WorldWideScience

Sample records for subsequent academic buoyancy

  1. Is academic buoyancy anything more than adaptive coping?

    Science.gov (United States)

    Putwain, David W; Connors, Liz; Symes, Wendy; Douglas-Osborn, Erica

    2012-05-01

    Academic buoyancy refers to a positive, constructive, and adaptive response to the types of challenges and setbacks experienced in a typical and everyday academic setting. In this project we examined whether academic buoyancy explained any additional variance in test anxiety over and above that explained by coping. Two hundred and ninety-eight students in their final two years of compulsory schooling completed self-report measures of academic buoyancy, coping, and test anxiety. Results suggested that buoyancy was inversely related to test anxiety and unrelated to coping. With the exception of test-irrelevant thoughts, test anxiety was positively related to avoidance coping and social support. Test-irrelevant thoughts were inversely related to task focus, unrelated to social support, and positively related to avoidance. A hierarchical regression analysis showed that academic buoyancy explained a significant additional proportion of variance in test anxiety when the variance for coping had already been accounted for. These findings suggest that academic buoyancy can be considered as a distinct construct from that of adaptive coping.

  2. Academic Buoyancy and Academic Outcomes: Towards a Further Understanding of Students with Attention-Deficit/Hyperactivity Disorder (ADHD), Students without ADHD, and Academic Buoyancy Itself

    Science.gov (United States)

    Martin, Andrew J.

    2014-01-01

    Background: Academic buoyancy is students' capacity to successfully overcome setback and challenge that is typical of the ordinary course of everyday academic life. It may represent an important factor on the psycho-educational landscape assisting students who experience difficulties in school and schoolwork. Aims: This study investigated the…

  3. Academic Buoyancy Mediates Academic Anxiety's Effects on Learning Strategies: An Investigation of English- and Chinese-Speaking Australian Students

    Science.gov (United States)

    Collie, Rebecca J.; Ginns, Paul; Martin, Andrew J.; Papworth, Brad

    2017-01-01

    A primary goal our study was to explore whether relations between academic anxiety and students' use of a range of learning strategies (memorisation, elaboration, personal best [PB] goals and cooperation) were mediated by academic buoyancy. We were also interested in extending knowledge of anxiety and its role in students' learning strategy use.…

  4. "'Sink or Swim': Buoyancy and Coping in the Cognitive Test Anxiety--Academic Performance Relationship"

    Science.gov (United States)

    Putwain, David W.; Daly, Anthony L.; Chamberlain, Suzanne; Sadreddini, Shireen

    2016-01-01

    This study explores the relationship between students' self-report levels of cognitive test anxiety (worry), academic buoyancy (withstanding and successfully responding to routine school challenges and setbacks), coping processes and their achieved grades in high-stakes national examinations at the end of compulsory schooling. The sample comprised…

  5. Fitness Change and Subsequent Academic Performance in Adolescents

    Science.gov (United States)

    Chen, Li-Jung; Fox, Kenneth R.; Ku, Po-Wen; Taun, Chih-Yang

    2013-01-01

    Background: This study examined the association between fitness change and subsequent academic performance in Taiwanese schoolchildren from 7th grade to 9th grade. Methods: The 7th graders from 1 junior high school district participated in this study (N=669). Academic performance was

  6. A longitudinal study of childhood obesity, weight status change, and subsequent academic performance in Taiwanese children.

    Science.gov (United States)

    Chen, Li-Jung; Fox, Kenneth R; Ku, Po-Wen; Wang, Ching-Hui

    2012-09-01

    This study examined the association among childhood obesity, weight status change, and subsequent academic performance at 6-year follow-up. First-grade students from one elementary school district in Taichung City, Taiwan were followed for 6 years (N = 409). Academic performance was extracted from the school records at the end of each grade. Weight and height were measured at the beginning of each grade. A weight change variable was created based on each child's weight status difference at grades 1 and 6. A multivariate linear regression model for predicting academic performance at grade 6 was developed with adjustment for individual characteristics and family factors. A latent growth curve (LGC) showed the association between changes in body mass index (BMI) and in academic performance across a 6-year period. BMI in children increased significantly across 6 years. The rate of increase in BMI over 6 years was higher for children with higher baseline BMIs than it was for children with lower baseline BMIs. However, BMI changes were not significantly associated with changes of academic performance. There was no significant relationship between initial obesity or change in weight status and subsequent academic performance. It appears that either being or becoming overweight/obese did not impact academic achievement for these Taiwanese children. © 2012, American School Health Association.

  7. Neutral Buoyancy Laboratory (NBL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutral Buoyancy Laboratory (NBL) is an astronaut training facility and neutral buoyancy pool operated by NASA and located at the Sonny Carter Training Facility,...

  8. Center of buoyancy definition

    International Nuclear Information System (INIS)

    Sandberg, V.

    1988-12-01

    The center of buoyancy of an arbitrary shaped body is defined in analogy to the center of gravity. The definitions of the buoyant force and center of buoyancy in terms of integrals over the area of the body are converted to volume integrals and shown to have simple intuitive interpretations

  9. Exercise Equipment: Neutral Buoyancy

    Science.gov (United States)

    Shackelford, Linda; Valle, Paul

    2016-01-01

    Load Bearing Equipment for Neutral Buoyancy (LBE-NB) is an exercise frame that holds two exercising subjects in position as they apply counter forces to each other for lower extremity and spine loading resistance exercises. Resistance exercise prevents bone loss on ISS, but the ISS equipment is too massive for use in exploration craft. Integrating the human into the load directing, load generating, and motion control functions of the exercise equipment generates safe exercise loads with less equipment mass and volume.

  10. Wave Dragon Buoyancy Regulation Study

    DEFF Research Database (Denmark)

    Jakobsen, Jens; Kofoed, Jens Peter

    Wave Dragon is a wave energy converter, which was deployed offshore at Nissum Bredning in Denmark in 2003. The experience gained from operating Wave Dragon during 2003 and 2004 has shown that the buoyancy regulation system can be improved in a number of ways. This study describes the current...

  11. Does academic performance in the premedical year predict the performance of the medical student in subsequent years?

    Directory of Open Access Journals (Sweden)

    Abdulrahman M Al-Mazrou

    2008-01-01

    Conclusion: Our results support the prerequisite of a minimum GPA in the premedical year before proceeding to the higher levels. The GPA of premedical year is a useful predictor of students who need close monitoring and academic support. The use of GPA in the premedical year for admission into medical colleges should help optimize the use of resources and reduce student wastage.

  12. Academically Buoyant Students Are Less Anxious about and Perform Better in High-Stakes Examinations

    Science.gov (United States)

    Putwain, David W.; Daly, Anthony L.; Chamberlain, Suzanne; Sadreddini, Shireen

    2015-01-01

    Background: Prior research has shown that test anxiety is negatively related to academic buoyancy, but it is not known whether test anxiety is an antecedent or outcome of academic buoyancy. Furthermore, it is not known whether academic buoyancy is related to performance on high-stakes examinations. Aims: To test a model specifying reciprocal…

  13. 14 CFR 29.755 - Hull buoyancy.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull buoyancy. 29.755 Section 29.755... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.755 Hull buoyancy. Water-based and amphibian rotorcraft. The hull and auxiliary floats, if used, must have enough...

  14. Academic Performance in Children of Mothers With Schizophrenia and Other Severe Mental Illness, and Risk for Subsequent Development of Psychosis: A Population-Based Study.

    Science.gov (United States)

    Lin, Ashleigh; Di Prinzio, Patsy; Young, Deidra; Jacoby, Peter; Whitehouse, Andrew; Waters, Flavie; Jablensky, Assen; Morgan, Vera A

    2017-01-01

    We examined the academic performance at age 12 years of children of mothers diagnosed with schizophrenia or other severe mental illness using a large whole-population birth cohort born in Western Australia. We investigated the association between academic performance and the subsequent development of psychotic illness. The sample comprised 3169 children of mothers with severe mental illness (schizophrenia, bipolar disorder, unipolar major depression, delusional disorder or other psychoses; ICD-9 codes 295-298), and 88 353 children of comparison mothers without known psychiatric morbidity. Academic performance of children was indexed on a mandatory state-wide test of reading, spelling, writing and numeracy. A larger proportion of children (43.1%) of mothers with severe mental illness performed below the acceptable standard than the reference group (30.3%; children of mothers with no known severe mental illness). After adjusting for covariates, children of mothers with any severe mental illness were more likely than the reference group to perform below-benchmark on all domains except reading. For all children, poor spelling was associated with the later development of psychosis, but particularly for those at familial risk for severe mental illness (hazard ratio [HR] = 1.81; 95% CI for HR = 1.21, 2.72). Children of mothers with a severe mental illness are at increased risk for sub-standard academic achievement at age 12 years, placing these children at disadvantage for the transition to secondary school. For children with familial risk for severe mental illness, very poor spelling skills at age 12 years may be an indicator of risk for later psychotic disorder. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. Academic Performance in Children of Mothers With Schizophrenia and Other Severe Mental Illness, and Risk for Subsequent Development of Psychosis: A Population-Based Study

    Science.gov (United States)

    Lin, Ashleigh; Di Prinzio, Patsy; Young, Deidra; Jacoby, Peter; Whitehouse, Andrew; Waters, Flavie; Jablensky, Assen; Morgan, Vera A.

    2017-01-01

    Objective: We examined the academic performance at age 12 years of children of mothers diagnosed with schizophrenia or other severe mental illness using a large whole-population birth cohort born in Western Australia. We investigated the association between academic performance and the subsequent development of psychotic illness. Method: The sample comprised 3169 children of mothers with severe mental illness (schizophrenia, bipolar disorder, unipolar major depression, delusional disorder or other psychoses; ICD-9 codes 295–298), and 88 353 children of comparison mothers without known psychiatric morbidity. Academic performance of children was indexed on a mandatory state-wide test of reading, spelling, writing and numeracy. Results: A larger proportion of children (43.1%) of mothers with severe mental illness performed below the acceptable standard than the reference group (30.3%; children of mothers with no known severe mental illness). After adjusting for covariates, children of mothers with any severe mental illness were more likely than the reference group to perform below-benchmark on all domains except reading. For all children, poor spelling was associated with the later development of psychosis, but particularly for those at familial risk for severe mental illness (hazard ratio [HR] = 1.81; 95% CI for HR = 1.21, 2.72). Conclusions: Children of mothers with a severe mental illness are at increased risk for sub-standard academic achievement at age 12 years, placing these children at disadvantage for the transition to secondary school. For children with familial risk for severe mental illness, very poor spelling skills at age 12 years may be an indicator of risk for later psychotic disorder. PMID:27131155

  16. Non-Uniqueness of the Point of Application of the Buoyancy Force

    Science.gov (United States)

    Kliava, Janis; Megel, Jacques

    2010-01-01

    Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the…

  17. New Work Demands in Higher Education. A Study of the Relationship between Excessive Workload, Coping Strategies and Subsequent Health among Academic Staff

    Science.gov (United States)

    Melin, Marika; Astvik, Wanja; Bernhard-Oettel, Claudia

    2014-01-01

    This study investigates the relationship between the work conditions in higher education work settings, the academic staff's strategies for handling excessive workload and impact on well-being and work-life balance. The results show that there is a risk that staff in academic work places will start using compensatory coping strategies to deal with…

  18. An Analysis of Tax Buoyancy Rates

    Directory of Open Access Journals (Sweden)

    Farooq Rasheed

    2006-10-01

    Full Text Available By using econometric techniques for estimating tax elasticities, this paper findssignificant but low tax buoyancy rates for GDP, M0 and volume of trade. Surprisingly,the theoretically important factor of tax evasion (SFTR was found to be ineffective. Thisindicates that SFTR is not an adequate measure of tax evasion. There is no significantassociation between tax revenue growth and investment, credit, public debt and inflation.This illustrates the weakness of the tax regime in Pakistan.

  19. Energy spectrum of buoyancy-driven turbulence

    KAUST Repository

    Kumar, Abhishek

    2014-08-25

    Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Πu, we demonstrate that, for stably stratified flows, the kinetic energy spectrum Eu(k)∼k-11/5, the potential energy spectrum Eθ(k)∼k-7/5, and Πu(k)∼k-4/5 are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential energy by buoyancy. For weaker buoyancy, this conversion is weak, hence Eu(k) follows Kolmogorov\\'s spectrum with a constant energy flux. For Rayleigh-Bénard convection, we show that the energy supply rate by buoyancy is positive, which leads to an increasing Πu(k) with k, thus ruling out Bolgiano-Obukhov scaling for the convective turbulence. Our numerical results show that convective turbulence for unit Prandt number exhibits a constant Πu(k) and Eu(k)∼k-5/3 for a narrow band of wave numbers. © 2014 American Physical Society.

  20. Non-uniqueness of the point of application of the buoyancy force

    International Nuclear Information System (INIS)

    Kliava, Janis; Megel, Jacques

    2010-01-01

    Even though the buoyancy force (also known as the Archimedes force) has always been an important topic of academic studies in physics, its point of application has not been explicitly identified yet. We present a quantitative approach to this problem based on the concept of the hydrostatic energy, considered here for a general shape of the cross-section of a floating body and for an arbitrary angle of heel. We show that the location of the point of application of the buoyancy force essentially depends (i) on the type of motion experienced by the floating body and (ii) on the definition of this point. In a rolling/pitching motion, considerations involving the rotational moment lead to a particular dynamical point of application of the buoyancy force, and for some simple shapes of the floating body this point coincides with the well-known metacentre. On the other hand, from the work-energy relation it follows that in the rolling/pitching motion the energetical point of application of this force is rigidly connected to the centre of buoyancy; in contrast, in a vertical translation this point is rigidly connected to the centre of gravity of the body. Finally, we consider the location of the characteristic points of the floating bodies for some particular shapes of immersed cross-sections. The paper is intended for higher education level physics teachers and students.

  1. Buoyancy Driven Natural Ventilation through Horizontal Openings

    OpenAIRE

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions...

  2. Importance of First and Second Authorship in Assessing Citation-Based Scholarly Activity of US Radiation Oncology Residents and Subsequent Choice of Academic Versus Private Practice Career.

