WorldWideScience

Sample records for subjects load research

  1. Recent Research and Applications of Numerical Simulation for Dynamic Response of Long-Span Bridges Subjected to Multiple Loads

    Directory of Open Access Journals (Sweden)

    Zhiwei Chen

    2014-01-01

    Full Text Available Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored.

  2. Suction caissons subjected to monotonic combined loading

    DEFF Research Database (Denmark)

    Penzes, P.; Jensen, M.R.; Zania, Varvara

    2016-01-01

    for offshore wind turbines. The combined loading imposed typically to a suction caisson has led to the estimation of their bearing capacity by means of 3D failure envelopes. This study aims to analyse the behaviour of suction caissons for offshore wind turbines subjected to combined loading. Finite element...

  3. Paying Hypertension Research Subjects

    Science.gov (United States)

    Casarett, David; Karlawish, Jason; Asch, David A

    2002-01-01

    CONTEXT Cash payments are often used to compensate subjects who participate in research. However, ethicists have argued that these payments might constitute an undue inducement. OBJECTIVES To determine whether potential subjects agree with theoretical arguments that a payment could be an undue inducement. DESIGN/SETTING/PARTICIPANTS Survey of 350 prospective jurors. MAIN OUTCOME MEASURES Belief that a $500 payment for research participation would impair their own, and others' ability to think carefully about the risks and benefits of a clinical trial. RESULTS Two hundred sixty-one jurors (74.6%) believed that a $500 payment would impair subjects' ability to think carefully about the risks and benefits of research. Ninety-six of 120 (80%) expressed this concern about subjects with a low income ($50,000). In contrast, only 69 (19.7%) of jurors believed that a $500 payment would influence them. Jurors who believed that this payment would influence them reported lower incomes and less education. CONCLUSION Members of the general public share ethical concerns about the influence of payments for research, although they believe that these concerns are more applicable to others than to themselves.

  4. Load research manual. Volume 1. Load research procedures

    Energy Technology Data Exchange (ETDEWEB)

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. In Volumes 1 and 2, procedures are suggested for determining data requirements for load research, establishing the size and customer composition of a load survey sample, selecting and using equipment to record customer electricity usage, processing data tapes from the recording equipment, and analyzing the data. Statistical techniques used in customer sampling are discussed in detail. The costs of load research also are estimated, and ongoing load research programs at three utilities are described. The manual includes guides to load research literature and glossaries of load research and statistical terms.

  5. Spalling of concrete subjected to blast loading

    Directory of Open Access Journals (Sweden)

    Foglar M.

    2013-09-01

    Full Text Available This paper presents outcomes of the blast field tests of FRC and reinforced concrete specimens, which were performed in cooperation with the Czech Army corps and Police of the Czech Republic in the military training area Boletice. The numerical evaluation of the experiments focused on the spalling of concrete subjected to blast loading started after the first set of the tests, took almost 3 years and required further small-scale experiments performed in the labs of the Czech Technical University.

  6. Human subjects research handbook: Protecting human research subjects. Second edition

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-30

    This handbook serves as a guide to understanding and implementing the Federal regulations and US DOE Orders established to protect human research subjects. Material in this handbook is directed towards new and continuing institutional review board (IRB) members, researchers, institutional administrators, DOE officials, and others who may be involved or interested in human subjects research. It offers comprehensive overview of the various requirements, procedures, and issues relating to human subject research today.

  7. Shock enhancement of cellular materials subjected to intensive pulse loading

    Science.gov (United States)

    Zhang, J.; Fan, J.; Wang, Z.; Zhao, L.; Li, Z.

    2017-06-01

    Cellular materials can dissipate a large amount of energy due to their considerable stress plateau, which contributes to their extensive applications in structural design for crashworthiness. However, in some experiments with specimens subjected to intense impact loads, transmitted stress enhancement has been observed, leading to severe damage to the objects protected. Transmitted stress through two-dimensional Voronoi cellular materials as a protective device is qualitatively studied in this paper. Dimensionless parameters of material properties and loading parameters are defined to give critical conditions for shock enhancement and clarify the correlation between the deformations and stress enhancement. The effect of relative density on this amplifying phenomenon is investigated as well. In addition, local strain fields are calculated by using the optimal local deformation gradient, which gives a clear presentation of deformations and possible local non-uniformity in the crushing process. This research provides valuable insight into the reliability of cellular materials as protective structures.

  8. Load research and load estimation in electricity distribution

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland). Energy Systems

    1996-12-31

    The topics introduced in this thesis are: the Finnish load research project, a simple form customer class load model, analysis of the origins of customers load distribution, a method for the estimation of the confidence interval of customer loads and Distribution Load Estimation (DLE) which utilises both the load models and measurements from distribution networks. The Finnish load research project started in 1983. The project was initially coordinated by the Association of Finnish Electric Utilities and 40 utilities joined the project. Now there are over 1000 customer hourly load recordings in a database. A simple form customer class load model is introduced. The model is designed to be practical for most utility applications and has been used by the Finnish utilities for several years. The only variable of the model is the customers annual energy consumption. The model gives the customers average hourly load and standard deviation for a selected month, day and hour. The statistical distribution of customer loads is studied and a model for customer electric load variation is developed. The model results in a lognormal distribution as an extreme case. Using the `simple form load model`, a method for estimating confidence intervals (confidence limits) of customer hourly load is developed. The two methods selected for final analysis are based on normal and lognormal distribution estimated in a simplified manner. The estimation of several cumulated customer class loads is also analysed. Customer class load estimation which combines the information from load models and distribution network load measurements is developed. This method, called Distribution Load Estimation (DLE), utilises information already available in the utilities databases and is thus easy to apply

  9. Researching Risk: Narrative, Biography, Subjectivity

    Directory of Open Access Journals (Sweden)

    Karen Henwood

    2010-01-01

    Full Text Available This article contributes to the development of methodological practices promoting greater epistemic reflexivity in risk research and in social science generally. Knowledge of the specific practices researchers will find useful cannot exist separately from any particular empirical project. Accordingly, we report on, and provide a reflective account of, the "nuclear risk" project that was part of the Social Contexts and Responses to Risk (SCARR network in the UK (2003-2008. A key focus is exploring the value of narrative methods—especially narrative elicitation methods—for understanding people's perceptions of, and ways of living with, risk. We credit our deployment of a narrative method with producing a rich form of data on risk-biography intersections, which have carried great significance in our analytical work on the way biographical experiences, dynamically unfolding through space and time, can be interrupted by risk events. Arguments from the literature on reflexive modernity are deployed to make the case for: researching risk in everyday life as a problematic in and of itself; placing concepts of risk-biography, risk-reflexivity and risk-subjectivity at centre stage; and finding ways to inquire into the social and psychic complexities involved in the dynamic construction and reconstruction of risk phenomena. URN: urn:nbn:de:0114-fqs1001201

  10. Plastic Deformation of Metal Tubes Subjected to Lateral Blast Loads

    Directory of Open Access Journals (Sweden)

    Kejian Song

    2014-01-01

    Full Text Available When subjected to the dynamic load, the behavior of the structures is complex and makes it difficult to describe the process of the deformation. In the paper, an analytical model is presented to analyze the plastic deformation of the steel circular tubes. The aim of the research is to calculate the deflection and the deformation angle of the tubes. A series of assumptions are made to achieve the objective. During the research, we build a mathematical model for simply supported thin-walled metal tubes with finite length. At a specified distance above the tube, a TNT charge explodes and generates a plastic shock wave. The wave can be seen as uniformly distributed over the upper semicircle of the cross-section. The simplified Tresca yield domain can be used to describe the plastic flow of the circular tube. The yield domain together with the plastic flow law and other assumptions can finally lead to the solving of the deflection. In the end, tubes with different dimensions subjected to blast wave induced by the TNT charge are observed in experiments. Comparison shows that the numerical results agree well with experiment observations.

  11. Temporomandibular joint loads in subjects with and without disc displacement

    Directory of Open Access Journals (Sweden)

    Laura Rei Iwasaki

    2009-12-01

    Full Text Available The likelihood of development of degenerative joint disease (DJD of the temporomandibular joint (TMJ is related to the integrity of the TMJ disc. Predilection for mechanical failure of the TMJ disc may reflect inter-individual differences in TMJ loads. Nine females and eight males in each of normal TMJ disc position and bilateral disc displacement diagnostic groups consented to participate in our study. Disc position was determined by bilateral magnetic resonance images of the joints. Three-dimensional (3D anatomical geometry of each subject was used in a validated computer-assisted numerical model to calculate ipsilateral and contralateral TMJ loads for a range of biting positions (incisor, canine, molar and angles (1-13. Each TMJ load was a resultant vector at the anterosuperior-most mediolateral midpoint on the condyle and characterized in terms of magnitude and 3D orientation. Analysis of variance (ANOVA was used to test for effects of biting position and angle on TMJ loads. Mean TMJ loads in subjects with disc displacement were 9.5-69% higher than in subjects with normal disc position. During canine biting, TMJ loads in subjects with disc displacement were 43% (ipsilateral condyle, p=0.029 and 49% (contralateral condyle, p=0.015 higher on average than in subjects with normal disc position. Biting angle effects showed that laterally directed forces on the dentition produced ipsilateral joint loads, which on average were 69% higher (p=0.002 compared to individuals with normal TMJ disc position. The data reported here describe large differences in TMJ loads between individuals with disc displacement and normal disc position. The results support future investigations of inter-individual differences in joint mechanics as a variable in the development of DJD of the TMJ.

  12. Failure of underground concrete structures subjected to blast loadings

    Science.gov (United States)

    Ross, C. A.; Nash, P. T.; Griner, G. R.

    1979-01-01

    The response and failure of two edges of free reinforced concrete slabs subjected to intermediate blast loadings are examined. The failure of the reinforced concrete structures is defined as a condition where actual separation or fracture of the reinforcing elements has occurred. Approximate theoretical methods using stationary and moving plastic hinge mechanisms with linearly varying and time dependent loadings are developed. Equations developed to predict deflection and failure of reinforced concrete beams are presented and compared with the experimental results.

  13. Physical Modelling of Bucket Foundations Subjected to Axial Loading

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina

    Compared to oil and gas structures, marine renewable energy devices are usually much lighter, operate in shallower waters and are subjected to severe cyclic loading and dynamic excitations. These factors result in different structural behaviours. Bucket foundations are a potentially cost-effectiv......Compared to oil and gas structures, marine renewable energy devices are usually much lighter, operate in shallower waters and are subjected to severe cyclic loading and dynamic excitations. These factors result in different structural behaviours. Bucket foundations are a potentially cost......-effective solution for various offshore structures, and not least marine renewables. The present thesis focuses on several critical design problems related to the behaviour of bucket foundations exposed to tensile loading. Among those are the soil-structure interface parameters, tensile loading under various...... displacement rates and tensile cyclic loading. A new laboratory testing facility is constructed allowing large scale foundation model testing under long-term cyclic loadings. Another test set-up - a pressure tank – is employed for the displacement rate analysis. The extensive testing campaign provides valuable...

  14. Single Subject Research: Applications to Special Education

    Science.gov (United States)

    Cakiroglu, Orhan

    2012-01-01

    Single subject research is a scientific research methodology that is increasingly used in the field of special education. Therefore, understanding the unique characteristics of single subject research methodology is critical both for educators and practitioners. Certain characteristics make single subject research one of the most preferred…

  15. Uplift Capacity of Inclined Underreamed Piles Subjected to Vertical Load

    Science.gov (United States)

    Rahman, Md. Akilur; Sengupta, Siddhartha

    2017-12-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Inclined (batter) piles are used to support such structures, and to carry the horizontal and vertical loads resulted from the overturning moments. Though studies have been done with inclined piles having no underream bulb, little information is available in the literature about estimating the uplift capacity of inclined underreamed piles. In the present study laboratory experiments have been done with vertically loaded model piles having no underream as well as with one and two underreams. The piles were positioned at angle of inclination of θ = 0°, 10°, 20°, 30° (with vertical); and placed in locally available sand under vertical uplift load. Three different pile stem diameters (D = 20, 25, and 35 mm) were used. The corresponding pile length to stem diameter (l/D) ratio were 18, 14, and 10 respectively. Experiments had been conducted with two relative different densities (45 and 70%) of sand. The failure uplift loads were obtained in each case. It had been found that for inclined piles increase in number of underream bulbs from 0 to 2 was quite effective in resisting uplift loads corresponding to piles having l/D equals to 10. The percentage decreases in uplift capacity corresponding to increase in inclination angle were more pronounced for piles with double underreams.

  16. Behaviour of plated structures subjected to blast loading

    Directory of Open Access Journals (Sweden)

    Aune Vegard

    2015-01-01

    Full Text Available An experimental investigation using a new shock tube facility to study blast-load effects on thin aluminium plates is presented. The shock tube is designed to expose materials and structures to extreme loading conditions, such as accidental explosions or terrorist attacks. The intensity of the loading in the present study was determined by the initial conditions of the compressed gas, i.e. volume and pressure, and the resulting loading on the target plate was compared to experimental data from explosive detonations found in the literature. The square plates were manufactured from a low-strength aluminium alloy and had an exposed area of 0.3 × 0.3 m2. Piezoelectric pressure sensors were used for pressure recordings and synchronized with two high-speed cameras operating at a frame rate of 21,000 fps in a stereoscopic setup to capture the dynamic response using a three-dimensional digital image correlation (3D-DIC technique. The experiment showed that the shock tube is capable of recreating a loading similar to that of an unconfined far-field airblast, and worked as an easily controllable alternative to explosive detonations when studying the dynamic response of structures subjected to blast loading.

  17. Subject to Form: Research Interviews, Performative Subjectivity, Professional Development

    Science.gov (United States)

    Sarigianides, Sophia Tatiana

    2010-01-01

    In this dissertation, I analyze teacher, literacy coach and researcher subjectivities in a five-year study of on-site professional development with middle-grade Language Arts teachers in a school designated by its district and state as severely underperforming. Interested in the role of research interviews as both research method and cultural…

  18. Load research manual. Volume 2. Fundamentals of implementing load research procedures

    Energy Technology Data Exchange (ETDEWEB)

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. In Volumes 1 and 2, procedures are suggested for determining data requirements for load research, establishing the size and customer composition of a load survey sample, selecting and using equipment to record customer electricity usage, processing data tapes from the recording equipment, and analyzing the data. Statistical techniques used in customer sampling are discussed in detail. The costs of load research also are estimated, and ongoing load research programs at three utilities are described. The manual includes guides to load research literature and glossaries of load research and statistical terms.

  19. Design of an Annular Disc Subject to Thermomechanical Loading

    Directory of Open Access Journals (Sweden)

    Sergei Alexandrov

    2012-01-01

    Full Text Available Two solutions to design a thin annular disc of variable thickness subject to thermomechanical loading are proposed. It is assumed that the thickness of the disc is everywhere sufficiently small for the stresses to be averaged through the thickness. The state of stress is plane. The initiation of plastic yielding is controlled by Mises yield criterion. The design criterion for one of the solutions proposed requires that the distribution of stresses is uniform over the entire disc. In this case there is a relation between optimal values of the loading parameters at the final stage. The specific shape of the disc corresponds to each pair of such parameters. The other solution is obtained under the additional requirement that the distribution of strains is uniform. This solution exists for the disc of constant thickness at specific values of the loading parameters.

  20. Progressive Failure Studies of Stiffened Panels Subjected to Shear Loading

    Science.gov (United States)

    Ambur, Damodar R.; Jaunky, Navin; Hilburger, Mark W.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Experimental and analytical results are presented for progressive failure of stiffened composite panels with and without a notch and subjected to in plane shear loading well into their postbuckling regime. Initial geometric imperfections are included in the finite element models. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Experimental results from the test include strain field data from video image correlation in three dimensions in addition to other strain and displacement measurements. Results from nonlinear finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for the stitched stiffened composite panels studied.

  1. Hydroelastic analysis of a rectangular plate subjected to slamming loads

    Science.gov (United States)

    Wang, Shan; Guedes Soares, C.

    2017-12-01

    A hydroelastic analysis of a rectangular plate subjected to slamming loads is presented. An analytical model based on Wagner theory is used for calculations of transient slamming load on the ship plate. A thin isotropic plate theory is considered for determining the vibration of a rectangular plate excited by an external slamming force. The forced vibration of the plate is calculated by the modal expansion method. Analytical results of the transient response of a rectangular plate induced by slamming loads are compared with numerical calculations from finite element method. The theoretical slamming pressure based on Wagner model is applied on the finite element model of a plate. Good agreement is obtained between the analytical and numerical results for the structural deflection of a rectangular plate due to slamming pressure. The effects of plate dimension and wave profile on the structural vibration are discussed as well. The results show that a low impact velocity and a small wetted radial length of wave yield negligible effects of hydroelasticity.

  2. Hydroelastic analysis of a rectangular plate subjected to slamming loads

    Science.gov (United States)

    Wang, Shan; Guedes Soares, C.

    2017-10-01

    A hydroelastic analysis of a rectangular plate subjected to slamming loads is presented. An analytical model based on Wagner theory is used for calculations of transient slamming load on the ship plate. A thin isotropic plate theory is considered for determining the vibration of a rectangular plate excited by an external slamming force. The forced vibration of the plate is calculated by the modal expansion method. Analytical results of the transient response of a rectangular plate induced by slamming loads are compared with numerical calculations from finite element method. The theoretical slamming pressure based on Wagner model is applied on the finite element model of a plate. Good agreement is obtained between the analytical and numerical results for the structural deflection of a rectangular plate due to slamming pressure. The effects of plate dimension and wave profile on the structural vibration are discussed as well. The results show that a low impact velocity and a small wetted radial length of wave yield negligible effects of hydroelasticity.

  3. CELEBRATING OUR SUBJECTIVITY: Research as Lived Experience

    African Journals Online (AJOL)

    When we celebrate our subjectivity we are learning new ways of telling our research tales. The research becomes a ... This paper is a celebration of learning from my research at two levels. the personal and the professional. ... some value hack into their lives. (Chairperson and parent speaking at the. Annual Let Laverton ...

  4. Thin viscoelastic disc subjected to radial non-stationary loading

    Directory of Open Access Journals (Sweden)

    Adámek V.

    2010-07-01

    Full Text Available The investigation of non-stationary wave phenomena in isotropic viscoelastic solids using analytical approaches is the aim of this paper. Concretely, the problem of a thin homogeneous disc subjected to radial pressure load nonzero on the part of its rim is solved. The external excitation is described by the Heaviside function in time, so the nonstationary state of stress is induced in the disc. Dissipative material behaviour of solid studied is represented by the discrete material model of standard linear viscoelastic solid in the Zener configuration. After the derivation of motion equations final form, the method of integral transforms in combination with the Fourier method is used for finding the problem solution. The solving process results in the derivation of integral transforms of radial and circumferential displacement components. Finally, the type of derived functions singularities and possible methods for their inverse Laplace transform are mentioned.

  5. Dynamic Stability of Columns Subjected to Follower Loads: a Survey

    Science.gov (United States)

    LANGTHJEM, M. A.; SUGIYAMA, Y.

    2000-12-01

    This paper offers a survey of simple, flexible structural elements subjected to non-conservative follower loads, such as those caused by the thrust of rocket- and jet engines, and by dry friction in automotive disk- and drum-brake systems. Emphasis is on the “canonical problems”, Beck's, Reut's, Leipholz's, and Hauger's columns. Beck's and Reut's columns have been realized experimentally, and very good agreement between theory and experiments has been found. Leipholz's column is basically realized in an automobile brake system, where noise due to dynamic or parametric instability (brake squeal) is a well-known environmental problem. It is attempted to give a broad overview, with emphasis on experimental works and the associated theoretical problems. Structural optimization is also included in the review, as many studies in that area have served an important purpose in the development of optimization techniques for practical, large-scale optimization problems with non-conservative forces, such as in aeroelasticity.

  6. Final Project Report Load Modeling Transmission Research

    Energy Technology Data Exchange (ETDEWEB)

    Lesieutre, Bernard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bravo, Richard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yinger, Robert [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chassin, Dave [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Huang, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Ning [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hiskens, Ian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Venkataramanan, Giri [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-03-31

    The research presented in this report primarily focuses on improving power system load models to better represent their impact on system behavior. The previous standard load model fails to capture the delayed voltage recovery events that are observed in the Southwest and elsewhere. These events are attributed to stalled air conditioner units after a fault. To gain a better understanding of their role in these events and to guide modeling efforts, typical air conditioner units were testing in laboratories. Using data obtained from these extensive tests, new load models were developed to match air conditioner behavior. An air conditioner model is incorporated in the new WECC composite load model. These models are used in dynamic studies of the West and can impact power transfer limits for California. Unit-level and systemlevel solutions are proposed as potential solutions to the delayed voltage recovery problem.

  7. Single-Subject Research in Gifted Education

    Science.gov (United States)

    Simonsen, Brandi; Little, Catherine A.

    2011-01-01

    Single-subject research (SSR) is an experimental research tradition that is well established in other fields (e.g., special education, behavior analysis) but has rarely been applied to topics in gifted education. In this Methodological Brief, Brandi Simonsen and Catherine A. Little from the University of Connecticut highlight the key features of…

  8. The Utility of Single Subject Design Research

    Science.gov (United States)

    Bennett, Kyle D.

    2016-01-01

    Single subject design (SSD) research is a quantitative approach used to investigate basic and applied research questions. It has been used for decades to examine issues of social importance such as those related to general and special education strategies, therapeutic approaches in mental health, community health practices, safety, and business…

  9. Finite Element Analysis of Saferooms Subjected to Tornado Impact Loads

    Science.gov (United States)

    Parfilko, Y.; Amaral de Arruda, F.; Varela, B.

    2017-10-01

    A Tornado is one of the most dreadful and unpredictable events in nature. Unfortunately, weather and geographic conditions make a large portion of the United States prone to this phenomenon. Tornado saferooms are monolithic reinforced concrete protective structures engineered to guard against these natural disasters. Saferooms must withstand impacts and wind loads from EF-5 tornadoes – where the wind speed reaches up to 150 m/s (300 mph) and airborne projectiles can reach up to 50 m/s (100 mph). The objective of this work is to evaluate the performance of a saferoom under impact from tornado-generated debris and tornado-dragged vehicles. Numerical simulations were performed to model the impact problem using explicit dynamics and energy methods. Finite element models of the saferoom, windborne debris, and vehicle models were studied using the LS-DYNA software. RHT concrete material was used to model the saferoom and vehicle models from NCAC were used to characterize damage from impacts at various speeds. Simulation results indicate good performance of the saferoom structure at vehicle impact speeds up to 25 meters per second. Damage is more significant and increases nonlinearly starting at impact velocities of 35 m/s (78 mph). Results of this study give valuable insight into the dynamic response of saferooms subjected to projectile impacts, and provide design considerations for civilian protective structures. Further work is being done to validate the models with experimental measurements.

  10. Behavior of Concrete Slab Track on Asphalt Trackbed Subjected to Thermal Load

    OpenAIRE

    Woo Young Jung; Seong Hyeok Lee; Jin Wook Lee; Bu Seog Ju

    2013-01-01

    Concrete track slab and asphalt trackbed are being introduced in Korea for providing good bearing capacity, durability to the track and comfortable rideness to passengers. Such a railway system has been designed by the train load so as to ensure stability. But there is lack of research and design for temperature changes which influence the behavior characteristics of concrete and asphalt. Therefore, in this study, the behavior characteristics of concrete track slab subjected to varying temper...

  11. Research of Impact Load in Large Electrohydraulic Load Simulator

    Directory of Open Access Journals (Sweden)

    Yongguang Liu

    2014-01-01

    Full Text Available The stronger impact load will appear in the initial phase when the large electric cylinder is tested in the hardware-in-loop simulation. In this paper, the mathematical model is built based on AMESim, and then the reason of the impact load is investigated through analyzing the changing tendency of parameters in the simulation results. The inhibition methods of impact load are presented according to the structural invariability principle and applied to the actual system. The final experimental result indicates that the impact load is inhibited, which provides a good experimental condition for the electric cylinder and promotes the study of large load simulator.

  12. Analysis of Concrete Slabs Subject to Concentrated Loads | Albrecht ...

    African Journals Online (AJOL)

    A simplified procedure for the calculation of the additional reinforcement which is required under concentrated loads acting on concrete slabs is provided. The introduced method can also be used for the treatment of line loads. Conditions for the application of this procedure are stated and tables for necessary design values ...

  13. Research Education: Perspectives and subjective processes involved in educational research

    Directory of Open Access Journals (Sweden)

    Harm H. Tillema

    2009-10-01

    Full Text Available Educational research acknowledges that researcher’s beliefs and training play a role in framing the outcomes of any study. Research not only consists of defining objectives and following certain methods (search but also of making decisions over the steps taking during the inquiry process (research.Establishing a conceptual framework to guide actions on the subjective processes in research is then crucial to control them. With that purpose in mind we offer researchers and Teacher Educators a heuristic tool to be conscious on the risks that can be taken when immersed in research interpretative process. This instrument could be utilised in PhD programs, masters and research projects.

  14. Structural behavior of SC panel subjected to impact loading using finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyuk-Kee; Kim, Seung-Eock, E-mail: sekim@sejong.ac.kr

    2015-12-15

    Highlights: • Structural behavior of SC panel subjected to impact loading is evaluated using numerical analysis. • Sensitivity studies according to fracture energy and erosion value are performed. • Analysis results are compared with impact test for SC panel. - Abstract: After the terrorist attack on the World Trade Center using aircraft in New York City in 2001, safety assessments of nuclear power plant (NPP) structures subjected to impact loading have been actively performed. Since impact tests are possible for small-scale structures but not for full-scale structures, finite element (FE) analysis is necessary for a safety assessment of NPP structure. Analysis factors such as the material model of concrete and steel, strain rate effect, concrete fracture energy, and erosion value influence the analysis results. In this paper, the effect of the concrete fracture energy and the erosion in the material model of a steel-plate concrete (SC) panel subjected to the impact loading is evaluated using the commercial software LS-DYNA. The analysis results are compared with the impact test for an SC panel conducted in other research. A quarter model of an SC panel is adopted for impact analysis. The impact force–time history is applied on the SC panel. Sensitivity studies according to the fracture energy and the erosion value are performed in order to evaluate the structural behavior of SC panels.

  15. Finite element analysis for dental implants subjected to thermal loads

    Directory of Open Access Journals (Sweden)

    Mohamad Reza Khalili

    2013-10-01

    Full Text Available   Background and Aims: Dental implants have been studied for replacement of missing teeth for many years. Productivity of implants is extremely related to the stability and resistance under applied loads and the minimum stress in jaw bone. The purpose of this study was to study numerically the 3D model of implant under thermal loads.   Materials and Methods: Bone and the ITI implant were modeled in “Solidworks” software. To obtain the exact model, the bone was assumed as a linear orthotropic material. The implant system, including implant, abutment, framework and crown were modeled and located in the bone. After importing the model in Abaqus software, the material properties and boundary conditions and loads were applied and after meshing, the model was analyzed. In this analysis, the loads were applied in two steps. In the first step, the mechanical load was applied as tightening torque to the abutment and the abutment was tightened in the implant with 35 N.cm torque. In the second step, the thermal load originated from drinking cold and hot water was applied as thermal flux on the ceramic crown surface in this model.   Results: Thermal analysis results showed that the thermal gradient in the bone was about 5.5 and 4.9 degrees of centigrade in the case of drinking cold and hot water respectively , although the maximum gradient of the whole system was reduced to 14 degrees, which occurred, in the crown by drinking cold water.   Conclusion Thermal stresses were so small and it was because of the low thermal gradient. Maximum stresses occurred in the abutment were due to the tension preloads which were originated from the tightening torque.

  16. Modeling the Damage Characteristics of Concrete Subjected to Cyclic Loadings

    Science.gov (United States)

    Ghatee, P.; Jaafar, M. S.; Ibrahim, A.; Talati, H.

    2017-11-01

    Various damage formulations have been used to simulate the inelastic behavior of granular composite materials, e.g., concrete, under cyclic loadings, but the results obtained differ from experimental data. The aim of this study is to develop general nonlinear damage formulations, with calibration capabilities, on the basis of two nonlinear indices, namely the tension and compression states, covering all cyclic loading conditions, including partial and complete unloading/reloading ones. Using verification procedures, the efficiency of calibration ability of the formulations, especially for computer programming, is illustrated.

  17. Stress and Performance: Effects of Subjective Work Load and Time Urgency.

    Science.gov (United States)

    Friend, Kenneth E.

    1982-01-01

    Measured subjective work load, time urgency, and other stress/motivation variables for management personnel taking a demanding problem-solving exam. Data suggest increases in psychological stresses like subjectively high work load and time urgency uniformly impair performance across the whole range of these variables. (Author)

  18. Durability of Adhesive Bonded Structures Subjected to Acoustic Loads,

    Science.gov (United States)

    1981-12-01

    performed on such structures in progressive-wave tubes (PWT) [5]. These tests have involved various adhesives having widely varying peel strengths and lap...loading augmented by selective progressive-wave tube tests appear to be the best approach. Riveted technology prediction methods in general are not...foematiommstum am[*l, Deopo do Servigo de Mateial Fy.Madhmatik GmibH 4a Porn Awne KeeaoemeiapmtmumRue da Eacols Pollticalca 42 D-7314 UgmunLeopdisafen 2 Lim Atn

  19. Relationship Between Pretraining Subjective Wellness Measures, Player Load, and Rating-of-Perceived-Exertion Training Load in American College Football.

    Science.gov (United States)

    Govus, Andrew D; Coutts, Aaron; Duffield, Rob; Murray, Andrew; Fullagar, Hugh

    2018-01-01

    The relationship between pretraining subjective wellness and external and internal training load in American college football is unclear. To examine the relationship of pretraining subjective wellness (sleep quality, muscle soreness, energy, wellness Z score) with player load and session rating of perceived exertion (s-RPE-TL) in American college football players. Subjective wellness (measured using 5-point, Likert-scale questionnaires), external load (derived from GPS and accelerometry), and s-RPE-TL were collected during 3 typical training sessions per week for the second half of an American college football season (8 wk). The relationship of pretraining subjective wellness with player load and s-RPE training load was analyzed using linear mixed models with a random intercept for athlete and a random slope for training session. Standardized mean differences (SMDs) denote the effect magnitude. A 1-unit increase in wellness Z score and energy was associated with trivial 2.3% (90% confidence interval [CI] 0.5, 4.2; SMD 0.12) and 2.6% (90% CI 0.1, 5.2; SMD 0.13) increases in player load, respectively. A 1-unit increase in muscle soreness (players felt less sore) corresponded to a trivial 4.4% (90% CI -8.4, -0.3; SMD -0.05) decrease in s-RPE training load. Measuring pretraining subjective wellness may provide information about players' capacity to perform in a training session and could be a key determinant of their response to the imposed training demands American college football. Hence, monitoring subjective wellness may aid in the individualization of training prescription in American college football players.

  20. Mechanical properties of two-way different configurations of prestressed concrete members subjected to axial loading

    Directory of Open Access Journals (Sweden)

    Chaobi Zhang

    2015-08-01

    Full Text Available In order to analyze the mechanical properties of two-way different configurations of prestressed concrete members subjected to axial loading, a finite element model based on the nuclear power plant containments is demonstrated. This model takes into account the influences of different principal stress directions, the uniaxial or biaxial loading, and biaxial loading ratio. The displacement-controlled load is applied to obtain the stress–strain response. The simulated results indicate that the differences of principal stress axes have great effects on the stress–strain response under uniaxial loading. When the specimens are subjected to biaxial loading, the change trend of stress with the increase of loading ratio is obviously different along different layout directions. In addition, correlation experiments and finite element analyses were conducted to verify the validity and reliability of the analysis in this study.

  1. Dream as a subject of psychological research

    Directory of Open Access Journals (Sweden)

    P.A. Egorova,

    2014-08-01

    Full Text Available We discuss the main theoretical concepts of a dream: dream definitions, ideas about its genesis, functions, dream location in the structure of activity. We analyze the similarities and differences between the approaches. The results of empirical studies of adolescent and adult dreams are generalized, dream functions in adolescence are analyzed. Based on the analysis of different approaches, we chose theoretical basis of our own research – A. Leontiev activity theory, L.S. Vygotsky concept, K. Lewin's model. We formulated and substantiated the definition of dream as emotionally colored image of the desired future, having a subjective significance. We show the significance and hypotheses of our research: 1 the content of dreams is connected not only with a situation of frustration, but also with the teenager abilities, 2 the dream is involved in regulating of values choice; 3 restoration and development of the ability to dream can be used in the practice of counseling and psychotherapy as an effective tool to help adolescents and adults

  2. Load rating and retrofit testing of bridge timber piles subjected to eccentric loading.

    Science.gov (United States)

    2012-11-01

    This report first evaluated the load rating procedure currently in use by the Illinois Department of Transportation (IDOT) for rating timber : piles supporting multiple-span, simply supported bridges. For simplicity, these piles are often rated under...

  3. Structural Stability of a Stiffened Aluminum Fuselage Panel Subjected to Combined Mechanical and Internal Pressure Loads

    Science.gov (United States)

    Rouse, Marshall; Young, Richard D.; Gehrki, Ralph R.

    2003-01-01

    Results from an experimental and analytical study of a curved stiffened aluminum panel subjected to combined mechanical and internal pressure loads are presented. The panel loading conditions were simulated using a D-box test fixture. Analytical buckling load results calculated from a finite element analysis are presented and compared to experimental results. Buckling results presented indicate that the buckling load of the fuselage panel is significantly influenced by internal pressure loading. The experimental results suggest that the stress distribution is uniform in the panel prior to buckling. Nonlinear finite element analysis results correlates well with experimental results up to buckling.

  4. Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading

    Science.gov (United States)

    Armaghani, Seyamend Bilind

    Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences

  5. Limitations of subjective cognitive load measures in simulation-based procedural training.

    Science.gov (United States)

    Naismith, Laura M; Cheung, Jeffrey J H; Ringsted, Charlotte; Cavalcanti, Rodrigo B

    2015-08-01

    The effective implementation of cognitive load theory (CLT) to optimise the instructional design of simulation-based training requires sensitive and reliable measures of cognitive load. This mixed-methods study assessed relationships between commonly used measures of total cognitive load and the extent to which these measures reflected participants' experiences of cognitive load in simulation-based procedural skills training. Two groups of medical residents (n = 38) completed three questionnaires after participating in simulation-based procedural skills training sessions: the Paas Cognitive Load Scale; the NASA Task Load Index (TLX), and a cognitive load component (CLC) questionnaire we developed to assess total cognitive load as the sum of intrinsic load (how complex the task is), extraneous load (how the task is presented) and germane load (how the learner processes the task for learning). We calculated Pearson's correlation coefficients to assess agreement among these instruments. Group interviews explored residents' perceptions about how the simulation sessions contributed to their total cognitive load. Interviews were audio-recorded, transcribed and subjected to qualitative content analysis. Total cognitive load scores differed significantly according to the instrument used to assess them. In particular, there was poor agreement between the Paas Scale and the TLX. Quantitative and qualitative findings supported intrinsic cognitive load as synonymous with mental effort (Paas Scale), mental demand (TLX) and task difficulty and complexity (CLC questionnaire). Additional qualitative themes relating to extraneous and germane cognitive loads were not reflected in any of the questionnaires. The Paas Scale, TLX and CLC questionnaire appear to be interchangeable as measures of intrinsic cognitive load, but not of total cognitive load. A more complete understanding of the sources of extraneous and germane cognitive loads in simulation-based training contexts is

  6. Modeling of failure and response to laminated composites subjected to in-plane loads

    Science.gov (United States)

    Shahid, Iqbal; Chang, Fu-Kuo

    1993-01-01

    An analytical model was developed for predicting the response of laminated composites with or without a cutout and subjected to in-plane tensile and shear loads. Material damage resulting from the loads in terms of matrix cracking, fiber-matrix shearing, and fiber breakage was considered in the model. Delamination, an out-of-plane failure mode, was excluded from the model.

  7. The behaviour of the stiff monopile foundation subjected to the lateral loads

    DEFF Research Database (Denmark)

    Lada, Aleksandra; Ibsen, Lars Bo; Nicolai, Giulio

    The article focuses on the analysis of a large-diameter monopile foundation for offshore wind turbine based on the numerical model results. The case describes the behaviour of a monopile in sand subjected to a lateral loading conditions. The effects of the pile diameter, the length and the load...

  8. Analysis of embedded waste storage tanks subjected to seismic loading

    Energy Technology Data Exchange (ETDEWEB)

    Zaslawsky, M.; Sammaddar, S.; Kennedy, W.N.

    1991-12-31

    At the Savannah River Site, High Activity Wastes are stored in carbon steel tanks that are within reinforced concrete vaults. These soil-embedded tank/vault structures are approximately 80 ft. in diameter and 40 ft. deep. The tanks were studied to determine the essentials of governing variables, to reduce the problem to the least number of governing cases to optimize analysis effort without introducing excessive conservatism. The problem reduced to a limited number of cases of soil-structure interaction and fluid (tank contents) -- structure interaction problems. It was theorized that substantially reduced input would be realized from soil structure interaction (SSI) but that it was also possible that tank-to-tank proximity would result in (re)amplification of the input. To determine the governing seismic input motion, the three dimensional SSI code, SASSI, was used. Significant among the issues relative to waste tanks is to the determination of fluid response and tank behavior as a function of tank contents viscosity. Tank seismic analyses and studies have been based on low viscosity fluids (water) and the behavior is quite well understood. Typical wastes (salts, sludge), which are highly viscous, have not been the subject of studies to understand the effect of viscosity on seismic response. The computer code DYNA3D was used to study how viscosity alters tank wall pressure distribution and tank base shear and overturning moments. A parallel hand calculation was performed using standard procedures. Conclusions based on the study provide insight into the quantification of the reduction of seismic inputs for soil structure interaction for a ``soft`` soil site.

  9. Descriptive Analysis of Single Subject Research Designs: 1983-2007

    Science.gov (United States)

    Hammond, Diana; Gast, David L.

    2010-01-01

    Single subject research methodology is commonly used and cited in special education courses and journals. This article reviews the types of single subject research designs published in eight refereed journals between 1983 and 2007 used to answer applied research questions. Single subject designs were categorized as withdrawal/reversal, time…

  10. The effect of valgus braces on medial compartment load of the knee joint - in vivo load measurements in three subjects.

    Science.gov (United States)

    Kutzner, Ines; Küther, Steffen; Heinlein, Bernd; Dymke, Jörn; Bender, Alwina; Halder, Andreas M; Bergmann, Georg

    2011-04-29

    Knee osteoarthritis occurs predominately at the medial compartment. To unload the affected compartment, valgus braces are used which induce an additional valgus moment in order to shift the load more laterally. Until now the biomechanical effect of braces was mainly evaluated by measuring changes in external knee adduction moments. The aim of this study was to investigate if and to which extent the medial compartment load is reduced in vivo when wearing valgus braces. Six components of joint contact load were measured in vivo in three subjects, using instrumented, telemeterized knee implants. From the forces and moments the medio-lateral force distribution was calculated. Two braces, MOS Genu (Bauerfeind AG) and Genu Arthro (Otto Bock) were investigated in neutral, 4° and 8° valgus adjustment during walking, stair ascending and descending. During walking with the MOS brace in 4°/8° valgus adjustment, medial forces were reduced by 24%/30% on average at terminal stance. During walking with the GA in the 8° valgus position, medial forces were reduced by only 7%. During stair ascending/descending significant reductions of 26%/24% were only observed with the MOS (8°). The load reducing ability of the two investigated valgus braces was confirmed in three subjects. However, the load reduction depends on the brace stiffness and its valgus adjustment and varies strongly inter-individually. Valgus adjustments of 8° might, especially with the MOS brace, not be tolerated by patients for a long time. Medial load reductions of more than 25% can therefore probably not be expected in clinical practise. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Experimental results for the behavior of MSMAs subjected to loads seen in power harvesting applications and complex loads

    Science.gov (United States)

    Ciocanel, C.; Feigenbaum, H. P.

    2012-04-01

    The microstructure of magnetic shape memory alloys (MSMAs) is comprised of tetragonal martensite variants, each with their preferred internal magnetization orientation. In the presence of an external magnetic field, the martensite variants tend to reorient so that the preferred internal magnetization aligns with the external magnetic field. Thus MSMAs exhibit the shape memory effect when there is a magnetic field in the vicinity of a material point. Furthermore, the tetragonal nature of the martensite variants allows for a compressive stress to cause variant reorientation. This paper focuses on the experimental evaluation of MSMAs in power harvesting as well as on the response of the material under complex loading conditions. The experimental data reported here provides a basis for the evaluation of MSMAs suitability for applications other than the traditional actuation under a constant magnetic field. For power harvesting applications, consider an MSMA element subject to a large enough magnetic field so that all the variants begin in a field preferred state. Keeping the magnetic field constant and adding a variable compressive stress in a direction normal to that of the magnetic field, some or all of the martensitic variants may rotate into a stress preferred state. As the variants reorient, the internal magnetization vectors rotate, and the specimen's magnetization changes. The change in magnetization induces a current in a pick-up coil, resulting in an output voltage at its terminals according to Faraday's law of inductance. For other applications, the loads that an MSMA element is subject to may be different. Investigation into other potential loadings of an MSMA will give a better overall understanding of the magneto-mechanical behavior of MSMAs and perhaps highlight potential applications of these materials. Thus complex loads on MSMAs should be investigated experimentally and eventually modeled mathematically. For example, this work will study variable field

  12. [Dementia - a relevant subject in psychiatric research?].

    Science.gov (United States)

    Wancata, Johannes

    2011-10-01

    Demographic change calls for increased efforts in dementia research. A systematic analysis of a German-speaking psychiatric journal was performed. 18.2 % of all papers published in were related to dementia and cognition. Dementia is a main issue; only papers regarding schizophrenia were more common. Health service research is largely lacking. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Vibration Effects of Nonclassically Damped Building-Piping Systems Subjected to Extreme Loads

    Directory of Open Access Journals (Sweden)

    YongHee Ryu

    2016-01-01

    Full Text Available Piping leakage can occur at T-joint, elbows, valves, or nozzles in nuclear power plants and nonnuclear power plants such as petrochemical plants when subjected to extreme loads and such leakage of piping systems can also lead to fire or explosion. For example, leakage of sodium, toxic gases, or nitrogen in hospitals can cause man-made hazards. The primary objective of this research is to understand the vibration effects due to classical/nonclassical damping with building-piping systems under extreme loads. The current evaluation employed finite-element analysis to calculate the effects of the responses of classically and nonclassically damped building-piping systems. Classical and nonclassical damping matrices for a coupled primary-secondary system were developed based on the Rayleigh equation. A total of 10 selected ground motions were applied to single degree of freedom (SDOF primary-SDOF secondary (2-DOF coupled systems in which the ratios of the natural frequencies between the primary and secondary systems ranged between 0.9 and 1.1. It revealed that the vibration effect of nonclassical damping was significant where the natural frequencies of the two systems were nearly tuned. For piping-material nonlinearity, the effects of nonclassical damping on the result forces of piping systems were not significantly different from those of classical damping.

  14. [Viral load test conducive to excluding negative subjects from suspects in HIV antibody detections].

    Science.gov (United States)

    Hei, Fa-Xin; Zhang, Qi-Yun; Sun, Wei-Dong; Zhang, Qin; Ye, Jing-Rong; Liu, Hai-Lin; Lu, Hong-Yan

    2008-01-01

    To study whether plasma viral load testing is helpful to exclude ones free from Human immunodeficiency virus (HIV) infections from suspects in HIV antibody detections. 19 Specimens, which showed disconcordant results of the two HIV EIA testing (S/CO test, were selected. Viral load of the specimens were detected. A six-month follow up survey in detecting HIV antibody was conducted in these subjects. None of these 19 cases was observed to be positive HIV viral loads and there was no any progress in WB bands development during the follow-up period. The possibility of HIV infection could be excluded. When the specimens react with very low intensity in both EIA and WB, negative viral load result is conducive to exclude negative subjects from suspects in HIV antibody detections.

  15. Heuristic Inquiry: Intensifying Subjectivity in Art Education Research.

    Science.gov (United States)

    Emery, Lee

    1996-01-01

    Recommends using a number of qualitative research techniques, specifically for research regarding art education teaching techniques and teachers. Argues that the process of teaching and the subject of art are so subjective that researchers should embrace unabashedly qualitative approaches to research. Briefly describes these approaches. (MJP)

  16. Resistance of Concrete Masonry Walls With Membrane Catcher Systems Subjected to Blast Loading

    Science.gov (United States)

    2010-12-01

    are made. sandwich panel, prestressed concrete , composite, test, explosive load U U U UU 22 Paul Sheppard Reset 1 Resistance of...AFRL-RX-TY-TP-2010-0090 RESISTANCE OF CONCRETE MASONRY WALLS WITH MEMBRANE CATCHER SYSTEMS SUBJECTED TO BLAST LOADING...Include area code) 29-DEC-2010 Refereed Journal Article 01-OCT-2008 -- 31-DEC-2009 Resistance of Concrete Masonry Walls With Membrane Catcher Systems

  17. Analytical and Numerical Modeling of Delamination Evolution in Fiber Reinforced Laminated Composites Subject to Flexural Loading

    Science.gov (United States)

    Xie, Jiawen

    Delamination is a common failure mode in composite (fiber reinforced and layered) structures subject to low-velocity impacts by foreign objects. To maximize the design capacity, it is important to have reliable tools to predict delamination evolution in laminated composites. The focus of this research is to analyze flexural responses and delamination evolution in laminated composites subject to flexural loading. Analytical solutions were derived from linear elasticity theory and structural mechanics of beam and plate configurations. Formulations and evaluations of the proposed analytical approaches were validated by comparing with results of finite element (FE) simulations in similar settings and published experiment data. Two-dimensional (2D) elasticity theory for laminated panels was extended to analyze elastodynamic responses of pristine panels and quasi-static responses of pre-delaminated panels. A highlight of the approach is exact solutions of displacement and stress fields it provides. Further investigations showed that the 2D elasticity theory is not amenable to a closed-form solution for laminates containing off-axis angle plies due to three-dimensional (3D) states of stress. Closed-form solutions of cohesive zone modeling (CZM) were developed for popular delamination toughness tests of laminated beams. A laminate was modeled as an assembly of two sub-laminates connected by a virtual deformable layer with infinitesimal thickness. Comprehensive parametric studies were performed, offering a deeper understanding of CZM. The studies were further simplified so that closed-form expressions can be obtained, serving as a quick estimation of the flexural responses and the process zone lengths. Analytical CZM solutions were extended analyze quasi-static impact tests of laminated composite plates with arbitrary stacking sequences, aiming to predict critical load, critical interfaces and extent of delamination at that interface. The Rayleigh-Ritz method was used to

  18. Performance of Pre-Stressed Sandwich Composites Subjected to Shock Wave Loading

    Directory of Open Access Journals (Sweden)

    Shukla A.

    2010-06-01

    Full Text Available The present paper experimentally studies the dynamic behaviour of prestressed sandwich composites under blast loading. The in-plane static compression loadings are implemented on the sandwich composites before they are subjected to the transverse shock wave loading. Three different pre-stress levels are chosen. 3-D realtime deformation data are captured by two high-speed photography systems: a backview Digital Image Correlation (DIC system and a side-view camera system. The results show that pre-stresses can induce local buckling in the front face-sheet of sandwich composites, consequently reduce the blast resistance of sandwich composites.

  19. Lifetime and residual strength of wood subjected to static and variable load

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1996-01-01

    The DVM-theory (Damaged Viscoelastic Material) previously developed by the author to predict lifetime of wood subjected to static loads is further developed in this paper such that variable loads can also be considered. Lifetime (real time or number of cycles) is predicted as a function of load...... is successfully compared with data from experiments representing different wood products. Algorithms and master graphs are developed which can be used in fatigue design of wood products in general. These graphs are valid for any creep behavior (relaxation, moisture content) and materials quality (grading...

  20. Unraveling Researcher Subjectivity Through Multivocality in Autoethnography

    Directory of Open Access Journals (Sweden)

    Robert Mizzi

    2010-01-01

    Full Text Available This article analyzes and discusses the notion of including multivocality as an autoethnographic method to: (a illustrate that there is no single and temporally-fixed voice that a researcher possesses, (b unfix identity in a way that exposes the fluid nature of identity as it moves through particular contexts, and (c deconstruct competing tensions within the autoethnographer as s/he connects the personal self to the social context. After providing a short, multivocal vignette based on the author's previous work assignment as a teacher educator in Kosovo, the author offers a reflective analysis of his approach. His analysis includes a critical discussion around the benefits and challenges of using such a method in autoethnography. The author concludes that research-oriented institutions might be resistant to validating multivocality as research practice given the myopic view that "voice" is linear, categorizable, and one-dimensional. In this way, the use of multivocality in autoethnography can also be understood as a way to liberate research practices from oppressive institutional rules and restrictions.

  1. Extrapolating Subjectivity Research to Other Languages

    Science.gov (United States)

    Banea, Carmen

    2013-01-01

    Socrates articulated it best, "Speak, so I may see you." Indeed, language represents an invisible probe into the mind. It is the medium through which we express our deepest thoughts, our aspirations, our views, our feelings, our inner reality. From the beginning of artificial intelligence, researchers have sought to impart human like…

  2. Female Entrepreneurship as Subject of Research

    Directory of Open Access Journals (Sweden)

    Almiralva Ferraz Gomes

    2014-09-01

    Full Text Available This paper’s main goal is to study the literature produced about “female entrepreneurship”, so as to scrutinize and deepen scientific reasoning referring to women entrepreneurs whilst investigating the degree of theoretical consolidation this field of knowledge has achieved. To this end, and from a critical perspective, we assessed research published in Brazilian and international journals from 1970 on, so as to offer a systematic review of the object in focus. Despite the contributions given by previous research – which does, after all, provide us with relevant information and data concerning women entrepreneurs –, most of it merely describes small segments of the female entrepreneur population, and does not advance in applying or developing theories. Moreover, in most cases, research was quantitative and empirical and attempted to draw a “profile” of women entrepreneurs. Few studies specifically carried out a theoretical analysis on the topic “gender”. Apparently, the main concern of many of these studies was to focus on the sexual structure of organizations and on its impact upon business activities. Thus, it seems appropriate to use new points-of-view to study the “female entrepreneurship” phenomenon – or, at least, to establish new ideas for investigation.

  3. "Doing death": Reflecting on the researcher's subjectivity and emotions.

    Science.gov (United States)

    Visser, Renske C

    2017-01-01

    Given that death is a universal concept, the idea that a researcher must be objective when studying this topic is common place and problematic. Thus, this article adds to the literature by discussing the complexity of subjectivity within death studies. Three key elements of subjectivity form the basis of this discussion: (a) the researcher's cultural background, (b) the researcher's personal experiences, and (c) the emotional impact of research on the researcher. It is argued that transparency about the subjective nature of death studies research can be fruitful in understanding the research process before, during, and after fieldwork.

  4. Underground verification of the large deflection performance of fibre reinforced shotcrete subjected to high stresses and convergence and to dynamic loading.

    CSIR Research Space (South Africa)

    Joughin, WC

    2002-04-01

    Full Text Available Committee Final Project Report Underground verification of the large deflection performance of fibre reinforced shotcrete subjected to high stresses and convergence and to dynamic loading W.C. Joughin, J.L. Human and P.J. Terbrugge Research agency...: Steffen, Robertson and Kirsten Project number: GAP 710 Date: April 2002 2 Executive summary The underground verification of the performance of fibre reinforced shotcrete, subject to high stresses, convergence and dynamic loading, was identified...

  5. The Use of Randomization Tests in Single-Subject Research

    Science.gov (United States)

    Haardorfer, Regine; Gagne, Phill

    2010-01-01

    Some researchers have argued for the use of or have attempted to make use of randomization tests in single-subject research. To address this tide of interest, the authors of this article describe randomization tests, discuss the theoretical rationale for applying them to single-subject research, and provide an overview of the methodological…

  6. Ethics of Research Involving Human Subjects in Criminal Justice

    Science.gov (United States)

    Bloomberg, Seth Allan; Wilkins, Leslie T.

    1977-01-01

    Research in criminal justice involving human subjects has increased greatly, yet we have no code of ethics to guide such research. This paper argues that the primary purpose of a code should be protection of these research subjects, who are especially susceptible to mistreatment because of their prisoner status. (Author)

  7. Simulation of Prestressed Concrete Sandwich Panels Subjected to Blast Loads (Preprint)

    Science.gov (United States)

    2010-02-01

    AFRL-RX-TY-TP-2010-0014 PREPRINT SIMULATION OF PRESTRESSED CONCRETE SANDWICH PANELS SUBJECTED TO BLAST LOADS Charles M. Newberry and...NUMBER (Include area code) 01-FEB-2010 Conference Paper PREPRINT 01-JAN-2009-- 31-DEC-2009 Simulation of Prestressed Concrete Sandwich Panels Subjected... concrete , sandwich panels, simulation, LS-DYNA, blast, tilt-up panels U U U UU 14 Paul Sheppard Reset Simulation of Prestressed Concrete Sandwich

  8. Allostatic load: a useful concept for advancing nursing research.

    Science.gov (United States)

    Rosemberg, Marie-Anne S; Li, Yang; Seng, Julia

    2017-12-01

    To elucidate the historical development of the allostatic load concept, alongside its use in nursing research, and to explore how allostatic load has been investigated among two stress-vulnerable populations. 'Stress' is a prominent term in understanding the development of disease. Allostatic load is among several approaches undertaken to quantify the magnitude of stress and understand how stress can affect health. We explored the advent of allostatic load including its antecedents, and consequences. We used an exemplar case to apply the concept. We reviewed studies that used allostatic load among workers and women of childbearing age. There remains a need to consolidate a common definition and operationalisation of allostatic load. Despite this need for further work, allostatic load is a good fit for nursing science which focuses on the client, environment and health. Only 12 studies explored allostatic load among workers (n = 6) and women of childbearing age (n = 6). In some studies, allostatic load was used as a predictor while in others it was used as an outcome. None of the studies considered it as a mediator. The concept of allostatic load holds promise for nursing researchers to operationalise a holistic view of multiple stressors and to quantify their effects on health. Studies are needed to affirm the role of allostatic load as a potential mediator between multiple stressors and outcomes. Longitudinal studies are also needed to demonstrate a causal pathway from stressor exposure to tertiary outcomes such as chronic conditions and morbidity. Allostatic load is a useful concept for nurses working with stress-vulnerable populations. With the use of an interpretable allostatic load index, nurses will be able to intervene at various stages of the allostasis-adaptation process (stress-response) and adjust interventions accordingly. © 2017 John Wiley & Sons Ltd.

  9. Damage & fracture of high-explosive mock subject to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cheng [Los Alamos National Laboratory; Rae, Philip J [Los Alamos National Laboratory; Cady, Carl M [Los Alamos National Laboratory; Lovato, Manuel L [Los Alamos National Laboratory

    2011-01-11

    We use four-point bend specimen with a single shallow edge notch to study the fracture process in Mock 900-21, a PBX 9501 high explosive simulant mock. Subject to monotonic loading we determine quantitatively the threshold load for macroscopic crack initiation from the notch tip. The four-point bend specimen is then subject to cyclic loading in such a way that during the first cycle, the applied force approaches but does not exceed the threshold load determined from the monotonic loading test and in the subsequent cycles, the overall maximum deformation is maintained to be equal to that of the first cycle. It is expected and is also confirmed that no macroscopic damage and cracking occur during the first cycle. However, we observe that sizable macroscopic crack is generated and enlarged during the subsequent cycles, even though the applied force never exceeds the threshold load. Details of the process of damage fonnation, accumulation, and crack extension are presented and the mechanical mechanism responsible for such failure process is postulated and discussed.

  10. Predicting the residual strength of open-hole (OH) composite specimens subjected to cyclic loading

    Science.gov (United States)

    Ceparano, Angelo; Dell'Aversano, Raffaella

    2016-05-01

    A procedure is reported that allows the prediction of the fatigue life and the residual strength of "open hole" composite specimens subjected to constant amplitude cyclic loadings. Based on a two-parameter phenomenological model explicitly accounting for the maximum applied stress, σmax, and the stress ratio, R, the procedure relies on a relatively small set of experimental fatigue life data. The approach reliability is checked in predicting the fatigue life and residual strength of AS4 carbon/epoxy 3k/E7K8 Plain Weave Fabric "open-hole" (OH) samples subjected to a very broad loading conditions from prevailing tension (R=0 and R=-0.2) to compression (R=5) to mixed tension/compression (R=-1) loadings.

