds to the weighted average strain on the intensity of the diffracted X-rays. Consequently, the stress state within the thin layer near the surface was expressed by making use of three surface stresses and six stress gradients in the present method. The average strains by X-rays were approximated by the third order polynomial equations of sin 2 phi using a least square method at several phi angles on the coordinate system of specimen. Since the coefficients of these polynomials include these nine stress components mentioned above, it is possible to solve them as simultaneous equations. The calculating process of this method is simpler than that of the integral method. An X-ray plane stress problem was analyzed as an application of the present method, and the residual stress distribution on a shot-peened steel plate was actually measured by use of Cr-Kα X-rays to verify the analysis. The result showed that the compressive residual stress near the surface determined by the present method was smaller than the weighted average stress by the Sin 2 phi method because of the steep stress gradient. The present method is useful to obtain a reasonable value of stress for such a specimen with steep stress gradients near the surface. (author)
Assessing the impact on intercultural competencies when engineering students solve problems in multicultural teams

DEFF Research Database (Denmark)

Jensen, Lars Peter; Nygaard, Bjørn; Madsen, Linda

2011-01-01

solving problems in teams two times a year in all of their bachelor education. In at least four of the engineering education institutes in Denmark experiments on helping mixed student teams to perform better in their project work have been carried out for some years using a classic engineering trial......’ intercultural competencies. It was decided to start a formal research project to investigate some of the existing experiments helping mixed teams to cope with project work in intercultural teams. During spring 2010 the setup for the research project was developed by a group of representatives from...... as exchange students or to take a full degree. Project organized Problem based Learning is used to a high extent at most of the engineering educations in Denmark, using large scale project work (up to 15 ECTS each semester) solved in teams (3-7 students in each team). In more and more situations the teams...
Providing Formative Assessment to Students Solving Multipath Engineering Problems with Complex Arrangements of Interacting Parts: An Intelligent Tutor Approach

Science.gov (United States)

Steif, Paul S.; Fu, Luoting; Kara, Levent Burak

2016-01-01

Problems faced by engineering students involve multiple pathways to solution. Students rarely receive effective formative feedback on handwritten homework. This paper examines the potential for computer-based formative assessment of student solutions to multipath engineering problems. In particular, an intelligent tutor approach is adopted and…

Uncertainty Quantification with Applications to Engineering Problems

DEFF Research Database (Denmark)

Bigoni, Daniele

in measurements, predictions and manufacturing, and we can say that any dynamical system used in engineering is subject to some of these uncertainties. The first part of this work presents an overview of the mathematical framework used in Uncertainty Quantification (UQ) analysis and introduces the spectral tensor...... and thus the UQ analysis of the associated systems will benefit greatly from the application of methods which require few function evaluations. We first consider the propagation of the uncertainty and the sensitivity analysis of the non-linear dynamics of railway vehicles with suspension components whose......-scale problems, where efficient methods are necessary with today’s computational resources. The outcome of this work was also the creation of several freely available Python modules for Uncertainty Quantification, which are listed and described in the appendix....
To the problem of reinforced concrete reactor vessel design and calculation

International Nuclear Information System (INIS)

Kirillov, A.P.; Artem'ev, V.P.; Bogopol'skij, V.G.; Nikolaev, Yu.B.; Paushkin, A.G.

1980-01-01

Modern methods for calculating reactor vessels of prestressed reinforced concrete are analyzed. It is shown that during the stage of technical and economical substantiation of reactor vessel structure for determining its stressed-deformed state engineering methods of calculation must be used, in particular, fragmentation method, method of rings and plates, and during the stages of contract and detail designs - method of finite elements and dynamic relaxation method. It is concluded that when solving cyclic symmetrical problems as well as asymmetrical problems, calculational algorithms for axis-symmetrical distributions of stresses in the vessel with provision for elastic properties of structural material may be used
Dam construction as an engineering solution for water supply problem : environmental thrusts

Energy Technology Data Exchange (ETDEWEB)

Hosseini, A.H. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

2004-09-01

Water supply management and the potential impacts associated with engineering practices in water supply systems were examined. Global aspects of increasing water demand were presented and compared with populations, urbanization and water demand. Engineering practices in waterworks developments such as dam construction, river intakes, infiltration galleries, wells, boreholes and adits were also discussed. Construction of large dams and the problems associated with damming the rivers were studied as large dams generally have substantial impacts on rivers, watersheds and aquatic ecosystems, leading to the irreversible loss of species populations and ecosystems. These problems include negative impacts on the terrestrial ecosystem, greenhouse gas emissions from reservoirs due to decaying vegetation and carbon inflows from the catchment, changes in flow regimes, trapping of sediments and nutrients behind a dam, blocking migration of aquatic organisms, as well as negative impacts on flood plain ecosystems and fisheries. In addition, a case study, on the environmental impacts associated with damming in Three Gorges Valley in China was presented. 9 refs., 8 figs.
Profiles of Observed Infant Anger Predict Preschool Behavior Problems: Moderation by Life Stress

Science.gov (United States)

Brooker, Rebecca J.; Buss, Kristin A.; Lemery-Chalfant, Kathryn; Aksan, Nazan; Davidson, Richard J.; Goldsmith, H. Hill

2014-01-01

Using both traditional composites and novel profiles of anger, we examined associations between infant anger and preschool behavior problems in a large, longitudinal data set (N = 966). We also tested the role of life stress as a moderator of the link between early anger and the development of behavior problems. Although traditional measures of…
A Typology of Engineering Designs in Problem-Based Projects

DEFF Research Database (Denmark)

Larsen, Samuel Brüning; Bigum, Per Valentin

include a set of general characteristics of great engineering solutions and a typology of three solution archetypes. The study labels these archetypes as 1) the adapted solution, 2) the “either/or”-solution, and 3) the multiple-elements solution. For each archetype, the paper specifies the corresponding...... class of problems that the archetype can logically address. In addition, the paper delineates (1) how each archetype relates to a project’s analysis and (2) how each archetype is evaluated, implemented and operated. The typology aids both students and project supervisors in conducting reports...
Residual stresses and stress corrosion effects in cast steel nuclear waste overpacks

International Nuclear Information System (INIS)

Attinger, R.O.; Mercier, O.; Knecht, B.; Rosselet, A.; Simpson, J.P.

1991-01-01

In the concepts for final disposal of high-level radioactive waste in Switzerland, one engineered barrier consists of an overpack made out of cast steel GS-40. Whenever tensile stresses are expected in the overpack, the issue of stress corrosion cracking must be expected. A low-strength steel was chosen to minimize potential problems associated with stress corrosion cracking. A series of measurements on stress corrosion cracking under the conditions as expected in the repository confirmed that the corrosion allowance of 50 mm used for the design of the reference overpack is sufficient over the 1000 years design lifetime. Tensile stresses are introduced by the welding process when the overpack is closed. For a multipass welding, the evolution of deformations, strains and stresses were determined in a finite-element calculation. Assuming an elastic-plastic material behavior without creep, the residual stresses are high; considering creep would reduce them. A series of creep tests revealed that the initial creep rate is important for cast steel already at 400deg C. (orig.)
Some current engineering topics in nuclear power plant components

International Nuclear Information System (INIS)

Amana, M.

1977-01-01

An analysis based on the principle of fracture mechanics, is presented for several engineering problems occuring in nuclear power plant components. The specific problems covered are: underclad cracking; stress corrosion cracking; cracks in HAZ of nozzle weld; feedwater nozzle corner crack; shift of transition temperature due to neutron irradiation; LWR local-ECC thermal shock experiment; and design and material selection of RPV in terms of fracture mechanics. (B.R.H.)
Economic Deprivation and Its Effects on Childhood Conduct Problems: The Mediating Role of Family Stress and Investment Factors

Directory of Open Access Journals (Sweden)

Edward M. Sosu

2017-09-01

Full Text Available This study investigated the mechanisms by which experiences of poverty influence the trajectory of conduct problems among preschool children. Drawing on two theoretical perspectives, we focused on family stress (stress and harsh discipline and investment variables (educational investment, nutrition, and cognitive ability as key mediators. Structural equation modeling techniques with prospective longitudinal data from the Growing Up in Scotland survey (N = 3,375 were used. Economic deprivation measured around the first birthday of the sample children had both direct and indirect effects on conduct problems across time (ages 4, 5, and 6. In line with the family stress hypothesis, higher levels of childhood poverty predicted conduct problems across time through increased parental stress and punitive discipline. Consistent with the investment model, childhood deprivation was associated with higher levels of conduct problems via educational investment and cognitive ability. The study extends previous knowledge on the mechanisms of this effect by demonstrating that cognitive ability is a key mediator between poverty and the trajectory of childhood conduct problems. This suggests that interventions aimed at reducing child conduct problems should be expanded to include factors that compromise parenting as well as improve child cognitive ability.
Job dissatisfaction as a contributor to stress-related mental health problems among Japanese civil servants.

Science.gov (United States)

Tatsuse, Takashi; Sekine, Michikazu

2013-01-01

Although studies on the association of job dissatisfaction with mental health have been conducted in the past, few studies have dealt with the complicated links connecting job stress, job dissatisfaction, and stress-related illness. This study seeks to determine how job dissatisfaction is linked to common mental health issues. This study surveyed 3,172 civil servants (2,233 men and 939 women) in 1998, taking poor mental functioning, fatigue, and sleep disturbance as stress-related mental health problems. We examine how psychosocial risk factors at work and job dissatisfaction are associated independently with poor mental functioning, fatigue, and sleep disturbance after adjustment for other known risk factors, and how job dissatisfaction contributes to change in the degree of association between psychosocial risk factors at work and mental health problems. In general, psychosocial risk factors were independently associated with mental health problems. When adjusted for job dissatisfaction, not only was job satisfaction independently associated with mental health problems but it was also found that the association of psychosocial risk factors with mental health problems declined. Our results suggest that, although longitudinal research is necessary, attitudes toward satisfaction at work can potentially decrease the negative effects of psychosocial risk factors at work on mental health.
SC: A NOVEL FUZZY CRITERION FOR SOLVING ENGINEERING AND CONSTRAINED OPTIMIZATION PROBLEMS

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Sergio G. De los Cobos Silva

2017-04-01

Full Text Available In this paper a novel fuzzy convergence system (SC and its fundamentals are presented. The model was implemented on a monoobjetive PSO algorithm with three phases: 1 Stabilization, 2 generation and breadth-first search, and 3 generation and depth-first. The system SC-PSO-3P was tested with several benchmark engineering problems and with several CEC2006 problems. The computing experience and comparison with previously reported results is presented. In some cases the results reported in the literature are improved.
Use of fracture mechanics in engineering problems

Energy Technology Data Exchange (ETDEWEB)

Carter, C S

1965-02-26

If an engineering material containing a crack is subjected to a slowly increasing load, applied so that the crack tends to open, a small zone of plastic yielding develops at the crack tip. This zone increases in size with increasing load, and has the effect of resisting the tendency of the crack to extend. The basic concepts of fracture mechanics are outlined and the significance of crack toughness as measured by KDcU and KD1cU which relate the applied stress and crack size for unstable fracture prior to general yielding is discussed. The methods available for crack-toughness evaluation are indicated, and the mathematical expressions describing KDcU and KD1cU for a variety of geometrical situations are quoted. This approach to the design of fracture- resistant structures has been used in a number of fields in the U.S. and could be of value to the British steam turbine, aerospace, and pressure-vessel industries for design, inspection, and material selection. (64 refs.)
Activist engineering: changing engineering practice by deploying praxis.

Science.gov (United States)

Karwat, Darshan M A; Eagle, Walter E; Wooldridge, Margaret S; Princen, Thomas E

2015-02-01

In this paper, we reflect on current notions of engineering practice by examining some of the motives for engineered solutions to the problem of climate change. We draw on fields such as science and technology studies, the philosophy of technology, and environmental ethics to highlight how dominant notions of apoliticism and ahistoricity are ingrained in contemporary engineering practice. We argue that a solely technological response to climate change does not question the social, political, and cultural tenet of infinite material growth, one of the root causes of climate change. In response to the contemporary engineering practice, we define an activist engineer as someone who not only can provide specific engineered solutions, but who also steps back from their work and tackles the question, What is the real problem and does this problem "require" an engineering intervention? Solving complex problems like climate change requires radical cultural change, and a significant obstacle is educating engineers about how to conceive of and create "authentic alternatives," that is, solutions that differ from the paradigm of "technologically improving" our way out of problems. As a means to realize radically new solutions, we investigate how engineers might (re)deploy the concept of praxis, which raises awareness in engineers of the inherent politics of technological design. Praxis empowers engineers with a more comprehensive understanding of problems, and thus transforms technologies, when appropriate, into more socially just and ecologically sensitive interventions. Most importantly, praxis also raises a radical alternative rarely considered-not "engineering a solution." Activist engineering offers a contrasting method to contemporary engineering practice and leads toward social justice and ecological protection through problem solving by asking not, How will we technologize our way out of the problems we face? but instead, What really needs to be done?
Prevalence of menstrual problems and their association with psychological stress in young female students studying health sciences

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Nazish Rafique

2018-01-01

Full Text Available Objectives: To identify the prevalence of various menstrual problems in young females studying health sciences and to identify their association with academic stress. Methods: This was a cross-sectional study, conducted in the health colleges of Immam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia between February 2015 and February 2016. Seven hundred and thirty-eight female students aged 18-25 years anonymously completed menstrual problem identification and perceived stress scale questionnaire. The data was analyzed using the Statistical Package for Social Sciences version 16.0. Results: Ninety-one percent of the students were suffering from some kind of menstrual problem. The different menstrual problems reported, and their incidences included irregular menstruation (27%, abnormal vaginal bleeding (9.3%, amenorrhea (9.2%, menorrhagia (3.4%, dysmenorrhea (89.7%, and premenstrual symptoms (46.7%. High perceived stress (HPS was identified in 39% of the students. A significant positive correlation was found between HPS and menstrual problems. Students with HPS had 4 times, 2 times, and 2.8 times increased odds ratio for experiencing amenorrhea, dysmenorrhea, and premenstrual syndrome (p less than 0.05. Conclusion: The most prevalent menstrual problems (dysmenorrhea and premenstrual symptoms in the target population were strongly associated with stress. Therefore, it is recommended that health science students should be provided with early psychological and gynecological counselling to prevent future complications.
Mindfulness-based stress reduction for parents of young children with developmental delays: implications for parental mental health and child behavior problems.

Science.gov (United States)

Neece, Cameron L

2014-03-01

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

CERN Document Server

Kitahara, M

1985-01-01

The boundary integral equation (BIE) method has been used more and more in the last 20 years for solving various engineering problems. It has important advantages over other techniques for numerical treatment of a wide class of boundary value problems and is now regarded as an indispensable tool for potential problems, electromagnetism problems, heat transfer, fluid flow, elastostatics, stress concentration and fracture problems, geomechanical problems, and steady-state and transient electrodynamics.In this book, the author gives a complete, thorough and detailed survey of the method. It pro
Developing Creativity and Problem-Solving Skills of Engineering Students: A Comparison of Web- and Pen-and-Paper-Based Approaches

Science.gov (United States)

Valentine, Andrew; Belski, Iouri; Hamilton, Margaret

2017-01-01

Problem-solving is a key engineering skill, yet is an area in which engineering graduates underperform. This paper investigates the potential of using web-based tools to teach students problem-solving techniques without the need to make use of class time. An idea generation experiment involving 90 students was designed. Students were surveyed…
Theoretical and experimental investigations concerning the problem of quasi-static crack propagation in two-component materials subject to residual stresses

International Nuclear Information System (INIS)

Braun, H.P.

1979-01-01

With the aim of obtaining microstructural information of multi-component materials fracture-mechanical calculations on continuum-mechanical models of fiber composites were performed. There were ideal sections of material permitting the formulation of suitable mixed boundary value problems of static thermoelasticity whose solutions could be obtained by means of appropriate numerical methods from continuum mechanics. As model loads exclusively thermally induced residual stresses were assumed, being of special interest because of the thermomechanically inhomogeneous structure of composite materials on one hand and having got decisive significance for a number of important areas of application as e.g. aero-space industry, reactor technology and chemical apparatus engineering on the other. The results evaluated numerically are exemplarily examined by means of photoelasticity. (orig./IHOE) [de
Development Of Entrepreneur Learning Model Based On Problem Based Learning To Increase Competency Independence And Creativity Students Of Industrial Engineering

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Leola Dewiyani

2017-10-01

Full Text Available Currently it is undeniable that the competition to get a job is very tight and of course universities have an important role in printing human resources that can compete globally not least with the Department of Industrial Engineering Faculty of Engineering Muhammadiyah University of Jakarta FT UMJ. Problems that occur is based on the analysis obtained from the track record of graduates researchers found that 60 percent of students of Industrial Engineering FT UMJ work not in accordance with the level of education owned so financially their income is still below the standard. This study aims to improve the competence of students of Industrial Engineering Department FT UMJ in entrepreneurship courses especially through the development of Problem Based Learning based learning model. Specific targets of this research were conducted with the aim to identify and analyze the need to implement learning model based on Problem Based Learning Entrepreneurship and to design and develop the model of entrepreneurship based on Problem Based Learning to improve the competence independence and creativity of Industrial Engineering students of FT UMJ in Entrepreneurship course. To achieve the above objectives this research uses research and development R amp D method. The product produced in this research is the detail of learning model of entrepreneurial model based on Problem Based Learning entrepreneurship model based on Problem Based Learning and international journals
The stress-response dampening hypothesis: how self-esteem and stress act as mechanisms between negative parental bonds and alcohol-related problems in emerging adulthood.

Science.gov (United States)

Backer-Fulghum, Lindsey M; Patock-Peckham, Julie A; King, Kevin M; Roufa, Lindsay; Hagen, Leslie

2012-04-01

The stress dampening model (Marlatt, 1987; Sayette, 1993; Sher, 1987) suggests certain individuals may use alcohol to escape from their negative life experiences. Pathological reasons for drinking (e.g., using alcohol as a means to cope) reflect the degree to which individuals are motivated to use alcohol in order to dampen or alleviate the stress they are experiencing (Johnson, Schwitters, Wilson, Nagoshi, & McClearn, 1985). Direct and mediational links among parental bonds (rejection, care, overprotection, autonomy, and neglect), self-esteem, stress, pathological reasons for drinking, and alcohol-related problems were explored. A Structural Equation Model with (405 students; 164 women, 241 men) college students was examined. Three path mediational analyses revealed several mediated pathways. Greater feelings of perceived father/mother neglectfulness (i.e., offspring feeling parents do not show up for them) were indirectly linked to more alcohol-related problems (e.g., indicative of alcohol use or dependence in emerging adulthood) through increased stress and pathological reasons for drinking. Furthermore, higher levels of father rejection (i.e., perception of feeling unwanted) were indirectly linked to more pathological reasons for drinking through low self-esteem and increased stress. However, greater feelings of mother care (affectionate and attentive) were indirectly linked to fewer pathological reasons for drinking through higher self-esteem and lower levels of stress. Moreover, high self-esteem was found to be indirectly linked to fewer alcohol-related problems through decreased stress and pathological reasons for drinking. These findings suggest several specific pathways for using alcohol to self-medicate (i.e., consume alcohol for a specific purpose) or dampen feelings of stress. Copyright © 2011 Elsevier Ltd. All rights reserved.
Physically - engineering problems of the Salaspils Nuclear reactor: Solutions and their topicality

International Nuclear Information System (INIS)

Mozgirs, Z.V.

2005-01-01

The paper generalizes technical solutions of physically-engineering problems of the Salaspils nuclear research reactor, experience of its modernization and exploitation. New equipment and the related technical solutions have been tested at the Salaspils reactor during its operation time and are now recommended for further use at nuclear reactors. (author)

The Problem-Solving Process in Physics as Observed When Engineering Students at University Level Work in Groups

Science.gov (United States)

Gustafsson, Peter; Jonsson, Gunnar; Enghag, Margareta

2015-01-01

The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit…
Stress and coping mediate relationships between contingent and global self-esteem and alcohol-related problems among college drinkers.

Science.gov (United States)

Tomaka, Joe; Morales-Monks, Stormy; Shamaley, Angelee Gigi

2013-08-01

This study examined the hypotheses that contingent self-esteem would be positively associated with alcohol-related problems and that global self-esteem would be negatively associated with such problems. It also examined the hypothesis that high stress and maladaptive coping would mediate these relationships. A sample of college students (n = 399) who were predominantly Hispanic (89%) completed measures of global and contingent self-esteem; stress and coping; and alcohol-related problems. Correlational and latent variable analyses indicated that contingent self-esteem positively related to alcohol-related problems, with maladaptive coping mediating this relationship. In contrast, global self-esteem negatively related to such problems, a relationship that was also mediated by maladaptive coping and stress. Overall, the results highlight the potentially harmful consequences of contingent self-worth and the adaptive nature of non-contingent self-esteem. They also demonstrate the important role that coping plays in mediating self-esteem's associations with alcohol-related problems. Copyright © 2012 John Wiley & Sons, Ltd.
Relative deprivation in the Nordic countries-child mental health problems in relation to parental financial stress

DEFF Research Database (Denmark)

Gunnarsdóttir, Hrafnhildur; Hensing, Gunnel; Povlsen, Lene

2016-01-01

BACKGROUND: The Nordic welfare system has been acknowledged as favourable for children, successfully contributing to low child mortality and poverty rates. Nevertheless, mental health problems among children and adolescents are common and the economic situation of the family has been highlighted...... as an important determinant. In spite of similar social, political and cultural structures, the Nordic countries differ; Iceland was most affected by the global financial crisis in 2008. The aim of this study was to examine potential differences in parental financial stress and the associations to child mental...... to measure mental health problems. RESULTS: In Iceland, 47.7% of the parents reported financial stress while ≤20% did so in the other countries except for Finland (33.5%). However, in case of parental financial stress the OR of mental health problems comparing children to parents with and without financial...
Deformation stresses and mechanical behaviour of engineered barriers in the repository environment

International Nuclear Information System (INIS)

Ipatti, A.; Majamaeki, O.

1991-12-01

The report surveys functioning of the engineered barriers in the Loviisa repository under deformation stresses of the solidification product and the concrete filling material. The survey is based on the latest estimates of the waste amounts and the corresponding repository plans, and on solidification product compositions and properties. The IVOFEM and NASTRAN software was used in the structural analyses. The materials were supposed to be homogeneous and linearly elastic and dislocations small. Accordingly, the design loads were chosen conservatively so that the impacts of deformation stresses are sufficiently overestimated. A reinforced concrete container lined with cellular plastic remains a watertight structure, meeting the requirements set in view of expansion of a solidification product. In view of the stresses, the decisive time is the intermediate storage stage. The greatest stresses are found in junctions between the container wall and the bottom and cover. The concrete filling between the waste packages cannot resist the drying shrinkage and wetting expansion stresses without cracking. Concrete walls of the repository can withstand the stress caused by wetting expansion of the waste packages only when strongly reinforced. However, the forces against the walls are so big that if cracks in the concrete walls are desired to be restricted, due to reinforcement steel corrosion or wall tightness, the present type of filling material between the waste packages is not necessarily technically the best alternative
Training of innovative engineers for problems of modernization of a domestic production

Directory of Open Access Journals (Sweden)

Brusakova I.

2017-01-01

Full Text Available The actual problem of training of innovative managers for problems of modernization of a domestic production is considered in research. Practice of application of innovative engineering in the sphere of modernization of industrial productions is studied. The perspective of an integrated approach to management of innovative processes is investigated, including competence-based approach to training of innovative managers and modern instruments of management of finance innovative business - processes. Authors offered new approaches to formation of innovative capacity of the domestic industrial enterprises. Different ways of innovation creation are discussing.
The Relationship between Parenting Stress, Parental Intelligence and Child Behavior Problems in a Study of Korean Preschool Mothers

Science.gov (United States)

Kwon, Jeong Yoon

2007-01-01

The current study examined the relationship between Korean mothers' parenting stress and parental intelligence, and child behavior problems as well as the mediation effects of parental intelligence, which tested the association between parenting stress and child behavior problems. A sample of 436 typically developing children and their mothers…
Applied thermodynamics for engineering technologies. 4th edition

International Nuclear Information System (INIS)

Eastop, T.D.; Mc Conkey, A.

1986-01-01

This book presents a complete introduction to the fundamentals of the theory and application of thermodynamics. Revisions include a new chapter on the sources, uses and management of energy as well as major updating of the chapters on internal combustion engines and psychometry. It features new sections on extended surfaces, two-dimensional and transient conduction using finite difference methods, and the NTU method for heat exchanger design. It also stresses the application of theory to real situations and applies principles to practical engineering problems
Hybrid-finite-element analysis of some nonlinear and 3-dimensional problems of engineering fracture mechanics

Science.gov (United States)

Atluri, S. N.; Nakagaki, M.; Kathiresan, K.

1980-01-01

In this paper, efficient numerical methods for the analysis of crack-closure effects on fatigue-crack-growth-rates, in plane stress situations, and for the solution of stress-intensity factors for arbitrary shaped surface flaws in pressure vessels, are presented. For the former problem, an elastic-plastic finite element procedure valid for the case of finite deformation gradients is developed and crack growth is simulated by the translation of near-crack-tip elements with embedded plastic singularities. For the latter problem, an embedded-elastic-singularity hybrid finite element method, which leads to a direct evaluation of K-factors, is employed.
Distribution of Side Abutment Stress in Roadway Subjected to Dynamic Pressure and Its Engineering Application

Directory of Open Access Journals (Sweden)

Yao Qiangling

2015-01-01

Full Text Available The borehole stress-meter was employed in this study to investigate the distribution of the side abutment stress in roadway subjected to dynamic pressure. The results demonstrate that the side abutment stress of the mining roadway reaches a peak value when the distance to the gob is 8 m and the distribution curve of the side abutment stress can be divided into three zones: stress rising zone, stress stabilizing zone, and stress decreasing zone. Further numerical investigation was carried out to study the effect of the coal mass strength, coal seam depth, immediate roof strength, and thickness on the distribution of the side abutment stress. Based on the research results, we determined the reasonable position of the mining roadway and the optimal width of the barrier pillar. The engineering application demonstrates that the retention of the barrier pillar with a width of 5 m along the gob as the haulage roadway for the next panel is feasible, which delivers favorable technological and economic benefits.
Hybrid intelligent optimization methods for engineering problems

Science.gov (United States)

Pehlivanoglu, Yasin Volkan

The purpose of optimization is to obtain the best solution under certain conditions. There are numerous optimization methods because different problems need different solution methodologies; therefore, it is difficult to construct patterns. Also mathematical modeling of a natural phenomenon is almost based on differentials. Differential equations are constructed with relative increments among the factors related to yield. Therefore, the gradients of these increments are essential to search the yield space. However, the landscape of yield is not a simple one and mostly multi-modal. Another issue is differentiability. Engineering design problems are usually nonlinear and they sometimes exhibit discontinuous derivatives for the objective and constraint functions. Due to these difficulties, non-gradient-based algorithms have become more popular in recent decades. Genetic algorithms (GA) and particle swarm optimization (PSO) algorithms are popular, non-gradient based algorithms. Both are population-based search algorithms and have multiple points for initiation. A significant difference from a gradient-based method is the nature of the search methodologies. For example, randomness is essential for the search in GA or PSO. Hence, they are also called stochastic optimization methods. These algorithms are simple, robust, and have high fidelity. However, they suffer from similar defects, such as, premature convergence, less accuracy, or large computational time. The premature convergence is sometimes inevitable due to the lack of diversity. As the generations of particles or individuals in the population evolve, they may lose their diversity and become similar to each other. To overcome this issue, we studied the diversity concept in GA and PSO algorithms. Diversity is essential for a healthy search, and mutations are the basic operators to provide the necessary variety within a population. After having a close scrutiny of the diversity concept based on qualification and
Direct, CMOS In-Line Process Flow Compatible, Sub 100 °C Cu-Cu Thermocompression Bonding Using Stress Engineering

Science.gov (United States)

Panigrahi, Asisa Kumar; Ghosh, Tamal; Kumar, C. Hemanth; Singh, Shiv Govind; Vanjari, Siva Rama Krishna

2018-03-01

Diffusion of atoms across the boundary between two bonding layers is the key for achieving excellent thermocompression Wafer on Wafer bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu-Cu bonding which is devoid of Cu surface treatment prior to bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality thermocompression bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10-8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu-Cu bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu-Cu bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable bonding without electrical performance degradation.
Direct, CMOS In-Line Process Flow Compatible, Sub 100 °C Cu-Cu Thermocompression Bonding Using Stress Engineering

Science.gov (United States)

Panigrahi, Asisa Kumar; Ghosh, Tamal; Kumar, C. Hemanth; Singh, Shiv Govind; Vanjari, Siva Rama Krishna

2018-05-01

Diffusion of atoms across the boundary between two bonding layers is the key for achieving excellent thermocompression Wafer on Wafer bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu-Cu bonding which is devoid of Cu surface treatment prior to bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality thermocompression bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10-8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu-Cu bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu-Cu bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable bonding without electrical performance degradation.
Stone cladding engineering

CERN Document Server

Sousa Camposinhos, Rui de

2014-01-01

This volume presents new methodologies for the design of dimension stone based on the concepts of structural design while preserving the excellence of stonemasonry practice in façade engineering. Straightforward formulae are provided for computing action on cladding, with special emphasis on the effect of seismic forces, including an extensive general methodology applied to non-structural elements. Based on the Load and Resistance Factor Design Format (LRDF), minimum slab thickness formulae are presented that take into consideration stress concentrations analysis based on the Finite Element Method (FEM) for the most commonly used modern anchorage systems. Calculation examples allow designers to solve several anchorage engineering problems in a detailed and objective manner, underlining the key parameters. The design of the anchorage metal parts, either in stainless steel or aluminum, is also presented.
Plotting and Determination of Nominal Stresses in the Сrankshaft Components of V Configuration Engine with Offset Rod Bearing Journals

Directory of Open Access Journals (Sweden)

M. Yu. Mikhailov

2017-01-01

Full Text Available Currently, a great number of large vehicle engines, especially diesel ones, have a V-shaped configuration layout. For six-cylinder and eight-cylinder V-engines, to simplify a processing technology of the block-crankcases, in the section manufacturers often use the 90° angle, which is the most prevalent angle for the V8 engine. However, in this case, an even firing cycle in the cylinders is not provided for the V6 layout. This leads to significant vibrations, especially at idle and requires for a more massive flywheel.Designers face the challenge to provide the even firing cycle in the cylinders. To solve this problem are often used the crankshaft designs, which have the offset rod journals. However, it leads to the manufacturing complexity of the shaft, and also to the need to use the special methods of calculation.There are no direct calculation methods for the crankshafts of this design. The paper proposes a technique to define the nominal stresses in the crankshaft of this design. To consider the shaft is used a split-type design. The paper presents a schematic diagram of the crankshaft loading, and on its basis describes equations of the moments for each section. A special attention is drawn to the new constructive element, i.e. an intermediate cheek. For clarity, the diagrams of moments in two mutually perpendicular planes are built. It is worth noting that the paper also proposes a technique from transition from the global to the local coordinate system when considering the moments in the crankshaft elements.Further, there are the appropriate expressions to determine the nominal stresses. This is one of the main desired values in calculating the crankshaft endurance. The developed technique in the particular case allows the calculation of crankshaft engine models that can be subsumed under the advantages.In the future the proposed technique is expected to be a basis for creating a software complex. The complex objective is expected to be
Large-Scale Parallel Finite Element Analysis of the Stress Singular Problems

International Nuclear Information System (INIS)

Noriyuki Kushida; Hiroshi Okuda; Genki Yagawa

2002-01-01

In this paper, the convergence behavior of large-scale parallel finite element method for the stress singular problems was investigated. The convergence behavior of iterative solvers depends on the efficiency of the pre-conditioners. However, efficiency of pre-conditioners may be influenced by the domain decomposition that is necessary for parallel FEM. In this study the following results were obtained: Conjugate gradient method without preconditioning and the diagonal scaling preconditioned conjugate gradient method were not influenced by the domain decomposition as expected. symmetric successive over relaxation method preconditioned conjugate gradient method converged 6% faster as maximum if the stress singular area was contained in one sub-domain. (authors)
Research on Life Science and Life Support Engineering Problems of Manned Deep Space Exploration Mission

Science.gov (United States)

Qi, Bin; Guo, Linli; Zhang, Zhixian

2016-07-01

Space life science and life support engineering are prominent problems in manned deep space exploration mission. Some typical problems are discussed in this paper, including long-term life support problem, physiological effect and defense of varying extraterrestrial environment. The causes of these problems are developed for these problems. To solve these problems, research on space life science and space medical-engineering should be conducted. In the aspect of space life science, the study of space gravity biology should focus on character of physiological effect in long term zero gravity, co-regulation of physiological systems, impact on stem cells in space, etc. The study of space radiation biology should focus on target effect and non-target effect of radiation, carcinogenicity of radiation, spread of radiation damage in life system, etc. The study of basic biology of space life support system should focus on theoretical basis and simulating mode of constructing the life support system, filtration and combination of species, regulation and optimization method of life support system, etc. In the aspect of space medical-engineering, the study of bio-regenerative life support technology should focus on plants cultivation technology, animal-protein production technology, waste treatment technology, etc. The study of varying gravity defense technology should focus on biological and medical measures to defend varying gravity effect, generation and evaluation of artificial gravity, etc. The study of extraterrestrial environment defense technology should focus on risk evaluation of radiation, monitoring and defending of radiation, compound prevention and removal technology of dust, etc. At last, a case of manned lunar base is analyzed, in which the effective schemes of life support system, defense of varying gravity, defense of extraterrestrial environment are advanced respectively. The points in this paper can be used as references for intensive study on key
Children's Exposure to Violence: The Underlying Effect of Posttraumatic Stress Symptoms on Behavior Problems.