    Science.gov (United States)

    McClelland, Shearwood; Mitin, Timur; Jagsi, Reshma; Thomas, Charles R; Jaboin, Jerry J

    2018-06-20

    The Hirsch index (h-index) has been shown to correlate with radiation oncology residents' having a first job in academics versus private practice, but it is limited by its inability to distinguish between the differing significance of coauthor roles in articles. A list of 2016 radiation oncology resident graduates and their postresidency career choices was compiled. The Scopus bibliometric citation database was then searched to collect h-index data for articles limited to first author only (h f ) and first or second-author only (h s ) for each resident. Mean h f was 2.06 for all resident graduates, and mean h s was 2.77. Residents with PhDs had significantly higher h f (3.11 versus 1.76, P gender. Only 10% of graduates without any first- and/or second-author articles cited at least once secured academic jobs. These findings indicate that stratifying publications by first or second authorship when developing benchmarks for evaluating resident productivity and postresidency career type may be useful. Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  3. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  4. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  5. Astronaut Training in the Neutral Buoyancy Simulator

    Science.gov (United States)

    1993-01-01

    This photograph shows an STS-61 astronaut training for the Hubble Space Telescope (HST) servicing mission (STS-61) in the Marshall Space Flight Center's (MSFC's) Neutral Buoyancy Simulator (NBS). Two months after its deployment in space, scientists detected a 2-micron spherical aberration in the primary mirror of the HST that affected the telescope's ability to focus faint light sources into a precise point. This imperfection was very slight, one-fiftieth of the width of a human hair. A scheduled Space Service servicing mission (STS-61) in 1993 permitted scientists to correct the problem. The MSFC NBS provided an excellent environment for testing hardware to examine how it would operate in space and for evaluating techniques for space construction and spacecraft servicing.

  6. Surface Buoyancy Fluxes and the Strength of the Subpolar Gyre

    Science.gov (United States)

    Hogg, A. M.; Gayen, B.

    2017-12-01

    Midlatitude ocean gyres have long been considered to be driven by the mechanical wind stress on the ocean's surface (strictly speaking, the potential vorticity input from wind stress curl). However, surface buoyancy forcing (i.e. heating/cooling or freshening/salinification) also modifies the potential vorticity at the surface. Here, we present a simple argument to demonstrate that ocean gyres may (in principle) be driven by surface buoyancy forcing. This argument is derived in two ways: A Direct Numerical Simulation, driven purely by buoyancy forcing, which generates strong nonlinear gyers in the absence of wind stress; and A series of idealised eddy-resolving numerical ocean model simulations, in which wind stress and buoyancy flux are varied independently and together, are used to understand the relative importance of these two types of forcing. In these simulations, basin-scale gyres and western boundary currents with realistic magnitudes, remain even in the absence of mechanical forcing by surface wind stress. These results support the notion that surface buoyancy forcing can reorganise the potential vorticity in the ocean in such a way as to drive basin-scale gyres. The role of buoyancy is stronger in the subpolar gyre than in the subtropical gyre. We infer that surface buoyancy fluxes are likely to play a contributing role in governing the strength, variability and predictability of the North Atlantic subpolar gyre.

  7. Buoyancy flow in fractures intersecting a nuclear waste repository

    International Nuclear Information System (INIS)

    Wang, J.S.Y.; Tsang, C.F.

    1980-07-01

    The thermally induced buoyancy flow in fractured rocks around a nuclear waste repository is of major concern in the evaluation of the regional, long-term impact of nuclear waste disposal in geological formation. In this study, buoyancy flow and the development of convective cells are calculated in vertical fractures passing through or positioned near a repository. Interaction between buoyancy flow and regional hydraulic gradient is studied as a function of time, and the interference of intersecting fractures with each other is also discussed

  8. Homogeneous purely buoyancy driven turbulent flow

    Science.gov (United States)

    Arakeri, Jaywant; Cholemari, Murali; Pawar, Shashikant

    2010-11-01

    An unstable density difference across a long vertical tube open at both ends leads to convection that is axially homogeneous with a linear density gradient. We report results from such tube convection experiments, with driving density caused by salt concentration difference or temperature difference. At high enough Rayleigh numbers (Ra) the convection is turbulent with zero mean flow and zero mean Reynolds shear stresses; thus turbulent production is purely by buoyancy. We observe different regimes of turbulent convection. At very high Ra the Nusselt number scales as the square root of the Rayleigh number, giving the so-called "ultimate regime" of convection predicted for Rayleigh-Benard convection in limit of infinite Ra. Turbulent convection at intermediate Ra, the Nusselt number scales as Ra^0.3. In both regimes, the flux and the Taylor scale Reynolds number are more than order of magnitude larger than those obtained in Rayleigh-Benard convection. Absence of a mean flow makes this an ideal flow to study shear free turbulence near a wall.

  9. Semi-Empirical Models for Buoyancy-Driven Ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2015-01-01

    A literature study is presented on the theories and models dealing with buoyancy-driven ventilation in rooms. The models are categorised into four types according to how the physical process is conceived: column model, fan model, neutral plane model and pressure model. These models are analysed...... and compared with a reference model. Discrepancies and differences are shown, and the deviations are discussed. It is concluded that a reliable buoyancy model based solely on the fundamental flow equations is desirable....

  10. The Competition Between a Localised and Distributed Source of Buoyancy

    Science.gov (United States)

    Partridge, Jamie; Linden, Paul

    2012-11-01

    We propose a new mathematical model to study the competition between localised and distributed sources of buoyancy within a naturally ventilated filling box. The main controlling parameters in this configuration are the buoyancy fluxes of the distributed and local source, specifically their ratio Ψ. The steady state dynamics of the flow are heavily dependent on this parameter. For large Ψ, where the distributed source dominates, we find the space becomes well mixed as expected if driven by an distributed source alone. Conversely, for small Ψ we find the space reaches a stable two layer stratification. This is analogous to the classical case of a purely local source but here the lower layer is buoyant compared to the ambient, due to the constant flux of buoyancy emanating from the distributed source. The ventilation flow rate, buoyancy of the layers and also the location of the interface height, which separates the two layer stratification, are obtainable from the model. To validate the theoretical model, small scale laboratory experiments were carried out. Water was used as the working medium with buoyancy being driven directly by temperature differences. Theoretical results were compared with experimental data and overall good agreement was found. A CASE award project with Arup.

  11. Optimal design and control of buoyancy-driven ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2016-01-01

    Relationships between airflow rates and opening areas of importance for design and control are analysed for buoyancy-driven ventilation in a room with two openings and uniform temperature. The optimal ratio between the inlet and outlet areas is found. The consequences of deviations from the optimum...

  12. Buoyancy disorders in pet axolotls Ambystoma mexicanum: three cases.

    Science.gov (United States)

    Takami, Yoshinori; Une, Yumi

    2018-01-31

    As far as we are aware, there are no previous reports on the pathologic conditions of buoyancy disorders in Ambystoma mexicanum. Herein, we describe various clinical test results, clinical outcomes, and the pathological findings of an experimental pneumonectomy procedure in 3 A. mexicanum exhibiting abnormal buoyancy. The 3 pet A. mexicanum were adults, and their respective ages and body weights were 1, 5, and 6 yr and 48, 55, and 56 g. Two of these cases were confirmed via radiographic examination to have free air within the body cavity, and all 3 cases were found via ultrasonography to have an acoustic shadow within the body cavity and were diagnosed with pneumocoelom. Lung perforations were detected macroscopically in 2 of the cases, and all 3 cases had fibrosis in the caudal ends of the lungs. Removal of the lung lesions eliminated the abnormal buoyancy in all 3 cases. We concluded that air had leaked into the body cavity from the lungs, and we propose that lung lesions are an important cause of buoyancy disorders in A. mexicanum.

  13. Use of an Arduino to Study Buoyancy Force

    Science.gov (United States)

    Espindola, P. R.; Cena, C. R.; Alves, D. C. B.; Bozano, D. F.; Goncalves, A. M. B.

    2018-01-01

    The study of buoyancy becomes very interesting when we measure the apparent weight of the body and the liquid vessel weight. In this paper, we propose an experimental apparatus that measures both the forces mentioned before as a function of the depth that a cylinder is sunk into the water. It is done using two load cells connected to an Arduino.…

  14. EVA Development and Verification Testing at NASA's Neutral Buoyancy Laboratory

    Science.gov (United States)

    Jairala, Juniper C.; Durkin, Robert; Marak, Ralph J.; Sipila, Stepahnie A.; Ney, Zane A.; Parazynski, Scott E.; Thomason, Arthur H.

    2012-01-01

    As an early step in the preparation for future Extravehicular Activities (EVAs), astronauts perform neutral buoyancy testing to develop and verify EVA hardware and operations. Neutral buoyancy demonstrations at NASA Johnson Space Center's Sonny Carter Training Facility to date have primarily evaluated assembly and maintenance tasks associated with several elements of the International Space Station (ISS). With the retirement of the Shuttle, completion of ISS assembly, and introduction of commercial players for human transportation to space, evaluations at the Neutral Buoyancy Laboratory (NBL) will take on a new focus. Test objectives are selected for their criticality, lack of previous testing, or design changes that justify retesting. Assembly tasks investigated are performed using procedures developed by the flight hardware providers and the Mission Operations Directorate (MOD). Orbital Replacement Unit (ORU) maintenance tasks are performed using a more systematic set of procedures, EVA Concept of Operations for the International Space Station (JSC-33408), also developed by the MOD. This paper describes the requirements and process for performing a neutral buoyancy test, including typical hardware and support equipment requirements, personnel and administrative resource requirements, examples of ISS systems and operations that are evaluated, and typical operational objectives that are evaluated.

  15. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced as...

  16. Manipulating Microrobots Using Balanced Magnetic and Buoyancy Forces

    Directory of Open Access Journals (Sweden)

    Lin Feng

    2018-01-01

    Full Text Available We present a novel method for the three-dimensional (3D control of microrobots within a microfluidic chip. The microrobot body contains a hollow space, producing buoyancy that allows it to float in a microfluidic environment. The robot moves in the z direction by balancing magnetic and buoyancy forces. In coordination with the motion of stages in the xy plane, we achieved 3D microrobot control. A microgripper designed to grasp micron-scale objects was attached to the front of the robot, allowing it to hold and deliver micro-objects in three dimensions. The microrobot had four degrees of freedom and generated micronewton-order forces. We demonstrate the microrobot’s utility in an experiment in which it grips a 200 μm particle and delivers it in a 3D space.

  17. SuperLig Ion Exchange Resin Swelling and Buoyancy Study

    International Nuclear Information System (INIS)

    Hassan, N.M.

    2000-01-01

    The objective of this study was to achieve a fundamental understanding of SuperLig resin swelling and shrinking characteristics, which lead to channeling and early breakthrough during loading cycles. The density of salt solution that causes resin floating was also determined to establish a limit for operation. Specific tests performed include (a) pH dependence, (b) ionic strength dependence and (c) buoyancy effect vs. simulant composition

  18. Buoyancy Effects in Turbulent Jet Flames in Crossflow

    Science.gov (United States)

    Boxx, Isaac; Idicheria, Cherian; Clemens, Noel

    2003-11-01

    The aim of this study is to investigate the effects of buoyancy on the structure of turbulent, non-premixed hydrocarbon jet-flames in crossflow (JFICF). This was accomplished using a small jet-in-crossflow facility which can be oriented at a variety of angles with respect to the gravity vector. This facility enables us to alter the relative influence of buoyancy on the JFICF without altering the jet-exit Reynolds number, momentum flux ratio or the geometry of the system. Results are compared to similar, but non-buoyant, JFICF studied in microgravity. Departures of jet-centerline trajectory from the well-known power-law scaling of turbulent JFICF were used to explore the transition from a buoyancy-influenced regime to a momentum dominated one. The primary diagnostic was CCD imaging of soot-luminosity. We present results on ethylene jet flames with jet-exit Reynolds numbers of 1770 to 8000 and momentum flux ratios of 5 to 13.

  19. A continuous and prognostic convection scheme based on buoyancy, PCMT

    Science.gov (United States)

    Guérémy, Jean-François; Piriou, Jean-Marcel

    2016-04-01

    A new and consistent convection scheme (PCMT: Prognostic Condensates Microphysics and Transport), providing a continuous and prognostic treatment of this atmospheric process, is described. The main concept ensuring the consistency of the whole system is the buoyancy, key element of any vertical motion. The buoyancy constitutes the forcing term of the convective vertical velocity, which is then used to define the triggering condition, the mass flux, and the rates of entrainment-detrainment. The buoyancy is also used in its vertically integrated form (CAPE) to determine the closure condition. The continuous treatment of convection, from dry thermals to deep precipitating convection, is achieved with the help of a continuous formulation of the entrainment-detrainment rates (depending on the convective vertical velocity) and of the CAPE relaxation time (depending on the convective over-turning time). The convective tendencies are directly expressed in terms of condensation and transport. Finally, the convective vertical velocity and condensates are fully prognostic, the latter being treated using the same microphysics scheme as for the resolved condensates but considering the convective environment. A Single Column Model (SCM) validation of this scheme is shown, allowing detailed comparisons with observed and explicitly simulated data. Four cases covering the convective spectrum are considered: over ocean, sensitivity to environmental moisture (S. Derbyshire) non precipitating shallow convection to deep precipitating convection, trade wind shallow convection (BOMEX) and strato-cumulus (FIRE), together with an entire continental diurnal cycle of convection (ARM). The emphasis is put on the characteristics of the scheme which enable a continuous treatment of convection. Then, a 3D LAM validation is presented considering an AMMA case with both observations and a CRM simulation using the same initial and lateral conditions as for the parameterized one. Finally, global

  20. Experimental study of buoyancy driven natural ventilation through horizontal openings

    OpenAIRE

    Heiselberg, Per; Li, Zhigang

    2007-01-01

    An experimental study of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. Measurements were made for opening ratios L/D range from 0.027 to 4.455, where L and D are the length and the diameter of the opening, respectively. The bidirectional air flow rate was measured using constant injection tracer gas technique. Smoke visualizations showed that the air flow patterns are highly transient, unstable and complex, and ...

  1. Use of an Arduino to study buoyancy force

    Science.gov (United States)

    Espindola, P. R.; Cena, C. R.; Alves, D. C. B.; Bozano, D. F.; Goncalves, A. M. B.

    2018-05-01

    The study of buoyancy becomes very interesting when we measure the apparent weight of the body and the liquid vessel weight. In this paper, we propose an experimental apparatus that measures both the forces mentioned before as a function of the depth that a cylinder is sunk into the water. It is done using two load cells connected to an Arduino. With this experiment, the student can verify Archimedes’ principle, Newton’s third law, and calculate the density of a liquid. This apparatus can be used in fluid physics laboratories as a substitute for very expensive sensor kits or even to improve too simple approaches, usually employed, but still at low cost.

  2. Modeling the Buoyancy System of a Wave Energy Power Plant

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Nielsen, Kirsten M.

    2009-01-01

    A nonlinear dynamic model of the buoyancy system in a wave energy power plant is presented. The plant ("Wave Dragon") is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the WD, and hydro turbines lead the water to the sea...... producing electrical power. Through air chambers it is possible to control the level of the WD. It is important to control the level in order to maximize the power production in proportion to the wave height, here the amount of overtopping water and the amount of potential energy is conflicting...