  11. Deformation response of gellan gum based bone scaffold subjected to uniaxial quasi-static loading

    Czech Academy of Sciences Publication Activity Database

    Kytýř, Daniel; Krčmářová, Nela; Šleichrt, Jan; Fíla, Tomáš; Koudelka_ml., Petr; Gantar, A.; Novak, S.

    2017-01-01

    Roč. 57, č. 1 (2017), s. 14-21 ISSN 1210-2709 EU Projects: European Commission(XE) ATCZ38 Institutional support: RVO:68378297 Keywords : gellan gum scaffold * reinforcement * uni-axial loading Subject RIV: JJ - Other Materials https://ojs.cvut.cz/ojs/index.php/ap/article/view/3885

  12. Dynamic Response of Offshore Wind Turbines subjected to Joint Wave and Wind Loads

    DEFF Research Database (Denmark)

    Liu, Weiliang; Chen, Jianbing; Liu, Wenfeng

    2013-01-01

    This paper investigates the dynamic response of offshore wind turbine systems subjected joint wind and wave loads. Relying on the finite element model, Kane’s equation is adopted to consider the rotation of blades. Besides, the generator-torque control and blade-pitch control are taken into consi...

  13. Analysis of an adhesively bonded single lap joint subjected to eccentric loading

    DEFF Research Database (Denmark)

    Anyfantis, Konstantinos; Tsouvalis, N. G.

    2013-01-01

    is benchmarking of computational tools. The test is based on a Single Lap Joint subjected to Eccentric Loading (SLJ-EL). The basic concept that lies behind this configuration is that the applied in-plane tensile load leads the adhesive layer to develop normal stresses, in-plane and out-of-plane shear stresses......A new experimental test is proposed, which allows the contribution of Mode I, II and III fracture modes to the failure of the adhesive layer of bonded joints aiming at achieving the realistic conditions often occurring during loading of practical joints. The main objective of this test......, which correspond to Mode I, II and III loading and fracture. These tests were designed so that the metal substrates do not enter plasticity and the adhesive achieves a mode mixity ratio between Mode II and Mode III not lower than 0.5. The experiments were simulated in a 3-dimensional finite element...

  14. Ascorbic acid prevents vascular dysfunction induced by oral glucose load in healthy subjects.

    Science.gov (United States)

    De Marchi, Sergio; Prior, Manlio; Rigoni, Anna; Zecchetto, Sara; Rulfo, Fanny; Arosio, Enrico

    2012-01-01

    To examine the effects of oral glucose load on forearm circulatory regulation before and after ascorbic acid administration in healthy subjects. Microcirculation study with laser Doppler was performed at the hand in basal conditions, after ischemia and after acetylcholine and nitroprusside; strain gauge plethysmography was performed at basal and after ischemia. The tests were repeated in the same sequence 2 hour after oral administration of glucose (75 g). The subjects were randomised for administration of ascorbic acid (1 g bid) or placebo (sodium bicarbonate 1 g bid) for 10 days. After that, the tests were repeated before and after a new oral glucose load. Blood pressure and heart rate were monitored. Macrocirculatory flux, pressure values and heart rate were unvaried throughout the study. The glucose load caused a reduction in the hyperemic peak flow with laser Doppler and plethysmography; it reduced flux recovery time and hyperemic curve area after ischemia; acetylcholine elicited a minor increase in flux with laser Doppler. The response to nitroprusside was unvaried after glucose load as compared to basal conditions. Treatment with ascorbic acid prevented the decrease in hyperemia after glucose, detected with laser Doppler and plethysmography. Ascorbic acid prevented the decreased response to acetylcholine after glucose, the response to nitroprusside was unaffected by ascorbic acid. Results after placebo were unvaried. Oral glucose load impairs endothelium dependent dilation and hyperaemia at microcirculation, probably via oxidative stress; ascorbic acid can prevent it. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  15. Development of a new connection for precast concrete walls subjected to cyclic loading

    Science.gov (United States)

    Vaghei, Ramin; Hejazi, Farzad; Taheri, Hafez; Jaafar, Mohd Saleh; Aziz, Farah Nora Aznieta Abdul

    2017-01-01

    The Industrialized Building System (IBS) was recently introduced to minimize the time and cost of project construction. Accordingly, ensuring the integration of the connection of precast components in IBS structures is an important factor that ensures stability of buildings subjected to dynamic loads from earthquakes, vehicles, and machineries. However, structural engineers still lack knowledge on the proper connection and detailed joints of IBS structure construction. Therefore, this study proposes a special precast concrete wall-to-wall connection system for dynamic loads that resists multidirectional imposed loads and reduces vibration effects (PI2014701723). This system is designed to connect two adjacent precast wall panels by using two steel U-shaped channels (i.e., male and female joints). During casting, each joint is adapted for incorporation into a respective wall panel after considering the following conditions: one side of the steel channel opens into the thickness face of the panel; a U-shaped rubber is implemented between the two channels to dissipate the vibration effect; and bolts and nuts are used to create an extension between the two U-shaped male and female steel channels. The developed finite element model of the precast wall is subjected to cyclic loads to evaluate the performance of the proposed connection during an imposed dynamic load. Connection performance is then compared with conventional connections based on the energy dissipation, stress, deformation, and concrete damage in the plastic range. The proposed precast connection is capable of exceeding the energy absorption of precast walls subjected to dynamic load, thereby improving its resistance behavior in all principal directions.

  16. Experimental and numerical investigation of slabs on ground subjected to concentrated loads

    Science.gov (United States)

    Øverli, Jan

    2014-09-01

    An experimental program is presented where a slab on ground is subjected to concentrated loading at the centre, the edges and at the corners. Analytical solutions for the ultimate load capacity fit well with the results obtained in the tests. The non-linear behaviour of the slab is captured by performing nonlinear finite element analyses. The soil is modelled as a no-tension bedding and a smeared crack approach is employed for the concrete. Through a parametric study, the finite element model has been used to assess the influence of subgrade stiffness and shrinkage. The results indicate that drying shrinkage can cause severe cracking in slabs on grade.

  17. Stability of Monolithic Rubble Mound Breakwater Crown Walls Subjected to Impulsive Loading

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke

    2012-01-01

    This paper evaluates the validity of a simple onedimensional dynamic analysis as well as a FEM model to determine the sliding of a rubble mound breakwater crown wall. The evaluation is based on a case example with real wave load time series and displacements measured from two-dimensional physical...... model tests. The outcome is a more reliable evaluation of the applicability of simple dynamic calculations for the estimation of sliding distances of rubble mound superstructures. This is of great practical importance since many existing rubble mound crown walls are subjected to increasing wave loads...

  18. Dynamic Behaviours of a Single Soft Rock-Socketed Shaft Subjected to Axial Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Ben-jiao Zhang

    2016-01-01

    Full Text Available The soft rock was simulated by cement, plaster, sand, water, and concrete hardening accelerator in this paper. Meanwhile, uniaxial compressive strength tests and triaxial compression tests were conducted to study the mechanical properties of simulated soft rock samples. Model tests on a single pile socketed in simulated soft rock under axial cyclic loading were conducted by using a device which combined test apparatus with a GCTS dynamic triaxial system. Test results show that the optimal mix ratio is cement : plaster : medium sand : water : concrete hardening accelerator = 4.5% : 5.0% : 84.71% : 4.75% : 1.04%. The static load ratio (SLR, cyclic load ratio (CLR, and the number of cycles affect the accumulated deformation and cyclic secant modulus of the pile head. The accumulated deformation increases with increasing numbers of cycles. However, the cyclic secant modulus of pile head increases and then decreases with the growth in the number of cycles and finally remains stable after 50 cycles. According to the test results, the development of accumulated settlement was analysed. Finally, an empirical formula for accumulated settlement, considering the effects of the number of cycles, the static load ratio, the cyclic load ratio, and the uniaxial compressive strength, is proposed which can be used for feasibility studies or preliminary design of pile foundations on soft rock subjected to traffic loading.

  19. Effects of the Tip Location on Single Piles Subjected to Surcharge and Axial Loads

    Directory of Open Access Journals (Sweden)

    Yaru Lv

    2013-01-01

    Full Text Available When applying axial load on piles subjected to negative skin friction (NSF, the yielded NSF is gradually eliminated. The process is notably influenced by the tip location (Y and still a lack of understanding. This paper reports three-dimensional numerical simulations with tip locations Y=1.00 pile diameter (D, 0.25D, 0.00D, and -1.00D. It is found that, against expectations, the dragload and NSF are not proportionally related to the tip location. When maximum dragload (Pmax is eventually eliminated due to an axial load, there is also a negative crest of the skin friction, indicating that NSF still exists based on the criterion of the dragload reduction. The side resistance of the piles with Y=1.00D and 0.25D is almost fully mobilised, which is demonstrated by the increment of end resistance that greatly increases with the larger axial loads. However, the side resistance of the piles with Y=0.00D and -1.00D has a potential capacity to carry more loads with continued displacement since the increment of end resistance increases almost linearly with axial load. Therefore, when designing the pile foundation, the inclusion of the NSF should be governed by the amount of axial load to be resisted.

  20. Effects of the tip location on single piles subjected to surcharge and axial loads.

    Science.gov (United States)

    Lv, Yaru; Ding, Xuanming; Wang, Dubo

    2013-01-01

    When applying axial load on piles subjected to negative skin friction (NSF), the yielded NSF is gradually eliminated. The process is notably influenced by the tip location (Y) and still a lack of understanding. This paper reports three-dimensional numerical simulations with tip locations Y = 1.00 pile diameter (D), 0.25D, 0.00D, and -1.00D. It is found that, against expectations, the dragload and NSF are not proportionally related to the tip location. When maximum dragload (P max) is eventually eliminated due to an axial load, there is also a negative crest of the skin friction, indicating that NSF still exists based on the criterion of the dragload reduction. The side resistance of the piles with Y = 1.00D and 0.25D is almost fully mobilised, which is demonstrated by the increment of end resistance that greatly increases with the larger axial loads. However, the side resistance of the piles with Y = 0.00D and -1.00D has a potential capacity to carry more loads with continued displacement since the increment of end resistance increases almost linearly with axial load. Therefore, when designing the pile foundation, the inclusion of the NSF should be governed by the amount of axial load to be resisted.

  1. Sands subjected to repetitive vertical loading under zero lateral strain: accumulation models, terminal densities, and settlement

    KAUST Repository

    Chong, Song Hun

    2016-08-09

    Geosystems often experience numerous loading cycles. Plastic strain accumulation during repetitive mechanical loads can lead to shear shakedown or continued shear ratcheting; in all cases, volumetric strains diminish as the specimen evolves towards terminal density. Previously suggested models and new functions are identified to fit plastic strain accumulation data. All accumulation models are formulated to capture terminal density (volumetric strain) and either shakedown or ratcheting (shear strain). Repetitive vertical loading tests under zero lateral strain conditions are conducted using three different sands packed at initially low and high densities. Test results show that plastic strain accumulation for all sands and density conditions can be captured in the same dimensionless plot defined in terms of the initial relative density, terminal density, and ratio between the amplitude of the repetitive load and the initial static load. This observation allows us to advance a simple but robust procedure to estimate the maximum one-dimensional settlement that a foundation could experience if subjected to repetitive loads. © 2016, Canadian Science Publishing. All rights reserved.

  2. Subjectivity and Reflexivity: Locating the Self in Research on Dislocation

    Science.gov (United States)

    Mosselson, Jacqueline

    2010-01-01

    I argue in this article that recognizing the role of subjectivity and bringing in the researcher's positionality as a tool in the research process can not only enhance the ethical integrity of the research but also enhance both the research process and the analysis and interpretation of the data. Cultural studies theorists have long argued that…

  3. Human subject research for engineers a practical guide

    CERN Document Server

    de Winter, Joost C F

    2017-01-01

    This Brief introduces engineers to the main principles in ethics, research design, statistics, and publishing of human subject research. In recent years, engineering has become strongly connected to disciplines such as biology, medicine, and psychology. Often, engineers (and engineering students) are expected to perform human subject research. Typical human subject research topics conducted by engineers include human-computer interaction (e.g., evaluating the usability of software), exoskeletons, virtual reality, teleoperation, modelling of human behaviour and decision making (often within the framework of ‘big data’ research), product evaluation, biometrics, behavioural tracking (e.g., of work and travel patterns, or mobile phone use), transport and planning (e.g., an analysis of flows or safety issues), etc. Thus, it can be said that knowledge on how to do human subject research is indispensable for a substantial portion of engineers. Engineers are generally well trained in calculus and mechanics, but m...

  4. Experimental Analysis of Repaired Masonry Elements with Flax-FRCM and PBO-FRCM Composites Subjected to Axial Bending Loads

    Directory of Open Access Journals (Sweden)

    Oscar A. Cevallos

    2015-11-01

    Full Text Available In the construction industry, the use of natural fabrics as a reinforcement for cement-based composites has shown great potential. The use of these sustainable composites to provide strengthening or repair old masonry structures that exhibit structural problems mainly due to a poor tensile strength of the mortar/brick joints is revealed to be a promising area of research. One of the most significant load conditions affecting the mechanical response of masonry structures occurs when axial bending loads are applied on the resistant cross-section. In this study, three different types of masonry elements were built using clay bricks and a lime-based mortar. After 28 days, the samples were subjected to concentric and eccentric compressive loads. In order to produce significant bending effects, the compressive loads were applied with large eccentricity, and a sudden failure characterized the behavior of the unreinforced masonry (URM elements. The tested masonry specimens were repaired using fabric-reinforced cementitious matrix (FRCM composites produced using bi-directional flax and polyparaphenylene benzobisoxazole (PBO fabrics. The mechanical behavior of the URM and repaired samples was compared in terms of load-displacement and moment-curvature responses. Furthermore, the results achieved using flax-FRCM composites were compared with those of using PBO-FRCM composites.

  5. In-situ quasi-static and dynamic behavioural response of steel tubular frames subjected to lateral impact loads

    Directory of Open Access Journals (Sweden)

    M. Zeinoddini

    Full Text Available Steel tubular members are widely used as primary and secondary structural framing members in offshore oil and gas platforms. A platform is inherently liable to collisions from ships which can create severe structural damages in the rig. The effect of this damage has been studied by a number of researchers through investigating the impact behaviour isolated tubular members. This is while, the in-situ response of a member located in a structural frame, to lateral impact loads, is not necessarily the same as the response of an individual isolated impacted member. In this paper the behaviour of a chord member forming part of a tubular frame, subjected to impact loads, has been investigated. The tubular frame was tested experimentally by other researchers and reported in the literature. The non-linear numerical models of the frame presented by the authors have been validated against the experimental results. These validated models have been examined under both quasi-static and dynamic impact loads with operational pre-loading applied. It has been found that, in a pre-loaded frame, quasi-static impact loading results in the failure of the impacted member. Interestingly, dynamic modelling of the impact results in the dynamic instability of an adjacent bracing member. It has been noticed that, under a dynamic impact, the impacted in-situ member (located in the frame behaves rather similarly to a pin ended isolated member. With a quasi-static impact, the impacted in-situ member follows fairly closely the response obtained for a fixed ended isolated member.

  6. Further Study on Strain Growth in Spherical Containment Vessels Subjected to Internal Blast Loading

    OpenAIRE

    2009-01-01

    Abstract Strain growth is a phenomenon observed in the elastic response of containment vessels subjected to internal blast loading, which is featured by the increased vibration amplitude of the vessel in a later stage. Previous studies attributed the strain growth in spherical containment vessels to the beating between two close vibration modes, the interactions between the vessel vibration and the reflected shock waves and the structural perturbation. In this paper, it is shown th...

  7. Electromechanical characterization of piezoelectric actuators subjected to a variable pre-loading force at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Fouaidy, M.; Saki, M.; Hammoudi, N.; Simonet, L. [IPN, CNRS-IN2P3, Orsay (France)

    2007-07-01

    A dedicated apparatus was designed and constructed for studying the electromechanical behavior of prototype piezoelectric actuators subjected to a variable pre-loading force at cryogenic temperatures. This device was successfully used for testing a piezoelectric actuator of PICMA type from PI{sup TM}, for T in the range 2 K-300 K. The dielectric properties as well as dynamic properties were measured including the actuator characteristics when used as force sensor. The corresponding data are reported and discussed. (authors)

  8. RESEARCH OF PARAMETERS PRISMATIC PLACEHOLDER WITH THE STATIC LOADING

    Directory of Open Access Journals (Sweden)

    O. M. Ustarkhanov

    2014-01-01

    Full Text Available The work is devoted to experimental research of parameters of prismatic aggregate at static loading. The data of experimental researches allow to use them in the design of three-layer structures in space, aviation techniques, as well as in construction and machinery that is of interest for technical workers and designers.

  9. On strength design using free material subjected to multiple load cases

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2013-01-01

    Multiple load cases and the consideration of strength is a reality that most structural designs are exposed to. Improved possibility to produce specific materials, say by fiber lay-up, put focus on research on free material optimization. A formulation for such design problems together with a prac......Multiple load cases and the consideration of strength is a reality that most structural designs are exposed to. Improved possibility to produce specific materials, say by fiber lay-up, put focus on research on free material optimization. A formulation for such design problems together...... with a practical recursive design procedure is presented and illustrated with examples. The presented finite element analysis involve many elements as well as many load cases. Separating the local amount of material from a description with unit trace for the local anisotropy, gives the free materials formulation...

  10. Structural Technology Evaluation and Analysis Program (STEAP). Delivery Order 0046: Multiscale Modeling of Composite Structures Subjected to Cyclic Loading

    Science.gov (United States)

    2012-09-01

    reinforced composites, cyclic loading, fatigue loading, spatial scale effects, X-ray radiography , X-ray computed tomography 16. SECURITY CLASSIFICATION...5 3.1.4 X-ray Radiography ......................................................................................... 5...Subjected to Cyclic Loading ................................................................................................ 50 24 Quasi-isotropic Virtual

  11. Experimental Testing of Monopiles in Sand Subjected to One-Way Long-Term Cyclic Lateral Loading

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2013-01-01

    In the offshore wind turbine industry the most widely used foundation type is the monopile. Due to the wave and wind forces the monopile is subjected to a strong cyclic loading with varying amplitude, maximum loading level, and varying loading period. In this paper the soil–pile interaction...

  12. Lacan, Subjectivity and the Task of Mathematics Education Research

    Science.gov (United States)

    Brown, Tony

    2008-01-01

    This paper addresses the issue of subjectivity in the context of mathematics education research. It introduces the psychoanalyst and theorist Jacques Lacan whose work on subjectivity combined Freud's psychoanalytic theory with processes of signification as developed in the work of de Saussure and Peirce. The paper positions Lacan's subjectivity…

  13. 76 FR 44512 - Human Subjects Research Protections: Enhancing Protections for Research Subjects and Reducing...

    Science.gov (United States)

    2011-07-26

    ... organizations (CROs), data and safety monitoring committees, community-based organizations, and other entities... neuroscience has led to substantial advances in the understanding of human physiology, cognition, and behavior... subjects? What entity or organization should develop and disseminate such standardized document formats...

  14. Incorporation of CT-based measurements of trunk anatomy into subject-specific musculoskeletal models of the spine influences vertebral loading predictions.

    Science.gov (United States)

    Bruno, Alexander G; Mokhtarzadeh, Hossein; Allaire, Brett T; Velie, Kelsey R; De Paolis Kaluza, M Clara; Anderson, Dennis E; Bouxsein, Mary L

    2017-10-01

    We created subject-specific musculoskeletal models of the thoracolumbar spine by incorporating spine curvature and muscle morphology measurements from computed tomography (CT) scans to determine the degree to which vertebral compressive and shear loading estimates are sensitive to variations in trunk anatomy. We measured spine curvature and trunk muscle morphology using spine CT scans of 125 men, and then created four different thoracolumbar spine models for each person: (i) height and weight adjusted (Ht/Wt models); (ii) height, weight, and spine curvature adjusted (+C models); (iii) height, weight, and muscle morphology adjusted (+M models); and (iv) height, weight, spine curvature, and muscle morphology adjusted (+CM models). We determined vertebral compressive and shear loading at three regions of the spine (T8, T12, and L3) for four different activities. Vertebral compressive loads predicted by the subject-specific CT-based musculoskeletal models were between 54% lower to 45% higher from those estimated using musculoskeletal models adjusted only for subject height and weight. The impact of subject-specific information on vertebral loading estimates varied with the activity and spinal region. Vertebral loading estimates were more sensitive to incorporation of subject-specific spinal curvature than subject-specific muscle morphology. Our results indicate that individual variations in spine curvature and trunk muscle morphology can have a major impact on estimated vertebral compressive and shear loads, and thus should be accounted for when estimating subject-specific vertebral loading. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2164-2173, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Subject reactivity effects and alcohol treatment outcome research.

    Science.gov (United States)

    Clifford, P R; Maisto, S A

    2000-11-01

    Attributions regarding alcohol treatment research protocols influencing clinical outcomes have persisted for more than 25 years. Although well-designed alcohol treatment outcome studies typically involve frequent, and often comprehensive, research assessment protocols, procedures are seldom in place to control or account for possible subject reactivity to the research protocol. This article presents a theoretical basis for a relationship between research protocols and treatment outcomes. The article reviews the relevant alcohol treatment outcome literature and presents a "weight of evidence" regarding subject reactivity effects and alcohol treatment outcome research assessment protocols. Also, the FRAMES (feedback, responsibility, advice, menu, empathy and self-efficacy) model was coupled with self-regulation theory to provide a theoretical explanation of how research assessment protocols might contribute to clinically relevant behavioral change. Researcher attributions, empirical investigations and theoretical considerations all provide evidence that is consistent with the existence of subject reactivity to research assessment protocols. Recommendations are made regarding interpretation of data collected as part of an alcohol treatment outcome study, control of potential subject reactivity confounding variables and directions for future research.

  16. Performance of Hybrid Steel Fibers Reinforced Concrete Subjected to Air Blast Loading

    Directory of Open Access Journals (Sweden)

    Mohammed Alias Yusof

    2013-01-01

    Full Text Available This paper presents the results of the experimental data and simulation on the performance of hybrid steel fiber reinforced concrete (HSFRC and also normal reinforced concrete (NRC subjected to air blast loading. HSFRC concrete mix consists of a combination of 70% long steel hook end fibre and also 30% of short steel hook end fibre with a volume fraction of 1.5% mix. A total of six concrete panels were subjected to air blast using plastic explosive (PE4 weighing 1 kg each at standoff distance of 0.3 meter. The parameters measured are mode of failure under static and blast loading and also peak overpressure that resulted from detonation using high speed data acquisition system. In addition to this simulation work using AUTODYN was carried out and validated using experimental data. The experimental results indicate that hybrid steel fiber reinforced concrete panel (HSFRC possesses excellent resistance to air blast loading as compared to normal reinforced concrete (NRC panel. The simulation results were also found to be close with experimental data. Therefore the results have been validated using experimental data.

  17. Behavior of Steel-Sheathed Shear Walls Subjected to Seismic and Fire Loads.

    Science.gov (United States)

    Hoehler, Matthew S; Smith, Christopher M; Hutchinson, Tara C; Wang, Xiang; Meacham, Brian J; Kamath, Praveen

    2017-07-01

    A series of tests was conducted on six 2.7 m × 3.7 m shear wall specimens consisting of cold-formed steel framing sheathed on one side with sheet steel adhered to gypsum board and on the opposite side with plain gypsum board. The specimens were subjected to various sequences of simulated seismic shear deformation and fire exposure to study the influence of multi-hazard interactions on the lateral load resistance of the walls. The test program was designed to complement a parallel effort at the University of California, San Diego to investigate a six-story building subjected to earthquakes and fires. The test results reported here indicate that the fire exposure caused a shift in the failure mode of the walls from local buckling of the sheet steel in cases without fire exposure, to global buckling of the sheet steel with an accompanying 35 % reduction in lateral load capacity after the wall had been exposed to fire. This behavior appears to be predictable, which is encouraging from the standpoint of residual lateral load capacity under these severe multi-hazard actions.

  18. Predicting the Reliability of Brittle Material Structures Subjected to Transient Proof Test and Service Loading

    Science.gov (United States)

    Nemeth, Noel N.; Jadaan, Osama M.; Palfi, Tamas; Baker, Eric H.

    Brittle materials today are being used, or considered, for a wide variety of high tech applications that operate in harsh environments, including static and rotating turbine parts, thermal protection systems, dental prosthetics, fuel cells, oxygen transport membranes, radomes, and MEMS. Designing brittle material components to sustain repeated load without fracturing while using the minimum amount of material requires the use of a probabilistic design methodology. The NASA CARES/Life 1 (Ceramic Analysis and Reliability Evaluation of Structure/Life) code provides a general-purpose analysis tool that predicts the probability of failure of a ceramic component as a function of its time in service. This capability includes predicting the time-dependent failure probability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The developed methodology allows for changes in material response that can occur with temperature or time (i.e. changing fatigue and Weibull parameters with temperature or time). For this article an overview of the transient reliability methodology and how this methodology is extended to account for proof testing is described. The CARES/Life code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  19. Different Serum Free Fatty Acid Profiles in NAFLD Subjects and Healthy Controls after Oral Fat Load

    Directory of Open Access Journals (Sweden)

    Roberto Gambino

    2016-03-01

    Full Text Available Background: Free fatty acid (FFA metabolism can impact on metabolic conditions, such as obesity and nonalcoholic fatty liver disease (NAFLD. This work studied the increase in total FFA shown in NAFLD subjects to possibly characterize which fatty acids significantly accounted for the whole increase. Methods: 21 patients with NAFLD were selected according to specified criteria. The control group consisted of nine healthy subjects. All subjects underwent an oral standard fat load. Triglycerides; cholesterol; FFA; glucose and insulin were measured every 2 h with the determination of fatty acid composition of FFA. Results: higher serum FFA levels in NAFLD subjects are mainly due to levels of oleic, palmitic and linoleic acids at different times. Significant increases were shown for docosahexaenoic acid, linolenic acid, eicosatrienoic acid, and arachidonic acid, although this was just on one occasion. In the postprandial phase, homeostatic model assessment HOMA index positively correlated with the ω3/ω6 ratio in NAFLD patients. Conclusions: the higher serum levels of FFA in NAFLD subjects are mainly due to levels of oleic and palmitic acids which are the most abundant circulating free fatty acids. This is almost exactly corresponded with significant increases in linoleic acid. An imbalance in the n-3/n-6 fatty acids ratio could modulate postprandial responses with more pronounced effects in insulin-resistant subjects, such as NAFLD patients.

  20. Commercial building energy use monitoring for utility load research

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchi, R.P.

    1987-01-01

    This paper describes a method to acquire empirical data regarding commercial building energy performance for utility load research. The method was devised and implemented for a large scale monitoring program being conducted for a federal electricity marketing and transmission agency in the Pacific Northwest states. An important feature of this method is its hierarchical approach, wherein building types, end-use loads, and key building characteristics are classified to accommodate analysis at many levels. Through this common taxonomy and measurement protocol, energy-use metering projects of varying detail and comprehensiveness can be coordinated. The procedures devised for this project have been implemented for approximately 150 buildings to date by specially trained contractors. Hence, this paper provides real-world insights of the complexity and power of end use measurements from commercial buildings to address utility load research topics. 6 refs.

  1. Subjective Response to Alcohol as a Research Domain Criterion.

    Science.gov (United States)

    Ray, Lara A; Bujarski, Spencer; Roche, Daniel J O

    2016-01-01

    Individual differences in the subjective experience of the pharmacological effects of alcohol have long been implicated in the likelihood that one will drink heavily and develop alcoholism. The theme of this conceptual review and perspective article is to synthesize the literature on subjective responses to alcohol and to set an agenda for the next generation of research in the area. Specifically, we contend that in order for subjective response to alcohol to play a prominent role in alcoholism research, it is critical that it be studied as a multimodal phenotype. First, we review the human research on subjective response to alcohol measured under controlled laboratory conditions and draw recommendations for the application of these findings to understanding alcoholism neurobiology in humans. Second, we highlight multimodal approaches, including studies of the genetic and neural substrates of individual differences in subjective response to alcohol. Third, we review treatment implications with a focus on subjective response to alcohol as an intervention target. Upon review of the research on subjective response to alcohol across levels of analyses, we provide recommendations for leveraging these phenotypes in a systematic and methodologically rigorous fashion that can address central questions about alcoholism etiology, disease progression, and personalized treatment. The approach recommended herein is largely consistent with the Research Domain Criteria (RDoC) initiative across the National Institute of Mental Health. The defining feature of such domains is that they inform behavior yet be amenable to examination through multiple units of analysis, such as molecular, genetic, circuit-level, and behavioral measurements. To that end, we contend that subjective response to alcohol represents a behaviorally and biologically plausible phenotype upon which to build using the RDoC framework for understanding alcohol use disorder. Copyright © 2016 by the Research Society

  2. Subject Didactic Studies of Research Training in Biology and Physics.

    Science.gov (United States)

    Lybeck, Leif

    1984-01-01

    The objectives and design of a 3-year study of research training and supervision in biology and physics are discussed. Scientific problems arising from work on the thesis will be a focus for the postgraduate students and their supervisors. Attention will be focused on supervisors' and students' conceptions of science, subject range, research,…

  3. Rigid-Plastic Approximations for Predicting Plastic Deformation of Cylindrical Shells Subject to Dynamic Loading

    Directory of Open Access Journals (Sweden)

    Michelle S. Hoo Fatt

    1996-01-01

    Full Text Available A theoretical approach was developed for predicting the plastic deformation of a cylindrical shell subject to asymmetric dynamic loads. The plastic deformation of the leading generator of the shell is found by solving for the transverse deflections of a rigid-plastic beam/string-on-foundation. The axial bending moment and tensile force in the beam/string are equivalent to the longitudinal bending moments and membrane forces of the shell, while the plastic foundation force is equivalent to the shell circumferential bending moment and membrane resistances. Closed-form solutions for the transient and final deformation profile of an impulsive loaded shell when it is in a “string” state were derived using the eigenfunction expansion method. These results were compared to DYNA 3D predictions. The analytical predictions of the transient shell and final centerline deflections were within 25% of the DYNA 3D results.

  4. Damage propagation in a masonry arch subjected to slow cyclic and dynamic loadings

    Directory of Open Access Journals (Sweden)

    J. Toti

    2014-07-01

    Full Text Available In the present work, the damage propagation of a masonry arch induced by slow cyclic and dynamic loadings is studied. A two-dimensional model of the arch is proposed. A nonlocal damage-plastic constitutive law is adopted to reproduce the hysteretic characteristics of the masonry material, subjected to cyclic static loadings or to harmonic dynamic excitations. In particular, the adopted cohesive model is able to take into account different softening laws in tension and in compression, plastic strains, stiffness recovery and loss due to crack closure and reopening. The latter effect is an unavoidable feature for realistically reproducing hysteretic cycles. In the studied case, an inverse procedure is used to calibrate the model parameters. Then, nonlinear static and dynamic responses of the masonry arch are described together with damage propagation paths.

  5. Damage Simulation in Non-Crimp Fabric Composite Plates Subjected to Impact Loads

    Science.gov (United States)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Aitharaju, Venkat; Aashat, Satvir; Kia, Hamid

    2014-01-01

    Progressive failure analysis (PFA) of non-crimp fabric (NCF) composite laminates subjected to low velocity impact loads was performed using the COmplete STress Reduction (COSTR) damage model implemented through VUMAT and UMAT41 user subroutines in the frame works of the commercial finite element programs ABAQUS/Explicit and LS-DYNA, respectively. To validate the model, low velocity experiments were conducted and detailed correlations between the predictions and measurements for both intra-laminar and inter-laminar failures were made. The developed material and damage model predicts the peak impact load and duration very close with the experimental results. Also, the simulation results of delamination damage between the ply interfaces, in-plane matrix damages and fiber damages were all in good agreement with the measurements from the non-destructive evaluation data.

  6. Lifetime and residual strength of wood subjected to static and variable load

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1997-01-01

    The DVM-theory (Damaged Viscoelastic Material) previously developed by the author to predict lifetime of wood subjected to static loads is further developed in this paper such that harmonic load variations can also be considered. Lifetime (real time or number of cycles) is predicted as a function...... is successfully compared with data from experiments representing different wood products. Master graphs are developed which can be used in fatigue design of wood products in general. These graphs are valid for any creep behavior (relaxation, moisture content) and materials quality (grading, strength level.......It is strongly emphasised throughout the paper that reliable mechanical durability studies on wood cannot be made if the influence of wood rheology is disregarded. Lifetime predicted by Palmgren-Miner methods may cause considerably overestimated time to failure, especially at low frequencies. Results from...

  7. Relationship between Respiratory Load Perception and Perception of Nonrespiratory Sensory Modalities in Subjects with Life-Threatening Asthma

    Directory of Open Access Journals (Sweden)

    Kathleen L. Davenport

    2012-01-01

    Full Text Available Subjects with life-threatening asthma (LTA have reported decreased sensitivity to inspiratory resistive (R loads. It is unknown if decreased sensitivity is specific for inspiratory R loads, other types of respiratory loads, or a general deficit affecting sensory modalities. This study hypothesized that impairment is specific to respiratory stimuli. This study tested perceptual sensitivity of LTA, asthmatic (A, and nonasthmatic (NA subjects to 4 sensory modalities: respiratory, somatosensory, auditory, visual. Perceptual sensitivity was measured with magnitude estimation (ME: respiratory loads ME, determined using inspiratory R and pressure threshold (PT loads; somatosensory ME, determined using weight ranges of 2–20 kg; auditory ME, determined using graded magnitudes of 1 kHz tones delivered for 3 seconds bilaterally; visual ME, determined using gray-to-white disk intensity gradations on black background. ME for inspiratory R loads lessened for LTA over A and NA subjects. There was no significant difference between the 3 groups in ME for PT inspiratory loads, weight, sound, and visual trials. These results demonstrate that LTA subjects are poor perceivers of inspiratory R loads. This deficit in respiratory perception is specific to inspiratory R loads and is not due to perceptual deficits in other types of inspiratory loads, somatosensory, auditory, or visual sensory modalities.

  8. A structural analysis of an ocean going patrol boat subjected to planning loads

    Science.gov (United States)

    Clark, James H.; Lafreniere, Robert; Stoodt, Robert; Wiedenheft, John

    1987-01-01

    A static structural analysis of an ocean going patrol vessel subjected to hydrodynamic planning loads is discussed. The analysis required the development of a detailed model that included hull plating, five structural bulkheads, longitudinal and transverse stiffners, and a coarse representation of the superstructure. The finite element model was developed from fabrication drawings using the Navy computer aided design system. Various stress and displacement contours are shown for the entire hull. Because several critical areas appeared to be overstressed, these areas were remeshed for detail and are presented for completeness.

  9. Buckling And Postbuckling Of An Imperfect Plate Subjected To The Shear Load

    Directory of Open Access Journals (Sweden)

    Psotný Martin

    2015-12-01

    Full Text Available The stability analysis of an imperfect plate subjected to the shear load is presented. To solve this problem, a specialized computer program based on FEM has been created. The nonlinear finite element method equations are derived from the variational principle of minimum of total potential energy. To obtain the nonlinear equilibrium paths, the Newton-Raphson iteration algorithm is used. Corresponding levels of the total potential energy are defined. Special attention is paid to the influence of imperfections on the post-critical buckling mode. Obtained results are compared with those gained using ANSYS system.

  10. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (approx. 9 inches from the source) dominated by direct wave propagation, mid-field environment (approx. 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This report documents the outcome of the assessment.

  11. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading: Appendices

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O.; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (approx. 9 inches from the source) dominated by direct wave propagation, mid-field environment (approx. 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This document contains appendices to the Volume I report.

  12. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading. [Appendices

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O.; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (9 inches from the source) dominated by direct wave propagation, mid-field environment (approximately 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This document contains appendices to the Volume I report.

  13. Elasto-Plastic Behavior of Aluminum Foams Subjected to Compression Loading

    Science.gov (United States)

    Silva, H. M.; Carvalho, C. D.; Peixinho, N. R.

    2017-05-01

    The non-linear behavior of uniform-size cellular foams made of aluminum is investigated when subjected to compressive loads while comparing numerical results obtained in the Finite Element Method software (FEM) ANSYS workbench and ANSYS Mechanical APDL (ANSYS Parametric Design Language). The numerical model is built on AUTODESK INVENTOR, being imported into ANSYS and solved by the Newton-Raphson iterative method. The most similar conditions were used in ANSYS mechanical and ANSYS workbench, as possible. The obtained numerical results and the differences between the two programs are presented and discussed

  14. Accurate Finite Element Modelling of Chipboard Single-Stud Floor Panels subjected to Dynamic Loads

    DEFF Research Database (Denmark)

    Sjöström, A.; Flodén, O.; Persson, K.

    2012-01-01

    In multi-storey buildings, the use of lightweight material has many advantages. The low weight, the low energy consumption and the sustainability of the material are some attractive benefits from using lightweight materials. Compared with heavier structures i.e. concrete the challenge in construc......In multi-storey buildings, the use of lightweight material has many advantages. The low weight, the low energy consumption and the sustainability of the material are some attractive benefits from using lightweight materials. Compared with heavier structures i.e. concrete the challenge...... in lightweight buildings subjected to different types of loads....

  15. Properties and Behavior of Geopolymer Concrete Subjected to Explosive Air Blast Loading: A Review

    Directory of Open Access Journals (Sweden)

    Mohd Mortar Nurul Aida

    2017-01-01

    Full Text Available The severe damage to civilian buildings, public area, jet aircraft impact and defense target under explosive blast loading can cause a huge property loss. Most of researcher discusses the topics on design the concrete material model to sustain againts the explosive detonation. The implementation of modern reinforcement steels and fibres in ordinary Portland cement (OPC concrete matrix can reduce the extreme loading effects. However, most researchers have proved that geopolymer concrete (GPC has better mechanical properties towards high performance concrete, compared to OPC. GPC has the high early compressive strength and high ability to resist the thermal energy from explosive detonation. In addition, OPC production is less environmental friendly than geopolymer cement. Geopolymer used can lead to environmental protection besides being improved in mechanical properties. Thus, this paper highlighted on an experimental, numerical and the analytical studies cause of the explosive detonation impact to concrete structures.

  16. Validation of analysis methods for assessing flawed piping subjected to dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.; Wolterman, R.L.; Wilkowski, G.M. [Battelle, Columbus, OH (United States); Kot, C.A. [Argonne National Lab., IL (United States)

    1994-08-01

    Argonne National Laboratory and Battelle have jointly conducted a research program for the USNRC to evaluate the ability of current engineering analysis methods and one state-of-the-art analysis method to predict the behavior of circumferentially surface-cracked pipe system water-hammer experiment. The experimental data used in the evaluation were from the HDR Test Group E31 series conducted by the Kernforschungszentrum Karlsruhe (KfK) in Germany. The incentive for this evaluation was that simplified engineering methods, as well as newer ``state-of-the-art`` fracture analysis methods, have been typically validated only with static experimental data. Hence, these dynamic experiments were of high interest. High-rate dynamic loading can be classified as either repeating, e.g., seismic, or nonrepeating, e.g., water hammer. Development of experimental data and validation of cracked pipe analyses under seismic loading (repeating dynamic loads) are being pursued separately within the NRC`s International Piping Integrity Research Group (IPIRG) program. This report describes developmental and validation efforts to predict crack stability under water hammer loading, as well as comparisons using currently used analysis procedures. Current fracture analysis methods use the elastic stress analysis loads decoupled from the fracture mechanics analysis, while state-of-the-art methods employ nonlinear cracked-pipe time-history finite element analyses. The results showed that the current decoupled methods were conservative in their predictions, whereas the cracked pipe finite element analyses were more accurate, yet slightly conservative. The nonlinear time-history cracked-pipe finite element analyses conducted in this program were also attractive in that they were done on a small Apollo DN5500 workstation, whereas other cracked-pipe dynamic analyses conducted in Europe on the same experiments required the use of a CRAY2 supercomputer, and were less accurate.

  17. Computer science security research and human subjects: emerging considerations for research ethics boards.

    Science.gov (United States)

    Buchanan, Elizabeth; Aycock, John; Dexter, Scott; Dittrich, David; Hvizdak, Erin

    2011-06-01

    This paper explores the growing concerns with computer science research, and in particular, computer security research and its relationship with the committees that review human subjects research. It offers cases that review boards are likely to confront, and provides a context for appropriate consideration of such research, as issues of bots, clouds, and worms enter the discourse of human subjects review.

  18. Second-Order Nonlinear Analysis of Steel Tapered Beams Subjected to Span Loading

    Directory of Open Access Journals (Sweden)

    Ali Hadidi

    2014-03-01

    Full Text Available A second-order elastic analysis of tapered steel members with I-shaped sections subjected to span distributed and concentrated loadings is developed. Fixed end forces and moments as well as exact stiffness matrix of tapered Timoshenko-Euler beam are obtained with exact geometrical properties of sections. The simultaneous action of bending moment, shear, and axial force including P−δ effects is also considered in the analysis. A computer code has been developed in MATLAB software using a power series method to solve governing second-order differential equation of equilibrium with variable coefficients for beams with distributed span loading. A generalized matrix condensation technique is then utilized for analysis of beams with concentrated span loadings. The accuracy and efficiency of the results of the proposed method are verified through comparing them to those obtained from other approaches such as finite element methods, which indicates the robustness and time saving of this method even for large scale frames with tapered members.

  19. Analysis of Damage in Laminated Architectural Glazing Subjected to Wind Loading and Windborne Debris Impact

    Directory of Open Access Journals (Sweden)

    Daniel S. Stutts

    2013-05-01

    Full Text Available Wind loading and windborne debris (missile impact are the two primary mechanisms that result in window glazing damage during hurricanes. Wind-borne debris is categorized into two types: small hard missiles; such as roof gravel; and large soft missiles representing lumber from wood-framed buildings. Laminated architectural glazing (LAG may be used in buildings where impact resistance is needed. The glass plies in LAG undergo internal damage before total failure. The bulk of the published work on this topic either deals with the stress and dynamic analyses of undamaged LAG or the total failure of LAG. The pre-failure damage response of LAG due to the combination of wind loading and windborne debris impact is studied. A continuum damage mechanics (CDM based constitutive model is developed and implemented via an axisymmetric finite element code to study the failure and damage behavior of laminated architectural glazing subjected to combined loading of wind and windborne debris impact. The effect of geometric and material properties on the damage pattern is studied parametrically.

  20. Modeling of the stress-strain relationship for specimens made of S355J0 steel subjected to bending block loading with mean load

    Directory of Open Access Journals (Sweden)

    R. Pawliczek

    2017-10-01

    Full Text Available The paper presents results of calculation for modelling of the stressstrain relationship in the case of block loads with mean load value. A model, based on the stable hysteresis loops, was assumed and modified to use for block loading analysis. For stress history calculation, the proposed model and two other constitutive models were used. Results of fatigue test of specimens made of S355J0 steel subjected to bending block loading with mean load value are presented and used to verify the proposed model. In the tests, the mean load was increased and decreased in subsequent blocks. The changes of strain recorded during the tests shown in the paper indicate a different behavior of the material. Damage accumulation degree for block sequence was used to compare the results of calculations. It was shown, that stress history parameters (stress amplitude and mean stress value in this case are similar for all investigated models

  1. Structural Performance of a Hybrid FRP-Aluminum Modular Triangular Truss System Subjected to Various Loading Conditions

    Directory of Open Access Journals (Sweden)

    Dongdong Zhang

    2014-01-01

    Full Text Available A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1 the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2 under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3 the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors.

  2. Behaviour of the buccal crestal bone levels after immediate placement of implants subjected to immediate loading.

    Science.gov (United States)

    Lemes, H deP; Sartori, I A deM; Cardoso, L C; Ponzoni, D

    2015-03-01

    The aim of this study was to measure changes in buccal alveolar crestal bone levels after immediate placement and loading of dental implants with Morse taper prosthetic abutments after tooth extraction. This study followed the STROBE guidelines regarding prospective cohort studies. The sample comprised 12 patients with a mean age of 45 years, in whom a central or upper lateral incisor was indicated for extraction. Prior to extraction, computed tomography (CT) analysis was carried out to assess the presence of the buccal bone crest. CT scans were performed at 24 h and at 6 months after immediate implant placement and immediate loading. The distance from the most apical point of the implant platform to the buccal bone crest was assessed at the two time points. The buccal bone crest height was evaluated at three points in the mesio-distal direction: (1) the centre point of the alveolus, (2) 1mm mesial to the centre point, and (3) 1 mm distal to the centre point. The values obtained were subjected to statistical analysis, comparing the distances from the bone crest to the implant platform for the two time points. After 6 months there was a statistically significant, non-uniform reduction in height at the level of the crest of the buccal bone in the cervical direction. It is concluded that the buccal bone crest of the immediate implants that replaced the maxillary incisors underwent apical resorption when subjected to immediate loading. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. Differential effects of cognitive load on subjective versus motor responses to ambiguously valenced facial expressions.

    Science.gov (United States)

    Mattek, Alison M; Whalen, Paul J; Berkowitz, Julia L; Freeman, Jonathan B

    2016-09-01

    Valence is a principal dimension by which we understand emotional experiences, but oftentimes events are not easily classified as strictly positive or negative. Inevitably, individuals vary in how they tend to interpret the valence of ambiguous situations. Surprised facial expressions are one example of a well-defined, ambiguous affective event that induces trait-like differences in the propensity to form a positive or negative interpretation. To investigate the nature of this affective bias, we asked participants to organize emotional facial expressions (surprised, happy, sad) into positive/negative categories while recording their hand-movement trajectories en route to each response choice. We found that positivity-negativity bias resulted in differential hand movements for modal versus nonmodal response trajectories, such that when an individual categorized a surprised face according to his or her nonmodal interpretation (e.g., a negatively biased individual selecting a positive interpretation), the hand showed an enhanced spatial attraction to the alternative, modal response option (e.g., negative) in the opposite corner of the computer screen (Experiment 1). Critically, we also demonstrate that this asymmetry between modal versus nonmodal response trajectories is mitigated when the valence interpretations are made under a cognitive load, although the frequency of modal interpretations is unaffected by the load (Experiment 2). These data inform a body of seemingly disparate findings regarding the effect of cognitive effort on affective responses, by showing within a single paradigm that varying cognitive load selectively alters the dynamic motor movements involved in indicating affective interpretations, whereas the subjective interpretations themselves remain consistent across variable cognitive loads. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Numerical and Theoretical Analysis of Plastic Response of 5A06 Aluminum Circular Plates Subjected to Underwater Explosion Loading

    Science.gov (United States)

    Ren, Peng; Zhang, Wei

    2013-06-01

    Dynamic response analysis of structures subjected to underwater explosion loading has been always an interesting field for researchers. Understanding the deformation and failure mechanism of simple structures plays an important role in an actual project under this kind of loading. In this paper, the deformation and failure characteristics of 5A06 aluminum circular plates were investigated computationally and theoretically. The computational study was based on a Johnson-cook material parameter mode which was obtained from several previous studies provides a good description of deformation and failure of 5A06 aluminum circular plates under underwater explosion loading. The deformation history of the clamped circular plate is recorded; the maximum deflection and the thickness reduction measurements of target plates at different radii were conducted. The computational approach provided insight into the relationship between the failure mechanism and the strength of impact wave, and a computing formulae for strain field of the specimen was derived based on the same volume principle and rigid-plastic assumption. The simulation and theoretical calculation results are in good agreement with the experiments results. National Natural Science Foundation of China (NO:11272057).

  5. Single Subject Research: A Synthesis of Analytic Methods

    Science.gov (United States)

    Alresheed, Fahad; Hott, Brittany L.; Bano, Carmen

    2013-01-01

    Historically, the synthesis of single subject design has employed visual inspection to yield significance of results. However, current research is supporting different techniques that will facilitate the interpretation of these intervention outcomes. These methods can provide more reliable data than employing visual inspection in isolation. This…

  6. Current Research in Bookkeeping/Accounting and Basic Business Subjects

    Science.gov (United States)

    Nanassy, Louis C., Comp.

    1976-01-01

    Listed are 26 doctoral and masters theses completed during the years 1974-5 involving research in bookkeeping/accounting and basic business subjects. The entries are arranged alphabetically by author and include the title of the study and the name of the associated institution. (MS)

  7. Strain Rate Dependent Deformation of a Polymer Matrix Composite with Different Microstructures Subjected to Off-Axis Loading

    National Research Council Canada - National Science Library

    Zhu, Xiaojun; Chen, Xuefeng; Zhai, Zhi; Yang, Zhibo; Li, Xiang; He, Zhengjia

    2014-01-01

    ... are often subjected to complex loadings under extreme circumstances [3, 4] in which the properties of the PMCs exhibit highly nonlinear and rate dependence, so it is necessary for structural design and an...

  8. Measuring Cognitive Load during Simulation-Based Psychomotor Skills Training: Sensitivity of Secondary-Task Performance and Subjective Ratings

    Science.gov (United States)

    Haji, Faizal A.; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-01-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance…

  9. Large scale centrifuge test of a geomembrane-lined landfill subject to waste settlement and seismic loading.

    Science.gov (United States)

    Kavazanjian, Edward; Gutierrez, Angel

    2017-10-01

    A large scale centrifuge test of a geomembrane-lined landfill subject to waste settlement and seismic loading was conducted to help validate a numerical model for performance based design of geomembrane liner systems. The test was conducted using the 240g-ton centrifuge at the University of California at Davis under the U.S. National Science Foundation Network for Earthquake Engineering Simulation Research (NEESR) program. A 0.05mm thin film membrane was used to model the liner. The waste was modeled using a peat-sand mixture. The side slope membrane was underlain by lubricated low density polyethylene to maximize the difference between the interface shear strength on the top and bottom of the geomembrane and the induced tension in it. Instrumentation included thin film strain gages to monitor geomembrane strains and accelerometers to monitor seismic excitation. The model was subjected to an input design motion intended to simulate strong ground motion from the 1994 Hyogo-ken Nanbu earthquake. Results indicate that downdrag waste settlement and seismic loading together, and possibly each phenomenon individually, can induce potentially damaging tensile strains in geomembrane liners. The data collected from this test is publically available and can be used to validate numerical models for the performance of geomembrane liner systems. Published by Elsevier Ltd.

  10. Human subjects protection issues in QUERI implementation research: QUERI Series

    Directory of Open Access Journals (Sweden)

    Ritchie Mona

    2008-02-01

    Full Text Available Abstract Background Human Subjects protections approaches, specifically those relating to research review board oversight, vary throughout the world. While all are designed to protect participants involved in research, the structure and specifics of these institutional review boards (IRBs can and do differ. This variation affects all types of research, particularly implementation research. Methods In 2001, we began a series of inter-related studies on implementing evidence-based collaborative care for depression in Veterans Health Administration primary care. We have submitted more than 100 IRB applications, amendments, and renewals, and in doing so, we have interacted with 13 VA and University IRBs across the United States (U.S.. We present four overarching IRB-related themes encountered throughout the implementation of our projects, and within each theme, identify key challenges and suggest approaches that have proved useful. Where applicable, we showcase process aids developed to assist in resolving a particular IRB challenge. Results There are issues unique to implementation research, as this type of research may not fit within the traditional Human Subjects paradigm used to assess clinical trials. Risks in implementation research are generally related to breaches of confidentiality, rather than health risks associated with traditional clinical trials. The implementation-specific challenges discussed are: external validity considerations, Plan-Do-Study-Act cycles, risk-benefit issues, the multiple roles of researchers and subjects, and system-level unit of analysis. Discussion Specific aspects of implementation research interact with variations in knowledge, procedures, and regulatory interpretations across IRBs to affect the implementation and study of best methods to increase evidence-based practice. Through lack of unambiguous guidelines and local liability concerns, IRBs are often at risk of applying both variable and inappropriate or

  11. Methods to model particulate matter clarification of unit operations subject to unsteady loadings.

    Science.gov (United States)

    Spelman, David; Sansalone, John J

    2017-05-15

    Stormwater, and also wastewater unit operations (UOs) to a much lower extent, are subject to unsteady hydrodynamic and particulate matter (PM) fluxes. Simulating fully transient clarification of hetero-disperse PM requires much greater computational expense compared to steady simulations. An alternative to fully unsteady methods are stepwise steady (SS) methods which use stepwise steady flow transport and fate to approximate unsteady PM clarification of a UO during transient hydraulic loadings such as rainfall-runoff. The rationale is reduced computational effort for computational fluid dynamics (CFD) compared to simulating continuous unsteadiness of such events. An implicit solution stepwise steady (IS3) method is one approach which builds upon previous SS methods. The IS3 method computes steady flows that are representative of unsteady PM transport throughout an unsteady loading. This method departs from some previous SS methods that assume PM fate can be simulated with an instantaneous clarifier (basin) influent flowrate coupled with a PM input. In this study, various SS methods were tested for basins of varying size and residence time to examine PM fate. Differences between SS methods were a function of turnover fraction indicating the role of unsteady flowrates on PM transport for larger basins of longer residence times. The breakpoint turnover fraction was between two and three. The IS3 method best approximated unsteady behavior of larger basins. These methods identified limitations when utilizing standard event-based loading analysis for larger basins. For basins with a turnover fraction less than two, the majority of effluent PM did not originate from the event-based flow; originating from previous event loadings or existing storage. Inter- and multiple event processes and interactions, that are dependent on this inflow turnover fraction, are not accounted for by single event-based inflow models. Results suggest the use of long-term continuous modeling

  12. The response of endocrine system to stress loads during space flight in human subject

    Science.gov (United States)

    Macho, L.; Koška, J.; Kšinantová, L.; Pacak, K.; Hoff, T.; Noskov, V. B.; Grigoriev, A. I.; Vigaš, M.; Kvetňanský, R.

    The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transforred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.

  13. Plastic damage induced fracture behaviors of dental ceramic layer structures subjected to monotonic load.

    Science.gov (United States)

    Wang, Raorao; Lu, Chenglin; Arola, Dwayne; Zhang, Dongsheng

    2013-08-01

    The aim of this study was to compare failure modes and fracture strength of ceramic structures using a combination of experimental and numerical methods. Twelve specimens with flat layer structures were fabricated from two types of ceramic systems (IPS e.max ceram/e.max press-CP and Vita VM9/Lava zirconia-VZ) and subjected to monotonic load to fracture with a tungsten carbide sphere. Digital image correlation (DIC) and fractography technology were used to analyze fracture behaviors of specimens. Numerical simulation was also applied to analyze the stress distribution in these two types of dental ceramics. Quasi-plastic damage occurred beneath the indenter in porcelain in all cases. In general, the fracture strength of VZ specimens was greater than that of CP specimens. The crack initiation loads of VZ and CP were determined as 958 ± 50 N and 724 ± 36 N, respectively. Cracks were induced by plastic damage and were subsequently driven by tensile stress at the elastic/plastic boundary and extended downward toward to the veneer/core interface from the observation of DIC at the specimen surface. Cracks penetrated into e.max press core, which led to a serious bulk fracture in CP crowns, while in VZ specimens, cracks were deflected and extended along the porcelain/zirconia core interface without penetration into the zirconia core. The rupture loads for VZ and CP ceramics were determined as 1150 ± 170 N and 857 ± 66 N, respectively. Quasi-plastic deformation (damage) is responsible for crack initiation within porcelain in both types of crowns. Due to the intrinsic mechanical properties, the fracture behaviors of these two types of ceramics are different. The zirconia core with high strength and high elastic modulus has better resistance to fracture than the e.max core. © 2013 by the American College of Prosthodontists.

  14. Effect of Piezoelectric Implant on the Structural Integrity of Composite Laminates Subjected to Tensile Loads

    Science.gov (United States)

    Masmoudi, Sahir; El Mahi, Abderrahim; Turki, Saïd

    2017-02-01

    The embedment of sensors within composite structures gives the opportunity to develop smart materials for health and usage monitoring systems. This study investigates the use of acoustic emission monitoring with embedded piezoelectric sensor during mechanical tests in order to identify the effects of introducing the sensor into the composite materials. The composite specimen with and without embedded sensor were subject to tensile static and fatigue loading. The analysis and observation of AE signals show that the integration of a sensor presents advantage of the detection of the acoustic events and also show the presence of three or four types of damage during tests. The incorporation of piezoelectric sensor has a negligible influence on the mechanical properties of materials.