Science.gov (United States)

Yoon, Susan; Steigerwald, Stacey; Holmes, Megan R; Perzynski, Adam T

2016-02-01

In this study we investigated whether witnessing violence and violence victimization were associated with children's internalizing and externalizing behavior problems and examined the mediating role of posttraumatic stress (PTS) symptoms in these relationships. Secondary data analysis was conducted using 3 waves of data from the National Survey of Child and Adolescent Well-Being. Path analyses were conducted to test direct and indirect effects of violence exposure on behavior problems, using 2,064 children (ages 8-15 years) reported to Child Protective Services for maltreatment. Being a victim of violence in the home was directly associated with more internalizing (β = .06, p = .007) and externalizing behavior problems (β = .07, p = .002), whereas witnessing violence was not directly related to either internalizing (β = .04, p = .056) or externalizing behavior problems (β = .03, p = .130). PTS symptoms mediated the effects of witnessing violence and violence victimization on internalizing behavior problems (β = .02, p = .002). Our findings suggest that PTS symptoms may be a mechanism underlying the association between violence exposure and internalizing behavior problems (R(2) = .23), underscoring the potential importance of assessing PTS symptoms and providing targeted trauma-focused interventions for children exposed to violence at home. Copyright © 2016 International Society for Traumatic Stress Studies.
Understanding ill-structured engineering ethics problems through a collaborative learning and argument visualization approach.

Science.gov (United States)

Hoffmann, Michael; Borenstein, Jason

2014-03-01

As a committee of the National Academy of Engineering recognized, ethics education should foster the ability of students to analyze complex decision situations and ill-structured problems. Building on the NAE's insights, we report about an innovative teaching approach that has two main features: first, it places the emphasis on deliberation and on self-directed, problem-based learning in small groups of students; and second, it focuses on understanding ill-structured problems. The first innovation is motivated by an abundance of scholarly research that supports the value of deliberative learning practices. The second results from a critique of the traditional case-study approach in engineering ethics. A key problem with standard cases is that they are usually described in such a fashion that renders the ethical problem as being too obvious and simplistic. The practitioner, by contrast, may face problems that are ill-structured. In the collaborative learning environment described here, groups of students use interactive and web-based argument visualization software called "AGORA-net: Participate - Deliberate!". The function of the software is to structure communication and problem solving in small groups. Students are confronted with the task of identifying possible stakeholder positions and reconstructing their legitimacy by constructing justifications for these positions in the form of graphically represented argument maps. The argument maps are then presented in class so that these stakeholder positions and their respective justifications become visible and can be brought into a reasoned dialogue. Argument mapping provides an opportunity for students to collaborate in teams and to develop critical thinking and argumentation skills.
Approximate stresses in 2-D flat elastic contact fretting problems

Science.gov (United States)

Urban, Michael Rene

Fatigue results from the cyclic loading of a solid body. If the body subject to fatigue is in contact with another body and relative sliding motion occurs between these two bodies, then rubbing surface damage can accelerate fatigue failure. The acceleration of fatigue failure is especially important if the relative motion between the two bodies results in surface damage without excessive surface removal via wear. The situation just described is referred to as fretting fatigue. Understanding of fretting fatigue is greatly enhanced if the stress state associated with fretting can be characterized. For Hertzian contact, this can readily be done. Unfortunately, simple stress formulae are not available for flat body contact. The primary result of the present research is the development of a new, reasonably accurate, approximate closed form expression for 2-dimensional contact stresses which has been verified using finite element modeling. This expression is also combined with fracture mechanics to provide a simple method of determining when a crack is long enough to no longer be affected by the contact stress field. Lower bounds on fatigue life can then easily be calculated using fracture mechanics. This closed form expression can also be used to calculate crack propagation within the contact stress field. The problem of determining the cycles required to generate an initial crack and what to choose as an initial crack size is unresolved as it is in non-fretting fatigue.
Modeling and simulation of different and representative engineering problems using Network Simulation Method.

Science.gov (United States)

Sánchez-Pérez, J F; Marín, F; Morales, J L; Cánovas, M; Alhama, F

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model.

Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

Science.gov (United States)

CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...
Effect of heat stress on contractility of tissue-engineered artificial skeletal muscle.

Science.gov (United States)

Takagi, Shunya; Nakamura, Tomohiro; Fujisato, Toshia

2018-01-23

The effects of heat stress on tissue like skeletal muscle have been widely studied. However, the mechanism responsible for the effect of heat stress is still unclear. A useful experimental tissue model is necessary because muscle function in cell culture may differ from native muscle and measuring its contractility is difficult. We previously reported three-dimensional tissue-engineered artificial skeletal muscle (TEM) that can be easily set in a measurement apparatus for quantitative evaluation of contractility. We have now applied TEM to the investigation of heat stress. We analyzed contractility immediately after thermal exposure at 39 °C for 24 or 48 h to evaluate the acute effects and after thermal exposure followed by normal culture to evaluate the aftereffects. Peak twitch contractile force and time-to-peak twitch were used as contractile parameters. Heat stress increased the TCF in the early stage (1 week) after normal culture; the TCF decreased temporarily in the middle to late stages (2-3 weeks). These results suggest that heat stress may affect both myoblast fusion and myotube differentiation in the early stage of TEM culture, but not myotube maturation in the late stage. The TCF increase rate with thermal exposure was significantly higher than that without thermal exposure. Although detailed analysis at the molecular level is necessary for further investigation, our artificial skeletal muscle may be a promising tool for heat stress investigation.
Stresses in Circular Plates with Rigid Elements

Science.gov (United States)

Velikanov, N. L.; Koryagin, S. I.; Sharkov, O. V.

2018-05-01

Calculations of residual stress fields are carried out by numerical and static methods, using the flat cross-section hypothesis. The failure of metal when exposed to residual stresses is, in most cases, brittle. The presence in the engineering structures of rigid elements often leads to the crack initiation and structure failure. This is due to the fact that rigid elements under the influence of external stresses are stress concentrators. In addition, if these elements are fixed by welding, the residual welding stresses can lead to an increase in stress concentration and, ultimately, to failure. The development of design schemes for such structures is a very urgent task for complex technical systems. To determine the stresses in a circular plate with a welded circular rigid insert under the influence of an external load, one can use the solution of the plane stress problem for annular plates in polar coordinates. The polar coordinates of the points are the polar radius and the polar angle, and the stress state is determined by normal radial stresses, tangential and shearing stresses. The use of the above mentioned design schemes, formulas, will allow more accurate determination of residual stresses in annular welded structures. This will help to establish the most likely directions of failure and take measures at the stages of designing, manufacturing and repairing engineering structures to prevent these failures. However, it must be taken into account that the external load, the presence of insulation can lead to a change in the residual stress field.
Parenting Stress and Child Behavior Problems among Clinic-Referred Youth: Cross-Cultural Differences across the US and Korea

Science.gov (United States)

Chung, Kyong-Mee; Ebesutani, Chad; Bang, Hye Min; Kim, Joohee; Chorpita, Bruce F.; Weisz, John R.; Suh, Dongsoo; Byun, Heejung

2013-01-01

Due to increased multiculturalism in the US and abroad, there is a need for increased understanding of the different ways in which parenting stress is related to child problems across cultures. In the present study, we investigated (a) differences in reported parenting stress and childhood problem behaviors across a Korean (n = 71) and US (n = 71)…
Oxygen sensor equipped engine operation on methanol/gasoline blends and phase separation problems

Energy Technology Data Exchange (ETDEWEB)

Last, A J; Lawson, A; Simmons, E W; Mackay, D; Tsang, M; Maund, G B

1980-01-01

A study was made to address problems related to Canadian utilization of methanol/gasoline blends. These problems are: (1) cold weather operation; (2) water sensitivity to phase separation in winter; (3) vehicle compatibility: fuel/air ratio control, flexibility for vehicle movement outside of areas where methanol might be available. Specifically, the operation of the HydroShear (an in-line hydraulic emulsifier) on the two separated phases of a methanol/gasoline/water blend was examined. Fuel maps, by engine dynamometer testing, were generated using methanol/gasoline blends containing 15% to 65% methanol. The capability of an oxygen sensor, located in the exhaust system, to control the fuel/air ratio was found to be adequate within the 15% to 65% methanol/gasoline blends. A fuel injected Volvo 244DL with lambda-sond emission control and a carburetted Chevrolet Monza with 3-way catalyst closed loop feedback emission control system were the two engines selected for this study.
Power Balancing of Inline Multicylinder Diesel Engine

Directory of Open Access Journals (Sweden)

S. H. Gawande

2012-01-01

Full Text Available In this work, a simplified methodology is presented for power balancing by reducing the amplitude of engine speed variation, which result in excessive torsional vibrations of the crankshaft of inline six-cylinder diesel engine. In modern fuel injection systems for reciprocating engines, nonuniform cylinder-wise torque contribution is a common problem due to nonuniform fuel supply due to a defect in fuel injection system, causing increased torsional vibration levels of the crankshaft and stress of mechanical parts. In this paper, a mathematical model for the required fuel adjustment by using amplitude of engine speed variation applied on the flywheel based on engine dynamics is suggested. From the found empirical relations and FFT analysis, the amplitude of engine speed variation (i.e., torsional vibration levels of the crankshaft of inline six-cylinder diesel engine genset can be reduced up to 55%. This proposed methodology is simulated by developing MATALB code for uniform and nonuniform working of direct injection diesel engine of SL90 type manufactured by Kirloskar Oil Engine Ltd., Pune, India.
Reducing Teacher Stress by Implementing Collaborative Problem Solving in a School Setting

Science.gov (United States)

Schaubman, Averi; Stetson, Erica; Plog, Amy

2011-01-01

Student behavior affects teacher stress levels and the student-teacher relationship. In this pilot study, teachers were trained in Collaborative Problem Solving (CPS), a cognitive-behavioral model that explains challenging behavior as the result of underlying deficits in the areas of flexibility/adaptability, frustration tolerance, and problem…
Stress-constrained truss topology optimization problems that can be solved by linear programming

DEFF Research Database (Denmark)

Stolpe, Mathias; Svanberg, Krister

2004-01-01

We consider the problem of simultaneously selecting the material and determining the area of each bar in a truss structure in such a way that the cost of the structure is minimized subject to stress constraints under a single load condition. We show that such problems can be solved by linear...... programming to give the global optimum, and that two different materials are always sufficient in an optimal structure....
Efficacy of an Online Resource for Teaching Interpersonal Problem Solving Skills to Women Graduate Students in Engineering

Science.gov (United States)

Bekki, Jennifer M.; Bernstein, Bianca; Fabert, Natalie; Gildar, Natalie; Way, Amy

2014-01-01

Interpersonal problem solving skills allow engineers to prevent interpersonal difficulties more effectively and to manage conflict, both of which are critical to successful participation on teams. This research provides evidence that the "Career"WISE online learning environment can improve those skills among women in engineering graduate…
Applications of artificial intelligence in engineering problems

Energy Technology Data Exchange (ETDEWEB)

Sriram, D; Adey, R

1986-01-01

This book presents the papers given at a conference on the use of artificial intelligence in engineering. Topics considered at the conference included Prolog logic, expert systems, knowledge representation and acquisition, knowledge bases, machine learning, robotics, least-square algorithms, vision systems for robots, natural language, probability, mechanical engineering, civil engineering, and electrical engineering.
[Executive functions and stressful characteristics of children with attention-deficit hyperactivity disorder: influence on behavioral problems during adolescence].

Science.gov (United States)

Colomer-Diago, Carla; Miranda-Casas, Ana; Herdoiza-Arroyo, Paulina; Presentación-Herrero, M Jesús

2012-02-29

The identification of possible factors that are influencing the course of attention-deficit hyperactivity disorder (ADHD) will allow the development of more effective early intervention strategies. AIMS. This research, which used a longitudinal and correlational design, set out to examine the temporal consistency of the primary symptoms and ADHD associated problems. In addition, the relationships and predictive power of working memory, inhibition and stressful characteristics of children with ADHD on the disorder symptoms and behavioral problems in adolescence was analyzed. This study included 65 families with children diagnosed with ADHD. In phase 1 children performed verbal working memory, visuo-spatial and inhibition tests, and information from parents about stressful characteristics of children was collected. In phase 1 and in the follow-up phase, which took place three years later, parents and teachers reported on the primary symptoms of ADHD and behavioral problems. Inattention symptoms as well as most behavioral problems were stable over time, while hyperactivity/impulsivity symptoms decreased. Moreover, neither working memory nor inhibition showed power to predict the central manifestations of ADHD or behavioral problems, while stressful characteristics of demandingness, low adaptability and negative mood had a moderate predictive capacity. These results confirm the role of stressful child characteristics as a risk factor in the course of ADHD.
Overhanging Features and the SLM/DMLS Residual Stresses Problem: Review and Future Research Need

Directory of Open Access Journals (Sweden)

Albert E. Patterson

2017-04-01

Full Text Available A useful and increasingly common additive manufacturing (AM process is the selective laser melting (SLM or direct metal laser sintering (DMLS process. SLM/DMLS can produce full-density metal parts from difficult materials, but it tends to suffer from severe residual stresses introduced during processing. This limits the usefulness and applicability of the process, particularly in the fabrication of parts with delicate overhanging and protruding features. The purpose of this study was to examine the current insight and progress made toward understanding and eliminating the problem in overhanging and protruding structures. To accomplish this, a survey of the literature was undertaken, focusing on process modeling (general, heat transfer, stress and distortion and material models, direct process control (input and environmental control, hardware-in-the-loop monitoring, parameter optimization and post-processing, experiment development (methods for evaluation, optical and mechanical process monitoring, imaging and design-of-experiments, support structure optimization and overhang feature design; approximately 143 published works were examined. The major findings of this study were that a small minority of the literature on SLM/DMLS deals explicitly with the overhanging stress problem, but some fundamental work has been done on the problem. Implications, needs and potential future research directions are discussed in-depth in light of the present review.
The engineer's anxiety about plant safety as viewed by the lawyer

International Nuclear Information System (INIS)

Lendi, M.

1981-01-01

The role of the design and operating engineers is described. The responsibilities of management is stressed and the legal and moral aspects of the problem are emphasized. The law can only give guidance but the ultimate responsibility rests with the design and operating staff. (G.R.S.)
An Introduction to Parallel Cluster Computing Using PVM for Computer Modeling and Simulation of Engineering Problems

International Nuclear Information System (INIS)

Spencer, VN

2001-01-01

An investigation has been conducted regarding the ability of clustered personal computers to improve the performance of executing software simulations for solving engineering problems. The power and utility of personal computers continues to grow exponentially through advances in computing capabilities such as newer microprocessors, advances in microchip technologies, electronic packaging, and cost effective gigabyte-size hard drive capacity. Many engineering problems require significant computing power. Therefore, the computation has to be done by high-performance computer systems that cost millions of dollars and need gigabytes of memory to complete the task. Alternately, it is feasible to provide adequate computing in the form of clustered personal computers. This method cuts the cost and size by linking (clustering) personal computers together across a network. Clusters also have the advantage that they can be used as stand-alone computers when they are not operating as a parallel computer. Parallel computing software to exploit clusters is available for computer operating systems like Unix, Windows NT, or Linux. This project concentrates on the use of Windows NT, and the Parallel Virtual Machine (PVM) system to solve an engineering dynamics problem in Fortran
A Study on Residual Stress Measurements by Using Laser Speckle Interferometry

International Nuclear Information System (INIS)

Rho, Kyung Wan; Kang, Young June; Hong, Seong Jin; Kang, Hyung Soo

1999-01-01

Residual stress is one of the causes which make defects in engineering components and materials. And interest in the measurement of residual stress exists in many industries. There are commonly used methods by which residual stresses are currently measured. But these methods have a little demerits: time consumption and other problems. Therefore we devised a new experimental technique to measure residual stress in materials with a combination of laser speckle pattern interferometry, finite element method and spot heating. The speckle pattern interferometer measures in-plane deformations while the heating provides for very localized stress relief. FEM is used for determining heat temperature and other parameters. The residual stresses are determined by the amount of strain that is measured subsequent to the heating and cool-down of the region being interrogated. A simple model is presented to provide a description of the method. In this paper, the ambiguity problem for the fringe patterns has solved by a phase shifting method
Food Selectivity, Mealtime Behavior Problems, Spousal Stress, and Family Food Choices in Children with and without Autism Spectrum Disorder

Science.gov (United States)

Curtin, C.; Hubbard, K.; Anderson, S. E.; Mick, E.; Must, A.; Bandini, L. G.

2015-01-01

Mealtime behavior problems and family stress occur frequently among families of children with autism spectrum disorder (ASD). However, it is unknown whether food selectivity is an associated factor. The associations of high food selectivity with mealtime behavior problems, spousal stress, and influence on family members were assessed among 53…
Modeling and simulation of different and representative engineering problems using Network Simulation Method

Science.gov (United States)

2018-01-01

Mathematical models simulating different and representative engineering problem, atomic dry friction, the moving front problems and elastic and solid mechanics are presented in the form of a set of non-linear, coupled or not coupled differential equations. For different parameters values that influence the solution, the problem is numerically solved by the network method, which provides all the variables of the problems. Although the model is extremely sensitive to the above parameters, no assumptions are considered as regards the linearization of the variables. The design of the models, which are run on standard electrical circuit simulation software, is explained in detail. The network model results are compared with common numerical methods or experimental data, published in the scientific literature, to show the reliability of the model. PMID:29518121
Occupational stress among nursing technicians and assistants: coping focused on the problem

Directory of Open Access Journals (Sweden)

Carla Araújo Bastos Teixeira

2015-04-01

Full Text Available Objective. To analyze the association between strategies used to cope with occupational stress that are focused on the problem wand the personal characteristics of nursing technicians and assistants. Methodology. This quantitative and correlational study was conducted in a large teaching hospital in the São Paulo State, Brazil, in 2013. A randomized sample with 310 participants (198 nursing assistants and 112 nursing technicians comprised the study population. Data were collected using a sociodemographic characteristics questionnaire and Scale of Ways of Coping with Problems. Data were submitted to univariate analysis, and variables with statistical significance (p<0.20 were submitted posteriorly in a multiple regression model. Results. Most employees were women (76.1% older than 40 years (67.7%, had nine to 11 years of formal education (73.5%, had a partner (58.7%, were Catholic (53.2%, and had children (74.5%. The final multiple regression model consisted of variable years of formal education and number of children. Conclusion. In this study, formal education and number of children were more strongly associated with a greater use of coping strategies focused on the problem. Such a strategy is related to minimal vulnerability to stress related to the working environment.
Stress Voiding in IC Interconnects - Rules of Evidence for Failure Analysts

Energy Technology Data Exchange (ETDEWEB)

FILTER, WILLIAM F.

1999-09-17

Mention the words ''stress voiding'', and everyone from technology engineer to manager to customer is likely to cringe. This IC failure mechanism elicits fear because it is insidious, capricious, and difficult to identify and arrest. There are reasons to believe that a damascene-copper future might be void-free. Nevertheless, engineers who continue to produce ICs with Al-alloy interconnects, or who assess the reliability of legacy ICs with long service life, need up-to-date insights and techniques to deal with stress voiding problems. Stress voiding need not be fearful. Not always predictable, neither is it inevitable. On the contrary, stress voids are caused by specific, avoidable processing errors. Analytical work, though often painful, can identify these errors when stress voiding occurs, and vigilance in monitoring the improved process can keep it from recurring. In this article, they show that a methodical, forensics approach to failure analysis can solve suspected cases of stress voiding. This approach uses new techniques, and patiently applies familiar ones, to develop evidence meeting strict standards of proof.
Promise and problems in using stress triggering models for time-dependent earthquake hazard assessment

Science.gov (United States)

Cocco, M.

2001-12-01

Earthquake stress changes can promote failures on favorably oriented faults and modify the seismicity pattern over broad regions around the causative faults. Because the induced stress perturbations modify the rate of production of earthquakes, they alter the probability of seismic events in a specified time window. Comparing the Coulomb stress changes with the seismicity rate changes and aftershock patterns can statistically test the role of stress transfer in earthquake occurrence. The interaction probability may represent a further tool to test the stress trigger or shadow model. The probability model, which incorporate stress transfer, has the main advantage to include the contributions of the induced stress perturbation (a static step in its present formulation), the loading rate and the fault constitutive properties. Because the mechanical conditions of the secondary faults at the time of application of the induced load are largely unkown, stress triggering can only be tested on fault populations and not on single earthquake pairs with a specified time delay. The interaction probability can represent the most suitable tool to test the interaction between large magnitude earthquakes. Despite these important implications and the stimulating perspectives, there exist problems in understanding earthquake interaction that should motivate future research but at the same time limit its immediate social applications. One major limitation is that we are unable to predict how and if the induced stress perturbations modify the ratio between small versus large magnitude earthquakes. In other words, we cannot distinguish between a change in this ratio in favor of small events or of large magnitude earthquakes, because the interaction probability is independent of magnitude. Another problem concerns the reconstruction of the stressing history. The interaction probability model is based on the response to a static step; however, we know that other processes contribute to

Ultrafine particles from diesel engines induce vascular oxidative stress via JNK activation.

Science.gov (United States)

Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

2009-03-15

Exposure to particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultrafine particles (UFP) from diesel vehicle engines have been shown to be proatherogenic in ApoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induce vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intracellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O(2)(-)) production in human aortic endothelial cells (HAEC). Flow cytometry showed that UFP increased MitoSOX red intensity specific for mitochondrial superoxide. Protein carbonyl content was increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated heme oxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pretreatment with the antioxidant N-acetylcysteine significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with the JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP-stimulated O(2)(-) production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation plays an important role in UFP-induced oxidative stress and stress response gene expression.
Thin film materials: stress, defect formation, and surface evolution

National Research Council Canada - National Science Library

Freund, L. B; Suresh, S

2003-01-01

... scientiﬁc basis with which stress, deformation and failure in thin ﬁlm materials can be characterized, an attempt is also made to link the scientiﬁc concepts to a broad range of practical applications through example problems, historical notes, case studies and exercises. Of particular interest to engineers, materials scientists and physicist...
Adapting Experiential Learning to Develop Problem-Solving Skills in Deaf and Hard-of-Hearing Engineering Students.

Science.gov (United States)

Marshall, Matthew M; Carrano, Andres L; Dannels, Wendy A

2016-10-01

Individuals who are deaf and hard-of-hearing (DHH) are underrepresented in science, technology, engineering, and mathematics (STEM) professions, and this may be due in part to their level of preparation in the development and retention of mathematical and problem-solving skills. An approach was developed that incorporates experiential learning and best practices of STEM instruction to give first-year DHH students enrolled in a postsecondary STEM program the opportunity to develop problem-solving skills in real-world scenarios. Using an industrial engineering laboratory that provides manufacturing and warehousing environments, students were immersed in real-world scenarios in which they worked on teams to address prescribed problems encountered during the activities. The highly structured, Plan-Do-Check-Act approach commonly used in industry was adapted for the DHH student participants to document and communicate the problem-solving steps. Students who experienced the intervention realized a 14.6% improvement in problem-solving proficiency compared with a control group, and this gain was retained at 6 and 12 months, post-intervention. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Engineering Risk Assessment of Space Thruster Challenge Problem

Science.gov (United States)

Mathias, Donovan L.; Mattenberger, Christopher J.; Go, Susie

2014-01-01

The Engineering Risk Assessment (ERA) team at NASA Ames Research Center utilizes dynamic models with linked physics-of-failure analyses to produce quantitative risk assessments of space exploration missions. This paper applies the ERA approach to the baseline and extended versions of the PSAM Space Thruster Challenge Problem, which investigates mission risk for a deep space ion propulsion system with time-varying thruster requirements and operations schedules. The dynamic mission is modeled using a combination of discrete and continuous-time reliability elements within the commercially available GoldSim software. Loss-of-mission (LOM) probability results are generated via Monte Carlo sampling performed by the integrated model. Model convergence studies are presented to illustrate the sensitivity of integrated LOM results to the number of Monte Carlo trials. A deterministic risk model was also built for the three baseline and extended missions using the Ames Reliability Tool (ART), and results are compared to the simulation results to evaluate the relative importance of mission dynamics. The ART model did a reasonable job of matching the simulation models for the baseline case, while a hybrid approach using offline dynamic models was required for the extended missions. This study highlighted that state-of-the-art techniques can adequately adapt to a range of dynamic problems.
Integrating Creativity Training into Problem and Project-Based Learning (PBL) Curriculum in Engineering Education

DEFF Research Database (Denmark)

Zhou, Chunfang

2012-01-01

In order to foster creative engineers, a creativity training programme was carried out in medialogy education in a Problem and Project-Based Learning (PBL) environment at Aalborg University, Denmark. This paper focuses on the question of how engineering students perceive the strategy of integrating...... creativity training into a PBL curriculum. A total of 20 medialogy students in the training programme were interviewed. The data shows that the training programme was thought useful and students get benefits such as gaining project work skills, creative concepts and confidence of being creative. However...
Massachusetts Institute of Technology School of Chemical Engineering Practice, Brookhaven station: Summary of projects, 1983-1986

International Nuclear Information System (INIS)

1987-11-01

The MIT Graduate School of Chemical Engineering Practice stresses engineering problem solving. The Practice School program, as it is commonly called, develops in a unique and particularly effective way the student's ability to apply fundamentals to problems in the chemical industry and thus accelerates one's professional development. The themes of atomization, emthanol production and utilization, hydrogen production and compression, localized electrochemical corrosion and biochemical engineering reflect some of the major programs at the Laboratory. The titles of all the projects are listed in chronological order in the index at the end of this document. Brief summaries are presented for each project with related projects grouped together
Stresses in a submarine topography under ocean waves

Energy Technology Data Exchange (ETDEWEB)

Mei, C.C.; McTigue, D.F.

1984-09-01

The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.
Governing Engineering

DEFF Research Database (Denmark)

Buch, Anders

2012-01-01

Most people agree that our world face daunting problems and, correctly or not, technological solutions are seen as an integral part of an overall solution. But what exactly are the problems and how does the engineering ‘mind set’ frame these problems? This chapter sets out to unravel dominant...... perspectives in challenge per-ception in engineering in the US and Denmark. Challenge perception and response strategies are closely linked through discursive practices. Challenge perceptions within the engineering community and the surrounding society are thus critical for the shaping of engineering education...... and the engineering profession. Through an analysis of influential reports and position papers on engineering and engineering education the chapter sets out to identify how engineering is problematized and eventually governed. Drawing on insights from governmentality studies the chapter strives to elicit the bodies...
Governing Engineering

DEFF Research Database (Denmark)

Buch, Anders

2011-01-01

Abstract: Most people agree that our world faces daunting problems and, correctly or not, technological solutions are seen as an integral part of an overall solution. But what exactly are the problems and how does the engineering ‘mind set’ frame these problems? This chapter sets out to unravel...... dominant perspectives in challenge perception in engineering in the US and Denmark. Challenge perception and response strategies are closely linked through discursive practices. Challenge perceptions within the engineering community and the surrounding society are thus critical for the shaping...... of engineering education and the engineering profession. Through an analysis of influential reports and position papers on engineering and engineering education the chapter sets out to identify how engineering is problematized and eventually governed. Drawing on insights from governmentality studies the chapter...
Genetically engineered Rice with transcription factor DREB genes for abiotic stress tolerance(abstract)

International Nuclear Information System (INIS)

Datta, S.K.; Datta, K.

2005-01-01

Water stress (drought and Salinity) is the most severe limitation to rice productivity. Several breeding approaches (MAS, QTL) applied to suitable genotypes are in place at IRRI and elsewhere. Phenotyping of water stress tolerance is in progress with potential predictability. Dr. Shinozaki's group has cloned a number of transcription factor genes, which have been shown to work in Arabidopsis to achieve drought, cold, and salinity tolerant plants. None of these genes have as yet displayed their potential functioning in rice. Genetic engineering aims at cross talk between different stress signaling pathways leading to stress tolerance. Osmotic Adjustment (OA) is an effective component of abiotic stress (drought and salinity) tolerance in many plants including rice. When plant experiences water stress, OA contributes to turgor maintenance of both shoots and roots. Conventional breeding could not achieve the OA in rice excepting a few rice cultivars, which are partially adapted to water-stress conditions. Several stress-related genes have now been cloned and transferred in to enhance the osmolytes and some transgenic lines showed increased tolerance to osmotic stress. A few strategies could be effectively deployed for a better understanding of water-stress tolerance in rice and to develop transgenic rice, which can survive for a critical period of water-stress conditions: 1) Switching on of transcription factor regulating the expression of several genes related to abiotic stress, 2) Use of a suitable stress inducible promoter driving the target gene for an efficient and directed expression in plants, 3) Understanding of phenotyping and GxE in a given environment, 4) Selection of a few adaptive rice cultivars suitable in drought/salinity prone areas, 5) Microarray, proteomics, QTL and MAS may expedite the cloning and characterizing the stress induced genes, and 6) Finally, the efficient transformation system for generating a large number of transgenic rice of different
Engineering-Based Problem Solving Strategies in AP Calculus: An Investigation into High School Student Performance on Related Rate Free-Response Problems

Science.gov (United States)

Thieken, John

2012-01-01

A sample of 127 high school Advanced Placement (AP) Calculus students from two schools was utilized to study the effects of an engineering design-based problem solving strategy on student performance with AP style Related Rate questions and changes in conceptions, beliefs, and influences. The research design followed a treatment-control multiple…
New Developments of Computational Fluid Dynamics and Their Applications to Practical Engineering Problems

Science.gov (United States)

Chen, Hudong

2001-06-01

There have been considerable advances in Lattice Boltzmann (LB) based methods in the last decade. By now, the fundamental concept of using the approach as an alternative tool for computational fluid dynamics (CFD) has been substantially appreciated and validated in mainstream scientific research and in industrial engineering communities. Lattice Boltzmann based methods possess several major advantages: a) less numerical dissipation due to the linear Lagrange type advection operator in the Boltzmann equation; b) local dynamic interactions suitable for highly parallel processing; c) physical handling of boundary conditions for complicated geometries and accurate control of fluxes; d) microscopically consistent modeling of thermodynamics and of interface properties in complex multiphase flows. It provides a great opportunity to apply the method to practical engineering problems encountered in a wide range of industries from automotive, aerospace to chemical, biomedical, petroleum, nuclear, and others. One of the key challenges is to extend the applicability of this alternative approach to regimes of highly turbulent flows commonly encountered in practical engineering situations involving high Reynolds numbers. Over the past ten years, significant efforts have been made on this front at Exa Corporation in developing a lattice Boltzmann based commercial CFD software, PowerFLOW. It has become a useful computational tool for the simulation of turbulent aerodynamics in practical engineering problems involving extremely complex geometries and flow situations, such as in new automotive vehicle designs world wide. In this talk, we present an overall LB based algorithm concept along with certain key extensions in order to accurately handle turbulent flows involving extremely complex geometries. To demonstrate the accuracy of turbulent flow simulations, we provide a set of validation results for some well known academic benchmarks. These include straight channels, backward
Tensile Instability and Artificial Stresses in Impact Problems in SPH

International Nuclear Information System (INIS)

Mehra, Vishal; Sijoy C D; Mishra, Vinayak; Chaturvedi, Shashank

2012-01-01

The smooth particle hydrodynamics (SPH) is a meshless computational technique that is popular in the modeling of impact and penetration problems. However, SPH is liable to a tensile instability that manifests itself as a bunching of nodes and formation of artificial voids and no generally accepted formulation exists to counter this instability. We examine the performance of two methods that have been proposed to deal with the tensile instability— the Monaghan artificial stresses and the Godunov-type SPH. The impact and penetration of 0.5 cm radii steel spheres on 2 mm thick aluminium plate at 3.1 km/s is chosen for comparison. We show that the artificial void formation in St-Al impact is suppressed but not eliminated by using Monaghan stresses while the void formation is entirely eliminated by using Godunov-type formulation of SPH that was proposed by Parshikov and Medin.
A hierarchical method for structural topology design problems with local stress and displacement constraints

DEFF Research Database (Denmark)

Stolpe, Mathias; Stidsen, Thomas K.