  3. Experimental study of buoyancy driven natural ventilation through horizontal openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2007-01-01

    An experimental study of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. Measurements were made for opening ratios L/D range from 0.027 to 4.455, where L and D are the length and the diameter of the opening......, respectively. The bidirectional air flow rate was measured using constant injection tracer gas technique. Smoke visualizations showed that the air flow patterns are highly transient, unstable and complex, and that air flow rates oscillate with time. Correlations between the Froude number Fr and the L/D ratio...

  4. Buoyancy of gas-filled bladders at great depth

    Science.gov (United States)

    Priede, Imants G.

    2018-02-01

    At high hydrostatic pressures exceeding 20 MPa or 200 bar, equivalent to depths exceeding ca.2000 m, the behaviour of gases deviates significantly from the predictions of standard equations such as Boyle's Law, the Ideal Gas Law and Van der Waals equation. The predictions of these equations are compared with experimental data for nitrogen, oxygen and air at 0 °C and 15 °C, at pressures up to 1100 bar (110 MPa) equivalent to full ocean depth of ca. 11000 m. Owing to reduced compressibility of gases at high pressures, gas-filled bladders at full ocean depth have a density of 847 kg m-3 for Oxygen, 622 kg m-3 for Nitrogen and 660 kg m-3 for air providing potentially useful buoyancy comparable with that available from man-made materials. This helps explain why some of the deepest-living fishes at ca. 7000 m depth (700 bar or 70 MPa) have gas-filled swim bladders. A table is provided of the density and buoyancy of oxygen, nitrogen and air at 0 °C and 15 °C from 100 to 1100 bar.

  5. Response of mantle transition zone thickness to plume buoyancy flux

    Science.gov (United States)

    Das Sharma, S.; Ramesh, D. S.; Li, X.; Yuan, X.; Sreenivas, B.; Kind, R.

    2010-01-01

    The debate concerning thermal plumes in the Earth's mantle, their geophysical detection and depth characterization remains contentious. Available geophysical, petrological and geochemical evidence is at variance regarding the very existence of mantle plumes. Utilizing P-to-S converted seismic waves (P receiver functions) from the 410 and 660 km discontinuities, we investigate disposition of these boundaries beneath a number of prominent hotspot regions. The thickness of the mantle transition zone (MTZ), measured as P660s-P410s differential times (tMTZ), is determined. Our analyses suggest that the MTZ thickness beneath some hotspots correlates with the plume strength. The relationship between tMTZ, in response to the thermal perturbation, and the strength of plumes, as buoyancy flux B, follows a power law. This B-tMTZ behavior provides unprecedented insights into the relation of buoyancy flux and excess temperature at 410-660 km depth below hotspots. We find that the strongest hotspots, which are located in the Pacific, are indeed plumes originating at the MTZ or deeper. According to the detected power law, even the strongest plumes may not shrink the transition zone by significantly more than ~40 km (corresponding to a maximum of 300-400° excess temperature).

  6. Characteristics of Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Li, Zhigang

    through horizontal openings. Two cases of full-scale measurements of buoyancy driven natural ventilation through horizontal openings are performed: one horizontal opening and one horizontal opening combined with one vertical opening. For the case of one horizontal opening, the measurements are made....... Computational fluid dynamics (CFD) are used to study these two air flow cases. The air flow rate and air flow pattern are predicted and compared with the full-scale measurements. The measurement data are used to compare two CFD models: standard k- ε model and large eddy simulation (LES) model. The cases...... transient, unstable and complex, and the air flow rates oscillate with time. Correlations between the Froude number Fr and the opening ratio L/D are obtained, which is reasonable agreement with Epstein's formula derived from brine-water measurements, but the obtained Fr values show considerable deviations...

  7. Buoyancy-driven mixing of fluids in a confined geometry

    International Nuclear Information System (INIS)

    Hallez, Y.

    2007-12-01

    The present work based on Direct Numerical Simulations is devoted to the study of mixing between two miscible fluids of different densities. The movement of these fluids is induced by buoyancy. Three geometries are considered: a cylindrical tube, a square channel and a plane two-dimensional flow. For cylindrical tubes, the results of numerical simulations fully confirm previous experimental findings by Seon et al., especially regarding the existence of three different flow regimes, depending on the tilt angle. The comparison of the various geometries shows that tridimensional flows in tubes or channels are similar, whereas the two-dimensional model fails to give reliable information about real 3D flows, either from a quantitative point of view or for a phenomenological understanding. A peculiar attention is put on a joint analysis of the concentration and vorticity fields and allows us to explain several subtle aspects of the mixing dynamics. (author)

  8. Buoyancy differences among two deepwater ciscoes from the Great Lakes and their putative ancestor

    Science.gov (United States)

    Krause, A.E.; Eshenroder, R.L.; Begnoche, L.J.

    2002-01-01

    We analyzed buoyancy in two deepwater ciscoes, Coregonus hoyi and C. kiyi, and in C. artedi, their putative ancestor, and also analyzed how variations in fish weight, water content, and lipid content affected buoyancy. Buoyancy was significantly different among the three species (p < 0.0001). Estimates of percent buoyancy (neutral buoyancy = 0.0%) were: kiyi, 3.8%; hoyi, 4.7%; and artedi, 5.7%. Buoyancy did not change with fish weight alone (p = 0.38). Fish weight was negatively related to water content for all three species (p = 0.037). Lipid content was not significantly different between hoyi and kiyi, but artedi had significantly fewer lipids than hoyi and kiyi (p < 0.10). When artedi was removed from the analysis, fish weight and lipids accounted for 48% of the variation in buoyancy (p = 0.003), fatter hoyi were less dense than leaner hoyi, but fatter and leaner kiyi were no different in density. Our findings provide additional evidence that buoyancy regulation was a speciating mechanism in deepwater ciscoes and that kiyi is more specialized than hoyi for diel-vertical migration in deep water.

  9. Research and development at the Marshall Space Flight Center Neutral Buoyancy Simulator

    Science.gov (United States)

    Kulpa, Vygantas P.

    1987-01-01

    The Neutral Buoyancy Simulator (NBS), a facility designed to imitate zero-gravity conditions, was used to test the Experimental Assembly of Structures in Extravehicular Activity (EASE) and the Assembly Concept for Construction of Erectable Space Structures (ACCESS). Neutral Buoyancy Simulator applications and operations; early space structure research; development of the EASE/ACCESS experiments; and improvement of NBS simulation are summarized.

  10. 40 CFR 1065.690 - Buoyancy correction for PM sample media.

    Science.gov (United States)

    2010-07-01

    ... mass, use a sample media density of 920 kg/m3. (3) For PTFE membrane (film) media with an integral... media. 1065.690 Section 1065.690 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Buoyancy correction for PM sample media. (a) General. Correct PM sample media for their buoyancy in air if...

  11. Analysis of Buoyancy Module Auxiliary Installation Technology Based on Numerical Simulation

    Science.gov (United States)

    Xu, Songsen; Jiao, Chunshuo; Ning, Meng; Dong, Sheng

    2018-04-01

    To reduce the requirement for lifting capacity and decrease the hoist cable force during the descending and laying process of a subsea production system (SPS), a buoyancy module auxiliary installation technology was proposed by loading buoyancy modules on the SPS to reduce the lifting weight. Two models are established, namely, the SPS lowering-down model and the buoyancy module floating-up model. The main study results are the following: 1) When the buoyancy module enters the water under wave condition, the amplitude of tension fluctuation is twice that when SPS enters water; 2) Under current condition, the displacement of SPS becomes three times larger because of the existence of the buoyancy module; 3) After being released, the velocity of the buoyancy module increases to a large speed rapidly and then reaches a balancing speed gradually. The buoyancy module floats up at a balancing speed and rushes out from the water at a pop-up distance; 4) In deep water, the floating-up velocity of the buoyancy module is related to its mass density and shape, and it is not related to water depth; 5) A drag parachute can reduce floating-up velocity and pop-up distance effectively. Good agreement was found between the simulation and experiment results.

  12. Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals.

    Science.gov (United States)

    Sato, Katsufumi; Aoki, Kagari; Watanabe, Yuuki Y; Miller, Patrick J O

    2013-01-01

    Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.

  13. Large eddy simulation of a buoyancy-aided flow in a non-uniform channel – Buoyancy effects on large flow structures

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); He, S., E-mail: s.he@sheffield.ac.uk [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2017-02-15

    Highlights: • Buoyancy may greatly redistribute the flow in a non-uniform channel. • Flow structures in the narrow gap are greatly changed when buoyancy is strong. • Large flow structures exist in wider gap, which is enhanced when heat is strong. • Buoyancy reduces mixing factor caused by large flow structures in narrow gap. - Abstract: It has been a long time since the ‘abnormal’ turbulent intensity distribution and high inter-sub-channel mixing rates were observed in the vicinity of the narrow gaps formed by the fuel rods in nuclear reactors. The extraordinary flow behaviour was first described as periodic flow structures by Hooper and Rehme (1984). Since then, the existences of large flow structures were demonstrated by many researchers in various non-uniform flow channels. It has been proved by many authors that the Strouhal number of the flow structure in the isothermal flow is dependent on the size of the narrow gap, not the Reynolds number once it is sufficiently large. This paper reports a numerical investigation on the effect of buoyancy on the large flow structures. A buoyancy-aided flow in a tightly-packed rod-bundle-like channel is modelled using large eddy simulation (LES) together with the Boussinesq approximation. The behaviour of the large flow structures in the gaps of the flow passage are studied using instantaneous flow fields, spectrum analysis and correlation analysis. It is found that the non-uniform buoyancy force in the cross section of the flow channel may greatly redistribute the velocity field once the overall buoyancy force is sufficiently strong, and consequently modify the large flow structures. The temporal and axial spatial scales of the large flow structures are influenced by buoyancy in a way similar to that turbulence is influenced. These scales reduce when the flow is laminarised, but start increasing in the turbulence regeneration region. The spanwise scale of the flow structures in the narrow gap remains more or

  14. Matching Subsequences in Trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2009-01-01

    Given two rooted, labeled trees P and T the tree path subsequence problem is to determine which paths in P are subsequences of which paths in T. Here a path begins at the root and ends at a leaf. In this paper we propose this problem as a useful query primitive for XML data, and provide new...

  15. Assessment of RANS and LES Turbulence Modeling for Buoyancy-Aided/Opposed Forced and Mixed Convection

    Science.gov (United States)

    Clifford, Corey; Kimber, Mark

    2017-11-01

    Over the last 30 years, an industry-wide shift within the nuclear community has led to increased utilization of computational fluid dynamics (CFD) to supplement nuclear reactor safety analyses. One such area that is of particular interest to the nuclear community, specifically to those performing loss-of-flow accident (LOFA) analyses for next-generation very-high temperature reactors (VHTR), is the capacity of current computational models to predict heat transfer across a wide range of buoyancy conditions. In the present investigation, a critical evaluation of Reynolds-averaged Navier-Stokes (RANS) and large-eddy simulation (LES) turbulence modeling techniques is conducted based on CFD validation data collected from the Rotatable Buoyancy Tunnel (RoBuT) at Utah State University. Four different experimental flow conditions are investigated: (1) buoyancy-aided forced convection; (2) buoyancy-opposed forced convection; (3) buoyancy-aided mixed convection; (4) buoyancy-opposed mixed convection. Overall, good agreement is found for both forced convection-dominated scenarios, but an overly-diffusive prediction of the normal Reynolds stress is observed for the RANS-based turbulence models. Low-Reynolds number RANS models perform adequately for mixed convection, while higher-order RANS approaches underestimate the influence of buoyancy on the production of turbulence.

  16. Inherent work suit buoyancy distribution: effects on lifejacket self-righting performance.

    Science.gov (United States)

    Barwood, Martin J; Long, Geoffrey M; Lunt, Heather; Tipton, Michael J

    2014-09-01

    Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman's test to the 0.05 alpha level. All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario.

  17. Natural ventilation of buildings: opposing wind and buoyancy

    Science.gov (United States)

    Linden, Paul; Hunt, Gary

    1998-11-01

    The use of natural ventilation in buildings is an attractive way to reduce energy usage thereby reducing costs and CO2 emissions. Generally, it is necessary to remove excess heat from a building and the designer can use the buoyancy forces associated with the above ambient temperatures within the building to drive a flow - 'stack' ventilation. The most efficient mode is displacement ventilation where warm air accumulates near the top of the building and flows out through upper level vents and cooler air flows in at lower levels. Ventilation will also be driven between these lower and upper openings by the wind. We report on laboratory modeling and theory which investigates the effects of an opposing wind on stack ventilation driven by a constant source of heat within a space under displacement ventilation. We show that there is a critical wind speed, expressed in dimensionless terms as a critical Froude number, above which displacement ventilation is replaced by (less efficient) mixing ventilation with reversed flow. Below this critical speed, displacement ventilation, in which the interior has a two-layer stratification, is maintained. The criterion for the change in ventilation mode is derived from general considerations of mixing efficiencies in stratified flows. We conclude that even when wind effects might appear to be dominant, the inhibition of mixing by the stable stratification within the space ensures that stack ventilation can operate over a wide range of apparently adverse conditions.

  18. Numerical modeling of buoyancy-driven turbulent flows in enclosures

    International Nuclear Information System (INIS)

    Hsieh, K.J.; Lien, F.S.

    2004-01-01

    Modeling turbulent natural convection in enclosures with differentially heated vertical walls is numerically challenging, in particular, when low-Reynolds-number (low-Re) models are adopted. When the turbulence level in the core region of cavity is low, most low-Re models, particular those showing good performance for bypass transitional flows, tend to relaminarize the flow and, as a consequence, significantly underpredict the near-wall turbulence intensities and boundary-layer thickness. Another challenge associated with low-turbulence buoyancy-driven flows in enclosures is its inherent unsteadiness, which can pose convergence problems when a steady Reynolds-averaged Navier-Stokes (RANS) equation is solved. In the present study, an unsteady RANS approach in conjunction with the low-Re k-ε model of Lien and Leschziner [Int. J. Comput. Fluid Dyn. 12 (1999) 1] is initially adopted and the predicted flow field is found effectively relaminarized. To overcome this difficulty, likely caused by the low-Re functions in the ε-equation, the two-layer approach is attempted, in which ε is prescribed algebraically using the one-equation k-l model of Wolfshtein [Int. J. Heat Mass Transfer 12 (1969) 301]. The two-layer approach combined with a quadratic stress-strain relation gives overall the best performance in terms of mean velocities, temperature and turbulence quantities

  19. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, 2000-present, Buoyancy Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Buoyancy Flux data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  20. Buoyancy package for self-contained acoustic doppler current profiler mooring

    Digital Repository Service at National Institute of Oceanography (India)

    Venkatesan, R.; Krishnakumar, V.

    A buoyancy package for self-contained Acoustic Doppler Current Profiler(SC-ADCP 1200 RD instruments USA) was designed and fabricated indigenously, for subsurface mooring in coastal waters. The system design is discussed. The design to keep SC...