  15. Nonlinear Analysis and Scaling Laws for Noncircular Composite Structures Subjected to Combined Loads

    Science.gov (United States)

    Hilburger, Mark W.; Rose, Cheryl A.; Starnes, James H., Jr.

    2001-01-01

    Results from an analytical study of the response of a built-up, multi-cell noncircular composite structure subjected to combined internal pressure and mechanical loads are presented. Nondimensional parameters and scaling laws based on a first-order shear-deformation plate theory are derived for this noncircular composite structure. The scaling laws are used to design sub-scale structural models for predicting the structural response of a full-scale structure representative of a portion of a blended-wing-body transport aircraft. Because of the complexity of the full-scale structure, some of the similitude conditions are relaxed for the sub-scale structural models. Results from a systematic parametric study are used to determine the effects of relaxing selected similitude conditions on the sensitivity of the effectiveness of using the sub-scale structural model response characteristics for predicting the full-scale structure response characteristics.

  16. Topology optimization for elastic base under rectangular plate subjected to moving load

    Directory of Open Access Journals (Sweden)

    Jilavyan Samvel H.

    2015-09-01

    Full Text Available Distribution optimization of elastic material under elastic isotropic rectangular thin plate subjected to concentrated moving load is investigated in the present paper. The aim of optimization is to damp its vibrations in finite (fixed time. Accepting Kirchhoff hypothesis with respect to the plate and Winkler hypothesis with respect to the base, the mathematical model of the problem is constructed as two-dimensional bilinear equation, i.e. linear in state and control function. The maximal quantity of the base material is taken as optimality criterion to be minimized. The Fourier distributional transform and the Bubnov-Galerkin procedures are used to reduce the problem to integral equality type constraints. The explicit solution in terms of two- dimensional Heaviside‘s function is obtained, describing piecewise-continuous distribution of the material. The determination of the switching points is reduced to a problem of nonlinear programming. Data from numerical analysis are presented.

  17. Effects of unilateral robotic limb loading on gait characteristics in subjects with chronic stroke

    Directory of Open Access Journals (Sweden)

    Krebs Hermano I

    2010-05-01

    Full Text Available Abstract Background Hemiparesis after stroke often leads to impaired ankle motor control that impacts gait function. In recent studies, robotic devices have been developed to address this impairment. While capable of imparting forces to assist during training and gait, these devices add mass to the paretic leg which might encumber patients' gait pattern. The purpose of this study was to assess the effects of the added mass of one of these robots, the MIT's Anklebot, while unpowered, on gait of chronic stroke survivors during overground and treadmill walking. Methods Nine chronic stroke survivors walked overground and on a treadmill with and without the anklebot mounted on the paretic leg. Gait parameters, interlimb symmetry, and joint kinematics were collected for the four conditions. Repeated-measures analysis of variance (ANOVA tests were conducted to examine for possible differences across four conditions for the paretic and nonparetic leg. Results The added inertia and friction of the unpowered anklebot had no statistically significant effect on spatio-temporal parameters of gait, including paretic and nonparetic step time and stance percentage, in both overground and treadmill conditions. Noteworthy, interlimb symmetry as characterized by relative stance duration was greater on the treadmill than overground regardless of loading conditions. The presence of the unpowered robot loading reduced the nonparetic knee peak flexion on the treadmill and paretic peak dorsiflexion overground (p Conclusions Our results suggest that for these subjects the added inertia and friction of this backdriveable robot did not significantly alter their gait pattern.

  18. Telomere Length, Proviral Load and Neurologic Impairment in HTLV-1 and HTLV-2-Infected Subjects

    Directory of Open Access Journals (Sweden)

    Benjamin Usadi

    2016-08-01

    Full Text Available Short or damaged telomeres have been implicated in degenerative conditions. We hypothesized that analysis of telomere length (TL in human T-cell lymphotropic virus (HTLV infection and HTLV-associated neuropathy might provide clues to the etiology of HTLV-associated disease and viral dynamics. A subset of 45 human T-cell lymphotropic virus type 1 (HTLV-1, 45 human T-cell lymphotropic virus type 2 (HTLV-2, and 45 seronegative subjects was selected from the larger HTLV Outcomes Study (HOST cohort, matched on age, sex and race/ethnicity. Telomere-to-single-copy gene (T/S ratio (a measure of TL and HTLV-1 and HTLV-2 proviral loads were measured in peripheral blood mononuclear cells (PBMCs using quantitative PCR (qPCR. Vibration sensation measured by tuning fork during neurologic examinations performed as part of the HOST study allowed for an assessment of peripheral neuropathy. TL was compared between groups using t-tests, linear and logistic regression. Mean T/S ratio was 1.02 ± 0.16 in HTLV-1, 1.03 ± 0.17 in HTLV-2 and 0.99 ± 0.18 in HTLV seronegative subjects (p = 0.322. TL was not associated with HTLV-1 or -2 proviral load. Shorter TL was significantly associated with impaired vibration sense in the HTLV-2 positive group only. Overall, we found no evidence that telomere length was affected by chronic HTLV-1 and HTLV-2 infection. That TL was only associated with peripheral neuropathy in the HTLV-2-positive group is intriguing, but should be interpreted cautiously. Studies with larger sample size and telomere length measurement in lymphocyte subsets may clarify the relationship between TL and HTLV-infection.

  19. Who is the research subject in cluster randomized trials in health research?

    Directory of Open Access Journals (Sweden)

    Brehaut Jamie C

    2011-07-01

    Full Text Available Abstract This article is part of a series of papers examining ethical issues in cluster randomized trials (CRTs in health research. In the introductory paper in this series, we set out six areas of inquiry that must be addressed if the CRT is to be set on a firm ethical foundation. This paper addresses the first of the questions posed, namely, who is the research subject in a CRT in health research? The identification of human research subjects is logically prior to the application of protections as set out in research ethics and regulation. Aspects of CRT design, including the fact that in a single study the units of randomization, experimentation, and observation may differ, complicate the identification of human research subjects. But the proper identification of human research subjects is important if they are to be protected from harm and exploitation, and if research ethics committees are to review CRTs efficiently. We examine the research ethics literature and international regulations to identify the core features of human research subjects, and then unify these features under a single, comprehensive definition of human research subject. We define a human research subject as any person whose interests may be compromised as a result of interventions in a research study. Individuals are only human research subjects in CRTs if: (1 they are directly intervened upon by investigators; (2 they interact with investigators; (3 they are deliberately intervened upon via a manipulation of their environment that may compromise their interests; or (4 their identifiable private information is used to generate data. Individuals who are indirectly affected by CRT study interventions, including patients of healthcare providers participating in knowledge translation CRTs, are not human research subjects unless at least one of these conditions is met.

  20. Residual stress redistribution in shot peened samples subject to mechanical loading

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, Dennis J., E-mail: dennis.buchanan@udri.udayton.edu [University of Dayton Research Institute, 300 College Park, Dayton, OH 45469-0020 (United States); John, Reji [Materials and Manufacturing Directorate, Air Force Research Laboratory (AFRL/RXCM), Wright-Patterson Air Force Base, OH 45433-7817 (United States)

    2014-10-06

    Shot peening is a well-established surface treatment process that imparts large compressive residual stresses onto the surface and at shallow depths to retard initiation and growth of fatigue cracks. The plastic deformation developed during the surface treatment sets up a constraint that retains compressive stresses on the surface balanced by tensile residual stresses in the interior. However, component service histories that produce subsequent plastic deformation may redistribute these residual stresses. In most engineering components, this additional plastic deformation is localized to stress concentration sites such as holes, notches, and fillets. In the case of gross plastic deformation where the entire cross section experiences material yielding the residual stress profile may redistribute, resulting in tensile stresses on the outside surface balanced by compression in the interior. This paper describes a series of experiments combined with models to explain the redistribution in residual stress depth profiles subject to applied stresses producing gross plastic strains in shot peened laboratory specimens. The initial room temperature residual stress and plastic strain profiles provide initial conditions for predictions. Model predictions correlate well with experimental results on shot peened dogbone specimens subject to single cycle and fatigue loading conditions at elevated temperature. Experiments on shot peened notched specimens do not exhibit the same stress redistribution even for larger applied stresses.

  1. Biomechanical analysis of running in weightlessness on a treadmill equipped with a subject loading system.

    Science.gov (United States)

    Gosseye, Thierry P; Willems, Patrick A; Heglund, Norman C

    2010-11-01

    One countermeasure used during long-duration spaceflight to maintain bone and muscle mass is a treadmill equipped with a subject loading system (SLS) that simulates gravity. To date, little is known about the biomechanics of running in weightlessness on such a treadmill-SLS system. We have designed an instrumented treadmill/force plate to compare the biomechanics of running in weightlessness to running on Earth. Gravity was simulated by two pneumatic pistons pulling downward on a subject's harness, with a force approximately equal to body weight on Earth. Four transducers, mounted under the treadmill, measured the three components of the reaction force exerted by the tread belt under the foot. A high-speed video camera recorded the movements of limb segments while the electromyography of the four lower limb muscles was registered. Experiments in weightlessness were conducted during the European Space Agency parabolic flight campaigns. Control experiments were performed on the same subjects on Earth. When running on the treadmill with an SLS, the bouncing mechanism of running is preserved. Depending on the speed of progression, the ground reaction forces, contact and aerial times, muscular work and bone stress differed by a maximum of ± 5-15% during running on the treadmill with an SLS, as compared to that on Earth. The movements of the lower limb segments and the EMG patterns of the lower limb muscles were also comparable. Thus, the biomechanics of running on Earth can reasonably be duplicated in weightlessness using a treadmill with an SLS that generates a pull-down force close to body weight on Earth.

  2. Older adults’ attitudes toward noncompetent subjects participating in Alzheimers research

    Science.gov (United States)

    Karlawish, Jason; Rubright, Jonathan; Casarett, David; Cary, Mark; TenHave, Thomas; Sankar, Pamela

    2008-01-01

    Objective Since research that enrolls noncompetent patients with Alzheimers disease and does not present potential benefit to subjects is the source of substantial ethical controversy, we assessed willingness to have a proxy for research decision making, and, for each of two Alzheimers disease biomarker studies (minimal risk blood draw and a greater than minimal risk blood draw and lumbar puncture), willingness to grant an advance consent, and willingness to grant a proxy leeway over advance consent. Methods Face to face survey of 538 persons 65 and over who resided in the Southeastern Pennsylvania region Results The majority 83% (445/538) granted advance consent to a blood draw study and nearly half to a blood draw plus lumbar puncture 259 (48%). Most persons (96%) were willing to identify a proxy for research decision making and most were willing to grant their proxy leeway over their advance consent: blood draw 434 (81%), and 375 (70%) blood draw plus lumbar puncture. Combining the preferences for advance consent and leeway, the proportion who would permit being enrolled in the blood draw and spinal fluid sample studies were, respectively, 92% (497/538) and 75% (404/538). Multi-variate models showed that willingness to be enrolled in research was most strongly associated with a favorable attitude about biomedical research. Conclusions Older adults generally support enrolling noncompetent persons with Alzheimers disease into research that does not present a benefit to subjects. Willingness to grant their proxy leeway over advance consent and a favorable attitude about biomedical research substantially explain this willingness. PMID:18923066

  3. Application of shearography to crack detection in concrete structures subjected to traffic loading

    Science.gov (United States)

    Muzet, V.; Blain, P.; Przybyla, D.

    2010-09-01

    Early detection of defects in concrete structures, such as bridges or dams, is essential to optimize the maintenance of civil engineering facilities. Optical methods constitute non-destructive means of control and measurement but they are generally confined in laboratories where both the setup and environnement are controlled. The method of shearography is especially well adapted to detect damages due to both its capacity to distinctly visualize strain concentration zones and its robustness. The experimental set-up is relatively compact, which enables to examine an extensive surface area by simply moving the shearographic head. In this paper, the application of this methodology for the detection of cracks is presented on concrete samples and circulated outside concrete structures. Due to its sensitivity to strain concentration, shearography is able to detect structural cracks, even when they were not through-cracks. Operational implementation is made on two circulated structures with experts in manual cracks detection. No stimulation device is used. In the first structure, cracks are detected on the bridge deck and on the bridge abutment. In the second structure, cracks on the intrados of the bridge deck are detected and also beginning of cracks which have not been detected by the visual inspection. Different areas are scanned and the results are in agreement with the visual inspection. This technique enables detecting cracks on structures subjected to traffic load. The natural loading of an engineering structure, i.e. the rolling traffic it bears, proves well suited for cracks detection by means of shearography, provided traffic patterns are regular enough.

  4. Measuring cognitive load during simulation-based psychomotor skills training: sensitivity of secondary-task performance and subjective ratings.

    Science.gov (United States)

    Haji, Faizal A; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-12-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p = 0.012; SDR 0.27 vs. 0.97, p instructional design research are discussed.

  5. Device Design and Test of Fatigue Behaviour of Expansion Anchor Subjected to Tensile Loads

    Directory of Open Access Journals (Sweden)

    Zhang Jinfeng

    2016-01-01

    Full Text Available In order to study on the fatigue behaviour of expansion anchor (M16, grade 8.8 for overhead contact system in electrification railways, a set of safe, practical loading device is designed and a fatigue test campaign was carried out at structural laboratory of China Academy of Building Research on expansion anchor embedded in concrete block. The mobile frame of the loading device was designed well by finite-element simulation. According to some fatigue performance test of expansion anchor with different size and form, the device have been assessed experimentally its dependability. The results were found that no fatigue damage phenomenon occurred in all specimens after 2×106 cycles tensile fatigue test in this specific series. It shows that in the condition of medium level or slightly lower maximum stress limit and nominal stress range, expansion bolt has good fatigue resistance. The biggest relative displacement and the residual relative displacement after test (Δδ = δ2-δ1 was also strongly lower than the symbol of the fatigue test failure index of this specific series (0.5mm in the high cycle fatigue regime. The ultimate tension failures mode after fatigue tests in all tested samples take place in the concrete anchorage zone. The reduction range of the ultimate tensile strength properties of the anchorage system was not obvious, and the concrete was seen to be the weakest link of the system.

  6. Centrifuge modelling of large diameter pile in sand subject to lateral loading

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    regulations are developed for long flexible piles with diameters up to approximately 2.0 m and are based on a very limited number of tests. Hence, the method has not been validated for rigid piles with diameters of 4 to 6 m. The primary issues concerning the validity of the standard p-y curves for large...... diameter rigid piles are:  The initial stiffness of the curves and description of the static behaviour, including ultimate bearing capacity.  The behaviour with respect to cyclic loading both stiffness degradation and ultimate bearing capacity. The aim of the present research is to investigate the static...... and cyclic behaviour of large diameter rigid piles in dry sand by use of physical modelling. The physical modelling has been carried out at Department of Civil Engineering at the Danish Technical University (DTU.BYG), in the period from 2005 to 2009. The main centrifuge facilities, and especially...

  7. Reliability Assessment of Long Span Suspension Bridges Subjected to Dead Loads

    OpenAIRE

    Antonsen, Kristin

    2016-01-01

    In the present study the influence of standardized safety factors in large and heavy structures, where the major loading arises from self-weight of the structure itself, is considered. For this purpose, a reliability analysis of the Hardanger Bridge is performed. The loading is assumed to originate from the self-weight of the bridge deck, hangers and main cables only, i.e. all other loads are neglected. The reliability analysis is performed by comparing axial loading and resistance capaci...

  8. Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games.

    Science.gov (United States)

    Iturricastillo, Aitor; Granados, Cristina; Los Arcos, Asier; Yanci, Javier

    2017-04-01

    The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards' training load and Stagno's training impulses (TRIMP MOD ) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards' training load and TRIMP MOD ), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.

  9. Structural response of full-scale concrete bridges subjected to high load magnitudes

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Schmidt, Jacob Wittrup; Jensen, Thomas Westergaard

    efficiently could be used for in-situ measurements. The load was applied semi-deformation controlled by a combination of dead load and hydraulic jacks. The novel high magnitude loading-rig worked well. It was also possible to achieve good readings from the monitoring equipment in combination with the applied...

  10. The Applied Behavior Analysis Research Paradigm and Single-Subject Designs in Adapted Physical Activity Research.

    Science.gov (United States)

    Haegele, Justin A; Hodge, Samuel Russell

    2015-10-01

    There are basic philosophical and paradigmatic assumptions that guide scholarly research endeavors, including the methods used and the types of questions asked. Through this article, kinesiology faculty and students with interests in adapted physical activity are encouraged to understand the basic assumptions of applied behavior analysis (ABA) methodology for conducting, analyzing, and presenting research of high quality in this paradigm. The purposes of this viewpoint paper are to present information fundamental to understanding the assumptions undergirding research methodology in ABA, describe key aspects of single-subject research designs, and discuss common research designs and data-analysis strategies used in single-subject studies.

  11. Finite Element Analysis of Aluminum Honeycombs Subjected to Dynamic Indentation and Compression Loads

    Directory of Open Access Journals (Sweden)

    A.S.M. Ayman Ashab

    2016-03-01

    Full Text Available The mechanical behavior of aluminum hexagonal honeycombs subjected to out-of-plane dynamic indentation and compression loads has been investigated numerically using ANSYS/LS-DYNA in this paper. The finite element (FE models have been verified by previous experimental results in terms of deformation pattern, stress-strain curve, and energy dissipation. The verified FE models have then been used in comprehensive numerical analysis of different aluminum honeycombs. Plateau stress, σpl, and dissipated energy (EI for indentation and EC for compression have been calculated at different strain rates ranging from 102 to 104 s−1. The effects of strain rate and t/l ratio on the plateau stress, dissipated energy, and tearing energy have been discussed. An empirical formula is proposed to describe the relationship between the tearing energy per unit fracture area, relative density, and strain rate for honeycombs. Moreover, it has been found that a generic formula can be used to describe the relationship between tearing energy per unit fracture area and relative density for both aluminum honeycombs and foams.

  12. ANALYSIS OF NON-CIRCULAR MEMBERS SUBJECTED TO TWISTING LOADS: A FINITE DIFFERENCE APPROACH

    Directory of Open Access Journals (Sweden)

    Chaitanya Goteti

    2015-09-01

    Full Text Available Abstract Many torque carrying members have circular sections such as shafts. However, there are certain structural members like automotive chassis frames, cross members and machine frames which are often subjected to twisting loads and their cross sections are non circular. several methods were developed to analyze such sections such as Saint Venant’s semi inverse method, Prandtl’s elastic membrane analogy...etc. In this paper, the second order partial differential stress function equation for non-circular torsional members is applied on a rectangular section for different b/h (height /width of section values and the solutions for maximum torsional shear stress are found by employing second order finite difference method. The results are compared to the results obtained from commercial finite element software (ANSYS 10 and by direct solution of the stress function equation using analytical correlations available for rectangular sections. The results obtained by different approaches are in close congruence with a percentage deviation of only 3.22. It is observed that, in implementing second order finite difference scheme, the error in estimating stress is proportional to S2. Where “S” is the grid size.   Keywords: Non-Circular Section, Prandtl’s stress function, Finite difference scheme, Grid size

  13. Finite element modeling of laminated composite plates with locally delaminated interface subjected to impact loading.

    Science.gov (United States)

    Abo Sabah, Saddam Hussein; Kueh, Ahmad Beng Hong

    2014-01-01

    This paper investigates the effects of localized interface progressive delamination on the behavior of two-layer laminated composite plates when subjected to low velocity impact loading for various fiber orientations. By means of finite element approach, the laminae stiffnesses are constructed independently from their interface, where a well-defined virtually zero-thickness interface element is discreetly adopted for delamination simulation. The present model has the advantage of simulating a localized interfacial condition at arbitrary locations, for various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. In comparison, the model shows good agreement with existing results from the literature when modeled in a perfectly bonded state. It is found that as the local delamination area increases, so does the magnitude of the maximum displacement history. Also, as top and bottom fiber orientations deviation increases, both central deflection and energy absorption increase although the relative maximum displacement correspondingly decreases when in contrast to the laminates perfectly bonded state.

  14. Finite Element Modeling of Laminated Composite Plates with Locally Delaminated Interface Subjected to Impact Loading

    Directory of Open Access Journals (Sweden)

    Saddam Hussein Abo Sabah

    2014-01-01

    Full Text Available This paper investigates the effects of localized interface progressive delamination on the behavior of two-layer laminated composite plates when subjected to low velocity impact loading for various fiber orientations. By means of finite element approach, the laminae stiffnesses are constructed independently from their interface, where a well-defined virtually zero-thickness interface element is discreetly adopted for delamination simulation. The present model has the advantage of simulating a localized interfacial condition at arbitrary locations, for various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. In comparison, the model shows good agreement with existing results from the literature when modeled in a perfectly bonded state. It is found that as the local delamination area increases, so does the magnitude of the maximum displacement history. Also, as top and bottom fiber orientations deviation increases, both central deflection and energy absorption increase although the relative maximum displacement correspondingly decreases when in contrast to the laminates perfectly bonded state.

  15. Finite Element Modeling of Laminated Composite Plates with Locally Delaminated Interface Subjected to Impact Loading

    Science.gov (United States)

    Abo Sabah, Saddam Hussein; Kueh, Ahmad Beng Hong

    2014-01-01

    This paper investigates the effects of localized interface progressive delamination on the behavior of two-layer laminated composite plates when subjected to low velocity impact loading for various fiber orientations. By means of finite element approach, the laminae stiffnesses are constructed independently from their interface, where a well-defined virtually zero-thickness interface element is discreetly adopted for delamination simulation. The present model has the advantage of simulating a localized interfacial condition at arbitrary locations, for various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. In comparison, the model shows good agreement with existing results from the literature when modeled in a perfectly bonded state. It is found that as the local delamination area increases, so does the magnitude of the maximum displacement history. Also, as top and bottom fiber orientations deviation increases, both central deflection and energy absorption increase although the relative maximum displacement correspondingly decreases when in contrast to the laminates perfectly bonded state. PMID:24696668

  16. Femoral neck structure in adult female athletes subjected to different loading modalities.

    Science.gov (United States)

    Nikander, Riku; Sievänen, Harri; Heinonen, Ari; Kannus, Pekka

    2005-03-01

    Loading modality is a strong external determinant of structure and concomitant strength of the femoral neck. Particularly effective seem to be loadings, which arise from high impacts or impacts from atypical loading directions. Physical loading plays an important role, not only in the process of bone modeling and remodeling, but also in shaping a mechanically appropriate bone structure. This study aimed at testing the hypothesis that the type of loading partly determines the femoral neck structure. A total of 255 premenopausal female athletes representing volleyball, hurdling, squash-playing, soccer, speed skating, step aerobics, weight-lifting, orienteering, cross-country skiing, cycling, and swimming and their 30 nonathletic counterparts were measured with DXA. Besides the conventional areal BMD (aBMD) of the femoral neck, the hip structure analysis (HSA) was used to estimate the cross-sectional area (CSA), subperiosteal width (W), and section modulus (Z, an index of bone strength) at the narrowest section of the femoral neck. Also, training history, muscle strength, and calcium intake were assessed. The above-mentioned sports were classified according to the type of loading they apparently produce at the hip region; that is, high-impact loading (volleyball, hurdling), odd-impact loading (squash-playing, soccer, speed-skating, step aerobics), high-magnitude loading (weightlifting), low-impact loading (orienteering, cross-country skiing), and nonimpact loading (swimming, cycling). High-impact and odd-impact loading sports were associated with the highest age-, weight-, and height-adjusted aBMD (23% and 29% higher values compared to nonathletic referents), CSA (22% and 27%), and Z (22% and 26%). In contrast, repetitive, nonimpact loading sports were not associated with any clear benefit in any bone value compared with the referents. The W at the narrowest femoral neck section was similar in all groups. Body height and weight accounted virtually for one-half of the

  17. Anencephalic fetuses and research embryos: subjects of rights?

    Directory of Open Access Journals (Sweden)

    Naara Luna

    Full Text Available The present article analyzes the emergence of social subjects in the form of beings which had previously been embedded in mother's bodies and which have later become defined and circumscribed by biomedicine: extracorporeal embryos, created by in vitro fertilization, and anencephalic fetuses. The embryos were at the center of the controversy regarding their use in scientific research during the debates for the approval of Brazil's new biosecurity law. Anencephalic fetuses became the center of a debate regarding the relaxing of Brazil's abortion laws. This article analyzes mass media news stories provided mostly by a systematic review of articles published in O Globo newspaper between 2000 and 2005 in order to recover the arguments presented in these debates. The arguments to justify or ban embryo research or to anticipate the birth of anencephalic fetuses coincide, in large part, because the are derived from the same value configuration and are founded upon the person: Dumont's individual-as-value.

  18. User Experience Research: Modelling and Describing the Subjective

    Directory of Open Access Journals (Sweden)

    Michael Glanznig

    2012-10-01

    Full Text Available User experience research in the field of human-computer interaction tries to understand how humans experience the interaction with technological artefacts. It is a young and still emerging field that exists in an area of tension. There is no consensus on how the concept of user experience should be defined or on how it should be researched. This paper focuses on two major strands of research in the field that are competing. It tries to give an overview over both and relate them to each other.Both start from the same premise: usability (focusing on performance is not enough. It is only part of the interaction with technological artefacts. And further: user experience is not very different from experience in general. Then they develop quite different accounts of the concept. While one focuses more on uncovering the objective in the subjective, on the precise and the formal, the other one stresses the ambiguous, the human and suggests to live with the subjectivity that is inherent in the concept of (user experience. One focuses more on evaluation rather than design and the other more on design than evaluation. One is a model and the other one more a framework of thought.Both can be criticised. The model can be questioned in terms of validity and the results of the other approach do not easily generalize across contexts – the reliability can be questioned. Sometimes the need for a unified view in user experience research is emphasized. While I doubt the possibility of a unified view I think it is possible to combine the two approaches. This combination has only rarely been attempted and not been critically reflected.

  19. Archives of Medical Research: an historical and subject coverage overview.

    Science.gov (United States)

    Lozoya, X; Rivera-Arce, E; Domínguez, F; Arellano, M L; Muñoz, O

    1995-01-01

    A bibliometric study about the subject content of the articles published in the Mexican scientific journal Archives of Medical Research is reported. The journal, published by the Mexican Institute of Social Security (IMSS), is comprised of 100 regular issues and 12 special supplements giving a total amount of 1,424 reports on medical research performed in Mexico during the last 25 years. According to the type of studies published during this period, we found that there is a similar percent of biomedical and clinical reports in the journal (47 and 42%, respectively) and a low proportion of epidemiological and medical educational reports (8 and 3%, respectively). Six thematic areas of research have been permanently published in this journal: investigations on infectious and neurological diseases being the areas mainly represented (34% of the total, corresponding to 17% in each area), followed by studies in reproductive biology (10%) and endocrine (7%), oncological (5%) and cardiovascular (3%) diseases. The tendency of the subjects covered by the journal during this period shows an increment in reports on infectious and parasitic disorders together with an increase in publications related to medicinal plant pharmacology; reproductive biology and endocrine studies show also an increasing tendency. On the other hand, a moderate decrease in studies related to neurological, oncological and cardiovascular diseases is observed. The origin of contributions during the last five years has balanced the proportion of papers published from IMSS scientists, other Mexican biomedical researchers and foreign contributions, thus reflecting favorably the recent changes in the journal's policies. This journal represents a clear example of a scientific publication edited in a developing country, originating as a national publication that evolved progressively into an international biomedical journal.

  20. Experimental Investigations of Tension Piles in Sand Subjected to Static and Cyclic Loading

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The present thesis regards the behavior of the piles in jacket pile foundations used for offshore wind turbines. The piles are often loaded in tension because of the combination of wind and wave conditions and the low self-weight of the wind turbine. The repeated cyclic loading can lead...... to accumulated upwards displacement of the piles and, thus, undesired deflection of the wind turbine structure. This study concerns the effect of cyclic loading on a pile installed in dense sand and loaded in tension. A new laboratory test setup was constructed to make these pile load tests. The thesis discusses...... the advantages and disadvantages of the test setup. The results of cyclic loading tests showed that the loading conditions are very important for the behavior of piles. Some wind and wave conditions can be beneficial and increase the pile capacity while other conditions can be damaging and reduce the pile...

  1. Safety Analysis of Dual Purpose Metal Cask Subjected to Impulsive Loads due to Aircraft Engine Crash

    Science.gov (United States)

    Shirai, Koji; Namba, Kosuke; Saegusa, Toshiari

    In Japan, the first Interim Storage Facility of spent nuclear fuel away from reactor site is being planned to start its commercial operation around 2010, in use of dual-purpose metal cask in the northern part of Main Japan Island. Business License Examination for safety design approval has started since March, 2007. To demonstrate the more scientific and rational performance of safety regulation activities on each phase for the first license procedure, CREPEI has executed demonstration tests with full scale casks, such as drop tests onto real targets without impact limiters(1) and seismic tests subjected to strong earthquake motions(2). Moreover, it is important to develop the knowledge for the inherent security of metal casks under extreme mechanical-impact conditions, especially for increasing interest since the terrorist attacks from 11th September 2001(3)-(6). This paper presents dynamic mechanical behavior of the metal cask lid closure system caused by direct aircraft engine crash and describes calculated results (especially, leak tightness based on relative dynamic displacements between metallic seals). Firstly, the local penetration damage of the interim storage facility building by a big passenger aircraft engine crash (diameter 2.7m, length 4.3m, weight 4.4ton, impact velocity 90m/s) has been examined. The reduced velocity is calculated by the local damage formula for concrete structure with its thickness of 70cm. The load vs. time function for this reduced velocity (60m/s) is estimated by the impact analysis using Finite Element code LS-DYNA with the full scale engine model onto a hypothetically rigid target. Secondly, as the most critical scenarios for the metal cask, two impact scenarios (horizontal impact hitting the cask and vertical impact onto the lid metallic seal system) are chosen. To consider the geometry of all bolts for two lids, the gasket reaction forces and the inner pressure of the cask cavity, the detailed three dimensional FEM models are

  2. Ultimate Load Capacity and Behavior of Thin-Walled Curved-Steel Square Struts, Subjected to Compressive Load

    Directory of Open Access Journals (Sweden)

    S.Mohammad Reza Mortazavi

    2016-06-01

    Full Text Available There have been some experimental tests on hollow curved-steel struts with thin-walled square sections, in order to investigate their general behavior, particularly their capacity for bearing differing loads. One set of square tubes are cold-formed into segments of circular arcs with curvature radii, equal to 4000 mm. Different lengths of curved struts are fabricated so as to cover a practical range of slenderness ratios. The struts tests were pin-ended and had slenderness ratios, based on the straight length between ends ranging from 31-126. The cold-forming operation induces initial inelastic behavior and associated residual stresses. There is, therefore, an interaction among material effects, such as the strain hardening capacity, the Bauschinger effect, strain aging, and residual stresses, together with the significant geometrical effect of the initial curvature, caused by the cold-forming operation. Eventually the results from three series of tests, which are taken on fully-aged and stress-relief-annealed square curved struts, are compared. The variations in load carrying response are discussed.

  3. Research ethics in Internet-enabled research: human subjects issues and methodological myopia.

    Science.gov (United States)

    Walther, Joseph B

    2002-01-01

    As Internet resources are used more frequently for research on social and psychological behavior, concerns grow about whether characteristics of such research affect human subjects protections. Early efforts to address such concerns have done more to identify potential problems than to evaluate them or to seek solutions, leaving bodies charged with human subjects oversight in a quagmire. This article critiques some of these issues in light of the US Code of Federal Regulations' policies for the Protection of Human Subjects, and argues that some of the issues have no pertinence when examined in the context of common methodological approaches that previous commentators failed to consider. By separating applicable contexts from those that are not, and by identifying cases where subjects' characteristics are irrelevant and/or impossible to provide, oversight committees may be able to consider research applications more appropriately, and investigators may be less ethically bound to ascertain and demonstrate those characteristics.

  4. Microstructure of Commercial Purity Titanium Subjected to Complex Loading by the Kobo Method

    Directory of Open Access Journals (Sweden)

    Kawałko J.

    2016-03-01

    Full Text Available Observations of refined microstructure of Commercial Purity titanium for applications in biomedical devices has been carried out. Refinement of titanium microstructure has been performed in process with complex strain scheme. Materials investigated in this work were: Commercial Purity titanium grade 2 and grade 4. Samples of as received materials were subjected to plastic deformation in complex loading process of extrusion combined with oscillation twisting (KoBo extrusion. Both types of samples were deformed in single step of extrusion, in temperature of 450 °C, with extrusion ratio 19.14 and 12.25 for grade 2 titanium and grade 4 titanium, respectively. Initial mean grain diameter for both types of materials was approximately 30 μm. Samples were investigated by means of crystal orientation microscopy. In both cases considerable microstructure refinement has been observed. Microstructures of deformed samples are heterogenous and consist of both elongated and fine equiaxed grains. Elongated grains (lamellae are separated by High Angle Grain Boundaries and feature internal structure with subgrains and dislocation walls. Grain refinement is stronger in material with higher extrusion ratio and mean grain diameter in this case is equal to 1.48 μm compared to 8.07 μm. in material with lower extrusion ratio. Mean misorientation angle (24° and 27° for grade 4 and grade 2 titanium indicates high fraction of HAGBs in microstructures of KoBo deformed samples. Misorientation fluctuations inside grains have been analyzed and distinct curvature of crystal lattice have been observed. Hardness of samples after plastic deformation increased from 174.6±3.4 and 234.9±3.5 to 205.0±3.2 and 251.2±2.2 for titanium grade 2 and grade 4 respectively.

  5. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  6. Soil Respiration and Belowground Carbon Stores Among Salt Marshes Subjected to Increasing Watershed Nitrogen Loadings in Southern New England

    Science.gov (United States)

    Coastal salt marshes are ecosystems located between the uplands and sea, and because of their location are subject to increasing watershed nutrient loadings and rising sea levels. Residential development along the coast is intense, and there is a significant relationship between...

  7. Bone reactions adjacent to titanium implants with different surface characteristics subjected to static load. A study in the dog (II)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    The purpose of the present study was to compare bone reactions adjacent to titanium implants with either a titanium plasma-sprayed (TPS) or a machined surface subjected to lateral static loading induced by an expansion force. In 3 labrador dogs, the 2nd, 3rd and 4th mandibular premolars were...

  8. Bone reactions at implants subjected to experimental peri-implantitis and static load. A study in the dog

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2002-01-01

    AIM: The aim of the present experiment was to study peri-implant tissue reactions to lateral static load at implants subjected to experimental mucositis or peri-implantitis. MATERIAL AND METHODS: 5 beagle dogs were used. The mandibular premolars were extracted. After 12 weeks, 3 implants were...

  9. Generic rules of mechano-regulation combined with subject specific loading conditions can explain bone adaptation after THA.

    Directory of Open Access Journals (Sweden)

    Tomasz D Szwedowski

    Full Text Available Bone adaptation after total hip arthroplasty is associated with the change in internal load environment, and can result in compromised bone stock, which presents a considerable challenge should a revision procedure be required. Under the assumption of a generic mechano-regulatory algorithm for governing bone adaptation, the aim of this study was to understand the contribution of subject specific loading conditions towards explaining the local periprosthetic remodelling variations in patients. CT scans of 3 consecutive THA patients were obtained and used for the construction of subject specific finite element models using verified musculoskeletal loading and physiological boundary conditions. Using either strain energy density or equivalent strain as mechano-transduction signals, predictions of bone adaptation were compared to DEXA derived BMD changes from 7 days to 12 months post-implantation. Individual changes in BMD of up to 33.6% were observed within the 12 month follow-up period, together with considerable inter-patient variability of up to 26%. Estimates of bone adaptation using equivalent strain and balanced loading conditions led to the best agreement with in vivo measured BMD, with RMS errors of only 3.9%, 7.3% and 7.3% for the individual subjects, compared to errors of over 10% when the loading conditions were simplified.This study provides evidence that subject specific loading conditions and physiological boundary constraints are essential for explaining inter-patient variations in bone adaptation patterns. This improved knowledge of the rules governing the adaptation of bone following THA helps towards understanding the interplay between mechanics and biology for better identifying patients at risk of excessive or problematic periprosthetic bone atrophy.

  10. Experimental study of a macrocrack propagation in a concrete specimen subjected to creep loading

    Directory of Open Access Journals (Sweden)

    Martin E.

    2013-07-01

    Full Text Available Structures managers need a better prediction of the delayed failure of concrete structures, especially for very important structures like nuclear power plant encasement. Sustained loadings at high level (above 75% of loading capacity of the structure, can lead to structure failure after some time. In this study, a series of 4-point bending tests were performed in order to characterize the creep behaviour of pre-cracked beams under high load level. The specimens were made of normal strength concrete. A power law relationship is observed between the secondary deflection creep rate and the failure time. It is also shown that when crack propagation occurs during the creep loading, the creep deflection rate increases with the creep loading level and with the crack propagation rate.

  11. Effect of potassium and calcium loading on healthy subjects under hypokinesia and physical exercise with fluid and salt supplements

    Science.gov (United States)

    Zorbas, Yan G.; Naexu, Konstantin A.; Federenko, Youri F.

    1995-08-01

    The objective of this investigation was to determine the acute responses to the electrolyte challenges under hypokinesia and physical exercise (PE) of different intensities with fluid and salt supplementation (FSS). The studies were performed on 12 physically healthy male volunteers aged 19-24 years under 364 days of hypokinesia (decreased number of steps per day) with a set of PE with FSS. The volunteers were divided into two equal groups. The first group was subjected to a set of intensive PE and the second group was submitted to a set of moderate PE. Both groups of subjects consumed daily water and salt supplements that aimed to increase the body hydration level. For simulation of the hypokinetic effect all subjects were kept under an average of 3000 steps per day. Functional tests with a potassium chloride (KCl) and calcium lactate (Cal) load were performed during the hypokinetic period of 364 days and the 60-day prehypokinetic period that served as control, while both groups of subjects consumed daily calcium and potassium supplements. The concentration of electrolyte and hormone levels in the blood and their excretion rate in urine were determined. Renal excretion of calcium and potassium and the blood concentration thereof increased markedly in both groups of subjects. With the potassium chloride load tests the increased potassium excretion was accompanied by higher aldosterone and insulin blood levels, and with the calcium lactate load tests the increased calcium excretion was accompanied by a decreased parathyroid content in the blood. FSS and PE, regardless of intensity, failed to attenuate calcium and potassium losses. Additional intake of KCl and Cal also failed to normalize potassium and calcium abnormalities. It was concluded that during the KCl and Cal loading tests, the increased losses of potassium and calcium in the hypokinetic subjects were due to the inability of their bodies to retain these electrolytes, and that electrolyte abnormalities could

  12. The Use of Single-Subject Research to Identify Evidence-Based Practice in Special Education

    Science.gov (United States)

    Horner, Robert H.; Carr, Edward G.; Halle, James; McGee, Gail; Odom, Samuel; Wolery, Mark

    2005-01-01

    Single-subject research plays an important role in the development of evidence-based practice in special education. The defining features of single-subject research are presented, the contributions of single-subject research for special education are reviewed, and a specific proposal is offered for using single-subject research to document…

  13. Brittle materials at high-loading rates: an open area of research

    Science.gov (United States)

    Forquin, Pascal

    2017-01-01

    Brittle materials are extensively used in many civil and military applications involving high-strain-rate loadings such as: blasting or percussive drilling of rocks, ballistic impact against ceramic armour or transparent windshields, plastic explosives used to damage or destroy concrete structures, soft or hard impacts against concrete structures and so on. With all of these applications, brittle materials are subjected to intense loadings characterized by medium to extremely high strain rates (few tens to several tens of thousands per second) leading to extreme and/or specific damage modes such as multiple fragmentation, dynamic cracking, pore collapse, shearing, mode II fracturing and/or microplasticity mechanisms in the material. Additionally, brittle materials exhibit complex features such as a strong strain-rate sensitivity and confining pressure sensitivity that justify expending greater research efforts to understand these complex features. Currently, the most popular dynamic testing techniques used for this are based on the use of split Hopkinson pressure bar methodologies and/or plate-impact testing methods. However, these methods do have some critical limitations and drawbacks when used to investigate the behaviour of brittle materials at high loading rates. The present theme issue of Philosophical Transactions A provides an overview of the latest experimental methods and numerical tools that are currently being developed to investigate the behaviour of brittle materials at high loading rates. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  14. Dynamic Response Analysis of Storage Cask Lid Structure Subjected to Lateral Impact Load of Aircraft Engine Crash

    Energy Technology Data Exchange (ETDEWEB)

    Almomania, Belal; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Lee, Sanghoon [Keimyung Univ., Daegu (Korea, Republic of)

    2015-10-15

    Several numerical methods and tests have been carried out to measure the capability of storage cask to withstand extreme impact loads. Testing methods are often constrained by cost, and difficulty in preparation for several impact conditions with different applied loads, and areas of impact. Instead, analytic method is an acceptable process that can easily apply different impact conditions for the evaluation of cask integrity. The aircraft engine impact is considered as one of the most critical impact accidents on the storage cask that significantly affects onto the lid closure system and may cause a considerable release of radioactive materials. This paper presents a method for evaluating the dynamic responses of one upper metal cask lid closure without impact limiters subjected to lateral impact of an aircraft engine with respect to variation of the impact velocity. An assessment method to predict damage response due to the lateral engine impact onto metal storage cask has been studied by using computer code LS-DYNA. The dynamic behavior of the lid movements was successfully calculated by utilizing a simplified finite element cask model, which showed a good agreement with the previous research. The simulation analyses results showed that no significant plastic deformation for bolts, lid, and the cask body. In this study, the lid opening and sliding displacements are considered as the major factors in initiating the leakage path. This analysis may be useful for evaluating the instantaneous leakage rates in a connection with the sliding and opening displacements between the lid and the flange to ensure that the radiological consequences caused by an aircraft engine crash accident during the storage phase are within the permissible level.

  15. Magnetic Nanoparticles: A Subject for Both Fundamental Research and Applications

    Directory of Open Access Journals (Sweden)

    S. Bedanta

    2013-01-01

    Full Text Available Single domain magnetic nanoparticles (MNPs have been a vivid subject of intense research for the last fifty years. Preparation of magnetic nanoparticles and nanostructures has been achieved by both bottom-up and top-down approaches. Single domain MNPs show Néel-Brown-like relaxation. The Stoner-Wohlfarth model describes the angular dependence of the switching of the magnetization of a single domain particle in applied magnetic fields. By varying the spacing between the particles, the inter-particle interactions can be tuned. This leads to various supermagnetic states such as superparamagnetism, superspin glass, and superferromagnetism. Recently, the study of the magnetization dynamics of such single domain MNPs has attracted particular attention, and observations of various collective spin wave modes in patterned nanomagnet arrays have opened new avenues for on-chip microwave communications. MNPs have the potential for various other applications such as future recording media and in medicine. We will discuss the various aspects involved in the research on MNPs.

  16. Load Sensing Systems - A Review of the Research Contributions Throughout the Last Decades

    DEFF Research Database (Denmark)

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

    2004-01-01

    The paper describes the major research contributions made in the research of hydraulic load sensing systems throughout the last decades. Furthermore, the paper investigates the efforts put into electronic load sensing and the most promising alternatives to load sensing systems. Finally, the paper...

  17. Research on the Transient Characteristics of Microgrid with Pulsed Load

    Directory of Open Access Journals (Sweden)

    Jianke Li

    2015-01-01

    Full Text Available Unlike traditional load, pulsed load typically features small average power and large peak power. In this paper, the mathematic models of microgrid consisting of synchronous generator and pulsed load are established. Average Magnitude Difference Compensate Function (AMDCF is proposed to calculate the frequency of synchronous generator, and, based on AMDCF, relative deviation rate (RDR which characterizes the impact of pulsed load on the AC side of grid is firstly defined and this paper describes calculation process in detail. Insulated Gate Bipolar Transistor (IGBT is used as DC switch to control the on/off state of resistive load for simulating pulsed load, the period and duty-cycle of the pulsed load are simulated by setting the gate signal of IGBT, and the peak power of the pulsed load is simulated by setting the resistance. The system dynamic characteristics under pulsed load are analyzed in detail, and the influence of duty-cycle, period, peak power, and filter capacitance of the pulsed load on system dynamic indicators is studied and validated experimentally.

  18. Effects of vision and cognitive load on static postural control in subjects with and without patellofemoral pain syndrome.

    Science.gov (United States)

    Zeinalzadeh, Afsaneh; Talebian, Saeed; Naghdi, Soofia; Salavati, Mahyar; Nazary-Moghadam, Salman; Zeynalzadeh Ghoochani, Bahareh

    2018-04-01

    To compare the effects of vision and cognitive load on static postural control in subjects with and without patellofemoral pain syndrome (PFPS). Twenty-eight PFPS patients and 28 controls participated in the study. Postural control was assessed in isolation as well as with visual manipulation and cognitive loading on symptomatic limb. The outcome measures of postural control were quantified in terms of area, anterior-posterior (AP), medial-lateral (ML), and mean velocity (MV) of the displacements of center of pressure (COP). In addition, cognitive performance (auditory Stroop task) was measured in the forms of average reaction time and error ratio in baseline (sitting) and different postural conditions. PFPS subjects showed greater increases in area (p = 0.01), AP (p = 0.01), and ML (p = 0.05) displacements of COP in the blindfolded tasks as compared to control group. However, cognitive load did not differently affect postural control in the two groups. Although PFPS and control group had similar reaction times in the sitting position (p = 0.29), PFPS subjects had longer reaction times than healthy subjects in dual task conditions (p = 0.04). Visual inputs seem to be essential for discriminating postural control between PFPS and healthy individuals. PFPS patients biased toward decreasing cognitive performance more than healthy subjects when they perform the single leg stance and cognitive task concurrently.

  19. Single-Subject Studies in Translational Nutrition Research.

    Science.gov (United States)

    Schork, Nicholas J; Goetz, Laura H

    2017-08-21

    There is a great deal of interest in personalized, individualized, or precision interventions for disease and health-risk mitigation. This is as true of nutrition-based intervention and prevention strategies as it is for pharmacotherapies and pharmaceutical-oriented prevention strategies. Essentially, technological breakthroughs have enabled researchers to probe an individual's unique genetic, biochemical, physiological, behavioral, and exposure profile, allowing them to identify very specific and often nuanced factors that an individual might possess, which may make it more or less likely that he or she responds favorably to a particular intervention (e.g., nutrient supplementation) or disease prevention strategy (e.g., specific diet). However, as compelling and intuitive as personalized nutrition might be in the current era in which data-intensive biomedical characterization of individuals is possible, appropriately and objectively vetting personalized nutrition strategies is not trivial and requires novel study designs and data analytical methods. These designs and methods must consider a very integrated use of the multiple contemporary biomedical assays and technologies that motivate them, which adds to their complexity. Single-subject or N-of-1 trials can be used to assess the utility of personalized interventions and, in addition, can be crafted in such a way as to accommodate the necessarily integrated use of many emerging biomedical technologies and assays. In this review, we consider the motivation, design, and implementation of N-of-1 trials in translational nutrition research that are meant to assess the utility of personalized nutritional strategies. We provide a number of example studies, discuss appropriate analytical methods given the complex data they generate and require, and consider how such studies could leverage integration of various biomarker assays and clinical end points. Importantly, we also consider the development of strategies and

  20. Effects of a water-loading test on intraocular pressure and corneal hysteresis in young healthy subjects.

    Science.gov (United States)

    Ulaş, Fatih; Balbaba, Mehmet; Celebi, Serdal

    2014-02-01

    To evaluate the influence of a water-loading test on corneal compensated intraocular pressure (IOPcc) and corneal hysteresis (CH) in young healthy subjects. Forty healthy adult subjects (20 female and 20 male), with a mean age of 27.55±2.57 years (range, 24 to 35 y), participated in this prospective study. IOPcc and CH were measured for 1 eye from each participant with an Ocular Response Analyser. These measurements were taken before and 10, 20, and 30 minutes after water loading. Thirty-seven right and 3 left eyes of the 40 subjects fulfilled the study's inclusion criteria. A statistically significant increase in IOPcc was observed between 0 and 10 minutes (P=0.002) and a significant decrease between 10 and 30 minutes (Pcorneal biomechanical properties.

  1. Statistical analysis of the variation of floor vibrations in nuclear power plants subject to seismic loads

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Vilho [VTT Technical Research Centre of Finland Ltd, Kemistintie 3, 02230 Espoo (Finland); Li, Yue [Dept. of Civil Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States); Fülöp, Ludovic, E-mail: ludovic.fulop@vtt.fi [VTT Technical Research Centre of Finland Ltd, Kemistintie 3, 02230 Espoo (Finland)

    2016-12-01

    Highlights: • Floor flexibility plays a non-negligible role in amplifying horizontal vibrations. • COV of in-floor horizontal and vertical acceleration are 0.15–0.25 and 0.25–0.55. • In-floor variation of vibrations is higher in lower floors. • Floor spectra from limited nodes underestimates vibrations by a factor of 1.5–1.75. - Abstract: Floor vibration of a reactor building subjected to seismic loads was investigated, with the aim of quantifying the variability of vibrations on each floor. A detailed 3D building model founded on the bedrock was excited simultaneously in three directions by artificial accelerograms compatible with Finnish ground response spectra. Dynamic simulation for 21 s was carried out using explicit time integration. The extracted results of the simulation were acceleration in several floor locations, transformed to pseudo-acceleration (PSA) spectra in the next stage. At first, the monitored locations on the floors were estimated by engineering judgement in order to arrive at a feasible number of floor nodes for post processing of the data. It became apparent that engineering judgment was insufficient to depict the key locations with high floor vibrations, which resulted in un-conservative vibration estimates. For this reason, a more systematic approach was later considered, in which nodes of the floors were selected with a more refined grid of 2 m. With this method, in addition to the highest PSA peaks in all directions, the full vibration distribution in each floor can be determined. A statistical evaluation of the floor responses was also carried out in order to define floor accelerations and PSAs with high confidence of non-exceedance. The conclusion was that in-floor variability can be as high as 50–60% and models with sufficiently dense node grids should be used in order to achieve a realistic estimate of floor vibration under seismic action. The effects of the shape of the input spectra, damping, and flexibility of the

  2. Optimization of structures subjected to dynamic load: deterministic and probabilistic methods

    Directory of Open Access Journals (Sweden)

    Élcio Cassimiro Alves

    Full Text Available Abstract This paper deals with the deterministic and probabilistic optimization of structures against bending when submitted to dynamic loads. The deterministic optimization problem considers the plate submitted to a time varying load while the probabilistic one takes into account a random loading defined by a power spectral density function. The correlation between the two problems is made by one Fourier Transformed. The finite element method is used to model the structures. The sensitivity analysis is performed through the analytical method and the optimization problem is dealt with by the method of interior points. A comparison between the deterministic optimisation and the probabilistic one with a power spectral density function compatible with the time varying load shows very good results.

  3. Behavior of sandwich panels subjected to bending fatigue, axial compression loading and in-plane bending

    Science.gov (United States)

    Mathieson, Haley Aaron

    This thesis investigates experimentally and analytically the structural performance of sandwich panels composed of glass fibre reinforced polymer (GFRP) skins and a soft polyurethane foam core, with or without thin GFRP ribs connecting skins. The study includes three main components: (a) out-of-plane bending fatigue, (b) axial compression loading, and (c) in-plane bending of sandwich beams. Fatigue studies included 28 specimens and looked into establishing service life (S-N) curves of sandwich panels without ribs, governed by soft core shear failure and also ribbed panels governed by failure at the rib-skin junction. Additionally, the study compared fatigue life curves of sandwich panels loaded under fully reversed bending conditions (R=-1) with panels cyclically loaded in one direction only (R=0) and established the stiffness degradation characteristics throughout their fatigue life. Mathematical models expressing fatigue life and stiffness degradation curves were calibrated and expanded forms for various loading ratios were developed. Approximate fatigue thresholds of 37% and 23% were determined for non-ribbed panels loaded at R=0 and -1, respectively. Digital imaging techniques showed significant shear contribution significantly (90%) to deflections if no ribs used. Axial loading work included 51 specimens and examined the behavior of panels of various lengths (slenderness ratios), skin thicknesses, and also panels of similar length with various rib configurations. Observed failure modes governing were global buckling, skin wrinkling or skin crushing. In-plane bending involved testing 18 sandwich beams of various shear span-to-depth ratios and skin thicknesses, which failed by skin wrinkling at the compression side. The analytical modeling components of axially loaded panels include; a simple design-oriented analytical failure model and a robust non-linear model capable of predicting the full load-displacement response of axially loaded slender sandwich panels

  4. Permeability Evolution in Natural Fractures Subject to Cyclic Loading and Gouge Formation

    Science.gov (United States)

    Vogler, Daniel; Amann, Florian; Bayer, Peter; Elsworth, Derek

    2016-09-01

    Increasing fracture aperture by lowering effective normal stress and by inducing dilatant shearing and thermo-elastic effects is essential for transmissivity increase in enhanced geothermal systems. This study investigates transmissivity evolution for fluid flow through natural fractures in granodiorite at the laboratory scale. Processes that influence transmissivity are changing normal loads, surface deformation, the formation of gouge and fracture offset. Normal loads were varied in cycles between 1 and 68 MPa and cause transmissivity changes of up to three orders of magnitude. Similarly, small offsets of fracture surfaces of the order of millimeters induced changes in transmissivity of up to three orders of magnitude. During normal load cycling, the fractures experienced significant surface deformation, which did not lead to increased matedness for most experiments, especially for offset fractures. The resulting gouge material production may have caused clogging of the main fluid flow channels with progressing loading cycles, resulting in reductions of transmissivity by up to one order of magnitude. During one load cycle, from low to high normal loads, the majority of tests show hysteretic behavior of the transmissivity. This effect is stronger for early load cycles, most likely when surface deformation occurs, and becomes less pronounced in later cycles when asperities with low asperity strength failed. The influence of repeated load cycling on surface deformation is investigated by scanning the specimen surfaces before and after testing. This allows one to study asperity height distribution and surface deformation by evaluating the changes of the standard deviation of the height, distribution of asperities and matedness of the fractures. Surface roughness, as expressed by the standard deviation of the asperity height distribution, increased during testing. Specimen surfaces that were tested in a mated configuration were better mated after testing, than

  5. Evaluation of Thin Kevlar-Epoxy Fabric Panels Subjected to Shear Loading

    Science.gov (United States)

    Baker, Donald J.

    1996-01-01

    The results of an analytical and experimental investigation of 4-ply Kevlar-49-epoxy panels loaded by in-plane shear are presented. Approximately one-half of the panels are thin-core sandwich panels and the other panels are solid-laminate panels. Selected panels were impacted with an aluminum sphere at a velocity of either 150 or 220 ft/sec. The strength of panels impacted at 150 ft/sec was not reduced when compared to the strength of the undamaged panels, but the strength of panels impacted at 220 ft/sec was reduced by 27 to 40 percent. Results are presented for panels that were cyclically loaded from a load less than the buckling load to a load in the postbuckling load range. The thin-core sandwich panels had a lower fatigue life than the solid panels. The residual strength of the solid and sandwich panels cycled more than one million cycles exceeded the baseline undamaged panel strengths. The effect of hysteresis in the response of the sandwich panels is not significant. Results of a nonlinear finite element analysis conducted for each panel design are presented.

  6. Evaluation of a subject-specific finite-element model of the equine metacarpophalangeal joint under physiological load.

    Science.gov (United States)

    Harrison, Simon M; Whitton, R Chris; Kawcak, Chris E; Stover, Susan M; Pandy, Marcus G

    2014-01-03

    The equine metacarpophalangeal (MCP) joint is frequently injured, especially by racehorses in training. Most injuries result from repetitive loading of the subchondral bone and articular cartilage rather than from acute events. The likelihood of injury is multi-factorial but the magnitude of mechanical loading and the number of loading cycles are believed to play an important role. Therefore, an important step in understanding injury is to determine the distribution of load across the articular surface during normal locomotion. A subject-specific finite-element model of the MCP joint was developed (including deformable cartilage, elastic ligaments, muscle forces and rigid representations of bone), evaluated against measurements obtained from cadaver experiments, and then loaded using data from gait experiments. The sensitivity of the model to force inputs, cartilage stiffness, and cartilage geometry was studied. The FE model predicted MCP joint torque and sesamoid bone flexion angles within 5% of experimental measurements. Muscle-tendon forces, joint loads and cartilage stresses all increased as locomotion speed increased from walking to trotting and finally cantering. Perturbations to muscle-tendon forces resulted in small changes in articular cartilage stresses, whereas variations in joint torque, cartilage geometry and stiffness produced much larger effects. Non-subject-specific cartilage geometry changed the magnitude and distribution of pressure and the von Mises stress markedly. The mean and peak cartilage stresses generally increased with an increase in cartilage stiffness. Areas of peak stress correlated qualitatively with sites of common injury, suggesting that further modelling work may elucidate the types of loading that precede joint injury and may assist in the development of techniques for injury mitigation. © 2013 Published by Elsevier Ltd.