2005-01-01

In this paper we present a hierarchical optimization method for finding feasible true 0-1 solutions to finite element based topology design problems. The topology design problems are initially modeled as non-convex mixed 0-1 programs. The hierarchical optimization method is applied to the problem...... and then successively refined as needed. At each level of design mesh refinement, a neighborhood optimization method is used to solve the problem considered. The non-convex topology design problems are equivalently reformulated as convex all-quadratic mixed 0-1 programs. This reformulation enables the use of methods...... of minimizing the weight of a structure subject to displacement and local design-dependent stress constraints. The method iteratively solves a sequence of problems of increasing size of the same type as the original problem. The problems are defined on a design mesh which is initially coarse...
Organizational options for preventing work-related stress in knowledge work

DEFF Research Database (Denmark)

Ipsen, Christine; Jensen, Per Langaa

2012-01-01

Recent studies point to work-related stress as an increasing problem for knowledge workers. However, the working life in knowledge-intensive companies is often described as good and stimulating. The aim of this study is to explore the organizational options for preventing work-related problems...... in knowledge work. This calls for a study of the characteristics of knowledge work, stress management interventions and an in-depth analysis of the organizational factors causing frustrations and work-related problems in relation to knowledge work. In a qualitative study, 27 respondents were interviewed....... They represented different stakeholders in five Danish knowledge-intensive companies, which comprised two consultancies and three engineering consulting companies. The study shows that knowledge work comprises a paradox, since the same work-related or organizational issues could be experienced as both...
Spa therapy (balneotherapy) relieves mental stress, sleep disorder, and general health problems in sub-healthy people

Science.gov (United States)

Yang, Bei; Qin, Qi-zhong; Han, Ling-li; Lin, Jing; Chen, Yu

2018-02-01

To investigate the relieving effects of hot spring balneotherapy on mental stress, sleep disorder, general health problems, and women's health problems in sub-healthy people, we recruited 500 volunteers in sub-health in Chongqing, and 362 volunteers completed the project, including 223 in the intervention group and 139 in the control group. The intervention group underwent hot spring balneotherapy for 5 months, while the control group did not. The two groups took questionnaire investigation (general data, mental stress, emotional status, sleep quality, general health problems, as well as some women's health problems) and physical examination (height, weight, waist circumference, blood pressure, blood lipid, blood sugar) 5 months before and after the intervention, respectively. After intervention, sleep disorder (difficulty in falling asleep ( P = 0.017); dreaminess, nightmare suffering, and restless sleep ( P = 0.013); easy awakening ( P = 0.003) and difficulty in falling into sleep again after awakening( P = 0.016); and mental stress ( P = 0.031) and problems of general health (head pain ( P = 0.026), joint pain( P = 0.009), leg or foot cramps ( P = 0.001), blurred vision ( P = 0.009)) were relieved significantly in the intervention group, as compared with the control group. While other indicators (fatigue, eye tiredness, limb numbness, constipation, skin allergy) and women's health problems (breast distending pain; dysmenorrhea, irregular menstruation) were relieved significantly in the self-comparison of the intervention group before and after intervention ( P 0.05). All indications (except bad mood, low mood, and worry or irritability) in the intervention group significantly improved, with effect size from 0.096 to 1.302. Multiple logistic regression analysis showed that the frequency, length, and location of balneotherapy in the intervention group were the factors influencing emotion, sleep, and health condition ( P Physical examination found that waist
Anxiety, Depression, Problem Solving and Stress Management in Patients with Ankylosing Spondylitis

Directory of Open Access Journals (Sweden)

Yasemin Özkan

2018-04-01

Full Text Available Objective: This study aims to determine anxiety, depression, self-esteem, stress management and problem solving skills in ankylosing spondylitis (AS patients compared to healthy subjects. Materials and Methods: The study involves 33 patients with AS according to the Modified New York Criteria and 31 healthy subjects as control group. A socio-demographic data form, the Hospital Anxiety and Depression Scale (HADS, the Rosenberg Self-Esteem Scale (RSES, the Problem Solving Inventory (PSI and the Coping Orientation to Problems Experienced (COPE scale were used to evaluate participants. Results: The mean ages of the patients and the control were 36.3±10.9 and 33.6±6.2 years respectively with no significant difference between the two groups (p>0.05. On the HADS scale, AS patients showed significantly higher anxiety and depression scores (p<0.05. AS patients had significantly lower self-esteem as determined by the RSES scores (p<0.05. When the study groups were compared using the PSI, a significant difference was observed only in the “approach-avoidance style” subscale. A positive correlation between Bath Ankylosing Spondylitis Disease Activity Index (BASDAI and RSES was reported and there was a very strong negative correlation between BASDAI and overall PSI scores. A negative correlation was found between humor, mental disengagement and behavioral disengagement and BASDAI scores (p<0.05. Conclusion: Being a chronic rheumatic disease, AS not only limits daily living activities due to its physical manifestations but also causes psychological problems such as depression ve anxiety. However, it does not seem to impair problem solving skills and the ability to cope with stress significantly. It might be helpful to evaluate AS patients using a holistic approach and to be aware of the factors that are associated with difficulties in their social interactions.
Enhancing E. coli tolerance towards oxidative stress via engineering its global regulator cAMP receptor protein (CRP.

Directory of Open Access Journals (Sweden)

Souvik Basak

Full Text Available Oxidative damage to microbial hosts often occurs under stressful conditions during bioprocessing. Classical strain engineering approaches are usually both time-consuming and labor intensive. Here, we aim to improve E. coli performance under oxidative stress via engineering its global regulator cAMP receptor protein (CRP, which can directly or indirectly regulate redox-sensing regulators SoxR and OxyR, and other ~400 genes in E. coli. Error-prone PCR technique was employed to introduce modifications to CRP, and three mutants (OM1~OM3 were identified with improved tolerance via H(2O(2 enrichment selection. The best mutant OM3 could grow in 12 mM H(2O(2 with the growth rate of 0.6 h(-1, whereas the growth of wild type was completely inhibited at this H(2O(2 concentration. OM3 also elicited enhanced thermotolerance at 48°C as well as resistance against cumene hydroperoxide. The investigation about intracellular reactive oxygen species (ROS, which determines cell viability, indicated that the accumulation of ROS in OM3 was always lower than in WT with or without H(2O(2 treatment. Genome-wide DNA microarray analysis has shown not only CRP-regulated genes have demonstrated great transcriptional level changes (up to 8.9-fold, but also RpoS- and OxyR-regulated genes (up to 7.7-fold. qRT-PCR data and enzyme activity assay suggested that catalase (katE could be a major antioxidant enzyme in OM3 instead of alkyl hydroperoxide reductase or superoxide dismutase. To our knowledge, this is the first work on improving E. coli oxidative stress resistance by reframing its transcription machinery through its native global regulator. The positive outcome of this approach may suggest that engineering CRP can be successfully implemented as an efficient strain engineering alternative for E. coli.
Identity, Stress, and Behavioral and Emotional Problems in Undergraduates: Evidence for Interaction Effects

Science.gov (United States)

Burt, Keith B.; Paysnick, Amy A.

2014-01-01

The present study examined sense of identity (assessed using the Identity subscale of the Psychosocial Maturity Inventory) as a moderator of associations between stressful life events, behavioral/emotional problems, and substance abuse in a sample of 187 college undergraduates (67% female). Correlations showed evidence for positive associations…
Daily Stress Magnifies the Association between Cognitive Decline and Everyday Memory Problems: An Integration of Longitudinal and Diary Methods

Science.gov (United States)

Rickenbach, Elizabeth H.; Almeida, David M.; Seeman, Teresa E.; Lachman, Margie E.

2014-01-01

We examined whether long-term fluid cognitive decline was associated with memory problems in everyday life, and whether stress plays a moderating role. We expected that the association between cognitive decline and everyday memory problems would be magnified in the context of self-reported and physiological stress. Data are from the Boston Longitudinal Study, a subsample of the Midlife in the United States study. Participants in the current study (n=112) completed a battery of tests measuring fluid cognitive functioning at Time 1 (T1) and 2 (T2) over ten years. At T2, participants completed weekly diaries of self-reported daily stressors and everyday memory problems for twelve consecutive weeks. Also at T2, participants provided four saliva samples over the course of one day to assess physiological stress using diurnal cortisol profiles [cortisol awakening response (CAR) and diurnal cortisol slope (DCS)]. Self-reported daily stressors and a less healthy DCS were associated with more everyday memory problems, and participants with greater cognitive decline reported more memory problems compared to those with less or no decline. Self-reported daily stressors and CAR moderated the relationship of cognitive decline and memory problems. As expected, more cognitive decline was associated with greater increases in memory problems on weeks when individuals reported more daily stressors and for individuals with a less healthy CAR. The current findings can inform interventions aimed to identify factors, such as daily stress, that contribute to daily functioning in the context of cognitive decline. PMID:25365691

14 CFR 33.62 - Stress analysis.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Stress analysis. 33.62 Section 33.62... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.62 Stress analysis. A stress analysis must be performed on each turbine engine showing the design safety margin of each turbine...
STRESSED STATE OF ROCKY SUBSOIL IN THE VICINITY OF A CIRCULAR SECTION HYDRAULIC ENGINEERING TUNNEL TAKING INTO ACCOUNT THE ANISOTROPY OF THE GROUND MEDIUM

Directory of Open Access Journals (Sweden)

D. T. Bautdinov

2016-01-01

Full Text Available Objectives. The aim of this study consists ina parametric analysis of the stress state of transversely isotropic rocky ground in the vicinity of a circular cross-sectional hydraulic tunnel taking into account the dead load of the subsoil medium under various relations of the elastic characteristics of the subsoil environment in orthogonal directions and at different angles of inclination of the plane of isotropy. Methods. A transversely isotropic medium model (a special case of an anisotropic medium is applied, in which the subsoil in one plane has the characteristics of an isotropic medium (isotropic plane but in a perpendicular direction – in contradistinction to the characteristics of an isotropic medium.The angle of isotropic planar inclination models the oblique bedding of subsoil layers. Results. The determination of tangential stresses on the contour generation allows the strength of the subsoil medium to be estimated at different depths of emplacement. The calculation of extensive hydraulic engineering tunnels, constructed in strong, transversely isotropic rocky ground, is reduced to a problem of plane strain elasticity theory for a transversely isotropic medium surrounding the tunnel construction. Since the solution of this problem cannot be achieved using analytical methods, the analysis of the stress state was carried out by finite element method using the ANSYS software complex. The type and size of the finite element appropriate for the calculation were pre-identified based on solutions to the task of verification. For the verificatory task, the Kirsch problem was adopted. Conclusion.When designing underground structures, it is necessary to determine the physical and mechanical properties of rocky soils in greater detail and to pay special attention to the elastic characteristics. The absence of tensile stresses in the upper section of development with some relations of the moduli of deformation and Poisson's ratios benefit the
Genetic engineering: a promising tool to engender physiological, biochemical and molecular stress resilience in green microalgae

Directory of Open Access Journals (Sweden)

Freddy eGuiheneuf

2016-03-01

Full Text Available As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest towards a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy to fix atmospheric CO2 into algal biomass, mitigating fossil CO2 pollution in the process. Remarkably, a feature innate to most microalgae is synthesis and accumulation of lipids (60–65% of dry weight, carbohydrates and secondary metabolites like pigments and vitamins, especially when grown under abiotic stress conditions. Particularly fruitful, such an application of abiotic stress factors like nitrogen starvation , salinity, heat shock etc. can be used in a biorefinery concept for production of multiple valuable products. The focus of this mini-review underlies metabolic reorientation practices and tolerance mechanisms as applied to green microalgae under specific stress stimuli for a sustainable pollution-free future. Moreover, we entail current progress on genetic engineering as a promising tool to grasp adaptive processes for improving strains with potential biotechnological interests.
The Effect on Pupils' Science Performance and Problem-Solving Ability through Lego: An Engineering Design-Based Modeling Approach

Science.gov (United States)

Li, Yanyan; Huang, Zhinan; Jiang, Menglu; Chang, Ting-Wen

2016-01-01

Incorporating scientific fundamentals via engineering through a design-based methodology has proven to be highly effective for STEM education. Engineering design can be instantiated for learning as they involve mental and physical stimulation and develop practical skills especially in solving problems. Lego bricks, as a set of toys based on design…
Solving bi-level optimization problems in engineering design using kriging models

Science.gov (United States)

Xia, Yi; Liu, Xiaojie; Du, Gang

2018-05-01

Stackelberg game-theoretic approaches are applied extensively in engineering design to handle distributed collaboration decisions. Bi-level genetic algorithms (BLGAs) and response surfaces have been used to solve the corresponding bi-level programming models. However, the computational costs for BLGAs often increase rapidly with the complexity of lower-level programs, and optimal solution functions sometimes cannot be approximated by response surfaces. This article proposes a new method, namely the optimal solution function approximation by kriging model (OSFAKM), in which kriging models are used to approximate the optimal solution functions. A detailed example demonstrates that OSFAKM can obtain better solutions than BLGAs and response surface-based methods, and at the same time reduce the workload of computation remarkably. Five benchmark problems and a case study of the optimal design of a thin-walled pressure vessel are also presented to illustrate the feasibility and potential of the proposed method for bi-level optimization in engineering design.
Temperament Moderates Associations between Exposure to Stress and Children's Externalizing Problems

Science.gov (United States)

Schermerhorn, Alice C.; Bates, John E.; Goodnight, Jackson A.; Lansford, Jennifer E.; Dodge, Kenneth A.; Pettit, Gregory S.

2013-01-01

The interaction between a temperament profile (four groups determined by high vs. low resistance to control [unmanageability] and unadaptability [novelty distress]) and family stress in predicting externalizing problems at school in children followed from kindergarten through eighth grade (ages 5-13) was investigated. The sample consisted of 556…
Stresses in a submarine topography under ocean waves

Energy Technology Data Exchange (ETDEWEB)

Mei, C.C.; McTigue, D.F.

1984-01-01

The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.
THE TRAVELLING SALESMAN PROBLEM IN THE ENGINEERING EDUCATION PROGRAMMING CURRICULUM

Directory of Open Access Journals (Sweden)

Yevgeny Gayev

2017-11-01

Full Text Available Objective: To make students familiar with the famous Traveling Salesman Problem (TSP and suggest the latter to become a common exercise in engineering programming curriculum provided the students master computer science in the easy programming environment MATLAB. Methods: easy programming in MATLAB makes true such modern educational approach as “discovery based” methodology. Results: a MATLAB TSP-program oriented to Ukrainian map is suggested that allows to pictorially demonstrate the process of optimal route search with an option to decelerate or accelerate the demonstration. The program is guessed to be useful both for learning the TSP as one of fundamental logistics problems and as an intriguing programming curriculum excersize. Several sub-programs according to key stone Computer Science Curriculum have also been suggested. This lies in line with recent “discovery based” learning methodology. Discussion: we explain how to create this program for visual discrete optimization, suggest required subprograms belonging to key stone programming algorithms including rather modern graphical user interface (GUI, how to use this MATLAB TSP-program for demonstration the drastical grows of solution time required. Conclusions: easy programming being realized in MATLAB makes dificult curriculum problems attractive to students; it focuses them to main problem’ features, laws and algorithms implementing the “discovery based” methodology in such a way.
Exploring violence exposure, stress, protective factors and behavioral problems among inner-city youth.

Science.gov (United States)

Youngstrom, Eric; Weist, Mark D; Albus, Kathleen E

2003-09-01

This study examined relationships between violence exposure, other stressors, family support, and self-concept on self-reported behavioral problems among 320 urban adolescents (aged 11-18) referred for mental health treatment. Overall, participants reported high levels of violence exposure, with a median of six past encounters with violence as a witness, victim, or through the experiences of associates. All forms of violence exposure (witnessing, being a victim, knowing of victims) were correlated with internalizing and externalizing behavioral problems for males and females. Total violence exposure predicted behavioral problems among participants, even after controlling for the effects of other risk, demographic and protective factors. Family support and self-concept moderated the influence of life stress and cumulative risk on problem behavior outcomes, but these protective variables did not significantly moderate violence exposure.
Nondestructive Induced Residual Stress Assessment in Superalloy Turbine Engine Components Using Induced Positron Annihilation (IPA)

International Nuclear Information System (INIS)

Rideout, C. A.; Ritchie, S. J.; Denison, A.

2007-01-01

Induced Positron Analysis (IPA) has demonstrated the ability to nondestructively quantify shot peening/surface treatments and relaxation effects in single crystal superalloys, steels, titanium and aluminum with a single measurement as part of a National Science Foundation SBIR program and in projects with commercial companies. IPA measurement of surface treatment effects provides a demonstrated ability to quantitatively measure initial treatment effectiveness along with the effect of operationally induced changes over the life of the treated component. Use of IPA to nondestructively quantify surface and subsurface residual stresses in turbine engine materials and components will lead to improvements in current engineering designs and maintenance procedures
Wildland fire management. Volume 1: Prevention methods and analysis. [systems engineering approach to California fire problems

Science.gov (United States)

Weissenberger, S. (Editor)

1973-01-01

A systems engineering approach is reported for the problem of reducing the number and severity of California's wildlife fires. Prevention methodologies are reviewed and cost benefit models are developed for making preignition decisions.
Impacts of Autistic Behaviors, Emotional and Behavioral Problems on Parenting Stress in Caregivers of Children with Autism

Science.gov (United States)

Huang, Chien-Yu; Yen, Hsui-Chen; Tseng, Mei-Hui; Tung, Li-Chen; Chen, Ying-Dar; Chen, Kuan-Lin

2014-01-01

This study examined the effects of autistic behaviors and individual emotional and behavioral problems on parenting stress in caregivers of children with autism. Caregivers were interviewed with the Childhood Autism Rating Scale and completed the Strength and Difficulties Questionnaire and the Parenting Stress Index Short Form. Results revealed…
Mapping of Mechanical Strains and Stresses around Quiescent Engineered Three-Dimensional Epithelial Tissues

Science.gov (United States)

Gjorevski, Nikolce; Nelson, Celeste M.

2012-01-01

Understanding how physical signals guide biological processes requires qualitative and quantitative knowledge of the mechanical forces generated and sensed by cells in a physiologically realistic three-dimensional (3D) context. Here, we used computational modeling and engineered epithelial tissues of precise geometry to define the experimental parameters that are required to measure directly the mechanical stress profile of 3D tissues embedded within native type I collagen. We found that to calculate the stresses accurately in these settings, we had to account for mechanical heterogeneities within the matrix, which we visualized and quantified using confocal reflectance and atomic force microscopy. Using this technique, we were able to obtain traction forces at the epithelium-matrix interface, and to resolve and quantify patterns of mechanical stress throughout the surrounding matrix. We discovered that whereas single cells generate tension by contracting and pulling on the matrix, the contraction of multicellular tissues can also push against the matrix, causing emergent compression. Furthermore, tissue geometry defines the spatial distribution of mechanical stress across the epithelium, which communicates mechanically over distances spanning hundreds of micrometers. Spatially resolved mechanical maps can provide insight into the types and magnitudes of physical parameters that are sensed and interpreted by multicellular tissues during normal and pathological processes. PMID:22828342
Effects of stress and alcohol cues in men with and without problem gambling and alcohol use disorder.

Science.gov (United States)

Steinberg, Lindsay; Tremblay, Anne-Marie; Zack, Martin; Busto, Usoa E; Zawertailo, Laurie A

2011-12-01

Relapse is a serious challenge in problem gambling (PG), as it is in substance addiction. Stress and cues are implicated in relapse in both conditions. However, experimental research on motivational effects of stress in PG subjects is scant. This study examined subjective-motivational, cognitive and physiological effects of stress and alcohol cues in subjects with PG, alcohol use disorder (AD), co-occurring PG and AD (CO), and healthy controls (HC). Fifty-two (12/clinical group; 16 HC) physically healthy men received stress in the form of 10-min uncontrollable noise (U-Noise vs. controllable noise; C-Noise) and cues (355 ml non-alcoholic 'placebo' beer; P-Beer vs. soft drink) under Separate or Combined conditions on two test sessions. Visual analogue scales assessed subjective effects. Emotional Stroop and Go/No-Go 'Shift' tasks assessed inhibitory control. Systolic blood pressure (SBP) indexed physiological reactivity. U-Noise and C-Noise increased desire for alcohol in all groups. U-Noise selectively inhibited desire to gamble in PG subjects. Both U-Noise and C-Noise inhibited desire to gamble in CO subjects. Neither manipulation reliably altered cognitive performance. Compared to Neutral words, Alcohol words impaired Stroop color-naming in all groups except PG, which displayed relatively faster color-naming of Alcohol words (facilitation). U-Noise increased SBP relative to C-Noise in AD and HC groups. U-Noise plus P-Beer and U-Noise per se decreased SBP in PG and CO groups, respectively. Noise stress has opposite motivational and physiological effects in men with problem gambling vs. alcohol use disorder. A homeostatic process may explain the impact of stress in problem gamblers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Finite element methods for engineering sciences. Theoretical approach and problem solving techniques

Energy Technology Data Exchange (ETDEWEB)

Chaskalovic, J. [Ariel University Center of Samaria (Israel); Pierre and Marie Curie (Paris VI) Univ., 75 (France). Inst. Jean le Rond d' Alembert

2008-07-01

This self-tutorial offers a concise yet thorough grounding in the mathematics necessary for successfully applying FEMs to practical problems in science and engineering. The unique approach first summarizes and outlines the finite-element mathematics in general and then, in the second and major part, formulates problem examples that clearly demonstrate the techniques of functional analysis via numerous and diverse exercises. The solutions of the problems are given directly afterwards. Using this approach, the author motivates and encourages the reader to actively acquire the knowledge of finite- element methods instead of passively absorbing the material, as in most standard textbooks. The enlarged English-language edition, based on the original French, also contains a chapter on the approximation steps derived from the description of nature with differential equations and then applied to the specific model to be used. Furthermore, an introduction to tensor calculus using distribution theory offers further insight for readers with different mathematical backgrounds. (orig.)
A Return to Innovative Engineering Design, Critical Thinking and Systems Engineering

Science.gov (United States)

Camarda, Charles J.

2007-01-01

I believe we are facing a critical time where innovative engineering design is of paramount importance to the success of our aerospace industry. However, the very qualities and attributes necessary for enhancing, educating, and mentoring a creative spirit are in decline in important areas. The importance of creativity and innovation in this country was emphasized by a special edition of the Harvard Business Review OnPoint entitled: "The Creative Company" which compiled a series of past and present articles on the subject of creativity and innovation and stressed its importance to our national economy. There is also a recognition of a lack of engineering, critical thinking and problem-solving skills in our education systems and a trend toward trying to enhance those skills by developing K-12 educational programs such as Project Lead the Way, "Science for All Americans", Benchmarks 2061 , etc. In addition, with respect to spacecraft development, we have a growing need for young to mid-level engineers with appropriate experience and skills in spacecraft design, development, analysis, testing, and systems engineering. As the Director of Engineering at NASA's Johnson Space Center, I realized that sustaining engineering support of an operational human spacecraft such as the Space Shuttle is decidedly different than engineering design and development skills necessary for designing a new spacecraft such as the Crew Exploration Vehicle of the Constellation Program. We learned a very important lesson post Columbia in that the Space Shuttle is truly an experimental and not an operational vehicle and the strict adherence to developed rules and processes and chains of command of an inherently bureaucratic organizational structure will not protect us from a host of known unknowns let alone unknown unknowns. There are no strict rules, processes, or procedures for understanding anomalous results of an experiment, anomalies with an experimental spacecraft like Shuttle, or in the
Mindfulness-Based Stress Reduction for Parents of Young Children with Developmental Delays: Implications for Parental Mental Health and Child Behavior Problems

Science.gov (United States)

Neece, Cameron L.

2014-01-01

Background: Parents of children with developmental delays (DD) typically report elevated levels of parental stress compared with parents of typically developing children. Children with DD are also at high risk for exhibiting significant behaviour problems. Parental stress has been shown to impact the development of these behaviour problems;…
The Primary Experiments of an Analysis of Pareto Solutions for Conceptual Design Optimization Problem of Hybrid Rocket Engine

Science.gov (United States)

Kudo, Fumiya; Yoshikawa, Tomohiro; Furuhashi, Takeshi

Recentry, Multi-objective Genetic Algorithm, which is the application of Genetic Algorithm to Multi-objective Optimization Problems is focused on in the engineering design field. In this field, the analysis of design variables in the acquired Pareto solutions, which gives the designers useful knowledge in the applied problem, is important as well as the acquisition of advanced solutions. This paper proposes a new visualization method using Isomap which visualizes the geometric distances of solutions in the design variable space considering their distances in the objective space. The proposed method enables a user to analyze the design variables of the acquired solutions considering their relationship in the objective space. This paper applies the proposed method to the conceptual design optimization problem of hybrid rocket engine and studies the effectiveness of the proposed method.
Engineering Ethics Education : Its Necessity, Objectives, Methods, Current State, and Challenges

Science.gov (United States)

Fudano, Jun

The importance of engineering ethics education has become widely recognized in the industrialized countries including Japan. This paper examines the background against which engineering ethics education is required, and reviews its objectives, methods, and challenges, as well as its current state. In pointing out important issues associated with the apparent acceptance and quantitative development of ethics education, especially after the establishment of the Japan Accreditation Board for Engineering Education in 1999, the author stresses that the most serious problem is the lack of common understanding on the objectives of engineering ethics education. As a strategy to improve the situation, the so-called “Ethics-across-the-Curriculum” approach is introduced. The author also claims that business/organization ethics which is consistent with engineering ethics should be promoted in Japan.
A Systems Engineering Approach to Address Human Capital Management Issues in the Shipbuilding Industry

Science.gov (United States)

2008-09-01

sons Nicholas and David. They each experienced the highs and lows (and stress ) of the SEM PD-21 Program as much or more than I, and took up the...Langford, 2007b). For example, a 57 telecommuter (stakeholder) may have a problem with the speed of their home internet service. Needs derived...industry have echoed this need. In Keane’s (2007) presentation to the National Naval Engineering Education Conference, he stressed that successful

[Assessment of parental stress using the "Eltern-Belastungs-Screening zur Kindeswohlgefährdung" (EBSK) - association with emotional and behavioral problems in children].

Science.gov (United States)

Eichler, Anna K; Glaubitz, Katharina A; Hartmann, Luisa C; Spangler, Gottfried

2014-07-01

Parental stress is increased in clinical contexts (e.g., child psychiatry) and correlates with behavioral and emotional problems of children. In addition, parental stress can result in a biased parental perception of child's behavior and emotions. These interrelations were examined in a normal (N = 320) and a clinical (N = 75) sample. The "Eltern-Belastungs-Screening zur Kindeswohlgefährdung" (EBSK; Deegener, Spangler, Körner & Becker, 2009) was used for the assessment of parental stress. As expected, increased EBSK scores were overrepresented in the clinical sample. In both samples stressed parents reported having children with more behavioral and emotional problems. Children of stressed parents in turn reported significantly less problems than their parents did. The rating of independent third persons, e.g. teachers, was not available and should be added in future research. Restrictions in methodology and conclusions for practice are discussed.
Divergence identities in curved space-time. A resolution of the stress-energy problem

International Nuclear Information System (INIS)

Yilmaz, H.; Tufts Univ., Medford, MA

1989-01-01

It is noted that the joint use of two basic differential identities in curved space-time, namely. 1) the Einstein-Hilbert identity (1915), and 2) the identity of P. Freud (1939), permits a viable alternative to general relativity and a resolution of the field stress-energy' problem of the gravitational theory. (orig.)
A nationwide study of health-related quality of life, stress, pain or discomfort and the use of medicine among problem gamblers

DEFF Research Database (Denmark)

Ekholm, Ola; Davidsen, Michael; Larsen, Christina Viskum Lytken

2018-01-01

AIM: The aim of this study was to investigate the associations between problem gambling and health-related quality of life, stress, pain or discomfort and the use of analgesics and sleeping pills. METHODS: Data derives from the Danish Health and Morbidity Survey 2010. The survey was based......, high perception of stress, headache, fatigue and sleeping problems. Furthermore, previous problem gambling was generally associated with poorer health outcomes. Thus, current and previous problem gamblers had 2.36 times (95% confidence interval [CI] 1.44-3.87) and 1.66 times (95% CI 1.07-2.55) higher...... included topics such as health-related quality of life (Short Form-12), perceived stress, pain and discomforts within the past two weeks, as well as the use of medication within the past two weeks. RESULTS: Current problem gambling was strongly associated with negative outcomes such as poor mental health...
Do post-trauma symptoms mediate the relation between neurobiological stress parameters and conduct problems in girls?