  1. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, 2000-present, Buoyancy Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Buoyancy Flux data from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/ ), RAMA (Indian Ocean,...

  2. Numerical and Experimental Study on Negative Buoyance Induced Vortices in N-Butane Jet Flames

    KAUST Repository

    Xiong, Yuan; Cha, Min; Chung, Suk-Ho

    2015-01-01

    Near nozzle flow field in flickering n-butane diffusion jet flames was investigated with a special focus on transient flow patterns of negative buoyance induced vortices. The flow structures were obtained through Mie scattering imaging with seed

  3. Buoyancy Regulation and the Energetics of Diving in Dolphins Seals, Sea Lions and Sea Otters

    National Research Council Canada - National Science Library

    Costa, Daniel

    1998-01-01

    We examined swim speed and ascent descent rates in sea lions and elephant seals in order to make comparisons in their diving strategies and how these may be effected by different strategies of buoyancy regulation...

  4. Buoyancy increase and drag-reduction through a simple superhydrophobic coating

    OpenAIRE

    Hwang, G. B.; Patir, A.; Page, K.; Lu, Y.; Allan, E.; Parkin, I. P.

    2017-01-01

    A superhydrophobic paint was fabricated using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES), TiO2 nanoparticles and ethanol. The paint has potential for aquatic application of a superhydrophobic coating as it induces increased buoyancy and drag reduction. Buoyance testing showed that the reduction of surface energy by superhydrophobic coating made it feasible that glass, a high density material, was supported by the surface tension of water. In a miniature boat sailing test, it was shown...

  5. THE INFLUENCE OF BUOYANCY ON FLOW AND POLLUTANT DISPERSION IN STREET CANYONS

    OpenAIRE

    Buccolieri, Riccardo; Pulvirenti, Beatrice; Di Sabatino, Silvana; Britter, Rex

    2008-01-01

    Abstract: In this paper, the effect of buoyancy on flow and pollutant dispersion within street canyons is studied by means of computational fluid dynamics simulations. We consider a neutral boundary layer approaching a 3D street canyon assuming a wind direction perpendicular to the street canyon. The Boussinesq hypothesis for incompressible fluids is chosen for modelling buoyancy. We distinguish three cases: leeward, ground and windward wall heating. Thermal effects on both the flow ...

  6. Influence of Buoyancy Control Performance on Power Production by the Wave Dragon Nissum Bredning Prototype

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Tedd, James; Friis-Madsen, E.

    2007-01-01

    This paper reports on the real sea performance of the buoyancy control system of Wave Dragon, a floating wave energy converter using the overtopping principle. The device operates with the full independent control system which has been tested during three years of operation. The impact of the buo...... of the buoyancy control system performance on the power production is noted. This provides motivation and a target for improved control algorithms....

  7. Mixing driven by transient buoyancy flows. I. Kinematics

    Science.gov (United States)

    Duval, W. M. B.; Zhong, H.; Batur, C.

    2018-05-01

    Mixing of two miscible liquids juxtaposed inside a cavity initially separated by a divider, whose buoyancy-driven motion is initiated via impulsive perturbation of divider motion that can generate the Richtmyer-Meshkov instability, is investigated experimentally. The measured Lagrangian history of interface motion that contains the continuum mechanics of mixing shows self-similar nearly Gaussian length stretch distribution for a wide range of control parameters encompassing an approximate Hele-Shaw cell to a three-dimensional cavity. Because of the initial configuration of the interface which is parallel to the gravitational field, we show that at critical initial potential energy mixing occurs through the stretching of the interface, which shows frontogenesis, and folding, owing to an overturning motion that results in unstable density stratification and produces an ideal condition for the growth of the single wavelength Rayleigh-Taylor instability. The initial perturbation of the interface and flow field generates the Kelvin-Helmholtz instability and causes kinks at the interface, which grow into deep fingers during overturning motion and unfold into local whorl structures that merge and self-organize into the Rayleigh-Taylor morphology (RTM) structure. For a range of parametric space that yields two-dimensional flows, the unfolding of the instability through a supercritical bifurcation yields an asymmetric pairwise structure exhibiting smooth RTM that transitions to RTM fronts with fractal structures that contain small length scales for increasing Peclet numbers. The late stage of the RTM structure unfolds into an internal breakwave that breaks down through wall and internal collision and sets up the condition for self-induced sloshing that decays exponentially as the two fluids become stably stratified with a diffusive region indicating local molecular diffusion.

  8. BUOYANCY INSTABILITIES IN A WEAKLY COLLISIONAL INTRACLUSTER MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Matthew W.; Stone, James M. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States); Bogdanovic, Tamara; Reynolds, Christopher S., E-mail: kunz@astro.princeton.edu, E-mail: jstone@astro.princeton.edu, E-mail: tamarab@astro.umd.edu, E-mail: chris@astro.umd.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2012-08-01

    The intracluster medium (ICM) of galaxy clusters is a weakly collisional plasma in which the transport of heat and momentum occurs primarily along magnetic-field lines. Anisotropic heat conduction allows convective instabilities to be driven by temperature gradients of either sign: the magnetothermal instability (MTI) in the outskirts of clusters and the heat-flux buoyancy-driven instability (HBI) in their cooling cores. We employ the Athena magnetohydrodynamic code to investigate the nonlinear evolution of these instabilities, self-consistently including the effects of anisotropic viscosity (i.e., Braginskii pressure anisotropy), anisotropic conduction, and radiative cooling. We find that, in all but the innermost regions of cool-core clusters, anisotropic viscosity significantly impairs the ability of the HBI to reorient magnetic-field lines orthogonal to the temperature gradient. Thus, while radio-mode feedback appears necessary in the central few Multiplication-Sign 10 kpc, heat conduction may be capable of offsetting radiative losses throughout most of a cool core over a significant fraction of the Hubble time. Magnetically aligned cold filaments are then able to form by local thermal instability. Viscous dissipation during cold filament formation produces accompanying hot filaments, which can be searched for in deep Chandra observations of cool-core clusters. In the case of MTI, anisotropic viscosity leads to a nonlinear state with a folded magnetic field structure in which field-line curvature and field strength are anti-correlated. These results demonstrate that, if the HBI and MTI are relevant for shaping the properties of the ICM, one must self-consistently include anisotropic viscosity in order to obtain even qualitatively correct results.

  9. Gravitaxis of Euglena gracilis depends only partially on passive buoyancy

    Science.gov (United States)

    Richter, Peter R.; Schuster, Martin; Lebert, Michael; Streb, Christine; Häder, Donat-Peter

    In darkness, the unicellular freshwater flagellate Euglena gracilis shows a pronounced negative gravitactic behavior, and the cells swim actively upward in the water column. Up to now it was unclear whether this behavior is based on a passive (physical) alignment mechanism (e.g., buoyancy due to a fore-aft asymmetry of the cell body) or on an active physiological mechanism. A sounding rocket experiment was performed in which the effect of sub-1g-accelerations (0.05, 0.08, 0.12, and 0.2g) on untreated living cells and immobilized (fixation with liquid nitrogen) cells was observed. By means of computerized image analysis the angles of the cells long axis with respect to the acceleration vector were analyzed in order to calculate and compare the reorientation kinetics of the immobilized cells versus that of the controls. In both groups, the reorientation kinetics depended on the dose, but the reorientation of the living cells was about five times faster than that of the immobilized cells. This indicates that in young cells gravitaxis can be explained by a physical mechanism only to a small extend. In older cultures, in which the cells often have a drop shaped cell body, the physical reorientation is considerably faster, and a more pronounced influence of passive alignment caused by fore/aft asymmetry (drag-gravity model) can not be excluded. In addition to these results, Euglena gracilis cells seem to respond very sensitively to small accelerations when they are applied after a longer microgravity period. The data indicate that gravitactic orientation occurred at an acceleration as low as 0.05g.

  10. Buoyancy-activated cell sorting using targeted biotinylated albumin microbubbles.

    Directory of Open Access Journals (Sweden)

    Yu-Ren Liou

    Full Text Available Cell analysis often requires the isolation of certain cell types. Various isolation methods have been applied to cell sorting, including fluorescence-activated cell sorting and magnetic-activated cell sorting. However, these conventional approaches involve exerting mechanical forces on the cells, thus risking cell damage. In this study we applied a novel isolation method called buoyancy-activated cell sorting, which involves using biotinylated albumin microbubbles (biotin-MBs conjugated with antibodies (i.e., targeted biotin-MBs. Albumin MBs are widely used as contrast agents in ultrasound imaging due to their good biocompatibility and stability. For conjugating antibodies, biotin is conjugated onto the albumin MB shell via covalent bonds and the biotinylated antibodies are conjugated using an avidin-biotin system. The albumin microbubbles had a mean diameter of 2 μm with a polydispersity index of 0.16. For cell separation, the MDA-MB-231 cells are incubated with the targeted biotin-MBs conjugated with anti-CD44 for 10 min, centrifuged at 10 g for 1 min, and then allowed 1 hour at 4 °C for separation. The results indicate that targeted biotin-MBs conjugated with anti-CD44 antibodies can be used to separate MDA-MB-231 breast cancer cells; more than 90% of the cells were collected in the MB layer when the ratio of the MBs to cells was higher than 70:1. Furthermore, we found that the separating efficiency was higher for targeted biotin-MBs than for targeted avidin-incorporated albumin MBs (avidin-MBs, which is the most common way to make targeted albumin MBs. We also demonstrated that the recovery rate of targeted biotin-MBs was up to 88% and the sorting purity was higher than 84% for a a heterogenous cell population containing MDA-MB-231 cells (CD44(+ and MDA-MB-453 cells (CD44-, which are classified as basal-like breast cancer cells and luminal breast cancer cells, respectively. Knowing that the CD44(+ is a commonly used cancer

  11. Effects of Buoyancy on Laminar and Turbulent Premixed V-Flame

    Science.gov (United States)

    Cheng, Robert K.; Bedat, Benoit

    1997-01-01

    Turbulent combustion occurs naturally in almost all combustion systems and involves complex dynamic coupling of chemical and fluid mechanical processes. It is considered as one of the most challenging combustion research problems today. Though buoyancy has little effect on power generating systems operating under high pressures (e.g., IC engines and turbines), flames in atmospheric burners and the operation of small to medium furnaces and boilers are profoundly affected by buoyancy. Changes in burner orientation impacts on their blow-off, flash-back and extinction limits, and their range of operation, burning rate, heat transfer, and emissions. Theoretically, buoyancy is often neglected in turbulent combustion models. Yet the modeling results are routinely compared with experiments of open laboratory flames that are obviously affected by buoyancy. This inconsistency is an obstacle to reconciling experiments and theories. Consequently, a fundamental understanding of the coupling between turbulent flames and buoyancy is significant to both turbulent combustion science and applications. The overall effect of buoyancy relates to the dynamic interaction between the flame and its surrounding, i.e., the so-called elliptical problem. The overall flame shape, its flowfield, stability, and mean and local burning rates are dictated by both upstream and downstream boundary conditions. In steady propagating premixed flames, buoyancy affects the products region downstream of the flame zone. These effects are manifested upstream through the mean and fluctuating pressure fields to influence flame stretch and flame wrinkling. Intuitively, the effects buoyancy should diminish with increasing flow momentum. This is the justification for excluding buoyancy in turbulent combustion models that treats high Reynolds number flows. The objectives of our experimental research program is to elucidate flame-buoyancy coupling processes in laminar and turbulent premixed flames, and to

  12. Ceramic Spheres—A Novel Solution to Deep Sea Buoyancy Modules

    Science.gov (United States)

    Jiang, Bo; Blugan, Gurdial; Sturzenegger, Philip N.; Gonzenbach, Urs T.; Misson, Michael; Thornberry, John; Stenerud, Runar; Cartlidge, David; Kuebler, Jakob

    2016-01-01

    Ceramic-based hollow spheres are considered a great driving force for many applications such as offshore buoyancy modules due to their large diameter to wall thickness ratio and uniform wall thickness geometric features. We have developed such thin-walled hollow spheres made of alumina using slip casting and sintering processes. A diameter as large as 50 mm with a wall thickness of 0.5–1.0 mm has been successfully achieved in these spheres. Their material and structural properties were examined by a series of characterization tools. Particularly, the feasibility of these spheres was investigated with respect to its application for deep sea (>3000 m) buoyancy modules. These spheres, sintered at 1600 °C and with 1.0 mm of wall thickness, have achieved buoyancy of more than 54%. As the sphere’s wall thickness was reduced (e.g., 0.5 mm), their buoyancy reached 72%. The mechanical performance of such spheres has shown a hydrostatic failure pressure above 150 MPa, corresponding to a rating depth below sea level of 5000 m considering a safety factor of 3. The developed alumina-based ceramic spheres are feasible for low cost and scaled-up production and show great potential at depths greater than those achievable by the current deep-sea buoyancy module technologies. PMID:28773651

  13. Service Innovation In Academic Libraries

    DEFF Research Database (Denmark)

    Scupola, Ada; Nicolajsen, Hanne Westh

    2010-01-01

    Purpose – The purpose of this article is to investigate whether management and employees in academic libraries involve users in library service innovations and what these user roles are. Design/methodology/approach – The article first reviews the literature focusing on innovation, new product...... development, new service development and library science with specific focus on users and management. Subsequently the research uses a case study approach to investigate management and customer involvement in a Danish academic library. Findings – Results from the case study show that academic libraries...... in academic library service innovations on the basis of an in-depth case study of a Danish academic library....

  14. Flows and Stratification of an Enclosure Containing Both Localised and Vertically Distributed Sources of Buoyancy

    Science.gov (United States)

    Partridge, Jamie; Linden, Paul

    2013-11-01

    We examine the flows and stratification established in a naturally ventilated enclosure containing both a localised and vertically distributed source of buoyancy. The enclosure is ventilated through upper and lower openings which connect the space to an external ambient. Small scale laboratory experiments were carried out with water as the working medium and buoyancy being driven directly by temperature differences. A point source plume gave localised heating while the distributed source was driven by a controllable heater mat located in the side wall of the enclosure. The transient temperatures, as well as steady state temperature profiles, were recorded and are reported here. The temperature profiles inside the enclosure were found to be dependent on the effective opening area A*, a combination of the upper and lower openings, and the ratio of buoyancy fluxes from the distributed and localised source Ψ =Bw/Bp . Industrial CASE award with ARUP.