  7. A deflection formula for single-span beams of constant section subjected to combined axial and transverse loads

    Science.gov (United States)

    Burke, Walter F

    1935-01-01

    In this paper there is presented a deflection formula for single-span beams of constant section subjected to combined axial and transverse loads of the types commonly encountered in airplane design. The form of the equation is obtainable by dimensional analysis. Tables and curves of the non dimensional coefficients are appended to facilitate the use of the formula. The equation is applied to the determination of the spring constant of a beam. Tables and curves are presented to show the variation of the spring constant with changes in the axial load and position along the beam.

  8. Research on a detection algorithm for abnormal state of load

    Directory of Open Access Journals (Sweden)

    Yu Dan

    2017-01-01

    Full Text Available This paper describes the development status and main problems of load monitoring, introduces the key technologies of load monitoring, and by using a load state monitoring system, emphatically illustrates a detection algorithm for abnormal state of the secondary load of the current transformer on the three-phase line of the power grid. The algorithm mainly achieves the real-time detection of abnormal state such as disconnection, short connection and series connected semiconductor. In the light of this algorithm, the working principle is explained, the model formula is worked out, and the state criterion is given. The load condition monitoring system is debugged, put into operation and tested in the pilot operation, and the results show that the algorithm has a good effect.

  9. COMMUNICATIVE COMPETENCE AS THE SUBJECT OF EDUCATIONAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Yuliya I. Аleyevskaya

    2016-09-01

    Full Text Available Introduction: the issue of development of the communicative competence is well studied in pedagogical theory and practice. Nevertheless there is no consensus among researchers regarding the interpretation of the notion. This fact determines the relevance of the subject in the context of the reform of the national higher education. The labour market puts forward increasing requirements to graduates’ adaption potential within the system “human – human”. This draws special attention to the problem of communicative co mpetence. Materials and Methods: the authors carried out a sociological research on the communicative component of the competence cluster among master’s degree students who specialise in pedagogical education in order to determine “the importance of weight indicators” of separate competencies. Results: the authors substantiate the necessity of broadening a communicative competence in conditions of transition to a multilevel system of higher education; define its essence and structure taking into account the generic unity of Bachelor’s and Master’s degree programmes. The article presents the informative content of communication components in accordance with the proposed structure of communicative competence, containing motivation-value-based, cognitive, activity-based, reflective and evaluative components. The authors show the potential of communicative competence in the context of the new federal state educational standards (FGOS VO 3+. Further the authors make analysis of the requirements set to graduates upon completion of undergraduate and graduate programmes in “Pedagogical Education”, specify the role of separate competencies in extending graduates’ communicative competence. Discussion and Conclusions: the results of the research presented in the article enable to specify the structure and content of the communicative competence of a university graduate, reflecting the willingness and ability to productive

  10. Therapeutic misconception in research subjects: development and validation of a measure.

    Science.gov (United States)

    Appelbaum, Paul S; Anatchkova, Milena; Albert, Karen; Dunn, Laura B; Lidz, Charles W

    2012-12-01

    Therapeutic misconception (TM), which occurs when research subjects fail to appreciate the distinction between the imperatives of clinical research and ordinary treatment, may undercut the process of obtaining meaningful consent to clinical research participation. Previous studies have found that TM is widespread, but progress in addressing TM has been stymied by the absence of a validated method for assessing its presence. The goal of this study was to develop and validate a theoretically grounded measure of TM, assess its diagnostic accuracy, and test previous findings regarding TM's prevalence. A total of 220 participants were recruited from clinical trials at four academic medical centers in the United States. Participants completed a 28-item Likert-type questionnaire to assess the presence of beliefs associated with TM, and a semistructured TM interview designed to elicit their perceptions of the nature of the clinical trial in which they were participating. Data from the questionnaires were subjected to factor analysis, and items with poor factor loadings were excluded. This resulted in a 10-item scale, with three strongly correlated factors and excellent internal consistency; the fit indices of the model across 10 training sets were consistent with the original results, suggesting a stable factor solution. The scale was validated against the TM interview, with significantly higher scores among subjects coded as displaying evidence of TM. Receiver operating curve (ROC) analysis based on a 10-fold internal cross-validation yielded area under the ROC (AUC) = 0.682 for any evidence of TM. When sensitivity (0.72) and specificity (0.61) were both optimized, positive predictive value was 0.65 and negative predictive value was 0.68, with a positive likelihood ratio of 1.89 and a negative likelihood ratio of 0.47. In all, 50.5% (n = 101) of the participants manifested evidence of TM on the TM interview, a somewhat lower rate than in most previous studies. The

  11. Stability analysis of shallow tunnels subjected to eccentric loads by a boundary element method

    Directory of Open Access Journals (Sweden)

    Mehdi Panji

    2016-08-01

    Full Text Available In this paper, stress behavior of shallow tunnels under simultaneous non-uniform surface traction and symmetric gravity loading was studied using a direct boundary element method (BEM. The existing full-plane elastostatic fundamental solutions to displacement and stress fields were used and implemented in a developed algorithm. The cross-section of the tunnel was considered in circular, square, and horseshoe shapes and the lateral coefficient of the domain was assumed as unit quantity. Double-node procedure of the BEM was applied at the corners to improve the model including sudden traction changes. The results showed that the method used was a powerful tool for modeling underground openings under various external as well as internal loads. Eccentric loads significantly influenced the stress pattern of the surrounding tunnel. The achievements can be practically used in completing and modifying regulations for stability investigation of shallow tunnels.

  12. Optimum Parameters of a Tuned Liquid Column Damper in a Wind Turbine Subject to Stochastic Load

    Science.gov (United States)

    Alkmim, M. H.; de Morais, M. V. G.; Fabro, A. T.

    2017-12-01

    Parameter optimization for tuned liquid column dampers (TLCD), a class of passive structural control, have been previously proposed in the literature for reducing vibration in wind turbines, and several other applications. However, most of the available work consider the wind excitation as either a deterministic harmonic load or random load with white noise spectra. In this paper, a global direct search optimization algorithm to reduce vibration of a tuned liquid column damper (TLCD), a class of passive structural control device, is presented. The objective is to find optimized parameters for the TLCD under stochastic load from different wind power spectral density. A verification is made considering the analytical solution of undamped primary system under white noise excitation by comparing with result from the literature. Finally, it is shown that different wind profiles can significantly affect the optimum TLCD parameters.

  13. Non-linear dynamic instability analysis of thin-walled stiffener beam subjected to uniform harmonic in-plane loading

    Science.gov (United States)

    Yadav, Amit; Panda, Sarat Kumar; Dey, Tanish

    2017-11-01

    Present analysis deals with nonlinear flexural-torsional vibration and dynamic instability of thin-walled stiffener beam with open section subjected to harmonic in-plane loading. The static and dynamic components of the applied harmonic in-plane loading are assumed to vary uniformly. A set of nonlinear partial differential equations (PDEs) describing the vibration of system is derived. Using Galerkin's method, these partial differential equations are reduced into coupled Mathieu equations. The steady state response of the system is determined by solving the condition for a non-trivial solution. The principal regions of parametric resonance are determined using the method suggested by Bolotin. The numerical results are presented to investigate the effect of aspect ratios, boundary conditions and static load factor on the frequency-amplitude responses and instability regions.

  14. Enterprising or altruistic selves? Making up research subjects in genetics research.

    Science.gov (United States)

    Tutton, Richard; Prainsack, Barbara

    2011-11-01

    The emergence of direct-to-consumer (DTC) personal genomics companies in 2007 was accompanied by considerable media attention and criticism from clinical geneticists and other health professionals, regulators, policy advisors, and ethicists. As well as offering genetic testing services, some firms are also engaged in building their own databases and conducting research with the data obtained from their customers. In this paper, we examine how one of these companies, 23andMe, is creating a certain kind of 'research subject' in opposition to that constituted in conventional forms of disease research. Drawing on debates about neoliberalism, contemporary health discourses and subjectivity, we consider two kinds of subjectivities produced through the discursive and material practices of 23andMe and UK Biobank, namely, 'enterprising' and 'altruistic' selves. We argue that the 23andMe model promotes the idea that curiosity about one's genome on the one hand, and participation in research on the other, are not only compatible but complementary aspects of being an entrepreneurial subject of contemporary health and medicine framed by the technologies of web 2.0. © 2011 The Authors. Sociology of Health & Illness © 2011 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.

  15. Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings.

    Science.gov (United States)

    Nikander, R; Kannus, P; Rantalainen, T; Uusi-Rasi, K; Heinonen, A; Sievänen, H

    2010-10-01

    The association of long-term sport-specific exercise loading with cross-sectional geometry of the weight-bearing tibia was evaluated among 204 female athletes representing five different exercise loadings and 50 referents. All exercises involving ground impacts (e.g., endurance running, ball games, jumping) were associated with thicker cortex at the distal and diaphyseal sites of the tibia and also with large diaphyseal cross-section, whereas the high-magnitude (powerlifting) and non-impact (swimming) exercises were not. Bones adapt to the specific loading to which they are habitually subjected. In this cross-sectional study, the association of long-term sport-specific exercise loading with the geometry of the weight-bearing tibia was evaluated among premenopausal female athletes representing 11 different sports. A total of 204 athletes were divided into five exercise loading groups, and the respective peripheral quantitative computed tomographic data were compared to data obtained from 50 physically active, non-athletic referents. Analysis of covariance was used to estimate the between-group differences. At the distal tibia, the high-impact, odd-impact, and repetitive low-impact exercise loading groups had approximately 30% to 50% (p < 0.05) greater cortical area (CoA) than the referents. At the tibial shaft, these three impact groups had approximately 15% to 20% (p < 0.05) greater total area (ToA) and approximately 15% to 30% (p < 0.05) greater CoA. By contrast, both the high-magnitude and repetitive non-impact groups had similar ToA and CoA values to the reference group at both tibial sites. High-impact, odd-impact, and repetitive low-impact exercise loadings were associated with thicker cortex at the distal tibia. At the tibial shaft, impact loading was not only associated with thicker cortex, but also a larger cross-sectional area. High-magnitude exercise loading did not show such associations at either site but was comparable to repetitive non-impact loading

  16. Behavior of R/C Cylindrical Panel Subjected to Combined Axial and Shear Loadings

    OpenAIRE

    Hara, Takashi

    2009-01-01

    p. 1722-1730 Reinforced concrete (R/C) cylindrical panels have been applied to the roof or the underground structures. Also, in constructing a high rise building, an R/C wall is often used to improve the lateral rigidity of the building comparing with beam column systems under wind or seismic loading. In this paper, the behavior of R/C cylindrical shell under combined axial and lateral shear loadings is analyzed numerically. R/C cylindrical shells are often adopted for the core wa...

  17. A model of market power in electricity industries subject to peak load pricing

    Energy Technology Data Exchange (ETDEWEB)

    Arellano, Maria-Soledad [Center for Applied Economics (CEA), Department of Industrial Engineering, University of Chile, Republica 701, Santiago (Chile); Serra, Pablo [Department of Economics, University of Chile, Diagonal Paraguay 257, Santiago (Chile)

    2007-10-15

    This paper studies the exercise of market power in price-regulated electricity industries under peak-load pricing and merit order dispatching, but where investment decisions are taken by independent generating companies. Within this context, we show that producers can exercise market power by under-investing in base-load capacity, compared to the welfare-maximizing configuration. We also show that when there is free entry with an exogenous fixed entry cost that is later sunk, more intense competition results in higher welfare but fewer firms. (author)

  18. Bone reactions adjacent to titanium implants subjected to static load. A study in the dog (I)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri-implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental...... Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling...

  19. Analysis of shell-type structures subjected to time-dependent mechanical and thermal loading

    Science.gov (United States)

    Simitses, G. J.

    1989-01-01

    The objective is to develop a general mathematical model and solution methodologies for analyzing structural response of thin, metallic shell-type structures under large transient, cyclic, or static thermomechanical loads. Among the system responses, which are associated with these load conditions, are thermal buckling, creep buckling, and racheting. Thus, geometric as well as material-type nonlinearities (of high order) can be anticipated and must be considered in the development of the mathematical model. Furthermore, this must also be accommodated in the solution procedures.

  20. Fluid electrolyte changes in trained subjects after water loading and during restriction of muscular activity and chronic hyperhydration.

    Science.gov (United States)

    Zorbas, Y G; Federenko, Y F; Naexu, K A

    1996-09-01

    The objective of this investigation was to determine fluid electrolyte changes after water-loading tests and during hypokinesia (decreased number of km taken per day) and daily intake of fluid and salt supplementation (FSS). The studies during hypokinesia (HK) were performed for 364 d on 30 endurance-trained male volunteers in the age range of 23-26 yr, with an average peak oxygen uptake, POU, of 64 mL/kg/min. All volunteers were divided into three equal groups: 10 volunteers were placed on a continuous regime of exercise of 14.4 km/d and served as control subjects (CS); 10 volunteers were submitted to continuous HK without FSS and were considered as the unsupplemented hypokinetic subjects (UHS); and 10 volunteers were under continuous HK and FSS and were considered as the supplemented hypokinetic subjects (SHS). For the simulation of the hypokinetic effect, the UHS and SHS groups were kept continuously under an average of 2.7 km/d for the duration of the study. Prior to exposure to HK, the two groups of volunteers were on the same exercise regime as the control group. During a 60-d preexperimental period and during the remainder of the study, water-loading tests with a water load of 20 mL/kg body wt/min were performed, and urinary and plasma electrolytes (sodium, potassium, calcium, and magnesium) were measured. In the SHS group, urinary excretion of electrolytes and plasma electrolyte content decreased, while in the UHS these values increased after water loading tests and during HK. Based on the obtained data, it is concluded that chronic hyperhydration may be used to prevent or minimize urinary and plasma electrolyte changes in endurance-trained volunteers after water-loading tests and during prolonged restriction of muscular activity.

  1. Comparison of the perceived subjective exertion and total load lifted response in resistance exercises performed on stable and unstable platforms

    Directory of Open Access Journals (Sweden)

    Liliane Cunha Aranda

    2015-03-01

    Full Text Available This study aimed to compare the perceived subjective exertion (PSE and total load lifted in resistance exercises performed on stable platforms (SP and unstable platforms (UP. Participants were 20 men (24.6 ± 3.4 years, 179 ± 0.1 cm, 80.6 ± 9.1 kg and 11.8 ± 3.4% fat. Each subject performed a 15 maximum repetition test in half squat exercises (soil and balance discs, pronated barbell row (soil and bosu and biceps curl (soil and balance discs in both conditions. PSE was measured using the OMNI-RES scale and the load lifted value (kg. To verify the normality of data, the Shapiro-Wilk test was used. Possible differences related to loads and PSE on the platforms were performed by the paired t test. Significance level of p <0.05 was adopted. No significant differences between PSE values on SP and UP were respectively observed in the half squat (8.2 and 8.5 / p = 0.8, pronated barbell row (8.4 and 8.4 / p = 0.7 and biceps curl (8.6 and 8.7 / p = 1.0. Higher load values on SP and UP were respectively found in half squat (83.9kg and 70.3kg / p <0.001 and pronated barbell row exercises (53.2kg and 48.6kg / p = 0.01 on SP. However, biceps curl showed dissimilar behavior (48.2kg and 47.4kg / p = 0.5. It was concluded that UP does not promote differences in PSE responses even working with smaller load or similar load.

  2. FINITE ELEMENT ANALYSIS OF THE BEHAVIOUR OF REINFORCED CONCRETE COLUMNS CONFINED BY OVERLAPPING HOOPS SUBJECTED TO RAPID CONCENTRIC LOADING

    Directory of Open Access Journals (Sweden)

    Xiang Zeng

    2017-12-01

    Full Text Available The strain rate sensitivity of concrete material was discovered approximately one hundred years ago, and it has a marked effect on the behaviour of concrete members subjected to dynamic loadings such as strong earthquake and impact loading. Because of the great importance of the confined reinforced concrete (RC columns in RC structures, the dynamic behaviour of the columns induced by the strain rate effect has been studied, but only few experiments and analyses have been conducted. To investigate the behaviour of overlapping hoop-confined square reinforced normal-strength concrete columns, considering the strain rate effect at a strain rate of 10-5/sec to 10-1/sec induced by earthquake excitation, an explicit dynamic finite element analysis (FEA model was developed in ABAQUS to predict the behaviour of confined RC columns subjected to the rapid concentric loading. A locally modified stress-strain relation of confined concrete with the strain rate sensitivity of the concrete material and the confining effect of overlapping hoops were proposed to complete the simulation of the dynamic behaviour of concrete with the concrete plastic-constitutive model in ABAQUS. The finite element predictions are consistent with the existing test results. Based on the FEA model, a parametric investigation was conducted to capture more information about the behaviour of confined RC columns under varying loading rates.

  3. Performance Evaluation of Waterproofing Membrane Systems Subject to the Concrete Joint Load Behavior of Below-Grade Concrete Structures

    OpenAIRE

    Jaeyoung Song; Kyuhwan Oh; Byoungil Kim; Sangkeun Oh

    2017-01-01

    Below-grade structures such as parking lots, underground subway tunnels, and basements are growing in scale and reaching deeper below-ground levels. In this type of environment, they become subject to higher water pressure. The concrete material of the structures is exposed to wet conditions for longer periods of time, which makes the proper adhesion of waterproofing membranes difficult. Joint movements from increased structural settlement, thermal expansion/shrinkage, and physical loads from...

  4. Dowel-type fastener connections in timber structures subjected to short-term loading

    DEFF Research Database (Denmark)

    Lauritzen Jensen, J.

    Design of dowel-type fastener connections in framed timber structures usually involves a two-step analysis: determination of the distribution of the sectional forces, and design of the eccentrically loaded connections. This report presents an integrated model for design of framed timber structures...

  5. Failure Characteristics of Joint Bolts in Shield Tunnels Subjected to Impact Loads from a Derailed Train

    Directory of Open Access Journals (Sweden)

    Qixiang Yan

    2017-01-01

    Full Text Available Impact loads generated by derailed trains can be extremely high, especially in the case of heavy trains running at high speeds, which usually cause significant safety issues to the rail infrastructures. In shield tunnels, such impact loads may not only cause the damage and deformation of concrete segments, but also lead to the failure of segmental joint bolts. This paper presents a numerical study on the failure behavior of segmental joint bolts in the shield tunnel under impact loading resulting from train derailments. A three-dimensional (3D numerical model of a shield tunnel based on the finite element (FE modelling strategy was established, in which the structural behavior of the segmental joint surfaces and the mechanical behavior of the segmental joint bolts were determined. The numerical results show that the occurrence of bolt failure starts at the joints near the impacted segment and develops along the travel direction of train. An extensive parametric study was subsequently performed and the influences of the bolt failure on the dynamic response of the segment were investigated. In particular, the proposed FE model and the analytical results will be used for optimizing the design method of the shield tunnel in preventing the failure of the joint bolts due to the impact load from a derailed HST.

  6. Effect of cross section on collapse load in pipe bends subjected to in ...

    African Journals Online (AJOL)

    user

    A comparison between pipe bends with assumed cross sections, namely elliptic and semi oval to include ovality along with wall thinning, was performed to determine the plastic collapse load under in-plane closing bending moment using finite element limit analysis based on an elastic-perfectly plastic material considering ...

  7. Design and Evaluation of Composite Fuselage Panels Subjected to Combined Loading Conditions

    Science.gov (United States)

    Ambur, Damodar R.; Rouse, Marshall

    1998-01-01

    Methodologies used in industry for designing transport aircraft composite fuselage structures are discussed. Several aspects of the design methodologies are based on assumptions from metallic fuselage technology which requires that full-scale structures be tested with the actual loading conditions to validate the designs. Composite panels which represent crown and side regions of a fuselage structure are designed using this approach and tested in biaxial tension. Descriptions of the state-of-the-art test facilities used for this structural evaluation are presented. These facilities include a pressure-box test machine and a D-box test fixture in a combined loads test machine which are part of a Combined Loads Test System (COLTS). Nonlinear analysis results for a reference shell and a stiffened composite panel tested in the pressure-box test machine with and without damage are presented. The analytical and test results are compared to assess the ability of the pressure-box test machine to simulate a shell stress state with and without damage. A combined loads test machine for testing aircraft primary structures is described. This test machine includes a D-box test fixture to accommodate curved stiffened panels and the design features of this test fixture are presented. Finite element analysis results for a curved panel to be tested in the D-box test fixture are also discussed.

  8. A Study on the Transient Response of a Stepped Column Subjected to an Impact Load

    Science.gov (United States)

    2004-06-01

    buckling load of the model 1. Therefore, from the figure, we know that the stresses of all models exceed the ultimate tensile strength of Al2024 -t3, 45...reduced to 75% than that of model 1, and the stress values are exceeding the ultimate tensile strength of an Al2024 -t3, 45kg/mm2. Table 4 is

  9. Dynamic behaviour of mono bucket foundations subjected to combined transient loading

    DEFF Research Database (Denmark)

    Nielsen, Søren Dam; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl

    2015-01-01

    This article presents the results from small scale testing, investigating the effect of transient combined loading of a bucketfoundation. The tests are performed inside a pressure tank at Aalborg University, Denmark. The bucket foundation was installed in dense water saturated sand and transient ...

  10. Duration of load behaviour of different sized straight timber beams subjected to bending in variable climate

    DEFF Research Database (Denmark)

    Hanhijärvi, A.; Galimard, P.; Hoffmeyer, Preben

    1998-01-01

    The paper is the second in a series which sums up the results of an extensive project to quantify the duration-of-load (DOL) effect on different sized timber beams in different climates. The paper deals with straight (unnotched) beams. The results of various DOL-tests of stepwise and constant...

  11. Simulations under uncertainty for occupant safety for a vehicle subjected to a blast load

    NARCIS (Netherlands)

    Sun, J.; Vlahopoulos, N.; Stabryla, T.J.; Goetz, R.; Velde, R. van de

    2006-01-01

    One of the main threats to military vehicles originates from landmine blasts. In order to improve the survivability of the occupants it is important to design a military vehicle for increased occupant safety. Simulation technology that combines modeling of the blast loads from the landmine

  12. 34 CFR 97.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Research undertaken without the intention of involving... Protection of Human Research Subjects) § 97.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is...

  13. Three-Dimensional Dynamic Analyses of Track-Embankment-Ground System Subjected to High Speed Train Loads

    Science.gov (United States)

    2014-01-01

    A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed. PMID:24723838

  14. Three-dimensional dynamic analyses of track-embankment-ground system subjected to high speed train loads.

    Science.gov (United States)

    Fu, Qiang; Zheng, Changjie

    2014-01-01

    A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.

  15. Three-Dimensional Dynamic Analyses of Track-Embankment-Ground System Subjected to High Speed Train Loads

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2014-01-01

    Full Text Available A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.

  16. Dynamic analysis of slab track on multi-layered transversely isotropic saturated soils subjected to train loads

    Science.gov (United States)

    Zhan, Yongxiang; Yao, Hailin; Lu, Zheng; Yu, Dongming

    2014-12-01

    The dynamic responses of a slab track on transversely isotropic saturated soils subjected to moving train loads are investigated by a semi-analytical approach. The track model is described as an upper Euler beam to simulate the rails and a lower Euler beam to model the slab. Rail pads between the rails and slab are represented by a continuous layer of springs and dashpots. A series of point loads are formulated to describe the moving train loads. The governing equations of track-ground systems are solved using the double Fourier transform, and the dynamic responses in the time domain are obtained by the inverse Fourier transform. The results show that a train load with high velocity will generate a larger response in transversely isotropic saturated soil than the lower velocity load, and special attention should be paid on the pore pressure in the vicinity of the ground surface. The anisotropic parameters of a surface soil layer will have greater influence on the displacement and excess pore water pressure than those of the subsoil layer. The traditional design method taking ground soil as homogeneous isotropic soil is unsafe for the case of RE < 1 and RG < 1, so a transversely isotropic foundation model is of great significance to the design for high train velocities.

  17. A Justification for Subjectivity in Art Education Research.

    Science.gov (United States)

    Fielding, Rob

    1996-01-01

    Highlights some of the fundamental differences between positivistic and qualitative research methods regarding art education. Defends qualitative research and argues that applying natural science research principles to human endeavors is often futile. Discusses the special problems and advantages of qualitative research. (MJP)

  18. Fatigue damage accumulation and lifetime prediction of defective C35 steel subjected to block loading

    Directory of Open Access Journals (Sweden)

    Sallem Haifa

    2014-06-01

    Full Text Available This paper deals with the influence of both defect and loading sequence on fatigue damage accumulation of C35 steel containing artificial defects. Tests were carried out using fatigue samples with artificial spherical defects introduced at the surface. Tests were performed using two blocks loading under increasing and decreasing magnitude. The experimental results were compared to the damage calculated by the Miner rule. In the case of defective material; it is shown in both cases a minor influence of sequence’s effect. A lifetime prediction method is then developed to assess the residual lifetime of damaged defective material. The method is based on a multiaxial endurance criterion used to calculate the equivalent local stress distribution around the defect and to inject it in an uniaxial damage cumulative rule. Finally a comparison between experimental and theoretical results is performed. It is observed that the Mesmacque sequential law gives the most accurate lifetime prediction of defective specimens.

  19. Dynamic Evaluation of Acrylonitrile Butadiene Styrene Subjected to High-Strain-Rate Compressive Loads

    Science.gov (United States)

    2014-12-01

    Conclusions 10 5. References 11 Distribution List 13 iv List of Figures Figure 1. ASTM D 638-03 dog bone...1. ASTM D 638-03 dog bone. When designing the specimen for tensile testing, it is important that the tensile specimen be built such that the...2006, 45 (1), 18–24. 8. Lee, W. S.; Lin, C. F. Plastic Deformation and Fracture Behaviour of Ti–6Al–4V Alloy Loaded With High Strain Rate Under

  20. Reducing Structural Weight and Increasing Protection in Simple Structures Subjected to Blast Loads

    Science.gov (United States)

    2014-08-12

    compression measured in the spring, which is determined from the governing equations shown in Appendix A. In the LS-DYNA model, a single spring- mass - damper ...like a solid when experiencing a large shear load, such as an impulse of high pressure but of short duration from a blast, and returns to liquid ... mass model with a single degree of freedom (DOF) representing the upper torso of the occupant (Appendix A) is mounted directly in the middle of the

  1. Numerical Behavior Reproduction of a Truss Structure and Beam, Subjected to Concentrated Load

    Directory of Open Access Journals (Sweden)

    Nedelcu Dorian

    2010-10-01

    Full Text Available The paper deals with a numerical reproduction of a real experiment consisting of the same restraints and concentrated load applied to a truss structure and beam; the numerical reproduction was performed with SolidWorks software, where both geometrical reconstruction and finite element analysis were made. The goals of the analysis was to compare the numerical with experimental results and to evaluate the best structure using the structural response criteria.

  2. Parametric Study of Square Concrete Filled Steel Tube Columns Subjected To Concentric Loading

    OpenAIRE

    Bhushan H. Patil; P. M. Mohite

    2014-01-01

    The Concrete Filled Steel Tube (CFST) member has many advantages compared with the conventional concrete structural member. This study presents on the behaviour of concrete-filled steel tube (CFST) columns under axial load by changing parameters. The parameters are thickness of steel tube, Grade of concrete and length of column. The study was conducted using ANSYS 13 finite element software. All the columns are 60 X 60 mm in size. The thickness of the tube is taken as 2, 3, 4, ...

  3. Stresses and Strains in Plain and Coldworked Annuli Subjected to Remote, Interference or Combined Loading

    Science.gov (United States)

    1992-05-01

    Australian Airlines, Library Qantas Airways Limited Civil Aviation Authority Hawker de Havilland Aust Pty Ltd, Victoria, Library Hawker de Havilland Aust Pty...of the annulus from the pin, (34): yielding of the resulting open hole annulus (13) provides the positive stress limit of elastic behaviour shown...curves in Figs. 11 and 12. It is seen that, under either tensile or compressive loading, the stress limits are identical in the region from the bore to the

  4. Experimental study on lateral strength of wall-slab joint subjected to lateral cyclic load

    Science.gov (United States)

    Masrom, Mohd Asha'ari; Mohamad, Mohd Elfie; Hamid, Nor Hayati Abdul; Yusuff, Amer

    2017-10-01

    Tunnel form building has been utilised in building construction since 1960 in Malaysia. This method of construction has been applied extensively in the construction of high rise residential house (multistory building) such as condominium and apartment. Most of the tunnel form buildings have been designed according to British standard (BS) whereby there is no provision for seismic loading. The high-rise tunnel form buildings are vulnerable to seismic loading. The connections between slab and shear walls in the tunnel-form building constitute an essential link in the lateral load resisting mechanism. Malaysia is undergoing a shifting process from BS code to Eurocode (EC) for building construction since the country has realised the safety threats of earthquake. Hence, this study is intended to compare the performance of the interior wall slab joint for a tunnel form structure designed based on Euro and British codes. The experiment included a full scale test of the wall slab joint sub-assemblages under reversible lateral cyclic loading. Two sub-assemblage specimens of the wall slab joint were designed and constructed based on both codes. Each specimen was tested using lateral displacement control (drift control). The specimen designed by using Eurocode was found could survive up to 3.0% drift while BS specimen could last to 1.5% drift. The analysis results indicated that the BS specimen was governed by brittle failure modes with Ductility Class Low (DCL) while the EC specimen behaved in a ductile manner with Ductility Class Medium (DCM). The low ductility recorded in BS specimen was resulted from insufficient reinforcement provided in the BS code specimen. Consequently, the BS specimen could not absorb energy efficiently (low energy dissipation) and further sustain under inelastic deformation.

  5. Experimental Tests on the Composite Foam Sandwich Pipes Subjected to Axial Load

    Science.gov (United States)

    Li, Feng; Zhao, QiLin; Xu, Kang; Zhang, DongDong

    2015-12-01

    Compared to the composite thin-walled tube, the composite foam sandwich pipe has better local flexural rigidity, which can take full advantage of the high strength of composite materials. In this paper, a series of composite foam sandwich pipes with different parameters were designed and manufactured using the prefabricated polyurethane foam core-skin co-curing molding technique with E-glass fabric prepreg. The corresponding axial-load compressive tests were conducted to investigate the influence factors that experimentally determine the axial compressive performances of the tubes. In the tests, the detailed failure process and the corresponding load-displacement characteristics were obtained; the influence rules of the foam core density, surface layer thickness, fiber ply combination and end restraint on the failure modes and ultimate bearing capacity were studied. Results indicated that: (1) the fiber ply combination, surface layer thickness and end restraint have a great influence on the ultimate load bearing capacity; (2) a reasonable fiber ply combination and reliable interfacial adhesion not only optimize the strength but also transform the failure mode from brittle failure to ductile failure, which is vital to the fully utilization of the composite strength of these composite foam sandwich pipes.

  6. Tow-Steered Panels With Holes Subjected to Compression or Shear Loads

    Science.gov (United States)

    Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer

    2005-01-01

    Tailoring composite laminates to vary the fiber orientations within a fiber layer of a laminate to address non-uniform stress states and provide structural advantages such as the alteration of principal load paths has potential application to future low-cost, light-weight structures for commercial transport aircraft. Evaluation of this approach requires the determination of the effectiveness of stiffness tailoring through the use of curvilinear fiber paths in flat panels including the reduction of stress concentrations around the holes and the increase in load carrying capability. Panels were designed through the use of an optimization code using a genetic algorithm and fabricated using a tow-steering approach. Manufacturing limitations, such as the radius of curvature of tows the machine could support, avoidance of wrinkling of fibers and minimization of gaps between fibers were considered in the design process. Variable stiffness tow-steered panels constructed with curvilinear fiber paths were fabricated so that the design methodology could be verified through experimentation. Finite element analysis where each element s stacking sequence was accurately defined is used to verify the behavior predicted based on the design code. Experiments on variable stiffness flat panels with central circular holes were conducted with the panels loaded in axial compression or shear. Tape and tow-steered panels are used to demonstrate the buckling, post-buckling and failure behavior of elastically tailored panels. The experimental results presented establish the buckling performance improvements attainable by elastic tailoring of composite laminates.

  7. Hybrid Element Method for Compsoite Structures Subjected to Boundary Layer Loading Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In many situations, aerospace structures are subjected to a wide frequency spectrum of mechanical and/or acoustic excitations and therefore, there is a need for the...

  8. The response of pile-guided floats subjected to dynamic loading : volume II annex.

    Science.gov (United States)

    2014-08-01

    Pile-Guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to dynamic : forces such as wind generated waves and impacts from vessels. This project developed a rational basis for esti...

  9. The response of pile-guided floats subjected to dynamic loading.

    Science.gov (United States)

    2014-08-01

    Pile-Guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to dynamic : forces such as wind generated waves and impacts from vessels. This project developed a rational basis for esti...

  10. Rethinking the Subject of Higher Education: Subjectivity, Normativity and Desire in Student Equity Research

    Science.gov (United States)

    Devos, Anita

    2012-01-01

    In this paper, I reflect on three questions arising from my recent research on student equity in higher education and gender in education. These questions relate to the goals, focus and politics of student equity research in the context of a changing higher education landscape in Australia. The paper concludes with an argument for student equity…

  11. Cognitive load theory, educational research, and instructional design; some food for thought

    OpenAIRE

    de Jong, Anthonius J.M.

    2010-01-01

    Cognitive load is a theoretical notion with an increasingly central role in the educational research literature. The basic idea of cognitive load theory is that cognitive capacity in working memory is limited, so that if a learning task requires too much capacity, learning will be hampered. The recommended remedy is to design instructional systems that optimize the use of working memory capacity and avoid cognitive overload. Cognitive load theory has advanced educational research considerably...

  12. 75 FR 57469 - Guidance on Withdrawal of Subjects From Research: Data Retention and Other Related Issues

    Science.gov (United States)

    2010-09-21

    ... HUMAN SERVICES Guidance on Withdrawal of Subjects From Research: Data Retention and Other Related Issues... availability of a guidance document entitled, ``Guidance on Withdrawal of Subjects From Research: Data... guidance document entitled, ``Guidance on Withdrawal of Subjects From Research: Data Retention and Other...

  13. 45 CFR 46.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Research undertaken without the intention of... Subjects § 46.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is later proposed to...

  14. 32 CFR 219.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Research undertaken without the intention of... undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is later proposed to involve human subjects in the research...

  15. 49 CFR 11.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Research undertaken without the intention of... PROTECTION OF HUMAN SUBJECTS § 11.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is...

  16. 28 CFR 46.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Research undertaken without the intention... (CONTINUED) PROTECTION OF HUMAN SUBJECTS § 46.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects...

  17. 16 CFR 1028.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Research undertaken without the intention of... GENERAL PROTECTION OF HUMAN SUBJECTS § 1028.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects...

  18. 7 CFR 1c.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Research undertaken without the intention of involving... HUMAN SUBJECTS § 1c.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is later proposed...

  19. 22 CFR 225.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Research undertaken without the intention of... PROTECTION OF HUMAN SUBJECTS § 225.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is...

  20. 40 CFR 26.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-07-01

    ... intention of involving human subjects. 26.119 Section 26.119 Protection of Environment ENVIRONMENTAL... Research Conducted or Supported by EPA § 26.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects...

  1. Experimental studies on the deformation and rupture of thin metal plates subject to underwater shock wave loading

    Directory of Open Access Journals (Sweden)

    Chen Pengwan

    2015-01-01

    Full Text Available In this paper, the dynamic deformation and rupture of thin metal plates subject to underwater shock wave loading are studied by using high-speed 3D digital image correlation (3D-DIC. An equivalent device consist of a gas gun and a water anvil tube was used to supplying an exponentially decaying pressure in lieu of explosive detonation which acted on the panel specimen. The thin metal plate is clamped on the end of the shock tube by a flange. The deformation and rupture process of the metal plates subject to underwater shock waves are recorded by two high-speed cameras. The shape, displacement fields and strain fields of the metal plates under dynamic loading are obtained by using VIC-3D digital image correlation software. The strain gauges also were used to monitor the structural response on the selected position for comparison. The DIC data and the strain gauges results show a high level of correlation, and 3D-DIC is proven to be an effective method to measure 3D full-field dynamic response of structures under underwater impact loading. The effects of pre-notches on the failure modes of thin circular plate were also discussed.

  2. Edge delamination of composite laminates subject to combined tension and torsional loading

    Science.gov (United States)

    Hooper, Steven J.

    1990-01-01

    Delamination is a common failure mode of laminated composite materials. Edge delamination is important since it results in reduced stiffness and strength of the laminate. The tension/torsion load condition is of particular significance to the structural integrity of composite helicopter rotor systems. Material coupons can easily be tested under this type of loading in servo-hydraulic tension/torsion test stands using techniques very similar to those used for the Edge Delamination Tensile Test (EDT) delamination specimen. Edge delamination of specimens loaded in tension was successfully analyzed by several investigators using both classical laminate theory and quasi-three dimensional (Q3D) finite element techniques. The former analysis technique can be used to predict the total strain energy release rate, while the latter technique enables the calculation of the mixed-mode strain energy release rates. The Q3D analysis is very efficient since it produces a three-dimensional solution to a two-dimensional domain. A computer program was developed which generates PATRAN commands to generate the finite element model. PATRAN is a pre- and post-processor which is commonly used with a variety of finite element programs such as MCS/NASTRAN. The program creates a sufficiently dense mesh at the delamination crack tips to support a mixed-mode fracture mechanics analysis. The program creates a coarse mesh in those regions where the gradients in the stress field are low (away from the delamination regions). A transition mesh is defined between these regions. This program is capable of generating a mesh for an arbitrarily oriented matrix crack. This program significantly reduces the modeling time required to generate these finite element meshes, thus providing a realistic tool with which to investigate the tension torsion problem.

  3. Do the rotator cuff tendons of young athletic subjects hypertrophy in response to increased loading demands?

    Science.gov (United States)

    Milgrom, Charles; Moran, Daniel S; Safran, Ori; Finsestone, Aharon S

    2012-11-01

    The rotator cuff is composed of muscle and tendon units. Although muscle has been shown to adapt to mechanical loads, the response of human tendon is not well defined. We hypothesized that increased loading demands on the rotator cuff of young trainees would cause an adaptive muscle response but not an adaptive hypertrophic tendon response. The hypertrophic response of the rotator cuff tendon, shoulder strength, aerobic fitness, and the lean body weight of 70 young male recruits were studied before and after a 1-year course of elite infantry training. Shoulder strength was assessed by the maximum number of pull-ups done and the rotator cuff thickness by ultrasound measurement of the supraspinatus thickness. Aerobic physical fitness was assessed by maximum oxygen consumption (Vo(2) max). Lean body weight was measured by skin-fold thickness. The mean number of pull-ups done increased from 17.5 to 21.7 (P = .01), but the supraspinatus thickness at the beginning of training (6.1 mm) was unchanged at the end of the training. Vo(2) max increased from 57 to 64 mL/kg/min (P = .0001). Lean body weight increased from 58.3 to 64.7 kg (P = .0001). As a result of increased loading, the strength of the rotator cuff muscles of young trainees increased, but by the parameter of hypertrophy, no evidence was found of a parallel adaptive response of the rotator cuff tendon. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  4. Initiation of Failure for Masonry Subject to In-Plane Loads through Micromechanics

    Directory of Open Access Journals (Sweden)

    V. P. Berardi

    2016-01-01

    Full Text Available A micromechanical procedure is used in order to evaluate the initiation of damage and failure of masonry with in-plane loads. Masonry material is viewed as a composite with periodic microstructure and, therefore, a unit cell with suitable boundary conditions is assumed as a representative volume element of the masonry. The finite element method is used to determine the average stress on the unit cell corresponding to a given average strain prescribed on the unit cell. Finally, critical curves representing the initiation of damage and failure in both clay brick masonry and adobe masonry are provided.

  5. Dowel-type fastener connections in timber structures subjected to short-term loading

    DEFF Research Database (Denmark)

    Lauritzen Jensen, J.

    Design of dowel-type fastener connections in framed timber structures usually involves a two-step analysis: determination of the distribution of the sectional forces, and design of the eccentrically loaded connections. This report presents an integrated model for design of framed timber structures...... with dowel-type fastener connections. A Finite-Element approach has been adopted. An element has been developed for modelling a plane group of dowel-type fasteners, taking due account of the material and geometric non-linearities, and two different elements have been developed for modelling gap closure...

  6. Subject-specific geometrical detail rather than cost function formulation affects hip loading calculation.

    Science.gov (United States)

    Wesseling, Mariska; De Groote, Friedl; Bosmans, Lode; Bartels, Ward; Meyer, Christophe; Desloovere, Kaat; Jonkers, Ilse

    2016-11-01

    This study assessed the relative importance of introducing an increasing level of medical image-based subject-specific detail in bone and muscle geometry in the musculoskeletal model, on calculated hip contact forces during gait. These forces were compared to introducing minimization of hip contact forces in the optimization criterion. With an increasing level of subject-specific detail, specifically MRI-based geometry and wrapping surfaces representing the hip capsule, hip contact forces decreased and were more comparable to contact forces measured using instrumented prostheses (average difference of 0.69 BW at the first peak compared to 1.04 BW for the generic model). Inclusion of subject-specific wrapping surfaces in the model had a greater effect than altering the cost function definition.

  7. Response of a circular steel plate with different weld geometries subject to impact loading

    Directory of Open Access Journals (Sweden)

    Meyer L.W.

    2012-08-01

    Full Text Available The dynamic response of clamped circular steel plates was experimentally investigated under impact loading. The experiments were performed using a high energy drop weight machine with a 5 ton drop weight, which falls from a height of 0.8 m and results in a total impact energy of 40 kJ. Target plates of 10 mm thickness and 580 mm diameter were welded in three different geometrical configurations of weld elements on the lower side. The impact process was carried out using a hemispherical punch. The force was registered by strain gages on the punch. A full dynamic strain field measurement was applied on the tension side using two high speed cameras. The evaluation of the strain field was carried out with the speckle photography technique. The effect of cracks and welding on the deformation and failure behavior was studied using pre-cracked disks and plates with welded webs, welded circular discs and also with a weld seam only. The failure of the plates was registered using the high speed cameras and from the force signal. The results are analyzed and discussed regarding the behavior of the material and component under high rate loading.

  8. Parametric Study of Single Bolted Composite Bolted Joint Subjected to Static Tensile Loading

    Science.gov (United States)

    Awadhani, L. V.; Bewoor, Anand, Dr.

    2017-08-01

    The use of composites is increasing in the engineering applications in order to reduce the weight, building energy efficient systems, designing a suitable material according to the requirements of the application. But at the same time, building a structure is possible only by bonding or bolting or combination of them. There are limitations for the bonding methods and problems with the bolting such as stress concentration near the neighborhood of the bolt hole, tensile or shear failure, delamination etc. Hence the design of a composite bolted structure needs a special attention. This paper focuses on the performance of the composite bolted joint under static tensile loading and the effect of variation in the parameters such as the bolt pitch, plate width, thickness, bolt tightening torque, composite material, coefficient of friction between the bolt and plate etc. A simple spring mass model is used to study the single bolted composite bolted joint. The influencing parameters are identified through the developed model and compared with the results from the literature. The best geometric parameters for the applied load are identified for the composite bolted joints.

  9. Spatially varying small-strain stiffness in soils subjected to K0 loading

    KAUST Repository

    Kim, Hyun-Ki

    2017-08-08

    Grain-scale characteristics and formation history determine spatial variability in granular masses. We investigate the effect of spatially varying stiffness on the load-deformation response under zero-lateral strain conditions using numerical simulations of correlated random fields, where the granular medium is represented by a non-linear stress-dependent meso-scale model. Results show that stiffness heterogeneity results in higher global compressibility as compared to the homogeneous medium with the same arithmetic mean stiffness. Furthermore, the non-homogeneous stress field that develops inside the granular mass is characterized by focused load transfer along columnar regions, higher stress anisotropy and lower horizontal-to-vertical stress ratio K0 than in a granular medium of homogenous stiffness. As the applied stress increases, the inherent stress-dependent response of the granular material leads to a more homogenous stress field. While greater variance in stiffness causes lower global stiffness, a longer correlation length results in greater variance in global mechanical response among multiple realizations.

  10. Analysis of rockburst in tunnels subjected to static and dynamic loads

    Directory of Open Access Journals (Sweden)

    Amin Manouchehrian

    2017-12-01

    Full Text Available The presence of geological structures such as faults, joints, and dykes has been observed near excavation boundaries in many rockburst case histories. In this paper, the role of discontinuities around tunnels in rockburst occurrence was studied. For this purpose, the Abaqus explicit code was used to simulate dynamic rock failure in deep tunnels. Material heterogeneity was considered using Python scripting in Abaqus. Rockbursts near fault regions in deep tunnels under static and dynamic loads were studied. Several tunnel models with and without faults were built and static and dynamic loads were used to simulate rock failure. The velocity and the released kinetic energy of failed rocks, the failure zone around the tunnel, and the deformed mesh were studied to identify stable and unstable rock failures. Compared with models without discontinuities, the results showed that the velocity and the released kinetic energy of failed rocks were higher, the failure zone around the tunnel was larger, and the mesh was more deformed in the models with discontinuities, indicating that rock failure in the models with discontinuities was more violent. The modeling results confirm that the presence of geological structures in the vicinity of deep excavations could be one of the major influence factors for the occurrence of rockburst. It can explain localized rockburst occurrence in civil tunnels and mining drifts. The presented methodology in this paper for rockburst analysis can be useful for rockburst anticipation and control during mining and tunneling in highly stressed ground.

  11. Experimental investigation on the dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loadings

    Science.gov (United States)

    Huang, Wei; Zhang, Wei; Li, Dacheng; Hypervelocity Impact Research Center Team

    2015-06-01

    Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of solid monolithic plates and corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick and 10mm-thick 3003 aluminum corrugated core and 5A06 face sheets are compared with the 5A06 solid monolithic plates in this paper. The dynamic deformation of plates are captured with the the 3D digital speckle correlation method (DIC). The results affirm that sandwich structures show a 30% reduction in the maximum plate deflection compare with a monolithic plate of identical mass per unit area, and the peak value of deflection effectively reduced by increasing the thickness core. The failure modes of sandwich plates consists of core crushing, imprinting, stretch tearing of face sheets, bending and permanent deformation of entire structure with the increasing impulsive loads, and the failure mechanisms are analyzed with the postmortem panels and dynamic deflection history captured by cameras. National Natural Science Foundation of China (NO.: 11372088).

  12. Behavioral obesity research: Where have all the single subjects gone?

    OpenAIRE

    Anderson, Jean E.; Gross, Alan M.

    1988-01-01

    Many recent reviews of the literature concerning behavioral treatments of obesity have concluded that behavioral methods have not been as successful in treating this problem as might have been predicted in the early years of behavior modification. Among the many potential reasons for this lack of success is the growing trend to utilize group statistical designs rather than single subject designs to examine the problem of obesity, in spite of the fact that single case methodology has provided ...

  13. Buckling behaviors of cantilevered open-tip carbon nanocones subjected to transverse loading: A molecular dynamics study

    Science.gov (United States)

    Liao, Ming-Liang

    2017-11-01

    This study used molecular dynamics simulations to investigate buckling behaviors of cantilevered open-tip carbon nanocones (CNCs) subjected to transverse loading. Some interesting findings were attained in the study. The critical angles of the CNCs were observed to decrease with increases in the temperature, cone length, top diameter, and apex angle of the CNCs. While the critical loads of the CNCs were found to decrease with increasing temperature and cone length, they were noted to increase with enlargement of the top diameter and apex angle. The observed temperature effects were more evident as the cone length increased. In addition, each of the studied CNCs exhibited a near-bottom-indented buckling morphology at the examined temperatures, which is quite different from a top-center-indented buckling morphology of an open-tip CNC under pure bending. Accordingly, these results may provide beneficial information to the designs of ultra-sensitive mass detectors using CNCs.

  14. Experimental investigation of interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J.H.; Berggreen, Christian

    2017-01-01

    A recently proposed face-sheet–core interface crack arresting device is implemented in sandwich beams and tested using the Sandwich Tear Test configuration. Fatigue loading conditions are applied to propagate the crack and determine the effect of the crack stopper on the fatigue growth rate...... and arrest of the crack. Digital image correlation is used through the duration of the fatigue experiment to track the strain evolution as the crack tip advances. The measured strains are related to crack tip propagation, arrest, and re-initiation of the crack. A finite element model is used to calculate...... the energy release rate, mode mixity and to simulate crack propagation and arrest of the crack. Finally, the effectiveness of the crack arresting device is demonstrated on composite sandwich beams subjected to fatigue loading conditions....

  15. Assessment of Masonry Buildings Subjected to Landslide-Induced Settlements: From Load Path Method to Evolutionary Optimization Method

    Science.gov (United States)

    Palmisano, Fabrizio; Elia, Angelo

    2017-10-01

    One of the main difficulties, when dealing with landslide structural vulnerability, is the diagnosis of the causes of crack patterns. This is also due to the excessive complexity of models based on classical structural mechanics that makes them inappropriate especially when there is the necessity to perform a rapid vulnerability assessment at the territorial scale. This is why, a new approach, based on a ‘simple model’ (i.e. the Load Path Method, LPM), has been proposed by Palmisano and Elia for the interpretation of the behaviour of masonry buildings subjected to landslide-induced settlements. However, the LPM is very useful for rapidly finding the 'most plausible solution' instead of the exact solution. To find the solution, optimization algorithms are necessary. In this scenario, this article aims to show how the Bidirectional Evolutionary Structural Optimization method by Huang and Xie, can be very useful to optimize the strut-and-tie models obtained by using the Load Path Method.

  16. Numerical Analysis of Dynamic Response of Corrugated Core Sandwich Panels Subjected to Near-Field Air Blast Loading

    Directory of Open Access Journals (Sweden)

    Pan Zhang

    2014-01-01

    Full Text Available Three-dimensional fully coupled simulation is conducted to analyze the dynamic response of sandwich panels comprising equal thicknesses face sheets sandwiching a corrugated core when subjected to localized impulse created by the detonation of cylindrical explosive. A large number of computational cases have been calculated to comprehensively investigate the performance of sandwich panels under near-field air blast loading. Results show that the deformation/failure modes of panels depend strongly on stand-off distance. The beneficial FSI effect can be enhanced by decreasing the thickness of front face sheet. The core configuration has a negligible influence on the peak reflected pressure, but it has an effect on the deflection of a panel. It is found that the benefits of a sandwich panel over an equivalent weight solid plate to withstand near-field air blast loading are more evident at lower stand-off distance.

  17. Salt loading affects cortisol metabolism in normotensive subjects : Relationships with salt sensitivity

    NARCIS (Netherlands)

    Kerstens, MN; van der Kleij, FGH; Boonstra, AH; Sluiter, WJ; Koerts, J; Navis, G; Dullaart, RPF

    We studied cortisol metabolism together with insulin sensitivity [homeostatic model assessment (HOMA)] and renal hemodynamics in 19 salt-resistant (sr) and nine salt-sensitive ( ss) normotensive subjects after a low-and high-salt diet. Results are described as high- vs. low-salt diet. Sum of urinary

  18. Biomechanics of volunteers subject to loading by a motorized shoulder belt tensioner.

    Science.gov (United States)

    Good, Craig A; Viano, David C; Ronsky, Janet L

    2008-04-15

    A biomechanical study using human volunteers. Motorized shoulder belt tensioning is a new seatbelt technology that is likely to be incorporated into future vehicles. The objective of this study was to characterize the upper torso biomechanics of 3 sizes of adult volunteers (5th percentile female, 50th percentile male, and 95th percentile male) subjected to motorized shoulder belt tensioning in the static environment. There is a lack of volunteer data concerning the biomechanics of occupants subject to motorized precrash shoulder belt tensioning. Studies of torso repositioning by the air force for ejection seats are much too aggressive to be relevant to motorized systems. Low-level motorized shoulder belt tensioning is well tolerated by vehicle occupants but optimized performance by occupant size is unknown. Nineteen male and 6 female subjects were instrumented in a fixture designed to support the occupant leaning forward and apply seatbelt tension. The subjects were 5th percentile females, 50th percentile males, and 95th percentile males. Reflective markers were placed on the subjects to monitor torso kinematics during tensioning. Changes in spinal curvature were small during shoulder belt tensioning and the angular motion of the torso originated within 4.2 cm of the pelvis-femur junction or H-point. Torso repositioning and retraction timing was found to be: 54.3 degrees in 0.78 seconds for the 5th percentile female, 57.6 degrees in 0.95 seconds for the 50th percentile male, and 42.2 degrees in 0.92 seconds for the 95th percentile male. Occupant size has a significant effect on retraction time to reposition the torso during shoulder belt tensioning. Larger vehicle occupants require more time because of a slower retraction velocity. The results are sufficiently simple that a lumped-mass model can predict tensioning kinetics.

  19. Unsaturated Oral Fat Load Test Improves Glycemia, Insulinemia and Oxidative Stress Status in Nondiabetic Subjects with Abdominal Obesity.

    Science.gov (United States)

    Martinez-Hervas, Sergio; Navarro, Inmaculada; Real, Jose T; Artero, Ana; Peiro, Marta; Gonzalez-Navarro, Herminia; Carmena, Rafael; Ascaso, Juan F

    2016-01-01

    To evaluate the changes in glycemia, insulinemia, and oxidative stress markers during an oral fat load test in nondiabetic subjects with abdominal obesity and to analyze the association between postprandial oxidative stress markers and postprandial glucose and insulin responses. We included 20 subjects with abdominal obesity (waist circumference > 102 cm for men and > 88 cm for women) and 20 healthy lean controls (waist circumference < 102 cm for men and < 88 cm for women). After 12 hours of fasting we performed a standardized fat load test (0-8 hours) with supracal® (50 g/m2). We determined metabolic parameters, oxidized and reduced glutathione, and malondialdehyde. In both groups, insulin, HOMA, oxidized/reduced glutathione ratio, and malondialdehyde significantly decreased in the postprandial state after the OFLT. All these parameters were significantly higher in the abdominal obesity group at baseline and during all the postprandial points, but the reduction from the baseline levels was significantly higher in the abdominal obesity group. Unsaturated fat improves insulin resistance and oxidative stress status. It is possible that a consumption of unsaturated fat could be beneficial even in subjects with abdominal obesity in postprandial state.

  20. Unsaturated Oral Fat Load Test Improves Glycemia, Insulinemia and Oxidative Stress Status in Nondiabetic Subjects with Abdominal Obesity.

    Directory of Open Access Journals (Sweden)

    Sergio Martinez-Hervas

    Full Text Available To evaluate the changes in glycemia, insulinemia, and oxidative stress markers during an oral fat load test in nondiabetic subjects with abdominal obesity and to analyze the association between postprandial oxidative stress markers and postprandial glucose and insulin responses.We included 20 subjects with abdominal obesity (waist circumference > 102 cm for men and > 88 cm for women and 20 healthy lean controls (waist circumference < 102 cm for men and < 88 cm for women. After 12 hours of fasting we performed a standardized fat load test (0-8 hours with supracal® (50 g/m2. We determined metabolic parameters, oxidized and reduced glutathione, and malondialdehyde.In both groups, insulin, HOMA, oxidized/reduced glutathione ratio, and malondialdehyde significantly decreased in the postprandial state after the OFLT. All these parameters were significantly higher in the abdominal obesity group at baseline and during all the postprandial points, but the reduction from the baseline levels was significantly higher in the abdominal obesity group.Unsaturated fat improves insulin resistance and oxidative stress status. It is possible that a consumption of unsaturated fat could be beneficial even in subjects with abdominal obesity in postprandial state.

  1. Prediction of the structural response of the femoral shaft under dynamic loading using subject-specific finite element models.