Science.gov (United States)

Babel, Kimberly A; Jambroes, Tijs; Oostermeijer, Sanne; van de Ven, Peter M; Popma, Arne; Vermeiren, Robert R J M; Doreleijers, Theo A H; Jansen, Lucres M C

2016-01-01

Attenuated activity of stress-regulating systems has consistently been reported in boys with conduct problems. Results in studies of girls are inconsistent, which may result from the high prevalence of comorbid post-trauma symptoms. Therefore, the aim of the present study is to investigate post-trauma symptoms as a potential mediator in the relation between stress-regulation systems functioning and conduct problems in female adolescents. The sample consisted of 78 female adolescents (mean age 15.4; SD 1.1) admitted to a closed treatment institution. The diagnosis of disruptive behaviour disorder (DBD) was assessed by a structured interview-the diagnostic interview schedule for children version IV (DISC-IV). To assess post-trauma symptoms and externalizing behaviour problems, self-report questionnaires, youth self report (YSR) and the trauma symptom checklist for Children (TSCC) were used. The cortisol awakenings response (CAR) measured hypothalamic-pituitary-adrenal (HPA) axis activity, whereas autonomous nervous system (ANS) activity was assessed by heart rate (HR), pre-ejection period (PEP) and respiratory sinus arrhythmia (RSA). Independent t-tests were used to compare girls with and without DBD, while path analyses tested for the mediating role of post- trauma symptoms in the relation between stress regulating systems and externalizing behaviour. Females with DBD (n = 37) reported significantly higher rates of post-trauma symptoms and externalizing behaviour problems than girls without DBD (n = 39). Path analysis found no relation between CAR and externalizing behaviour problems. With regard to ANS activity, positive direct effects on externalizing behaviour problems were present for HR (standardized β = 0.306, p = 0.020) and PEP (standardized β = -0.323, p = 0.031), though not for RSA. Furthermore, no relation-whether direct or indirect-could be determined from post-trauma symptoms. Present findings demonstrate that the neurobiological
Engineered Nanomaterials Elicit Cellular Stress Responses

Science.gov (United States)

Engineered nanomaterials are being developed continuously and incorporated into consumer products, resulting in increased human exposures. The study of engineered nanomaterials has focused largely on toxicity endpoints without further investigating potential mechanisms or pathway...
Engineering Complex Tissues

Science.gov (United States)

MIKOS, ANTONIOS G.; HERRING, SUSAN W.; OCHAREON, PANNEE; ELISSEEFF, JENNIFER; LU, HELEN H.; KANDEL, RITA; SCHOEN, FREDERICK J.; TONER, MEHMET; MOONEY, DAVID; ATALA, ANTHONY; VAN DYKE, MARK E.; KAPLAN, DAVID; VUNJAK-NOVAKOVIC, GORDANA

2010-01-01

This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and vasculogenesis, explained that the vascular arrangement precedes and dictates the architecture of the new bone, and proposed that engineering of osseous tissues might benefit from preconstruction of an appropriate vasculature. Jennifer Elisseeff explored the formation of complex tissue structures based on the example of stratified cartilage engineered using stem cells and hydrogels. Helen Lu discussed engineering of tissue interfaces, a problem critical for biological fixation of tendons and ligaments, and the development of a new generation of fixation devices. Rita Kandel discussed the challenges related to the re-creation of the cartilage-bone interface, in the context of tissue engineered joint repair. Frederick Schoen emphasized, in the context of heart valve engineering, the need for including the requirements derived from “adult biology” of tissue remodeling and establishing reliable early predictors of success or failure of tissue engineered implants. Mehmet Toner presented a review of biopreservation techniques and stressed that a new breakthrough in this field may be necessary to meet all the needs of tissue engineering. David Mooney described systems providing temporal and spatial regulation of growth factor availability, which may find utility in virtually all tissue engineering and regeneration applications, including directed in vitro and in vivo vascularization of tissues. Anthony Atala offered a clinician’s perspective for functional tissue
A hierarchical method for discrete structural topology design problems with local stress and displacement constraints

DEFF Research Database (Denmark)

Stolpe, Mathias; Stidsen, Thomas K.

2007-01-01

In this paper, we present a hierarchical optimization method for finding feasible true 0-1 solutions to finite-element-based topology design problems. The topology design problems are initially modelled as non-convex mixed 0-1 programs. The hierarchical optimization method is applied to the problem...... and then successively refined as needed. At each level of design mesh refinement, a neighbourhood optimization method is used to treat the problem considered. The non-convex topology design problems are equivalently reformulated as convex all-quadratic mixed 0-1 programs. This reformulation enables the use of methods...... of minimizing the weight of a structure subject to displacement and local design-dependent stress constraints. The method iteratively treats a sequence of problems of increasing size of the same type as the original problem. The problems are defined on a design mesh which is initially coarse...
Automation of reverse engineering process in aircraft modeling and related optimization problems

Science.gov (United States)

Li, W.; Swetits, J.

1994-01-01

During the year of 1994, the engineering problems in aircraft modeling were studied. The initial concern was to obtain a surface model with desirable geometric characteristics. Much of the effort during the first half of the year was to find an efficient way of solving a computationally difficult optimization model. Since the smoothing technique in the proposal 'Surface Modeling and Optimization Studies of Aerodynamic Configurations' requires solutions of a sequence of large-scale quadratic programming problems, it is important to design algorithms that can solve each quadratic program in a few interactions. This research led to three papers by Dr. W. Li, which were submitted to SIAM Journal on Optimization and Mathematical Programming. Two of these papers have been accepted for publication. Even though significant progress has been made during this phase of research and computation times was reduced from 30 min. to 2 min. for a sample problem, it was not good enough for on-line processing of digitized data points. After discussion with Dr. Robert E. Smith Jr., it was decided not to enforce shape constraints in order in order to simplify the model. As a consequence, P. Dierckx's nonparametric spline fitting approach was adopted, where one has only one control parameter for the fitting process - the error tolerance. At the same time the surface modeling software developed by Imageware was tested. Research indicated a substantially improved fitting of digitalized data points can be achieved if a proper parameterization of the spline surface is chosen. A winning strategy is to incorporate Dierckx's surface fitting with a natural parameterization for aircraft parts. The report consists of 4 chapters. Chapter 1 provides an overview of reverse engineering related to aircraft modeling and some preliminary findings of the effort in the second half of the year. Chapters 2-4 are the research results by Dr. W. Li on penalty functions and conjugate gradient methods for
Chemical engineering problems of radioactive waste fixation by vitrification

International Nuclear Information System (INIS)

Taylor, R.F.

1985-01-01

Basic features are reviewed of the chemical engineering problems faced in the vitrification of the high-level radioactive liquid wastes resulting from the reprocessing of nuclear fuel. After an outline of glass solution properties and formation kinetics the constituent elements of the vitrification route are examined in turn: waste feed evaporation and denitration, calcination, offgas treatment, and finally melting and product quality. Plant and experimental data for each stage are discussed with comparison between process routes and with reference to the underlying principles. Attention is drawn to the future need for higher trapping efficiencies and for dealing with a wider range of species in offgas treatments as higher burnup fuels are processed after shorter cooling times from reactor. Two areas of present study where deeper insight into underlying process mechanics is needed are, firstly, the association of waste material with glass formers in the wet or sinter stages and secondly their incorporation and mixing reaction in the melt. Fuller understanding here would bring direct benefit to process performance and handling. The problems discussed are not of a nature to jeopardize the vitrification routes but if product quality does come to rely heavily on process control then demonstrable confidence in the behaviour of the central physico-chemical interactions is indispensable. (author)
Analysis of Stress Updates in the Material-point Method

DEFF Research Database (Denmark)

Andersen, Søren; Andersen, Lars

2009-01-01

The material-point method (MPM) is a new numerical method for analysis of large strain engineering problems. The MPM applies a dual formulation, where the state of the problem (mass, stress, strain, velocity etc.) is tracked using a finite set of material points while the governing equations...... are solved on a background computational grid. Several references state, that one of the main advantages of the material-point method is the easy application of complicated material behaviour as the constitutive response is updated individually for each material point. However, as discussed here, the MPM way...
Preschoolers’ Genetic, Physiological, and Behavioral Sensitivity Factors Moderate Links Between Parenting Stress and Child Internalizing, Externalizing, and Sleep Problems

Science.gov (United States)

Davis, Molly; Thomassin, Kristel; Bilms, Joanie; Suveg, Cynthia; Shaffer, Anne; Beach, Steven R. H.

2017-01-01

This study examined three potential moderators of the relations between maternal parenting stress and preschoolers’ adjustment problems: a genetic polymorphism - the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator - children’s baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator - mothers’ reports of children’s negative emotionality. A total of 108 mothers (Mage = 30.68 years, SDage = 6.06) reported on their parenting stress as well as their preschoolers’ (Mage = 3.50 years, SDage = .51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed. PMID:28295263
Parenting Stress and Child Behavior Problems within Families of Children with Developmental Disabilities: Transactional Relations across 15 Years

Science.gov (United States)

Woodman, Ashley C.; Mawdsley, Helena P.; Hauser-Cram, Penny

2015-01-01

Parents of children with developmental disabilities (DD) are at increased risk of experiencing psychological stress compared to other parents. Children's high levels of internalizing and externalizing problems have been found to contribute to this elevated level of stress. Few studies have considered the reverse direction of effects, however, in…
Maternal Health Status and Parenting Stress in Low-Income, Ethnic-Minority Mothers of Children with Conduct Disorder Problems: the Role of Daily Parenting Hassles.

Science.gov (United States)

BeLue, Rhonda; Halgunseth, Linda C; Abiero, Beatrice; Bediako, Phylicia

2015-12-01

Minimal attention has been given to understanding parenting stress among low-income, ethnically diverse mothers of children with conduct problems. Maternal health and parenting hassles may serve as important risk factors for parenting stress. This study examined whether parenting hassles mediated the relations between maternal physical and mental health and parenting stress in a sample of low-income, ethnically diverse mothers of children with behavioral problems. The sample included 177 low-income black, Latina, and white mothers of kindergartners with behavior problems. Path analysis was employed to assess the associations between maternal mental and physical health and parenting stress, as well as the moderating role of parenting hassles in this cross-sectional study. After adjusting for covariates, we found that parenting hassles mediated the relationship between social support and parenting stress as well as maternal health and parenting stress. Findings suggest that promoting coping resources for daily parenting hassles and supporting the physical and mental health of minority mothers may have important implications for parenting children with high behavior problems.
Finite Element Analysis of a Four-Cylinder Four Stroke Gasoline Engine Crankshaft

Directory of Open Access Journals (Sweden)

Parman Setyamartana

2014-07-01

Full Text Available Stress analysis of a crankshaft using traditional method is complicated and needs modification by considering its stress concentration factors. To solve this problem, the crankshaft strength of a four-cylinder four stroke gasoline engine is modeled and analyzed using finite element method (FEM in this paper. For this purpose, the crankshaft is modeled using CATIA software in detail. Then, the model is imported in ANSYS. In the recent software, the model is meshed into a number of finite elements. After defining the boundary and loading conditions, the stresses occur in the crankshaft are analyzed in order to identify critical locations on it.
Project-organized learning and the development of competences in Engineering Education for Sustainable Development

DEFF Research Database (Denmark)

Guerra, Aida; Holgaard, Jette Egelund; Kolmos, Anette

2013-01-01

by the complex and economically driven society and develop innovative technologies to solve and prevent sustainable problems. In this perspective, ESD experts have stressed sustainability aspects as well as cross-disciplinary competences, such as inter-disciplinarity, adaptability, problem solving, critical...... thinking, systems thinking, etc. It is argued that Problem-Based Learning (PBL) provides a suitable framework for developing the competences mentioned, but there is a lack of studies that investigate the room which PBL practice leaves for ESD. In this study, we aim to investigate the staff’s perception......The integration of Education for Sustainable Development (ESD) principles has been claimed for all levels and areas of formal education. The integration of new kinds of competences, skills and knowledge into the engineering curricula aims to prepare future engineers to face the challenges posed...
Predictors of prescribed medication use for depression, anxiety, stress, and sleep problems in mid-aged Australian women.

Science.gov (United States)

Schofield, Margot J; Khan, Asaduzzaman

2014-11-01

The study examined prevalence of self-reported use of medication recommended or prescribed by a doctor for depression, anxiety, stress, and sleep problems; and modelled baseline factors that predicted use over 3 years for each condition. Analyses were undertaken on the 2001 and 2004 surveys of mid-aged women in the Australian Longitudinal Study on Women's Health. Dependent variables were self-reported use in past 4 weeks of medications recommended or prescribed by a doctor for depression, anxiety, stress, or sleep problems in 2001 and 2004. Generalized Estimating Equations (GEE) were used to predict medication use for each condition over 3 years. Prevalence of prescribed medication use (2001, 2004) for each condition was depression (7.2, 8.9 %), anxiety (7.4, 9.0 %), stress (4.8, 5.7 %), and sleep problems (8.7, 9.5 %). Multivariable analyses revealed that odds of medication use across 3 years in all four conditions were higher for women with poorer mental and physical health, using hormone replacement therapy (HRT), or having seen a counsellor; and increased over time for depression, anxiety, and stress models. Medication use for depression was also higher for overweight/obese women, ex-smokers, and unmarried. Medication use for anxiety was higher for unmarried and non-working/low occupational women. Medication use for stress was higher for non-working women. Additional predictors of medication for sleep were surgical menopause, and area of residence. Self-reported use of prescribed medication for four mental health conditions is increased over time after controlling for mental and physical health and other variables. Research needs to explore decision-making processes influencing differential rates of psychoactive medication use and their relationship with health outcomes.
Engineering mechanics

CERN Document Server

Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal

Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...
Perceived Child Behavior Problems, Parenting Stress, and Maternal Depressive Symptoms among Prenatal Methamphetamine Users

Science.gov (United States)

Liles, Brandi D.; Newman, Elana; LaGasse, Linda L.; Derauf, Chris; Shah, Rizwan; Smith, Lynne M.; Arria, Amelia M.; Huestis, Marilyn A.; Haning, William; Strauss, Arthur; DellaGrotta, Sheri; Dansereau, Lynne M.; Neal, Charles; Lester, Barry M.

2012-01-01

The present study was designed to examine parenting stress, maternal depressive symptoms, and perceived child behavior problems among mothers who used methamphetamine (MA) during pregnancy. Participants were a subsample (n = 212; 75 exposed, 137 comparison) of biological mothers who had continuous custody of their child from birth to 36 months.…
COMPI Fertility Problem Stress Scales is a brief, valid and reliable tool for assessing stress in patients seeking treatment

DEFF Research Database (Denmark)

Sobral, Maria P.; Costa, Maria E.; Schmidt, Lone

2017-01-01

comparability of fertility-related stress across genders and countries. STUDY DESIGN SIZE, DURATION Cross-sectional study. First, we tested the structure of the COMPI-FPSS. Then, reliability and validity (convergent and discriminant) were examined for the final model. Finally, measurement invariance both across...... genders and cultures was tested. PARTICIPANTS/MATERIALS, SETTING, METHODS Our final sample had 3923 fertility patients (1691 men and 2232 women) recruited in clinical settings from seven different countries: Denmark, China, Croatia, Germany, Greece, Hungary and Sweden. Participants had a mean age of 34......STUDY QUESTION Are the Copenhagen Multi‐Centre Psychosocial Infertility research program Fertility Problem Stress Scales (COMPI-FPSS) a reliable and valid measure across gender and culture? SUMMARY ANSWER The COMPI-FPSS is a valid and reliable measure, presenting excellent or good fit...
Neural responses to threat and reward interact to predict stress-related problem drinking: A novel protective role of the amygdala

Science.gov (United States)

2012-01-01

Background Research into neural mechanisms of drug abuse risk has focused on the role of dysfunction in neural circuits for reward. In contrast, few studies have examined the role of dysfunction in neural circuits of threat in mediating drug abuse risk. Although typically regarded as a risk factor for mood and anxiety disorders, threat-related amygdala reactivity may serve as a protective factor against substance use disorders, particularly in individuals with exaggerated responsiveness to reward. Findings We used well-established neuroimaging paradigms to probe threat-related amygdala and reward-related ventral striatum reactivity in a sample of 200 young adult students from the ongoing Duke Neurogenetics Study. Recent life stress and problem drinking were assessed using self-report. We found a significant three-way interaction between threat-related amygdala reactivity, reward-related ventral striatum reactivity, and recent stress, wherein individuals with higher reward-related ventral striatum reactivity exhibit higher levels of problem drinking in the context of stress, but only if they also have lower threat-related amygdala reactivity. This three-way interaction predicted both contemporaneous problem drinking and problem drinking reported three-months later in a subset of participants. Conclusions These findings suggest complex interactions between stress and neural responsiveness to both threat and reward mediate problem drinking. Furthermore, they highlight a novel protective role for threat-related amygdala reactivity against drug use in individuals with high neural reactivity to reward. PMID:23151390

Intelligent Engine Systems Work Element 1.2: Malfunction and Operator Error Reduction

Science.gov (United States)

Wiseman, Matthew

2005-01-01

Jet engines, although highly reliable and safe, do experience malfunctions that cause flight delays, passenger stress, and in some cases, in conjunction with inappropriate crew response, contribute to airplane accidents. On rare occasions, the anomalous engine behavior is not recognized until it is too late for the pilots to do anything to prevent or mitigate the resulting engine malfunction causing in-flight shutdowns (IFSDs), aborted takeoffs (ATOs), or loss of thrust control (LOTC). In some cases, the crew response to a myriad of external stimuli and existing training procedures is the source of the problem mentioned above. The problem is the reduction of jet engine malfunctions (IFSDs, ATOs, and LOTC) and inappropriate crew response (PSM+ICR) through the use of evolving and advanced technologies. The solution is to develop the overall system health maintenance architecture, detection and accommodation technologies, processes, and enhanced crew interfaces that would enable a significant reduction in IFSDs, ATOs, and LOTC. This program defines requirements and proposes a preliminary design concept of an architecture that enables the realization of the solution.
The mediation roles of discrepancy stress and self-esteem between masculine role discrepancy and mental health problems.

Science.gov (United States)

Yang, Xue; Lau, Joseph T F; Wang, Zixin; Ma, Yee-Ling; Lau, Mason C M

2018-08-01

Masculine role discrepancy and discrepancy stress occur when men perceive that they fail to live up to the ideal manhood derived from societal prescriptions. The present study examined the associations between masculine role discrepancy and two emotional and mental health problems (social anxiety and depressive symptoms), and potential mediation effects through discrepancy stress and self-esteem in a male general population. Based on random population-based sampling, 2000 male residents in Hong Kong were interviewed. Levels of masculine role discrepancy, discrepancy stress, self-esteem, social anxiety, and depressive symptoms were assessed by using validated scales. Results of structural equation modeling analysis indicated that the proposed model fit the sample well. (χ 2 (118) = 832.34, p masculine role discrepancy, discrepancy stress, and emotional/mental health problems. We found that discrepancy stress significantly mediated the association between masculine role discrepancy and social anxiety, while self-esteem significantly mediated the associations between masculine role discrepancy and both social anxiety and depression. Study limitations mainly included the cross-sectional design and reliance on self-reported questionnaires. The associations between masculine discrepancy and social anxiety/depressive symptoms among men may be explained by the increase in discrepancy stress and decrease in self-esteem. The findings suggest needs and directions for future research for the relationship between masculine role discrepancy and men's mental health, mechanisms involved, and interventions for improvement. Copyright © 2018. Published by Elsevier B.V.
The Analysis of Stress Waves at a Junction of Beam and String

Directory of Open Access Journals (Sweden)

Mu Chen

2018-01-01

Full Text Available In the bridge engineering, there are some problems about the dynamics that traditional theory cannot solve. So, the theory about stress waves is introduced to solve the related problems. This is a new attempt that the mechanic theory is applied to practical engineering. The stress wave at a junction of the structure composed of beams and strings is investigated in this paper. The structure is studied because the existence of a soft rope makes the transmission of the force in the bridge structure different from the traditional theory, and it is the basis for further research. The equilibrium equations of the displacement and the internal force are built based on the hypothesis. The fast Fourier transform (FFT numerical algorithm is used to express an incident pulse of arbitrary shape. The analytical solutions are substantiated by comparing with the finite element programs. The conclusion that if the cross section of the string is relatively small, then the energy density of the structure is relatively large, which is disadvantageous to the structure, can be obtained from this paper.
Learning Styles of Science and Engineering Students in Problem and Project Based Education

DEFF Research Database (Denmark)

Kolmos, Anette; Holgaard, Jette Egelund

2008-01-01

At the Faculty of Engineering and Science at Aalborg University, Denmark, process skills are an integrated part of the curriculum objectives. During the first year programme, a special course in Collaboration, Learning and Project Management (CLP) is given to develop those skills. In order...... to develop students’ learning and the CLP-course, the Felder-Soloman Index of Learning Styles (ILS®) has been used in that course and data has been collected to investigate whether some learning style preferences are more conspicuous that others in a problem based learning environment. The results show, more...... pronounced than similar studies, that the first year engineering students at Aalborg University are considerable more active than reflective. This results leads to a discussion of whether reflection and conceptualization should be facilitated further in the curriculum to balance the students learning style...
Student Engagement in a Structured Problem-Based Approach to Learning: A First-Year Electronic Engineering Study Module on Heat Transfer

Science.gov (United States)

Montero, E.; Gonzalez, M. J.

2009-01-01

Problem-based learning has been at the core of significant developments in engineering education in recent years. This term refers to any learning environment in which the problem drives the learning, because it is posed in such a way that students realize they need to acquire new knowledge before the problem can be solved. This paper presents the…
A Comparison of Students' Perceptions of Stress in Parallel Problem-Based and Lecture-Based Curricula.

Science.gov (United States)

Wardley, C Sonia; Applegate, E Brooks; Almaleki, A Deyab; Van Rhee, James A

2016-03-01

A 6-year longitudinal study was conducted to compare the perceived stress experienced during a 2-year master's physician assistant program by 5 cohorts of students enrolled in either problem-based learning (PBL) or lecture-based learning (LBL) curricular tracks. The association of perceived stress with academic achievement was also assessed. Students rated their stress levels on visual analog scales in relation to family obligations, financial concerns, schoolwork, and relocation and overall on 6 occasions throughout the program. A mixed model analysis of variance examined the students' perceived level of stress by curriculum and over time. Regression analysis further examined school work-related stress after controlling for other stressors and possible lag effect of stress from the previous time point. Students reported that overall stress increased throughout the didactic year followed by a decline in the clinical year with statistically significant curricular (PBL versus LBL) and time differences. PBL students also reported significantly more stress resulting from school work than LBL students at some time points. Moreover, when the other measured stressors and possible lag effects were controlled, significant differences between PBL and LBL students' perceived stress related to school work persisted at the 8- and 12-month measurement points. Increased stress in both curricula was associated with higher achievement in overall and individual organ system examination scores. Physician assistant programs that embrace a PBL pedagogy to prepare students to think clinically may need to provide students with additional support through the didactic curriculum.
Multi-objective optimization problems concepts and self-adaptive parameters with mathematical and engineering applications

CERN Document Server

Lobato, Fran Sérgio

2017-01-01

This book is aimed at undergraduate and graduate students in applied mathematics or computer science, as a tool for solving real-world design problems. The present work covers fundamentals in multi-objective optimization and applications in mathematical and engineering system design using a new optimization strategy, namely the Self-Adaptive Multi-objective Optimization Differential Evolution (SA-MODE) algorithm. This strategy is proposed in order to reduce the number of evaluations of the objective function through dynamic update of canonical Differential Evolution parameters (population size, crossover probability and perturbation rate). The methodology is applied to solve mathematical functions considering test cases from the literature and various engineering systems design, such as cantilevered beam design, biochemical reactor, crystallization process, machine tool spindle design, rotary dryer design, among others.
Development of a problem - based learning (PBL) and cooperative learning (CL) transportation engineering course For undergraduate students.

Science.gov (United States)

2008-08-01

This study reports the findings of a project that was done during the implementation of a : problem-based learning (PBL) and cooperative learning (CL) elements into an : undergraduate transportation engineering course. The study procedure used the st...
The mediating effects of self-esteem and coronary-prone behavior on problem solving and affect under low and high stress.

Science.gov (United States)

Hubbs-Tait, L; Blodgett, C J

1989-01-01

Self-esteem and coronary-prone behavior were identified as two personality constructs related to different stress responses. It was hypothesized that in the case of low self-esteem Type A subjects the conflicting stress responses would have a particularly adverse effect on problem-solving behavior, mood, and self-perception. Subjects were 32 Type A and 32 Type B males evenly divided into high and low self-esteem groups. Half of the subjects in each group solved 10 matrix problems under high stress, half under low stress. Compared with high self-esteem Type As, low self-esteem Type As under high stress became more hostile and perceived themselves as more tense and more hurried. They also tended to make more errors. Results are interpreted as implying that low and high self-esteem Type A subjects are not psychologically homogeneous. It is suggested that the two groups may differ substantially in terms of cardiovascular risk.
A review of creep analysis and design under multi-axial stress states

International Nuclear Information System (INIS)

Yao, H.-T.; Xuan Fuzhen; Wang Zhengdong; Tu Shantung

2007-01-01

The existence of multi-axial states of stress cannot be avoided in elevated temperature components. It is essential to understand the associated failure mechanisms and to predict the lifetime in practice. Although metal creep has been studied for about 100 years, many problems are still unsolved, in particular for those involving multi-axial stresses. In this work, a state-of-the-art review of creep analysis and engineering design is carried out, with particular emphasis on the effect of multi-axial stresses. The existing theories and creep design approaches are grouped into three categories, i.e., the classical plastic theory (CPT) based approach, the cavity growth mechanism (CGM) based approach and the continuum damage mechanics (CDM) based approach. Following above arrangements, the constitutive equations and design criteria are addressed. In the end, challenges on the precise description of the multi-axial creep behavior and then improving the strength criteria in engineering design are presented
Engineering graphics theoretical foundations of engineering geometry for design

CERN Document Server

Brailov, Aleksandr Yurievich

2016-01-01

This professional treatise on engineering graphics emphasizes engineering geometry as the theoretical foundation for communication of design ideas with real world structures and products. It considers each theoretical notion of engineering geometry as a complex solution of direct- and inverse-problems of descriptive geometry and each solution of basic engineering problems presented is accompanied by construction of biunique two- and three-dimension models of geometrical images. The book explains the universal structure of formal algorithms of the solutions of positional, metric, and axonometric problems, as well as the solutions of problems of construction in developing a curvilinear surface. The book further characterizes and explains the added laws of projective connections to facilitate construction of geometrical images in any of eight octants. Laws of projective connections allow constructing the complex drawing of a geometrical image in the American system of measurement and the European system of measu...
Middle School Engineering Problem Solving Using Traditional vs. e-PBL Module Instruction

Science.gov (United States)

Baele, Loren C.

This multiple methods (Denzin, 1978) study investigated two instructional approaches, traditional module and electronic Problem-Based Learning instruction (e-PBL), used within a middle school engineering classroom focused on the variables of engagement, content knowledge, student self-assessment and teacher assessment of problem solving solutions. A non-equivalent group quasi-experimental research design (Creswell, 2015) was used on middle school students (N = 100) between those that received traditional module instruction (n = 51) and e-PBL instruction (n = 49). The qualitative approach of triangulation (Jick, 1979) was used to identify emergent themes for both between and within methods of data analysis on student engagement survey responses, two days of field observations notes, and six student interview transcripts. The quantitative results identified that students who received e-PBL instruction self-reported significantly greater engagement than those who received traditional module instruction. Further, there was a significant interaction effect between engineering content knowledge by group and gender as males who received e-PBL instruction had greater growth of content knowledge scores than males receiving traditional instruction, while females who received traditional instruction had greater growth of content knowledge scores than females in the e-PBL group. Through triangulation of the qualitative data, the emergent themes of the study suggest that hands-on learning produces higher levels of reported engagement independent of instructional method. The emergence of problem solving fatigue developed when both study groups reported a decline in engagement when entering into the final phase of the quantitative study suggesting that too many complex, ill-structured problems in rapid succession may negatively impact student engagement. Although females within the treatment group were most engaged, they did not achieve the knowledge growth of the females in the
Probing Earth's State of Stress

Science.gov (United States)

Delorey, A. A.; Maceira, M.; Johnson, P. A.; Coblentz, D. D.

2016-12-01

The state of stress in the Earth's crust is a fundamental physical property that controls both engineered and natural systems. Engineered environments including those for hydrocarbon, geothermal energy, and mineral extraction, as well those for storage of wastewater, carbon dioxide, and nuclear fuel are as important as ever to our economy and environment. Yet, it is at spatial scales relevant to these activities where stress is least understood. Additionally, in engineered environments the rate of change in the stress field can be much higher than that of natural systems. In order to use subsurface resources more safely and effectively, we need to understand stress at the relevant temporal and spatial scales. We will present our latest results characterizing the state of stress in the Earth at scales relevant to engineered environments. Two important components of the state of stress are the orientation and magnitude of the stress tensor, and a measure of how close faults are to failure. The stress tensor at any point in a reservoir or repository has contributions from both far-field tectonic stress and local density heterogeneity. We jointly invert seismic (body and surface waves) and gravity data for a self-consistent model of elastic moduli and density and use the model to calculate the contribution of local heterogeneity to the total stress field. We then combine local and plate-scale contributions, using local indicators for calibration and ground-truth. In addition, we will present results from an analysis of the quantity and pattern of microseismicity as an indicator of critically stressed faults. Faults are triggered by transient stresses only when critically stressed (near failure). We show that tidal stresses can trigger earthquakes in both tectonic and reservoir environments and can reveal both stress and poroelastic conditions.
Parenting Stress Related to Behavioral Problems and Disease Severity in Children with Problematic Severe Asthma

NARCIS (Netherlands)

Verkleij, Marieke; van de Griendt, Erik-Jonas; Colland, Vivian; van Loey, Nancy; Beelen, Anita; Geenen, Rinie

2015-01-01

Our study examined parenting stress and its association with behavioral problems and disease severity in children with problematic severe asthma. Research participants were 93 children (mean age 13.4 +/- A 2.7 years) and their parents (86 mothers, 59 fathers). As compared to reference groups
Fibrocartilage tissue engineering: the role of the stress environment on cell morphology and matrix expression.

Science.gov (United States)

Thomopoulos, Stavros; Das, Rosalina; Birman, Victor; Smith, Lester; Ku, Katherine; Elson, Elliott L; Pryse, Kenneth M; Marquez, Juan Pablo; Genin, Guy M

2011-04-01

Although much is known about the effects of uniaxial mechanical loading on fibrocartilage development, the stress fields to which fibrocartilaginous regions are subjected to during development are mutiaxial. That fibrocartilage develops at tendon-to-bone attachments and in compressive regions of tendons is well established. However, the three-dimensional (3D) nature of the stresses needed for the development of fibrocartilage is not known. Here, we developed and applied an in vitro system to determine whether fibrocartilage can develop under a state of periodic hydrostatic tension in which only a single principal component of stress is compressive. This question is vital to efforts to mechanically guide morphogenesis and matrix expression in engineered tissue replacements. Mesenchymal stromal cells in a 3D culture were exposed to compressive and tensile stresses as a result of an external tensile hydrostatic stress field. The stress field was characterized through mechanical modeling. Tensile cyclic stresses promoted spindle-shaped cells, upregulation of scleraxis and type one collagen, and cell alignment with the direction of tension. Cells experiencing a single compressive stress component exhibited rounded cell morphology and random cell orientation. No difference in mRNA expression of the genes Sox9 and aggrecan was observed when comparing tensile and compressive regions unless the medium was supplemented with the chondrogenic factor transforming growth factor beta3. In that case, Sox9 was upregulated under static loading conditions and aggrecan was upregulated under cyclic loading conditions. In conclusion, the fibrous component of fibrocartilage could be generated using only mechanical cues, but generation of the cartilaginous component of fibrocartilage required biologic factors in addition to mechanical cues. These studies support the hypothesis that the 3D stress environment influences cell activity and gene expression in fibrocartilage development.
Preschoolers' genetic, physiological, and behavioral sensitivity factors moderate links between parenting stress and child internalizing, externalizing, and sleep problems.

Science.gov (United States)

Davis, Molly; Thomassin, Kristel; Bilms, Joanie; Suveg, Cynthia; Shaffer, Anne; Beach, Steven R H

2017-05-01

This study examined three potential moderators of the relations between maternal parenting stress and preschoolers' adjustment problems: a genetic polymorphism-the short allele of the serotonin transporter (5-HTTLPR, ss/sl allele) gene, a physiological indicator-children's baseline respiratory sinus arrhythmia (RSA), and a behavioral indicator-mothers' reports of children's negative emotionality. A total of 108 mothers (M age = 30.68 years, SD age = 6.06) reported on their parenting stress as well as their preschoolers' (M age = 3.50 years, SD age = 0.51, 61% boys) negative emotionality and internalizing, externalizing, and sleep problems. Results indicated that the genetic sensitivity variable functioned according to a differential susceptibility model; however, the results involving physiological and behavioral sensitivity factors were most consistent with a diathesis-stress framework. Implications for prevention and intervention efforts to counter the effects of parenting stress are discussed. © 2017 Wiley Periodicals, Inc.
Class and Home Problems: Optimization Problems

Science.gov (United States)

Anderson, Brian J.; Hissam, Robin S.; Shaeiwitz, Joseph A.; Turton, Richard

2011-01-01

Optimization problems suitable for all levels of chemical engineering students are available. These problems do not require advanced mathematical techniques, since they can be solved using typical software used by students and practitioners. The method used to solve these problems forces students to understand the trends for the different terms…
Racial discrimination, post traumatic stress, and gambling problems among urban Aboriginal adults in Canada.