  15. Buoyancy increase and drag-reduction through a simple superhydrophobic coating.

    Science.gov (United States)

    Hwang, Gi Byoung; Patir, Adnan; Page, Kristopher; Lu, Yao; Allan, Elaine; Parkin, Ivan P

    2017-06-08

    A superhydrophobic paint was fabricated using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES), TiO 2 nanoparticles and ethanol. The paint has potential for aquatic application of a superhydrophobic coating as it induces increased buoyancy and drag reduction. Buoyance testing showed that the reduction of surface energy by superhydrophobic coating made it feasible that glass, a high density material, was supported by the surface tension of water. In a miniature boat sailing test, it was shown that the low energy surface treatment decreased the adhesion of water molecules to the surface of the boat resulting in a reduction of the drag force. Additionally, a robust superhydrophobic surface was fabricated through layer-by-layer coating using adhesive double side tape and the paint, and after a 100 cm abrasion test with sand paper, the surface still retained its water repellency, enhanced buoyancy and drag reduction.

  16. Feedback mechanisms of shallow convective clouds in a warmer climate as demonstrated by changes in buoyancy

    Science.gov (United States)

    Dagan, G.; Koren, I.; Altaratz, O.; Feingold, G.

    2018-05-01

    Cloud feedbacks could influence significantly the overall response of the climate system to global warming. Here we study the response of warm convective clouds to a uniform temperature change under constant relative humidity (RH) conditions. We show that an increase in temperature drives competing effects at the cloud scale: a reduction in the thermal buoyancy term and an increase in the humidity buoyancy term. Both effects are driven by the increased contrast in the water vapor content between the cloud and its environment, under warming with constant RH. The increase in the moisture content contrast between the cloud and its environment enhances the evaporation at the cloud margins, increases the entrainment, and acts to cool the cloud. Hence, there is a reduction in the thermal buoyancy term, despite the fact that theoretically this term should increase.

  17. Academic Hospitality

    Science.gov (United States)

    Phipps, Alison; Barnett, Ronald

    2007-01-01

    Academic hospitality is a feature of academic life. It takes many forms. It takes material form in the hosting of academics giving papers. It takes epistemological form in the welcome of new ideas. It takes linguistic form in the translation of academic work into other languages, and it takes touristic form through the welcome and generosity with…

  18. Release of radon contaminants from Yucca Mountain: The role of buoyancy driven flow

    International Nuclear Information System (INIS)

    Sullivan, T.M.; Pescatore, C.

    1994-02-01

    The potential for the repository heat source to promote buoyancy driven flow and thereby cause release of radon gas out of Yucca Mountain has been examined through a critical review of the theoretical and experimental studies of this process. The review indicates that steady-state buoyancy enhanced release of natural radon and other contaminant gases should not be a major concern at Yucca Mountain. Barometric pumping and wind pumping are identified as two processes that will have a potentially greater effect on surface releases of gases

  19. Buoyancy effects in vertical rectangular duct with coplanar magnetic field and single sided heat load

    Science.gov (United States)

    Kostichev, P. I.; Poddubnyi, I. I.; Razuvanov, N. G.

    2017-11-01

    In some DEMO blanket designs liquid metal flows in vertical ducts of rectangular cross-section between ceramic breeder units providing their cooling. Heat exchange in these conditions is governed by the influence of magnetic field (coplanar) and by buoyancy effects that depend on the flow orientation to the gravity vector (downward and upward flow). Magnetohydrodynamic and heat transfer of liquid metal in vertical rectangular ducts is not well researched. Experimental study of buoyancy effects in rectangular duct with coplanar magnetic field for one-sided heat load and downward and upward flowsis presented in this paper. The detail research with has been done on mercury MHD close loop with using of the probe technique allow to discover several advantageous and disadvantageous effects. The intensive impact of buoyancy force has been observed in a few regime of downward flow which has been laminarized by magnetic field. Due to the development in the flow of the secondary large-scale vortices heat transfer improved and the temperature fluctuations of the abnormally high intensity have been fixed. On the contrary, in the upward flow the buoyancy force stabilized the flow which lead to decreasing of the turbulence heat transfer ratio and, consequently, deterioration of heat transfer.

  20. An experimental and analytical study of a buoyancy driven cooling system for a particle accelerator

    International Nuclear Information System (INIS)

    Campbell, B.; Ranganathan, R.

    1993-05-01

    A buoyancy driven closed-loop cooling system that transports the heat generated in a particle accelerator to the ambient has been evaluated both through experiments performed earlier and analysis techniques developed elsewhere. Excellent comparisons between measurements and calculations have been obtained. The model illustrates the feasibility (from a heat transfer viewpoint) of such a cooling system for a particle accelerator

  1. An experimental and analytical study of a buoyancy driven cooling system for a particle accelerator

    International Nuclear Information System (INIS)

    Campbell, B.; Ranganathan, R.

    1993-01-01

    A buoyancy driven closed-loop cooling system that transports the heat generated in a particle accelerator to the ambient has been evaluated both through experiments performed earlier and analysis techniques developed elsewhere. Excellent comparisons between measurements and calculations have been obtained. The model illustrates the feasibility (from a heat transfer viewpoint) of such a cooling system for a particle accelerator

  2. Core-annular flow through a horizontal pipe : Hydrodynamic counterbalancing of buoyancy force on core

    NARCIS (Netherlands)

    Ooms, G.; Vuik, C.; Poesio, P.

    2007-01-01

    A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference

  3. Processes governing transient responses of the deep ocean buoyancy budget to a doubling of CO2

    Science.gov (United States)

    Palter, J. B.; Griffies, S. M.; Hunter Samuels, B. L.; Galbraith, E. D.; Gnanadesikan, A.

    2012-12-01

    Recent observational analyses suggest there is a temporal trend and high-frequency variability in deep ocean buoyancy in the last twenty years, a phenomenon reproduced even in low-mixing models. Here we use an earth system model (GFDL's ESM2M) to evaluate physical processes that influence buoyancy (and thus steric sea level) budget of the deep ocean in quasi-steady state and under a doubling of CO2. A new suite of model diagnostics allows us to quantitatively assess every process that influences the buoyancy budget and its temporal evolution, revealing surprising dynamics governing both the equilibrium budget and its transient response to climate change. The results suggest that the temporal evolution of the deep ocean contribution to sea level rise is due to a diversity of processes at high latitudes, whose net effect is then advected in the Eulerian mean flow to mid and low latitudes. In the Southern Ocean, a slowdown in convection and spin up of the residual mean advection are approximately equal players in the deep steric sea level rise. In the North Atlantic, the region of greatest deep steric sea level variability in our simulations, a decrease in mixing of cold, dense waters from the marginal seas and a reduction in open ocean convection causes an accumulation of buoyancy in the deep subpolar gyre, which is then advected equatorward.

  4. On the influence of buoyancy and suction/injection In Heat and Mass ...

    African Journals Online (AJOL)

    In this paper, we examined the influence of buoyancy and suction/injection in the problem of unsteady convection with chemical reaction and radiative heat transfer past a flat porous plate moving through a binary mixture in an optically thin environment is presented. The dimensionless governing equations for this ...

  5. Buoyancy frequency profiles and internal semidiurnal tide turning depths in the oceans

    NARCIS (Netherlands)

    King, B.; Stone, M.; Zhang, H.P.; Gerkema, T.; Marder, M.; Scott, R.B.; Swinney, H.L.

    2012-01-01

    We examine the possible existence of internal gravity wave "turning depths," depths below which the local buoyancy frequency N(z) becomes smaller than the wave frequency. At a turning depth, incident gravity waves reflect rather than reaching the ocean bottom as is generally assumed. Here we

  6. Experimental aspects of buoyancy correction in measuring reliable highpressure excess adsorption isotherms using the gravimetric method.

    Science.gov (United States)

    Nguyen, Huong Giang T; Horn, Jarod C; Thommes, Matthias; van Zee, Roger D; Espinal, Laura

    2017-12-01

    Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO 2 and supercritical N 2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

  7. Numerical investigation of the onset of centrifugal buoyancy in a rotating cavity

    Science.gov (United States)

    Pitz, Diogo B.; Marxen, Olaf; Chew, John

    2016-11-01

    Buoyancy-induced flows in a differentially heated rotating annulus present a multitude of dynamics when control parameters such as rotation rate, temperature difference and Prandtl number are varied. Whilst most of the work in this area has been motivated by applications involving geophysics, the problem of buoyancy-induced convection in rotating systems is also relevant in industrial applications such as the flow between rotating disks of turbomachinery internal air systems, in which buoyancy plays a major role and poses a challenge to accurately predict temperature distributions and heat transfer rates. In such applications the rotational speeds involved are very large, so that the centrifugal accelerations induced are much higher than gravity. In this work we perform direct numerical simulations and linear stability analysis of flow induced by centrifugal buoyancy in a sealed rotating annulus of finite gap with flat end-walls, using a canonical setup representative of an internal air system rotating cavity. The analysis focuses on the behaviour of small-amplitude disturbances added to the base flow, and how those affect the onset of Rossby waves and, ultimately, the transition to a fully turbulent state where convection columns no longer have a well-defined structure. Diogo B. Pitz acknowledges the financial support from the Capes foundation through the Science without Borders program.

  8. Investigating Students' Ideas About Buoyancy and the Influence of Haptic Feedback

    Science.gov (United States)

    Minogue, James; Borland, David

    2016-04-01

    While haptics (simulated touch) represents a potential breakthrough technology for science teaching and learning, there is relatively little research into its differential impact in the context of teaching and learning. This paper describes the testing of a haptically enhanced simulation (HES) for learning about buoyancy. Despite a lifetime of everyday experiences, a scientifically sound explanation of buoyancy remains difficult to construct for many. It requires the integration of domain-specific knowledge regarding density, fluid, force, gravity, mass, weight, and buoyancy. Prior studies suggest that novices often focus on only one dimension of the sinking and floating phenomenon. Our HES was designed to promote the integration of the subconcepts of density and buoyant forces and stresses the relationship between the object itself and the surrounding fluid. The study employed a randomized pretest-posttest control group research design and a suite of measures including an open-ended prompt and objective content questions to provide insights into the influence of haptic feedback on undergraduate students' thinking about buoyancy. A convenience sample (n = 40) was drawn from a university's population of undergraduate elementary education majors. Two groups were formed from haptic feedback (n = 22) and no haptic feedback (n = 18). Through content analysis, discernible differences were seen in the posttest explanations sinking and floating across treatment groups. Learners that experienced the haptic feedback made more frequent use of "haptically grounded" terms (e.g., mass, gravity, buoyant force, pushing), leading us to begin to build a local theory of language-mediated haptic cognition.

  9. Annual and seasonal mean buoyancy fluxes for the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, T.G.

    . The fluxes of heat and freshwater across the air-sea interface, and hence the surface buoyancy flux, show strong spatial and temporal variability. The Bay of Bengal and eastern equatorial Indian Ocean are characterized by a net freshwater gain due to heavy...

  10. Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei.

    Directory of Open Access Journals (Sweden)

    Itsumi Nakamura

    Full Text Available We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200-300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200-300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes, indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats.

  11. Unexpected Positive Buoyancy in Deep Sea Sharks, Hexanchus griseus, and a Echinorhinus cookei.

    Science.gov (United States)

    Nakamura, Itsumi; Meyer, Carl G; Sato, Katsufumi

    2015-01-01

    We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural habitat, but this has never been confirmed. To empirically determine the buoyancy status of two species of deep-sea sharks (bluntnose sixgill sharks, Hexanchus griseus, and a prickly shark, Echinorhinus cookei) in their natural habitat, we used accelerometer-magnetometer data loggers to measure their swimming performance. Both species of deep-sea sharks showed similar diel vertical migrations: they swam at depths of 200-300 m at night and deeper than 500 m during the day. Ambient water temperature was around 15°C at 200-300 m but below 7°C at depths greater than 500 m. During vertical movements, all deep-sea sharks showed higher swimming efforts during descent than ascent to maintain a given swimming speed, and were able to glide uphill for extended periods (several minutes), indicating that these deep-sea sharks are in fact positively buoyant in their natural habitats. This positive buoyancy may adaptive for stealthy hunting (i.e. upward gliding to surprise prey from underneath) or may facilitate evening upward migrations when muscle temperatures are coolest, and swimming most sluggish, after spending the day in deep, cold water. Positive buoyancy could potentially be widespread in fish conducting daily vertical migration in deep-sea habitats.

  12. Tail thrust of bluefish Pomatomus saltatrix at different buoyancies, speeds, and swimming angles.

    Science.gov (United States)

    Ogilvy, C S; DuBois, A B

    1982-06-01

    1. The tail thrust of bluefish Pomatomus saltatrix was measured using a body accelerometer at different water speeds, buoyancies, and angles of water flow to determine the contribution of tail thrust in overcoming parasitic drag, induced drag, and weight directed along the track. The lengths and weights of the fish averaged 0.52 m and 1.50 kg respectively. 2. The tail thrust overcoming parasitic drag in Newtons, as measured during neutral buoyancy, was: 0.51 x speed + 0.15, with a standard error of estimate of 0.09 N. 3. When buoyancy was altered by the introduction or removal of air from a balloon implanted in the swim bladder, the tail thrust was altered by an amount of the same order as the value calculated for the induced drag of the pectoral fins. 4. The component of weight directed backward along the track was the weight in water multiplied by the sine of the angle of the swimming tunnel relative to horizontal. When this force was added to the calculated induced drag and tail thrust measured at neutral buoyancy, the rearward force equal to the tail thrust, at 45 ml negative buoyancy, 0.5 m s-1, and 15 degrees head up, was 0.12 N due to weight + 0.05 N due to induced drag + 0.40 N due to parasitic drag = 0.57 N total rearward force. 5. The conditions required for gliding were not achieved in our bluefish because the drag exceeded the component of the weight in water directed forward along the track at speeds above the stalling speed of the pectoral fins.

  13. Academics respond

    DEFF Research Database (Denmark)

    Hazel, Spencer

    2015-01-01

    Contribution to the article "Academics respond: Brexit would weaken UK university research and funding", Guardian Witness, The Guardian, UK......Contribution to the article "Academics respond: Brexit would weaken UK university research and funding", Guardian Witness, The Guardian, UK...

  14. Academic writing

    Science.gov (United States)

    Eremina, Svetlana V.

    2003-10-01

    The series of workshops on academic writing have been developed by academic writing instructors from Language Teaching Centre, Central European University and presented at the Samara Academic Writing Workshops in November 2001. This paper presents only the part dealing with strucutre of an argumentative essay.

  15. The Academic Publishing Industry

    DEFF Research Database (Denmark)

    Nell, Phillip Christopher; Wenzel, Tim Ole; Schmidt, Florian

    2014-01-01

    The case starts with introducing the outstanding profitability of academic journal publishers such as Elsevier and then dives into describing the research process from an idea to conducting research and to publishing the results in academic journals. Subsequently, demand and supply for scientific...... journals and papers are discussed including drivers and involved parties. Furthermore, the case describes competition between suppliers, customers, and publishers. In sum, the case study features a rich description of the industry’s many unusual attributes which allows for discussing the benefits...