    Science.gov (United States)

    Park, Gwansik; Kim, Taewung; Forman, Jason; Panzer, Matthew B; Crandall, Jeff R

    2017-08-01

    The goal of this study was to predict the structural response of the femoral shaft under dynamic loading conditions using subject-specific finite element (SS-FE) models and to evaluate the prediction accuracy of the models in relation to the model complexity. In total, SS-FE models of 31 femur specimens were developed. Using those models, dynamic three-point bending and combined loading tests (bending with four different levels of axial compression) of bare femurs were simulated, and the prediction capabilities of five different levels of model complexity were evaluated based on the impact force time histories: baseline, mass-based scaled, structure-based scaled, geometric SS-FE, and heterogenized SS-FE models. Among the five levels of model complexity, the geometric SS-FE and the heterogenized SS-FE models showed statistically significant improvement on response prediction capability compared to the other model formulations whereas the difference between two SS-FE models was negligible. This result indicated the geometric SS-FE models, containing detailed geometric information from CT images with homogeneous linear isotropic elastic material properties, would be an optimal model complexity for prediction of structural response of the femoral shafts under the dynamic loading conditions. The average and the standard deviation of the RMS errors of the geometric SS-FE models for all the 31 cases was 0.46 kN and 0.66 kN, respectively. This study highlights the contribution of geometric variability on the structural response variation of the femoral shafts subjected to dynamic loading condition and the potential of geometric SS-FE models to capture the structural response variation of the femoral shafts.

  2. Research Based on AMESim of Electro-hydraulic Servo Loading System

    Science.gov (United States)

    Li, Jinlong; Hu, Zhiyong

    2017-09-01

    Electro-hydraulic servo loading system is a subject studied by many scholars in the field of simulation and control at home and abroad. The electro-hydraulic servo loading system is a loading device simulation of stress objects by aerodynamic moment and other force in the process of movement, its function is all kinds of gas in the lab condition to analyze stress under dynamic load of objects. The purpose of this paper is the design of AMESim electro-hydraulic servo system, PID control technology is used to configure the parameters of the control system, complete the loading process under different conditions, the optimal design parameters, optimization of dynamic performance of the loading system.

  3. In Europe, hooligans are prime subjects for research.

    Science.gov (United States)

    Hagmann, M

    2000-07-28

    CAMBRIDGE, U.K.--One of the few burgeoning areas of violence research here and in Europe is football hooliganism. With lower homicide rates than in the United States and fewer incidences of killing sprees such as the Littleton school shooting, Europeans are less concerned about violence than Americans are--and that translates into less money for research on the topic. Moreover, some scientists argue that strict regulation of animal studies has dealt a severe blow to a once-proud European tradition of behavioral research on animal aggression.

  4. Numerical analysis of two pile caps with sockets embedded, subject the eccentric compression load

    Directory of Open Access Journals (Sweden)

    R. G. Delalibera

    Full Text Available The structural behavior of pile caps with sockets embedded is influenced by interface of column-socket, which can be smooth or rough. With intent to analyze the behavior of two pile caps with embedded socket, considering the friction between the column and the socket, with eccentric normal load, the numerical simulations were carried out, using a program based on the Finite Element Methods (FEM. In the numerical analysis the non-linear behavior of materials was considered, also the friction between the column and the socket. It was considered perfect bond between the reinforcement and the concrete around. It was observed that the embedded length is preponderant factor in the structural behavior of the analyzed element.

  5. Numerical and experimental behaviour of adhesive joints subjected to peeling load

    Science.gov (United States)

    De Luca, A.; Senatore, F.; Greco, A.

    2016-05-01

    In this paper, a numerical model, based on finite element theory, useful to model the stress-strain state for a bonded single lap joint under peeling load has been presented. The numerical FE model has been developed by means of Abaqus® code in order to reproduce some experimental tests. For FE model validation purpose, the numerical results have been compared with the experimental ones and a good correlation has been achieved. In more detail, the adhesive layer has been modeled by means of cohesive elements. Such elements present some numerical difficulties related to the dependence from the own element size. So, a procedure useful to solve such mesh-dependence has been proposed.

  6. Modelling of stiffness degradation due to cracking in laminates subjected to multi-axial loading.

    Science.gov (United States)

    Kashtalyan, M; Soutis, C

    2016-07-13

    The paper presents an analytical approach to predicting the effect of intra- and interlaminar cracking on residual stiffness properties of the laminate, which can be used in the post-initial failure analysis, taking full account of damage mode interaction. The approach is based on a two-dimensional shear lag stress analysis and the equivalent constraint model of the laminate with multiple damaged plies. The application of the approach to predicting degraded stiffness properties of multidirectional laminates under multi-axial loading is demonstrated on cross-ply glass/epoxy and carbon/epoxy laminates with transverse and longitudinal matrix cracks and crack-induced transverse and longitudinal delaminations. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. © 2016 The Author(s).

  7. Scheduling Jobs with Maintenance Subject to Load-Dependent Duration on a Single Machine

    Directory of Open Access Journals (Sweden)

    Yawei Qi

    2015-01-01

    Full Text Available This paper investigates a scheduling problem on a single machine with maintenance, in which the starting time of the maintenance is given in advance but its duration depends on the load of the machine before the maintenance. The goal is to minimize the makespan. We formulate it as an integer programming model and show that it is NP-hard in the ordinary sense. Then, we propose an FPTAS and point out that a special case is polynomial solvable. Finally, we design fast heuristic algorithms to solve the scheduling problem. Numerical experiments are implemented to evaluate the performance of the proposed heuristic algorithms. The results show the proposed heuristic algorithms are effective.

  8. Biomechanical behavior of human intervertebral discs subjected to long lasting axial loading.

    Science.gov (United States)

    Koeller, W; Funke, F; Hartmann, F

    1984-01-01

    48 lumbar discs were tested; the creep tests lasted between 2 and 6 hours. All discs showed the known creep behavior, i.e. a decrease of height, rate of creep and axial deformability with time. In the first minutes of a test the viscoelastic behavior quickly alters so that the disc behaves more like an elastic body. Loss of mass normally observed after creep tests is due to loss of water. Creep behavior is reproducible if a disc has sufficiently recovered, i.e. if it has regained its initial height. Creep tests on "desiccated" discs revealed that creeping is possible without loss of water and recovery is possible without absorption of water. The type of loading (static or dynamic) has hardly any influence on the biomechanical behavior. Our results indicate, that creep and recovery are chiefly due to extension and contraction of the anular fibers and not to fluid flow.

  9. Interfacial Crack Arrest in Sandwich Panels with Embedded Crack Stoppers Subjected to Fatigue Loading

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J. H.; Berggreen, Christian

    2017-01-01

    of the embedded crack arresters was evaluated in terms of the achieved enhancement of the damage tolerance of the tested sandwich panels. A finite element (FE) model of the experimental setup was used for predicting propagation rates and direction of the crack growth. The FE simulation was based on the adoption......A novel crack arresting device has been implemented in sandwich panels and tested using a special rig to apply out-of-plane loading on the sandwich panel face-sheets. Fatigue crack propagation was induced in the face-core interface of the sandwich panels which met the crack arrester. The effect...... of linear fracture mechanics and a fatigue propagation law (i.e. Paris law) to predict the residual fatigue life-time and behaviour of the test specimens. Finally, a comparison between the experimental results and the numerical simulations was made to validate the numerical predictions as well...

  10. Modelling of stiffness degradation due to cracking in laminates subjected to multi-axial loading

    Science.gov (United States)

    2016-01-01

    The paper presents an analytical approach to predicting the effect of intra- and interlaminar cracking on residual stiffness properties of the laminate, which can be used in the post-initial failure analysis, taking full account of damage mode interaction. The approach is based on a two-dimensional shear lag stress analysis and the equivalent constraint model of the laminate with multiple damaged plies. The application of the approach to predicting degraded stiffness properties of multidirectional laminates under multi-axial loading is demonstrated on cross-ply glass/epoxy and carbon/epoxy laminates with transverse and longitudinal matrix cracks and crack-induced transverse and longitudinal delaminations. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’. PMID:27242290

  11. Extended end-plate connection subjected to monotonic loading: Experimental analysis and FEM simulation

    Science.gov (United States)

    Mureşan, Ioana Cristina; Bâlc, Roxana

    2017-07-01

    This paper presents an experimental investigation of a statically monotonic loaded extended end-plate connection, with preloaded high strength bolts, that was carried out at Laboratory of Faculty of Civil Engineering from Cluj-Napoca. A finite element model using the software package Abaqus [1] was developed in parallel. In order to calibrate the numerical model, the results were analyzed on the basis of moment-rotation curves, stress distribution state and the failure mode of connection. Then, a study was conducted on the numerical model by using a high strength steel (HSS) and changing the stiffness and strength characteristics of some elements. Validation of the numerical modeling was performed against the experimental results and it can be seen that good agreements exist in general.

  12. Modelling the behaviour of composite sandwich structures when subject to air-blast loading

    Directory of Open Access Journals (Sweden)

    H Arora

    2016-09-01

    Full Text Available Large-scale glass fibre reinforced polymer (GFRP and carbon fibre reinforced polymer (CFRP sandwich structures (1.6 m x 1.3 m were subject to explosive air blast (100 kg TNT equivalent at stand-off distances of 14 m. Digital image correlation (DIC was used to obtain full-field data for the rear-face of each deforming target. A steel plate of comparable mass per unit area was also subjected to the same blast conditions for comparison. The experimental data was then verified with finite element models generated in Abaqus/Explicit. Close agreement was obtained between the numerical and experimental results, confirming that the CFRP panels had a superior blast performance to the GFRP panels. Moreover all composite targets sustained localised failures (that were more severe in the GFRP targets but retained their original shape post blast. The rear-skins remained intact for each composite target with core shear failure present.

  13. Behavior of Reinforced Concrete Membrane Elements Subjected to Bidirectional Shear Loads

    OpenAIRE

    Labib, M.; Moslehy, Y.; Ayoub, A

    2013-01-01

    The shear design and behavior of a typical membrane reinforced concrete (RC) element has been extensively studied in the past several decades. Such design requires knowledge of the constitutive behavior of RC elements subjected to a shear stress acting along its plane (in-plane shear). These constitutive models were accurately derived from experimental test data on representative RC panel elements. The true behavior of many large, complex structures, however, involves interaction between the ...

  14. Empirical Model Development for Predicting Shock Response on Composite Materials Subjected to Pyroshock Loading. Volume 2, Part 1; Appendices

    Science.gov (United States)

    Gentz, Steven J.; Ordway, David O.; Parsons, David S.; Garrison, Craig M.; Rodgers, C. Steven; Collins, Brian W.

    2015-01-01

    The NASA Engineering and Safety Center (NESC) received a request to develop an analysis model based on both frequency response and wave propagation analyses for predicting shock response spectrum (SRS) on composite materials subjected to pyroshock loading. The model would account for near-field environment (approximately 9 inches from the source) dominated by direct wave propagation, mid-field environment (approximately 2 feet from the source) characterized by wave propagation and structural resonances, and far-field environment dominated by lower frequency bending waves in the structure. This document contains appendices to the Volume I report.

  15. Protecting the Teaching and Learning Environment: A Hybrid Model for Human Subject Research Public Policy Implementation

    Science.gov (United States)

    Hottenstein, Kristi N.

    2017-01-01

    Regulations for research involving human subjects have long been a critical issue in higher education. Federal public policy for research involving human subjects impacts institutions of higher education by requiring all federally funded research to be passed by an Institutional Review Board (IRB). Undergraduate research is no exception. Given the…

  16. A finite element large deflection random response analysis of beams and plates subjected to acoustic loading

    Science.gov (United States)

    Mei, Chuh; Chiang, C. K.

    1987-01-01

    A finite element formulation is presented for the analysis of beams and rectangular plates undergoing large deflections subjected to Gaussian white noise excitations. Single-mode response is assumed in the present formulation. Root-mean-square (RMS) maximum deflections for simply supported and clamped beams and plates at various sound spectrum levels are obtained and compared with solutions using the Fokker-Planck-Kolmogorov equation and the equivalent linearization methods. RMS maximum stains and equivalent linear frequencies are compared with the equivalent linearization results for assessment of the accuracy of the finite element method.

  17. Robust adaptive control modeling of human arm movements subject to altered gravity and mechanical loads

    Science.gov (United States)

    Tryfonidis, Michail

    It has been observed that during orbital spaceflight the absence of gravitation related sensory inputs causes incongruence between the expected and the actual sensory feedback resulting from voluntary movements. This incongruence results in a reinterpretation or neglect of gravity-induced sensory input signals. Over time, new internal models develop, gradually compensating for the loss of spatial reference. The study of adaptation of goal-directed movements is the main focus of this thesis. The hypothesis is that during the adaptive learning process the neural connections behave in ways that can be described by an adaptive control method. The investigation presented in this thesis includes two different sets of experiments. A series of dart throwing experiments took place onboard the space station Mir. Experiments also took place at the Biomechanics lab at MIT, where the subjects performed a series of continuous trajectory tracking movements while a planar robotic manipulandum exerted external torques on the subjects' moving arms. The experimental hypothesis for both experiments is that during the first few trials the subjects will perform poorly trying to follow a prescribed trajectory, or trying to hit a target. A theoretical framework is developed that is a modification of the sliding control method used in robotics. The new control framework is an attempt to explain the adaptive behavior of the subjects. Numerical simulations of the proposed framework are compared with experimental results and predictions from competitive models. The proposed control methodology extends the results of the sliding mode theory to human motor control. The resulting adaptive control model of the motor system is robust to external dynamics, even those of negative gain, uses only position and velocity feedback, and achieves bounded steady-state error without explicit knowledge of the system's nonlinearities. In addition, the experimental and modeling results demonstrate that

  18. 15 CFR 27.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-01-01

    ... intention of involving human subjects. 27.119 Section 27.119 Commerce and Foreign Trade Office of the Secretary of Commerce PROTECTION OF HUMAN SUBJECTS § 27.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human...

  19. Historic Preservation An unusual way to protect human subjects in research

    Energy Technology Data Exchange (ETDEWEB)

    Prendergast, Ellen L.

    2001-09-15

    The Hanford Cultural Resources Laboratory (HCRL) at the Hanford Site interacts with human subjects in a variety of ways, some of which constitute human subjects research. A key element in this work is determining what constitutes 'research' and thus requires application of special measures to protect human subjects.

  20. Training-Load Distribution in Endurance Runners: Objective Versus Subjective Assessment.

    Science.gov (United States)

    Manzi, Vincenzo; Bovenzi, Antonio; Castagna, Carlo; Sinibaldi Salimei, Paola; Volterrani, Maurizio; Iellamo, Ferdinando

    2015-11-01

    To assess the distribution of exercise intensity in long-distance recreational athletes (LDRs) preparing for a marathon and to test the hypothesis that individual perception of effort could provide training responses similar to those provided by standardized training methodologies. Seven LDRs (age 36.5 ± 3.8 y) were followed during a 5-mo training period culminating with a city marathon. Heart rate at 2.0 and 4.0 mmol/L and maximal heart rate were used to establish 3 intensity training zones. Internal training load (TL) was assessed by training zones and TRIMPi methods. These were compared with the session-rating-of-perceived-exertion (RPE) method. Total time spent in zone 1 was higher than in zones 2 and 3 (76.3% ± 6.4%, 17.3% ± 5.8%, and 6.3% ± 0.9%, respectively; P = .000 for both, ES = 0.98, ES = 0.99). TL quantified by session-RPE provided the same result. The comparison between session-RPE and training-zones-based methods showed no significant difference at the lowest intensity (P = .07, ES = 0.25). A significant correlation was observed between TL RPE and TL TRIMPi at both individual and group levels (r = .79, P training time is spent at low intensity and that this is associated with improved performances. Session-RPE is an easy-to-use training method that provides responses similar to those obtained with standardized training methodologies.

  1. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Science.gov (United States)

    Xie, Weihua; Meng, Songhe; Jin, Hua; Du, Chong; Wang, Libin; Peng, Tao; Scarpa, Fabrizio; Xu, Chenghai

    2016-01-01

    This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs), which are equipped with chemical composition gratings sensors (CCGs). The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE) model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C. PMID:27754356

  2. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Directory of Open Access Journals (Sweden)

    Weihua Xie

    2016-10-01

    Full Text Available This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs, which are equipped with chemical composition gratings sensors (CCGs. The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C.

  3. Filamentary MgB2 wires manufactured by different processes subjected to tensile loading and unloading

    Science.gov (United States)

    Kováč, P.; Kulich, M.; Kopera, L.; Melišek, T.; Kováč, J.; Hušek, I.

    2017-06-01

    A reversible strain effect on the transport critical current (I c) of filamentary MgB2 wires manufactured by three different processes has been examined at 4.2 K and under an external field of 5 T. MgB2 wires with a Nb barrier and a Monel® outer sheath made by powder-in-tube ex situ, in situ and by diffusion of magnesium into the boron process, have been examined. The wire samples were loaded and partially unloaded at progressively higher strain levels to determine the irreversible strain limit (ε irr), which is defined as the ultimate strain where the critical current (I c) is still reversible. It was found that the strain tolerances of the tested MgB2 wires are affected by the production process. The highest annealing temperature (>900 °C), applied in the ex situ process, causes an apparent softening of the Monel® and, together with the poor grain connectivity of MgB2 filaments, leads to the lowest strain tolerance (ε irr = 0.20%). The best grain connectivity, in internal Mg diffusion (IMD)-made MgB2, combined with a stronger Monel® sheath (heat treated at a lower temperature ∼640 °C) results in the best strain tolerance (ε irr = 0.55%).

  4. Viscoelastic damped response of cross-ply laminated shallow spherical shells subjected to various impulsive loads

    Science.gov (United States)

    Şahan, Mehmet Fatih

    2017-11-01

    In this paper, the viscoelastic damped response of cross-ply laminated shallow spherical shells is investigated numerically in a transformed Laplace space. In the proposed approach, the governing differential equations of cross-ply laminated shallow spherical shell are derived using the dynamic version of the principle of virtual displacements. Following this, the Laplace transform is employed in the transient analysis of viscoelastic laminated shell problem. Also, damping can be incorporated with ease in the transformed domain. The transformed time-independent equations in spatial coordinate are solved numerically by Gauss elimination. Numerical inverse transformation of the results into the real domain are operated by the modified Durbin transform method. Verification of the presented method is carried out by comparing the results with those obtained by the Newmark method and ANSYS finite element software. Furthermore, the developed solution approach is applied to problems with several impulsive loads. The novelty of the present study lies in the fact that a combination of the Navier method and Laplace transform is employed in the analysis of cross-ply laminated shallow spherical viscoelastic shells. The numerical sample results have proved that the presented method constitutes a highly accurate and efficient solution, which can be easily applied to the laminated viscoelastic shell problems.

  5. Effect of plastic soil on a retaining wall subjected to surcharge loading

    Directory of Open Access Journals (Sweden)

    Al-Juari Khawla

    2016-01-01

    Full Text Available The seasonal variation and climatic changes play a significant role that affects the stresses exerted on a retaining wall, and the state of stresses in the soil mass behind the wall especially for highly expansive soil. These stresses resulted in the wall moving either away or towards the soil. In this study, a laboratory physical model of the retaining wall formed of a box having (950×900×600 mm dimensions with one side representing the wall being developed. After the soil being laid out in the box in specified layers, specified conditions of saturation and normal stresses were applied. The wall is allowed to move horizontally in several distances (0.1, 0.2, 0.3, 0.6, 0.8, 1.0 , 2.0, 3.0 and 4.0 mm, and the stresses being measured, then the vertical loading was released. The main measured variables during the tests are; the active and passive earth pressures, vertical movement of the soil, total suction and time. Results showed that the lateral earth pressure along the depth of the wall largely decreased when wall moved away from the soil. Total suction was slightly affected during wall’s movement. At unloading stage, the lateral earth pressure decreased at the upper half of wall height, but increased at the other wall part. Total suction was increased at all depths during this stage.

  6. An investigation of interfacial stresses in adhesively-bonded single lap joints subject to transverse pulse loading

    Science.gov (United States)

    Nwankwo, E.; Soleiman Fallah, A.; Louca, L. A.

    2013-04-01

    Debonding in adhesively-bonded lap joints is a detrimental failure mode contingent upon the level of stresses develped in the adhesive. In this work, an analytical model is developed to estimate the peel and shear stresses in an isotropic elastic adhesive in a single lap joint subjected to transverse pulse loads. The proposed analytical model is an extension of the mathematical models developed by He and Rao (Journal of Sound and Vibration 152 (3), (1992) 405-416, 417-425) to study the coupled transverse and longitudinal vibrations of a bonded lap joint system. The adhesive, in this work, is modelled as an elastic isotropic material implemented in Abaqus 6.9-1. The interfacial stresses obtained by finite element simulations were used to validate the proposed analytical model. The maximum peel and shear stresses in the adhesive as predicted by the analytical model were found to correlate well with the maximum stresses predicted by the corresponding numerical models. The peel stresses in the adhesive were found to be higher than shear stresses, a result which is consistent with intuition for transversally loaded joints. The analytical model is able to predict the maxium stresses in the edges where debonding initiates due to the highly asymetrical stress distribution as observed in the finite element simulations and experiment. This phenomenon is consistent with observations made by Vaidya et al. (International Journal of Adhesion & Adhesives 26 (2006) 184-198). The stress distribution under uniformily distributed transverse pulse loading was observed to be similarly asymetric.

  7. Masonry Vaults Subjected To Horizontal Loads: Experimental and Numerical Investigations to Evaluate the Effectiveness of A GFRM Reinforcement

    Science.gov (United States)

    Gattesco, Natalino; Boem, Ingrid

    2017-10-01

    The paper investigates the effectiveness of a modern reinforcement technique based on a Glass Fiber-Reinforced Mortar (GFRM) for the enhancement of the performances of existing masonry vaults subjected to horizontal seismic actions. In fact, the authors recently evidenced, through numerical simulations, that the typical simplified loading patterns generally adopted in the literature for the experimental tests, based on concentrated vertical loads at 1/4 of the span, are not reliable for such a purpose, due to an unrealistic stress distribution. Thus, experimental quasi-static cyclic tests on full-scale masonry vaults based on a specific setup, designed to apply a horizontal load pattern proportional to the mass, were performed. Three samples were tested: an unreinforced vault, a vault reinforced at the extrados and a vault reinforced at the intrados. The experimental results demonstrated the technique effectiveness in both strength and ductility. Moreover, numerical simulations were performed by adopting a simplified FE, smear-crack model, evidencing the good reliability of the prediction by comparison with the experimental results.

  8. [A flexion loading system for knee biomechanics research].

    Science.gov (United States)

    Song, Aijing; Liao, Qingfeng; Li, Xiaofang; Deng, Linhong

    2012-08-01

    It is important to design and build a kinetic loading system for flexing movement of knee joint to study knee biomechanics. The system reported here includes driving device, control device, and flexion angle determination imaging system. The driving device was constructed with a stepper motor and a mechanical transmission with a serried of clamps, shanks and so on, and the driving device was controlled by the control device with micro-control unit, a computer and the serial 232. While the knee joint was driven to move by the stepper motor, the flexion angle of the knee was determined using imaging-based techniques. The system achieved accurate loading and control of speed, extent and duration of knee flexion, as well as fast and non-contract determination of flexion angle during knee flexing movement. The system is simple to build, easy to operate, highly accurate and reliable and it provides an important tool for the study of knee biomechanics, and potentially provides a tool for helping patients of knee surgery during their post operation recovery training.

  9. Effects of walking with a shopping trolley on spinal posture and loading in subjects with neurogenic claudication.

    Science.gov (United States)

    Comer, Christine M; White, Derrick; Conaghan, Philip G; Bird, Howard A; Redmond, Anthony C

    2010-10-01

    To explore possible mechanisms underpinning symptom relief and improved walking tolerance in patients with neurogenic claudication (NC) when pushing a shopping trolley by evaluating the effects of a shopping trolley on spinal posture and loading patterns. An exploratory study of kinematic and kinetic changes in walking with and without pushing a shopping trolley in persons with NC symptoms and a comparison with asymptomatic control subjects. A primary care-based musculoskeletal service. Participants (n=8) with NC symptoms who have anecdotally reported symptomatic improvement when walking with a shopping trolley and a control group of asymptomatic persons (n=8). Shopping trolley. Changes in lumbar spinal sagittal posture and ground reaction force. Subjects with NC and asymptomatic controls walked with significantly more flexed spinal posture (increase in flexion, 3.40°; z=3.516; Pshopping trolley. However, at the midstance point of the gait cycle, controls showed minimal reliance on the trolley, whereas, people with NC showed continued offloading. Both posture and loading are affected by pushing a shopping trolley; however, patients with NC were found to offload the spine throughout the stance phase of gait, whereas asymptomatic controls did not. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  10. CHARACTERIZATION OF 6061 T651 ALUMINUM PLATES SUBJECTED TO HIGH-VELOCITY IMPACT LOADS

    Directory of Open Access Journals (Sweden)

    Evren ÖZŞAHİN

    2011-06-01

    Full Text Available Ballistic response of single or multi-layered metal armor systems subjected to kinetic energy pro-jectiles was investigated in many experimental, theoretical and numerical studies.In this study, 6061 T651 aluminum plates impacted by 9 mm bullets were investigated. Microstructural investigations have been carried out using optical microscopy. Microhardness values were used to determine the strength behavior of the plates. Influence of the plate thickness and impact velocity on the microstructure has been evaluated. It was concluded from the study that thinner plates are more prone to deformation hardening with high penetration depth values even at low impact velocities while thick plates are more susceptible to thermal softening with less penetration depths. Maximum hardness values were obtained just below the impact zone in both plate thicknesses.

  11. Finite Element Simulation and Assessment of Single-Degree-of-Freedom Prediction Methodology for Insulated Concrete Sandwich Panels Subjected to Blast Loads

    Science.gov (United States)

    2011-02-01

    sandwich panels for blast loads. blast load; finite element modeling; large deflection behavior; load-deflection response; precast concrete ; prestressed ...of Precast/ Prestressed Concrete Structures for Blast ...............................................6 3. MODEL DEVELOPMENT AND VALIDATION...Laboratory (AFRL) and a Daniel P. Jenny Research Fellowship Grant from the Precast/ Prestressed Concrete Institute (PCI). The current technical points of

  12. Spinal loads and trunk muscles forces during level walking - A combined in vivo and in silico study on six subjects.

    Science.gov (United States)

    Arshad, Rizwan; Angelini, Lorenza; Zander, Thomas; Di Puccio, Francesca; El-Rich, Marwan; Schmidt, Hendrik

    2017-08-26

    During level walking, lumbar spine is subjected to cyclic movements and intricate loading of the spinal discs and trunk musculature. This study aimed to estimate the spinal loads (T12-S1) and trunk muscles forces during a complete gait cycle. Six men, 24-33years walk barefoot at self-selected speed (4-5km/h). 3D kinematics and ground reaction forces were recorded using a motion capturing system and two force plates, implemented in an inverse dynamic musculoskeletal model to predict the spinal loads and trunk muscles forces. Additionally, the sensitivity of the intra-abdominal pressure and lumbar segment rotational stiffness was investigated. Peak spinal loads and trunk muscle forces were between the gait instances of heel strike and toe off. In L4-L5 segment, sensitivity analysis showed that average peak compressive, antero-posterior and medio-lateral shear forces were 130-179%, 2-15% and 1-6%, with max standard deviation (±STD) of 40%, 6% and 3% of the body weight. Average peak global muscles forces were 24-55% (longissimus thoracis), 11-23% (iliocostalis thoracis), 12-16% (external oblique), 17-25% (internal oblique) and 0-8% (rectus abdominus) of body weight whereas, the average peak local muscles forces were 11-19% (longissimus lumborum), 14-31% (iliocostalis lumborum) and 12-17% (multifidus). Maximum±STD of the global and local muscles forces were 13% and 8% of the body weight. Large inter-individual differences were found in peak compressive and trunk muscles forces whereas the sensitivity analysis also showed a substantial variation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Potassium changes in trained subjects after potassium loading and during restriction of muscular activity and chronic hyperhydration.

    Science.gov (United States)

    Zorbas, Y G; Federenko, Y F; Naexu, K A

    1996-01-01

    The objective of this investigation was to determine whether urinary and plasma potassium changes developed during prolonged hypokinesia (HK) (decreased number of km/d) in endurance-trained subjects could be minimized or reversed with a daily intake of fluid and salt supplementation (FSS). The studies were performed on 30 endurance-trained male volunteers aged 23-26 yr with an average peak oxygen uptake of 65 mL/kg min during 364 d of HK. All volunteers were on an average of 13.8 km/d prior to their exposure to HK. All volunteers were randomly divided into three groups: 10 volunteers were placed continuously under an average of 14.0 km/d (control subjects), 10 volunteers were subjected continuously to an average of 2.7 km/d (unsupplemented hypokinetic subjects), and 10 volunteers were submitted continuously to an average of 2.7 km/d, and consumed daily an additional amount of 0.1 g sodium chloride (NaCl)/kg body wt and 30 mL water/kg body wt (supplemented hypokinetic subjects). During the prehypokinetic period of 60 d and during the hypokinetic period of 364 d, potassium loading tests were performed with 1.5-1.7 mEq potassium chloride/kg body wt, and potassium, sodium, and chloride excretion in urine and potassium, sodium, and chloride in plasma were determined. In the unsupplemented hypokinetic volunteers, urinary excretion of electrolytes and concentrations of electrolytes in plasma increased significantly as compared to the control and supplemented hypokinetic groups of volunteers. It was concluded that daily intake of fluid and salt supplementation had a favorable effect on regulation of urinary and plasma potassium changes in trained subjects during prolonged HK.

  14. Cognitive load theory, educational research, and instructional design; some food for thought

    NARCIS (Netherlands)

    de Jong, Anthonius J.M.

    2010-01-01

    Cognitive load is a theoretical notion with an increasingly central role in the educational research literature. The basic idea of cognitive load theory is that cognitive capacity in working memory is limited, so that if a learning task requires too much capacity, learning will be hampered. The

  15. The Journal Project and the I in Qualitative Research: Three Theoretical Lenses on Subjectivity and Self

    Science.gov (United States)

    Davidson, Judith

    2012-01-01

    From the beginnings of qualitative research in the late 19th century to today, researchers have struggled to make sense of the notion of self or subjectivity; in other words, the I in the research. We ask ourselves: Who is the researcher? How is their notion of self present during research? How is research a site for contested notions of self? Who…

  16. Graphite/Polyimide Composites Subjected to Biaxial Loads at Elevated Temperatures

    Science.gov (United States)

    Kumosa, Maciej S.; Sutter, J. K.

    2007-01-01

    First, we will review our most important research accomplishments from a five year study concerned with the prediction of mechanical properties of unidirectional and woven graphite/polyimide composites based on T650-35, M40J and M60J fibers embedded in either PMR-15 or PMR-II-50 polyimide resins. Then, an aging model recently developed for the composites aged in nitrogen will be proposed and experimentally verified on an eight harness satin (8HS) woven T650-35/PMR-15 composite aged in nitrogen at 315 C for up to 1500 hours. The study was supported jointly between 1999 and 2005 by the AFOSR, the NASA Glenn Research Center, and the National Science Foundation.

  17. [Disability studies: social exclusion a research subject].

    Science.gov (United States)

    Zander, Michael

    2016-09-01

    The article presents disability studies and elaborates, as their central feature, the distinction between societal disability and impairment which can be described on an individual and medical level. Disability studies define disability as socially caused exclusion. Participation and inclusion, seen as sociopolitical control and counter-terms, do, in fact, have a different content, depending on usage and context. Using the example of the International Classification of Functioning (ICF) and the United Nations Convention on the Rights of Persons with Disabilities (UN CRPD), the respective understanding of disability is depicted. Against this background, the deficits of implementation of the UN CRPD, as criticized by the responsible UN Committee, are shown. Finally, a research agenda for disability studies is outlined, that deals with, among other things, implementation strategies and conflicts of interest in terms of inclusion, furthering widely unquestioned economic conditions and especially the negative impact of European austerity politics.

  18. [Literature review of the subject of a research project].

    Science.gov (United States)

    Vilanova, J C

    2012-01-01

    It can be very complicated to obtain relevant information through searching the medical literature if you do not know how it is organized and indexed or if you do not know how to use the specialized databases. For a successful review of the literature, you need to know what you are looking for and the key words for an effective search of the specialized databases and libraries and especially of the internet. It is essential to critically evaluate the information selected. Finally, using a reference manager can facilitate the gathering, organization, systematization, and integration of the bibliographic references in the documents generated in the study. This article aims to provide guidelines for efficient searching for information and for accurate, critical use of the literature. It makes recommendations about strategies for managing references to help to ensure the success of a research project. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  19. Mobility power flow analysis of an L-shaped plate structure subjected to distributed loading

    Science.gov (United States)

    Cuschieri, J. M.; Cimmerman, B.

    1990-01-01

    An analytical investigation based in the Mobility Power Flow (MPF) method is presented for the determination of the vibrational response and power flow for two coupled flat plate structures in an L-shaped configuration, subjected to distributed excitation. The principle of the MPF method consists of dividing the global structure into a series of subsystems coupled together using mobility functions. Each separate subsystem is analyzed independently to determine the structural mobility functions for the junction and excitation locations. The mobility functions, together with the characteristics of the junction between the subsystems, are then used to determine the response of the global structure and the MPF. In the considered coupled plate structure, MPF expressions are derived for distributed mechanical excitation which is independent of the structure response. However using a similar approach with some modifications excitation by an acoustic plane wave can be considered. Some modifications are required to deal with the latter case are necessary because the forces (acoustic pressure) acting on the structure are dependent on the response of the structure due to the presence of the scattered pressure.

  20. 48 CFR 752.7012 - Protection of the individual as a research subject.

    Science.gov (United States)

    2010-10-01

    ... in Research Supported by USAID”, issued April 19, 1995, as from time to time amended (a copy of which... Policy when humans are the subject of research, as defined in 22 CFR 225.102(d), performed as part of the... individual as a research subject. 752.7012 Section 752.7012 Federal Acquisition Regulations System AGENCY FOR...

  1. 14 CFR 1230.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Research undertaken without the intention... SPACE ADMINISTRATION PROTECTION OF HUMAN SUBJECTS § 1230.119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving...

  2. 10 CFR 745.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Research undertaken without the intention of involving....119 Research undertaken without the intention of involving human subjects. In the event research is undertaken without the intention of involving human subjects, but it is later proposed to involve human...

  3. Single-Subject Designs and Action Research in the K-12 Setting

    Science.gov (United States)

    Forbes, Sean A.; Ross, Margaret E.; Chesser, Svetlana S.

    2011-01-01

    In as much as educational research is concerned with individual student assessment and development, it is surprising that single-subject designs are not more readily utilized in classroom-based action research. The purpose of this article is to emphasize benefits of single-subject research in the K-12 setting, given that teachers teach and assess…

  4. Initial results of a study into the estimation of the development of frequency lock-in for offshore structures subjected to ice loading

    NARCIS (Netherlands)

    Hendrikse, H.; Seidel, Marc; Metrikine, A.; Loset, Sveinung

    2017-01-01

    Ice-induced vibrations have to be considered in design of vertically sided offshore structures subjected to loading by sea ice, such as offshore wind turbines and oil- and gas platforms. The interaction between ice and structure may result in high global peak loads and the occurring structural

  5. Subject of research on effects of tourism on population development

    Directory of Open Access Journals (Sweden)

    Devedžić Mirjana

    2007-01-01

    Full Text Available The importance of tourism in the context of economic and demographic recovery of certain regions has created an image of tourism as a development catalyst. Thus strategies of revitalization in depopulated and passive regions often consider tourism as an activity that can speed up the development and successfully valorize existing natural, cultural and demographic potentials. This "key" is used mainly in the absence of other development resources since tourism valorizes issues that other industries ignore (landscape features, ethnical heritage, authentic folk architecture, etc. In addition it is more difficult to recommend the right forms of tourism to be developed in depopulated regions, as well as to estimate the resulting economic and demographic effects. To this end, there are success stories, but there is also evidence of non-rational initiatives and projects that were never completed. This paper attempts to discover the most logical links between population development and tourism development, based on some important characteristics of population development. The characteristics used are overall population increase, population migrations, population structures and changes in households. They were selected because they best reflect not only direct, but also indirect multiplicative effects of tourism. Along with the theoretical and methodological background, the research is also supported by selected examples, interviews, and demographic analyzes. The effects are not universal. They depend on the region, the kind of tourism and the degree of its development, the demographic situation as it is, and the research approach, since global and local effects need not necessarily be unidirectional. Population increase initiated by tourism development is achieved due to the migration component, but the effects are most obvious at the level of tourist regions and their tourist centers. One can also note counter processes in some places that have tourist

  6. Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

    Science.gov (United States)

    Benyo, Theresa L.; Steinetz, Bruce M.; Hendricks, Robert C.; Martin, Richard E.; Forsley, Lawrence P.; Daniels, Christopher C.; Chait, Arnon; Pines, Vladimir; Pines, Marianna; Penney, Nicholas; hide

    2017-01-01

    Results are presented from an exploratory study involving x-ray irradiation of select deuterated materials. Titanium deuteride plus deuterated polyethylene, deuterated polyethylene alone, and for control, hydrogen-based polyethylene samples and nondeuterated titanium samples were exposed to x-ray irradiation. These samples were exposed to various energy levels from 65 to 280 kV with prescribed electron flux from 500 to 9000 µA impinging on a tungsten braking target, with total exposure times ranging from 55 to 280 min. Gamma activity was measured using a high-purity germanium (HPGe) detector, and for all samples no gamma activity above background was detected. Alpha and beta activities were measured using a gas proportional counter, and for select samples beta activity was measured with a liquid scintillator spectrometer. The majority of the deuterated materials subjected to the microfocus x-ray irradiation exhibited postexposure beta activity above background and several showed short-lived alpha activity. The HPE and nondeuterated titanium control samples exposed to the x-ray irradiation showed no postexposure alpha or beta activities above background. Several of the samples (SL10A, SL16, SL17A) showed beta activity above background with a greater than 4s confidence level, months after exposure. Portions of SL10A, SL16, and SL17A samples were also scanned using a beta scintillator and found to have beta activity in the tritium energy band, continuing without noticeable decay for over 12 months. Beta scintillation investigation of as-received materials (before x-ray exposure) showed no beta activity in the tritium energy band, indicating the beta emitters were not in the starting materials.

  7. Evaluation of a load cell model for dynamic calibration of the rotor systems research aircraft

    Science.gov (United States)

    Duval, R. W.; Bahrami, H.; Wellman, B.

    1985-01-01

    The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission system from the fuselage. An analytical model of the relationship between applied rotor loads and the resulting load cell measurements is derived by applying a force-and-moment balance to the isolated rotor/transmission system. The model is then used to estimate the applied loads from measured load cell data, as obtained from a ground-based shake test. Using nominal design values for the parameters, the estimation errors, for the case of lateral forcing, were shown to be on the order of the sensor measurement noise in all but the roll axis. An unmodeled external load appears to be the source of the error in this axis.

  8. Research on automatic loading & unloading technology for vertical hot ring rolling process

    Directory of Open Access Journals (Sweden)

    Xiaokai Wang

    2015-01-01

    Full Text Available The automatic loading & unloading technology is the key to the automatic ring production line. In this paper, the automatic vertical hot ring rolling (VHRR process is taken as the target, the method of the loading & unloading for VHRR is proposed, and the mechanical structure of loading & unloading system is designed, The virtual prototype model of VHRR mill and loading & unloading mechanism is established, and the coordinated control method of VHRR mill and loading & unloading auxiliaries is studied, the movement trace and dynamic characteristic of the critical components are obtained. Finally, a series of hot ring rolling tests are conducted on the VHRR mill, and the production rhythm and the formed rings' geometric precision are analysed. The tests results show that the loading & unloading technology can meet the high quality and high efficiency ring production requirement. The research conclusions have practical significance for the large-scale automatic ring production.

  9. REVIEW OF PRACTICE FOR DEEPLY EMBEDDED/BURIED NPP STRUCTURES SUBJECT TO SEISMIC LOADINGS.

    Energy Technology Data Exchange (ETDEWEB)

    XU,J.HOFMAYER,C.MILLER,C.GRAVES,H.

    2004-03-24

    Motivated by many design considerations, several conceptual designs for advanced reactors have proposed that the entire reactor building and a significant portion of the steam generator building will be either partially or completely embedded below grade. For the analysis of seismic events, the soil-structure interaction (SSI) effect and passive earth pressure for these types of deeply embedded structures will have a significant influence on the predicted seismic response. Sponsored by the US Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) is carrying out a research program to assess the significance of these proposed design features for advanced reactors, and to evaluate the existing analytical methods to determine their applicability and adequacy in capturing the seismic behavior of the proposed designs. This paper summarizes a literature review performed by BNL to determine the state of knowledge and practice for seismic analyses of deeply embedded and/or buried (DEB) nuclear containment type structures. Included in the paper is BNL's review of the open literature of existing standards, tests, and practices that have been used in the design and analysis of DEB structures. The paper also provides BNL's evaluation of available codes and guidelines with respect to seismic design practice of DEB structures. Based on BNL's review, a discussion is provided to highlight the applicability of the existing technologies for seismic analyses of DEB structures and to identify gaps that may exist in knowledge and potential issues that may require better understanding and further research.

  10. Estimation of dynamic rotor loads for the rotor systems research aircraft: Methodology development and validation

    Science.gov (United States)

    Duval, R. W.; Bahrami, M.

    1985-01-01

    The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission systm from the fuselage. A mathematical model relating applied rotor loads and inertial loads of the rotor/transmission system to the load cell response is required to allow the load cells to be used to estimate rotor loads from flight data. Such a model is derived analytically by applying a force and moment balance to the isolated rotor/transmission system. The model is tested by comparing its estimated values of applied rotor loads with measured values obtained from a ground based shake test. Discrepancies in the comparison are used to isolate sources of unmodeled external loads. Once the structure of the mathematical model has been validated by comparison with experimental data, the parameters must be identified. Since the parameters may vary with flight condition it is desirable to identify the parameters directly from the flight data. A Maximum Likelihood identification algorithm is derived for this purpose and tested using a computer simulation of load cell data. The identification is found to converge within 10 samples. The rapid convergence facilitates tracking of time varying parameters of the load cell model in flight.

  11. Nonlinear Response of Thin Cylindrical Shells with Longitudinal Cracks and Subjected to Internal Pressure and Axial compression Loads

    Science.gov (United States)

    Starnes, James H.; Rose, Cheryl A.

    1998-01-01

    The results of an analytical study of the nonlinear response of a thin unstiffened aluminum cylindrical shell with a longitudinal crack are presented. The shell is analyzed with a nonlinear shell analysis code that maintains the shell in a nonlinear equilibrium state while the crack is grown. The analysis accurately accounts for global and local structural response phenomena. Results are presented for internal pressure, axial compression, and combined internal pressure and axial compression loads. The effects of varying crack length on the nonlinear response of the shell subjected to internal pressure are described. The effects of varying crack length on the prebuckling, buckling and postbuckling responses of the shell subjected to axial compression, and subjected to combined internal pressure and axial compression are also described. The results indicate that the nonlinear interaction between the in-plane stress resultants and the out-of-plane displacements near a crack can significantly affect the structural response of the shell. The results also indicate that crack growth instabilities and shell buckling instabilities can both affect the response of the shell as the crack length is increased.

  12. Structural Behaviour of Precast Reinforced Concrete Frames on a Non-Engineered Building Subjected to Lateral Loads

    Directory of Open Access Journals (Sweden)

    Mochamad Teguh

    2016-06-01

    Full Text Available Past earthquakes in Indonesia have caused loss of life and major damage to buildings and infrastructure. Most of the damage was experienced on non-engineered buildings, which were conventionally built with less consideration of earthquake resistant design. In this research, a precast system was introduced for non-engineered building structures to connect their practical beams and columns as a reinforced concrete frame. This paper presents experimental tests on precast reinforced concrete frames with and without infill masonry walls using local materials. All undamaged and repaired specimens were set up with the same loading arrangements where lateral loads were gradually applied to one side of the beam column joint until the ultimate load was reached. Simple retrofitting and strengthening techniques were applied to the damaged specimens were conducted. The results were compared based on the experimental tests, and showed that retrofitted and strengthened specimens significantly increased their strength, stiffness, and displacement ductility to improve the structural behaviour of non-engineered building structures.

  13. Influence of Dissimilar Adherends on the Stress Distribution in Adhesively Bonded Composite Joints Subjected to Impact Loadings

    Science.gov (United States)

    Hazimeh, R.; Challita, G.; Khalil, K.; Othman, R.

    2015-01-01

    The influence of nonsymmetric rotation of laminates on the shear and peel stresses in the adhesive layer of adhesively bonded double-lap composite joints (DLJ) subjected to in-plane impact compressive loadings is investigated by using a three-dimensional finite-element analysis. The compressive in-plane impact on DLJ is simulated using the direct Hopkinson bar system, and the specimen is impacted by an incident bar. It is found that the rotation of any adherend from the 0° orientation leads to a decrease in the average shear stress in the adhesive layer, but the maximum peel stress is affected only by the longitudinal stiffness of the outer adherend and decreases when this stiffness diminishes.

  14. Optimization Design of Structures Subjected to Transient Loads Using First and Second Derivatives of Dynamic Displacement and Stress

    Directory of Open Access Journals (Sweden)

    Qimao Liu

    2012-01-01

    Full Text Available This paper developed an effective optimization method, i.e., gradient-Hessian matrix-based method or second order method, of frame structures subjected to the transient loads. An algorithm of first and second derivatives of dynamic displacement and stress with respect to design variables is formulated based on the Newmark method. The inequality time-dependent constraint problem is converted into a sequence of appropriately formed time-independent unconstrained problems using the integral interior point penalty function method. The gradient and Hessian matrixes of the integral interior point penalty functions are also computed. Then the Marquardt's method is employed to solve unconstrained problems. The numerical results show that the optimal design method proposed in this paper can obtain the local optimum design of frame structures and sometimes is more efficient than the augmented Lagrange multiplier method.

  15. Bioaugmentation of an acetate-oxidising anaerobic consortium in up-flow sludge blanket reactor subjected to high ammonia loads

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

    . in association with Methanoculleus spp. strain MAB1), is an acetate oxidising methanogenic consortium that can produce methane (CH4) at high ammonia levels. In the current study the bioaugmentation of the SAO culture in a mesophilic up-flow anaerobic sludge blanket (UASB) reactor subjected to high ammonia loads...... was tested. The co-cultivation in fed-batch of a fast-growing hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) with the SAO culture was also investigated. Results obtained clearly demonstrated that bioaugmentation of SAO culture in a UASB reactor was not possible most probably due to the slow...... growth of the culture. The incubation period (duration of lag+exponential phase) of SAO culture was reduced more than 30% when it was cocultivated with Methanoculleus bourgensis, in fed-batch reactors. Therefore, the bioaugmentation of the SAO culture along with Methanoculleus bourgensis in a UASB...

  16. Interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device – Numerical modelling

    DEFF Research Database (Denmark)

    Martakos, G.; Andreasen, J.H.; Berggreen, Christian

    2017-01-01

    fatigue test study. Based on a linear elastic fracture mechanics approach, the developed FE model is utilised to simulate crack propagation and arrest in foam-cored sandwich beam specimens subjected to fatigue loading conditions. The effect of the crack arresters on the fatigue life is analysed......A novel crack arresting device is implemented in foam-cored composite sandwich beams and tested using the Sandwich Tear Test (STT) configuration. A finite element model of the setup is developed, and the predictions are correlated with observations and results from a recently conducted experimental......, and the predictive results are subsequently compared with the observations from the previously conducted fatigue tests. The FE model predicts the energy release rate and the mode mixity based on the derived crack surface displacements, utilising algorithms for the prediction of accelerated fatigue crack growth...

  17. Effect of nonlinear material behavior of laminated composite plates with central rectangular hole subjected to out -of- plane loading

    Directory of Open Access Journals (Sweden)

    Abu-Farsakh Ghazi

    2017-01-01

    Full Text Available The purpose of this paper is to investigate the effect of nonlinear material behavior on four layered, symmetric; angle-ply laminated composite plate with various fiber-orientation angles; (θ = 30°, 45° and 60°. The plate has a central square-hole and subjected to out-of-plane uniformly distributed load. The effect of Stress Concentration Factor (SCF resulting from redistribution of in-plane stresses (σx, σy, τxy around the hole was taken into consideration. Square plates with simply supported boundary conditions were considered in the present study. The analysis was carried out utilizing the ANSYS-computer program. The presence of a central hole was found to concentrate the maximum stresses at the corners of the hole. The nonlinear material behavior was found to redistribute the in-plane stresses more reasonably and smoothly around the hole-perimeter and hence resulting in smaller SCF-values.

  18. Plasma hormone levels in human subject during stress loads in microgravity and at readaptation to Earth's gravity.

    Science.gov (United States)

    Macho, L; Koska, J; Ksinantova, L; Vigas, M; Noskov, V B; Grigoriev, A I; Kvetnansky, R

    2001-07-01

    In great part of the investigations of endocrine system functions in astronauts during space flights the plasma levels of hormones and metabolites were determined only in resting conditions, usually from one blood sample collection. Such levels reflected the psychical and physical state and new hormonal homeostasis of organism at the time of blood collection, however, the functional capacity of neuroendocrine system to respond to various stress stimuli during space flight remained unknown. The aim of present investigations was to study dynamic changes of hormone levels during the stress and metabolic loads (insulin induced hypoglycemia, physical exercise and oral glucose tolerance test) at the exposure of human subject to microgravity on the space station MIR. The responses of sympatico-adrenomedullary system to these stress and workloads were presented by Kvetnansky et al.

  19. Stress-intensity factor equations for cracks in three-dimensional finite bodies subjected to tension and bending loads

    Science.gov (United States)

    Newman, J. C., Jr.; Raju, I. S.

    1984-01-01

    Stress intensity factor equations are presented for an embedded elliptical crack, a semielliptical surface crack, a quarter elliptical corner crack, a semielliptical surface crack along the bore of a circular hole, and a quarter elliptical corner crack at the edge of a circular hole in finite plates. The plates were subjected to either remote tension or bending loads. The stress intensity factors used to develop these equations were obtained from previous three dimensional finite element analyses of these crack configurations. The equations give stress intensity factors as a function of parametric angle, crack depth, crack length, plate thickness, and, where applicable, hole radius. The ratio of crack depth to plate thickness ranged from 0 to 1, the ratio of crack depth to crack length ranged from 0.2 to 2, and the ratio of hole radius to plate thickness ranged from 0.5 to 2. The effects of plate width on stress intensity variation along the crack front were also included.

  20. The "Subject of Ethics" and Educational Research OR Ethics or Politics? Yes Please!

    Science.gov (United States)

    Bazzul, Jesse

    2017-01-01

    This paper outlines a theoretical context for research into "the subject of ethics" in terms of how students come to see themselves as self-reflective actors. I maintain that the "subject of ethics," or ethical subjectivity, has been overlooked as a necessary aspect of creating politically transformative spaces in education. At…

  1. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading.

    Science.gov (United States)

    Dung, Cao Vu; Sasaki, Eiichi

    2016-04-27

    Polyvinylidene Flouride (PVDF) is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental "stress-averaging" mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the "stress-averaging" mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam's modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor's output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  2. Identification of the Response of a Controlled Building Structure Subjected to Seismic Load by Using Nonlinear System Models

    Directory of Open Access Journals (Sweden)

    Mosbeh R. Kaloop

    2016-10-01

    Full Text Available The present study investigates the prediction efficiency of nonlinear system-identification models, in assessing the behavior of a coupled structure-passive vibration controller. Two system-identification models, including Nonlinear AutoRegresive with eXogenous inputs (NARX and adaptive neuro-fuzzy inference system (ANFIS, are used to model the behavior of an experimentally scaled three-story building incorporated with a tuned mass damper (TMD subjected to seismic loads. The experimental study is performed to generate the input and output data sets for training and testing the designed models. The parameters of root-mean-squared error, mean absolute error and determination coefficient statistics are used to compare the performance of the aforementioned models. A TMD controller system works efficiently to mitigate the structural vibration. The results revealed that the NARX and ANFIS models could be used to identify the response of a controlled structure. The parameters of both two time-delays of the structure response and the seismic load were proven to be effective tools in identifying the performance of the models. A comparison based on the parametric evaluation of the two methods showed that the NARX model outperforms the ANFIS model in identifying structures response.

  3. Buckling of Carbon Nanotube-Reinforced Polymer Laminated Composite Materials Subjected to Axial Compression and Shear Loadings

    Science.gov (United States)

    Riddick, J. C.; Gates, T. S.; Frankland, S.-J. V.

    2005-01-01

    A multi-scale method to predict the stiffness and stability properties of carbon nanotube-reinforced laminates has been developed. This method is used in the prediction of the buckling behavior of laminated carbon nanotube-polyethylene composites formed by stacking layers of carbon nanotube-reinforced polymer with the nanotube alignment axes of each layer oriented in different directions. Linking of intrinsic, nanoscale-material definitions to finite scale-structural properties is achieved via a hierarchical approach in which the elastic properties of the reinforced layers are predicted by an equivalent continuum modeling technique. Solutions for infinitely long symmetrically laminated nanotube-reinforced laminates with simply-supported or clamped edges subjected to axial compression and shear loadings are presented. The study focuses on the influence of nanotube volume fraction, length, orientation, and functionalization on finite-scale laminate response. Results indicate that for the selected laminate configurations considered in this study, angle-ply laminates composed of aligned, non-functionalized carbon nanotube-reinforced lamina exhibit the greatest buckling resistance with 1% nanotube volume fraction of 450 nm uniformly-distributed carbon nanotubes. In addition, hybrid laminates were considered by varying either the volume fraction or nanotube length through-the-thickness of a quasi-isotropic laminate. The ratio of buckling load-to-nanotube weight percent for the hybrid laminates considered indicate the potential for increasing the buckling efficiency of nanotube-reinforced laminates by optimizing nanotube size and proportion with respect to laminate configuration.

  4. The effect of lifting and lowering an external load on repositioning error of trunk flexion-extension in subjects with and without low back pain.

    Science.gov (United States)

    Lin, Yang Hua; Sun, Ming Hui

    2006-07-01

    To determine whether the repositioning error of trunk flexion-extension in individuals with low back pain is different from that in those not experiencing low back pain when lifting and lowering external loads. A case-control study. Physical therapy department of a medical centre. Twenty subjects with subacute low back pain and 20 control subjects without low back pain. Tasks with and without lifting and lowering an external load. The trunk repositioning errors were measured with Measurand Shape Tape. In subjects with low back pain, trunk repositioning errors were significantly reduced when lifting and lowering an external load in the direction of flexion (3.77 +/- 1.26 degrees in a loaded condition versus 4.82 +/- 2.97 degrees in an unloaded condition; P loaded condition versus 5.03 +/- 3.74 degrees in an unloaded condition; P external load in the direction of flexion (2.80 +/- 1.39 degrees in a loaded condition versus 2.63 +/- 1.24 degrees in an unloaded condition; P > 0.05) and extension (2.87 +/- 11.40 degrees in a loaded condition versus 3.15 +/- 11.50 degrees in an unloaded condition; P > 0.05). The direction of motion (trunk flexion or extension) was not shown to be significant in this study. Performing the task whilst lifting or lowering a submaximal load showed a reduced trunk repositioning error in subjects with subacute low back pain. Lifting and lowering a submaximal load might be considered as one of the rehabilitative strategies to hasten a return to work.

  5. Using Single-Subject Research to Establish the Evidence Base of Special Education

    Science.gov (United States)

    Tankersley, Melody; Harjusola-Webb, Sanna; Landrum, Timothy J.

    2008-01-01

    Research in the field of special education often incorporates single-subject designs to investigate the effectiveness of educational practices for students with disabilities. As such, it is important that educators and educational professionals understand the characteristics of single-subject research methodologies and how those characteristics…

  6. 38 CFR 17.85 - Treatment of research-related injuries to human subjects.

    Science.gov (United States)

    2010-07-01

    ...-related injuries to human subjects. 17.85 Section 17.85 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS MEDICAL Research-Related Injuries § 17.85 Treatment of research-related injuries... apply to: (1) Treatment for injuries due to noncompliance by a subject with study procedures, or (2...

  7. 45 CFR 690.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Research undertaken without the intention of involving human subjects. 690.119 Section 690.119 Public Welfare Regulations Relating to Public Welfare... the intention of involving human subjects. In the event research is undertaken without the intention...

  8. 38 CFR 16.119 - Research undertaken without the intention of involving human subjects.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Research undertaken without the intention of involving human subjects. 16.119 Section 16.119 Pensions, Bonuses, and Veterans... the intention of involving human subjects. In the event research is undertaken without the intention...