Science.gov (United States)

Currie, Cheryl L; Wild, T Cameron; Schopflocher, Donald P; Laing, Lory; Veugelers, Paul; Parlee, Brenda

2013-09-01

Little is known about risk factors for problem gambling (PG) within the rapidly growing urban Aboriginal population in North America. Racial discrimination may be an important risk factor for PG given documented associations between racism and other forms of addictive behaviour. This study examined associations between racial discrimination and problem gambling among urban Aboriginal adults, and the extent to which this link was mediated by post traumatic stress. Data were collected via in-person surveys with a community-based sample of Aboriginal adults living in a mid-sized city in western Canada (N = 381) in 2010. Results indicate more than 80 % of respondents experienced discrimination due to Aboriginal race in the past year, with the majority reporting high levels of racism in that time period. Past year racial discrimination was a risk factor for 12-month problem gambling, gambling to escape, and post traumatic stress disorder (PTSD) symptoms in bootstrapped regression models adjusted for confounders and other forms of social trauma. Elevated PTSD symptoms among those experiencing high levels of racism partially explained the association between racism and the use of gambling to escape in statistical models. These findings are the first to suggest racial discrimination may be an important social determinant of problem gambling for Aboriginal peoples. Gambling may be a coping response that some Aboriginal adults use to escape the negative emotions associated with racist experiences. Results support the development of policies to reduce racism directed at Aboriginal peoples in urban areas, and enhanced services to help Aboriginal peoples cope with racist events.
Parenting Stress Related to Behavioral Problems and Disease Severity in Children with Problematic Severe Asthma

NARCIS (Netherlands)

Verkleij, Marieke; van de Griendt, E-J.; Colland, V.; Van Loey, N.E.E.; Beelen, A.; Geenen, R.

2015-01-01

Our study examined parenting stress and its association with behavioral problems and disease severity in children with problematic severe asthma. Research participants were 93 children (mean age 13.4 ± 2.7 years) and their parents (86 mothers, 59 fathers). As compared to reference groups analyzed in
Maternal mind-mindedness and toddler behavior problems: The moderating role of maternal trauma and posttraumatic stress.

Science.gov (United States)

Easterbrooks, M Ann; Crossman, Molly K; Caruso, Alessandra; Raskin, Maryna; Miranda-Julian, Claudia

2017-10-01

Maternal mind-mindedness (MM) reflects a caregiver's tendency to view a child as an individual with an independent mind. Research has linked higher MM with more favorable parenting and child adaptation. The aim of this study was to examine whether MM was associated with toddlers' behavior problems and competence, and the moderating role of trauma and posttraumatic stress disorder (PTSD) in a sample (N = 212) of adolescent mothers and their toddlers. MM was coded from maternal utterances during free play; mothers completed the University of California at Los Angeles Trauma and Posttraumatic Stress Disorder Reaction Index and reported on children's behavior problems and competence using the Brief Infant-Toddler Social and Emotional Assessment. The majority of mothers (84%) experienced trauma; 45% of these mothers met criteria for partial or full PTSD. Trauma was related to greater behavior problems, and PTSD moderated MM-child functioning relations. When mothers experienced full PTSD, there was no relation between MM and behavior problems. With child competence, when compared to children of mothers with no trauma exposure, children of mothers experiencing partial PTSD symptoms were more likely to have delays in competence when mothers made more MM comments. Results are discussed in light of how MM, in the context of trauma and PTSD, may affect parenting.

The Relationship between Parenting Stress and Behavior Problems of Children with Autistic Spectrum Disorders

Science.gov (United States)

Osborne, Lisa A.; Reed, Phil

2009-01-01

Two 9- to 10-month-Iong studies (N = 137) examined the interaction between parenting stress and behavior problems in children with autistic spectrum disorders (ASDs). Study 1 focused on very young children, and Study 2 employed a wider range of child ages; both studies assessed these factors at 2 points in time. The researchers noted a strong…
Relative deprivation in the Nordic countries-child mental health problems in relation to parental financial stress.

Science.gov (United States)

Gunnarsdóttir, Hrafnhildur; Hensing, Gunnel; Povlsen, Lene; Petzold, Max

2016-04-01

The Nordic welfare system has been acknowledged as favourable for children, successfully contributing to low child mortality and poverty rates. Nevertheless, mental health problems among children and adolescents are common and the economic situation of the family has been highlighted as an important determinant. In spite of similar social, political and cultural structures, the Nordic countries differ; Iceland was most affected by the global financial crisis in 2008. The aim of this study was to examine potential differences in parental financial stress and the associations to child mental health between the Nordic countries as well as age and gender differences. The study sample consisted of 6330 children aged 4-16 years old included in the 2011 version of the Nordic Study of Children's Health, Wellbeing and Quality of life. The Strengths and Difficulties Questionnaire was used to measure mental health problems. In Iceland, 47.7% of the parents reported financial stress while ≤20% did so in the other countries except for Finland (33.5%). However, in case of parental financial stress the OR of mental health problems comparing children to parents with and without financial stress was significantly lower among the Icelandic children (OR 1.60, 95% CI 1.15-2.24) than among the others: Denmark OR 3.07 (95% CI 2.15-4.39), Finland OR 2.28 (95% CI 1.60-3.25), Norway OR 2.77 (95% CI 1.86-4.12), Sweden OR 3.31(95% CI 2.26-4.86). No significant age or gender differences in the ORs were observed. Besides socioeconomic situation, relative deprivation should be considered an important determinant of child mental health. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
Solving some problems of engineering seismology by structural method

International Nuclear Information System (INIS)

Ishtev, K.G.; Hadjikov, L.M.; Dineva, P.S.; Jordanov, P.P.

1983-01-01

The work suggests a method for solving the direct and inverse problems of the engineer seismology by means of the structural approach of the systems theory. This approach gives a possibility for a simultaneous accounting of the two basic types of damping of the seismic signals in the earth foundation-geometrical damping and a damping in consequence of a dissipative energy loss. By the structural scheme an automatic account is made of the geometric damping of the signals. The damping from a dissipative energy loss on the other hand is accounted for through a choice of the type of frequency characteristics or the transmission functions of the different layers. With a few examples the advantages of the model including the two types of attenuation of the seismic signal are illustrated. An integral coefficient of damping is calculated which analogously to the frequency functions represents a generalized characteristic of is the whole earth foundation. (orig./HP)
Fuel Saving Strategy in Spark Ignition Engine Using Fuzzy Logic Engine Torque Control

OpenAIRE

Aris Triwiyatno; Sumardi

2012-01-01

In the case of injection gasoline engine, or better known as spark ignition engines, an effort to improve engine performance as well as to reduce fuel consumption is a fairly complex problem. Generally, engine performance improvement efforts will lead to increase in fuel consumption. However, this problem can be solved by implementing engine torque control based on intelligent regulation such as the fuzzy logic inference system. In this study, fuzzy logic engine torque regulation is used to c...
Bioarcheology has a "health" problem: conceptualizing "stress" and "health" in bioarcheological research.

Science.gov (United States)

Temple, Daniel H; Goodman, Alan H

2014-10-01

This article provides a critical historical overview of the stress concept in bioarcheological research and critically evaluates the term "health" in reference to skeletal samples. Stress has a considerable history in 20th century physiological research, and the term has reached a critical capacity of meaning. Stress was operationalized around a series of generalized physiological responses that were associated with a deviation from homeostasis. The term was incorporated into anthropological research during the mid-20th century, and further defined in bioarcheological context around a series of skeletal indicators of physiological disruption and disease. Emphases on stress became a predominate area of research in bioarcheology, and eventually, many studies utilized the terms "health" and "stress" interchangeably as part of a broader, problem-oriented approach to evaluating prehistoric population dynamics. Use of the term "health" in relation to skeletal samples is associated with the intellectual history of bioarcheological research, specifically influences from cultural ecology and processualist archeology and remains problematic for two reasons. First, health represents a comprehensive state of well-being that includes physiological status and individual perception, factors that cannot be readily observed in skeletal samples. Second, the categorization of populations into relative levels of health represents a typological approach, however unintentional. This article advocates for the integration of methodological and theoretical advances from human biology and primatology, while simultaneously incorporating the theoretical constructs associated with social epidemiology into bioarcheological research. Such an approach will significantly increase the applicability of bioarcheological findings to anthropological and evolutionary research, and help realize the goal of a truly relevant bioarcheological paradigm. Copyright © 2014 Wiley Periodicals, Inc.
Problem-Based and Project-Based Learning in Engineering and Medicine: Determinants of Students' Engagement and Persistence

Science.gov (United States)

Bédard, Denis; Lison, Christelle; Dalle, Daniel; Côté, Daniel; Boutin, Noël

2012-01-01

This paper presents results of a study conducted with undergraduate students involved in either problem- or project-based curricula (Medicine and Engineering, respectively) at the Université de Sherbrooke, Canada. The objective of the present research was to measure the impact of these innovative curricula on students' engagement and persistence…
Adapting Experiential Learning to Develop Problem-Solving Skills in Deaf and Hard-of-Hearing Engineering Students

Science.gov (United States)

Marshall, Matthew M.; Carrano, Andres L.; Dannels, Wendy A.

2016-01-01

Individuals who are deaf and hard-of-hearing (DHH) are underrepresented in science, technology, engineering, and mathematics (STEM) professions, and this may be due in part to their level of preparation in the development and retention of mathematical and problem-solving skills. An approach was developed that incorporates experiential learning and…
Fluvial gravel stabilization by net-spinning Hydropsychid caddisflies: exploring the magnitude and geographic scope of ecosystem engineering effect and evaluating resistance to anthropogenic stresses

Science.gov (United States)

Daniels, M.; Albertson, L.; Sklar, L. S.; Tumolo, B.; Mclaughlin, M. K.

2017-12-01

Several studies have demonstrated the substantial effects that organisms can have on earth surface processes. Known as ecosystem engineers, in streams these organisms maintain, modify, or create physical habitat structure by influencing fluvial processes such as gravel movement, fine sediment deposition and bank erosion. However, the ecology of ecosystem engineers and the magnitude of ecosystem engineering effects in a world increasingly influence by anthropogenically-driven changes is not well understood. Here we present a synthesis of research findings on the potential gravel stabilization effects of Hydropsychid caddisflies, a globally distributed group of net-spinning insects that live in the benthic substrate of most freshwater streams. Hydropsychid caddisflies act as ecosystem engineers because these silk structures can fundamentally alter sediment transport conditions, including sediment stability and flow currents. The silk nets spun by these insects attach gravel grains to one another, increasing the shear stress required to initiate grain entrainment. In a series of independent laboratory experiments, we investigate the gravel size fractions most affected by these silk attachments. We also investigate the role of anthropogenic environmental stresses on ecosystem engineering potential by assessing the impact of two common stressors, high fine sediment loads and stream drying, on silk structures. Finally, an extensive field survey of grain size and Hydropsychid caddisfly population densities informs a watershed-scale network model of Hydropsychid caddisfly gravel stabilizing potential. Our findings provide some of the first evidence that caddisfly silk may be a biological structure that is resilient to various forms of human-mediated stress and that the effects of animal ecosystem engineers are underappreciated as an agent of resistance and recovery for aquatic communities experiencing changes in sediment loads and hydrologic regimes.
Reeds diesel engine troubleshooting handbook

CERN Document Server

Pickthall, Barry

2013-01-01

Most diesel engines will develop a problem at some point in their lives, but armed with the right knowledge a skipper needn't worry. The Reeds Diesel Engine Troubleshooting Handbook is a compact, pocket-sized guide to finding solutions to all of the most common engine problems, and many of the less common ones too. The perfect format for quick reference on board, this book will help skippers fix troublesome engines themselves, avoiding costly engineer fees if the problem is simple to sort out, or enabling an emergency patch-up for a more serious problem until they can get back to port. Each to
Links between early baseline cortisol, attachment classification, and problem behaviors: A test of differential susceptibility versus diathesis-stress.

Science.gov (United States)

Fong, Michelle C; Measelle, Jeffrey; Conradt, Elisabeth; Ablow, Jennifer C

2017-02-01

The purpose of the current study was to predict concurrent levels of problem behaviors from young children's baseline cortisol and attachment classification, a proxy for the quality of caregiving experienced. In a sample of 58 children living at or below the federal poverty threshold, children's baseline cortisol levels, attachment classification, and problem behaviors were assessed at 17 months of age. We hypothesized that an interaction between baseline cortisol and attachment classification would predict problem behaviors above and beyond any main effects of baseline cortisol and attachment. However, based on limited prior research, we did not predict whether or not this interaction would be more consistent with diathesis-stress or differential susceptibility models. Consistent with diathesis-stress theory, the results indicated no significant differences in problem behavior levels among children with high baseline cortisol. In contrast, children with low baseline cortisol had the highest level of problem behaviors in the context of a disorganized attachment relationship. However, in the context of a secure attachment relationship, children with low baseline cortisol looked no different, with respect to problem behavior levels, then children with high cortisol levels. These findings have substantive implications for the socioemotional development of children reared in poverty. Copyright © 2017 Elsevier Inc. All rights reserved.
Work stress and subsequent risk of internet addiction among information technology engineers in Taiwan.

Science.gov (United States)

Chen, Sung-Wei; Gau, Susan Shur-Fen; Pikhart, Hynek; Peasey, Anne; Chen, Shih-Tse; Tsai, Ming-Chen

2014-08-01

Work stress, as defined by the Demand-Control-Support (DCS) model and the Effort-Reward Imbalance (ERI) model, has been found to predict risks for depression, anxiety, and substance addictions, but little research is available on work stress and Internet addiction. The aims of this study are to assess whether the DCS and ERI models predict subsequent risks of Internet addiction, and to examine whether these associations might be mediated by depression and anxiety. A longitudinal study was conducted in a sample (N=2,550) of 21-55 year old information technology engineers without Internet addiction. Data collection included questionnaires covering work stress, demographic factors, psychosocial factors, substance addictions, Internet-related factors, depression and anxiety at wave 1, and the Internet Addiction Test (IAT) at wave 2. Ordinal logistic regression was used to assess the associations between work stress and IAT; path analysis was adopted to evaluate potentially mediating roles of depression and anxiety. After 6.2 months of follow-up, 14.0% of subjects became problematic Internet users (IAT 40-69) and 4.1% pathological Internet users (IAT 70-100). Job strain was associated with an increased risk of Internet addiction (odds ratio [OR] of having a higher IAT outcome vs. a lower outcome was 1.53); high work social support reduced the risk of Internet addiction (OR=0.62). High ER ratio (OR=1.61) and high overcommitment (OR=1.68) were associated with increased risks of Internet addiction. Work stress defined by the DCS and ERI models predicted subsequent risks of Internet addiction.
Collaborative-Large scale Engineering Assessment Networks for Environmental Research: The Overview

Science.gov (United States)

Moo-Young, H.

2004-05-01

A networked infrastructure for engineering solutions and policy alternatives is necessary to assess, manage, and protect complex, anthropogenic ally stressed environmental resources effectively. Reductionist and discrete disciplinary methodologies are no longer adequate to evaluate and model complex environmental systems and anthropogenic stresses. While the reductonist approach provides important information regarding individual mechanisms, it cannot provide complete information about how multiple processes are related. Therefore, it is not possible to make accurate predictions about system responses to engineering interventions and the effectiveness of policy options. For example, experts cannot agree on best management strategies for contaminated sediments in riverine and estuarine systems. This is due, in part to the fact that existing models do not accurately capture integrated system dynamics. In addition, infrastructure is not available for investigators to exchange and archive data, to collaborate on new investigative methods, and to synthesize these results to develop engineering solutions and policy alternatives. Our vision for the future is to create a network comprising field facilities and a collaboration of engineers, scientists, policy makers, and community groups. This will allow integration across disciplines, across different temporal and spatial scales, surface and subsurface geographies, and air sheds and watersheds. Benefits include fast response to changes in system health, real-time decision making, and continuous data collection that can be used to anticipate future problems, and to develop sound engineering solutions and management decisions. CLEANER encompasses four general aspects: 1) A Network of environmental field facilities instrumented for the acquisition and analysis of environmental data; 2) A Virtual Repository of Data and information technology for engineering modeling, analysis and visualization of data, i.e. an environmental
Engineer Ethics

International Nuclear Information System (INIS)

Lee, Dae Sik; Kim, Yeong Pil; Kim, Yeong Jin

2003-03-01

This book tells of engineer ethics such as basic understanding of engineer ethics with history of engineering as a occupation, definition of engineering and specialized job and engineering, engineer ethics as professional ethics, general principles of ethics and its limitation, ethical theory and application, technique to solve the ethical problems, responsibility, safety and danger, information engineer ethics, biotechnological ethics like artificial insemination, life reproduction, gene therapy and environmental ethics.
Social problem solving strategies and posttraumatic stress disorder in the aftermath of intimate partner violence.

Science.gov (United States)

Reich, Catherine M; Blackwell, Náthali; Simmons, Catherine A; Beck, J Gayle

2015-05-01

Social factors are often associated with the development or maintenance of posttraumatic stress disorder (PTSD) in the aftermath of interpersonal traumas. However, social problem solving strategies have received little attention. The current study explored the role of social problem solving styles (i.e., rational approaches, impulsive/careless strategies, or avoidance strategies) as intermediary variables between abuse exposure and PTSD severity among intimate partner violence survivors. Avoidance problem solving served as an intermediating variable for the relationship between three types of abuse and PTSD severity. Rational and impulsive/careless strategies were not associated with abuse exposure. These findings extend the current understanding of social problem solving among interpersonal trauma survivors and are consistent with more general avoidance coping research. Future research might examine whether avoidance problem solving tends to evolve in the aftermath of trauma or whether it represents a longstanding risk factor for PTSD development. Published by Elsevier Ltd.
Linguistic Engineering and Linguistic of Engineering: Adaptation of Linguistic Paradigm for Circumstance of Engineering Epoch

OpenAIRE

Natalya Halina

2014-01-01

The article is devoted to the problems of linguistic knowledge in the Engineering Epoch. Engineering Epoch is the time of adaptation to the information flows by knowledge management, The system of adaptation mechanisms is connected with linguistic and linguistic technologies, forming in new linguistic patterns Linguistic Engineering and Linguistic of Engineering.
An interdisciplinary complex problem as a starting point for learning: Impact of the PBL method in second-year Environmental engineering students

Directory of Open Access Journals (Sweden)

E. Saez de Camara

2015-09-01

Full Text Available Three courses of the second year degree in Environmental Engineering (Geology and Pedology, Ecology and Economics and Business Administration have been remodeled using the Problem-Based Learning methodology. The proposed problem is a real-life and integrative problem related to their specialization which must be solved in these three courses at the same time. The results reveal that during this experience students were considerably more active, cooperative and involved, and the success rate doubled that of similar engineering courses of the Faculty. Regarding students’ opinion, it should be emphasized that they perceive that this method is functional and encouraging. A high percentage of the students describe the experience as positive or very positive. Additionally, they stated that the Problem-Based Learning promoted the development of skills that, in their own view, are essential for their career, such as teamwork and communication.
Teaching problem solving: Don't forget the problem solver(s)

Science.gov (United States)

Ranade, Saidas M.; Corrales, Angela

2013-05-01

The importance of intrapersonal and interpersonal intelligences has long been known but educators have debated whether to and how to incorporate those topics in an already crowded engineering curriculum. In 2010, the authors used the classroom as a laboratory to observe the usefulness of including selected case studies and exercises from the fields of neurology, artificial intelligence, cognitive sciences and social psychology in a new problem-solving course. To further validate their initial findings, in 2012, the authors conducted an online survey of engineering students and engineers. The main conclusion is that engineering students will benefit from learning more about the impact of emotions, culture, diversity and cognitive biases when solving problems. Specifically, the work shows that an augmented problem-solving curriculum needs to include lessons on labelling emotions and cognitive biases, 'evidence-based' data on the importance of culture and diversity and additional practice on estimating conditional probability.
X-ray and neutron diffraction determination of residual stresses in a pressed and welded component

International Nuclear Information System (INIS)

Albertini, G.; Broda, M.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.

1999-01-01

Complete text of publication follows. Problems connected with welding and pressing are very important in mechanical design, as these processed create microstructural alterations and internal stresses in the material that cannot be neglected. A pressing steel (FEP13) machine element is considered, designed to support a scooter engine. Two kinds of fatigue are to be supported by the component during operation: high loads at low frequency, due to the interaction of the scooter with the soil and low loads at high frequency due to the engine. The knowledge of the residual stress field occurring before operation is fundamental in order to perform theoretical predictions of the stress state during operation, and also to determine the loads to be used in fatigue tests which the component will be submitted to. The results of X-ray and neutron experiments are presented, carried out across a 'critical' weld in the component. (author)
The Effectiveness of Mentoring Youth with Externalizing and Internalizing Behavioral Problems on Youth Outcomes and Parenting Stress: A Meta-Analysis

Science.gov (United States)

La Valle, Chelsea

2015-01-01

Parents of children with significant externalizing and internalizing behavioral problems habitually report greater parenting stress compared to parents of children without these challenges. One avenue to alleviate parenting stress and ameliorate youth outcomes is youth mentoring, which includes a supportive adult paired with a child with the…
Effects of stress management training and problem solving on quality of life and life expectancy among infertile women

Directory of Open Access Journals (Sweden)

Mohammad Reza Zarbakhsh Bahri

2013-08-01

Full Text Available Introduction: This study aims to evaluate the effectiveness of stress management training and problem-solving training on quality of life and life expectancy of infertile women was conducted.Material and Methods: The method of this study was experimental with pretest – posttest design with a control group. population of 400 infertile women who referred to infertility center in Rasht were randomized to 250 of them were selected and the quality of life and life expectancy of the study were the 45 members of the quality of life and life expectancy lower were more randomly in three groups of 15 people, including two experimental groups and one control group were replaced. Each experimental groups were trained for 10 sessions of 90 minutes, respectively, stress management and problem-solving. Upon completion of the training program, participants were assessed again.Results: The result of present study showed that there was a significant difference between the experimental groups and control group in the scores of quality of life and life expectancy (p0.05.Conclusion: Stress management and problem solving training were effective on life expectancy and quality of life of infertile women but there was no significant difference between the effectiveness of these two methods on life expectancy and quality of life of infertile women.

Teaching ethics to engineers: ethical decision making parallels the engineering design process.

Science.gov (United States)

Bero, Bridget; Kuhlman, Alana

2011-09-01

In order to fulfill ABET requirements, Northern Arizona University's Civil and Environmental engineering programs incorporate professional ethics in several of its engineering courses. This paper discusses an ethics module in a 3rd year engineering design course that focuses on the design process and technical writing. Engineering students early in their student careers generally possess good black/white critical thinking skills on technical issues. Engineering design is the first time students are exposed to "grey" or multiple possible solution technical problems. To identify and solve these problems, the engineering design process is used. Ethical problems are also "grey" problems and present similar challenges to students. Students need a practical tool for solving these ethical problems. The step-wise engineering design process was used as a model to demonstrate a similar process for ethical situations. The ethical decision making process of Martin and Schinzinger was adapted for parallelism to the design process and presented to students as a step-wise technique for identification of the pertinent ethical issues, relevant moral theories, possible outcomes and a final decision. Students had greatest difficulty identifying the broader, global issues presented in an ethical situation, but by the end of the module, were better able to not only identify the broader issues, but also to more comprehensively assess specific issues, generate solutions and a desired response to the issue.
The role of failure/problems in engineering: A commentary of failures experienced - lessons learned

Science.gov (United States)

Ryan, R. S.

1992-03-01

The written version of a series of seminars given to several aerospace companies and three NASA centers are presented. The results are lessons learned through a study of the problems experienced in 35 years of engineering. The basic conclusion is that the primary cause of problems has not been mission technologies, as important as technology is, but the neglect of basic principles. Undergirding this is the lack of a systems focus from determining requirements through design, verification, and operations phases. Many of the concepts discussed are fundamental to total quality management (TQM) and can be used to augment this product enhanced philosophy. Fourteen principles are addressed with problems experienced and are used as examples. Included is a discussion of the implication of constraints, poorly defined requirements, and schedules. Design guidelines, lessons learned, and future tasks are listed. Two additional sections are included that deal with personal lessons learned and thoughts on future thrusts (TQM).
The role of failure/problems in engineering: A commentary of failures experienced - lessons learned

Science.gov (United States)

Ryan, R. S.

1992-01-01

The written version of a series of seminars given to several aerospace companies and three NASA centers are presented. The results are lessons learned through a study of the problems experienced in 35 years of engineering. The basic conclusion is that the primary cause of problems has not been mission technologies, as important as technology is, but the neglect of basic principles. Undergirding this is the lack of a systems focus from determining requirements through design, verification, and operations phases. Many of the concepts discussed are fundamental to total quality management (TQM) and can be used to augment this product enhanced philosophy. Fourteen principles are addressed with problems experienced and are used as examples. Included is a discussion of the implication of constraints, poorly defined requirements, and schedules. Design guidelines, lessons learned, and future tasks are listed. Two additional sections are included that deal with personal lessons learned and thoughts on future thrusts (TQM).
Factors affecting employee attrition among engineers and non-engineers in manufacturing industry

Directory of Open Access Journals (Sweden)

Bhardwaj, Shikha

2017-12-01

Full Text Available Almost every industry nowadays is badly affected by attrition. Retention of talented employees is the biggest problem faced by India Incorporation. In order to gather more insights on the talent crunch, the undertaken study was conducted on technical and non-technical jobs in manufacturing sector in Delhi NCR. Research has identified three major factors – Salary, Boss and Stress in the jobs after conducted interviews with around 50 technical and non-technical respondents. A set of questions were prepared and send to 120 employee but only 75 responded. The study shows a strong relationship between type of job and factors of attrition. Chi-square test clearly states strong relationship among two. Thus, any change in one will affect the other also. At the same time other important outcomes were that for technical jobs salary is the most important factor whereas non-technical Boss is the factor. Out 75, 63 were engineer and rest were non-engineer. The research can be further done to understand factors of attrition with other demographic variable.
Solving Some Special Cases of Monomial Ratio Equations Appearing Frequently in Physical and Engineering Problems

Directory of Open Access Journals (Sweden)

Enrique Castillo

2016-01-01

Full Text Available We first show that monomial ratio equations are not only very common in Physics and Engineering, but the natural type of equations in many practical problems. More precisely, in the case of models involving scale variables if the used formulas are not of this type they are not physically valid. The consequence is that when estimating the model parameters we are faced with systems of monomial ratio equations that are nonlinear and difficult to solve. In this paper, we provide an original algorithm to obtain the unique solutions of systems of equations made of linear combinations of monomial ratios whose coefficient matrix has a proper null space with low dimension that permits solving the problem in a simple way. Finally, we illustrate the proposed methods by their application to two practical problems from the hydraulic and structural fields.
Measurement of the residual stress distribution in a thick pre-stretched aluminum plate

Science.gov (United States)

Yuan, S. X.; Li, X. Q.; M, S.; Zhang, Y. C.; Gong, Y. D.

2008-12-01

Thick pre-stretched aluminum alloy plates are widely used in aircraft, while machining distortion caused by initial residual stress release in thick plates is a common and serious problem. To reduce the distortion, the residual stress distribution in thick plate must be measured. According to the characteristics of the thick pre-stretched aluminum alloy plate, based the elastic mechanical theory, this article deduces the modified layer-removal strain method adapting two different strain situations, which are caused by tensile and compressive stress. To validate this method, the residual stresses distribution along the thick direction of plate 2D70T351 is measured by this method, it is shown that the new method deduced in this paper is simple and accurate, and is very useful in engineering.
Effects of cognitive-behavioral therapy on improving anxiety symptoms, behavioral problems and parenting stress in Taiwanese children with anxiety disorders and their mothers.

Science.gov (United States)

Yen, Cheng-Fang; Chen, Yu-Min; Cheng, Jen-Wen; Liu, Tai-Ling; Huang, Tzu-Yu; Wang, Peng-Wei; Yang, Pinchen; Chou, Wen-Jiun

2014-06-01

The aims of this intervention study were to examine the effects of individual cognitive-behavioral therapy (CBT) based on the modified Coping Cat Program on improving anxiety symptoms and behavioral problems in Taiwanese children with anxiety disorders and parenting stress perceived by their mothers. A total of 24 children with anxiety disorders in the treatment group completed the 17-session individual CBT based on the modified Coping Cat Program, and 26 children in the control group received the treatment as usual intervention. The Taiwanese version of the MASC (MASC-T), the Child Behavior Checklist for Ages 6-18 (CBCL/6-18) and the Chinese version of the Parenting Stress Index (C-PSI) were applied to assess the severities of anxiety symptoms, behavioral problems and parenting stress, respectively. The effects of CBT on improving anxiety symptoms, behavioral problems and parenting stress were examined by using linear mixed-effect model with maximum likelihood estimation. The results indicated that the CBT significantly improved the severities of MASC-T Physical Symptoms and Social Anxiety subscales, CBCL/6-18 DSM-oriented Anxiety Problem subscale, and C-PSI Child domains Mood and Adaptability subscales. Individual CBT based on the modified Coping Cat Program can potentially improve anxiety symptoms in Taiwanese children with anxiety disorders and some child domains of parenting stress perceived by their mothers.
Line roughness improvements on self-aligned quadruple patterning by wafer stress engineering

Science.gov (United States)

Liu, Eric; Ko, Akiteru; Biolsi, Peter; Chae, Soo Doo; Hsieh, Chia-Yun; Kagaya, Munehito; Lee, Choongman; Moriya, Tsuyoshi; Tsujikawa, Shimpei; Suzuki, Yusuke; Okubo, Kazuya; Imai, Kiyotaka

2018-04-01

In integrated circuit and memory devices, size shrinkage has been the most effective method to reduce production cost and enable the steady increment of the number of transistors per unit area over the past few decades. In order to reduce the die size and feature size, it is necessary to minimize pattern formation in the advance node development. In the node of sub-10nm, extreme ultra violet lithography (EUV) and multi-patterning solutions based on 193nm immersionlithography are the two most common options to achieve the size requirement. In such small features of line and space pattern, line width roughness (LWR) and line edge roughness (LER) contribute significant amount of process variation that impacts both physical and electrical performances. In this paper, we focus on optimizing the line roughness performance by using wafer stress engineering on 30nm pitch line and space pattern. This pattern is generated by a self-aligned quadruple patterning (SAQP) technique for the potential application of fin formation. Our investigation starts by comparing film materials and stress levels in various processing steps and material selection on SAQP integration scheme. From the cross-matrix comparison, we are able to determine the best stack of film selection and stress combination in order to achieve the lowest line roughness performance while obtaining pattern validity after fin etch. This stack is also used to study the step-by-step line roughness performance from SAQP to fin etch. Finally, we will show a successful patterning of 30nm pitch line and space pattern SAQP scheme with 1nm line roughness performance.
Associations Between Stressful Events and Self-Reported Mental Health Problems Among Non-Western Immigrants in Denmark

DEFF Research Database (Denmark)

Singhammer, John; Bancila, Delia

2011-01-01

The aim of the present paper is to investigate the relationships of stressful events with self-reported mental health problems in the general population, comparing non-western immigrants with Danish nationals. 11.500 individuals aged 18-64 years from eight ethnic groups were invited to participat...
Eddy current spectroscopy for near-surface residual stress profiling in surface treated nonmagnetic engine alloys

Science.gov (United States)

Abu-Nabah, Bassam A.