  16. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans.

    Science.gov (United States)

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature. From specific gravity measurements of marine fish eggs salinity appears to be the only determinant of the buoyancy indicating that the thermal expansions of the fish egg and the ambient seawater are equal. We analyze the mechanisms behind thermal expansion in fish eggs in order to determine to what extent it can be justified to neglect the effects of temperature on buoyancy. Our results confirm the earlier assumptions that salinity is the basic determinant on buoyancy in marine fish eggs that, in turn, influence the vertical distributions and, consequently, the dispersal of fish eggs from the spawning areas. Fish populations have adapted accordingly by producing egg specific gravities that tune the egg buoyancy to create specific vertical distributions for each local population. A wide variety of buoyancy adaptations are found among fish populations. The ambient physical conditions at the spawning sites form a basic constraint for adaptation. In coastal regions where salinity increases with depth, and where the major fraction of the fish stocks spawns, pelagic and mesopelagic egg distributions dominate. However, in the larger part of worlds' oceans salinity decreases with depth resulting in different egg distributions. Here, the principles of vertical distributions of fish eggs in the world oceans are presented in an overarching framework presenting the basic differences between regions, mainly coastal, where salinity increases with depth and the major part of the world oceans where salinity decreases with depth. We show that under these latter conditions, steady-state vertical distribution of mesopelagic fish eggs cannot exist as it does in most coastal regions. In fact, a critical spawning depth must exist where spawning below this depth threshold results in eggs sinking out of the water column and become lost for

  17. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans

    Science.gov (United States)

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    Buoyancy acting on plankton, i.e. the difference in specific gravity between plankton and the ambient water, is a function of salinity and temperature. From specific gravity measurements of marine fish eggs salinity appears to be the only determinant of the buoyancy indicating that the thermal expansions of the fish egg and the ambient seawater are equal. We analyze the mechanisms behind thermal expansion in fish eggs in order to determine to what extent it can be justified to neglect the effects of temperature on buoyancy. Our results confirm the earlier assumptions that salinity is the basic determinant on buoyancy in marine fish eggs that, in turn, influence the vertical distributions and, consequently, the dispersal of fish eggs from the spawning areas. Fish populations have adapted accordingly by producing egg specific gravities that tune the egg buoyancy to create specific vertical distributions for each local population. A wide variety of buoyancy adaptations are found among fish populations. The ambient physical conditions at the spawning sites form a basic constraint for adaptation. In coastal regions where salinity increases with depth, and where the major fraction of the fish stocks spawns, pelagic and mesopelagic egg distributions dominate. However, in the larger part of worlds’ oceans salinity decreases with depth resulting in different egg distributions. Here, the principles of vertical distributions of fish eggs in the world oceans are presented in an overarching framework presenting the basic differences between regions, mainly coastal, where salinity increases with depth and the major part of the world oceans where salinity decreases with depth. We show that under these latter conditions, steady-state vertical distribution of mesopelagic fish eggs cannot exist as it does in most coastal regions. In fact, a critical spawning depth must exist where spawning below this depth threshold results in eggs sinking out of the water column and become lost

  18. Studies of heat transfer having relevance to nuclear reactor containment cooling by buoyancy-driven air flow

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, J. D.; Li, J.; Wang, J. [The Univ., of Manchester, Manchester (United Kingdom)

    2003-07-01

    Two separate effects experiments concerned with buoyancy-influenced convective heat transfer in vertical passages which have relevance to the problem of nuclear reactor containment cooling by means of buoyancy-driven airflow are described. A feature of each is that local values of heat transfer coefficient are determined on surfaces maintained at uniform temperature. Experimental results are presented which highlight the need for buoyancy-induced impairment of turbulent convective heat transfer to be accounted for in the design of such passive cooling systems. A strategy is presented for predicting the heat removal by combined convective and radiative heat transfer from a full scale nuclear reactor containment shell using such experimental results.

  19. Practicing for space underwater: inventing neutral buoyancy training, 1963-1968.

    Science.gov (United States)

    Neufeld, Michael J; Charles, John B

    2015-01-01

    Neutral buoyancy's value was far from obvious when human spaceflight began in 1961. Starting in 1964, Environmental Research Associates, a tiny company in the suburbs of Baltimore, developed the key innovations in an obscure research project funded by NASA's Langley Research Center. The new Houston center dismissed it until a mid-1966 EVA crisis, after which it rapidly took over. In parallel, NASA Marshall Space Flight Center developed many of the same techniques, as did many large aerospace corporations, yet the long-run technological impact of corporate activity was near zero. Because ERA and Marshall's pioneering activities led to the two long-running NASA training centers at Houston and Huntsville, those two organizations deserve primary credit for the construction of the neutral buoyancy technological system. Published by Elsevier Ltd.

  20. Buoyancy Limitation of Filamentous Cyanobacteria under Prolonged Pressure due to the Gas Vesicles Collapse.

    Science.gov (United States)

    Abeynayaka, Helayaye Damitha Lakmali; Asaeda, Takashi; Kaneko, Yasuko

    2017-08-01

    Freshwater cyanobacterium Pseudanabaena galeata were cultured in chambers under artificially generated pressures, which correspond to the hydrostatic pressures at deep water. Variations occurred in gas vesicles volume, and buoyancy state of cells under those conditions were analyzed at different time intervals (5 min, 1 day, and 5 days). Variations in gas vesicles morphology of cells were observed by transmission electron microscopy images. Settling velocity (Vs) of cells which governs the buoyancy was observed with the aid of a modified optical microscope. Moreover, effects of the prolonged pressure on cell ballast composition (protein and polysaccharides) were examined. Elevated pressure conditions reduced the cell ballast and caused a complete disappearance of gas vesicles in Pseudanabaena galeata cells. Hence cyanobacteria cells were not able to float within the study period. Observations and findings of the study indicate the potential application of hydrostatic pressure, which naturally occurred in hypolimnion of lakes, to inhibit the re-suspension of cyanobacteria cells.

  1. The effects of buoyancy on turbulent nonpremixed jet flames in crossflow

    Science.gov (United States)

    Boxx, Isaac G.

    An experimental research study was conducted to investigate what effect buoyancy had on the mean and instantaneous flow-field characteristics of turbulent jet-flames in crossflow (JFICF). The study used an experimental technique wherein a series of normal-gravity, hydrogen-diluted propane JFICF were compared with otherwise identical ones in low-gravity. Experiments were conducted at the University of Texas Drop Tower Facility, a new microgravity science laboratory built for this study at the University of Texas at Austin. Two different diagnostic techniques were employed, high frame-rate digital cinematographic imaging and planar laser Mie scattering (PLMS). The flame-luminosity imaging revealed significant elongation and distortion of the large-scale luminous structure of the JFICF. This was seen to affect the flametip oscillation and burnout characteristics. Mean and root-mean-square (RMS) images of flame-luminosity were computed from the flame-luminosity image sequences. These were used to compare visible flame-shapes, flame chord-lengths and jet centerline-trajectories of the normal- and low-gravity flames. In all cases the jet-centerline penetration and mean luminous flame-width were seen to increase with decreasing buoyancy. The jet-centerline trajectories for the normal-gravity flames were seen to behave differently to those of the low-gravity flames. This difference led to the conclusion that the jet transitions from a momentum-dominated forced convection limit to a buoyancy-influenced regime when it reaches xiC ≈ 3, where xiC is the Becker and Yamazaki (1978) buoyancy parameter based on local flame chord-length. The mean luminous flame-lengths showed little sensitivity to buoyancy or momentum flux ratio. Consistent with the flame-luminosity imaging experiments, comparison of the instantaneous PLMS flow-visualization images revealed substantial buoyancy-induced elongation and distortion of the large-scale shear-layer vortices in the flow. This effect

  2. Tropical cloud buoyancy is the same in a world with or without ice

    Science.gov (United States)

    Seeley, Jacob T.; Romps, David M.

    2016-04-01

    When convective clouds grow above the melting line, where temperatures fall below 0°C, condensed water begins to freeze and water vapor is deposited. These processes release the latent heat of fusion, which warms cloud air, and many previous studies have suggested that this heating from fusion increases cloud buoyancy in the upper troposphere. Here we use numerical simulations of radiative-convective equilibrium with and without ice processes to argue that tropical cloud buoyancy is not systematically higher in a world with fusion than in a world without it. This insensitivity results from the fact that the environmental temperature profile encountered by developing tropical clouds is itself determined by convection. We also offer a simple explanation for the large reservoir of convective available potential energy in the tropical upper troposphere that does not invoke ice.

  3. Numerical and Experimental Study on Negative Buoyance Induced Vortices in N-Butane Jet Flames

    KAUST Repository

    Xiong, Yuan

    2015-07-26

    Near nozzle flow field in flickering n-butane diffusion jet flames was investigated with a special focus on transient flow patterns of negative buoyance induced vortices. The flow structures were obtained through Mie scattering imaging with seed particles in a fuel stream using continuous-wave (CW) Argon-ion laser. Velocity fields were also quantified with particle mage velocimetry (PIV) system having kHz repetition rate. The results showed that the dynamic motion of negative buoyance induced vortices near the nozzle exit was coupled strongly with a flame flickering instability. Typically during the flame flickering, the negative buoyant vortices oscillated at the flickering frequency. The vortices were distorted by the flickering motion and exhibited complicated transient vortical patterns, such as tilting and stretching. Numerical simulations were also implemented based on an open source C++ package, LaminarSMOKE, for further validations.

  4. Neutral buoyancy testing of architectural and environmental concepts of space vehicle design

    Science.gov (United States)

    Lenda, J. A.; Rosener, A. A.; Stephenson, M. L.

    1972-01-01

    Design guidelines are presented that are applicable to providing habitability areas and furniture elements for extended periods in a zero gravity environment. This was accomplished by: (1) analyzing the existing habitability crew area requirements, mobility and restraint aids, cross-cultural design, and establishing a man model for zero gravity; (2) designing specific furniture elements, chair and table, and volumes for a stateroom, office, bathroom, galley, and wardroom; and (3) neutral buoyancy testing and evaluation of these areas.

  5. Experimental Study of Wind-Opposed Buoyancy-Driven Natural Ventilation

    OpenAIRE

    Andersen, A.; Bjerre, M.; Chen, Z. D.; Heiselberg, Per; Li, Y.

    2000-01-01

    Natural ventilation driven by natural forces, i.e. wind and thermal buoyancy, is an environmentally friendly system for buildings and has been increasingly used around the world in recent years to mitigate the impact on the global environment due to the significant energy consumption by heating, ventilation and air-conditioning (HV AC). There is a need for the understanding and development of theories and tools related to the design, operation and control of natural ventilation systems.

  6. Buoyancy frequency profiles and internal semidiurnal tide turning depths in the oceans

    OpenAIRE

    King, B.; Stone, M.; Zhang, H.P.; Gerkema, T.; Marder, M.; Scott, R.B.; Swinney, H.L.

    2012-01-01

    We examine the possible existence of internal gravity wave "turning depths," depths below which the local buoyancy frequency N(z) becomes smaller than the wave frequency. At a turning depth, incident gravity waves reflect rather than reaching the ocean bottom as is generally assumed. Here we consider internal gravity waves at the lunar semidiurnal (M-2) tidal frequency, omega(M2). Profiles of N-2(z) (the quantity in the equations of motion) are computed using conductivity, temperature, and de...

  7. Statistical Change Detection for Diagnosis of Buoyancy Element Defects on Moored Floating Vessels

    DEFF Research Database (Denmark)

    Blanke, Mogens; Fang, Shaoji; Galeazzi, Roberto

    2012-01-01

    . After residual generation, statistical change detection scheme is derived from mathematical models supported by experimental data. To experimentally verify loss of an underwater buoyancy element, an underwater line breaker is designed to create realistic replication of abrupt faults. The paper analyses...... the properties of residuals and suggests a dedicated GLRT change detector based on a vector residual. Special attention is paid to threshold selection for non ideal (non-IID) test statistics....

  8. Experimental Study of Wind-Opposed Buoyancy-Driven Natural Ventilation

    DEFF Research Database (Denmark)

    Andersen, A.; Bjerre, M.; Chen, Z. D.

    Natural ventilation driven by natural forces, i.e. wind and thermal buoyancy, is an environmentally friendly system for buildings and has been increasingly used around the world in recent years to mitigate the impact on the global environment due to the significant energy consumption by heating......, ventilation and air-conditioning (HV AC). There is a need for the understanding and development of theories and tools related to the design, operation and control of natural ventilation systems....

  9. The effect of buoyancy on flow and heat transfer in curved pipes

    OpenAIRE

    Mochizuki, Munekazu; Ishigaki, Hiroshi; 望月 宗和; 石垣 博

    1994-01-01

    Fully developed laminar flow in a heated horizontal curved pipe is studied numerically. The thermal boundary conditions at the wall are uniform wall heat flux axially and uniform wall temperature peripherally. Flow and heat transfer are governed by Dean number, Prandtl number and buoyancy number. Detailed prediction of the friction factor, average heat transfer rate, velocity profile, temperature profile and secondary-flow streamlines are given.

  10. Influences of buoyancy and thermal boundary conditions on heat transfer with naturally-induced flow

    International Nuclear Information System (INIS)

    Jackson, J.D.; Li, J.

    2002-01-01

    A fundamental study is reported of heat transfer from a vertical heated tube to air which is induced naturally upwards through it by the action of buoyancy. Measurements of local heat transfer coefficient were made using a specially designed computer-controlled power supply and measurement system for conditions of uniform wall temperature and uniform wall heat flux. The effectiveness of heat transfer proved to be much lower than for conditions of forced convection. It was found that the results could be correlated satisfactorily when presented in terms of dimensionless parameters similar to those used for free convection heat transfer from vertical surfaces provided that the heat transfer coefficients were evaluated using local fluid bulk temperature calculated utilising the measured values of flow rate induced through the system. Additional experiments were performed' with pumped flow. These covered the entire mixed convection region. It was found that the data for naturally-induced flow mapped onto the pumped flow data when presented in terms of Nusselt number ratio (mixed to forced) and buoyancy parameter. Computational simulations of the experiments were performed using an advanced computer code which incorporated a buoyancy-influenced, variable property, developing wall shear flow formulation and a low Reynolds number k-ε turbulence model. These reproduced observed behaviour quite well. (author)

  11. Buoyancy-driven mean flow in a long channel with a hydraulically constrained exit condition

    Science.gov (United States)

    Grimm, Th.; Maxworthy, T.