  9. Impaired Sleep Mediates the Negative Effects of Training Load on Subjective Well-Being in Female Youth Athletes.

    Science.gov (United States)

    Watson, Andrew; Brickson, Stacey

    2018-02-01

    Although increased training load (TL) and impaired sleep are associated with decreases in subjective well-being in adult athletes, these relationships among female youth athletes are unclear. It is unknown whether the effects of sleep and TL on well-being are independent or whether alterations in sleep mediate the effects of TL on subjective well-being. Sleep and TL exert independent effects on subjective well-being among youth athletes, although alterations in sleep mediate a significant portion of the effect of TL on well-being in female youth athletes. Prospective cohort study. Level 4. A total of 65 female soccer athletes (age range, 13-18 years) were monitored for 1 year. Daily TL was determined by session rating of perceived exertion and converted to z-scores. Every morning, participants recorded sleep duration in hours and rated stress, mood, fatigue, and soreness on a scale from -3 to +3 (worst to best). Linear mixed-effects models and mediation analysis were used to evaluate the independent effects of TL and sleep on well-being. Average sleep duration was 7.9 ± 1.4 hours during the study period. In the multivariable model, TL and sleep duration were independently associated with fatigue (TL: β = -0.19, P < 0.001; sleep: β = 0.15, P < 0.001), mood (TL: β = -0.030, P = 0.014; sleep: β = 0.13, P < 0.001), stress (TL: β = -0.055, P = 0.001; sleep: β = 0.13, P < 0.001), and soreness (TL: β = -0.31, P < 0.001; sleep: β = 0.022, P = 0.042). Sleep duration mediated a significant portion of the effect of TL on mood (26.8%, P < 0.001), fatigue (12.6%, P < 0.001), and stress (24.5%, P < 0.001). Among female youth athletes, decreased sleep duration and increased TL are independently associated with impairments of subjective well-being. In addition, decreased sleep mediates a significant portion of the negative effect of increases in TL on subjective well-being. Monitoring and promoting sleep among female adolescent athletes may significantly improve

  10. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Liu Cao

    2017-01-01

    Full Text Available The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF magnetic stimulation on surface electromyography (SEMG signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject’s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS, median frequency (MDF, and sample entropy (SampEn, were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05. In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p<0.001 and MDF and SampEn were significantly smaller (all p<0.001.

  11. Performance Evaluation of Waterproofing Membrane Systems Subject to the Concrete Joint Load Behavior of Below-Grade Concrete Structures

    Directory of Open Access Journals (Sweden)

    Jaeyoung Song

    2017-11-01

    Full Text Available Below-grade structures such as parking lots, underground subway tunnels, and basements are growing in scale and reaching deeper below-ground levels. In this type of environment, they become subject to higher water pressure. The concrete material of the structures is exposed to wet conditions for longer periods of time, which makes the proper adhesion of waterproofing membranes difficult. Joint movements from increased structural settlement, thermal expansion/shrinkage, and physical loads from external sources (e.g., vehicles make securing durable waterproofing challenging. While ASTM Guides, Korean Codes, and BS Practice Codes on below-grade waterproofing stress the importance of manufacturer specification for quality control, ensuring high quality waterproofing for the ever-changing scale of construction remains a challenge. This study proposes a new evaluation method and criteria which allow for the selection of waterproofing membranes based on specific performance attributes and workmanship. It subjects six different waterproofing membrane systems (installed on dry and wet surface conditioned mortar slab specimens with an artificial joint to different cyclic movement widths to 300 cycles in water to demonstrate that inadequate material properties and workmanship are key causes for leakages.

  12. What is the subjective cost of cognitive effort? Load, trait, and aging effects revealed by economic preference.

    Directory of Open Access Journals (Sweden)

    Andrew Westbrook

    Full Text Available It has long been assumed that people treat cognitive effort as costly, but also that such effort costs may vary greatly across individuals. Individual differences in subjective effort could present a major and pervasive confound in behavioral and neuroscience assessments, by conflating cognitive ability with cognitive motivation. Self-report cognitive effort scales have been developed, but objective measures are lacking. In this study, we use the behavioral economic approach of revealed preferences to quantify subjective effort. Specifically, we adapted a well-established discounting paradigm to measure the extent to which cognitive effort causes participants to discount monetary rewards. The resulting metrics are sensitive to both within-individual factors, including objective load and reward amount, and between-individual factors, including age and trait cognitive engagement. We further validate cognitive effort discounting by benchmarking it against well-established measures of delay discounting. The results highlight the promise and utility of behavioral economic tools for assessing trait and state influences on cognitive motivation.

  13. Evaluation of 80 implants subjected to immediate loading in edentulous mandibles after two years of follow-up.

    Science.gov (United States)

    Martínez-González, Jose María; Barona-Dorado, Cristina; Cano-Sánchez, Jorge; Fernández-Cáliz, Fernando; Sánchez-Turrión, Andrés

    2006-03-01

    An analysis is made of the clinical and radiological behavior of 80 implants with a new surface subjected to etching with a sulfuric and hydrofluoric acid solution followed by thermal treatment, and subjected to immediate loading in patients with lower overdentures. A prospective observational study was made of 20 patients with lower overdentures supported by four implants measuring 13 mm in length. All patients were included after the obtainment of informed consent, anamnesis, clinical examination and radiological study, with prior clinical elaboration of the lower dentures. Over two years of follow-up, no important plaque or tartar accumulation was observed (with Silness and Loe indexes of 0-1). Periodontal probing proved favorable, with no pocket depths of over 2 mm in any case. The radiological controls showed no implant failures during follow-up. No cervical bone loss was recorded in the first year in a large proportion of cases (65%), while reabsorption of the cervical half was observed in 10%, and of three-quarters of the cervical portion in the remaining 35%. Performance in the second year was compatible with the standard references--with losses of between 0.5-1.5 mm. Rehabilitation with lower overdentures should be regarded as a priority indication, and implantological treatment substitution by conventional and/or early resting periods should be considered.

  14. Trunk and pelvic coordination at various walking speeds during an anterior load carriage task in subjects with and without chronic low back pain

    OpenAIRE

    Kim, Tackhoon; Chai, Eunsu

    2015-01-01

    [Purpose] This study compared the coordination patterns of the trunk and pelvis in the transverse plane between healthy subjects and patients with chronic low back pain during an anterior load carriage task at various walking speeds. [Subjects] Ten healthy subjects and 10 patients with chronic low back pain performed an anterior carriage task with a load of 10% body weight at walking speeds of 3.5, 4.5, or 5.5?km/h. [Methods] The trunk and pelvic kinematics were measured by using a motion ana...

  15. Finite element analysis of the lateral load test on battered pile group at I-10 twin span bridge : research project capsule.

    Science.gov (United States)

    2016-04-01

    The objectives of this research study are to develop a three-dimensional FE : model for simulating the behavior of a battered pile group foundation subjected : to lateral loading, and to verify the model using results from a unique static : lateral l...

  16. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading

    Directory of Open Access Journals (Sweden)

    Cao Vu Dung

    2016-04-01

    Full Text Available Polyvinylidene Flouride (PVDF is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental “stress-averaging” mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the “stress-averaging” mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam’s modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor’s output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  17. Longitudinal research on subjective aging, health, and longevity : Current evidence and new directions for research

    NARCIS (Netherlands)

    Westerhof, Gerben J.; Wurm, Susanne

    2015-01-01

    In this chapter, we carry out a narrative review of the longitudinal impact of subjective aging on health and survival. We have a specifi c focus on the different pathways which can explain the relation of subjective aging to health and survival. We focus on the three most common conceptualizations

  18. Finite Element Analysis Examining the Effects of Cam FAI on Hip Joint Mechanical Loading Using Subject-Specific Geometries During Standing and Maximum Squat.

    Science.gov (United States)

    Ng, K C Geoffrey; Rouhi, Gholamreza; Lamontagne, Mario; Beaulé, Paul E

    2012-10-01

    Cam femoroacetabular impingement (FAI) can impose elevated mechanical loading in the hip, potentially leading to an eventual mechanical failure of the joint. Since in vivo data on the pathomechanisms of FAI are limited, it is still unclear how this deformity leads to osteoarthritis. The purpose of this study was to examine the effects of cam FAI on hip joint mechanical loading using finite element analysis, by incorporating subject-specific geometries, kinematics, and kinetics. The research objectives were to address and determine: (1) if hips with cam FAI demonstrate higher maximum shear stresses, in comparison with control hips; (2) the magnitude of the peak maximum shear stresses; and (3) the locations of the peak maximum shear stresses. Using finite element analysis, two patient models were control-matched and simulated during quasi-static positions from standing to squatting. Intersegmental hip forces, from a previous study, were applied to the subject-specific hip geometries, segmented from CT data, to evaluate the maximum shear stresses on the acetabular cartilage and underlying bone. Peak maximum shear stresses were found at the anterosuperior region of the underlying bone during squatting. The peaks at the anterosuperior acetabulum were substantially higher for the patients (15.2 ± 1.8 MPa) in comparison with the controls (4.5 ± 0.1 MPa). Peaks were not situated on the cartilage, but instead located on the underlying bone. The results correspond with the locations of initial cartilage degradation observed during surgical treatment and from MRI. These findings support the pathomechanism of cam FAI. Changes may originate from the underlying subchondral bone properties rather than direct shear stresses to the articular cartilage.

  19. Buckling loads for stiffened panels subjected to combined longitudinal compression and shear loadings: Results obtained with PASCO, EAL, and STAGS computer

    Science.gov (United States)

    Stroud, W. J.; Greene, W. H.; Anderson, M. S.

    1981-01-01

    The shear buckling analyses used in PASCO are summarized. The PASCO analyses include the basic VIPASA analysis, which is essentially exact for longitudinal and transverse loads, and a smeared orthotropic solution which was added to alleviate a shortcoming in the VIPASA analysis. Buckling results are presented for six stiffened panels loaded by combinations of longitudinal compression and shear. The buckling results were obtained with the PASCO, EAL, and STAGS computer programs. The EAL and STAGS solutions were obtained with a fine finite element mesh and provide calculations for the entire range of combinations of longitudinal compression and shear loadings.

  20. Hans Jonas' thought on the ethics of research on human subjects

    African Journals Online (AJOL)

    Dr Olaleye

    The thinking and teachings of Hans Jonas was on the need for medical research to advance beyond the use animals for research and experimentations to research on human subjects. Jonas upholds the established view that medicine is an experimental science and that most medical advances are product of trial and error ...

  1. Hans Jonas' thought on the ethics of research on human subjects ...

    African Journals Online (AJOL)

    The thinking and teachings of Hans Jonas was on the need for medical research to advance beyond the use animals for research and experimentations to research on human subjects. Jonas upholds the established view that medicine is an experimental science and that most medical advances are product of trial and error ...

  2. The Role of Subjectivity in Teacher Expertise Development: Mindfully Embracing the "Black Sheep" of Educational Research

    Science.gov (United States)

    Inoue, Noriyuki

    2016-01-01

    In Western cultures, subjectivity has often been seen as the "black sheep" of educational research because of its heavy emphasis on objectivity. Consequently many research initiatives in education share the assumption that objective reasoning should play a central role. However, mentoring teachers' practice improvement research often…

  3. Experimental study on energy absorption of foam filled kraft paper honeycomb subjected to quasi-static uniform compression loading

    Science.gov (United States)

    Abd Kadir, N.; Aminanda, Y.; Ibrahim, M. S.; Mokhtar, H.

    2016-10-01

    A statistical analysis was performed to evaluate the effect of factor and to obtain the optimum configuration of Kraft paper honeycomb. The factors considered in this study include density of paper, thickness of paper and cell size of honeycomb. Based on three level factorial design, two-factor interaction model (2FI) was developed to correlate the factors with specific energy absorption and specific compression strength. From the analysis of variance (ANOVA), the most influential factor on responses and the optimum configuration was identified. After that, Kraft paper honeycomb with optimum configuration is used to fabricate foam-filled paper honeycomb with five different densities of polyurethane foam as filler (31.8, 32.7, 44.5, 45.7, 52 kg/m3). The foam-filled paper honeycomb is subjected to quasi-static compression loading. Failure mechanism of the foam-filled honeycomb was identified, analyzed and compared with the unfilled paper honeycomb. The peak force and energy absorption capability of foam-filled paper honeycomb are increased up to 32% and 30%, respectively, compared to the summation of individual components.

  4. Coupled RELAP5, 3D CFD and FEM analysis of postulated cracks in RPVs subjected to PTS loading

    Energy Technology Data Exchange (ETDEWEB)

    González-Albuixech, V.F., E-mail: vicente.gonzalez@psi.ch [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Qian, G., E-mail: guian.qian@psi.ch [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Sharabi, M. [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland); Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, 35516 Mansoura (Egypt); Niffenegger, M.; Niceno, B.; Lafferty, N. [Paul Scherrer Institut (PSI), Nuclear Energy and Safety Department, Structural Integrity Group, Villigen CH-5232 (Switzerland)

    2016-02-15

    Highlights: • RPV fracture mechanics model based on RELAP5. • RPV fracture mechanics model based on CFD. • RPV fracture mechanics analysis. - Abstract: The fracture mechanic analysis of a reactor pressure vessel subjected to pressurized thermal shock loading is one of the most important issues for the assessment of life time extension of a nuclear power plant. The most severe scenario occurs during cold water injection in the cold leg due to a Loss-Of-Coolant Accident (LOCA). In the present study a comprehensive fracture mechanics analysis is performed. Two hypothetical LOCAs are assumed for an adopted reference design of a two-loop Pressurized Water Reactor. Boundary conditions obtained from the RELAP5 code are used as input for Computational Fluid Dynamics (CFD) simulations. For the structural integrity analysis, submodeling technique and the eXtended Finite Element Method (XFEM) based on temperatures calculated by CFD are applied. The results from the 3D FEM calculations are compared to those from a simplified axisymmetric model based on axisymmetric thermal hydraulic model results. The analysis identifies the worst crack orientation and location. It also proves that a complete model is needed for a correct analysis as the simplified model is not conservative and fails to describe accurately the local plume effect.

  5. Fracture Mechanics Analyses of Subsurface Defects in Reinforced Carbon-Carbon Joggles Subjected to Thermo-Mechanical Loads

    Science.gov (United States)

    Knight, Norman F., Jr.; Raju, Ivatury S.; Song, Kyongchan

    2011-01-01

    Coating spallation events have been observed along the slip-side joggle region of the Space Shuttle Orbiter wing-leading-edge panels. One potential contributor to the spallation event is a pressure build up within subsurface voids or defects due to volatiles or water vapor entrapped during fabrication, refurbishment, or normal operational use. The influence of entrapped pressure on the thermo-mechanical fracture-mechanics response of reinforced carbon-carbon with subsurface defects is studied. Plane-strain simulations with embedded subsurface defects are performed to characterize the fracture mechanics response for a given defect length when subjected to combined elevated-temperature and subsurface-defect pressure loadings to simulate the unvented defect condition. Various subsurface defect locations of a fixed-length substrate defect are examined for elevated temperature conditions. Fracture mechanics results suggest that entrapped pressure combined with local elevated temperatures have the potential to cause subsurface defect growth and possibly contribute to further material separation or even spallation. For this anomaly to occur, several unusual circumstances would be required making such an outcome unlikely but plausible.

  6. Experimental Investigation of Dynamic Response and Deformation of Aluminium Honeycomb Sandwich Panels Subjected to Underwater Impulsive Loads

    Directory of Open Access Journals (Sweden)

    Da-Lin Xiang

    2015-01-01

    Full Text Available The response of aluminium sandwich panels with three thicknesses’ core subjected to different underwater loading levels has been studied in the fluid-structure interaction (FSI experiments. The transient response of the panels is measured using a three-dimensional (3D Digital Image Correlation (DIC system, along with high-speed photography. The full-field shape and displacement profiles of dry face sheets were recorded in real time compared with those of monolithic plate. The out-of-plane deflection and in-plane strain were quantified and analyzed. Three typical deformation modes of sandwich panel were identified. The results show that the core structure is crushed resulting in an initial large circular shape of deformation in the center area of panels. From this moment on, the panel is starting to act as a free vibration beam with initial velocities. The deformation modes consisted of homogeneous large deformation for both face sheets, obvious deformation border on wet face sheet, core node imprinting, remarkable wrinkled skin of deformation border, and a partial delamination and partial tear failure of the dry face. The blast-resistance of sandwich panel can be highly efficiently improved by increasing the thickness of core structure.

  7. Fatigue life prediction in a unidirectional glass-epoxy composite material subjected to off-axis cyclic loads

    Directory of Open Access Journals (Sweden)

    Revuelta, D.

    2005-03-01

    Full Text Available Most of today s fatigue analysis and design methods for composite laminates were developed primarily on the basis of experience with homogeneous metals. Such methods are subject to serious drawbacks, however, because the failure the modes of failure observed in metals. A theoretical model for predicting the fatigue life of continuous glass-fibre/epoxy composite materials under general loading conditions has been developed on the basis of fundamental fatigue failure modes and local failure criteria.

    La mayoría de los actuales métodos de cálculo y diseño a fatiga de estructuras de materiales compuestos se han desarrollado principalmente a partir de la experiencia previa en materiales metálicos homogéneos. Sin embargo, estos métodos presentan serios inconvenientes debido a que la heterogeneidad y micro estructura orientada características de los materiales compuestos laminados provocan modos de fallo diferentes a los de los metales. Basándose en los modos fundamentales de rotura por fatiga y en criterios de rotura local, se desarrolla un modelo teórico de vida a fatiga para materiales compuestos de matriz epoxi reforzados con fibra de vidrio bajo condiciones generales de carga

  8. COGNITIVE LOAD MEASUREMENT WITHIN THE RESEARCH OF EFFICIENT USAGE OF LEARNING SOFTWARE

    Directory of Open Access Journals (Sweden)

    Tetiana M. Derkach

    2011-05-01

    Full Text Available The methods of cognitive load measurement are described within the research of efficient usage of learning Software. Their classification is given, main advantages and disadvantages are analyzed, as well as area of use of these methods is defined. The article presents an overview of modern Software and Hardware that can be used for cognitive load measurement while studying with information technologies and practical examples of such methods. The use of the secondary task method is reasoned to be the most optimal for cognitive load measurement as well as for detection of optimal conditions for student work with different learning materials. This method allows to receive objective quantification of cognitive load and to investigate its dynamics accurately.

  9. Emerging Evidence from Single-Subject Research in the Field of Deaf-Blindness

    Science.gov (United States)

    Parker, Amy T.; Davidson, Roseanna; Banda, Devender R.

    2007-01-01

    Professionals in the field of deaf-blindness are challenged to use instructional practices that have been tested using experimental methodology. Single-subject design has been examined as a form of research that assists in substantiating practice. In a review of the literature, the authors identified 54 single-subject studies from 1969 to 2006…

  10. Studies Using Single-Subject Designs in Sport Psychology: 30 Years of Research

    Science.gov (United States)

    Martin, G. L.; Thompson, K.; Regehr, K.

    2004-01-01

    A prominent feature of behavior-analytic research has been the use of single-subject designs. We examined sport psychology journals and behavioral journals published during the past 30 years, and located 40 studies using single-subject designs to assess interventions for enhancing the performance of athletes and coaches. In this paper, we…

  11. A method to evaluate performance reliability of individual subjects in laboratory research applied to work settings.

    Science.gov (United States)

    1978-10-01

    This report presents a method that may be used to evaluate the reliability of performance of individual subjects, particularly in applied laboratory research. The method is based on analysis of variance of a tasks-by-subjects data matrix, with all sc...

  12. A 15-Year Review of Trends in Representation of Female Subjects in Islamic Bioethics Research.

    Science.gov (United States)

    Hussain, Zeenat; Kuzian, Edyta; Hussain, Naveed

    2017-02-01

    Gender representation in Islamic bioethics research in the twenty-first century has not been studied. To study temporal trends in representation of female subjects in Islamic bioethics research, PubMed-listed publications on Islamic bioethics from years 2000 to 2014 were reviewed for gender participation in human subjects' research. There were temporal trends of increasing publications of Islamic bioethics-related human subjects' research (64 papers over 15 years; R (2) = 0.72; p < 0.0004). Female subjects were well represented with a trend toward increasing participation. This was true for women from Muslim-majority countries even in non-gender-focused studies over the past 15 years.

  13. The effect of integrating constructivist and evidence-based practice on baccalaureate nursing student's cognitive load and learning performance in a research course.

    Science.gov (United States)

    Hsieh, Suh-Ing; Hsu, Li-Ling; Huang, Tzu-Hsin

    2016-07-01

    Baccalaureate nursing students perceive research as unattractive, doubt the value of nursing research, and do not appreciate the link of research with practice. No studies have examined students' cognitive load during an evidence-based practice research course versus a traditional research course. To assess the effect of integrating constructivist theories and evidence-based practice on student cognitive load and learning performance in a research course. A true experimental study. A Registered Nurse-to-Bachelor of Science in Nursing program. Six classes of second-year students. Students were randomly allocated to the control group (two classes) or the experimental group (two classes) using cluster randomization. The control group underwent "traditional research"; the experimental group experienced "integrating evidence-based practice into research." Instruments for outcome assessment include the Cognitive Load Scale, cognitive test, team critique paper, and qualitative feedback on course satisfaction. The between-subjects effects were compared by Analysis of Covariance. The experimental group had significantly higher mental load (8.74 vs. 7.27, presearch knowledge (70.61 vs. 44.92, pwriting (89.40%). Some experimental learners expressed satisfaction with learning evidence-based practice (17.78%) and critiquing a research article (7.78%). Integrating evidence-based practice into a research course not only improved the research knowledge of baccalaureate nursing students, but also increased their mental load, mental effort, and mental efficiency. Additional studies may track learners' responses to different learning systems using the developed instrument to measure the three types of cognitive load. These findings may help educators design more effective and interesting curricula for integrating research and evidence-based practice into the studies of student nurses. Copyright © 2016. Published by Elsevier Ltd.

  14. The use of a constant load to generate equivalent viscoelastic strain in finite element analysis of cemented prosthetic joints subjected to cyclic loading.

    Science.gov (United States)

    Lu, Z; McKellop, H A

    2011-08-01

    Polymers such as polymethyl-methacrylate (PMMA) surgical cement undergo elastic and viscoelastic deformation (creep) in response to physiological cyclic loading. Theoretically, the effect of gradual creep deformation on the stresses, strains, and displacements of a prosthetic joint can be evaluated by running a finite element analysis (FEA) model through a large number of loading cycles. However, with complex (i.e. realistic) models, this approach may require extensive computational time, and may accumulate unacceptably large numerical errors over the many iterations of the model. The present study utilized a Fourier series to represent a periodic stress and incorporated it in the linear viscoelastic constitutive equation. It was demonstrated that, for a linear viscoelastic material, the time average (i.e. the constant in the Fourier series) of the cyclic stress determined the accumulated creep strain and the sinusoidal components of the stress produced the periodic creep strain with a zero average and negligible amplitude. For a geometrically linear FEA model, the solution based on a cyclic stress can be readily applied to an external cyclic load, that is, the creep strain is determined by the time average of the cyclic load. While femoral component models were considered as geometrically non-linear, an FEA model of a femur implanted with an Exeter hip prosthesis showed that there was only a minor difference between the profile of the applied sinusoidal load and that of the resulting displacement. In such cases, applying the time average of a cyclic load to calculate the resulting creep strain with a given duration of loading should expect to provide acceptable accuracy, with a marked reduction in the computational time.

  15. Cancer fear and fatalism: how African American participants construct the role of research subject in relation to clinical cancer research.

    Science.gov (United States)

    Somayaji, Darryl; Cloyes, Kristin Gates

    2015-01-01

    Lack of African American participation in cancer clinical trials has been identified as a critical problem. Historical interactions related to race, identity, and power may contribute to continued inequity in healthcare and research participation. The aim of this study was to explore the perceptions of African Americans regarding cancer and research and how these perceptions shape their beliefs about participating as cancer research subjects. Three African American focus groups were conducted including people who had never participated in cancer research, those who had, and those who were asked but refused (n = 16). Discussion focused on their perceptions of cancer research and actual or potential participation as research subjects. Data were coded using both structured and inductive coding methods. Fear and fatalism emerged in relation to research, race, power, and identity and were related to larger historical and social issues rather than only individual thoughts or feelings. Participants described fears of the unknown, death, mistrust, conspiracy, and discrimination together with positive/negative tensions between self, family, and community responsibilities. Complex identities linked perceptions of cancer and cancer research with broader historical and cultural issues. Fear, fatalism, and current and historical relationships influence how people perceive themselves as research subjects and may influence their decisions to participate in cancer research. Acknowledging how complex factors including race and racism contribute to health disparities may give nurses and other healthcare providers a better appreciation of how historical, social, and cultural dynamics at individual, community, and organizational levels influence access to and participation in cancer research.

  16. Ethics in action: Approving and improving medical research with human subjects

    OpenAIRE

    de Jong, J.P.

    2013-01-01

    In this thesis, Jean Philippe de Jong presents a new understanding of ethical oversight on medical research with human subjects and proposes that two philosophies for ethical oversight exist: '(dis)approving' and 'improving'. Systems for ethical oversight on medical research have been in place for many years, with Research Ethics Committees as their cornerstone. Although these oversight systems aim to ensure that the ethical quality of research is in order, they have been criticized for imped...

  17. Research in the hospital setting on human subjects. Protecting the patient and the institution.

    Science.gov (United States)

    Scheuer, R

    1993-10-01

    A hospital's institutional review board is charged with the responsibility of fully protecting the rights of research subjects. In doing so, the board establishes that research protocols are based on sound scientific principles, that benefits to research subjects outweigh the risks, and that the subject's consent is informed and not coerced. Although it has been argued that risk management has no role in the activities of such boards, the literature indicates that risk management and quality assurance principles apply to all areas of the institution, including the activities of the board. The institution must ensure that its researchers and board members are as fully protected as possible from civil and criminal liability and that the integrity of those conducting the research is established and maintained. The institution must also provide sufficient support for the board to conduct its reviews and educate the research community and board members on current and evolving laws and regulations governing human research. Risk prevention and quality assurance strategies should recognize the rights of the research subject as paramount while protecting the institution, its researchers, and the community served.

  18. The Research on Coordinated Decision-Making Method Tax System Based on Subject Data

    Directory of Open Access Journals (Sweden)

    Zhaoji Yu

    2015-01-01

    Full Text Available Academically, the research of subject database of tax system aims to set up an efficient, harmonious virtual data application environment. Subject data, in application and management, has been on demand polymerized and autonomously collaborated and has reached a balance between instantaneity and accuracy. This paper defines the connotation and characteristics enterprise informationization, designs a value system of enterprise informationization which is subject database oriented, and builds a model for the import of the subject database of enterprise informationization. Meantime, this paper describes the structure of the subject database based information import model and forges the model’s theoretical basis of subject data import in tax system. Using the model can make an analysis on the information of data warehouse, storage information, and tax information to provide decision support for the tax administrators.

  19. Contemporary cognitive load theory research: The good, the bad and the ugly

    NARCIS (Netherlands)

    Kirschner, Paul A.; Ayres, Paul; Chandler, Paul

    2010-01-01

    Kirschner, P. A., Ayres, P., & Chandler, P. (2011). Contemporary cognitive load theory research: The good, the bad and the ugly. Computers in Human Behavior, 27(1), 99-105. doi:10.1016/j.chb.2010.06.025

  20. Effects of glycemic load on metabolic risk markers in subjects at increased risk of developing metabolic syndrome.

    Science.gov (United States)

    Vrolix, Ruth; Mensink, Ronald P

    2010-08-01

    Epidemiologic studies suggest that diets with a low glycemic index (GI) or glycemic load (GL) are associated with a decreased risk of developing metabolic syndrome. Intervention studies are inconsistent, however, possibly due to differences in macronutrient and fiber compositions of the experimental diets. We tested side-by-side test foods with similar macronutrient and fiber compositions but with different sucrose-flour ratios or carbohydrate source to determine the effects of different GIs and GLs on metabolic risk markers in overweight subjects. Overweight men (n = 9) and women (n = 6) received in random order for 11 wk 4 test foods with an increased GI or a decreased GI (69 compared with 40, 86 compared with 48, 63 compared with 37, and 51 compared with 20, respectively). There was a GL difference of 32 units between the 2 interventions. At the end of the 11-wk intervention periods, the decreased GL test foods did not change fasting plasma glucose (mean +/- SD: 5.83 +/- 0.6 compared with 5.94 +/- 0.6 mmol/L) or insulin (8.3 +/- 2.8 compared with 9.8 +/- 5.1 mU/L) concentrations compared with increased GL test foods. Serum total cholesterol (5.56 +/- 0.90 compared with 5.76 +/- 1.04 mmol/L), LDL-cholesterol (3.57 +/- 0.72 compared with 3.68 +/- 0.80 mmol/L), HDL-cholesterol (1.21 +/- 0.38 compared with 1.24 +/- 0.37 mmol/L), and triacylglycerol (1.61 +/- 0.77 compared with 1.78 +/- 1.04 mmol/L) concentrations were also not significantly different for decreased and increased GL test foods, respectively. Finally, proinflammatory (high-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha, monocyte chemoattractant protein 1) and prothrombotic (plasminogen activator inhibitor 1) markers were not affected. Glucose and lipids were also analyzed after 1 and 5 wk of intervention and were not affected by the intervention. When incorporated into a habitual diet, consumption of test foods with a decreased GL does not ameliorate metabolic risk markers

  1. Profiles of Urine Drug Test in Clinical Pain Patients vs Pain Research Study Subjects.

    Science.gov (United States)

    Lee, Cheng-ting; Vo, Trang T; Cohen, Abigail S; Ahmed, Shihab; Zhang, Yi; Mao, Jianren; Chen, Lucy

    2016-04-01

    To examine similarities and differences in urine drug test (UDT) results in clinical pain patients and pain subjects participating in pain research studies. An observational study with retrospective chart review and data analysis. We analyzed 1,874 UDT results obtained from 1) clinical pain patients (Clinical Group; n = 1,529) and 2) pain subjects consented to participate in pain research studies (Research Group; n = 345). Since several medications such as opioids used in pain management are drugs of abuse (DOA) and can result in a positive UDT, we specifically identified those cases of positive UDT due to nonprescribed DOA and designated these cases as positive UDT with DOA (PUD). We found that 1) there was a higher rate of PUD in clinical pain patients (41.3%) than in pain research study subjects (14.8%); 2) although subjects in the Research Group were informed ahead of time that UDT will be conducted as a screening test, a substantial number (14.8%) of pain research study subjects still showed PUD; 3) there were different types of DOA between clinical pain patients (cannabinoids as the top DOA) and research study subjects (cocaine as the top DOA); and 4) a common factor associated with PUD was opioid therapy in both Clinical Group and Research Group. These results support previous findings that PUD is a common finding in clinical pain patients, particularly in those prescribed opioid therapy, and we suggest that UDT be used as routine screening testing in pain research studies. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Single-subject research design: recommendations for levels of evidence and quality rating.

    Science.gov (United States)

    Romeiser Logan, Lynne; Hickman, Robbin R; Harris, Susan R; Heriza, Carolyn B

    2008-02-01

    The aim of this article is to present a set of evidence levels, accompanied by 14 quality or rigor questions, to foster a critical review of published single-subject research articles. In developing these guidelines, we reviewed levels of evidence and quality/rigor criteria that are in wide use for group research designs, e.g. randomized controlled trials, such as those developed by the Treatment Outcomes Committee of the American Academy for Cerebral Palsy and Developmental Medicine. We also reviewed methodological articles on how to conduct and critically evaluate single-subject research designs (SSRDs). We then subjected the quality questions to interrater agreement testing and refined them until acceptable agreement was reached. We recommend that these guidelines be implemented by clinical researchers who plan to conduct single-subject research or who incorporate SSRD studies into systematic reviews, and by clinicians who aim to practise evidence-based medicine and who wish to critically review pediatric single-subject research.

  3. Identifying Evidence-Based Special Education Interventions from Single-Subject Research

    Science.gov (United States)

    Freeman, Jennifer; Sugai, George

    2013-01-01

    Special educators are required to use evidence-based academic and behavioral interventions in their classrooms (U.S. Department of Education, 2010). No rigorous and comprehensive database currently exists to support educators. Within the field of special education, single-subject research is the primary research methodology (Horner, Carr, Halle,…

  4. "Biosphere Reserve"--The Actual Research Subject of the Sustainable Development Process"

    Science.gov (United States)

    Khasaev, Gabibulla R.; Sadovenko, Marina Yu.; Isaev, Roman O.

    2016-01-01

    The relevance of the analyzed issue is caused by the growing slippage of research funds of sustainable development in its practice. The purpose of the article is the theoretical basis of the biosphere reserve as a scientific research subject that is relevant to rules of the scientific activity. The leading approach to the study of this issue is…

  5. Use of the single subject design for practice based primary care research

    OpenAIRE

    Janosky, J.

    2005-01-01

    The use of a single subject research design is proposed for practice based primary care research. An overview of the rationale of the design, an introduction to the methodology, strengths, limitations, a sample of recent literature citations, a working example, and possible clinical applications are presented.

  6. Ethics in action: Approving and improving medical research with human subjects

    NARCIS (Netherlands)

    de Jong, J.P.

    2013-01-01

    In this thesis, Jean Philippe de Jong presents a new understanding of ethical oversight on medical research with human subjects and proposes that two philosophies for ethical oversight exist: '(dis)approving' and 'improving'. Systems for ethical oversight on medical research have been in place for

  7. The self as subject autoethnographic research into identity, culture, and academic librarianship

    CERN Document Server

    Deitering, Anne-Marie; Stoddart, Richard

    2017-01-01

    Using autoethnography as their research method, the 21 academic librarian authors of The Self as Subject: Autoethnographic Research into Identity, Culture, and Academic Librarianship investigate aspects of what it means to be a librarian. Starting with a reflective examination of themselves, they each investigate questions of culture, values, and identity. The Self as Subject presents a collection of reflective narratives that, taken together, explore the varied dimensions of librarianship in the present moment. It also examines autoethnography's potential to help librarians answer questions that cannot be answered by traditional, empirical research methods and to reveal voices that are obscured by aggregations of data.

  8. Evaluation of a new methodology to simulate damage and wear of polyethylene hip replacements subjected to edge loading in hip simulator testing.

    Science.gov (United States)

    Partridge, Susan; Tipper, Joanne L; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John; Williams, Sophie

    2017-06-29

    Wear and fatigue of polyethylene acetabular cups have been reported to play a role in the failure of total hip replacements. Hip simulator testing under a wide range of clinically relevant loading conditions is important. Edge loading of hip replacements can occur following impingement under extreme activities and can also occur during normal gait, where there is an offset deficiency and/or joint laxity. This study evaluated a hip simulator method that assessed wear and damage in polyethylene acetabular liners that were subjected to edge loading. The liners tested to evaluate the method were a currently manufactured crosslinked polyethylene acetabular liner and an aged conventional polyethylene acetabular liner. The acetabular liners were tested for 5 million standard walking cycles and following this 5 million walking cycles with edge loading. Edge loading conditions represented a separation of the centers of rotation of the femoral head and the acetabular liner during the swing phase, leading to loading of the liner rim on heel strike. Rim damage and cracking was observed in the aged conventional polyethylene liner. Steady-state wear rates assessed gravimetrically were lower under edge loading compared to standard loading. This study supports previous clinical findings that edge loading may cause rim cracking in liners, where component positioning is suboptimal or where material degradation is present. The simulation method developed has the potential to be used in the future to test the effect of aging and different levels of severity of edge loading on a range of cross-linked polyethylene materials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  9. Low diagnostic value of fasting and post-methionine load homocysteine tests. A study in Dutch subjects with homocysteine test indications

    NARCIS (Netherlands)

    Fokkema, M R; Dijck-Brouwer, D A J; van Doormaal, J J; Reijngoud, D J; Muskiet, F A J

    BACKGROUND: Homocysteine is a cardiovascular disease risk factor. We investigated, both in subjects with past plasma total homocysteine (tHcy) test indications and healthy adults, the diagnostic value of a fasting (tHcy) (f-tHcy) and the added value of a post-methionine-load tHcy (postload-tHcy).

  10. Deliberate Microbial Infection Research Reveals Limitations to Current Safety Protections of Healthy Human Subjects.

    Science.gov (United States)

    Evers, David L; Fowler, Carol B; Mason, Jeffrey T; Mimnall, Rebecca K

    2015-08-01

    Here we identify approximately 40,000 healthy human volunteers who were intentionally exposed to infectious pathogens in clinical research studies dating from late World War II to the early 2000s. Microbial challenge experiments continue today under contemporary human subject research requirements. In fact, we estimated 4,000 additional volunteers who were experimentally infected between 2010 and the present day. We examine the risks and benefits of these experiments and present areas for improvement in protections of participants with respect to safety. These are the absence of maximum limits to risk and the potential for institutional review boards to include questionable benefits to subjects and society when weighing the risks and benefits of research protocols. The lack of a duty of medical care by physician-investigators to research subjects is likewise of concern. The transparency of microbial challenge experiments and the safety concerns raised in this work may stimulate further dialogue on the risks to participants of human experimentation.

  11. Experimental assessment and model development of FRP sandwich panels subjected to out-of-plane impact loading

    NARCIS (Netherlands)

    Schipperen, J.H.A.

    2015-01-01

    Fibre reinforced composites are lightweight, strong materials that are increasingly used in all sorts of applications. When loaded in-plane, the material is very strong due to the profitable properties of the fibres. Therefore, the design is normally such that the predominant loading condition is

  12. Growth characteristics of a plane crack subjected to three-dimensional loading. [based on stress intensity factors

    Science.gov (United States)

    Hartranft, R. J.; Sih, G. C.

    1973-01-01

    The closed form expressions for the stress intensity factors due to concentrated forces applied to the surfaces of a half plane crack in an infinite body are used to generate solutions for distributed loads in this geometry. The stress intensity factors for uniformly distributed loads applied over a rectangular portion of the crack surface are given in closed form. An example of non-uniformly distributed loads which can be treated numerically is also included. In particular, combinations of normal and shear stresses on the crack which simulate the case of loading at an angle to the crack front are considered. The resulting stress intensity factors are combined with the strain energy density fracture criterion for the purpose of predicting the most likely direction of crack propagation. The critical value of the energy density factor can then be used for determining the allowable load on a specimen with a crack front not perpendicular to the tensile axis.

  13. Human Subjects Protections in Community-Engaged Research: A Research Ethics Framework1

    Science.gov (United States)

    Ross, Lainie Friedman; Loup, Allan; Nelson, Robert M.; Botkin, Jeffrey R.; Kost, Rhonda; Smith, George R.; Gehlert, Sarah

    2010-01-01

    in the 30 years since the belmont Report, the role of the community in research has evolved and has taken on greater moral significance. Today, more and more translational research is being performed with the active engagement of individuals and communities rather than merely upon them. This engagement requires a critical examination of the range of risks that may arise when communities become partners in research. In attempting to provide such an examination, one must distinguish between established communities (groups that have their own organizational structure and leadership and exist regardless of the research) and unstructured groups (groups that may exist because of a shared trait but do not have defined leadership or internal cohesiveness). In order to participate in research as a community, unstructured groups must develop structure either by external means (by partnering with a Community-Based Organization) or by internal means (by empowering the group to organize and establish structure and leadership). When groups participate in research, one must consider risks to well-being due to process and outcomes. These risks may occur to the individual qua individual, but there are also risks that occur to the individual qua member of a group and also risks that occur to the group qua group. There are also risks to agency, both to the individual and the group. A 3-by-3 grid including 3 categories of risks (risks to well-being secondary to process, risks to well-being secondary to outcome and risks to agency) must be evaluated against the 3 distinct agents: individuals as individual participants, individuals as members of a group (both as participants and as non-participants) and to communities as a whole. This new framework for exploring the risks in community-engaged research can help academic researchers and community partners ensure the mutual respect that community-engaged research requires. PMID:20235860

  14. Validity and reliability of subjective wellbeing indicators in sociological research: The measurement of life satisfaction

    Directory of Open Access Journals (Sweden)

    Mentus Vladimir

    2017-01-01

    Full Text Available The subject of this paper is the level of accuracy i.e. validity and reliability of subjective well-being indicators in sociological research, in case of life satisfaction. First, the relationship between subjective and objective indicators of well-being is presented. Second, the concept of life satisfaction is defined, and the findings of research related to the validity (convergent, discriminant, and predictive and reliability (test-retest, and internal consistency of life satisfaction measures are presented. Third, these findings were reassessed using data originating from large international surveys, which have not been used for this purpose yet. The results in this paper generally contribute to, in quite a large extent existing agreement within the scientific literature about the satisfactory level of validity and reliability of life satisfaction measures i.e. subjective indicators of well-being.

  15. Histologic and histomorphometric evaluation of peri-implant bone subjected to immediate loading: an experimental study with Macaca fascicularis.

    Science.gov (United States)

    Romanos, George E; Toh, Chooi Gait; Siar, Chong Huat; Swaminathan, Dasan

    2002-01-01

    Immediately loaded splinted implants can become osseointegrated when they are placed in the anterior part of the mandible. The concept of immediate loading has not been well examined in the posterior mandible. The aim of this study was to evaluate the hard tissue reactions around immediately loaded implants placed in the posterior mandible in the monkey model. Six adult M. fascicularis monkeys were used in this study. Thirty-six Ankylos implants (Degussa Dental, Hanau-Wolfgang, Germany) were placed after extraction of the second premolar, first, and second molar teeth and complete healing of the sockets. Control (C) group implants were placed and, after osseointegration, were loaded for 1 month using temporary acrylic resin prostheses and later for 2 months using splinted metal crowns. In the contralateral region of the mandible, test (T) group implants were placed and loaded immediately with the same sequence as carried out for the C implants. After sacrifice of the animals, specimens were examined histologically and evaluated histomorphometrically. All implants were osseointegrated. Compact, cortical bone in contact with the implant surface without any gaps or connective tissue formation was demonstrated. Histomorphometric findings of the bone-implant-contacts showed no significant differences between the T and C group implants. Peri-implant mineralized bone areas presented statistically significant differences and showed a higher density of bone between the threads of immediately loaded implants (P < .05). Immediately loaded splinted implants in the posterior mandible can become osseointegrated with a hard tissue peri-implant response similar to that of delayed loaded implants. Moreover, immediate loading seems to increase the ossification of the alveolar bone around endosseous implants.

  16. Growth hormone-releasing effects of whole body vibration alone or combined with squatting plus external load in severely obese female subjects.

    Science.gov (United States)

    Giunta, Marialuisa; Cardinale, Marco; Agosti, Fiorenza; Patrizi, Alessandra; Compri, Emanuele; Rigamonti, Antonello E; Sartorio, Alessandro

    2012-01-01

    Whole body vibration (WBV) has been reported to exert growth hormone(GH)-releasing effects in healthy subjects. Despite the potential of WBV to positively affect body composition changes via lipolytic effects, few studies have been performed in obese subjects to date. This study evaluated the acute effects of WBV alone or in combination with squatting plus external load (WBV+S) on serum GH levels and blood lactate concentrations in 7 severely obese women (age 22 ± 5 years; BMI 39.9 ± 2.9 kg/m2). WBV and WBV+S determined a significant GH increase (mean GH peaks 5.1 ± 1.9 ng/ml, p external load. Further additional studies are required to verify the chronic effects of WBV exercise on the GH/IGF-1 system, which could represent a potentially effective approach for weight management in obese subjects.

  17. A Universal Educational and Research Stand to Simulate Electrical Drive Loading

    Directory of Open Access Journals (Sweden)

    V. S. Grishin

    2016-01-01

    Full Text Available Universal educational and research stand was developed for analyzing an electrical drive’s behavior with different load disturbance effects. Major components of the stand are two electrical drives with rigidly coupled shafts. As a result, first electrical drive (loader has a capability to imitate effects of different loading types to another one (trial drive.Control software for the stand is developed. It allows us to combine a variety of loading types and change parameters of current loading such as joint moment, damping, additional inertia, and external torque. Also there is a capability to imitate effects of elasticity and backlash of mechanical transmissions. The paper considers the main challenge of creating the given system, i.e. discretization with a variable step. Some methods to decrease its negative effects on system stability are suggested.The given system allows to change loading parameters more rapidly and in a wider range as compared to a system with real mechanical outfit.These stands are currently used for laboratory classes within the course “Electrical robotic drives” at SM7 department in Bauman Moscow State Technical University. Also the system of interdepended stands for semi-realistic simulation of manipulation systems is under development.

  18. Where are human subjects in Big Data research? The emerging ethics divide

    Directory of Open Access Journals (Sweden)

    Jacob Metcalf

    2016-06-01

    Full Text Available There are growing discontinuities between the research practices of data science and established tools of research ethics regulation. Some of the core commitments of existing research ethics regulations, such as the distinction between research and practice, cannot be cleanly exported from biomedical research to data science research. Such discontinuities have led some data science practitioners and researchers to move toward rejecting ethics regulations outright. These shifts occur at the same time as a proposal for major revisions to the Common Rule—the primary regulation governing human-subjects research in the USA—is under consideration for the first time in decades. We contextualize these revisions in long-running complaints about regulation of social science research and argue data science should be understood as continuous with social sciences in this regard. The proposed regulations are more flexible and scalable to the methods of non-biomedical research, yet problematically largely exclude data science methods from human-subjects regulation, particularly uses of public datasets. The ethical frameworks for Big Data research are highly contested and in flux, and the potential harms of data science research are unpredictable. We examine several contentious cases of research harms in data science, including the 2014 Facebook emotional contagion study and the 2016 use of geographical data techniques to identify the pseudonymous artist Banksy. To address disputes about application of human-subjects research ethics in data science, critical data studies should offer a historically nuanced theory of “data subjectivity” responsive to the epistemic methods, harms and benefits of data science and commerce.

  19. Subjective soundscapes qualitative research in the experience and evaluation of environmental noise

    Science.gov (United States)

    Flick, Uwe

    2004-05-01

    If the subjective experience and evaluation of environmental noise shall be considered and integrated into the current soundscape research, the use of qualitative research methods used in sociology and psychology will become necessary. A triangulation of research methods for measuring objective noise and for the subjective evaluation of noises and sounds on the background of subjective meanings of health and healthy living will be a fruitful way to a more comprehensive understanding of the phenomenon of soundscapes in the context of health and quality of life. In this contribution, a selection of qualitative research methods will be presented that allows for analyzing subjective experiences with environmental noise. Interviews focusing on narratives of episodes and situations (e.g., the episodic interview, Flick, 2002) will be outlined. Issues of how to assess the quality of qualitative research and its results will be addressed and finally the benefits and limits of the triangulation of different methods (e.g., interviews and focus groups or interviews and physical measures) will be discussed. Research experiences from the author's recent studies on health concepts of health professionals will be used for illustration.

  20. Evaluating Single-Subject Treatment Research: Lessons Learned from the Aphasia Literature

    Science.gov (United States)

    Beeson, Pélagie M.; Robey, Randall R.

    2007-01-01

    The mandate for evidence-based practice has prompted careful consideration of the weight of the scientific evidence regarding the therapeutic value of various clinical treatments. In the field of aphasia, a large number of single-subject research studies have been conducted, providing clinical outcome data that are potentially useful for clinicians and researchers; however, it has been difficult to discern the relative potency of these treatments in a standardized manner. In this paper we describe an approach to quantify treatment outcomes for single-subject research studies using effect sizes. These values provide a means to compare treatment outcomes within and between individuals, as well as to compare the relative strength of various treatments. Effect sizes also can be aggregated in order to conduct meta-analyses of specific treatment approaches. Consideration is given to optimizing research designs and providing adequate data so that the value of treatment research is maximized. PMID:17151940

  1. ANALYTICAL AND NUMERICAL RESEARCH OF WAVE LOADS ON A SHORT VERTICAL WALL

    Directory of Open Access Journals (Sweden)

    Kantarzhi Igor' Grigor'evich

    2012-10-01

    Full Text Available The problem of wave loads on a relatively short wall is related to the issue of the general design of the structure at the stage of its construction, particularly, if the structure is build offshore. The physical nature of interaction between waves and vertical walls that have different lengths is the subject matter of this paper. It is assumed that the wall is absolutely rigid. The comparison of numerical test results and an analytical calculation based on a short wall model is made. As a result, wave forces identified through the employment of the above two models demonstrate their satisfactory convergence. The difference is substantial for longer walls, and it increases along with the increase of the wall length. The conclusion is that a short wall is exposed to the wave load that is not accompanied by any diffraction, therefore, a related method of design may be recommended. Numerical models may be considered as the universal ones.

  2. Practical evaluation of the MiL-Lx lower leg when subjected to simulated vehicle under belly blast load conditions

    CSIR Research Space (South Africa)

    Pandelani, T

    2010-09-01

    Full Text Available show that the Mil-Lx lower leg appears to be robust and is less sensitive to loading method, temperature, Personal Protective Equipment (PPE) and position changes than other lower limb surrogates tested previously....

  3. A comparative analysis of energy dissipation and equivalent viscous damping of RC columns subjected to uniaxial and biaxial loading

    OpenAIRE

    Hugo Rodrigues; Humberto Varum; Antonio Arede; Anibal Costa

    2012-01-01

    The hysteretic behaviour of RC columns has been object of many experimental studies over the past years. However, the majority of these studies are focused on unidirectional loading. An experimental program was carried out where 24 columns were tested for different loading histories, under uniaxial and biaxial conditions. The experimental results are presented in this paper and are discussed in terms of global column behaviour, and particularly with regards to energy dissipation and damping c...

  4. Health Benefits of Animal Research: The Dog as a Research Subject.

    Science.gov (United States)

    Gay, William I.

    1984-01-01

    Discusses the role of dogs in research, considering their use in studies related to: behavior; aging; anesthesia; gastrointestinal surgery; the brain; organ transplants; radiobiology; trauma and shock; arterial diseases; hemophelia; ophthalmology; diabetes; nutrition; cancer; lupus; cyclic neutropenia; thyroiditis; hepatitis; skeletal system,…

  5. Designing oversight for nanomedicine research in human subjects: systematic analysis of exceptional oversight for emerging technologies

    Science.gov (United States)

    Wolf, Susan M.; Jones, Cortney M.

    2011-04-01

    The basic procedures and rules for oversight of U.S. human subjects research have been in place since 1981. Certain types of human subjects research, however, have provoked creation of additional mechanisms and rules beyond the Department of Health & Human Services (DHHS) Common Rule and Food and Drug Administration (FDA) equivalent. Now another emerging domain of human subjects research—nanomedicine—is prompting calls for extra oversight. However, in 30 years of overseeing research on human beings, we have yet to specify what makes a domain of scientific research warrant extra oversight. This failure to systematically evaluate the need for extra measures, the type of extra measures appropriate for different challenges, and the usefulness of those measures hampers efforts to respond appropriately to emerging science such as nanomedicine. This article evaluates the history of extra oversight, extracting lessons for oversight of nanomedicine research in human beings. We argue that a confluence of factors supports the need for extra oversight, including heightened uncertainty regarding risks, fast-evolving science yielding complex and increasingly active materials, likelihood of research on vulnerable participants including cancer patients, and potential risks to others beyond the research participant. We suggest the essential elements of the extra oversight needed.

  6. Designing Oversight for Nanomedicine Research in Human Subjects: Systematic Analysis of Exceptional Oversight for Emerging Technologies

    Science.gov (United States)

    Wolf, Susan M.; Jones, Cortney

    2012-01-01

    The basic procedures and rules for oversight of U.S. human subjects research have been in place since 1981. Certain types of human subjects research, however, have provoked creation of additional mechanisms and rules beyond the Department of Health & Human Services (DHHS) Common Rule and Food and Drug Administration (FDA) equivalent. Now another emerging domain of human subjects research—nanomedicine—is prompting calls for extra oversight. However, in 30 years of overseeing research on human beings, we have yet to specify what makes a domain of scientific research warrant extra oversight. This failure to systematically evaluate the need for extra measures, the type of extra measures appropriate for different challenges, and the usefulness of those measures hampers efforts to respond appropriately to emerging science such as nanomedicine. This article evaluates the history of extra oversight, extracting lessons for oversight of nanomedicine research in human beings. We argue that a confluence of factors supports the need for extra oversight, including heightened uncertainty regarding risks, fast-evolving science yielding complex and increasingly active materials, likelihood of research on vulnerable participants including cancer patients, and potential risks to others beyond the research participant. We suggest the essential elements of the extra oversight needed. PMID:23226969

  7. A generalized modal shock spectra method for spacecraft loads analysis. [internal loads in a spacecraft structure subjected to a dynamic launch environment

    Science.gov (United States)

    Trubert, M.; Salama, M.

    1979-01-01

    Unlike an earlier shock spectra approach, generalization permits an accurate elastic interaction between the spacecraft and launch vehicle to obtain accurate bounds on the spacecraft response and structural loads. In addition, the modal response from a previous launch vehicle transient analysis with or without a dummy spacecraft - is exploited to define a modal impulse as a simple idealization of the actual forcing function. The idealized modal forcing function is then used to derive explicit expressions for an estimate of the bound on the spacecraft structural response and forces. Greater accuracy is achieved with the present method over the earlier shock spectra, while saving much computational effort over the transient analysis.

  8. Dynamic Response of Cable-Supported Façades Subjected to High-Level Air Blast Loads: Numerical Simulations and Mitigation Techniques

    Directory of Open Access Journals (Sweden)

    Claudio Amadio

    2012-01-01

    Full Text Available A glazing façade subjected to blast loads has a structural behaviour that strongly differs from the typical response of a glazing system subjected to ordinary loads. Consequently, sophisticated modelling techniques are required to identify correctly its criticalities. The paper investigates the behaviour of a cable-supported façade subjected to high-level blast loading. Nonlinear dynamic analyses are performed in ABAQUS/Explicit using a sophisticated FE-model (M01, calibrated to dynamic experimental and numerical results. The structural effects of the total design blast impulse, as well as only its positive phase, are analyzed. At the same time, the possible cracking of glass panels is taken into account, since this phenomenon could modify the response of the entire façade. Finally, deep investigations are dedicated to the bearing cables, since subjecting them to elevated axial forces and their collapse could compromise the integrity of the cladding wall. Based on results of previous studies, frictional devices differently applied at their ends are presented to improve the response of the façade under the impact of a high-level explosion. Structural effects of various solutions are highlighted through dynamic simulations. Single vertical devices, if appropriately calibrated, allow reducing significantly the axial forces in cables, and lightly the tensile stresses in glass panes.

  9. UK Library and Information Science Research is Having a Significant Influence on Research in Other Subject Disciplines

    Directory of Open Access Journals (Sweden)

    Mathew Lee Stone

    2014-04-01

    Full Text Available Objective – To quantify the value of librarianship and information science (LIS exports knowledge to other subject disciplines. Design – Bibliometric study. Setting – LIS departments in U.K. universities. Subjects – 232 LIS research articles published between 2001 and 2007. Methods – Data from the 2008 U.K. Research Assessment Exercise were checked to identify 405 research articles submitted by 10 selected university departments (out of a total of 21, which submitted research in the LIS category. The Web of Science database was then searched to see how many of these articles had been cited in other articles (n=232. If the citing article was published in a non-LIS journal it was considered a knowledge export. Journals were defined as non-LIS if they had not been assigned the subject category of Information Science & Library Science by the Journal of Citation Reports. The journal Impact Factors (IFs of citing journals were then normalized to measure the value of individual knowledge exports to their respective subject disciplines. This was done by comparing a citing journal’s IF with the median journal IF within that subject category. If the citing journal’s IF was above this median it was considered to be a valuable knowledge export. Main Results – The sample of LIS research articles produced a total of 1,061 knowledge exports in 444 unique non-LIS journals. These non-LIS journals covered 146 unique subject categories of which those related to computer science and chemistry/pharmacology cited LIS research with the greatest frequency. Just over three-quarters (n=798 of these citations were considered to be valuable knowledge exports. A sub-analysis showed that LIS articles published in non-LIS journals were significantly more valuable than the knowledge exports published in LIS journals. Conclusion – The validity of bibliometric studies can be improved by adopting the two methodological innovations presented in this study. The

  10. Nurse leaders' perceptions of the ethical recruitment of study subjects in clinical research.

    Science.gov (United States)

    Nurmi, Sanna-Maria; Pietilä, Anna-Maija; Kangasniemi, Mari; Halkoaho, Arja

    2015-11-01

    The aim of this study was to describe nurse leaders' perceptions of ethical recruitment in clinical research. Nurse leaders are expected to get involved in clinical research, but there are few studies that focus on their role, particularly the ethical issues. Qualitative data were collected from ten nurse leaders using thematic one-to-one interviews and analysed with content analysis. Nurse leaders considered clinical research at their workplace in relation to the key issues that enabled ethical recruitment of study subjects in clinical research. These were: early information and collaboration for incorporating clinical research in everyday work, an opportune and peaceful recruitment moment and positive research culture. Getting involved in clinical research is part of the nurse leader's professional responsibility in current health care. They have an essential role to play in ensuring that recruitment is ethical and that the dignity of study subjects is maintained. The duty of nurse leaders is to maintain good contact with other collaborators and to ensure good conditions for implementing clinical research at their site. This requires a comprehensive understanding of the overall situation on their wards. Implementing clinical research requires careful planning, together with educating, supporting and motivating nursing staff. © 2014 John Wiley & Sons Ltd.