Recent research results indicated that eddy current conductivity measurements can be exploited for nondestructive evaluation of near-surface residual stresses in surface-treated nickel-base superalloy components. Most of the previous experimental studies were conducted on highly peened (Almen 10-16A) specimens that exhibit harmful cold work in excess of 30% plastic strain. Such high level of cold work causes thermo-mechanical relaxation at relatively modest operational temperatures; therefore the obtained results were not directly relevant to engine manufacturers and end users. The main reason for choosing peening intensities in excess of recommended normal levels was that in low-conductivity engine alloys the eddy current penetration depth could not be forced below 0.2 mm without expanding the measurements above 10 MHz which is beyond the operational range of most commercial eddy current instruments. As for shot-peened components, it was initially felt that the residual stress effect was more difficult to separate from cold work, texture, and inhomogeneity effects in titanium alloys than in nickel-base superalloys. In addition, titanium alloys have almost 50% lower electric conductivity than nickel-base superalloys; therefore require proportionally higher inspection frequencies, which was not feasible until our recent breakthrough in instrument development. Our work has been focused on six main aspects of this continuing research, namely, (i) the development of an iterative inversion technique to better retrieve the depth-dependent conductivity profile from the measured frequency-dependent apparent eddy current conductivity (AECC), (ii) the extension of the frequency range up to 80 MHz to better capture the peak compressive residual stress in nickel-base superalloys using a new eddy current conductivity measuring system, which offers better reproducibility, accuracy and measurement speed than the previously used conventional systems, (iii) the lift-off effect on
A new undergraduate course: Problems in nuclear engineering

International Nuclear Information System (INIS)

Larsen, Edward W.

2011-01-01

During the past five years, a new third-year undergraduate nuclear engineering course has been developed and taught at the University of Michigan. The course was created to correct certain deficiencies in the undergraduate nuclear engineering curriculum. Here we discuss the origins of the new course and our experience with it. (author)
Effects of the KEEP Foster Parent Intervention on Child and Sibling Behavior Problems and Parental Stress During a Randomized Implementation Trial.

Science.gov (United States)

Price, Joseph M; Roesch, Scott; Walsh, Natalia E; Landsverk, John

2015-07-01

Children in foster care are at risk for externalizing behavior problems, which can in turn increase the risk of changes in foster care placement. The KEEP (Keeping Foster Parents Trained and Supported) foster parent training intervention was designed to equip foster parents with strategies for managing externalizing behavior problems. The primary goals of this investigation were to (a) examine the effectiveness of the KEEP intervention in reducing child behavior problems, as delivered by a community agency; (b) determine if the effects of the KEEP intervention generalize to more than one child in the same home; and (c) examine the effectiveness of the KEEP intervention in reducing parental stress associated with child behavior problems. The data from 335 foster and kinship families with children between the ages of 5 and 12 years were analyzed to address these objectives. Families were randomly assigned to the intervention or control condition. The results indicated that the KEEP intervention was effective in reducing child behavior problems when delivered by a community agency. These results expanded prior research on the KEEP intervention, revealing that the intervention was effective in reducing the behavior problems of more than one child in the same household and in reducing parental stress levels associated with the behavioral issues of the focal child. Thus, the KEEP intervention model holds promise for reducing the behavior problems of children in foster care and reducing stress levels of foster and kinship caregivers as it is disseminated and implemented within similar child welfare settings.
Report to NASA Committee on Aircraft Operating Problems Relative to Aviation Safety Engineering and Research Activities

Science.gov (United States)

1963-01-01

The following report highlights some of the work accomplished by the Aviation Safety Engineering and Research Division of the Flight Safety Foundations since the last report to the NASA Committee on Aircraft Operating Problems on 22 May 1963. The information presented is in summary form. Additional details may be provided upon request of the reports themselves may be obtained from AvSER.
Organizational stress and individual strain: A social-psychological study of risk factors in coronary heart disease among administrators, engineers, and scientists

Science.gov (United States)

Caplan, R. D.

1971-01-01

It is hypothesized that organizational stresses, such as high quantitative work load, responsibility for persons, poor relations with role senders, and contact with alien organizational territories, may be associated with high levels of psychological and physiological strain which are risk factors in coronary heart disease. It is further hypothesized that persons with coronary-prone Type A personality characteristics are most likely to exhibit strain under conditions of organizational stress. Measures of these stresses, personality traits, and strains were obtained from 205 male NASA administrators, engineers, and scientists. Type A personality measures included sense of time urgency, persistence, involved striving, leadership, and preference for competitive and environmentally overburdening situations.
Heat stress intervention research in construction: gaps and recommendations.

Science.gov (United States)

Yang, Yang; Chan, Albert Ping-Chuen

2017-06-08

Developing heat stress interventions for construction workers has received mounting concerns in recent years. However, limited efforts have been exerted to elaborate the rationale, methodology, and practicality of heat stress intervention in the construction industry. This study aims to review previous heat stress intervention research in construction, to identify the major research gaps in methodological issues, and to offer detailed recommendations for future studies. A total of 35 peer-reviewed journal papers have been identified to develop administrative, environmental or personal engineering interventions to safeguard construction workers. It was found that methodological limitations, such as arbitrary sampling methods and unreliable instruments, could be the major obstacle in undertaking heat stress intervention research. To bridge the identified research gaps, this study then refined a research framework for conducting heat stress intervention studies in the construction industry. The proposed research strategy provides researchers and practitioners with fresh insights into expanding multidisciplinary research areas and solving practical problems in the management of heat stress. The proposed research framework may foster the development of heat stress intervention research in construction, which further aids researchers, practitioners, and policymakers in formulating proper intervention strategies.
Associations between Parental Anxiety/Depression and Child Behavior Problems Related to Autism Spectrum Disorders: The Roles of Parenting Stress and Parenting Self-Efficacy

OpenAIRE

Rezendes, Debra L.; Scarpa, Angela

2011-01-01

Parents of children with autism spectrum disorders (ASDs) have been shown to experience increases in stress, depression, and anxiety, which are also associated with child behavior problems related to ASDs. Literature-examining potential mechanisms that underlie the relationship of child behavior problems and parental anxiety/depression in this population are scarce. The current study sought to examine the roles of parenting stress and parenting self-efficacy as mediators between child behavio...
Pathogenesis-related proteins and peptides as promising tools for engineering plants with multiple stress tolerance.

Science.gov (United States)

Ali, Sajad; Ganai, Bashir Ahmad; Kamili, Azra N; Bhat, Ajaz Ali; Mir, Zahoor Ahmad; Bhat, Javaid Akhter; Tyagi, Anshika; Islam, Sheikh Tajamul; Mushtaq, Muntazir; Yadav, Prashant; Rawat, Sandhya; Grover, Anita

Pathogenesis-related (PR) proteins and antimicrobial peptides (AMPs) are a group of diverse molecules that are induced by phytopathogens as well as defense related signaling molecules. They are the key components of plant innate immune system especially systemic acquired resistance (SAR), and are widely used as diagnostic molecular markers of defense signaling pathways. Although, PR proteins and peptides have been isolated much before but their biological function remains largely enigmatic despite the availability of new scientific tools. The earlier studies have demonstrated that PR genes provide enhanced resistance against both biotic and abiotic stresses, which make them one of the most promising candidates for developing multiple stress tolerant crop varieties. In this regard, plant genetic engineering technology is widely accepted as one of the most fascinating approach to develop the disease resistant transgenic crops using different antimicrobial genes like PR genes. Overexpression of PR genes (chitinase, glucanase, thaumatin, defensin and thionin) individually or in combination have greatly uplifted the level of defense response in plants against a wide range of pathogens. However, the detailed knowledge of signaling pathways that regulates the expression of these versatile proteins is critical for improving crop plants to multiple stresses, which is the future theme of plant stress biology. Hence, this review provides an overall overview on the PR proteins like their classification, role in multiple stresses (biotic and abiotic) as well as in various plant defense signaling cascades. We also highlight the success and snags of transgenic plants expressing PR proteins and peptides. Copyright © 2018 Elsevier GmbH. All rights reserved.
Nature and Treatment of Comorbid Alcohol Problems and Post Traumatic Stress Disorder Among American Military Personnel and Veterans.

Science.gov (United States)

Allen, John P; Crawford, Eric F; Kudler, Harold

2016-01-01

Many service members and veterans seeking treatment for alcohol problems also have post-traumatic stress disorder (PTSD). This article considers the effectiveness of treating alcohol problems and PTSD simultaneously. The authors begin by summarizing the extent of excessive alcohol use among military service members and veterans. They then explore the relationship between combat exposure and subsequent alcohol use; identify and briefly describe evidence-based treatments for alcohol problems and PTSD, separately; and review research on the effects of single treatments for both PTSD symptoms and alcohol use.
DEM GPU studies of industrial scale particle simulations for granular flow civil engineering applications

Science.gov (United States)

Pizette, Patrick; Govender, Nicolin; Wilke, Daniel N.; Abriak, Nor-Edine

2017-06-01

The use of the Discrete Element Method (DEM) for industrial civil engineering industrial applications is currently limited due to the computational demands when large numbers of particles are considered. The graphics processing unit (GPU) with its highly parallelized hardware architecture shows potential to enable solution of civil engineering problems using discrete granular approaches. We demonstrate in this study the pratical utility of a validated GPU-enabled DEM modeling environment to simulate industrial scale granular problems. As illustration, the flow discharge of storage silos using 8 and 17 million particles is considered. DEM simulations have been performed to investigate the influence of particle size (equivalent size for the 20/40-mesh gravel) and induced shear stress for two hopper shapes. The preliminary results indicate that the shape of the hopper significantly influences the discharge rates for the same material. Specifically, this work shows that GPU-enabled DEM modeling environments can model industrial scale problems on a single portable computer within a day for 30 seconds of process time.
Development of a Positive Youth Development Program: Promoting the Mental Health of Stressful Adolescents Using Principles of Problem Solving Therapy

Directory of Open Access Journals (Sweden)

Daniel T.L. Shek

2006-01-01

Full Text Available This paper outlines the proposal for the development, implementation, and evaluation of a positive youth development program that attempts to promote the mental health of stressful Chinese adolescents using principles of Problem Solving Therapy (PST. There are two general aims of PST: to help clients identify life difficulties and resolve them, as well as to teach them skills on how to deal with future problems. The proposed project will utilize the principles of PST as the guiding framework to run two mental health promotion courses for adolescents who are experiencing disturbing stressful responses and students who want to improve their stress management style. Both objective and subjective outcome evaluation strategies will be carried out to assess the effectiveness of the intervention to promote the psychological well-being in adolescents who are experiencing stress. A related sample proposal is described that can give social workers some insight on how to prepare a proposal for developing the Tier 2 Program of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programs.

Mine engineering and ventilation problems unique to the control of radon daughters

International Nuclear Information System (INIS)

Rock, R.L.

1975-01-01

Quality and quantity of ventilation are the two interrelated but key factors in any radon-daughter control programme. The better the intake air quality (little or no contamination from radon and its daughters), the less are the total air requirements for ventilation of active mining areas. Engineering principles for quantity distribution of air through underground working areas are straightforward and the formulae and theories governing forced ventilation are not within the scope of this paper. Rather, this paper discusses the principal methods of utilizing mine planning to facilitate radon-daughter control and also treats the more subtle features of mine ventilation which are especially critical in the ventilation of mines where radon gas constitutes an environmental contamination problem. (author)
Developing Curriculum of Nuclear Civil Engineering Degree Programme at Graduate Level

International Nuclear Information System (INIS)

Iqbal, J.

2016-01-01

Full text: The paper suggests the introduction of a new degree, namely nuclear civil engineering at graduate level for better utilization of civil engineers in nuclear power plant (NPP) design and construction. At present, both nuclear engineering and civil engineering degrees are offered at undergraduate and graduate levels in numerous renowned universities of the world. However, when a civil engineer, even after completion of nuclear engineering at postgraduate level, undertakes an assignment related to NPP design, he comes across various problems which are not covered in the present curricula. For instance, NPPs’ siting issues, design of pre-stressed concrete containment against loads of loss of coolant accident (LOCA), various impulsive and impactive loads (e.g., detonations, aircraft crash analysis, etc.) and shielding calculations are some of the core issues during nuclear power plant design. The paper highlights the importance of introduction of nuclear civil engineering degree at the graduate level. Besides, the contents of the proposed course work have also been discussed. Keeping in view the fact that, currently, no such degree is offered in any university of the world, the paper explores useful avenues to human resource development for introducing and expanding nuclear power programmes. (author
An extension of the maximum principle to dimensional systems and its application in nuclear engineering problems

International Nuclear Information System (INIS)

Gilai, D.

1976-01-01

The Maximum Principle deals with optimization problems of systems, which are governed by ordinary differential equations, and which include constraints on the state and control variables. The development of nuclear engineering confronted the designers of reactors, shielding and other nuclear devices with many requests of optimization and savings and it was straight forward to use the Maximum Principle for solving optimization problems in nuclear engineering, in fact, it was widely used both structural concept design and dynamic control of nuclear systems. The main disadvantage of the Maximum Principle is that it is suitable only for systems which may be described by ordinary differential equations, e.g. one dimensional systems. In the present work, starting from the variational approach, the original Maximum Principle is extended to multidimensional systems, and the principle which has been derived, is of a more general form and is applicable to any system which can be defined by linear partial differential equations of any order. To check out the applicability of the extended principle, two examples are solved: the first in nuclear shield design, where the goal is to construct a shield around a neutron emitting source, using given materials, so that the total dose outside of the shielding boundaries is minimized, the second in material distribution design in the core of a power reactor, so that the power peak is minimised. For the second problem, an iterative method was developed. (B.G.)
Investigations of oxidative stress effects and their mechanisms in rat brain after systemic administration of ceria engineered nanomaterials

Science.gov (United States)

Hardas, Sarita S.

Advancing applications of engineered nanomaterials (ENM) in various fields create the opportunity for intended (e.g. drug and gene delivery) or unintended (e.g. occupational and environmental) exposure to ENM. However, the knowledge of ENM-toxicity is lagging behind their application development. Understanding the ENM hazard can help us to avoid potential human health problems associated with ENM applications as well as to increase their public acceptance. Ceria (cerium [Ce] oxide) ENM have many current and potential commercial applications. Beyond the traditional use of ceria as an abrasive, the scope of ceria ENM applications now extends into fuel cell manufacturing, diesel fuel additives and for therapeutic intervention as a putative antioxidant. However, the biological effects of ceria ENM exposure have yet to be fully defined. Both pro-and anti-oxidative effects of ceria ENM exposure are repeatedly reported in literature. EPA, NIEHS and OECD organizations have nominated ceria for its toxicological evaluation. All these together gave us the impetus to examine the oxidative stress effects of ceria ENM after systemic administration. Induction of oxidative stress is one of the primary mechanisms of ENM toxicity. Oxidative stress plays an important role in maintaining the redox homeostasis in the biological system. Increased oxidative stress, due to depletion of antioxidant enzymes or molecules and / or due to increased production of reactive oxygen (ROS) or nitrogen (RNS) species may lead to protein oxidation, lipid peroxidation and/or DNA damage. Increased protein oxidation or lipid peroxidation together with antioxidant protein levels and activity can serve as markers of oxidative stress. To investigate the oxidative stress effects and the mechanisms of ceria-ENM toxicity, fully characterized ceria ENM of different sizes (˜ 5nm, 15nm, 30nm, 55nm and nanorods) were systematically injected into rats intravenously in separate experiments. Three brain regions
Engineering Background: Modern Formats and Challenges of Conceptual Engineering

Science.gov (United States)

Khamidullina, A. F.; Kuzmina, M. A.; Khusnutdinova, E. M.; Konakhina, I. A.

2017-09-01

This paper describes the analysis of problems and development perspectives of engineering education in our and other countries. Special attention is given to modern formats of education that motivate creative efforts of engineers-to-be as well as issues of conceptual engineering taking the challenges of modernity into account.
Working towards a scalable model of problem-based learning instruction in undergraduate engineering education

Science.gov (United States)

Mantri, Archana

2014-05-01

The intent of the study presented in this paper is to show that the model of problem-based learning (PBL) can be made scalable by designing curriculum around a set of open-ended problems (OEPs). The detailed statistical analysis of the data collected to measure the effects of traditional and PBL instructions for three courses in Electronics and Communication Engineering, namely Analog Electronics, Digital Electronics and Pulse, Digital & Switching Circuits is presented here. It measures the effects of pedagogy, gender and cognitive styles on the knowledge, skill and attitude of the students. The study was conducted two times with content designed around same set of OEPs but with two different trained facilitators for all the three courses. The repeatability of results for effects of the independent parameters on dependent parameters is studied and inferences are drawn.
Multilevel Analysis Exploring the Links between Stress, Depression, and Sleep Problems among Two-Year College Students

Science.gov (United States)

Wallace, Deshira D.; Boynton, Marcella H.; Lytle, Leslie A.

2017-01-01

Objective: This study explored the association of stress and depression with a multidimensional sleep problems construct in a sample of 2-year college students. Participants: The sample consisted of 440 students enrolled in 2-year study from Fall 2011 to Fall 2013. Methods: Participants in an obesity prevention study completed surveys assessing…
Engineering Synechocystis PCC6803 for hydrogen production: influence on the tolerance to oxidative and sugar stresses.

Directory of Open Access Journals (Sweden)

Marcia Ortega-Ramos

Full Text Available In the prospect of engineering cyanobacteria for the biological photoproduction of hydrogen, we have studied the hydrogen production machine in the model unicellular strain Synechocystis PCC6803 through gene deletion, and overexpression (constitutive or controlled by the growth temperature. We demonstrate that the hydrogenase-encoding hoxEFUYH operon is dispensable to standard photoautotrophic growth in absence of stress, and it operates in cell defense against oxidative (H₂O₂ and sugar (glucose and glycerol stresses. Furthermore, we showed that the simultaneous over-production of the proteins HoxEFUYH and HypABCDE (assembly of hydrogenase, combined to an increase in nickel availability, led to an approximately 20-fold increase in the level of active hydrogenase. These novel results and mutants have major implications for those interested in hydrogenase, hydrogen production and redox metabolism, and their connections with environmental conditions.
Stress in piezoelectric hollow sphere with thermal gradient

International Nuclear Information System (INIS)

Saadatfar, M.; Rastgoo, A.

2008-01-01

The piezoelectric phenomenon has been exploited in science and engineering for decades. Recent advances in smart structures technology have led to a resurgence of interest in piezoelectricity, and in particular, in the solution of fundamental boundary value problems. In this paper, we develop an analytic solution to the axisymmetric problem of a radially polarized, spherically isotropic piezoelectric hollow sphere. The sphere is subjected to uniform internal pressure, or uniform external pressure, or both and thermal gradient. There is a constant thermal difference between its inner and outer surfaces. An analytic solution to the governing equilibrium equations (a coupled system of second-order ordinary differential equations) is obtained. On application of the boundary conditions, the problem is reduced to solving a system of linear algebraic equations. Finally, the stress distributions in the sphere are obtained numerically for two piezoceramics
Perspectives of ukrainian mechanical engineering development

OpenAIRE

Dyrda, E.; Schepetkova, A.; Galushko, O.

2013-01-01

Theses are devoted to problems and perspectives of Ukrainian mechanical engineering development. Role of mechanical engineering in national economy is described. Problems of mechanical engineering, such as losing the cometetive advantages, production decreasing, debts growing, ineffective assets structure, are investigated. Influence of European integration process on mechanical engineering enterprises is discussed.
Experimental stress analysis for determination of residual stresses and integrity monitoring of components and systems

International Nuclear Information System (INIS)

1993-01-01

For an analysis of the safety-related significance of residual stresses, mechanical, magnetic as well as ultrasonic and diffraction methods can be applied as testing methods. The results of an interlaboratory test concerning the experimental determination of residual stresses in a railway track are included. Further, questions are analyzed concerning the in-service inspections of components and systems with regard to their operational safety and life. Measurement methods are explained by examples from power plant engineering, nuclear power plant engineering, construction and traffic engineering as well as aeronautics. (DG) [de
Internal combustion engine cold-start efficiency: A review of the problem, causes and potential solutions

International Nuclear Information System (INIS)

Roberts, Andrew; Brooks, Richard; Shipway, Philip

2014-01-01

Highlights: • The sources of I.C. engine cold start efficiency are reviewed and quantified. • Potential solutions are reviewed and the benefit quantified together. • Potential conflicts between different engine sub-systems are discussed. • Fuel consumption benefits of up to 7% are observed during cold start. • Emission reductions of up to 40% during cold start are observed. - Abstract: Legislation on vehicle emissions continues to become more stringent in an effort to minimise the impact of internal combustion engines on the environment. One area of significant concern in this respect is that of the cold-start; the thermal efficiency of the internal combustion engine is significantly lower at cold-start than when the vehicle reaches steady state temperatures owing to sub-optimal lubricant and component temperatures. The drive for thermal efficiency (of both the internal combustion engine and of the vehicle as a whole) has led to a variety of solutions being trialled to assess their merits and effects on other vehicle systems during this warm-up phase (and implemented where appropriate). The approaches have a common theme of attempting to reduce energy losses so that systems and components reach their intended operating temperature range as soon as possible after engine start. In the case of the engine, this is primarily focused on the lubricant system. Lubricant viscosity is highly sensitive to temperature and the increased viscosity at low temperatures results in higher frictional and pumping losses than would be observed at the target operating temperature. The approaches used to tackle the problem include the use of phase change materials (to reduce the cool-down rate during a period following engine running) [1,2] and the use of thermal barrier coatings in an attempt to insulate the cylinder bore and prevent heat loss (thus increasing the amount of energy utilised as brake work [3]). A range of system alterations have also been trialled including
A comparison between Engin and Engin-X, a new diffractometer optimized for stress measurement

International Nuclear Information System (INIS)

Dann, J.A.; Daymond, M.R.; Edwards, L.; James, J.A.; Santisteban, J.R.

2004-01-01

Engineering diffractometers are used extensively by both engineers and materials scientists for the measurement of strain within polycrystalline materials, both metallic and ceramic. In the past neutron diffractometers have generally been built as 'all-purpose' instruments, with designs that are compromises, balancing competing requirements to measure the intensities, positions and widths of diffraction peaks simultaneously. In contrast the newly constructed diffractometer ENGIN-X was designed with the single aim of making engineering strain measurements; essentially the accurate measurement of polycrystalline lattice parameters, at a precisely determined position. Under this design philosophy, considerable performance improvements have been obtained compared to the existing instrument. This paper details the design philosophy of this instrument, including tuneable incident resolution, together with the approaches used to realise the performance required. The improved instrument performance is demonstrated here, with results obtained during the commissioning of ENGIN-X. These results include strain mapping experiments, and demonstrate the influence of resolution on required count times, and provide a direct comparison with measurements from the existing ENGIN instrument at ISIS
Reaction Control System Thruster Cracking Consultation: NASA Engineering and Safety Center (NESC) Materials Super Problem Resolution Team (SPRT) Findings

Science.gov (United States)

MacKay, Rebecca A.; Smith, Stephen W.; Shah, Sandeep R.; Piascik, Robert S.

2005-01-01

The shuttle orbiter s reaction control system (RCS) primary thruster serial number 120 was found to contain cracks in the counter bores and relief radius after a chamber repair and rejuvenation was performed in April 2004. Relief radius cracking had been observed in the 1970s and 1980s in seven thrusters prior to flight; however, counter bore cracking had never been seen previously in RCS thrusters. Members of the Materials Super Problem Resolution Team (SPRT) of the NASA Engineering and Safety Center (NESC) conducted a detailed review of the relevant literature and of the documentation from the previous RCS thruster failure analyses. It was concluded that the previous failure analyses lacked sufficient documentation to support the conclusions that stress corrosion cracking or hot-salt cracking was the root cause of the thruster cracking and lacked reliable inspection controls to prevent cracked thrusters from entering the fleet. The NESC team identified and performed new materials characterization and mechanical tests. It was determined that the thruster intergranular cracking was due to hydrogen embrittlement and that the cracking was produced during manufacturing as a result of processing the thrusters with fluoride-containing acids. Testing and characterization demonstrated that appreciable environmental crack propagation does not occur after manufacturing.
Interactive simulations as teaching tools for engineering mechanics courses

Science.gov (United States)

Carbonell, Victoria; Romero, Carlos; Martínez, Elvira; Flórez, Mercedes

2013-07-01

This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills.
Fundamentals of Structural Engineering

CERN Document Server

Connor, Jerome J

2013-01-01

Fundamentals of Structural Engineering provides a balanced, seamless treatment of both classic, analytic methods and contemporary, computer-based techniques for conceptualizing and designing a structure. The book’s principle goal is to foster an intuitive understanding of structural behavior based on problem solving experience for students of civil engineering and architecture who have been exposed to the basic concepts of engineering mechanics and mechanics of materials. Making it distinct from many other undergraduate textbooks, the authors of this text recognize the notion that engineers reason about behavior using simple models and intuition they acquire through problem solving. The approach adopted in this text develops this type of intuition by presenting extensive, realistic problems and case studies together with computer simulation, which allows rapid exploration of how a structure responds to changes in geometry and physical parameters. This book also: Emphasizes problem-based understanding of...
Sources of Stress and Coping Strategies among Undergraduate Medical Students Enrolled in a Problem-Based Learning Curriculum

Directory of Open Access Journals (Sweden)

Samira S. Bamuhair

2015-01-01

Full Text Available Background. Medical education is rated as one of the most difficult trainings to endure. Throughout their undergraduate years, medical students face numerous stressors. Coping with these stressors requires access to a variety of resources, varying from personal strengths to social support. We aimed to explore the perceived stress, stressors, and coping strategies employed by medical students studying in a problem-based learning curriculum. Methodology. This is a cross-sectional study of randomly selected medical students that explored demographics, perceived stress scale, sources of stress, and coping strategies. Results. Of the 378 medical students that participated in the study, males were 59.3% and females 40.7%. Nearly 53% of the students often felt stressed, and a third felt that they could not cope with stress. Over 82% found studying stressful and 64.3% were not sleeping well. Half of the students reported low self-esteem. Perceived stress scores were statistically significantly high for specific stressors of studying in general, worrying about future, interpersonal conflict, and having low self-esteem. Coping strategies that were statistically significantly applied more often were blaming oneself and being self-critical, seeking advice and help from others, and finding comfort in religion. Female students were more stressed than males but they employ more coping strategies as well. Conclusions. Stress is very common among medical students. Most of the stressors are from coursework and interpersonal relationships. Low self-esteem coupled with self-blame and self-criticism is quite common.
Economic Stress, Emotional Quality of Life, and Problem Behavior in Chinese Adolescents with and without Economic Disadvantage

Science.gov (United States)

Shek, Daniel T. L.

2005-01-01

The relationships between perceived economic stress (current economic hardship and future economic worry) and emotional quality of life (existential well-being, life satisfaction, self-esteem, sense of mastery, psychological morbidity) as well as problem behavior (substance abuse and delinquency) were examined in 1519 Chinese adolescents with and…
Association Between Caregiver Stress and Behavioral Problems in the Children of Incarcerated Fathers in Hong Kong.

Science.gov (United States)

Chui, Wing Hong

2016-10-01

Objectives Caregivers of children with incarcerated parents have received little attention in the literature, though they face unique incarceration-related challenges. General caregiver research has highlighted associations between caregiver distress and children's behavioral problems, even implying that the depressive tendencies of caregivers can be 'transmitted'. The current study investigated the applicability of this notion to caregivers responsible for children of incarcerated fathers. Methods Fifty-four female caregivers of children with incarcerated parents were recruited via collaboration with a non-governmental organization. Their levels of stress and depression were measured using questionnaires, as were the behavioral problems of children under their care. The relationships between the variables were examined. Results The results firstly suggest that these caregivers are vulnerable to psychological distress, with around 57 % of them suffering from borderline to severe depression. Obtained socio-demographic characteristics were not found to have any bearing on the psychosocial functioning of caregivers or children-rather, all psychosocial variables were interlinked, and further analyses revealed that the depression of caregivers mediated the relationship between their perceived stress and internalizing/externalizing behavioral problems of the child (β = .628 and β = .468 respectively), implicating depression as a mechanism via which adversity can be transferred from a caregiver to a child. Conclusions Increasing the focus on a caregiver's mental health may be an efficacious strategy in research and practice, perhaps by providing more support for caregivers and implementing joint caregiver-child interventions to more holistically alleviate problems in families affected by parental incarceration. Limitations of the current study and further recommendations are also discussed.
Applying Systems Engineering on Energy Challenges

NARCIS (Netherlands)

Safi, J.; Muller, G.; Bonnema, Gerrit Maarten

2012-01-01

Systems engineering is a discipline with methods and techniques to address complex problems. We want to study how Systems Engineering methods can help to address today's grand challenges, such as the energy problem. The first step is problem definition which aims at articulating the problem in its

Materials Science and Engineering |

Science.gov (United States)

Engineering? What Is Materials Science and Engineering? MSE combines engineering, physics and chemistry to solve problems in nanotechnology, biotechnology, information technology, energy, manufacturing, and more ,' which could replace steel. Materials Science and Mechanical Engineering Professors work together to
Example of answers to the problems of the 37th examination for the Chief Engineer of Nuclear Fuel. 2005

International Nuclear Information System (INIS)

Harada, Akio; Nakajima, Kunihisa; Yachi, Shigeyasu; Komuro, Yuichi; Kushita, Kouhei

2005-09-01

This report provides an example of answers to the problems of the 37th examination for the Chief Engineer of Nuclear Fuel. This examination was done as a national qualification in March 2005. Brief explanations or references are added to some answers. (author)
Engineering the path to higher-order thinking in elementary education: A problem-based learning approach for STEM integration

Science.gov (United States)

Rehmat, Abeera Parvaiz

As we progress into the 21st century, higher-order thinking skills and achievement in science and math are essential to meet the educational requirement of STEM careers. Educators need to think of innovative ways to engage and prepare students for current and future challenges while cultivating an interest among students in STEM disciplines. An instructional pedagogy that can capture students' attention, support interdisciplinary STEM practices, and foster higher-order thinking skills is problem-based learning. Problem-based learning embedded in the social constructivist view of teaching and learning (Savery & Duffy, 1995) promotes self-regulated learning that is enhanced through exploration, cooperative social activity, and discourse (Fosnot, 1996). This quasi-experimental mixed methods study was conducted with 98 fourth grade students. The study utilized STEM content assessments, a standardized critical thinking test, STEM attitude survey, PBL questionnaire, and field notes from classroom observations to investigate the impact of problem-based learning on students' content knowledge, critical thinking, and their attitude towards STEM. Subsequently, it explored students' experiences of STEM integration in a PBL environment. The quantitative results revealed a significant difference between groups in regards to their content knowledge, critical thinking skills, and STEM attitude. From the qualitative results, three themes emerged: learning approaches, increased interaction, and design and engineering implementation. From the overall data set, students described the PBL environment to be highly interactive that prompted them to employ multiple approaches, including design and engineering to solve the problem.
Analysis of a plane stress wave by the moving least squares method

Directory of Open Access Journals (Sweden)

Wojciech Dornowski

2014-08-01

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

National Research Council Canada - National Science Library

Muller, Siemon W; French, Hugh M; Nelson, Frederick E

2008-01-01

...), author of the first English-language book about perennially frozen ground.". "This book reads like a "how-to" manual for engineering personnel working in pioneering or primitive circumstances...
Work stress, worries, and pain interact synergistically with modelled traffic noise on cross-sectional associations with self-reported sleep problems

OpenAIRE

Kristiansen, Jesper; Persson, Roger; Björk, Jonas; Albin, Maria; Jakobsson, Kristina; Östergren, Per-Olof; Ardö, Jonas

2011-01-01

To examine the risk of sleep problems associated with work stress (job strain, job demands, and decision authority), worries and pain and to investigate the synergistic interaction between these factors and traffic noise. Sleep problems and predictor variables were assessed in a cross-sectional public health survey with 12,093 respondents. Traffic noise levels were assessed using modelled A-weighted energy equivalent traffic sound levels at the residence. The risk of sleep problems was modell...
Combustion Temperature Effect of Diesel Engine Convert to Compressed Natural Gas Engine

OpenAIRE

Semin; Abdul R. Ismail; Rosli A. Bakar

2009-01-01

Effect of combustion temperature in the engine cylinder of diesel engine convert to Compressed Natural Gas (CNG) engine was presents in this study. The objective of this study was to investigate the engine cylinder combustion temperature effect of diesel engine convert to CNG engine on variation engine speed. Problem statement: The hypothesis was that the lower performance of CNG engine was caused by the effect of lower in engine cylinder temperature. Are the CNG engine is lower cylinder temp...
I "Still" Wanna Be an Engineer! Women, Education and the Engineering Profession

Science.gov (United States)

Gill, Judith; Sharp, Rhonda; Mills, Julie; Franzway, Suzanne

2008-01-01

Women's low enrolment in post-school engineering degrees continues to be a problem for engineering faculties and the profession generally. A qualitative interview-based study of Australian women engineers across the range of engineering disciplines showed the relevance of success in math and science at school to their enrolling in engineering at…
Associations between work-related stress in late midlife, educational attainment, and serious health problems in old age: a longitudinal study with over 20 years of follow-up.