    1999-11-01

    Convection plays a major role in a variety of natural hydrodynamic systems. Those in which convection drives exchange flows through a lateral contraction and/or over a sill form a special class with typical examples being the Red and Mediterranean Seas, the Persian Gulf, and the fjords that indent many coastlines. The present work focuses on the spatial distribution and scaling of the density difference between the inflowing and outflowing fluid layers. Using a long water-filled channel, fitted with buoyancy sources at its upper surface, experiments were conducted to investigate the influence of the geometry of the strait and the channel as well as the magnitude of the buoyancy flux. Two different scaling laws, one by Phillips (1966), and one by Maxworthy (1994, 1997) were compared with the experimental results. It has been shown that a scaling law for which g[prime prime or minute] = kB02/3x/h4/3 best describes the distribution of the observed density difference along the channel, where B0 is the buoyancy flux, x the distance from the closed end of the channel, h its height at the open end (sill) and k a constant that depends on the details of the channel geometry and flow conditions. This result holds for the experimental results and appears to be valid for a number of natural systems as well.

  12. Prominence Bubbles and Plumes: Thermo-magnetic Buoyancy in Coronal Cavity Systems

    Science.gov (United States)

    Berger, Thomas; Hurlburt, N.

    2009-05-01

    The Hinode/Solar Optical Telescope continues to produce high spatial and temporal resolution images of solar prominences in both the Ca II 396.8 nm H-line and the H-alpha 656.3 nm line. Time series of these images show that many quiescent prominences produce large scale (50 Mm) dark "bubbles" that "inflate" into, and sometimes burst through, the prominence material. In addition, small-scale (2--5 Mm) dark plumes are seen rising into many quiescent prominences. We show typical examples of both phenomena and argue that they originate from the same mechanism: concentrated and heated magnetic flux that rises due to thermal and magnetic buoyancy to equilibrium heights in the prominence/coronal-cavity system. More generally, these bubbles and upflows offer a source of both magnetic flux and mass to the overlying coronal cavity, supporting B.C. Low's theory of CME initiation via steadily increasing magnetic buoyancy breaking through the overlying helmut streamer tension forces. Quiescent prominences are thus seen as the lowermost parts of the larger coronal cavity system, revealing through thermal effects both the cooled downflowing "drainage" from the cavity and the heated upflowing magnetic "plasmoids" supplying the cavity. We compare SOT movies to new 3D compressible MHD simulations that reproduce the dark turbulent plume dynamics to establish the magnetic and thermal character of these buoyancy-driven flows into the corona.

  13. Two-phase turbulent mixing and buoyancy drift in rod bundles

    International Nuclear Information System (INIS)

    Carlucci, L.N.; Hammouda, N.; Rowe, D.S.

    2004-01-01

    This paper describes the development of generalized relationships for single- and two-phase inter subchannel turbulent mixing in vertical and horizontal flows, and lateral buoyancy drift in horizontal flows. The relationships for turbulent mixing, together with a recommended one for void drift, have been implemented in a subchannel thermal hydraulics code, and assessed using a range of data on enthalpy migration in vertical steam-water lows under BWR and PWR diabatic conditions. The intent of this assessment as to optimize these relationships to give the best agreement with the enthalpy migration data for vertical flows. The optimized turbulent mixing relationships were then used as a basis to benchmark a proposed buoyancy rift model to give the best predictions of void and enthalpy migration data n horizontal flows typical of PHWR CANDU reactor operation under normal and off-normal conditions. Overall, the optimized turbulent mixing and buoyancy drift relationships have been found to predict the available data quite well, nd generally better and more consistently than currently used models. This is expected to result in more accurate calculations of subchannel distributions of phasic flows, and hence, in improved predictions of critical heat flux (CHF)

  14. Analysis of Understanding the Concept of Buoyancy in the Context of its Transfer from Pre-school Teachers to Children

    Directory of Open Access Journals (Sweden)

    Petra Furlan

    2014-03-01

    Full Text Available Kindergarten curricula (Bahovec et al. 1999, 37 cover different areas of education that are sensibly interconnected and integrated. Science is one of the areas that represent child’s first learning about the surrounding world and the first introduction to nature. Science education is a very suitable approach of introducing children into basic research work, since in nature objects and phenomena are more concrete, and hence the children are instinctively attracted. Therefore, science education could act as a starting point for all other areas of education. Teaching science comprises several difficulties, which are mainly connected with the way how contents are introduced to children. This is often a great challenge and great responsibility for pre-school teachers, because the scientific content needs to be explained in an appropriate way taking into consideration the child's age, the use of correct terminology, and at the same time avoiding inadequate generalization and over-simplification. Buoyancy is a natural phenomenon that is experienced by every child, but which, on the other hand, is quite difficult to explain. With the present study we wished to assess the knowledge considering buoyancy of the part-time students within the Pre-school Teaching educational programme at the Faculty of Education of the University of Primorska, which is performed on different locations throughout Slovenia. These students already teach in the kindergartens and should be well acquainted with buoyancy from previously passed physics courses at the Faculty of Education. We examined how they explained the buoyancy to children in kindergartens, and whether the knowledge about buoyancy is affected by their working experience or the location of their study. The results show that the students’ knowledge about buoyancy is insufficient and incomplete. In addition, many misconceptions about buoyancy are transmitted to the children in the process of teaching

  15. Buoyancy under control: underwater locomotor performance in a deep diving seabird suggests respiratory strategies for reducing foraging effort.

    Directory of Open Access Journals (Sweden)

    Timothée R Cook

    Full Text Available BACKGROUND: Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag and report locomotor adjustments to the change of buoyancy with depth. METHODOLOGY/PRINCIPAL FINDINGS: Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with. CONCLUSIONS/SIGNIFICANCE: Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants--as in other families of diving seabirds--of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control.

  16. Academic dishonsty

    African Journals Online (AJOL)

    User

    This study attempted to investigate students' self reported academic dishonesty in Ethiopian ... university programs can play a key role in ... serious problem in establishing academic ... and Rocha 2006); Asian-Pacific, ... and self-adjustment mediates the ..... In my suggestion, it is better that ..... Comparative and International.

  17. Heart Rate Responses to Unaided Orion Side Hatch Egress in the Neutral Buoyancy Laboratory

    Science.gov (United States)

    English, Kirk L.; Hwang Emma Y.; Ryder, Jeffrey W.; Kelly, Cody; Walker, Thomas; Ploutz-Snyder, Lori L.

    2016-01-01

    NASA is developing the Orion capsule as a vehicle for transporting crewmembers to and from the International Space Station (ISS) and for future human space exploration missions. Orion and other commercial vehicles are designed to splash down in the ocean where nominally support personnel will assist crewmembers in egressing the vehicle. However, off-nominal scenarios will require crewmembers to egress the vehicle unaided, deploy survival equipment, and ingress a life raft. PURPOSE: To determine the heart rate (HR) responses to unaided Orion side hatch egress and raft ingress as a part of the NASA Crew Survival Engineering Team's evaluation of the PORT Orion mockup in the Neutral Buoyancy Laboratory (NBL). METHODS: Nineteen test subjects, including four astronauts (N=19, 14 males/5 females, 38.6+/-8.4 y, 174.4+/-9.6 cm, 75.7+/-13.1 kg), completed a graded maximal test on a cycle ergometer to determine VO2peak and HRpeak and were divided into five crews of four members each; one subject served on two crews. Each crew was required to deploy a life raft, egress the Orion vehicle from the side hatch, and ingress the life raft with two 8 kg emergency packs per crew. Each crew performed this activity one to three times; a total of ten full egresses were completed. Subjects wore a suit that was similar in form, mass, and function to the Modified Advanced Crew Escape Suit (MACES) including helmet, gloves, boots, supplemental O2 bottles, and a CO2-inflated life preserver (approx.18 kg); subjects began each trial seated supine in the PORT Orion mockup with seat belts and mockup O2 and communication connections and ended each trial with all four crewmembers inside the life raft. RESULTS: VO2peak was 40.8+/-6.8 mL/kg/min (3.1+/-0.7 L/min); HRpeak was 181+/-10 bpm. Total egress time across trials was 5.0+/-1.6 min (range: 2.8-8.0 min); all subjects were able to successfully complete all trials. Average maximum HR at activity start, at the hatch opening, in the water, and in the

  18. Subsequence Automata with Default Transitions

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Skjoldjensen, Frederik Rye

    2016-01-01

    of states and transitions) of the subsequence automaton is O(nσ) and that this bound is asymptotically optimal. In this paper, we consider subsequence automata with default transitions, that is, special transitions to be taken only if none of the regular transitions match the current character, and which do...... not consume the current character. We show that with default transitions, much smaller subsequence automata are possible, and provide a full trade-off between the size of the automaton and the delay, i.e., the maximum number of consecutive default transitions followed before consuming a character......(nσ) and delay O(1), thus matching the bound for the standard subsequence automaton construction. The key component of our result is a novel hierarchical automata construction of independent interest....

  19. Subsequence automata with default transitions

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Skjoldjensen, Frederik Rye

    2017-01-01

    of states and transitions) of the subsequence automaton is O(nσ) and that this bound is asymptotically optimal. In this paper, we consider subsequence automata with default transitions, that is, special transitions to be taken only if none of the regular transitions match the current character, and which do...... not consume the current character. We show that with default transitions, much smaller subsequence automata are possible, and provide a full trade-off between the size of the automaton and the delay, i.e., the maximum number of consecutive default transitions followed before consuming a character......(1), thus matching the bound for the standard subsequence automaton construction. Finally, we generalize the result to multiple strings. The key component of our result is a novel hierarchical automata construction of independent interest....

  20. A sharp interface immersed boundary method for vortex-induced vibration in the presence of thermal buoyancy

    Science.gov (United States)

    Garg, Hemanshul; Soti, Atul K.; Bhardwaj, Rajneesh

    2018-02-01

    We report the development of an in-house fluid-structure interaction solver and its application to vortex-induced vibration (VIV) of an elastically mounted cylinder in the presence of thermal buoyancy. The flow solver utilizes a sharp interface immersed boundary method, and in the present work, we extend it to account for the thermal buoyancy using Boussinesq approximation and couple it with a spring-mass system of the VIV. The one-way coupling utilizes an explicit time integration scheme and is computationally efficient. We present benchmark code verifications of the solver for natural convection, mixed convection, and VIV. In addition, we verify a coupled VIV-thermal buoyancy problem at a Reynolds number, Re = 150. We numerically demonstrate the onset of the VIV in the presence of the thermal buoyancy for an insulated cylinder at low Re. The buoyancy is induced by two parallel plates, kept in the direction of flow and symmetrically placed around the cylinder. The plates are maintained at the hot and cold temperature to the same degree relative to the ambient. In the absence of the thermal buoyancy (i.e., the plates are at ambient temperature), the VIV does not occur for Re ≤ 20 due to stable shear layers. By contrast, the thermal buoyancy induces flow instability and the vortex shedding helps us to achieve the VIV at Re ≤ 20, lower than the critical value of Re (≈21.7), reported in the literature, for a self-sustained VIV in the absence of the thermal buoyancy. The present simulations show that the lowest Re to achieve VIV in the presence of the thermal buoyancy is around Re ≈ 3, at Richardson number, Ri = 1. We examine the effect of the reduced velocity (UR), mass ratio (m), Prandtl number (Pr), Richardson number (Ri) on the displacement of the cylinder, lift coefficient, oscillation frequency, the phase difference between displacement and lift force, and wake structures. We obtain a significantly larger vibration amplitude of the cylinder over a wide

  1. On buoyancy-driven natural ventilation of a room with a heated floor

    Science.gov (United States)

    Gladstone, Charlotte; Woods, Andrew W.

    2001-08-01

    The natural ventilation of a room, both with a heated floor and connected to a cold exterior through two openings, is investigated by combining quantitative models with analogue laboratory experiments. The heated floor generates an areal source of buoyancy while the openings allow displacement ventilation to operate. When combined, these produce a steady state in which the air in the room is well-mixed, and the heat provided by the floor equals the heat lost by displacement. We develop a quantitative model describing this process, in which the advective heat transfer through the openings is balanced with the heat flux supplied at the floor. This model is successfully tested with observations from small-scale analogue laboratory experiments. We compare our results with the steady-state flow associated with a point source of buoyancy: for a given applied heat flux, an areal source produces heated air of lower temperature but a greater volume flux of air circulates through the room. We generalize the model to account for the effects of (i) a cooled roof as well as a heated floor, and (ii) an external wind or temperature gradient. In the former case, the direction of the flow through the openings depends on the temperature of the exterior air relative to an averaged roof and floor temperature. In the latter case, the flow is either buoyancy dominated or wind dominated depending on the strength of the pressure associated with the wind. Furthermore, there is an intermediate multiple-solution regime in which either flow regime may develop.

  2. academic libraries

    African Journals Online (AJOL)

    Information Impact: Journal of Information and Knowledge Management

    Information Impact: Journal of Information and Knowledge Management ... Key words: academic libraries, open access, research, researchers, technology ... European commission (2012) reports that affordable and easy access to the results ...

  3. Academic Publications

    OpenAIRE

    Francisco H C Felix

    2017-01-01

    Alternative modes of academic publication. What it is: Page for the dissemination of academic papers in alternative formats. Aimed at the diffusion of the idea of open publication, or open access publication, a branch of open science, a multidisciplinary movement that seeks to modify the paradigm of knowledge production that centralizes it and prevents its spreading. Historically, Western tradition has become firmly rooted in the free dissemination of knowledge among peers. However, the c...

  4. A Review of Some Recent Studies on Buoyancy Driven Flows in an Urban Environment

    OpenAIRE

    Bodhisatta Hajra

    2014-01-01

    This paper reviews some recent studies (after 2000) pertaining to buoyancy driven flows in nature and thier use in reducing air pollution levels in a city (city ventilation). Natural convection flows occur due to the heating and cooling of various urban surfaces (e.g., mountain slopes), leading to upslope and downslope flows. Such flows can have a significant effect on city ventilation which has been the subject of study in the recent times due to increased pollution levels in a city. A major...

  5. The effects of buoyancy on shear-induced melt bands in a compacting porous medium

    Science.gov (United States)

    Butler, S. L.