  11. The case for evidence-based rulemaking in human subjects research.

    Science.gov (United States)

    Sachs, Benjamin

    2010-06-01

    Here I inquire into the status of the rules promulgated in the canonical pronouncements on human subjects research, such as the Declaration of Helsinki and the Belmont Report. The question is whether they are ethical rules or rules of policy. An ethical rule is supposed to accurately reflect the ethical fact (the fact that the action the rule prescribes is ethically obligatory), whereas rules of policy are implemented to achieve a goal. We should be skeptical, I argue, that the actions prescribed by the rules are ethically obligatory, and consequently we should focus our attention on how to craft the rules so as to promote the legitimate goals of human subjects research. Unfortunately, this cannot be done without evidence about the likely effects of various candidate policies-evidence we currently lack. Therefore, we should take the rules as mere starting points, subject to revision as the evidence comes in.

  12. Hierarchical Linear Modeling Meta-Analysis of Single-Subject Design Research

    Science.gov (United States)

    Gage, Nicholas A.; Lewis, Timothy J.

    2014-01-01

    The identification of evidence-based practices continues to provoke issues of disagreement across multiple fields. One area of contention is the role of single-subject design (SSD) research in providing scientific evidence. The debate about SSD's utility centers on three issues: sample size, effect size, and serial dependence. One potential…

  13. Comparison of Nonoverlap Methods for Identifying Treatment Effect in Single-Subject Experimental Research

    Science.gov (United States)

    Rakap, Salih; Snyder, Patricia; Pasia, Cathleen

    2014-01-01

    Debate is occurring about which result interpretation aides focused on examining the experimental effect should be used in single-subject experimental research. In this study, we examined seven nonoverlap methods and compared results using each method to judgments of two visual analysts. The data sources for the present study were 36 studies…

  14. New Findings and Future Directions for Subjective Well-Being Research

    Science.gov (United States)

    Diener, Ed

    2012-01-01

    Recent findings on subjective well-being (SWB) are presented, and I describe the important questions for future research that these raise. Worldwide predictors of SWB such as social support and fulfillment of basic needs have been uncovered, and there are large differences in SWB between societies. A number of culture-specific predictors of SWB…

  15. Implementation of Subjective Probability Estimates in Army Intelligence Procedures: A Critical Review of Research Findings

    Science.gov (United States)

    1980-03-01

    subjective probabil- ity estimates have been incorporated routinely into tactical intelligence comunications . Research in the area of intelligence...analysis: Report on Phase I. Report FSC-71-5047. Gaithersburg, Md.: International Business Machines (IBM), Federal Systems Division, 1971. Kelly, C. W

  16. Reporting of ethical protection in recent oral and maxillofacial surgery research involving human subjects.

    Science.gov (United States)

    Pitak-Arnnop, P; Sader, R; Hervé, C; Dhanuthai, K; Bertrand, J-Ch; Hemprich, A

    2009-07-01

    This retrospective observational study investigated the frequency of reporting ethical approval and informed consent in recently published oral and maxillofacial surgery (OMS) research involving human subjects. All research involving human subjects published in the International Journal of Oral and Maxillofacial Surgery, Journal of Oral and Maxillofacial Surgery, British Journal of Oral and Maxillofacial Surgery, and Journal of Cranio-Maxillofacial Surgery during January to June 2005-2007 were analysed for disclosure of ethical approval by a local ethical committee and obtaining informed consent from the subjects. 534 articles were identified; ethical approval was documented in 118 (22%) and individual patient consent in 135 (25%). 355 reports (67%) did not include a statement on ethical approval or informed consent and only 74 reports (14%) disclosed statements of both. Ethical documentation in retrospective and observational studies was scant; 12% of randomised controlled trials and 38% of non-random trials did not report both of ethical protections. Most recent OMS publications involving humans failed to mention ethical review or subjects' consent. Authors must adhere to the international research ethics guidelines and journal instructions, while editors should play a gatekeeper role to protect research participants, uphold scientific integrity and maintain public trust in the experimental process and OMS profession.

  17. Schrodinger's Cat: Empirical Research into the Radical Subjective solution of the Measurement problem.

    NARCIS (Netherlands)

    Bierman, D.; Whitmarsh, S.

    2007-01-01

    Schrodinger's Cat: Empirical research into the radical subjective solution of the measurement problem Dick J. Bierman & Stephen Whitmarsh The most controversial of all solutions of the measurement problem holds that a measurement is not completed until a conscious observation is made. In other

  18. Research monitoring by US medical institutions to protect human subjects: compliance or quality improvement?

    NARCIS (Netherlands)

    de Jong, Jean Philippe; van Zwieten, Myra C. B.; Willems, Dick L.

    2013-01-01

    In recent years, to protect the rights and welfare of human subjects, institutions in the USA have begun to set up programmes to monitor ongoing medical research. These programmes provide routine, onsite oversight, and thus go beyond existing oversight such as investigating suspected misconduct or

  19. Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates.

    Science.gov (United States)

    Lalander, Cecilia; Dalahmeh, Sahar; Jönsson, Håkan; Vinnerås, Björn

    2013-01-01

    With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2 log10 in the bark filters. The reduction in the virus model organism coliphage phiX174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2 log10 in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal.

  20. Relevant Information and Informed Consent in Research: In Defense of the Subjective Standard of Disclosure.

    Science.gov (United States)

    Dranseika, Vilius; Piasecki, Jan; Waligora, Marcin

    2017-02-01

    In this article, we seek to contribute to the debate on the requirement of disclosure in the context of informed consent for research. We defend the subjective standard of disclosure and describe ways to implement this standard in research practice. We claim that the researcher should make an effort to find out what kinds of information are likely to be relevant for those consenting to research. This invites researchers to take empirical survey information seriously, attempt to understand the cultural context, talk to patients to be better able to understand what can be potentially different concerns and interests prevalent in the target population. The subjective standard of disclosure should be seen as a moral ideal that perhaps can never be perfectly implemented but still can and should be used as a normative ideal guiding research practice. In the light of these discussions, we call for more empirical research on what considerations are likely to be perceived as relevant by potential research participants recruited from different socio-economic and cultural groups.

  1. Coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments

    Science.gov (United States)

    Liu, Yang; Shu, Dong-Wei

    2014-08-01

    Delaminations in structures may significantly reduce the stiffness and strength of the structures and may affect their vibration characteristics. As structural components, beams have been used for various purposes, in many of which beams are often subjected to axial loads and static end moments. In the present study, an analytical solution is developed to study the coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments. Euler-Bernoulli beam theory and the "free mode" assumption in delamination vibration are adopted. This is the first study of the influences of static end moments upon the effects of delaminations on natural frequencies, critical buckling loads and critical moments for lateral instability. The results show that the effects of delamination on reducing natural frequencies, critical buckling load and critical moment for lateral instability are aggravated by the presence of static end moment. In turn, the effects of static end moments on vibration and instability characteristics are affected by the presence of delamination. The analytical results of this study can serve as a benchmark for finite element method and other numerical solutions.

  2. A generalized constitutive elasticity law for GLPD micromorphic materials, with application to the problem of a spherical shell subjected to axisymmetric loading conditions

    Directory of Open Access Journals (Sweden)

    Koffi Enakoutsa

    2014-01-01

    Full Text Available In this work we propose to replace the GLPD hypo-elasticity law by a more rigorous generalized Hooke's law based on classical material symmetry characterization assumptions. This law introduces in addition to the two well-known Lame's moduli, five constitutive constants. An analytical solution is derived for the problem of a spherical shell subjected to axisymmetric loading conditions to illustrate the potential of the proposed generalized Hooke's law.

  3. A generalized constitutive elasticity law for GLPD micromorphic materials, with application to the problem of a spherical shell subjected to axisymmetric loading conditions

    OpenAIRE

    Enakoutsa, Koffi

    2014-01-01

    In this work we propose to replace the GLPD hypo-elasticity law by a more rigorous generalized Hooke's law based on classical material symmetry characterization assumptions. This law introduces in addition to the two well-known Lame's moduli, five constitutive constants. An analytical solution is derived for the problem of a spherical shell subjected to axisymmetric loading conditions to illustrate the potential of the proposed generalized Hooke's law.

  4. Bone reactions adjacent to titanium implants subjected to static load of different duration. A study in the dog (III)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    The aim of the present experiment was to study the effect of a long-standing lateral static load on the peri-implant bone. Three beagle dogs were used. The mandibular premolars were extracted and 12 weeks later 3 titanium implants (ITI(R) Dental Implant System) were installed in each quadrant...

  5. Structural analysis of tree trunks and branches: tapered cantilever beams subject to large deflections under complex loading.

    Science.gov (United States)

    Morgan, J; Cannell, M G

    1987-12-01

    The dimensions, deflections and support costs of tree trunks and branches can be deduced using the structural theory for cantilever beams. However, elementary theory applies only as long as deflections are small, and complex analytical solutions are required to account for complex taper and patterns of loading. This paper describes a method that copes with large deflections, any patterns of taper, and any patterns of distributed loading, point loading or externally applied bending moments. A beam is considered to be composed of a series of short segments, such that each has only a small deflection, and each can have specified dimensions, Young's modulus and loading. The transport matrix method of structural analysis is used to determine the end conditions of each segment and of the whole beam. The method is verified by comparing predicted deflections with deflections (a) calculated using an analytical solution by Bisshopp and Drucker (1945), (b) calculated and measured for sapling tree trunks by Leiser and Kemper (1968), and (c) measured on tapered and untapered plastic rods.

  6. Reflexivity and the "Acting Subject": Conceptualizing the Unit of Analysis in Qualitative Health Research.

    Science.gov (United States)

    Shaw, James A

    2016-07-06

    The ways in which social scientists conceptualize the "reflexive" human subject have important consequences for how we go about our research. Whether and how we understand human subjects to be the authors of our own actions helps to structure what we say about health, health care, and the many other topics addressed in qualitative health research. In this article, I critically discuss assumptions of human reflexivity that are built into qualitative social science of health and medicine. I describe three alternative ways of understanding reflexive thought and human action derived from the theoretical works of Pierre Bourdieu, Bruno Latour, and George Lakoff and Mark Johnson, respectively. I then apply these three different ways of thinking about reflexivity and the acting subject to the analysis of an excerpt of participant observation data from a health services research study of transitions from hospital to home, illuminating the different kinds of analyses that arise from each perspective. I conclude with a call for social scientists to commit to the search for better ways of understanding the human subject, resisting the temptation to "settle" on theoretical statements that close down the path to more sophisticated conceptualizations of human thought and action. © The Author(s) 2016.

  7. The persistence of the subjective in neuropsychopharmacology: observations of contemporary hallucinogen research.

    Science.gov (United States)

    Langlitz, Nicolas

    2010-01-01

    The elimination of subjectivity through brain research and the replacement of so-called "folk psychology" by a neuroscientifically enlightened worldview and self-conception has been both hoped for and feared. But this cultural revolution is still pending. Based on nine months of fieldwork on the revival of hallucinogen research since the "Decade of the Brain," this paper examines how subjective experience appears as epistemic object and practical problem in a psychopharmacological laboratory. In the quest for neural correlates of (drug-induced altered states of) consciousness, introspective accounts of test subjects play a crucial role in neuroimaging studies. Firsthand knowledge of the drugs' flamboyant effects provides researchers with a personal knowledge not communicated in scientific publications, but key to the conduct of their experiments. In many cases, the "psychedelic experience" draws scientists into the field and continues to inspire their self-image and way of life. By exploring these domains the paper points to a persistence of the subjective in contemporary neuropsychopharmacology.

  8. The Patient-Worker: A Model for Human Research Subjects and Gestational Surrogates.

    Science.gov (United States)

    Ryman, Emma; Fulfer, Katy

    2017-01-13

    We propose the 'patient-worker' as a theoretical construct that responds to moral problems that arise with the globalization of healthcare and medical research. The patient-worker model recognizes that some participants in global medical industries are workers and are owed worker's rights. Further, these participants are patient-like insofar as they are beneficiaries of fiduciary relationships with healthcare professionals. We apply the patient-worker model to human subjects research and commercial gestational surrogacy. In human subjects research, subjects are usually characterized as either patients or as workers. Through questioning this dichotomy, we argue that some subject populations fit into both categories. With respect to commercial surrogacy, we enrich feminist discussions of embodied labor by describing how surrogates are beneficiaries of fiduciary obligations. They are not just workers, but patient-workers. Through these applications, the patient-worker model offers a helpful normative framework for exploring what globalized medical industries owe to the individuals who bear the bodily burdens of medical innovation. © 2017 John Wiley & Sons Ltd.

  9. Full-scale testing and numerical modeling of a multistory masonry structure subjected to internal blast loading

    Science.gov (United States)

    Zapata, Brian Jarvis

    As military and diplomatic representatives of the United States are deployed throughout the world, they must frequently make use of local, existing facilities; it is inevitable that some of these will be load bearing unreinforced masonry (URM) structures. Although generally suitable for conventional design loads, load bearing URM presents a unique hazard, with respect to collapse, when exposed to blast loading. There is therefore a need to study the blast resistance of load bearing URM construction in order to better protect US citizens assigned to dangerous locales. To address this, the Department of Civil and Environmental Engineering at the University of North Carolina at Charlotte conducted three blast tests inside a decommissioned, coal-fired, power plant prior to its scheduled demolition. The power plant's walls were constructed of URM and provided an excellent opportunity to study the response of URM walls in-situ. Post-test analytical studies investigated the ability of existing blast load prediction methodologies to model the case of a cylindrical charge with a low height of burst. It was found that even for the relatively simple blast chamber geometries of these tests, simplified analysis methods predicted blast impulses with an average net error of 22%. The study suggested that existing simplified analysis methods would benefit from additional development to better predict blast loads from cylinders detonated near the ground's surface. A hydrocode, CTH, was also used to perform two and three-dimensional simulations of the blast events. In order to use the hydrocode, Jones Wilkins Lee (JWL) equation of state (EOS) coefficients were developed for the experiment's Unimax dynamite charges; a novel energy-scaling technique was developed which permits the derivation of new JWL coefficients from an existing coefficient set. The hydrocode simulations were able to simulate blast impulses with an average absolute error of 34.5%. Moreover, the hydrocode simulations

  10. Fracture morphologies of carbon-black-loaded SBR (styrene-butadiene rubber) subjected to low-cycle, high-stress fatigue. [Styrene-butadiene rubber

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, A.; Lesuer, D.R.; Patt, J.

    1988-02-01

    Experimental results, together with an analytical model, related to the loss in tensile strength of styrene-butadiene rubber (SBR) loaded with carbon black (CB) that had been subjected to low-cycle, high-stress fatigue tests were presented in a prior paper. The drop in tensile strength relative to that of a virgin sample was considered to be a measure of damage induced during the fatigue test. The present paper is a continuation of this study dealing with the morphological interpretations of the fractured surfaces, whereby the cyclic-tearing behavior, resulting in the damage, is related to the test and material parameters. It was found that failure is almost always initiated in the bulk of a sample at a material flaw. The size and definition of a flaw increase with an increase in carbon-black loading. Initiation flaw sites are enveloped by fan-shaped or penny-shaped regions which develop during cycling. The size and morphology of a fatigue-tear region appears to be independent of the fatigue load or the extent of the damage (strength loss). By contrast, either an increase in cycling load or an increase in damage at constant load increases the definition of the fatigue-region morphology for all formulations of carbon-black. On the finest scale, the morphology can be described in terms of tearing of individual groups of rubber strands, collapsing to form a cell-like structure. 18 refs., 13 figs.

  11. Time-domain parameter identification of aeroelastic loads by forced-vibration method for response of flexible structures subject to transient wind

    Science.gov (United States)

    Cao, Bochao

    research, new algorithms were developed based on forced vibration technique for direct extraction of the Rational Functions. The first of the two algorithms developed uses the two angular phase lag values between the measured vertical or torsional displacement and the measured aerodynamic lift and moment produced on the section model subject to forced vibration to identify the Rational Functions. This algorithm uses two separate one-degree-of-freedom tests (vertical or torsional) to identify all the four Rational Functions or corresponding Rational Function Coefficients for a two degrees-of-freedom (DOF) vertical-torsional vibration model. It was applied to a streamlined section model and the results compared well with those obtained from earlier free vibration experiment. The second algorithm that was developed is based on direct least squares method. It uses all the data points of displacements and aerodynamic lift and moment instead of phase lag values for more accurate estimates. This algorithm can be used for one-, two- and three-degree-of-freedom motions. A two-degree-of-freedom forced vibration system was developed and the algorithm was shown to work well for both streamlined and bluff section models. The uniqueness of the second algorithms lies in the fact that it requires testing the model at only two wind speeds for extraction of all four Rational Functions. The Rational Function Coefficients that were extracted for a streamlined section model using the two-DOF Least Squares algorithm were validated in a separate wind tunnel by testing a larger scaled model subject to straight-line, gusty and boundary-layer wind.

  12. Strain Gage Loads Calibration Testing with Airbag Support for the Gulfstream III SubsoniC Research Aircraft Testbed (SCRAT)

    Science.gov (United States)

    Lokos, William; Miller, Eric; Hudson, Larry; Holguin, Andrew; Neufeld, David; Haraguchi, Ronnie

    2015-01-01

    This paper describes the design and conduct of the strain gage load calibration ground test of the SubsoniC Research Aircraft Testbed, Gulfstream III aircraft, and the subsequent data analysis and its results. The goal of this effort was to create and validate multi-gage load equations for shear force, bending moment, and torque for two wing measurement stations. For some of the testing the aircraft was supported by three air bags in order to isolate the wing structure from extraneous load inputs through the main landing gear. Thirty-two strain gage bridges were installed on the left wing. Hydraulic loads were applied to the wing lower surface through a total of 16 load zones. Some dead weight load cases were applied to the upper wing surface using shot bags. Maximum applied loads reached 54,000 pounds.

  13. EEG activity as an objective measure of cognitive load during effortful listening: A study on pediatric subjects with bilateral, asymmetric sensorineural hearing loss.

    Science.gov (United States)

    Marsella, Pasquale; Scorpecci, Alessandro; Cartocci, Giulia; Giannantonio, Sara; Maglione, Anton Giulio; Venuti, Isotta; Brizi, Ambra; Babiloni, Fabio

    2017-08-01

    Deaf subjects with hearing aids or cochlear implants generally find it challenging to understand speech in noisy environments where a great deal of listening effort and cognitive load are invested. In prelingually deaf children, such difficulties may have detrimental consequences on the learning process and, later in life, on academic performance. Despite the importance of such a topic, currently, there is no validated test for the assessment of cognitive load during audiological tasks. Recently, alpha and theta EEG rhythm variations in the parietal and frontal areas, respectively, have been used as indicators of cognitive load in adult subjects. The aim of the present study was to investigate, by means of EEG, the cognitive load of pediatric subjects affected by asymmetric sensorineural hearing loss as they were engaged in a speech-in-noise identification task. Seven children (4F and 3M, age range = 8-16 years) affected by asymmetric sensorineural hearing loss (i.e. profound degree on one side, mild-to-severe degree on the other side) and using a hearing aid only in their better ear, were included in the study. All of them underwent EEG recording during a speech-in-noise identification task: the experimental conditions were quiet, binaural noise, noise to the better hearing ear and noise to the poorer hearing ear. The subjects' Speech Recognition Thresholds (SRT) were also measured in each test condition. The primary outcome measures were: frontal EEG Power Spectral Density (PSD) in the theta band and parietal EEG PSD in the alpha band, as assessed before stimulus (word) onset. No statistically significant differences were noted among frontal theta power levels in the four test conditions. However, parietal alpha power levels were significantly higher in the "binaural noise" and in the "noise to worse hearing ear" conditions than in the "quiet" and "noise to better hearing ear" conditions (p hearing loss with the purpose of studying the cognitive load during

  14. A review of safety, side-effects and subjective reactions to intranasal oxytocin in human research.

    Science.gov (United States)

    MacDonald, Elayne; Dadds, Mark R; Brennan, John L; Williams, Katrina; Levy, Florence; Cauchi, Avril J

    2011-09-01

    Human research investigating the impact of intranasal oxytocin on psychological processes has accelerated over the last two decades. No review of side effects, subjective reactions and safety is available. A systematic review of 38 randomised controlled trials conducted between 1990 and 2010 that investigated the central effects of intranasal oxytocin was undertaken. A systematic search for reports of adverse reactions involving intranasal oxytocin was also completed. Since 1990, research trials have reported on N=1529 (79% male) of which 8% were participants with developmental or mental health difficulties. Dosages ranged from 18 to 40 IU, mainly in single doses but ranged up to 182 administrations. Diverse methods have been used to screen and exclude participants, monitor side effects and subject reactions. Side effects are not different between oxytocin and placebo and participants are unable to accurately report on whether they have received oxytocin and placebo. Three case reports of adverse reactions due to misuse and longer-term use of intranasal oxytocin were reported. The evidence shows that intranasal oxytocin: (1) produces no detectable subjective changes in recipients, (2) produces no reliable side-effects, and (3) is not associated with adverse outcomes when delivered in doses of 18-40 IU for short term use in controlled research settings. Future research directions should include a focus on the dosage and duration of use, and application with younger age groups, vulnerable populations, and with females. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Spatial reliability analysis of a wind turbine blade cross section subjected to multi-axial extreme loading

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov; Bitsche, Robert; Blasques, José Pedro Albergaria Amaral

    2017-01-01

    This paper presents a methodology for structural reliability analysis of wind turbine blades. The study introduces several novel elements by taking into account loading direction using a multiaxial probabilistic load model, considering random material strength, spatial correlation between material...... properties, progressive material failure, and system reliability effects. An example analysis of reliability against material failure is demonstrated for a blade cross section. Based on the study we discuss the implications of using a system reliability approach, the effect of spatial correlation length......, type of material degradation algorithm, and reliability methods on the system failure probability, as well as the main factors that have an influence on the reliability. (C) 2017 Elsevier Ltd. All rights reserved....

  16. Theoretical research and experimental validation of elastic dynamic load spectra on bogie frame of high-speed train

    Science.gov (United States)

    Zhu, Ning; Sun, Shouguang; Li, Qiang; Zou, Hua

    2016-05-01

    When a train runs at high speeds, the external exciting frequencies approach the natural frequencies of bogie critical components, thereby inducing strong elastic vibrations. The present international reliability test evaluation standard and design criteria of bogie frames are all based on the quasi-static deformation hypothesis. Structural fatigue damage generated by structural elastic vibrations has not yet been included. In this paper, theoretical research and experimental validation are done on elastic dynamic load spectra on bogie frame of high-speed train. The construction of the load series that correspond to elastic dynamic deformation modes is studied. The simplified form of the load series is obtained. A theory of simplified dynamic load-time histories is then deduced. Measured data from the Beijing-Shanghai Dedicated Passenger Line are introduced to derive the simplified dynamic load-time histories. The simplified dynamic discrete load spectra of bogie frame are established. Based on the damage consistency criterion and a genetic algorithm, damage consistency calibration of the simplified dynamic load spectra is finally performed. The computed result proves that the simplified load series is reasonable. The calibrated damage that corresponds to the elastic dynamic discrete load spectra can cover the actual damage at the operating conditions. The calibrated damage satisfies the safety requirement of damage consistency criterion for bogie frame. This research is helpful for investigating the standardized load spectra of bogie frame of high-speed train.

  17. Experimental Investigation for Behavior of Reinforced Hybrid Concrete Corbel-Column System Subjected to Un-Symmetrical Vertical Loading

    Directory of Open Access Journals (Sweden)

    Yasir Ali

    2017-05-01

    Full Text Available In this paper, shear and flexural behavior of reinforced hybrid concrete corbel-column system was experimentally investigated. Fourteen hybrid and homogenous concrete corbel-column systemssubjected to un-symmetrical loading were constructed and tested within two test groups (A, B. The experimental program included several variables such as: type of hybrid concrete;high strength concrete(HSC or steel fiber reinforced concrete(SFRC, shear span to depth ratio (a/d, area of hybridization in corbel - column system.Experimental results showed significant effects of concrete hybridization on structural shear and flexural behavior including: ultimate strength, cracking loads, cracking patterns, failure modes, and ductility. Hybridization process ingroup (A included casting the corbel with HSC or SFRC instated of normal strength concrete (NSC. In shear behavior corbels (a/d= 0.37, this process led to increase the shear capacity of corbel by (26%, 38% and shear cracking loads by (20%, 120% respectively. Furthermore, in flexural behavior corbels (a/d= 0.74 shear capacity increased by (19%, 42%, flexural cracking loads increased by (29%, 143% for HSC and SFRC corbels respectively. In group (B hybridization process included increasing the hybrid area of corbel-column system in group (A to represent a distributed region (D-region or decreasing it to represent hybrid corbel. In both cases shear capacity of corbel increased with a range of (10 to 41 % for specimens hybridized monolithically with HSC, while it increased with a range of (19 to 44 % for specimens hybridized monolithically with SFRC; compared with homogenous NSC specimens having same (a/d ratio.

  18. Measurement of Wood Pallet Performance Subjected to Uniform Loading in Racked, Fork Tine, and Floor Stacked Support Conditions

    OpenAIRE

    White, Braden Spencer

    2008-01-01

    Wood pallets are heavily used throughout the United States and the World to transport, store, and protect goods. During a lifecycle, pallets typically experience various stresses from warehouse storage racks, materials handling equipment, and floor stacking situations. The components within the pallet interact to withstand load and impact forces. Every year product damage and human injury/death result from improperly designed pallets, non-reliable packaging systems, and careless materials ...

  19. Teaching Earth Sciences as an interdisciplinary subject: Novel module design involving research literature

    Science.gov (United States)

    Tong, Vincent C. H.

    2010-05-01

    The study of Earth Sciences requires an interdisciplinary approach as it involves understanding scientific knowledge originating from a wide spectrum of research areas. Not only does it include subjects ranging from, for instance, hydrogeology to deep crustal seismology and from climate science to oceanography, but it also has many direct applications in closely related disciplines such as environmental engineering and natural resources management. While research crossing traditional disciplinary boundaries in geosciences is becoming increasingly common, there is only limited integration of interdisciplinary research in the teaching of the subject. Given that the transition from undergraduate education based on subject modules to postgraduate interdisciplinary research is never easy, such integration is a highly desirable pedagogical approach at both undergraduate and postgraduate levels. My presentation is based on a recent teaching project involving novel design of an undergraduate course. The course is implemented in order to address the synergy between research and teaching (Tong, 2009). This project has been shown to be effective and successful in teaching geosciences undergraduates at the University of London. The module consists of studying core geophysical principles and linking them directly to a selection of recently published research papers in a wide range of interdisciplinary applications. Research reviewing and reporting techniques are systematically developed, practised and fully integrated into teaching of the core scientific theories. A fully-aligned assignment with a feedback website invites the students to reflect on the scientific knowledge and the study skills related to research literature they have acquired in the course. This teaching project has been recognized by a teaching award (http://www.clpd.bbk.ac.uk/staff/BETA). In this presentation, I will discuss how undergraduate teaching with a focus on research literature in Earth Sciences can

  20. Experimental investigation and numerical description of the damage evolution in a duplex stainless steel subjected to VHCF-loading

    Energy Technology Data Exchange (ETDEWEB)

    Dönges, B., E-mail: benjamin.doenges@uni-siegen.de [Institut für Werkstofftechnik, Universität Siegen, D-57068 Siegen (Germany); Institut für Mechanik und Regelungstechnik – Mechatronik, Universität Siegen, D-57068 Siegen (Germany); Istomin, K. [Festkörperphysik, Universität Siegen, D-57068 Siegen (Germany); Söker, M. [Fakultät für Ingenieurwissenschaften und Informatik, Hochschule Osnabrück, D-49009 Osnabrück (Germany); Schell, N. [Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung, D-21502 Geesthacht (Germany); Krupp, U. [Fakultät für Ingenieurwissenschaften und Informatik, Hochschule Osnabrück, D-49009 Osnabrück (Germany); Pietsch, U. [Festkörperphysik, Universität Siegen, D-57068 Siegen (Germany); Fritzen, C.-P. [Institut für Mechanik und Regelungstechnik – Mechatronik, Universität Siegen, D-57068 Siegen (Germany); Christ, H.-J. [Institut für Werkstofftechnik, Universität Siegen, D-57068 Siegen (Germany)

    2015-10-14

    The present study documents how the irreversible fraction of cyclic plastic strain, induced by loading amplitudes close to the durability limit, causes fatigue damage such as (i) slip band development, (ii) fatigue crack initiation and (iii) short fatigue crack propagation. The damage evolution of the austenitic–ferritic duplex stainless steel X2CrNiMoN22-5-3 (318 LN) was investigated up to one billion load cycles by means of high resolution electron microscopy (HR-SEM, TEM), focused ion beam (FIB) cutting, confocal laser scanning microscopy (CLSM), in-situ far field microscopy and high-energy (87.1 keV) X-ray diffraction (XRD) experiments. The experimentally identified damage mechanisms were implemented into three-dimensional finite element simulations, which consider crystal plasticity. These simulations enable fatigue life predictions of real microstructures obtained for instance by means of, e.g. automated electron back scatter diffraction (EBSD) analysis. The simulations allow for determining whether microcracks (i) initiate in a microstructure, (ii) arrest in the midst of the first grain, (iii) are permanently, (iv) temporary or (v) not at all blocked by grain or phase boundaries. Moreover, this concept is capable to contribute to the concept of tailored microstructures for improved cyclic-loading behavior.

  1. Stress analysis and damage evolution in individual plies of notched composite laminates subjected to in-plane loads

    Directory of Open Access Journals (Sweden)

    Junshan Hu

    2017-02-01

    Full Text Available This work aims to investigate local stress distribution, damage evolution and failure of notched composite laminates under in-plane loads. An analytic method containing uniformed boundary equations using a complex variable approach is developed to present layer-by-layer stresses around the notch. The uniformed boundary equations established in series together with conformal mapping functions are capable of dealing with irregular boundary issues around the notch and at infinity. Stress results are employed to evaluate the damage initiation and propagation of notched composites by progressive damage analysis (PDA. A user-defined subroutine is developed in the finite element (FE model based on coupling theories for mixed failure criteria and damage mechanics to efficiently investigate damage evolution as well as failure modes. Carbon/epoxy laminates with a stacking sequence of [45°/0°/−60°/90°]s are used to investigate surface strains, in-plane load capacity and microstructure of failure zones to provide analytic and FE methods with strong validation. Good agreement is observed between the analytic method, the FE model and experiments in terms of the stress (strain distributions, damage evaluation and ultimate strength, and the layer-by-layer stress components vary according to a combination effect of fiber orientation and loading type, causing diverse failure modes in individuals.

  2. Performance Evaluation of Waterproofing Membrane Systems Subject to the Concrete Joint Load Behavior of Below-Grade Concrete Structures

    National Research Council Canada - National Science Library

    Jaeyoung Song; Kyuhwan Oh; Byoungil Kim; Sangkeun Oh

    2017-01-01

    .... In this type of environment, they become subject to higher water pressure. The concrete material of the structures is exposed to wet conditions for longer periods of time, which makes the proper adhesion of waterproofing membranes difficult...

  3. If, Why, and When Subjective Well-Being Influences Health, and Future Needed Research.

    Science.gov (United States)

    Diener, Ed; Pressman, Sarah D; Hunter, John; Delgadillo-Chase, Desiree

    2017-07-01

    We review evidence on whether subjective well-being (SWB) can influence health, why it might do so, and what we know about the conditions where this is more or less likely to occur. This review also explores how various methodological approaches inform the study of the connections between subjective well-being and health and longevity outcomes. Our review of this growing literature indicates areas where data are substantial and where much more research is needed. We conclude that SWB can sometimes influence health, and review a number of reasons why it does so. A key open question is when it does and does not do so-in terms of populations likely to be affected, types of SWB that are most influential (including which might be harmful), and types of health and illnesses that are most likely to be affected. We also describe additional types of research that are now much needed in this burgeoning area of interest, for example, cross-cultural studies, animal research, and experimental interventions designed to raise long-term SWB and assess the effects on physical health. This research area is characterised both by potentially extremely important findings, and also by pivotal research issues and questions. © 2017 The Authors. Applied Psychology: Health and Well-Being published by John Wiley & Sons Ltd on behalf of International Association of Applied Psychology.

  4. Recent research activities and future subjects on stable- and radio-isotopes of chlorine in environment

    Energy Technology Data Exchange (ETDEWEB)

    Kushita, Kouhei [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report reviews the recent studies on the stable- and radio-isotopes of chlorine from a viewpoint of environmental science, partly including historic references on this element. First, general properties, occurrence, and utilization of chlorine are described. Secondly, current status and research works on chlorine-compounds, which attract special attention in recent years as environmentally hazardous materials, are reported. Thirdly, research works on stable chlorine isotopes, {sup 35}Cl and {sup 37}Cl, are described with a focus laid on the newly-developed techniques; isotopic ratio mass spectrometry (IRMS) and thermal ionization mass spectrometry (TIMS). Fourthly, recent research works on chlorine radioisotopes, {sup 36}Cl etc., are described, focusing on the development of accelerator mass spectrometry (AMS) and its application to geochemistry and others. Finally, taking account of the above-mentioned recent works on Cl isotopes, possible future research subjects are discussed. (author)

  5. Subject oriented and problem based text materials as a subject of flexible foreign language reading in research projects

    OpenAIRE

    SEROVA TAMARA S.; PIPCHENKO ELENA L.

    2014-01-01

    The article introduces the academic research work of students within the competence based approach, the models of academic problem based research projects taken up as a means to develop flexible foreign language reading skills. The authors reveal selection principles and corpus didactic design of text materials in the form of a macrotext, hypertext, and video course.

  6. Evaluation of P300 components for emotion-loaded visual event-related potential in elderly subjects, including those with dementia.

    Science.gov (United States)

    Asaumi, Yasue; Morita, Kiichiro; Nakashima, Youko; Muraoka, Akemi; Uchimura, Naohisa

    2014-07-01

    In the present study, the P300 component of the emotion-loaded visual event-related potential in response to photographs of babies crying or smiling was measured to evaluate cognitive function in elderly subjects, including those with dementia. The subjects were 48 elderly people who consulted a memory disorder clinic. The visual event-related potential was measured using oddball tasks. Brain waves were recorded from four sites. We analyzed the P300 amplitude and latency. Subjects were divided into three groups (the dementia with Alzheimer's disease group [ADG]; the intermediate group [MG], and the healthy group [HG]) based on the Revised Hasegawa Dementia Scale, Mini-mental State Examination scores and the Clinical Dementia Rating. For all subjects, there was a significant positive correlation between P300 latency and Z-score of voxel-based specific regional analysis for Alzheimer's disease for crying or smiling faces. There was a negative correlation between P300 amplitude and Z-score for the crying face. MG subjects were divided into two groups (high risk: HRMG, low risk: LRMG) based on Z-scores (HRMG ≥ 2.0). The P300 amplitude of ADG was significantly smaller than that of HG, and the P300 latency of ADG was significantly longer than those of other groups for crying or smiling faces. The P300 latency of HRMG was significantly longer than that of LRMG for the smiling face. Furthermore, the P300 latency for the crying face was significantly shorter than that for the smiling face in HG and ADG. These findings suggest that analysis of P300 components of the emotion-loaded visual event-related potential may be a useful neuropsychological index for the diagnosis of Alzheimer's disease and high-risk subjects. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

  7. AP1000 Shield Building Dynamic Response for Different Water Levels of PCCWST Subjected to Seismic Loading considering FSI

    OpenAIRE

    Daogang Lu; Yu Liu; Xiaojia Zeng

    2015-01-01

    Huge water storage tank on the top of many buildings may affect the safety of the structure caused by fluid-structure interaction (FSI) under the earthquake. AP1000 passive containment cooling system water storage tank (PCCWST) placed at the top of shield building is a key component to ensure the safety of nuclear facilities. Under seismic loading, water will impact the wall of PCCWST, which may pose a threat to the integrity of the shield building. In the present study, an FE model of AP1000...

  8. The Investigation Of A 3-Dimensional Human Hip Joint Subjected To Distributed Load By Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mehmet Emin Çetin

    2012-06-01

    Full Text Available In this study, a three dimensionally modeled human hip joint was investigated by using finite element method. During this study, finite element models were prepared for three different prosthesis types namely; Charnley, Muller and Hipokrat and for two different activities as walking and stair climbing motions. Ansys Workbench commercial program was used for finite element analysis by applying distributed load condition. The von- Mises stresses and strains occurred on the cortical and trabecular layers of bone, prosthesis and bone cement which was used to assemble prosthesis into bone's intramedullary canal, were determined at the end of the finite element analysis and compared to each other.

  9. Strain-hardening behavior and microstructure development in polycrystalline as-cast Mg-Zn-Y alloys with LPSO phase subjected to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Shiraishi, Kazuma [Department of Materials Science and Engineering, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan); Mayama, Tsuyoshi, E-mail: mayama@kumamoto-u.ac.jp [Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan); Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Yamasaki, Michiaki [School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, Brisbane, Qld 4072 (Australia); Magnesium Research Center/Department of Materials Science and Engineering, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan); Kawamura, Yoshihito [Magnesium Research Center/Department of Materials Science and Engineering, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan)

    2016-08-30

    The strain-hardening behavior and microstructural development of polycrystalline as-cast Mg-Zn-Y alloys with various volume fractions of the long-period stacking ordered (LPSO) phase subjected to cyclic loading were experimentally evaluated. For all alloys, cyclic loading tests with a constant strain amplitude of 0.5% for up to 100 cycles showed asymmetric cyclic hardening behavior. That is, the absolute value of the compressive peak stress significantly increased during cyclic loading while the tensile peak stress slightly decreased. With increasing volume fraction of the LPSO phase, the stress amplitude significantly increased. Cyclic loading tests after compressive preloading up to 200 or 250 MPa resulted in a significant increase in the stress amplitude, while a number of kink bands developed during preloading. For the cyclic hardening behavior, the contribution of the increase in kinematic hardening was significant in the alloys with a higher volume fraction of the LPSO phase. Transmission electron microscopy observation of the cyclically deformed Mg{sub 85}Zn{sub 6}Y{sub 9} alloy indicated the formation of a deformation-induced band, where the crystal structure was transformed from 18R-LPSO to hcp-Mg with the exclusion of solute elements.

  10. Ball's motion, sliding friction, and internal load distribution in a high-speed ball bearing subjected to a combined radial, thrust, and moment load, applied to the inner ring's center of mass: Numerical procedure

    Science.gov (United States)

    César Ricci, Mário

    2015-10-01

    In a companion paper of this was introduced a set of non-linear algebraic equations for ball's motion, sliding friction and internal loading distribution computation in a high-speed, single-row, angular-contact ball bearing, subjected to a known combined radial, thrust and moment load, which must be applied to the inner ring's center of mass. It was shown there that it is required the iterative solution of 9Z + 3 simultaneous non-linear equations - where Z is the number of balls - to yield exact solution for contact angles, ball attitude angles, rolling radii, normal contact deformations and axial, radial, and angular deflections of the inner ring with respect the outer ring. The Newton-Rhapson method is to be used to solve the problem. This paper deals with the numerical procedure description. The numerical results derived from the described procedure shall be published later.

  11. Effect Sizes as Result Interpretation Aids in Single-Subject Experimental Research: Description and Application of Four Nonoverlap Methods

    Science.gov (United States)

    Rakap, Salih

    2015-01-01

    Single-subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single-subject experimental research designs are…

  12. Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis.

    Science.gov (United States)

    Svahn, Sara L; Ulleryd, Marcus A; Grahnemo, Louise; Ståhlman, Marcus; Borén, Jan; Nilsson, Staffan; Jansson, John-Olov; Johansson, Maria E

    2016-04-01

    Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics,S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. GLP-1 and peptide YY secretory response after fat load is impaired by insulin resistance, impaired fasting glucose and type 2 diabetes in morbidly obese subjects.

    Science.gov (United States)

    Fernández-García, José C; Murri, Mora; Coin-Aragüez, Leticia; Alcaide, Juan; El Bekay, Rajaa; Tinahones, Francisco J

    2014-05-01

    Both glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) are gut hormones involved in energy homoeostasis. Obesity, insulin resistance and hyperglycaemia are significant confounders when GLP-1 and PYY secretion is assessed. Thus, we evaluated GLP-1 and PYY response after fat load in morbidly obese patients with different degrees of insulin resistance and glycemic status. We studied 40 morbidly obese subjects (mean age, 40·6 ± 1·3 years; mean BMI, 53·1 ± 1·2 kg/m(2) ) divided into groups according to their glycemic status: normal fasting glucose (NFG) group, impaired fasting glucose (IFG) group and type 2 diabetes mellitus (T2D) group. NFG patients were additionally subclassified, according to the homoeostasis model assessment of insulin resistance (HOMAIR ), into a low insulin-resistance (LIR) group (HOMAIR response to fat load. The implications of this attenuated enteroendocrine response should be elucidated by further studies. © 2013 John Wiley & Sons Ltd.

  14. [The request for consent in clinical research: a randomized study in healthy subjects].

    Science.gov (United States)

    Perrone, F; De Placido, S; Giusti, C; Gallo, C

    1995-09-01

    To compare two strategies of consent requirement (classical informed consent and randomised consent according to Zelen), the Clinical Data Elaboration Centre of South Italy, within the special project Clinical Application of Oncological Research of the National Research Council of Italy (CNR-ACRO) invited healthy people visiting the 7th edition of the scientific exhibition "Futuro Remoto" to simulate of being ill and receiving the offer of entering a clinical trial. Within informed consent strategy patients are asked to agree to the randomisation process, while, in the randomised consent, randomised treatment assignment is performed before consent requirement and patients should agree directly to the assigned therapy. Major aims of the study were (a) to compare the strategies in terms of refusal rate to a hypothetical clinical trial, and (b) to estimate whether severity of prognosis affected subjects' decision. 3,217 visiting people participated to the simulation; they were prevalently young, males and with a high level of school education. The study was performed in two different scenarios. In the first one, with one choice option, subject refusing consent could receive standard therapy only; refusal rate was 16% after informed consent and 13.4% after randomised consent (for experimental therapy). In the other scenario, with two choice options, subjects refusing consent could choose the preferred therapy; refusal rate was 20.6% after informed consent, 48.1% after randomised consent (for standard therapy) and 13.4% after randomised consent (for experimental therapy).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Research on the Performance of Electric Vehicles in Peak Load Shifting

    Directory of Open Access Journals (Sweden)

    Qingshan Xu

    2014-01-01

    Full Text Available Electric vehicles (EVs are developing remarkably fast these years which makes the technology of vehicle-to-grid (V2G easier to implement. Peak load shifting (PLS is an important part of V2G service. A model of EVs’ capacity in V2G service is proposed for the research on PLS in this paper. The capacity is valued in accordance with three types of situations. Based on the model, three different scenarios are suggested in order to evaluate the capacity with MATLAB. The evaluation results indicate that EVs can provide potential energy to participate in PLS. Then, the principle of PLS with EVs is researched through the analysis of the relationship between their power and capacity. The performance of EVs in PLS is also simulated. The comparison of two simulation results shows that EVs can fulfill the request of PLS without intensely lowering their capacity level.

  16. The effect of shoe design and lateral wedges on knee load and neuromuscular control in healthy subjects during walking

    DEFF Research Database (Denmark)

    Mølgaard, Carsten; Kersting, Uwe G.

    2014-01-01

    design/type on the effectiveness of lateral wedging has not been investigated so far. The Purpose of the present study was to explore alterations in knee loading due to lateral foot wedges in three different shoes. Methods: Thirteen healthy participants with no history of knee pain were tested using...... wedging is effective regardless of shoe design. Differences between the three neutral walking conditions underline the importance of footwear choice in individuals. It is safe to apply lateral wedges without jeopardising muscular control during walking regardless of shoe type. Possible effects of altering...... three-dimensional gait analysis. Barefoot walking, walking in a running shoe, an Oxford-type leather shoe, and a rocker shoe were analysed. The shoes were tested both with and without a 10-degree full-length laterally wedged insole. Results: There were significant shoe wedge interactions on the first...

  17. Comparison of Fracture Characteristics of Open-Hole-Notch Carbon-Fiber-Reinforced Composites Subjected to Tensile and Compressive Loadings

    Science.gov (United States)

    Saeed, M.-U.; Chen, Z. F.; Chen, Z. H.; Li, B. B.

    2017-01-01

    Open-hole tension (OHT) and open-hole compression (OHC) tests were carried out on hot-pressed carbon-fiberreinforced composite samples with a singular open hole. The fracture surfaces of the OHT- and OHC-tested specimens were examined by using scanning electron microscopy (SEM). SEM micrographs showed significant features on the surface of carbon fiber, matrix, and especially in the fiber/matrix interface. Interpretation of these micrographs revealed the possible failure mechanism of composite samples with an open hole under tensile and compressive loadings. Furthermore, a comparative study of these micrographs also pointed to certain specific differences between the fracture characteristics of open-hole composite samples failed under tension and compression. This information is useful in the post-failure analysis of a composite structure.

  18. Assessment of the Dynamic Behaviour of Saturated Soil Subjected to Cyclic Loading from Offshore Monopile Wind Turbine Foundations

    DEFF Research Database (Denmark)

    Damgaard, Mads; Bayat, Mehdi; Andersen, Lars Vabbersgaard

    2014-01-01

    The fatigue life of offshore wind turbines strongly depends on the dynamic behaviour of the structures including the underlying soil. To diminish dynamic amplification and avoid resonance, the eigenfrequency related to the lowest eigenmode of the wind turbine should not coalesce with excitation...... frequencies related to strong wind, wave and ice loading. Typically, lateral response of monopile foundations is analysed using a beam on a nonlinear Winkler foundation model with soil-pile interaction recommended by the design regulations. However, as it will be shown in this paper, the guideline approaches...... consequently underestimate the eigenfrequency compared to full-scale measurements. This discrepancy leads the authors to investigate the influence of pore water pressure by utilising a numerical approach and consider the soil medium as a two-phase system consisting of a solid skeleton and a single pore fluid...

  19. Single-subject research designs in pediatric rehabilitation: a valuable step towards knowledge translation.

    Science.gov (United States)

    Romeiser-Logan, Lynne; Slaughter, Rebecca; Hickman, Robbin

    2017-06-01

    Knowledge translation may be particularly challenging in pediatric rehabilitation, where study findings are often ambiguous owing to low statistical power or inconsistent responses to intervention. Disconnection between research protocols and clinical practicality, as well as variability of responsiveness in heterogeneous pediatric populations, may further impede integration of research findings into everyday practice. Use of single-subject research designs (SSRDs) may bridge the gap between research and practice, with robust design options that better identify and preserve patterns of responsiveness to specific interventions and offer protocols that are more readily implemented in practice settings than can be done in traditional randomized controlled trials. This review defines SSRD, provides examples of research questions that can be answered using SSRD, details the experimental designs that can be used and the level of evidence of each design, and describes statistical analysis approaches and clinical application. This analysis will aid researchers, reviewers, clinicians, and others in better understanding SSRD methodology and its application in everyday practice. © 2017 Mac Keith Press.

  20. Research on automatic loading & unloading technology for vertical hot ring rolling process

    OpenAIRE

    Xiaokai Wang; Dehui Wang; Xuesong Mei; Lin Hua; Yutong Dai; Jian Wu

    2015-01-01

    The automatic loading & unloading technology is the key to the automatic ring production line. In this paper, the automatic vertical hot ring rolling (VHRR) process is taken as the target, the method of the loading & unloading for VHRR is proposed, and the mechanical structure of loading & unloading system is designed, The virtual prototype model of VHRR mill and loading & unloading mechanism is established, and the coordinated control method of VHRR mill and loading & unloading auxiliaries i...

  1. Research on virtual network load balancing based on OpenFlow

    Science.gov (United States)

    Peng, Rong; Ding, Lei

    2017-08-01

    The Network based on OpenFlow technology separate the control module and data forwarding module. Global deployment of load balancing strategy through network view of control plane is fast and of high efficiency. This paper proposes a Weighted Round-Robin Scheduling algorithm for virtual network and a load balancing plan for server load based on OpenFlow. Load of service nodes and load balancing tasks distribution algorithm will be taken into account.

  2. Research of the launch vehicle design made of composite materials under the aerodynamic, thermal and acoustic loadings

    Directory of Open Access Journals (Sweden)

    Davydovich Denis

    2017-01-01

    Full Text Available The experimental research of the carbon composite material sample of payload fairing half structural element was carried out under different types of loading. Mathematical and physical modeling of the sample loading using aerodynamic flow was conducted. Heat loading was researched by the method of a thermal analysis during which typical heat dots corresponding to the changes in the sample structure were determined. Ultrasonic influence on the sample characteristics was considered. As a result, the value of heat leak to the structure surface while moving in the atmospheric phase of the descent was determined.

  3. X-ray and finite element analysis of deformation response of closed-cell metal foam subjected to compressive loading

    Czech Academy of Sciences Publication Activity Database

    Jiroušek, Ondřej; Doktor, Tomáš; Kytýř, Daniel; Zlámal, Petr; Fíla, Tomáš; Koudelka_ml., Petr; Jandejsek, Ivan; Vavřík, Daniel

    2013-01-01

    Roč. 8, č. 2 (2013), s. 2012-2016 ISSN 1748-0221 R&D Projects: GA ČR GAP105/12/0824 Institutional support: RVO:68378297 Keywords : X-ray radiography and digital radiography * computerized tomography and computed radiography * pixelated detectors and associated VLSI electronics Subject RIV: JG - Metallurgy Impact factor: 1.526, year: 2013 http://iopscience.iop.org/1748-0221/8/02/C02012

  4. Older adults' attitudes toward enrollment of non-competent subjects participating in Alzheimer's research.

    Science.gov (United States)

    Karlawish, Jason; Rubright, Jonathan; Casarett, David; Cary, Mark; Ten Have, Thomas; Sankar, Pamela

    2009-02-01

    Research that seeks to enroll noncompetent patients with Alzheimer's disease without presenting any potential benefit to participants is the source of substantial ethical controversy. The authors used hypothetical Alzheimer's disease studies that included either a blood draw or a blood draw and lumbar puncture to explore older persons' attitudes on this question. Face-to-face interviews were conducted with 538 persons age 65 and older. Questions explored participants' understanding of research concepts, their views on enrolling persons with Alzheimer's disease in research, and their preferences regarding having a proxy decision maker, granting advance consent, and granting their proxy leeway to override the participant's decision. Additional questions assessed altruism, trust, value for research, and perceptions of Alzheimer's disease. The majority (83%) were willing to grant advance consent to a blood draw study, and nearly half (48%) to a blood draw plus lumbar puncture study. Most (96%) were willing to identify a proxy for research decision making, and most were willing to grant their proxy leeway over their advance consent: 81% for the blood draw study and 70% for the blood draw plus lumbar puncture study. Combining the preferences for advance consent and leeway, the proportion who would permit being enrolled in the blood draw and lumbar puncture studies, respectively, were 92% and 75%. Multivariate models showed that willingness to be enrolled in research was most strongly associated with a favorable attitude toward biomedical research. Older adults generally support enrolling noncompetent persons with Alzheimer's disease into research that does not present a benefit to subjects. Willingness to grant their proxy leeway over advance consent and a favorable attitude about biomedical research substantially explain this willingness.

  5. Some recent developments in the international guidelines on the ethics of research involving human subjects.

    Science.gov (United States)

    Levine, R J

    2000-11-01

    We are in a period of reconsideration and revision of international ethical guidelines for the conduct of biomedical research involving human subjects. The proximate cause of much of this activity is the recent controversy over the ethics of the use of a placebo control in the clinical trials of the short-duration regimen of zidovudine for prevention of perinatal transmission of HIV infection, trials that were carried out in several so-called technologically developing countries. Critics of these trials claimed that they were in violation of Article II.3 of the Declaration of Helsinki, which states: "In any medical study, every patient--including those of a control group, if any--should be assured of the best proven diagnostic and therapeutic method. This does not exclude the use of inert placebo in studies where no proven diagnostic or therapeutic method exists." The critics claimed that since the "best proven ... method" is the 076 regimen, this is what must be provided to members of the control groups. Failure to do so, they asserted, was a serious breach of ethics. In response to this allegation, several major international and national agencies convened multidisciplinary groups to consider the ethics of multinational clinical research. The first thing they realized was that Article II.3 was in error in that it did not reflect contemporary ethical thinking. Moreover, it was routinely violated in research conducted in developed as well as in developing countries. What replaces this standard? The 1993 CIOMS International Ethical Guidelines for Biomedical Research Involving Human Subjects include several criteria for justification of research carried out in developing countries. Most importantly, the research must be responsive to the health needs and priorities of the host country. They also require that any therapeutic products developed in such research must be made "reasonably available" to residents of the host country. A new standard is emerging for

  6. AP1000 Shield Building Dynamic Response for Different Water Levels of PCCWST Subjected to Seismic Loading considering FSI

    Directory of Open Access Journals (Sweden)

    Daogang Lu

    2015-01-01

    Full Text Available Huge water storage tank on the top of many buildings may affect the safety of the structure caused by fluid-structure interaction (FSI under the earthquake. AP1000 passive containment cooling system water storage tank (PCCWST placed at the top of shield building is a key component to ensure the safety of nuclear facilities. Under seismic loading, water will impact the wall of PCCWST, which may pose a threat to the integrity of the shield building. In the present study, an FE model of AP1000 shield building is built for the modal and transient seismic analysis considering the FSI. Six different water levels in PCCWST were discussed by comparing the modal frequency, seismic acceleration response, and von Mises stress distribution. The results show the maximum von Mises stress emerges at the joint of shield building roof and water around the air inlet. However, the maximum von Mises stress is below the yield strength of reinforced concrete. The results may provide a reference for design of the AP1000 and CAP1400 in the future.

  7. Microstructure Evolution and Protrusion of Electroplated Cu-Filled Through-Silicon Vias Subjected to Thermal Cyclic Loading

    Science.gov (United States)

    Chen, Si; An, Tong; Qin, Fei; Chen, Pei

    2017-10-01

    Through-silicon vias (TSVs) have become an important technology for three-dimensional integrated circuit (3D IC) packaging. Protrusion of electroplated Cu-filled vias is a critical reliability issue for TSV technology. In this work, thermal cycling tests were carried out to identify how the microstructure affects protrusion during thermal cycling. Cu protrusion occurs when the loading temperature is higher than 149°C. During the first five thermal cycles, the grain size of Cu plays a dominant role in the protrusion behavior. Larger Cu grain size before thermal cycling results in greater Cu protrusion. With increasing thermal cycle number, the effect of the Cu grain size reduces and the microstrain begins to dominate the Cu protrusion behavior. Higher magnitude of microstrain within Cu results in greater protrusion increment during subsequent thermal cycles. When the thermal cycle number reaches 25, the protrusion rate of Cu slows down due to strain hardening. After 30 thermal cycles, the Cu protrusion stabilizes within the range of 1.92 μm to 2.09 μm.

  8. Pupil diameter as predictor of cognitive load: A novel tool for geoscience education research

    Science.gov (United States)

    Mitra, R.; McNeal, K.