Science.gov (United States)

Nilsen, Charlotta; Andel, Ross; Fors, Stefan; Meinow, Bettina; Darin Mattsson, Alexander; Kåreholt, Ingemar

2014-08-27

People spend a considerable amount of time at work over the course of their lives, which makes the workplace important to health and aging. However, little is known about the potential long-term effects of work-related stress on late-life health. This study aims to examine work-related stress in late midlife and educational attainment in relation to serious health problems in old age. Data from nationally representative Swedish surveys were used in the analyses (n = 1,502). Follow-up time was 20-24 years. Logistic regressions were used to examine work-related stress (self-reported job demands, job control, and job strain) in relation to serious health problems measured as none, serious problems in one health domain, and serious problems in two or three health domains (complex health problems). While not all results were statistically significant, high job demands were associated with higher odds of serious health problems among women but lower odds of serious health problems among men. Job control was negatively associated with serious health problems. The strongest association in this study was between high job strain and complex health problems. After adjustment for educational attainment some of the associations became statistically nonsignificant. However, high job demands, remained related to lower odds of serious problems in one health domain among men, and low job control remained associated with higher odds of complex health problems among men. High job demands were associated with lower odds of complex health problems among men with low education, but not among men with high education, or among women regardless of level of education. The results underscore the importance of work-related stress for long-term health. Modification to work environment to reduce work stress (e.g., providing opportunities for self-direction/monitoring levels of psychological job demands) may serve as a springboard for the development of preventive strategies to improve public
Dealing with complex and ill-structured problems: results of a Plan-Do-Check-Act experiment in a business engineering semester

Science.gov (United States)

Riis, Jens Ove; Achenbach, Marlies; Israelsen, Poul; Kyvsgaard Hansen, Poul; Johansen, John; Deuse, Jochen

2017-07-01

Challenged by increased globalisation and fast technological development, we carried out an experiment in the third semester of a global business engineering programme aimed at identifying conditions for training student in dealing with complex and ill-structured problems of forming a new business. As this includes a fuzzy front end, learning cannot be measured in traditional, quantitative terms; therefore, we have explored the use of reflection to convert tacit knowledge to explicit knowledge. The experiment adopted a Plan-Do-Check-Act approach and concluded with developing a plan for new learning initiatives in the subsequent year's semester. The findings conclude that (1) problem-based learning develops more competencies than ordinarily measured at the examination, especially, the social/communication and personal competencies are developed; (2) students are capable of dealing with a complex and ambiguous problem, if properly guided. Four conditions were identified; (3) most students are not conscious of their learning, but are able to reflect if properly encouraged; and (4) improving engineering education should be considered as an organisational learning process.
Separated core turbofan engine; Core bunrigata turbofan engine

Energy Technology Data Exchange (ETDEWEB)

Saito, Y; Endo, M; Matsuda, Y; Sugiyama, N; Sugahara, N; Yamamoto, K [National Aerospace Laboratory, Tokyo (Japan)

1996-04-01

This report outlines the separated core turbofan engine. This engine is featured by parallel separated arrangement of a fan and core engine which are integrated into one unit in the conventional turbofan engine. In general, cruising efficiency improvement and noise reduction are achieved by low fan pressure ratio and low exhaust speed due to high bypass ratio, however, it causes various problems such as large fan and nacelle weight due to large air flow rate of a fan, and shift of an operating point affected by flight speed. The parallel separated arrangement is thus adopted. The stable operation of a fan and core engine is easily retained by independently operating air inlet unaffected by fan. The large degree of freedom of combustion control is also obtained by independent combustor. Fast response, simple structure and optimum aerodynamic design are easily achieved. This arrangement is also featured by flexibility of development and easy maintenance, and by various merits superior to conventional turbofan engines. It has no technological problems difficult to be overcome, and is also suitable for high-speed VTOL transport aircraft. 4 refs., 5 figs.
Children and Stress

OpenAIRE

Johansson, Camilla

2000-01-01

Abstract This paper is about children and stress. Stress among children is a serious problem and to be aware of that as a preschool teacher is very important. I’ve focused on the youngest children in preschool. I’ve searched for information in litterateur and articles. To fins literature is not a problem because it is a lot written about this subject. I did two interviews with three preschool teachers. All my sources agree that stress among children is a problem that we must try to work again...
Risk Analysis in Civil Engineering

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

Until fairly recently there has been a tendency for structural engineering to be dominated by deterministic thinking, characterised in design calculations by the use of specified minimum material properties, specified load intensities and by prescribed procedures for computing stresses and deflec......Until fairly recently there has been a tendency for structural engineering to be dominated by deterministic thinking, characterised in design calculations by the use of specified minimum material properties, specified load intensities and by prescribed procedures for computing stresses...
Lineage of global civil engineering. Global civil engineering no keifu

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, M

1994-04-15

This paper considers which way the global civil engineering should go in the future. Civil engineering has now a paradigm with a new dimension debuted as the global environmental problems are taken up specifically. Achieving the target of civil engineering requires a critical review that how the cost effect and efficiency discussions in only the dimensions of the conventional technologies and economies can be incorporated into the dimensions and measures of new fields to create the new horizons. Conceiving the relationship between civil engineered structures and environmental climate encounters the indispensable judgment criterion on how such social scientific conditions as weather, culture, religion, economy, and politics are combined to reach a judgment. The global civil engineering is desired to have the ideas and directional role to work on the ultimate assignment of environment and development called a global environmental problem analytically, comprehensively, innovatively and creatively as the civil engineering science, rather than as a mere existence of one area of the advanced civil engineering science. 5 refs., 1 tab.
Manipulating environmental stresses and stress tolerance of microalgae for enhanced production of lipids and value-added products-A review.

Science.gov (United States)

Chen, Bailing; Wan, Chun; Mehmood, Muhammad Aamer; Chang, Jo-Shu; Bai, Fengwu; Zhao, Xinqing

2017-11-01

Microalgae have promising potential to produce lipids and a variety of high-value chemicals. Suitable stress conditions such as nitrogen starvation and high salinity could stimulate synthesis and accumulation of lipids and high-value products by microalgae, therefore, various stress-modification strategies were developed to manipulate and optimize cultivation processes to enhance bioproduction efficiency. On the other hand, advancements in omics-based technologies have boosted the research to globally understand microalgal gene regulation under stress conditions, which enable further improvement of production efficiency via genetic engineering. Moreover, integration of multi-omics data, synthetic biology design, and genetic engineering manipulations exhibits a tremendous potential in the betterment of microalgal biorefinery. This review discusses the process manipulation strategies and omics studies on understanding the regulation of metabolite biosynthesis under various stressful conditions, and proposes genetic engineering of microalgae to improve bioproduction via manipulating stress tolerance. Copyright © 2017 Elsevier Ltd. All rights reserved.
Behavioral Problems and Emotional Difficulties at Children and Early Adolescents of the Veterans of War with Post-Traumatic Stress Disorder.

Science.gov (United States)

Selimbasic, Zihnet; Sinanovic, Osman; Avdibegovic, Esmina; Brkic, Maja; Hamidovic, Jasmin

2017-02-01

Behavioral problems and emotional difficulties at children of the veterans of war with post-traumatic stress disorder (PTSD) have not been researched entirely. In our country, which has a lot of persons suffering from some psychological traumas, this trauma seems to continue. The aim of this study was to determine the exposure, manifestations of behavioral problems and emotional difficulties at children and early adolescents, whose fathers were the veterans of war demonstrating post-traumatic stress disorder symptoms. The analyzed group comprised 120 school age children (10-15 years of age), whose parents/fathers were the veterans of war. The children were divided into two groups, and each group into the following two age sub-groups: 10-12 (children) and 13-15 (early adolescents) according to PTSD presence at their fathers - veterans of war. PTSD symptoms at fathers, veterans of war, were assessed using the Harvard Trauma Questionnaire-Bosnia and Herzegovina version and MKB-10 - audit of criteria. To assess the behavioral problems of children, the Child Behavior Checklist for parents was used, and to evaluate the neuroticism at children Hanes-Scale of neuroticism-extraversion was used while the depression level was evaluated using the Depression self-rating scale (DSRS). To analyze the obtained results, SPSS 17 program was used. The value p post-traumatic stress disorder show significant difference at neuroticism sub-scales (ppost-traumatic stress disorder show significant differences in competencies, behavior, emotional difficulties and neuroticism. Significant correlation was found between psychopathology of parents - fathers the veterans of war and their children. Impact of psychological conditions of fathers - the veterans of war with post-traumatic stress disorder to children is strong and they represent a significant risky group for development of mental disorders.
Combustion engineering

CERN Document Server

Ragland, Kenneth W

2011-01-01

Introduction to Combustion Engineering The Nature of Combustion Combustion Emissions Global Climate Change Sustainability World Energy Production Structure of the Book Section I: Basic Concepts Fuels Gaseous Fuels Liquid Fuels Solid Fuels Problems Thermodynamics of Combustion Review of First Law Concepts Properties of Mixtures Combustion StoichiometryChemical EnergyChemical EquilibriumAdiabatic Flame TemperatureChemical Kinetics of CombustionElementary ReactionsChain ReactionsGlobal ReactionsNitric Oxide KineticsReactions at a Solid SurfaceProblemsReferences Section II: Combustion of Gaseous and Vaporized FuelsFlamesLaminar Premixed FlamesLaminar Flame TheoryTurbulent Premixed FlamesExplosion LimitsDiffusion FlamesGas-Fired Furnaces and BoilersEnergy Balance and EfficiencyFuel SubstitutionResidential Gas BurnersIndustrial Gas BurnersUtility Gas BurnersLow Swirl Gas BurnersPremixed-Charge Engine CombustionIntroduction to the Spark Ignition EngineEngine EfficiencyOne-Zone Model of Combustion in a Piston-...
Fast assessment of the critical principal stress direction for multiple separated multiaxial loadings

Directory of Open Access Journals (Sweden)

M. Cova

2015-07-01

Full Text Available The critical plane calculation for multiaxial damage assessment is often a demanding task, particularly for large FEM models of real components. Anyway, in actual engineering requests, sometime, it is possible to take advantage of the specific properties of the investigated case. This paper deals with the problem of a mechanical component loaded by multiple, but “time-separated”, multiaxial external loads. The specific material damage is dependent from the max principal stress variation with a significant mean stress sensitivity too. A specifically fitted procedure was developed for a fast computation, at each node of a large FEM model, of the direction undergoing the maximum fatigue damage; the procedure is defined according to an effective stress definition based on the max principal stress amplitude and mean value. The procedure is presented in a general form, applicable to the similar cases.
Residual stress measurement in veneering ceramic by hole-drilling.

Science.gov (United States)

Mainjot, Amélie K; Schajer, Gary S; Vanheusden, Alain J; Sadoun, Michaël J

2011-05-01

Mismatch in thermal expansion properties between veneering ceramic and metallic or high-strength ceramic cores can induce residual stresses and initiate cracks when combined with functional stresses. Knowledge of the stress distribution within the veneering ceramic is a key factor for understanding and predicting chipping failures, which are well-known problems with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objectives of this study are to develop a method for measuring the stress profile in veneering ceramics and to compare ceramic-fused-to-metal compounds to veneered Yttria-tetragonal-zirconia-polycrystal ceramic. The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. Because of the high sensitivity needed in comparison with industrial applications, a high sensitivity electrical measurement chain was developed. All samples exhibited the same type of stress vs. depth profile, starting with compressive at the ceramic surface, decreasing with depth and becoming tensile at 0.5-1.0mm from the surface, and then becoming slightly compressive again. The zirconia samples exhibited a stress depth profile of larger magnitude. The hole drilling method was shown be a practical tool for measuring residual stresses in veneering ceramics. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Parental Stress, Discipline Strategies, and Child Behavior Problems in Families with Young Children with Autism Spectrum Disorders

Science.gov (United States)

Shawler, Paul M.; Sullivan, Maureen A.

2017-01-01

The current study investigated the parent-child relationship by examining associations between parent stress, parental discipline strategies, child disruptive behavior problems, and level of autism spectrum disorder (ASD) symptoms. A sample of 130 parents of children with ASD ages 3 to 11 years participated. Parents reported high levels of parent…

Neutrons and Nuclear Engineering

International Nuclear Information System (INIS)

Ekkebus, Allen E.

2007-01-01

Oak Ridge National Laboratory hosted two workshops in April 2007 relevant to nuclear engineering education. In the Neutron Stress, Texture, and Phase Transformation for Industry workshop (http://neutrons.ornl.gov/workshops/nst2/), several invited speakers gave examples of neutron stress mapping for nuclear engineering applications. These included John Root of National Research Council of Canada, Mike Fitzpatrick of the UK's Open University, and Yan Gao of GE Global Research on their experiences with industrial and academic uses of neutron diffraction. Xun-Li Wang and Camden Hubbard described the new instruments at ORNL that can be used for such studies. This was preceded by the Neutrons for Materials Science and Engineering educational symposium (http://neutrons.ornl.gov/workshops/edsym2007). It was directed to the broad materials science and engineering community based in universities, industry and laboratories who wish to learn what the neutron sources in the US can provide for enhancing the understanding of materials behavior, processing and joining. Of particular interest was the presentation of Donald Brown of Los Alamos about using 'Neutron diffraction measurements of strain and texture to study mechanical behavior of structural materials.' At both workshops, the ORNL neutron scattering instruments relevant to nuclear engineering studies were described. The Neutron Residual Stress Mapping Facility (NRSF2) is currently in operation at the High Flux Isotope Reactor; the VULCAN Engineering Materials Diffractometer will begin commissioning in 2008 at the Spallation Neutron Source. For characteristics of these instruments, as well as details of other workshops, meetings, capabilities, and research proposal submissions, please visit http://neutrons.ornl.gov. To submit user proposals for time on NRSF2 contact Hubbard at hubbardcratornl.gov
Proposal of thinking process model based on putting a question to oneself for problem solving by skilled engineers

International Nuclear Information System (INIS)

Fukumoto, Toshihiko; Kishi, Yoshiki

2007-01-01

The retirement of the skilled engineers and researchers, who have been working in the field of water chemistry of BWRs since the establishment of Japanese BWRs, has been accelerating so that it is necessary to preserve and share the knowledge and know-how of these skilled engineers and to effectively and securely inherit them to the following generations. Moreover, in order for other engineers to share knowledge, including the tacit knowledge of a skilled engineer, it is necessary not only to understand the knowledge obtained as the results of the thinking of the skilled engineers but also to externalize and experience their thinking processes as the processes of problem solving that produced the results. The target of this research is to build a new thinking process model that can externalize thinking processes effectively by analyzing the knowledge and thinking contents of the skilled engineers for investigating causes of changes in the quality of reactor water in boiling water reactor type power plants. As part of this research, we found out a new metacognitive activity, Putting a Question to Oneself, which plays a large role in the thinking process structure. In addition, we developed a new fundamental thinking process model, which can externalize thinking processes effectively by integrating the concept of Putting a Question to Oneself into the thinking process model. (author)
The earthquake problem in engineering design: generating earthquake design basis information

International Nuclear Information System (INIS)

Sharma, R.D.

1987-01-01

Designing earthquake resistant structures requires certain design inputs specific to the seismotectonic status of the region, in which a critical facility is to be located. Generating these inputs requires collection of earthquake related information using present day techniques in seismology and geology, and processing the collected information to integrate it to arrive at a consolidated picture of the seismotectonics of the region. The earthquake problem in engineering design has been outlined in the context of a seismic design of nuclear power plants vis a vis current state of the art techniques. The extent to which the accepted procedures of assessing seismic risk in the region and generating the design inputs have been adherred to determine to a great extent the safety of the structures against future earthquakes. The document is a step towards developing an aproach for generating these inputs, which form the earthquake design basis. (author)
Engineering Mathematics in Context

DEFF Research Database (Denmark)

Ravn, Ole; Henriksen, Lars Bo

2017-01-01

A theory-based approach to scientific research has an inherent tendency to become secluded from the ongoing problems and discussions of the surrounding society. A problem-based approach to research immediately involves this context of problems and discussions from the outset. In this article, we ...... argue that education in university engineering mathematics should take its outset in contextual problems in order to provide a foundation for the skills and capabilities engineers need in their future job settings, whether it be research or development activities....
Problems in differential equations

CERN Document Server

Brenner, J L

2013-01-01

More than 900 problems and answers explore applications of differential equations to vibrations, electrical engineering, mechanics, and physics. Problem types include both routine and nonroutine, and stars indicate advanced problems. 1963 edition.
Study of Scramjet Engine System

OpenAIRE

苅田, 丈士; KANDA, Takeshi

2001-01-01

1. Introduction The scramjet engine for the single-stage-to-orbit (SSTO) aerospace plane has been studied in the ramjet propulsion research division. The problems of the scramjet are (1) combustion, (2) light structure, (3) startability of the inlet, (4) integration of engines, and (5) cooling. The construction of the cooling system is important for the scramjet engine, because of high heat flux during operation. Cooling is not only a problem for the engine itself, but also for the airframe. ...
Rock stress measurements using the LUT-Gauge overcoring method

International Nuclear Information System (INIS)

Leijon, B.

1988-04-01

With overcoring techniques, rock stresses are determined indirectly from measurements of the dimensional changes of a borehole, occurring when the rock volume surrounding the hole is isolated from the stresses in the host rock. This thesis describes the development and application of an overcoring technique. The key-component of the instrumentation that has been developed is a triaxial borehole strain cell, referred to as the LUT-Gauge. Laboratory tests were conducted to evaluate the performance of the instrumentation. Special emphasis was given to determining temperature sensitivity of the measuring system since this was identified as a potential source of measurement error. Results indicated good instrument reliability and that the measurement error due to temperature variations typically experienced under field conditions is ± 1 MPa or less. The technique was also evaluated by a series of field tests. Comparison of the results obtained by the different methods showed satisfactory agreement. Analysis of the comprehensive field data collected showed that the confidence that can be attached to an overcoring test is largely governed by the mechanical characteristics of the overcored specimen. Expressed as the standard deviation of the mean stress magnitude, the scatter obtained from repeated testing within a borehole section of about 10 m in length, is found to be ± 4 MPa or less. Rock engineering investigations typically refer to a scale of hundreds of metres or more. This study has demonstrated the existence of significant variations of the stress field on this scale. These variations thus impose difficulties in the application of stress data to the analysis of problems in rock engineering, since the pointwise results obtained from stress measurements cannot be extrapolated with good confidence. (30 refs.) (author)
Child Behavior Checklist Juvenile Bipolar Disorder (CBCL-JBD) and CBCL Posttraumatic Stress Problems (CBCL-PTSP) Scales Are Measures of a Single Dysregulatory Syndrome

Science.gov (United States)

Ayer, Lynsay; Althoff, Robert; Ivanova, Masha; Rettew, David; Waxler, Ellen; Sulman, Julie; Hudziak, James

2009-01-01

Background: The Child Behavior Checklist Juvenile Bipolar Disorder (CBCL-JBD) profile and Posttraumatic Stress Problems (CBCL-PTSP) scale have been used to assess juvenile bipolar disorder (JBD) and posttraumatic stress disorder (PTSD), respectively. However, their validity is questionable according to previous research. Both measures are…
The Elaborated Environmental Stress Hypothesis as a Framework for Understanding the Association Between Motor Skills and Internalizing Problems: A Mini-Review

Science.gov (United States)

Mancini, Vincent O.; Rigoli, Daniela; Cairney, John; Roberts, Lynne D.; Piek, Jan P.

2016-01-01

Poor motor skills have been shown to be associated with a range of psychosocial issues, including internalizing problems (anxiety and depression). While well-documented empirically, our understanding of why this relationship occurs remains theoretically underdeveloped. The Elaborated Environmental Stress Hypothesis by Cairney et al. (2013) provides a promising framework that seeks to explain the association between motor skills and internalizing problems, specifically in children with developmental coordination disorder (DCD). The framework posits that poor motor skills predispose the development of internalizing problems via interactions with intermediary environmental stressors. At the time the model was proposed, limited direct evidence was available to support or refute the framework. Several studies and developments related to the framework have since been published. This mini-review seeks to provide an up-to-date overview of recent developments related to the Elaborated Environmental Stress Hypothesis. We briefly discuss the past research that led to its development, before moving to studies that have investigated the framework since it was proposed. While originally developed within the context of DCD in childhood, recent developments have found support for the model in community samples. Through the reviewed literature, this article provides support for the Elaborated Environmental Stress Hypothesis as a promising theoretical framework that explains the psychosocial correlates across the broader spectrum of motor ability. However, given its recent conceptualization, ongoing evaluation of the Elaborated Environmental Stress Hypothesis is recommended. PMID:26941690
Repetitive Stress Injuries

Science.gov (United States)

... Safe Videos for Educators Search English Español Repetitive Stress Injuries KidsHealth / For Teens / Repetitive Stress Injuries What's ... t had any problems since. What Are Repetitive Stress Injuries? Repetitive stress injuries (RSIs) are injuries that ...
Prevalence of stress, anxiety and depression in with Alzheimer caregivers

Directory of Open Access Journals (Sweden)

De Vito Elisabetta

2008-11-01

Full Text Available Abstract Background Alzheimer's disease presents a social and public health problem affecting millions of Italians. Those affected receive home care from caregivers, subjected to risk of stress. The present investigation focuses on stress, anxiety and depression in caregivers. Methods Data on 200 caregivers and their patients were collected using a specific form to assess cognitive, behavioural, functional patient (MMSE, and ADL-IAD and caregiver stress (CBI. The relationship between stress, depression and disease has been assessed by means of a linear regression, logistic analysis which reveals the relationship between anxiety, stress and depression and cognitive problems, age, the patient's income. Results The caregivers are usually female (64%, mean age of 56.1 years, daughters (70.5%, pensioners and housewives (30%, who care for the sick at home (79%. Of these, 53% had little time for themselves, 55% observed worsening of health, 56% are tired, 51% are not getting enough sleep. Overall, 55% have problems with the patient's family and/or their own family, 57% at work. Furthermore, 29% feel they are failing to cope with the situation as they wish to move away from home. The increase in the degree of anxiety and depression is directly proportional to the severity of the illness, affecting the patient (r = 0.3 stress and depression r = 0.4 related to CBI score. The memory disorders (OR = 8.4, engine problems (OR = 2.6, perception disorders (OR = 1.9 sick of the patient with Alzheimer's disease are predictive of caregiver stress, depression is associated with the presence of other disorders, mainly behavioural (OR = 5.2, low income (OR = 3.4, patients Conclusion The quality of life of caregivers is correlated with the severity of behavioural disorders and duration of the Alzheimer's disease. The severity of the disease plays an important role in reorganization of the family environment in families caring for patients not institutionalised. It is
Modified Backtracking Search Optimization Algorithm Inspired by Simulated Annealing for Constrained Engineering Optimization Problems

Directory of Open Access Journals (Sweden)

Hailong Wang

2018-01-01

Full Text Available The backtracking search optimization algorithm (BSA is a population-based evolutionary algorithm for numerical optimization problems. BSA has a powerful global exploration capacity while its local exploitation capability is relatively poor. This affects the convergence speed of the algorithm. In this paper, we propose a modified BSA inspired by simulated annealing (BSAISA to overcome the deficiency of BSA. In the BSAISA, the amplitude control factor (F is modified based on the Metropolis criterion in simulated annealing. The redesigned F could be adaptively decreased as the number of iterations increases and it does not introduce extra parameters. A self-adaptive ε-constrained method is used to handle the strict constraints. We compared the performance of the proposed BSAISA with BSA and other well-known algorithms when solving thirteen constrained benchmarks and five engineering design problems. The simulation results demonstrated that BSAISA is more effective than BSA and more competitive with other well-known algorithms in terms of convergence speed.
Two-phase screw-type engine - problems of the filling process; Zweiphasen-Schraubenmotor - Probleme des Fuellungsvorganges

Energy Technology Data Exchange (ETDEWEB)

Kauder, K.; Kliem, B. [Dortmund Univ. (Germany). FG Fluidenergiemaschinen

1998-12-31

The two-phase screw-type engine presents itself as a expansion engine in a trilateral-flash-cycle to use waste heat in the lower temperature range, because this displacement engine is able to expand working fluids with a high proportion of liquid. Due to the low critical velocity and the blocking flow, the two-phase flow in the inlet port of the screw-type engine has a great influence on the quality of energy transformation. A novel filling system with rotating short nozzles is presented. Less dissipation during the filling process is expected by this system, because the flash evaporation of the fluid will occur in the working chamber and not in the inlet port of the screw-type engine. (orig.) [Deutsch] Der Zweiphasen-Schraubenmotor besitzt als Expansionsmaschine in Trilateral-Flash-Cycle-Prozessen zur Nutzung von Abwaerme mit niedriger Temperatur deutliche Vorteile, da dieser Maschinentyp in der Lage ist, Arbeitsfluide mit einem hohen Fluessigkeitsanteil zu expandieren. Die Zweiphasenstroemung im Einlassbereich des Schraubenmotors hat aufgrund ihrer geringen kritischen Geschwindigkeit und der damit verbundenen blockierten Stroemung einen signifikanten Einfluss auf die Fuellung der Arbeitskammer und der Energiewandlungsguete des Motors. Ein hier vorgestelltes neuartiges Fuellungssystem mit rotierenden Kurzduesen laesst eine verbesserte Fuellung des Zweiphasen-Schraubenmotors erwarten, da es erst in den Arbeitskammern zur Flashverdampfung kommt. (orig.)
Problem Solution Processes of Musicians and Engineers: What do Their Approaches Look Like

Directory of Open Access Journals (Sweden)

Säde-Pirkko Nissilä

2015-06-01

Full Text Available PBL is learning through becoming conscious of practical and abstract problems and finding ways how to solve them. It can be a pattern which doesn’t follow traditional divisions of disciplines. In this article the material was collected from two, in the first sight, very different groups. One was music students (N = 62 who had to learn to solve various practical and theoretical problems in preparing a program for a series of concerts as collective and individual action. The method used was the 7-step method which divides learning into seven phases proceeding from creating the social frame of reference and mental models (steps 1–4 through actual work (steps 5–6 to the evaluation of the outcomes (step 7. Another group consisted of international, multicultural business leaders in engineering (N = 6. In using earlier the 7-step method, the approaches resembled those of the music students: deepening their professional competences. To engage their ability to use imagination and connect reality with brainstorming and mental flexibility, the creative PBL method 635 was used. Three practical problems were solved so that the solutions included new viewpoints which would be applied to meet the real needs in the near future. The results show that not only were the learning targets of both groups reached but, with reflection included, the processes widened the professional competences of the participants.
Engineering design: A cognitive process approach

Science.gov (United States)

Strimel, Greg Joseph

The intent of this dissertation was to identify the cognitive processes used by advanced pre-engineering students to solve complex engineering design problems. Students in technology and engineering education classrooms are often taught to use an ideal engineering design process that has been generated mostly by educators and curriculum developers. However, the review of literature showed that it is unclear as to how advanced pre-engineering students cognitively navigate solving a complex and multifaceted problem from beginning to end. Additionally, it was unclear how a student thinks and acts throughout their design process and how this affects the viability of their solution. Therefore, Research Objective 1 was to identify the fundamental cognitive processes students use to design, construct, and evaluate operational solutions to engineering design problems. Research Objective 2 was to determine identifiers within student cognitive processes for monitoring aptitude to successfully design, construct, and evaluate technological solutions. Lastly, Research Objective 3 was to create a conceptual technological and engineering problem-solving model integrating student cognitive processes for the improved development of problem-solving abilities. The methodology of this study included multiple forms of data collection. The participants were first given a survey to determine their prior experience with engineering and to provide a description of the subjects being studied. The participants were then presented an engineering design challenge to solve individually. While they completed the challenge, the participants verbalized their thoughts using an established "think aloud" method. These verbalizations were captured along with participant observational recordings using point-of-view camera technology. Additionally, the participant design journals, design artifacts, solution effectiveness data, and teacher evaluations were collected for analysis to help achieve the
Impact of an Engineering Case Study in a High School Pre-Engineering Course

Science.gov (United States)

Rutz, Eugene; Shafer, Michelle

2011-01-01

Students at an all-girls high school who were enrolled in an introduction to engineering course were presented an engineering case study to determine if the case study affected their attitudes toward engineering and their abilities to solve engineering problems. A case study on power plants was implemented during a unit on electrical engineering.…
The European Engineer: A British Civil Engineering Viewpoint.

Science.gov (United States)

Fleming, George

1988-01-01

Confronts the problems of defining the European Engineer in terms of educational and practical training. Analyzes the supply and demand requirements of engineering management and practice. Compares these analyses with conditions in the United States. Gives details of the educational process in a number of European countries. (CW)
Numerical methods and modelling for engineering

CERN Document Server

Khoury, Richard

2016-01-01

This textbook provides a step-by-step approach to numerical methods in engineering modelling. The authors provide a consistent treatment of the topic, from the ground up, to reinforce for students that numerical methods are a set of mathematical modelling tools which allow engineers to represent real-world systems and compute features of these systems with a predictable error rate. Each method presented addresses a specific type of problem, namely root-finding, optimization, integral, derivative, initial value problem, or boundary value problem, and each one encompasses a set of algorithms to solve the problem given some information and to a known error bound. The authors demonstrate that after developing a proper model and understanding of the engineering situation they are working on, engineers can break down a model into a set of specific mathematical problems, and then implement the appropriate numerical methods to solve these problems. Uses a “building-block” approach, starting with simpler mathemati...
Engineering management of large scale systems

Science.gov (United States)

Sanders, Serita; Gill, Tepper L.; Paul, Arthur S.

1989-01-01

The organization of high technology and engineering problem solving, has given rise to an emerging concept. Reasoning principles for integrating traditional engineering problem solving with system theory, management sciences, behavioral decision theory, and planning and design approaches can be incorporated into a methodological approach to solving problems with a long range perspective. Long range planning has a great potential to improve productivity by using a systematic and organized approach. Thus, efficiency and cost effectiveness are the driving forces in promoting the organization of engineering problems. Aspects of systems engineering that provide an understanding of management of large scale systems are broadly covered here. Due to the focus and application of research, other significant factors (e.g., human behavior, decision making, etc.) are not emphasized but are considered.
Perceived child behaviour problems, parenting stress, and marital satisfaction: comparison of new arrival and local parents of preschool children in Hong Kong.

Science.gov (United States)

Leung, Shirley S L; Leung, Cynthia; Chan, Ruth

2007-10-01

To compare parental perception of child behaviour problems, parenting stress, and marital satisfaction in new arrival and local parents. Cross-sectional survey; semi-structured interview. Maternal and Child Health Centres, social service centres, preschools. Parents of preschool children, including new arrival parents and local parents. Child behaviour problems, parenting stress, and marital satisfaction. After controlling for socio-economic factors, new arrival parents were more troubled by their children's behaviour problems and their parent-child interactions were more dysfunctional than those of local parents. There were no differences in parent-reported severity of child behaviour problems, parental distress, and marital satisfaction. New arrival parents reported difficulties in adapting to the new living environment and lack of social support. New arrival parents were more troubled by their children's behaviour, and their parent-child interactions were more dysfunctional than those of local parents. These might in part be related to their settlement difficulties. Parenting programmes should address their specific settlement needs.

Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

Science.gov (United States)

Li, Jianwei; Zhang, Weimin; Zeng, Weiqin; Chen, Guolong; Qiu, Zhongchao; Cao, Xinyuan; Gao, Xuanyi

2017-01-01

Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235) specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.
Genetic Engineering

Science.gov (United States)

Phillips, John

1973-01-01

Presents a review of genetic engineering, in which the genotypes of plants and animals (including human genotypes) may be manipulated for the benefit of the human species. Discusses associated problems and solutions and provides an extensive bibliography of literature relating to genetic engineering. (JR)
Interactive simulations as teaching tools for engineering mechanics courses

International Nuclear Information System (INIS)

Carbonell, Victoria; Martínez, Elvira; Flórez, Mercedes; Romero, Carlos

2013-01-01

This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills. (paper)
The Impact of Problem-Based Learning on Engineering Students' Beliefs about Physics and Conceptual Understanding of Energy and Momentum

Science.gov (United States)

Sahin, Mehmet

2010-01-01

The purpose of this paper is to investigate the impact of problem-based learning (PBL) on freshmen engineering students' beliefs about physics and physics learning (referred to as epistemological beliefs) and conceptual understanding of physics. The multiple-choice test of energy and momentum concepts and the Colorado learning attitudes about…
The effect of Problem/Project-Based Learning on a desired skill set for construction professionals

Science.gov (United States)

Sirotiak, Todd L.

The purpose of this study was to investigate if a Problem/Project-Based Learning (PBL) approach can affect certain non-technical, "soft" skills of construction engineers. Such skills include leadership, adaptability, and stress management. In mixed design research, quantitative and qualitative data are assembled and analyzed collectively. For this study, two separate assessment tools were used for the quantitative portion, while open-ended written reflections and a partially closed-ended senior questionnaire were implemented for the qualitative portion. A hypothetical model was used to investigate certain soft skills based on prior research documenting need. Skills investigated were confidence, stress coping, leadership, communication skills, adaptability, and management skills. Descriptive statistics, open-ended final written reflections, and a partially closed-ended senior questionnaire were used to analyze the data. PBL is a process in which the students are challenged to develop realistic solutions on open, less structured, real world type problems. The results of this study performed with the combined count of nearly 60 students suggest that PBL can influence several soft skills of senior construction engineers. Specifically, these findings demonstrate the following: (a) PBL appears to affect students' soft skills; (b) students appear to recognize the realism and "real world" applicability that PBL brings to their skill development; and (c) the data suggest that the experience is holistic and offers opportunities for balanced growth in several ways. Some key competencies such as communication and leadership indicated significant enhancements. Although this study was limited to one academic year of the university's construction engineering program, it provides interesting insight to changes within the time period investigated. This study should be replicated in other construction engineering environments to investigate a larger population sample. In addition
High voltage engineering

CERN Document Server

Rizk, Farouk AM

2014-01-01

Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec
Work stress, worries, and pain interact synergistically with modelled traffic noise on cross-sectional associations with self-reported sleep problems.

Science.gov (United States)

Kristiansen, Jesper; Persson, Roger; Björk, Jonas; Albin, Maria; Jakobsson, Kristina; Ostergren, Per-Olof; Ardö, Jonas

2011-02-01

To examine the risk of sleep problems associated with work stress (job strain, job demands, and decision authority), worries and pain and to investigate the synergistic interaction between these factors and traffic noise. Sleep problems and predictor variables were assessed in a cross-sectional public health survey with 12,093 respondents. Traffic noise levels were assessed using modelled A-weighted energy equivalent traffic sound levels at the residence. The risk of sleep problems was modelled using multiple logistic regression analysis. With regard to sleep problems not attributed to any external source (general sleep problems), independent main effects were found for traffic noise (women), decision authority (women), job strain, job demands, suffering from pain or other afflictions, worries about losing the job, experiencing bullying at work, having troubles paying the bills, and having a sick, disabled, or old relative to take care of (women). Significant synergistic effects were found for traffic noise and experiencing bullying at work in women. With regard to sleep problems attributed to traffic noise, strong synergistic interactions were found between traffic noise and, respectively, job demands (men), having pain or other afflictions, taking care of a sick, old, or disabled relative, and having troubles paying the bills. Main effects were found for worries about losing the job, experiencing bullying at work, job strain (men), and decision authority (men). Synergistic interactions could potentially contribute with 10-20% of the sleep problems attributed to traffic noise in the population. Work stress, pain, and different worries were independently associated with general sleep problems and showed in general no synergistic interaction with traffic noise. In contrast, synergistic effects between traffic noise and psychological factors were found with regard to sleep problems attributed to traffic noise. The synergy may contribute significantly to sleep
Communication and coping as predictors of fertility problem stress: cohort study of 816 participants who did not achieve a delivery after 12 months of fertility treatment

DEFF Research Database (Denmark)

Schmidt, L; Holstein, B E; Christensen, Ulla

2005-01-01

BACKGROUND: We investigated coping strategies and communication strategies as predictors of fertility problem stress 12 months after start of fertility treatment. METHODS: We used a prospective, longitudinal cohort design including 2250 people beginning fertility treatment with a 12-month follow......-up. Data were based on self-administered questionnaires measuring communication with partner and with other people, coping strategies: active-avoidance coping, active-confronting coping, passive-avoidance coping, meaning-based coping, and fertility problem stress. The study population included those...... participants (n = 816, men and women) who had not achieved pregnancy by assisted reproduction or delivery at follow-up. RESULTS: Among both men and women, difficulties in partner communication predicted high fertility problem stress (odds ratio for women, 3.47, 95% confidence interval 2.09-5.76; odds ratio...
Semantic Oriented Agent based Approach towards Engineering Data Management, Web Information Retrieval and User System Communication Problems

OpenAIRE

Ahmed, Zeeshan; Gerhard, Detlef

2010-01-01

The four intensive problems to the software rose by the software industry .i.e., User System Communication / Human Machine Interface, Meta Data extraction, Information processing & management and Data representation are discussed in this research paper. To contribute in the field we have proposed and described an intelligent semantic oriented agent based search engine including the concepts of intelligent graphical user interface, natural language based information processing, data management...
Axi-symmetric generalized thermoelastic diffusion problem with two-temperature and initial stress under fractional order heat conduction

International Nuclear Information System (INIS)

Deswal, Sunita; Kalkal, Kapil Kumar; Sheoran, Sandeep Singh

2016-01-01

A mathematical model of fractional order two-temperature generalized thermoelasticity with diffusion and initial stress is proposed to analyze the transient wave phenomenon in an infinite thermoelastic half-space. The governing equations are derived in cylindrical coordinates for a two dimensional axi-symmetric problem. The analytical solution is procured by employing the Laplace and Hankel transforms for time and space variables respectively. The solutions are investigated in detail for a time dependent heat source. By using numerical inversion method of integral transforms, we obtain the solutions for displacement, stress, temperature and diffusion fields in physical domain. Computations are carried out for copper material and displayed graphically. The effect of fractional order parameter, two-temperature parameter, diffusion, initial stress and time on the different thermoelastic and diffusion fields is analyzed on the basis of analytical and numerical results. Some special cases have also been deduced from the present investigation.
NDE in biomedical engineering

International Nuclear Information System (INIS)

Bhagwat, Aditya; Kumar, Pradeep

2015-01-01

Biomedical Engineering (BME) is an interdisciplinary field, marking the conjunction of Medical and Engineering disciplines. It combines the design and problem solving skills of engineering with medical and biological sciences to advance health care treatment, including diagnosis, monitoring, and therapy
Stress revisited: A critical evaluation of the stress concept

NARCIS (Netherlands)

Koolhaas, J.M.; Bartolomucci, A.; Buwalda, B.; de Boer, S.F.; Flügge, G.; Korte, S.M.; Meerloo, P.; Murison, R.; Olivier, B.; Palanza, P.; Richter-Levin, G.; Sgoifo, A.; Steimer, T.; Stiedl, O.; van Dijk, G.; Wöhr, M.; Fuchs, E.

2011-01-01

With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely
Stress revisited : a critical evaluation of the stress concept

NARCIS (Netherlands)

Koolhaas, J.M.; Bartolomucci, A; Buwalda, B; Flügge, G; de Boer, Sietse; Korte, S M; Meerlo, P; Murison, R; Olivier, B; Palanza, P; Richter-Levin, G; Sgoifo, A; Steimer, T; Stiedl, O; van Dijk, G; Wöhr, M; Fuchs, E

2011-01-01

With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely
Neutron and ultrasonic determination of residual stress in an aluminum ring-plug

International Nuclear Information System (INIS)

Prask, H.J.; Gnaeupel-Herold, T.; Clark, A.V.; Hehman, C.S.; Nguyen, T.N.

2000-01-01

Stress is a principal cause of material failure. This has been a well-recognized problem for decades, yet--in general--neutron diffraction remains the only way to measure sub-surface residual stresses without destroying the component. A field-portable ultrasonic strain-meter is being developed at NIST (Boulder) to determine residual stresses in engineering specimens, nondestructively. To test this and other techniques an array of stress-measurement standards are being prepared. These will be characterized by neutron diffraction and then used to evaluate, quantitatively, the potential of new methods. The first standard specimen produced for this purpose is a large shrink-fit ring-plug of 2024 aluminum (305 mm OD, 25.4 mm thick, 101.6 mm diameter plug). Because of large grain size, a sample-rotation averaging technique was developed to make reliable neutron measurements possible. A comparison of the neutron diffraction and ultrasonic results for this specimen will be presented, along with strain gauge results
Association of work-related stress with mental health problems in a special police force unit.

Science.gov (United States)

Garbarino, Sergio; Cuomo, Giovanni; Chiorri, Carlo; Magnavita, Nicola

2013-01-01

Law and order enforcement tasks may expose special force police officers to significant psychosocial risk factors. The aim of this work is to investigate the relationship between job stress and the presence of mental health symptoms while controlling sociodemographical, occupational and personality variables in special force police officers. At different time points, 292 of 294 members of the 'VI Reparto Mobile', a special police force engaged exclusively in the enforcement of law and order, responded to our invitation to complete questionnaires for the assessment of personality traits, work-related stress (using the Demand-Control-Support (DCS) and the Effort-Reward-Imbalance (ERI) models) and mental health problems such as depression, anxiety and burnout. Regression analyses showed that lower levels of support and reward and higher levels of effort and overcommitment were associated with higher levels of mental health symptoms. Psychological screening revealed 21 (7.3%) likely cases of mild depression (Beck Depression Inventory, BDI≥10). Officers who had experienced a discrepancy between work effort and rewards showed a marked increase in the risk of depression (OR 7.89, 95% CI 2.32 to 26.82) when compared with their counterparts who did not perceive themselves to be in a condition of distress. The findings of this study suggest that work-related stress may play a role in the development of mental health problems in police officers. The prevalence of mental health symptoms in the cohort investigated here was low, but not negligible in the case of depression. Since special forces police officers have to perform sensitive tasks for which a healthy psychological functioning is needed, the results of this study suggest that steps should be taken to prevent distress and improve the mental well-being of these workers.
Development of stress corrosion cracking resistant welds of 321 stainless steel by simple surface engineering

Science.gov (United States)

Mankari, Kamal; Acharyya, Swati Ghosh

2017-12-01

We hereby report a simple surface engineering technique to make AISI grade 321 stainless steel (SS) welds resistant to stress corrosion cracking (SCC) in chloride environment. Heat exchanger tubes of AISI 321 SS, welded either by (a) laser beam welding (LBW) or by (b) metal inert gas welding (MIG) were used for the study. The welds had high magnitude of tensile residual stresses and had undergone SCC in chloride environment while in service. The welds were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Subsequently, the welded surfaces were subjected to buffing operation followed by determination of residual stress distribution and surface roughness by XRD and surface profilometer measurements respectively. The susceptibility of the welds to SCC was tested in buffed and un-buffed condition as per ASTM G-36 in boiling MgCl2 for 5 h and 10 h, followed by microstructural characterization by using optical microscope and FESEM. The results showed that the buffed surfaces (both welds and base material) were resistant to SCC even after 10 h of exposure to boiling MgCl2 whereas the un-buffed surfaces underwent severe SCC for the same exposure time. Buffing imparted high magnitude of compressive stresses on the surface of stainless steel together with reduction in its surface roughness and reduction in plastic strain on the surface which made the welded surface, resistant to chloride assisted SCC. Buffing being a very simple, portable and economic technique can be easily adapted by the designers as the last step of component fabrication to make 321 stainless steel welds resistant to chloride assisted SCC.
Engineering Mathematics I : Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering

CERN Document Server

Rančić, Milica

2016-01-01

This book highlights the latest advances in engineering mathematics with a main focus on the mathematical models, structures, concepts, problems and computational methods and algorithms most relevant for applications in modern technologies and engineering. In particular, it features mathematical methods and models of applied analysis, probability theory, differential equations, tensor analysis and computational modelling used in applications to important problems concerning electromagnetics, antenna technologies, fluid dynamics, material and continuum physics and financial engineering. The individual chapters cover both theory and applications, and include a wealth of figures, schemes, algorithms, tables and results of data analysis and simulation. Presenting new methods and results, reviews of cutting-edge research, and open problems for future research, they equip readers to develop new mathematical methods and concepts of their own, and to further compare and analyse the methods and results discussed. The ...
The Elaborated Environmental Stress Hypothesis as a Framework for Understanding the Association between Motor Skills and Internalizing Problems: A mini-review

Directory of Open Access Journals (Sweden)

Vincent Oreste Mancini

2016-02-01

Full Text Available Poor motor skills have been shown to be associated with a range of psychosocial issues, including internalizing problems (anxiety and depression. While well-documented empirically, our understanding of why this relationship occurs remains theoretically underdeveloped. The Elaborated Environmental Stress Hypothesis by Cairney, Rigoli, and Piek (2013 provides a promising framework that seeks to explain the association between motor skills and internalizing problems, specifically in children with Developmental Coordination Disorder (DCD. The framework posits that poor motor skills predispose the development of internalizing problems via interactions with intermediary environmental stressors. At the time the model was proposed, limited direct evidence was available to support or refute the framework. Several studies and developments related to the framework have since been published. This mini-review seeks to provide an up-to-date overview of recent developments related to the Elaborated Environmental Stress Hypothesis. We briefly discuss the past research that led to its development, before moving to studies that have investigated the framework since it was proposed. While originally developed within the context of DCD in childhood, recent developments have found support for the model in community samples. Through the reviewed literature, this article provides support for the Elaborated Environmental Stress Hypothesis as a promising theoretical framework that explains the psychosocial correlates across the broader spectrum of motor ability. This evidence promotes the external validity of the framework for use across the broader spectrum of motor ability. However, given its recent conceptualisation, ongoing evaluation of the Elaborated Environmental Stress Hypothesis is recommended.
Educating the humanitarian engineer.

Science.gov (United States)

Passino, Kevin M

2009-12-01

The creation of new technologies that serve humanity holds the potential to help end global poverty. Unfortunately, relatively little is done in engineering education to support engineers' humanitarian efforts. Here, various strategies are introduced to augment the teaching of engineering ethics with the goal of encouraging engineers to serve as effective volunteers for community service. First, codes of ethics, moral frameworks, and comparative analysis of professional service standards lay the foundation for expectations for voluntary service in the engineering profession. Second, standard coverage of global issues in engineering ethics educates humanitarian engineers about aspects of the community that influence technical design constraints encountered in practice. Sample assignments on volunteerism are provided, including a prototypical design problem that integrates community constraints into a technical design problem in a novel way. Third, it is shown how extracurricular engineering organizations can provide a theory-practice approach to education in volunteerism. Sample completed projects are described for both undergraduates and graduate students. The student organization approach is contrasted with the service-learning approach. Finally, long-term goals for establishing better infrastructure are identified for educating the humanitarian engineer in the university, and supporting life-long activities of humanitarian engineers.
Engineering Bereitschaft as an enabler for Concurrent Engineering

DEFF Research Database (Denmark)

Christiansen, Kåre; Vesterager, Johan

1999-01-01

Industrial companies observe a general trend towards more customised products and shorter product life cycles. Furthermore, the market demands shorter lead-time and high-quality products at a competitive price. Concurrent Engineering address these challenges. Product modelling is a key aspect...... of the Concurrent Engineering literature. One problem with the product modelling literature is that it tends to assume that product development is revolutionary. Very often product development is evolutionary and it means that product modelling should have a major emphasis on reuse. In this paper it is suggested...... that industrial companies should develop an engineering development Bereitschaft (preparatory engineering knowledge) as an approach to Concurrent Engineering and product modelling. To develop such an engineering development Bereitschaft, a company must develop company generic product models.This paper...

Biopolitics problems of large-scale hydraulic engineering construction

International Nuclear Information System (INIS)

Romanenko, V.D.

1997-01-01

The XX century which will enter in a history as a century of large-scale hydraulic engineering constructions come to the finish. Only on the European continent 517 large reservoirs (more than 1000 million km 3 of water were detained, had been constructed for a period from 1901 till 1985. In the Danube basin a plenty for reservoirs of power stations, navigations, navigating sluices and other hydraulic engineering structures are constructed. Among them more than 40 especially large objects are located along the main bed of the river. A number of hydro-complexes such as Dnieper-Danube and Gabcikovo, Danube-Oder-Labe (project), Danube-Tissa, Danube-Adriatic Sea (project), Danube-Aegean Sea, Danube-Black Sea ones, are entered into operation or are in a stage of designing. Hydraulic engineering construction was especially heavily conducted in Ukraine. On its territory some large reservoirs on Dnieper and Yuzhny Bug were constructed, which have heavily changed the hydrological regime of the rivers. Summarised the results of river systems regulating in Ukraine one can be noted that more than 27 thousand ponds (3 km 3 per year), 1098 reservoirs of total volume 55 km 3 , 11 large channels of total length more than 2000 km and with productivity of 1000 m 2 /s have been created in Ukraine. Hydraulic engineering construction played an important role in development of the industry and agriculture, water-supply of the cities and settlements, in environmental effects, and maintenance of safe navigation in Danube, Dnieper and other rivers. In next part of the paper, the environmental changes after construction of the Karakum Channel on the Aral Sea in the Middle Asia are discussed
Teaching and Learning in Chemical Product Engineering - an Evolving par of the Chemical Engineering Curriculum

DEFF Research Database (Denmark)

Vigild, Martin Etchells; Kiil, Søren; Wesselingh, Johannes

2007-01-01

Over the last decade Chemical Product Engineering has evolved as part of the Chemical Engineering Curriculum at several universities in Europe and America. At the DTU Chemical Product Engineering was introduced in 2000. This presentation will report on the experiences gained from teaching classes...... and preparing a text book on the subject. [1] Chemical Product Engineering is solidly based on chemical technical and engineering knowledge. Furthermore, the subject naturally calls for a holistic approach to teaching and learning and introduces elements which target transferable and professional engineering...... skills. Such skills are important in Chemical Product Engineering when dealing with open-ended problems, creative problem solutions, operating in a team working environment and exercising project management. In our course we emphasise team activites, formative feed back to the students as well as helping...
Test of the role of nicotine dependence in the relation between posttraumatic stress disorder and panic spectrum problems.

Science.gov (United States)

Feldner, Matthew T; Smith, Rose C; Babson, Kimberly A; Sachs-Ericsson, Natalie; Schmidt, Norman B; Zvolensky, Michael J

2009-02-01

Posttraumatic stress disorder (PTSD) frequently co-occurs with panic spectrum problems. Relatively little empirical work has tested possible mechanisms accounting for this association. Nicotine dependence often ensues subsequent to PTSD onset and research suggests smoking high numbers of cigarettes daily may lead to panic problems. The current study tested the hypotheses that nicotine dependence partially mediates the relations between PTSD and both panic attacks and panic disorder within a nationally representative sample of 5,692 (3,020 women; M(Age) = 45, SD = 18) adults from the National Comorbidity Survey-Replication. Results were consistent with hypotheses. These findings support the theory suggesting smoking among people with PTSD may be involved in the development of panic problems.
Main results of BN-600 reactor stress-strain state investigations

International Nuclear Information System (INIS)

Panov, V.A.

1983-01-01

The development of BN-600 fast reactor plant needed the solution of a series of complex engineering problems including ones for confirming integrity of the most vital structural components. The particular attention was given to the main vessel since reactor availability end safe operation of the plant as a whole depend on vessel strength end integrity. The present report deals with the main results of theoretical and experimental investigations of the stress-strain state of BN-600 reactor vessel carried out during design, start-up and initial bringing the reactor to power
Designing requirements engineering research

NARCIS (Netherlands)

Wieringa, Roelf J.; Heerkens, Johannes M.G.

2007-01-01

Engineering sciences study different topics than natural sciences, and utility is an essential factor in choosing engineering research problems. But despite these differences, research methods for the engineering sciences are no different than research methods for any other kind of science. At most
Introduction to biomedical engineering

CERN Document Server

Enderle, John D; Blanchard, Susan M

2005-01-01

Under the direction of John Enderle, Susan Blanchard and Joe Bronzino, leaders in the field have contributed chapters on the most relevant subjects for biomedical engineering students. These chapters coincide with courses offered in all biomedical engineering programs so that it can be used at different levels for a variety of courses of this evolving field. Introduction to Biomedical Engineering, Second Edition provides a historical perspective of the major developments in the biomedical field. Also contained within are the fundamental principles underlying biomedical engineering design, analysis, and modeling procedures. The numerous examples, drill problems and exercises are used to reinforce concepts and develop problem-solving skills making this book an invaluable tool for all biomedical students and engineers. New to this edition: Computational Biology, Medical Imaging, Genomics and Bioinformatics. * 60% update from first edition to reflect the developing field of biomedical engineering * New chapters o...
Groundwater development stress: Global-scale indices compared to regional modeling

Science.gov (United States)

Alley, William; Clark, Brian R.; Ely, Matt; Faunt, Claudia

2018-01-01

The increased availability of global datasets and technologies such as global hydrologic models and the Gravity Recovery and Climate Experiment (GRACE) satellites have resulted in a growing number of global-scale assessments of water availability using simple indices of water stress. Developed initially for surface water, such indices are increasingly used to evaluate global groundwater resources. We compare indices of groundwater development stress for three major agricultural areas of the United States to information available from regional water budgets developed from detailed groundwater modeling. These comparisons illustrate the potential value of regional-scale analyses to supplement global hydrological models and GRACE analyses of groundwater depletion. Regional-scale analyses allow assessments of water stress that better account for scale effects, the dynamics of groundwater flow systems, the complexities of irrigated agricultural systems, and the laws, regulations, engineering, and socioeconomic factors that govern groundwater use. Strategic use of regional-scale models with global-scale analyses would greatly enhance knowledge of the global groundwater depletion problem.
On a Minimum Problem in Smectic Elastomers

International Nuclear Information System (INIS)

Buonsanti, Michele; Giovine, Pasquale

2008-01-01

Smectic elastomers are layered materials exhibiting a solid-like elastic response along the layer normal and a rubbery one in the plane. Balance equations for smectic elastomers are derived from the general theory of continua with constrained microstructure. In this work we investigate a very simple minimum problem based on multi-well potentials where the microstructure is taken into account. The set of polymeric strains minimizing the elastic energy contains a one-parameter family of simple strain associated with a micro-variation of the degree of freedom. We develop the energy functional through two terms, the first one nematic and the second one considering the tilting phenomenon; after, by developing in the rubber elasticity framework, we minimize over the tilt rotation angle and extract the engineering stress
The Role of Parenting Stress in Discrepancies between Parent and Teacher Ratings of Behavior Problems in Young Children with Autism Spectrum Disorder

Science.gov (United States)

Reed, Phil; Osborne, Lisa A.

2013-01-01

The study assessed whether teacher and parent ratings of child behavior problems were similar for children with autism spectrum disorders. Two informants rated child behaviors in the same home environment, and the degree to which parenting stress impacted the similarity of the ratings was assessed. Overall behavior problem ratings did not differ…
Association of Stressful Life Events with Psychological Problems: A Large-Scale Community-Based Study Using Grouped Outcomes Latent Factor Regression with Latent Predictors

Directory of Open Access Journals (Sweden)

Akbar Hassanzadeh

2017-01-01

Full Text Available Objective. The current study is aimed at investigating the association between stressful life events and psychological problems in a large sample of Iranian adults. Method. In a cross-sectional large-scale community-based study, 4763 Iranian adults, living in Isfahan, Iran, were investigated. Grouped outcomes latent factor regression on latent predictors was used for modeling the association of psychological problems (depression, anxiety, and psychological distress, measured by Hospital Anxiety and Depression Scale (HADS and General Health Questionnaire (GHQ-12, as the grouped outcomes, and stressful life events, measured by a self-administered stressful life events (SLEs questionnaire, as the latent predictors. Results. The results showed that the personal stressors domain has significant positive association with psychological distress (β=0.19, anxiety (β=0.25, depression (β=0.15, and their collective profile score (β=0.20, with greater associations in females (β=0.28 than in males (β=0.13 (all P<0.001. In addition, in the adjusted models, the regression coefficients for the association of social stressors domain and psychological problems profile score were 0.37, 0.35, and 0.46 in total sample, males, and females, respectively (P<0.001. Conclusion. Results of our study indicated that different stressors, particularly those socioeconomic related, have an effective impact on psychological problems. It is important to consider the social and cultural background of a population for managing the stressors as an effective approach for preventing and reducing the destructive burden of psychological problems.
Association of Stressful Life Events with Psychological Problems: A Large-Scale Community-Based Study Using Grouped Outcomes Latent Factor Regression with Latent Predictors

Science.gov (United States)

Hassanzadeh, Akbar; Heidari, Zahra; Hassanzadeh Keshteli, Ammar; Afshar, Hamid

2017-01-01

Objective The current study is aimed at investigating the association between stressful life events and psychological problems in a large sample of Iranian adults. Method In a cross-sectional large-scale community-based study, 4763 Iranian adults, living in Isfahan, Iran, were investigated. Grouped outcomes latent factor regression on latent predictors was used for modeling the association of psychological problems (depression, anxiety, and psychological distress), measured by Hospital Anxiety and Depression Scale (HADS) and General Health Questionnaire (GHQ-12), as the grouped outcomes, and stressful life events, measured by a self-administered stressful life events (SLEs) questionnaire, as the latent predictors. Results The results showed that the personal stressors domain has significant positive association with psychological distress (β = 0.19), anxiety (β = 0.25), depression (β = 0.15), and their collective profile score (β = 0.20), with greater associations in females (β = 0.28) than in males (β = 0.13) (all P < 0.001). In addition, in the adjusted models, the regression coefficients for the association of social stressors domain and psychological problems profile score were 0.37, 0.35, and 0.46 in total sample, males, and females, respectively (P < 0.001). Conclusion Results of our study indicated that different stressors, particularly those socioeconomic related, have an effective impact on psychological problems. It is important to consider the social and cultural background of a population for managing the stressors as an effective approach for preventing and reducing the destructive burden of psychological problems. PMID:29312459
Diesel Engine Convert to Port Injection CNG Engine Using Gaseous Injector Nozzle Multi Holes Geometries Improvement: A Review

OpenAIRE

Semin; Abdul R. Ismail; Rosli A. Bakar

2009-01-01

The objective of this study was to review the previous research in the development of gaseous fuel injector for port injection CNG engine converted from diesel engine. Problem statement: The regular development of internal combustion engines change direction to answer the two most important problems determining the development trends of engines technology and in particular, their combustion systems. They were environmental protection against emission and noise, shortage of hydrocarbon fuels, ...
How to solve mathematical problems

CERN Document Server

Wickelgren, Wayne A

1995-01-01

Seven problem-solving techniques include inference, classification of action sequences, subgoals, contradiction, working backward, relations between problems, and mathematical representation. Also, problems from mathematics, science, and engineering with complete solutions.
Engineering Sustainable Solutions Program: Critical Literacies for Engineers Portfolio

Science.gov (United States)

Paten, Cheryl J. K.; Palousis, Nicholas; Hargroves, Karlson; Smith, Michael

2005-01-01

Purpose: While a number of universities in Australia have embraced concepts such as project/problem-based learning and design of innovative learning environments for engineering education, there has been a lack of national guidance on including sustainability as a "critical literacy" into all engineering streams. This paper was presented…
Thermal shock problems in a plate

International Nuclear Information System (INIS)

Takeuti, Y.; Furukawa, T.

1981-01-01

The problems considered are coupled dynamic thermoelastic analysis in a plate. First we try to examine a problem of the coupled dynamic thermal stress problem with small time approximation for the finite region. Next, we treatise both effects individually by pursuing rigorous anaylsis without small time approximation. Finally we consider thermal shock problems in a plate against different values of heat transfer coefficient (Biot's number) for the time. In conclusion, for usual materials, the inertia effect may be disregarded in the pure thermal problems in contrast to the coupling effect which brings small lags in the temperature and thermal stress distributions. For the consideration of the maximum thermal stress problems, Manson's uncoupled quasi-static results give enough approximation to the thermal shock problems without significant error from our numerical results. The analysis is developed by the use of Laplace transforms and several useful graphical illustrations are given. (orig./HP)
Engineering Task Plan for Routine Engineering Support for Core Sampler System

International Nuclear Information System (INIS)

BOGER, R.M.

1999-01-01

Routine engineering support is required during normal operation of the core sampler trucks and associated ancillary equipment. This engineering support consists of, but is not limited to, troubleshooting operation problems, correcting minor design problems, assistance with work package preparation, assistance with procurement, fabrication shop support, planning of engineering tasks and preparation of associated Engineering Task Plans (ETP) and Engineering Service Requests (ESR). This ETP is the management plan document for implementing routine engineering support. Any additional changes to the scope of this ETP shall require a Letter of Instruction from Lockheed Martin Hanford Corp (LMHC). This document will also be the Work Planning Document for Development Control (HNF 1999a). The scope of this task will be to provide routine engineering support for Characterization equipment as required to support Characterization Operations. A task by task decision will be made by management to determine which tasks will be done per this ETP and if additional ETPs and/or ESRs are required. Due to the unique nature of this task, the only identifiable deliverable is to provide support as requested. Deliverables will be recorded in a task logbook as activities are identified. ESRs will be generated for tasks that require more than 40 person hours to complete, per Characterization Engineering Desk Instructions (DI 1999a)
Effect of Diesel Engine Converted to Sequential Port Injection Compressed Natural Gas Engine on the Cylinder Pressure vs Crank Angle in Variation Engine Speeds

OpenAIRE

Semin; Abdul R. Ismail; Rosli A. Bakar

2009-01-01

The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is b...
Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

Directory of Open Access Journals (Sweden)

Jianwei Li

Full Text Available Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235 specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.
An application of Six Sigma methodology to reduce the engine-overheating problem in an automotive company

Energy Technology Data Exchange (ETDEWEB)

Antony, J. [Glasgow Caledonian University (United Kingdom). Six Sigma and Process Improvement Research Centre; Kumar, M. [Glasgow Caledonian University (United Kingdom). Division of Management; Tiwari, M.K. [National Institute of Foundry and Forge Technology, Ranchi (India). Department of Manufacturing Engineering

2005-08-15

Six Sigma is a systematic methodology for continuous process quality improvement and for achieving operational excellence. The overstatement that often accompanies the presentation and adoption of Six Sigma in industry can lead to unrealistic expectations as to what Six Sigma is truly capable of achieving. This paper deals with the application of Six Sigma based methodology in eliminating an engine-overheating problem in an automotive company. The DMAIC (define-measure-analyse-improve-control) approach has been followed here to solve an underlying problem of reducing process variation and the associated high defect rate. This paper explores how a foundry can use a systematic and disciplined approach to move towards the goal of Six Sigma quality level. The application of the Six Sigma methodology resulted in a reduction in the jamming problem encountered in the cylinder head and increased the process capability from 0.49 to 1.28. The application of DMAIC has had a significant financial impact (saving over $US110 000 per annum) on the bottom-line of the company. (author)
Mystery Well: Chemical-Engineering Solution to the Internal Rain Problem.

Czech Academy of Sciences Publication Activity Database

Růžička, Marek

2017-01-01

Roč. 174, DEC 31 (2017), s. 396-402 ISSN 0009-2509 Institutional support: RVO:67985858 Keywords : precipitation * humidity-driven convection * buoyant instability Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 2.895, year: 2016

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