    2015-12-01

    Pupils can truly serve as windows to the mind. Since the early part of the last decade, pupillometry, the study of pupils in response to cognitive tasks, have gained traction in psychophysiological studies. Muscles of the iris work in tandem with the autonomic nervous system in response to light condition to either dilate or contract the pupil, usually between 2 to 7 mm. Along with this response to light conditions, the pupils also contract or dilate in response to emotional or mental response. Therefore, for a cognitive task, if the ambient brightness is controlled, pupil dilation reflects the cognitive load associated with the task. Simple tasks such as counting, memorizing, multiplying and visual searching have been found to have pupillometry profiles reflective of the cognitive load involved with such tasks. In this study, we investigate whether pupil diameter can be used for education research where tasks can be more complex. In particular, we look at two specific types of tasks common in geoscience and several other STEM fields: graph reading and spatial problem solving.

  9. RESEARCH OF IMPACT OF THE LOADING ON ENDURANCE OF THE FREIGHT LOCOMOTIVE ENGINES

    Directory of Open Access Journals (Sweden)

    Sergejus LEBEDEVAS

    2015-12-01

    Full Text Available The publication reflects the research results of the rationalization of the rolling stock use of JSC LG Lithuanian railways to increase the reliability indicators of the freight diesel locomotive exploitation reliability. The comparative evaluation of the exploited freight diesel locomotive work duration, according to the technical documentation, by using comparative test results and indirect diesel reliability criteria approved in practice. An algorithm of work duration forecasting methodology has been created, as well as a programme complex of mathematic modelling. The differences of the results indicated in the experiment and modelled by computer do not exceed 5 ÷ 7%. The proposed and described methodology of the diesel locomotive exploitation load cycle dynamic indicator reduction, by the use of which the following is achieved: increase of the diesel work duration by 7÷10%, reduction of fuel consumption up to 10%, reduction of the load cycle dynamic indicators (increasing the fatigue stress of parts and units of the diesel by 15÷20%.

  10. RESEARCHING CITY AND SUBJECTIVITY: BODIES AND WANDERINGS OF A FLÂNEUR- CARTOGRAPHER

    Directory of Open Access Journals (Sweden)

    Manuela Linck de Romero

    2016-11-01

    Full Text Available In light of the cartographic method of research proposed by Gilles Deleuze and Félix Guattari (2011, we present reflections on the study on subjectivity and the contemporary city with an approach to its process and production dimensions. The cartographer’s body is crucial for the methodology and is created along the research process in order to allow for the existence of universes of reference (Rolnik, 1993 of modes of existence in urban life. We then develop relationships between the cartographer’s practice and that of the flâneur as examples of urban wandering (Jacques, 2012 that problematize the possibilities of body experiences in the urban space as a resistance to the contemporary spectacularization of the city. For such, we use concepts-tools from the field of schizoanalysis and those of the authors mentioned in this abstract, developing the idea that urban experiences, in some ways, can prove to be a source of production and knowledge of subjectivity, the city, the body and the relationships between them.

  11. Subject-specific finite element modelling of the human foot complex during walking: sensitivity analysis of material properties, boundary and loading conditions.

    Science.gov (United States)

    Akrami, Mohammad; Qian, Zhihui; Zou, Zhemin; Howard, David; Nester, Chris J; Ren, Lei

    2017-11-14

    The objective of this study was to develop and validate a subject-specific framework for modelling the human foot. This was achieved by integrating medical image-based finite element modelling, individualised multi-body musculoskeletal modelling and 3D gait measurements. A 3D ankle-foot finite element model comprising all major foot structures was constructed based on MRI of one individual. A multi-body musculoskeletal model and 3D gait measurements for the same subject were used to define loading and boundary conditions. Sensitivity analyses were used to investigate the effects of key modelling parameters on model predictions. Prediction errors of average and peak plantar pressures were below 10% in all ten plantar regions at five key gait events with only one exception (lateral heel, in early stance, error of 14.44%). The sensitivity analyses results suggest that predictions of peak plantar pressures are moderately sensitive to material properties, ground reaction forces and muscle forces, and significantly sensitive to foot orientation. The maximum region-specific percentage change ratios (peak stress percentage change over parameter percentage change) were 1.935-2.258 for ground reaction forces, 1.528-2.727 for plantar flexor muscles and 4.84-11.37 for foot orientations. This strongly suggests that loading and boundary conditions need to be very carefully defined based on personalised measurement data.

  12. Investigation of thermomechanical couplings, strain localization and shape memory properties in a shape memory polymer subjected to loading at various strain rates

    Science.gov (United States)

    Pieczyska, E. A.; Staszczak, M.; Maj, M.; Kowalczyk-Gajewska, K.; Golasiński, K.; Cristea, M.; Tobushi, H.; Hayashi, S.

    2016-08-01

    This paper presents experimental and modeling results of the effects of thermomechanical couplings occurring in a polyurethane shape memory polymer (SMP) subjected to tension at various strain rates within large strains. The SMP mechanical curves, recorded using a testing machine, and the related temperature changes, measured in a contactless manner using an IR camera, were used to investigate the polymer deformation process at various loading stages. The effects of thermomechanical couplings allowed the determination of the material yield point in the initial loading stage, the investigation of nucleation and development of the strain localization at larger strains and the estimation of the effects of thermoelastic behavior during the unloading process. The obtained stress-strain and thermal characteristics, the results of the dynamic mechanical analysis and estimated values of the shape fixity and shape recovery parameters confirmed that the shape memory polymer (T g = 45 °C) is characterized by good mechanical and shape memory properties, as well as high sensitivity to the strain rate. The mechanical response of the SMP subjected to tension was simulated using the finite element method and applying the large strain, two-phase model. Strain localization observed in the experiment was well reproduced in simulations and the temperature spots were correlated with the accumulated viscoplastic deformation of the SMP glassy phase.

  13. NASA's Universe of Learning: The Integral Role of Research Astronomers and Other Subject Matter Experts

    Science.gov (United States)

    Lee, Janice; Universe of Learning Team

    2018-01-01

    Astronomy seeks to understand the workings of the Universe on its largest scales, and to answer fundamental questions about the story of our origins. The science of astronomy thus naturally lends itself to informal education and public outreach activities, as it broadly captures the human imagination. There are at least three overall goals for investment of resources in Astronomy E/PO: to interest students in pursuing STEM education and careers; to develop Astronomy as context for teaching more basic physical and computer science in service of US National Education Goals; to help motivate continued public support of federally funded Astronomy research and technology development. Providing a full spectrum of opportunities for the public to learn about recent Astronomy discoveries is key to achieving these societal goals. Thus, the E/PO professional community must have an understanding of recent scientific/technological results, and engage with the researchers who are creating new knowledge to explicate that knowledge to the public. It stands to reason that researchers (or “subject matter experts, SMEs”) must be involved in and remain connected to the E/PO endeavor. In this talk, I will describe how research astronomers and other SMEs play an integral role in a full range of informal education programming developed by the NASA Universe of Learning collaboration, and opportunities to get involved.

  14. Metal loading in Soda Butte Creek upstream of Yellowstone National Park, Montana and Wyoming; a retrospective analysis of previous research; and quantification of metal loading, August 1999

    Science.gov (United States)

    Boughton, G.K.

    2001-01-01

    Acid drainage from historic mining activities has affected the water quality and aquatic biota of Soda Butte Creek upstream of Yellowstone National Park. Numerous investigations focusing on metals contamination have been conducted in the Soda Butte Creek basin, but interpretations of how metals contamination is currently impacting Soda Butte Creek differ greatly. A retrospective analysis of previous research on metal loading in Soda Butte Creek was completed to provide summaries of studies pertinent to metal loading in Soda Butte Creek and to identify data gaps warranting further investigation. Identification and quantification of the sources of metal loading to Soda Butte Creek was recognized as a significant data gap. The McLaren Mine tailings impoundment and mill site has long been identified as a source of metals but its contribution relative to the total metal load entering Yellowstone National Park was unknown. A tracer-injection and synoptic-sampling study was designed to determine metal loads upstream of Yellowstone National Park.A tracer-injection and synoptic-sampling study was conducted on an 8,511-meter reach of Soda Butte Creek from upstream of the McLaren Mine tailings impoundment and mill site downstream to the Yellowstone National Park boundary in August 1999. Synoptic-sampling sites were selected to divide the creek into discrete segments. A lithium bromide tracer was injected continuously into Soda Butte Creek for 24.5 hours. Downstream dilution of the tracer and current-meter measurements were used to calculate the stream discharge. Stream discharge values, combined with constituent concentrations obtained by synoptic sampling, were used to quantify constituent loading in each segment of Soda Butte Creek.Loads were calculated for dissolved calcium, silica, and sulfate, as well as for dissolved and total-recoverable iron, aluminum, and manganese. Loads were not calculated for cadmium, copper, lead, and zinc because these elements were infrequently

  15. Experimental and analytical program to determine strains in 737 LAP splice joints subjected to normal fuselage pressurization loads

    Energy Technology Data Exchange (ETDEWEB)

    Roach, D.P. [Sandia National Labs., Albuquerque, NM (United States); Jeong, D.Y. [Department of Transportation, Cambridge, MA (United States). John A. Volpe National Transportation Systems Center

    1996-02-01

    The Federal Aviation Administration Technical Center (FAATC) has initiated several research projects to assess the structural integrity of the aging commercial aircraft fleet. One area of research involves the understanding of a phenomenon known as ``Widespread Fatigue Damage`` or WFD, which refers to a type of multiple element cracking that degrades the damage tolerance capability of an aircraft structure. Research on WFD has been performed both experimentally and analytically including finite element modeling of fuselage lap splice joints by the Volpe Center. Fuselage pressurization tests have also been conducted at the FAA`s Airworthiness Assurance NDI Validation Center (AANC) to obtain strain gage data from select locations on the FAA/AANC 737 Transport Aircraft Test Bed. One-hundred strain channels were used to monitor five different lap splice bays including the fuselage skin and substructure elements. These test results have been used to evaluate the accuracy of the analytical models and to support general aircraft analysis efforts. This paper documents the strain fields measured during the AANC tests and successfully correlates the results with analytical predictions.

  16. Research on the Operation Mode of Intelligent-town Energy Internet Based on Source-Load Interaction

    Science.gov (United States)

    Li, Hao; Li, Wen; Miao, Bo; Li, Bin; Liu, Chang; Lv, Zhipeng

    2018-01-01

    On the background of the rise of intelligence and the increasing deepening of “Internet +”application, the energy internet has become the focus of the energy research field. This paper, based on the fundamental understanding on the energy internet of the intelligent town, discusses the mode of energy supply in the source-load interactive region, and gives an in-depth study on the output characteristics of the energy supply side and the load characteristics of the demand side, so as to derive the law of energy-load interaction of the intelligent-town energy internet.

  17. A comparison of EBSD based strain indicators for the study of Fe-3Si steel subjected to cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Schayes, Claire [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Valeo Engine Electrical Systems, 2 Rue André Boulle, 94046 Créteil (France); Bouquerel, Jérémie, E-mail: jeremie.bouquerel@univ-lille1.fr [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Vogt, Jean-Bernard [Université Lille 1 sciences et technologies, UMET – UMR CNRS 8207/ENSCL/Université de Lille, team Métallurgie Physique et Génie des Matériaux, Bâtiment C6, 59655 Villeneuve d' Ascq (France); Palleschi, Frédéric [Valeo Engine Electrical Systems, 2 Rue André Boulle, 94046 Créteil (France); Zaefferer, Stefan [Max-Planck-Institut für Eisenforschung, Abteilung Mikrostrukturphysik und Umformtechnik, Max-Planck-Strasse 1, 40237 Düsseldorf (Germany)

    2016-05-15

    The current work aims at proposing an EBSD-based indicator for fatigue damage of a Fe-3Si steel. At the same time direct observation of dislocation structures is provided by electron channelling contrast imaging (ECCI). The investigation consisted in processing the EBSD data from patterns collected on specimen subjected to low cycle fatigue. It revealed two different regimes depending on the applied total strain variation which is explained by the identification of the dislocations structures and their evolution. At low strain variation, strain accommodation occurs by planar glide of dislocations uniformly distributed throughout the grains. No misorientation evolution is observed. At higher strain variation, the vein-channel structure is observed within the grain and the wall-channel structure in the vicinity of grain boundaries. The misorientation between these two dislocation structures is evaluated at about 0.7° which is detected by the EBSD analyses and explains the increase of the different misorientation based criteria. The EBSD study enables also the prediction of crack initiation mode. Finally, this study points out the limits of the EBSD technique as no misorientation evolution is detected at small strain variation. Indeed, the lattice distortion is too weak to be detected by conventional EBSD. - Highlights: • Microstructure investigation of the fatigue behaviour of an iron-silicon steel • Use of cECCI to investigate the fatigue dislocations structures • Characterisation of local plastic accommodation through EBSD misorientation criteria.

  18. Effects of three-day bed rest on metabolic, hormonal and circulatory responses to an oral glucose load in endurance or strength trained athletes and untrained subjects.

    Science.gov (United States)

    Smorawiński, J; Kaciuba-Uściłko, H; Nazar, K; Kubala, P; Kamińska, E; Ziemba, A W; Adrian, J; Greenleaf, J E

    2000-06-01

    The study was designed to find out (1) whether the effect of 3-day bed rest on blood glucose (BG) and plasma insulin (IRI) responses to glucose ingestion depends on preceding physical activity and (2) whether plasma adrenaline (A), noradrenaline (NA) and cardiovascular changes following a glucose load are modified by bed rest. Eleven sedentary students (22.5+/-0.3 yrs), 8 long distance runners (18.6+/-0.3 yrs) and 10 strength trained athletes (21.2+/-2.1 yrs) were examined before and after bed rest. Plasma IRI, BG, NA, A, heart rate (HR), and blood pressure (BP) were measured during 2 hrs following glucose (75 g) ingestion. The responses of BG and IRI to glucose load were calculated as incremental areas under the curves (auc). Both in athletes and untrained subjects bed rest markedly increased IRIauc, while BGauc was elevated only in sedentary subjects (p<0.05). The greatest increases in IRIauc and IRI/BG ratios were found in the endurance athletes. The data from all subjects (n = 29) revealed that the initial plasma NA and glucose-induced increases in NA and A were lowered after bed rest (p < 0.01). These effects were most pronounced in the endurance athletes. Bed rest did not influence HR or BP in any group. It is concluded that (1) the athletes have more adequate compensation for the bed-rest-induced decrement in insulin sensitivity than sedentary men; (2) three-day bed rest diminishes basal sympathetic activity and attenuates sympathoadrenal response to oral glucose; (3) endurance athletes have greater sympathetic inhibition than strength athletes or sedentary men.

  19. Current research on shear buckling and thermal loads with PASCO: Panel Analysis and Sizing Code

    Science.gov (United States)

    Stroud, W. J.; Greene, W. H.; Anderson, M. S.

    1981-01-01

    The PASCO computer program to obtain the detailed dimensions of optimum stiffened composite structural panels is described. Design requirements in terms of inequality constraints can be placed on buckling loads or vibration frequencies, lamina stresses and strains, and overall panel stiffness for each of many load conditions. General panel cross sections can be treated. An analysis procedure involving a smeared orthotropic solution was investigated. The conservatism in the VIPASA solution and the danger in a smeared orthotropic solution is explored. PASCO's capability to design for thermal loadings is also described. It is emphasized that design studies illustrate the importance of the multiple load condition capability when thermal loads are present.

  20. How children can be respected as 'ends' yet still be used as subjects in non-therapeutic research.

    Science.gov (United States)

    Redmon, R B

    1986-01-01

    The question of whether or not children may be used as subjects in non-therapeutic research projects has generated a great deal of debate and received answers varying from 'no, never' to 'yes, if societal interests are served'. It has been claimed that a Kantian, deontological ethics would necessarily rule out such research, since valid consent would be impossible. The present paper gives a deontological argument for allowing children to be subjects in certain types of research. PMID:3735361

  1. Psychometric evaluation and establishing norms of Croatian SF-36 health survey: framework for subjective health research.

    Science.gov (United States)

    Maslić Sersić, Darja; Vuletić, Gorka

    2006-02-01

    To provide population norms and evaluate metric characteristics of the Croatian version of SF-36 Health Survey, an internationally used instrument for assessing subjective health. The questionnaire was administered to a representative sample of Croatian adult population (n=9070). Three standard techniques were used in data analysis: reliability tests, descriptive statistics, and factor analysis. The population norms were presented in two standard forms--the SF-36 Health Profile and percentile values for different age groups of men and women. The Croatian version of the SF-36 had generally acceptable metric characteristics including its construct validity. The internal consistency of the SF-36 scales ranged from 0.78 to 0.94. Pearson bivariate correlations showed moderate associations between SF-36 scales, and factor analysis provided one latent dimension underlying all SF-36 scales which explained 63.3% of the score variance. Less favorable results were obtained concerning its discriminative validity. All SF-36 scales showed negative asymmetry of score distributions, and some had high floor and ceiling effects--skewness estimations ranged from -0.12 to -0.91, with the highest floor effect of 30% and ceiling effect of 63%. Presented population norms for the Croatian version of SF-36 Health Survey showed that SF-36 may be used as a valid and reliable instrument in research in subjective health of Croatian population.

  2. Documentation of ethical conduct of human subject research published in Saudi medical journals.

    Science.gov (United States)

    Al-Gaai, E A; Hammami, M M; Al Eidan, M

    2012-07-01

    We evaluated the documentation of ethical conduct (obtaining institutional review board approval and consent and following ethical guidelines) of human subject research studies published in Saudi Arabian medical journals between 1979 and 2007. Studies were classified as retrospective, prospective noninterventional, interventional or survey/interview. Of 1838 studies published in 286 journal issues of 11 Saudi Arabian medical journals, only 0.9% documented the ethical guidelines followed, with a significantly higher rate for studies published after year 2000 (1.7%). Of 821 studies requiring institutional review board approval, 8.6% documented obtaining the approval and informed consent, with a significantly higher rate for interventional studies (19.4%), post-year 2000 studies (19.7%) and studies performed outside Saudi Arabia (15.9%). The low documentation rate suggests editor's lack of rigor and/or investigators' ignorance of guidelines. The higher documentation rate after year 2000 suggests an ongoing improvement.

  3. Strain Rate Dependent Deformation of a Polymer Matrix Composite with Different Microstructures Subjected to Off-Axis Loading

    Directory of Open Access Journals (Sweden)

    Xiaojun Zhu

    2014-01-01

    Full Text Available This paper aims to investigate the comprehensive influence of three microstructure parameters (fiber cross-section shape, fiber volume fraction, and fiber off-axis orientation and strain rate on the macroscopic property of a polymer matrix composite. During the analysis, AS4 fibers are considered as elastic solids, while the surrounding PEEK resin matrix exhibiting rate sensitivities are described using the modified Ramaswamy-Stouffer viscoplastic state variable model. The micromechanical method based on generalized model of cells has been used to analyze the representative volume element of composites. An acceptable agreement is observed between the model predictions and experimental results found in the literature. The research results show that the stress-strain curves are sensitive to the strain rate and the microstructure parameters play an important role in the behavior of polymer matrix.

  4. Behaviour of Cohesionless Soils During Cyclic Loading

    DEFF Research Database (Denmark)

    Shajarati, Amir; Sørensen, Kris Wessel; Nielsen, Søren Kjær

    Offshore wind turbine foundations are typically subjected to cyclic loading from both wind and waves, which can lead to unacceptable deformations in the soil. However, no generally accepted standardised method is currently available, when accounting for cyclic loading during the design of offshore...... wind turbine foundations. Therefore a literature study is performed in order to investigate existing research treating the behaviour of cohesionless soils, when subjected to cyclic loading. The behaviour of a soil subjected to cyclic loading is found to be dependent on; the relative density, mean...

  5. Research Article. Towards a tidal loading model for the Argentine-German Geodetic Observatory (La Plata

    Directory of Open Access Journals (Sweden)

    Richter A.

    2017-02-01

    Full Text Available We present a regionalized model of ocean tidal loading effects for the Argentine-German Geodetic Observatory in La Plata. It provides the amplitudes and phases of gravity variations and vertical deformation for nine tidal constituents to be applied as corrections to the observatory’s future geodetic observation data. This model combines a global ocean tide model with a model of the tides in the Río de la Plata estuary. A comparison with conventional predictions based only on the global ocean tide model reveals the importance of the incorporation of the regional tide model. Tidal loading at the observatory is dominated by the tides in the Atlantic Ocean. An additional contribution of local tidal loading in channels and groundwater is examined. The magnitude of the tidal loading is also reviewed in the context of the effects of solid earth tides, atmospheric loading and non-tidal loads.

  6. Modeling of fracture and durability of paste-bonded composite joints subjected to hygro-thermal-mechanical loading

    Science.gov (United States)

    Harris, David Lee

    The objective of the research is to characterize the behavior of composite/composite joints with paste adhesive using both experimental testing and analytical modeling. In comparison with the conventional tape adhesive, joining composites using paste adhesive provides several advantages. The carbon fiber laminate material systems employed in this study included IM7 carbon fibers and 977-3 epoxy matrix assembled in prepreg tape, and AS4 carbon fibers and 977-3 epoxy matrix as a five-harness satin weave. The adhesive employed was EA 9394 epoxy. All laminates and test specimens were fabricated and inspected by Boeing using their standard propriety procedures. Three types of test specimens were used in the program. They were bonded double-lap shear (DLS), bonded double cantilever beam (DCB) and bonded interlaminar tension (ILT) specimens. A group of specimens were conditioned at elevated temperature and humidity in an environmental chamber at Boeing's facility and their moisture absorption recorded with time. Specimens were tested at room temperature dry and elevated temperatures. DCB and DLS specimens were tested in fatigue as well as static conditions. Two-dimensional finite element models of the three configurations were developed for determining stresses and strains using the ABAQUS finite element package code. Due to symmetry, only the one-half of the specimen needed to be considered thus reducing computational time. The effect of the test fixture is not taken into account instead equivalent distributed stresses are applied directly on the composite laminates. For each of the specimen, the distribution of Mises stress and the first strain invariant J1 are obtained to identify potential failure locations within a specimen.

  7. The effects of wire diameter and an additional lateral wire on pin and tension-band fixation subjected to cyclic loads.

    Science.gov (United States)

    Neat, B; Kowaleski, M P; Litsky, A S; Boudrieau, R J

    2006-01-01

    Despite reports of frequent complications, pin and tension- band wire remains the most common repair of simple olecranon fractures and osteotomies. A recent mechanical study found wire diameter to be the key determinant of pin and tension-band construct strength; models with 1.25-mm wire were much stronger than those with standard 1.0-mm wire exposed to single loads to failure. Additionally, fixation strength was also increased when a lateral wire was used in combination with a standard figure-of-eight wire. The purpose of the present study was to assess any advantages provided by 1.25-mm wire or an additional lateral wire over 1.0-mm wire for pin and tension-band fixation subjected to cyclic loading. Pin and tension-band fixation was applied to plastic olecranon osteotomy models with three wire configurations: 1.0-mm figure-of-eight, 1.25-mm figure-of-eight, and combined 1.0-mm figure-of-eight and lateral. Cyclic load was applied while caudal osteotomy displacement was measured with an extensometer. The three groups were compared in terms of cycles to failure, mean minimum displacement, mean maximum displacement, and mean displacement per cycle. Models with an additional lateral wire survived significantly more cycles than those with a solitary 1.0-mm figure-of-eight wire, although caudal osteotomy displacements were not significantly different. Conversely, models with 1.25-mm wire allowed significantly smaller minimum and maximum displacements than those with 1.0-mm wire, but did not survive significantly more cycles. It therefore appears that clinical use of 1.25-mm wire may improve stability, while use of an additional lateral wire may improve durability.

  8. Current research on shear buckling and thermal loads with PASCO - Panel analysis and sizing code

    Science.gov (United States)

    Stroud, W. J.; Greene, W. H.; Anderson, M. S.

    1984-01-01

    The stiffened composite structural panel analysis and sizing code designated 'PASCO' encompasses both the generality required for the exploitation of composite materials' design flexibility and an accurate buckling analysis for the detection of complex buckling modes. PASCO can accordingly design for buckling, frequency, material strength, and panel stiffness requirements. Attention is given to an additional thermal loading design capability. Design studies illustrate the importance of the multiple load condition capability when thermal loads are present.

  9. Mechanical Properties and Real-Time Damage Evaluations of Environmental Barrier Coated SiC/SiC CMCs Subjected to Tensile Loading Under Thermal Gradients

    Science.gov (United States)

    Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

    2015-01-01

    SiC/SiC ceramic matrix composites (CMCs) require new state-of-the art environmental barrier coatings (EBCs) to withstand increased temperature requirements and high velocity combustion corrosive combustion gasses. The present work compares the response of coated and uncoated SiC/SiC CMC substrates subjected to simulated engine environments followed by high temperature mechanical testing to asses retained properties and damage mechanisms. Our focus is to explore the capabilities of electrical resistance (ER) measurements as an NDE technique for testing of retained properties under combined high heat-flux and mechanical loading conditions. Furthermore, Acoustic Emission (AE) measurements and Digital Image Correlation (DIC) were performed to determine material damage onset and accumulation.

  10. Crack initiation at V-notch tip subjected to in-plane mixed mode loading: An application of the fictitious notch rounding concept

    Directory of Open Access Journals (Sweden)

    F. Berto

    2015-10-01

    Full Text Available The fictitious notch rounding concept is applied for the first time to V-notches with root hole subjected to in-plane mixed mode loading. Out-of-bisector crack propagation is taken into account. The fictitious notch radius is determined as a function of the real notch radius the microstructural support length and the notch opening angle. Due to the complexity of the problem, a method based on the simple normal stress failure criterion has been used. It is combined with the maximum tangential stress criterion to determine the crack propagation angle. An analytical method based on Neuber's procedure has been developed. The method provides the values of the microstructural support factor as a function of the mode ratio and the notch opening angle. The support factor is considered to be independent of the microstructural support length. Finally, for comparison, the support factor is determined on a purely numerical basis by iterative analysis of FE models.

  11. Implants with an Oxidized Surface Placed Predominately in Soft Bone Quality and Subjected to Immediate Occlusal Loading: Results from an 11-Year Clinical Follow-Up.

    Science.gov (United States)

    Glauser, Roland

    2016-06-01

    The purpose of this clinical follow-up was to document the 11-year outcome of implants with a moderately rough oxidized surface subjected to immediate occlusal loading. Twenty-six of 38 patients enrolled in a 5-year prospective study were available for this follow-up analysis, with 33 restorations supported by 66 slightly tapered implants (Brånemark System MkIV, Nobel Biocare, Gothenburg, Sweden). The majority of implants were placed in posterior regions (88%) and into soft bone (76%). Parameters included cumulative survival rate (CSR), radiographic marginal bone level, bleeding on probing (BOP), intrasulcular counts of perio-pathogenic markers (DNA probes), and total bacterial load (TBL). The CSR was 97.1% at 11.2 years mean follow-up. Mean marginal bone remodeling was 0.47 mm (SD 1.09, n = 65) from 1 year postplacement to 11-year follow-up. BOP was absent at most sites (63.6%). No statistically significant differences in TBL or perio-pathogenic marker species were observed at implants and teeth. The results of the present follow-up show high long-term survival, stable marginal bone levels, and soft tissue outcomes of oxidized surface implants placed predominately in posterior regions and soft bone. The quantity and quality of intrasulcular microbiota were comparable at implants and teeth. © 2015 Wiley Periodicals, Inc.

  12. An empirical research on relationships between subjective judgement, technology acceptance tendency and knowledge transfer

    Science.gov (United States)

    Dai, Chien-Yun; Chen, Hsiao-Ming; Chen, Wan-Fei; Wu, Chia-Huei; Li, Guodong; Wang, Jiangtao

    2017-01-01

    The purpose of this study was to explore the relationships among employees' usage intention pertaining to mobile information devices, focusing on subjective judgement, technology acceptance tendency, information sharing behavior and information transfer. A research model was established to verify several hypotheses. The research model based on integrated concepts of knowledge management and technology acceptance modeling. Participants were employees of enterprises in Taiwan, selected by combining snowball and convenience sampling. Data obtained from 779 e-surveys. Multiple-regression analysis was employed for hypothesis verification. The results indicate that perceived ease-of-use of mobile devices was affected by computer self-efficacy and computer playfulness directly; meanwhile, perceived ease-of-use directly affects perceived usefulness. In addition, perceived ease-of-use and perceived usefulness can predict information-sharing behavior in a positive manner, and impact knowledge transfer as well. Based on the research findings, it suggested that enterprises should utilize mobile information devices to create more contact with customers and enrich their service network. In addition, it is recommended that managers use mobile devices to transmit key information to their staff and that they use these devices for problem-solving and decision-making. Further, the staff’s skills pertaining to the operation of mobile information devices and to fully implement their features are reinforced in order to inspire the users' knowledge transfer. Enhancing the playfulness of the interface is also important. In general, it is useful to promote knowledge transfer behavior within an organization by motivating members to share information and ideas via mobile information devices. In addition, a well-designed interface can facilitate employees' use of these devices. PMID:28886088

  13. An empirical research on relationships between subjective judgement, technology acceptance tendency and knowledge transfer.

    Science.gov (United States)

    Yuan, Yu-Hsi; Tsai, Sang-Bing; Dai, Chien-Yun; Chen, Hsiao-Ming; Chen, Wan-Fei; Wu, Chia-Huei; Li, Guodong; Wang, Jiangtao

    2017-01-01

    The purpose of this study was to explore the relationships among employees' usage intention pertaining to mobile information devices, focusing on subjective judgement, technology acceptance tendency, information sharing behavior and information transfer. A research model was established to verify several hypotheses. The research model based on integrated concepts of knowledge management and technology acceptance modeling. Participants were employees of enterprises in Taiwan, selected by combining snowball and convenience sampling. Data obtained from 779 e-surveys. Multiple-regression analysis was employed for hypothesis verification. The results indicate that perceived ease-of-use of mobile devices was affected by computer self-efficacy and computer playfulness directly; meanwhile, perceived ease-of-use directly affects perceived usefulness. In addition, perceived ease-of-use and perceived usefulness can predict information-sharing behavior in a positive manner, and impact knowledge transfer as well. Based on the research findings, it suggested that enterprises should utilize mobile information devices to create more contact with customers and enrich their service network. In addition, it is recommended that managers use mobile devices to transmit key information to their staff and that they use these devices for problem-solving and decision-making. Further, the staff's skills pertaining to the operation of mobile information devices and to fully implement their features are reinforced in order to inspire the users' knowledge transfer. Enhancing the playfulness of the interface is also important. In general, it is useful to promote knowledge transfer behavior within an organization by motivating members to share information and ideas via mobile information devices. In addition, a well-designed interface can facilitate employees' use of these devices.

  14. Research on dynamic creep strain and settlement prediction under the subway vibration loading.

    Science.gov (United States)

    Luo, Junhui; Miao, Linchang

    2016-01-01

    This research aims to explore the dynamic characteristics and settlement prediction of soft soil. Accordingly, the dynamic shear modulus formula considering the vibration frequency was utilized and the dynamic triaxial test conducted to verify the validity of the formula. Subsequently, the formula was applied to the dynamic creep strain function, with the factors influencing the improved dynamic creep strain curve of soft soil being analyzed. Meanwhile, the variation law of dynamic stress with sampling depth was obtained through the finite element simulation of subway foundation. Furthermore, the improved dynamic creep strain curve of soil layer was determined based on the dynamic stress. Thereafter, it could to estimate the long-term settlement under subway vibration loading by norms. The results revealed that the dynamic shear modulus formula is straightforward and practical in terms of its application to the vibration frequency. The values predicted using the improved dynamic creep strain formula closed to the experimental values, whilst the estimating settlement closed to the measured values obtained in the field test.

  15. Research of dynamic load balancing based on the UMTS-SGSN system

    Science.gov (United States)

    Wang, Furong; Teng, Zuwei

    2004-04-01

    During the distributed design of UMTS-SGSN system, the Dynamic Central Tasks Scheduling algorithm (DCTS) with good real-time property is researched to meet the hard requirements of bandwidth and latency of UMTS-SGSN system. Based on the assumption without task migration, Markov queuing network model is used to model UMTS-SGSN system instead of M/M/c queuing model. For single user with one PDP context, DCTS is optimal through the theoretic calculation and simulation. And for single user with not less than one PDP context, the performance of DCTS is discussed through the simulation. In the case of longer service time in data service, DCTS is compared with stochastic scheduling algorithm and cycle scheduling algorithm. Simulation results show that DCTS is better than other two algorithms, and when service time is shorter, three algorithms' performance is approximately same. The performances of the three algorithms in different service time are also analyzed by adjusting the parameter μ of the exponential distribution. Results show that exponential distribution's heavy-tailed effect of the service time leads to deteriorating the efficiency of load balancing and DCTS shall initiate less task migration and decrease system overhead.

  16. Loadings in thermal barrier coatings of jet engine turbine blades an experimental research and numerical modeling

    CERN Document Server

    Sadowski, Tomasz

    2016-01-01

    This book discusses complex loadings of turbine blades and protective layer Thermal Barrier Coating (TBC), under real working airplane jet conditions. They obey both multi-axial mechanical loading and sudden temperature variation during starting and landing of the airplanes. In particular, two types of blades are analyzed: stationary and rotating, which are widely applied in turbine engines produced by airplane factories.

  17. Comparison of Energy Dissipation, Stiffness, and Damage of Structural Oriented Strand Board (OSB, Conventional Gypsum, and Viscoelastic Gypsum Shearwalls Subjected to Cyclic Loads

    Directory of Open Access Journals (Sweden)

    Andrew S. Blasetti

    2012-06-01

    Full Text Available A key element in the seismic load resisting system of a wood framed structure is the shear wall which is typically sheathed on one side with plywood or oriented strand board (OSB and gypsum on the other. The shear capacity of gypsum sheathed shear walls is typically neglected in high seismic areas due to the susceptibility of conventional drywall screw connections to damage caused by earthquakes. The earthquake resistance of an innovative viscoelastic (VE gypsum shearwall is evaluated and compared to conventional structural and non-structural walls. Ten 8 ft × 8 ft wood framed wall specimens of three configurations [nailed-OSB, screw-gypsum, and VE polymer-gypsum] were subjected to a cyclic test protocol. The energy dissipation, stiffness, and damage characteristics of all shearwalls are reported herein. Testing results indicate the VE-gypsum walls can dissipate more energy than the OSB structural panels and 500% more energy that the conventional gypsum sheathed walls and contains a constant source of energy dissipation not seen in the structural and non-structural walls. The wall stiffness of the OSB wall degrades at a far greater rate that the VE gypsum wall and at continued cycling degrades below the VE wall stiffness. Unlike both of the conventional wall types, the VE wall showed no visible or audible signs of damage when subjected to shear displacements up to 1.

  18. MARKETING RESEARCH OF THE SUBJECTIVE AND MOTIVATIONAL CHARACTERISTICS OF CONSUMERS OF TOURIST SERVICES OF THE YAROSLAVL

    Directory of Open Access Journals (Sweden)

    Алексей Николаевич Минеев

    2013-04-01

    Full Text Available For today one of the most dynamically developing spheres is tourism. According to the Rosstat, the share of tourist sector in the total volume of GDP is already 4%, and with the allied industries - by 7%. The industry is fraught with deep potential and has the value of the national scale, but for further development it is necessary to understand the needs, desires, and motives of potential tourists at the level of separate territorial entities. Research devoted to the subject of the analysis of user characteristics and features of demand for tourist services is extremely small, which gives it the real theme of the novel.The relevance of the theme is determined by the analysis of the demand for tourist services. The aim of the work is a marketing analysis of the Yaroslavl consumers of tourism products. For realization of this goal, a study was conducted by the method of questioning. The survey has identified the most popular kinds of tourism, the main parameters and motives, which are used by consumers when planning your vacation and tourism, as well as describes and analyses the main types of consumers and their quantitative composition. Study of consumer characteristics will allow organizations to better Orient themselves in them and the values of the clients.DOI: http://dx.doi.org/10.12731/2218-7405-2013-1-27

  19. Discourse, Subject, and Agency. Linking Discourse Analysis and Biographical Research with the Help of the Concept of Articulation

    Directory of Open Access Journals (Sweden)

    Tina Spies

    2009-04-01

    Full Text Available For a significant period of time biographical research did not focus on the influence of discourses on biographical narratives. In contrast, discourse analysis often disregarded the subject-constituting impact of discourses. This article deals with the theoretical question of how to work with both: discourse and subject. Therefore, I will introduce Stuart HALL's concept of articulation. Since the early 1990's HALL has been working on questions of (cultural identity. In this context he developed an understanding of subjects that enables them not only to be seen as effects of discourses, but also allows focusing on discourses in subject conceptions. Neither biographical research nor discourse analysis In German speaking countries have embraced the work of HALL. But his concept of articulation could link biographical research and discourse analysis, and could also be used for further empirical work. URN: urn:nbn:de:0114-fqs0902369

  20. Guidelines to Classify Female Subject Groups in Sport-Science Research.

    Science.gov (United States)

    Decroix, Lieselot; De Pauw, Kevin; Foster, Carl; Meeusen, Romain

    2016-03-01

    To review current cycling-related sport-science literature to formulate guidelines to classify female subject groups and to compare this classification system for female subject groups with the classification system for male subject groups. A database of 82 papers that described female subject groups containing information on preexperimental maximal cycle-protocol designs, terminology, biometrical and physiological parameters, and cycling experience was analyzed. Subject groups were divided into performance levels (PLs), according to the nomenclature. Body mass, body-mass index, maximal oxygen consumption (VO2max), peak power output (PPO), and training status were compared between PLs and between female and male PLs. Five female PLs were defined, representing untrained, active, trained, well-trained, and professional female subjects. VO2max and PPO significantly increased with PL, except for PL3 and PL4 (P groups. Relative VO2max is the most cited parameter for female subject groups and is proposed as the principal parameter to classify the groups. This systematic review shows the large variety in the description of female subject groups in the existing literature. The authors propose a standardized preexperimental testing protocol and guidelines to classify female subject groups into 5 PLs based on relative VO2max, relative PPO, training status, absolute VO2max, and absolute PPO.

  1. An empirical research on relationships between subjective judgement, technology acceptance tendency and knowledge transfer

    National Research Council Canada - National Science Library

    Yu-Hsi Yuan; Sang-Bing Tsai; Chien-Yun Dai; Hsiao-Ming Chen; Wan-Fei Chen; Chia-Huei Wu; Guodong Li; Jiangtao Wang

    2017-01-01

    The purpose of this study was to explore the relationships among employees' usage intention pertaining to mobile information devices, focusing on subjective judgement, technology acceptance tendency...

  2. Analysis of roof membranes damaged by mechanical and climatic loads – pilot research

    Directory of Open Access Journals (Sweden)

    Čurpek Jakub

    2017-01-01

    Full Text Available Realization of roof construction has many hidden risks, especially in buildings with diverse architecture. There is a problem about cooperation of individual works (vertical and horizontal constructions on roof in this type of architecture, during the process of realization. Purpose of this research is to reveal risks in form of the group of major source of defects by mechanical damages. The most often types of mechanical damages were chosen in this research, which then were applied on individual types of roof membranes. Response of this damage was found out during the test procedure of water pressure by special laboratory machines. Furthermore, samples of roof membranes were subjected to the Impact test, which was actually focused on damage by hailstone impact from the atmosphere. The final outcomes of the measurements show that the material composition of each roof membrane can influence their whole waterproofing after application of certain type of mechanical damage. In the Impact test, samples were suffered from impact of the hails. This test signified that the choice of base material of thermal insulation below the roof membrane plays an important role.

  3. Plug-Load Control and Behavioral Change Research in GSA Office Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, I.; Cutler, D.; Sheppy, M.

    2012-10-01

    The U.S. General Services Administration (GSA) owns and leases over 354 million square feet (ft2) of space in over 9,600 buildings [1]. GSA is a leader among federal agencies in aggressively pursuing energy efficiency (EE) opportunities for its facilities and installing renewable energy (RE) systems to provide heating, cooling, and power to these facilities. According to several energy assessments of GSA's buildings conducted by the National Renewable Energy Laboratory (NREL), plug-loads account for approximately 21% of the total electricity consumed within a standard GSA Region 3 office building. This study aims to provide insight on how to effectively manage plug-load energy consumption and attain higher energy and cost savings for plug-loads. As GSA improves the efficiency of its building stock, plug-loads will become an even greater portion of its energy footprint.

  4. A Meta-Analysis of Single-Subject Research on Behavioral Momentum to Enhance Success in Students with Autism

    Science.gov (United States)

    Cowan, Richard J.; Abel, Leah; Candel, Lindsay

    2017-01-01

    We conducted a meta-analysis of single-subject research studies investigating the effectiveness of antecedent strategies grounded in behavioral momentum for improving compliance and on-task performance for students with autism. First, we assessed the research rigor of those studies meeting our inclusionary criteria. Next, in order to apply a…

  5. Myofascial treatment for patients with acetabular labral tears: a single-subject research design study.

    Science.gov (United States)

    Cashman, Glenn E; Mortenson, W Ben; Gilbart, Michael K

    2014-08-01

    Single-subject research design using 4 consecutive patients. To assess whether treatment using soft tissue therapy (ART or Active Release Technique), stretching, and strengthening of the hip abductors, hip external rotators, and tensor fascia latae muscles reduces pain and improves self-reported hip function in patients with acetabular labral tears who also have posterolateral hip pain of suspected myofascial origin. Acetabular labral tears cause pain in some but not all patients. Pain commonly presents anteriorly but may also present posteriorly and laterally. The standard of care is arthroscopic repair, which helps many but not all patients. It is possible that these patients may present with extra-articular contributions to their pain, such as myofascial pain, making their clinical presentation more complex. No previous study has assessed soft tissue therapy as a treatment option for this subset of patients. This A-B-A design used repeated measures of the Hip Outcome Score and visual analog scale for pain. Four patients were treated for 6 to 8 weeks, using a combination of soft tissue therapy, stretching, and strengthening for the hip abductors, external rotators, and tensor fascia latae. Data were assessed visually, statistically, and by comparing mean differences before and after intervention. All 4 patients experienced both statistically significant and clinically meaningful improvement in posterolateral hip pain and hip-related function. Three patients also experienced reduction in anteromedial hip pain. Myofascial hip pain may contribute to hip-related symptoms and disability in patients with acetabular labral tears and posterolateral hip pain. These patients may benefit from soft tissue therapy combined with stretching and strengthening exercises targeting the hip abductors, tensor fascia latae, and hip external rotator muscles. Level of Evidence Therapy, level 4.

  6. The human capacity to reflect and decide: bioethics and the reconfiguration of the research subject in the British biomedical sciences.

    Science.gov (United States)

    Reubi, David

    2012-06-01

    This article examines how a fundamental element of the British bioethical assemblage - the literature on informed consent published between 1980 and 2000, a period when bioethics became a powerful force in the UK--has influenced contemporary understandings of the research subject. Drawing on Foucault, the article argues that this corpus of texts has created a sphere of possibilities in which research subjects can imagine themselves as human beings who reflect and decide whether they want to participate in medical experimentation. In particular, it shows how the narratives found in these texts portray relationships between researchers and their human subjects as 'paternalistic', and calls for their replacement by new, more ethical relationships characterized by both 'dialogue' and 'respect' and articulated around subjects who can 'think and take decisions'. It also discusses the different strategies- using patient information sheets, a list of possible questions and invitations to take time to reflect--which the bioethical literature has developed in order to realise these new, ethical relationships. As the article suggests, these narratives and strategies provide researchers and research subjects with models and examples of how to interact with each other that are very different from the ones that prevailed before the emergence of bioethics.

  7. The impact factor-based quality assessment of biomedical research institutes in Iran: effect of impact factor normalization by subject.

    Science.gov (United States)

    Rezaei-Ghaleh, Nasrollah; Azizi, Fereidoun

    2007-04-01

    The journal impact factor is increasingly employed to evaluate the quality of scientific research. This is in contrary to its critical limitations, e.g., its marked variation across scientific disciplines. This study was conducted to describe, in both quantitative and qualitative terms, the contribution of Iranian universities and research institutes to biomedical publications in 2004 and to examine the possible effect of impact factor normalization by subject on their rankings. The Iranian biomedical articles were recruited from Thomson Science Citation Index Expanded and PubMed databases according to Thomson Scientific subject categorization of journals. Three subject-normalized impact factors were employed: rank-normalized impact factor, journal to field impact score, and standardized impact factor. Tehran and Shiraz Universities of Medical Sciences and University of Tehran were the top three institutes regarding the sum of impact factor in 2004. On the basis of the mean crude impact factor, Sharif University of Technology, University of Shiraz, and Baqiyatollah University were ranked as the first to third. However, the subject normalization of impact factor made some considerable changes in impact factor-based rankings of research institutes. The Iranian scientific community and science development policy makers are recommended to employ subject-normalized impact factor, rather than crude impact factor, in quality assessment of biomedical research held in various academic and research institutes.

  8. Employees as Individually and Collectively Acting Subjects-Key Contributions from Nordic Working Life Research

    National Research Council Canada - National Science Library

    Peter Hasle; Ole Henning Sørensen

    2013-01-01

    .... The paper poses the question whether the distinct character of the Nordic societies has generated working life research that is clearly distinguishable from similar research in other countries...

  9. Subjective Time Perceptions and Aging Well: A Review of Concepts and Empirical Research - A Mini-Review.

    Science.gov (United States)

    Gabrian, Martina; Dutt, Anne J; Wahl, Hans-Werner

    2017-01-01

    understanding of human development across the lifespan. To this end, we call for theoretical and empirical interlinkages between yet loosely connected conceptual developments related to subjective time. These endeavors should be paralleled by an extension of methodological procedures (e.g., implementation of longitudinal research designs as well as a focus on the oldest-old) in order to inform a "lifespan theory of subjective time." © 2017 S. Karger AG, Basel.

  10. EFFECT OF FLIPPED LEARNING ON COGNITIVE LOAD: A HIGHER EDUCATION RESEARCH

    Directory of Open Access Journals (Sweden)

    Celal Karaca

    2017-01-01

    Full Text Available The purpose of this study is to determine the effect of the flipped learning method on the cognitive load of the students. The study was conducted with a sample of 160 people who were trained in Department of Mechanical Engineering for algorithms and programming courses at a higher education level. The study, which lasted for 8 weeks, has a semi-experimental design. A 9-point scale developed by Paas and Van Merrienboer (1993 was used for cognitive load measurements. At the end of the weekly courses, the scale was filled by the experimental and control groups. Independent sample t test was applied through SPSS 24 program to the obtained data. In both instances, the cognitive load in the experimental group in which the flipped learning method was applied was found to be lower than the cognitive load in the control group in which traditional face-to-face training was applied. As a result, it can be said that flipped learning, if well structured, is a method reducing cognitive load.

  11. The Research Doesn't Always Apply: Practical Solutions to Evidence-Based Training-Load Monitoring in Elite Team Sports.

    Science.gov (United States)

    Burgess, Darren J

    2017-04-01

    Research describing load-monitoring techniques for team sport is plentiful. Much of this research is conducted retrospectively and typically involves recreational or semielite teams. Load-monitoring research conducted on professional team sports is largely observational. Challenges exist for the practitioner in implementing peer-reviewed research into the applied setting. These challenges include match scheduling, player adherence, manager/coach buy-in, sport traditions, and staff availability. External-load monitoring often attracts questions surrounding technology reliability and validity, while internal-load monitoring makes some assumptions about player adherence, as well as having some uncertainty around the impact these measures have on player performance This commentary outlines examples of load-monitoring research, discusses the issues associated with the application of this research in an elite team-sport setting, and suggests practical adjustments to the existing research where necessary.

  12. Survey-guided load research: An end-use analysis methodology test

    Energy Technology Data Exchange (ETDEWEB)

    Warwick, W.M.

    1993-08-01

    Energy use by end-use equipment is a function of the rated capacity of the equipment, frequency of use, and duration of each use. Many end used include multiple states, each with a different capacity, frequency, and duration. Some equipment provides benefits that are related to other uses, resulting in an indirect linkage between the primary energy-using equipment and the end use. Water heaters are one example. End-use metering of energy-using equipment provides the most accurate measure of energy use. Nevertheless, this energy-use ``signal`` is buried in background ``noise`` due to variations in the capacity, frequency, and duration of each end use and end user. Reliable estimates of energy use depend on a variety of methods to increase the ``signal-to-noise`` ratio (i.e., reduce the variance). Research of the energy consumption of household end-uses contains some inherent sampling problems: intrusiveness, cost, extensive data generated, analyses are time and computationally intensive. The goal of the methodology test described in this paper was to address these problems through a method that focused end-use analyses on a limited set of issues and data for program evaluation purposes. The approach tested used a detailed survey of end-use metered subjects to identify the pattern of end-use behavior as an alternative to estimating the frequency and duration of each use from the end-use data itself.

  13. A PROPOSAL FOR AN ASSESSMENT METHOD OF THE DYNAMIC RESISTANCE OF CONCRETE SLAB VIADUCTS SUBJECTED TO IMPACT LOADS CAUSED BY MINING TREMORS

    Directory of Open Access Journals (Sweden)

    Janusz RUSEK

    Full Text Available The article presents a method for assessing dynamic resistance of existing reinforced concrete slab road viaducts subjected to mining tremors. For this purpose there are formulated six criteria to determine the maximum permissible value of the component ground vibrations (ax,dop, ay,dop, az,dop.Within each criterion, a reference is made to the most critical components, for which for which the Author has formulated strength and kinematic conditions, reflecting the behaviour of the structure under dynamic excitation caused by mining tremor. The permissible range of structural behaviour was set by comparing the effects of load combinations adopted at the design stage with a seismic combination proposed in [12]. In the field of dynamic analysis the response spectrum method was used, taking into account the guidelines for the adaptation of Eurocode 8 for the calculation the response of construction to the influence of mining tremors. Finally, in accordance with the established procedure calculations were carried out and and results are presented for a sample reinforced concrete slab road viaduct.

  14. Neither Objective nor Neutral? Reflecting on My Subjectivity throughout the Research Process in Takiwa School.

    Science.gov (United States)

    Carpenter, Vicki

    An educational researcher describes and reflects on a qualitative research project she conducted, focusing on her positioning, neutrality, and objectivity throughout the research process and during subsequent data analysis. The research took place in a K-12 school in a remote rural New Zealand community inhabited by Maori, 1970s…

  15. Test method research on weakening interface strength of steel - concrete under cyclic loading

    Science.gov (United States)

    Liu, Ming-wei; Zhang, Fang-hua; Su, Guang-quan

    2018-02-01

    The mechanical properties of steel - concrete interface under cyclic loading are the key factors affecting the rule of horizontal load transfer, the calculation of bearing capacity and cumulative horizontal deformation. Cyclic shear test is an effective method to study the strength reduction of steel - concrete interface. A test system composed of large repeated direct shear test instrument, hydraulic servo system, data acquisition system, test control software system and so on is independently designed, and a set of test method, including the specimen preparation, the instrument preparation, the loading method and so on, is put forward. By listing a set of test results, the validity of the test method is verified. The test system and the test method based on it provide a reference for the experimental study on mechanical properties of steel - concrete interface.

  16. Research on stratified evolution of composite materials under four-point bending loading

    Science.gov (United States)

    Hao, M. J.; You, Q. J.; Zheng, J. C.; Yue, Z.; Xie, Z. P.

    2017-12-01

    In order to explore the effect of stratified evolution and delamination on the load capacity and service life of the composite materials under the four-point bending loading, the artificial tectonic defects of the different positions were set up. The four-point bending test was carried out, and the whole process was recorded by acoustic emission, and the damage degree of the composite layer was judged by the impact accumulation of the specimen - time-amplitude history chart, load-time-relative energy history chart, acoustic emission impact signal positioning map. The results show that the stratified defects near the surface of the specimen accelerate the process of material failure and expansion. The location of the delamination defects changes the bending performance of the composites to a great extent. The closer the stratification defects are to the surface of the specimen, the greater the damage, the worse the service capacity of the specimen.

  17. Research on improvement of power quality of Micro - grid based on SVG pulse load

    Science.gov (United States)

    Lv, Chuang; Xie, Pu

    2017-05-01

    Pulse load will make the micro-grid public bus power to produce a high peak pulse due to its cyclical pulsation characteristics,, and make the micro-grid voltage fluctuations, frequency fluctuations, voltage and current distortion, power factor reduction and other adverse effects. In order to suppress the adverse effects of the pulse load on the microgrid and improve the power quality of the microgrid, this paper established the SVG simulation model in Matlab / Simulink environment, the superiority of SVG is verified by comparing the improvement of power quality before and after adding the SVG to microgrid system. The results show that the SVG model can suppress the adverse effects effectively of the pulse load on the microgrid, which is of great value and significance to the reactive power compensation and harmonic suppression of the microgrid.

  18. From the ideal market to the ideal clinic: constructing a normative standard of fairness for human subjects research.

    Science.gov (United States)

    Phillips, Trisha

    2011-02-01

    Preventing exploitation in human subjects research requires a benchmark of fairness against which to judge the distribution of the benefits and burdens of a trial. This paper proposes the ideal market and its fair market price as a criterion of fairness. The ideal market approach is not new to discussions about exploitation, so this paper reviews Wertheimer's inchoate presentation of the ideal market as a principle of fairness, attempt of Emanuel and colleagues to apply the ideal market to human subjects research, and Ballantyne's criticisms of both the ideal market and the resulting benchmark of fairness. It argues that the criticism of this particular benchmark is on point, but the rejection of the ideal market is mistaken. After presenting a complete account of the ideal market, this paper proposes a new method for applying the ideal market to human subjects research and illustrates the proposal by considering a sample case.

  19. Diafragmas horizontais de piso em madeira, confeccionados com chapas de OSB e vigas I, submetido ao carregamento vertical = Wood light-frame floor diaphragms, made with OSB panels and Ijoists, subjected to vertical loads

    Directory of Open Access Journals (Sweden)

    Altevir Castro dos Santos

    2007-07-01

    Full Text Available Este trabalho aborda construções em madeira sob a ótica de sistemas com estruturas leves; apresenta análise computacional por meio de modelagem pelo método de elementos finitos de diafragmas de piso e vigas I, submetidas a ensaio de flexão a quatro pontos. O objetivo geral é avaliar a resistência e a rigidez de diafragmas horizontais,construídos em Sistemas Leves de Madeira, quando submetidos a ações verticais. As análises foram realizadas por meio do programa computacional SAP2000 e foram avaliadas as influências dos seguintes parâmetros: espaçamento entre vigas que constituem os elementosde ossatura do diafragma horizontal e o espaçamento entre pregos de fixação do contrapiso, composto por chapas de OSB – Oriented Strand Board. Ao final do trabalho, comparam-se os resultados obtidos a partir das análises numérica e teórica, e são apresentadas algumasconclusões.Wood light-frame floor diaphragms, made with OSB panels and I-joists, subjected to vertical loads. This work is focused on lightweight woodframe constructions, and presents a finite element modeling of floor diaphragms and wood I-joists subjected to four-point bending. It presents the results of experimental tests on wood I-joists subjected to vertical loads. The main goal of this research is to evaluate the resistance and rigidity of wood light-frame floor diaphragms, when subjected to monotonic vertical forces acting in the plane of the floor. The analyses were performed using the SAP2000 computer program and tested with diferent constructive arrangements, and the influence of the following variables were examined: distance between wood I-joists, and distance between nails around the perimeter of the OSB boards. Finally, a comparison between analytical and numerical results is performed.

  20. The Deaconess Informed Consent Comprehension Test: an assessment tool for clinical research subjects.

    Science.gov (United States)

    Miller, C K; O'Donnell, D C; Searight, H R; Barbarash, R A

    1996-01-01

    We developed an instrument to assess comprehension of informed consent information among 275 adults entering one of four ambulatory trials. At the conclusion of trial enrollment, subjects rated their understanding of the information presented and completed the Deaconess Informed Consent Comprehension Test (DICCT). Subjects completed the vocabulary subtest of the revised Weschler Adult Intelligence Scale (WAIS-R) and the reading subtest of the revised Wide Range Achievement Test (WRAT-R). The DICCT for 50 subjects was scored by 2 blinded investigators. Interrater agreement was 0.84 (df = 49, p < 0.001). To investigate the DICCT's potential validity, its scores were correlated with WAIS-R vocabulary scores (r = 0.44, df = 199, p < 0.01) and WRAT-R reading scores (r = 0.39, df = 268, p < 0.01). Understanding of consent information was rated as thorough by 70% of subjects. The mean +/- SD DICCT score was 20.4 +/- 3.9. The DICCT is a reliable instrument to assess comprehension of informed consent information. There is preliminary evidence for the scale's validity. The subjects believed that they had greater understanding of study information than was shown by the DICCT.