    2009-03-01

    It has recently been shown [Holtzman, B., Groebner, N., Zimmerman, M., Ginsberg, S., Kohlstedt, D., 2003. Stress-driven melt segregation in partially molten rocks. Geochem. Geophys. Geosyst. 4, Art. No. 8607; Holtzman, B.K., Kohlstedt, D.L., 2007. Stress-driven melt segregation and strain partitioning in partially molten rocks: effects of stress and strain. J. Petrol. 48, 2379-2406] that when partially molten rock is subjected to simple shear, bands of high and low porosity are formed at a particular angle to the direction of instantaneous maximum extension. These have been modeled numerically and it has been speculated that high porosity bands may form an interconnected network with a bulk, effective permeability that is enhanced in a direction parallel to the bands. As a result, the bands may act to focus mantle melt towards the axis of mid-ocean ridges [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679]. In this contribution, we examine the combined effects of buoyancy and matrix shear on a deforming porous layer. The linear theory of Spiegelman [Spiegelman, M., 1993. Flow in deformable porous media. Part 1. Simple analysis. J. Fluid Mech. 247, 17-38; Spiegelman, M., 2003. Linear analysis of melt band formation by simple shear. Geochem. Geophys. Geosyst. 4, doi:10.1029/2002GC000499, Article 8615] and Katz et al. [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679] is generalized to include both the effects of buoyancy and matrix shear on a deformable porous layer with strain-rate dependent rheology. The predictions of linear theory are compared with the early time evolution of our 2D numerical model and they are found to be in excellent agreement. For conditions similar to the upper mantle, buoyancy forces can be similar to or much greater than matrix shear-induced forces. The

  6. Academic Marketing

    Directory of Open Access Journals (Sweden)

    Ecaterina Daniela ZECA

    2017-06-01

    Full Text Available Academic Marketing is an investment in a future dominated by The Forth Industrial Revolution and Globalization and not an expense. This aspect will basically alter our way to teach and to learn. In its dimensions, arguably changes will be like anything we has seen before. We try to assess how will be all unfold but, anyway, academic field response at this challenge should be integrated and comprehensive, involving all stakeholders both public and private sectors, because these changes herald upheaval of whole organizations. The educational service is a special one, delivered today but with effects in the future, the future of the individual, the future of generation, the future of nations. The educational service policy adapted to the requirements of time, brings to the front the opportunity of academic marketing. To analyze demand in a professional way, to measure trends and correlated university programs with the forecast demand for jobs, it is the subject. In the case of academic education, we are talking also about cost, distribution and promotion policies, but being a special service we also discuss about ethic boundaries. This work is an open chapter focusing studies on academic megamarketing, the work keeping up with the pace of change, students enrolment mobility, overtakes job market, and an imposed win-win-win formula, applied for students, local community and academic field.

  7. The Influence of Early Protein Energy Malnutrition on Subsequent Behavior and Intellectual Performance.

    Science.gov (United States)

    Gupta, Sarita

    1990-01-01

    Protein-energy malnutrition in early childhood, as seen in many developing countries, influences subsequent behavior and intellectual performance. These impairments are associated with further reduction in fine motor skills and academic performance. (Author)

  8. Large eddy simulation of pollutant gas dispersion with buoyancy ejected from building into an urban street canyon.

    Science.gov (United States)

    Hu, L H; Xu, Y; Zhu, W; Wu, L; Tang, F; Lu, K H

    2011-09-15

    The dispersion of buoyancy driven smoke soot and carbon monoxide (CO) gas, which was ejected out from side building into an urban street canyon with aspect ratio of 1 was investigated by large eddy simulation (LES) under a perpendicular wind flow. Strong buoyancy effect, which has not been revealed before, on such pollution dispersion in the street canyon was studied. The buoyancy release rate was 5 MW. The wind speed concerned ranged from 1 to 7.5m/s. The characteristics of flow pattern, distribution of smoke soot and temperature, CO concentration were revealed by the LES simulation. Dimensionless Froude number (Fr) was firstly introduced here to characterize the pollutant dispersion with buoyancy effect counteracting the wind. It was found that the flow pattern can be well categorized into three regimes. A regular characteristic large vortex was shown for the CO concentration contour when the wind velocity was higher than the critical re-entrainment value. A new formula was theoretically developed to show quantitatively that the critical re-entrainment wind velocities, u(c), for buoyancy source at different floors, were proportional to -1/3 power of the characteristic height. LES simulation results agreed well with theoretical analysis. The critical Froude number was found to be constant of 0.7. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Spanwise homogeneous buoyancy-drag model for Rayleigh-Taylor mixing and experimental evaluation

    International Nuclear Information System (INIS)

    Dimonte, Guy

    2000-01-01

    A buoyancy-drag model for Rayleigh-Taylor (RT) mixing is developed on the premise that the bubble and spike regions behave as distinct and spanwise homogeneous fluids. Then, mass conservation is applied accross the mixing zone to obtain their average mixture densities dynamically. These are used to explicitly calculate the inertia and buoyancy terms in the evolutionary equation. The only unknown parameter in the model is the Newtonian drag constant C∼2.5±0.6, which is determined from turbulent RT experiments over various Atwood numbers A and acceleration histories g(t). The bubble (i=2) and spike (i=1) amplitudes are found to obey the familiar h i =α i Agt 2 for a constant g and h i ∼t θ i for an impulsive g. For bubbles, both α 2 and θ 2 are insensitive to A. For the spikes, both α 1 and θ 1 increase as a power law with the density ratio. However, θ 1 is not universal because it depends on the initial value of h 1 /h 2 . (c) 2000 American Institute of Physics

  10. Numerical Study of the Buoyancy-Driven Flow in a Four-Electrode Rectangular Electrochemical Cell

    Science.gov (United States)

    Sun, Zhanyu; Agafonov, Vadim; Rice, Catherine; Bindler, Jacob

    2009-11-01

    Two-dimensional numerical simulation is done on the buoyancy-driven flow in a four-electrode rectangular electrochemical cell. Two kinds of electrode layouts, the anode-cathode-cathode-anode (ACCA) and the cathode-anode-anode-cathode (CAAC) layouts, are studied. In the ACCA layout, the two anodes are placed close to the channel outlets while the two cathodes are located between the two anodes. The CAAC layout can be converted from the ACCA layout by applying higher electric potential on the two middle electrodes. Density gradient was generated by the electrodic reaction I3^-+2e^- =3I^-. When the electrochemical cell is accelerated axially, buoyancy-driven flow occurs. In our model, electro-neutrality is assumed except at the electrodes. The Navier-Stokes equations with the Boussinesq approximation and the Nernst-Planck equations are employed to model the momentum and mass transports, respectively. It is found that under a given axial acceleration, the electrolyte density between the two middle electrodes determines the bulk flow through the electrochemical cell. The cathodic current difference is found to be able to measure the applied acceleration. Other important electro-hydrodynamic characteristics are also discussed.

  11. Noninvasive embryo assessment technique based on buoyancy and its association with embryo survival after cryopreservation.

    Science.gov (United States)

    Wessels, Cara; Penrose, Lindsay; Ahmad, Khaliq; Prien, Samuel

    2017-11-01

    Embryo cryopreservation offers many benefits by allowing genetic preservation, genetic screening, cost reduction, global embryo transport and single embryo transfer. However, freezing of embryos decreases embryo viability, as intracellular ice crystal formation often damages embryos. Success rates of frozen embryo transfer are expected to be 15-20% less than fresh embryo transfer. We have developed a noninvasive embryo assessment technique (NEAT) which enables us to predict embryo viability based on buoyancy. The purpose of this research was twofold. First was to determine if a NEAT, through a specific gravity device can detect embryo survival of cryopreservation. Second, it was to relate embryo buoyancy to embryo viability for establishing pregnancies in sheep. Blastocysts descent times were measured on one-hundred sixty-nine mice blastocysts before cryopreservation, according to standard protocol and post-thawing blastocysts descent times were measured again. There was a significant difference in blastocyst post-thaw descent times with NEAT in those blastocysts which demonstrated viability from those that did not (P embryos. Further studies on a larger scale commercial setting will evaluate the efficacy of NEAT. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. The effect of centrifugal buoyancy on the heat transport in rotating Rayleigh-Bénard convection

    Science.gov (United States)

    Horn, Susanne; Aurnou, Jonathan

    2017-11-01

    In a rapidly rotating and differentially heated fluid, the centrifugal acceleration can play a similar role to that of gravity in generating convective motion. However, in the paradigm system of rotating Rayleigh-Bénard convection, centrifugal buoyancy is typically not considered in theoretical studies and, thus, usually undesired in laboratory experiments, despite being unavoidable. How centrifugal buoyancy affects the turbulent flow, including the heat transport, is still largely unknown, in particular, when it can be considered negligible. We study this problem by means of direct numerical simulations. Unlike in experiments, we are able to systematically vary the Froude number Fr (ratio of centrifugal to gravitational acceleration) and the Rossby number Ro (dimensionless rotation rate) independently, and even set each to zero exactly. We show that the centrifugal acceleration simultaneously leads to contending phenomena, e.g. reflected by an increase and a decrease of the center temperature, or a suppression and an enhancement of the heat transfer efficiency. Which one prevails as net effect strongly depends on the combination of Fr and Ro. Furthermore, we discuss implications for experiments of rapidly rotating convection. SH acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG) under Grant HO 5890/1-1, JA by the NSF Geophysics Program.

  13. Buoyancy limits on magnetic viscosity stress-law scalings in quasi stellar object accretion disk models

    International Nuclear Information System (INIS)

    Sakimoto, P.J.

    1985-01-01

    Quasi-Stellar Objects (QSOs) are apparently the excessively bright nuclei of distant galaxies. They are thought to be powered by accretion disks surrounding supermassive black holes: however, proof of this presumption is hampered by major uncertainties in the viscous stress necessary for accretion to occur. Models generally assume an and hoc stress law which scales the stress with the total pressure. Near the black hole, radiation pressure dominates gas pressure; scaling the stress with the radiation pressure results in disk models that are thermally unstable and optically thin. This dissertation shows that a radiation pressure scaling for the stress is not possible if the viscosity is due to turbulent magnetic Maxwell stresses. The argument is one of internal self-consistency. First, four model accretion disks that bound the reasonably expected ranges of viscous stress scalings and vertical structures are constructed. Magnetic flux tubes of various initial field strengths are then placed within these models, nd their buoyancy is modeled numerically. In disks using the radiation pressure stress law scaling, low opacities allow rapid heat flow into the flux tubes: the tubes are extremely buoyant, and magnetic fields strong enough to provide the required stress cannot be retained. If an alternative gas pressure scaling for the stress is assumed, then the disks are optically thick; flux tubes have corresponding lower buoyancy, and magnetic fields strong enough to provide the stress can be retained for dynamically significant time periods

  14. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target.

    Science.gov (United States)

    Dubey, P K; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  15. Simulation of buoyancy-induced turbulent flow from a hot horizontal jet

    KAUST Repository

    El-Amin, Mohamed

    2014-02-01

    Experimental visualizations and numerical simulations of a horizontal hot water jet entering cold water into a rectangular storage tank are described. Three different temperature differences and their corresponding Reynolds numbers are considered. Both experimental visualization and numerical computations are carried out for the same flow and thermal conditions. The realizable k - ε model is used for modeling the turbulent flow while the buoyancy is modeled using the Boussinesq approximation. Polynomial approximations of the water properties are used to compare with the Boussinesq approximation. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank as well as the Froude number are analyzed. The experimental visualizations are performed at intervals of five seconds for all different cases. The simulated results are compared with the visualized results, and both of them show the stratification phenomena and buoyancy force effects due to temperature difference and density variation. After certain times, depending on the case condition, the flow tends to reach a steady state. © 2014 Publishing House for Journal of Hydrodynamics.

  16. A Six-DOF Buoyancy Tank Microgravity Test Bed with Active Drag Compensation

    Science.gov (United States)

    Sun, Chong; Chen, Shiyu; Yuan, Jianping; Zhu, Zhanxia

    2017-10-01

    Ground experiment under microgravity is very essential because it can verify the space enabling technologies before applied in space missions. In this paper, a novel ground experiment system that can provide long duration, large scale and high microgravity level for the six degree of freedom (DOF) spacecraft trajectory tracking is presented. In which, the most gravity of the test body is balanced by the buoyancy, and the small residual gravity is offset by the electromagnetic force. Because the electromagnetic force on the test body can be adjusted in the electromagnetic system, it can significantly simplify the balancing process using the proposed microgravity test bed compared to the neutral buoyance system. Besides, a novel compensation control system based on the active disturbance rejection control (ADRC) method is developed to estimate and compensate the water resistance online, in order to improve the fidelity of the ground experiment. A six-DOF trajectory tracking in the microgravity system is applied to testify the efficiency of the proposed compensation controller, and the experimental simulation results are compared to that obtained using the classic proportional-integral-derivative (PID) method. The simulation results demonstrated that, for the six-DOF motion ground experiment, the microgravity level can reach to 5 × 10-4 g. And, because the water resistance has been estimated and compensated, the performance of the presented controller is much better than the PID controller. The presented ground microgravity system can be applied in on-orbit service and other related technologies in future.

  17. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    Science.gov (United States)

    Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-05-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

  18. Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

    International Nuclear Information System (INIS)

    Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

    2014-01-01

    The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique

  19. Maximum Neutral Buoyancy Depth of Juvenile Chinook Salmon: Implications for Survival during Hydroturbine Passage

    Energy Technology Data Exchange (ETDEWEB)

    Pflugrath, Brett D.; Brown, Richard S.; Carlson, Thomas J.

    2012-03-01

    This study investigated the maximum depth at which juvenile Chinook salmon Oncorhynchus tshawytscha can acclimate by attaining neutral buoyancy. Depth of neutral buoyancy is dependent upon the volume of gas within the swim bladder, which greatly influences the occurrence of injuries to fish passing through hydroturbines. We used two methods to obtain maximum swim bladder volumes that were transformed into depth estimations - the increased excess mass test (IEMT) and the swim bladder rupture test (SBRT). In the IEMT, weights were surgically added to the fishes exterior, requiring the fish to increase swim bladder volume in order to remain neutrally buoyant. SBRT entailed removing and artificially increasing swim bladder volume through decompression. From these tests, we estimate the maximum acclimation depth for juvenile Chinook salmon is a median of 6.7m (range = 4.6-11.6 m). These findings have important implications to survival estimates, studies using tags, hydropower operations, and survival of juvenile salmon that pass through large Kaplan turbines typical of those found within the Columbia and Snake River hydropower system.

  20. Density-ratio effects on buoyancy-driven variable-density turbulent mixing

    Science.gov (United States)

    Aslangil, Denis; Livescu, Daniel; Banerjee, Arindam

    2017-11-01

    Density-ratio effects on the turbulent mixing of two incompressible, miscible fluids with different densities subject to constant acceleration are studied by means of high-resolution Direct Numerical Simulations. In a triply periodic domain, turbulence is generated by stirring in response to the differential buoyancy forces within the flow. Later, as the fluids become molecularly mixed, dissipation starts to overcome turbulence generation by bouyancy. Thus, the flow evolution includes both turbulence growth and decay, and it displays features present in the core region of the mixing layer of the Rayleigh-Taylor as well as Richtmyer-Meshkov instabilities. We extend the previous studies by investigating a broad range of density-ratio, from 1-14.4:1, corresponding to Atwood numbers of 0.05-0.87. Here, we focus on the Atwood number dependence of mixing-efficiency, that is defined based on the energy-conversion ratios from potential energy to total and turbulent kinetic energies, the decay characteristics of buoyancy-assisted variable-density homogeneous turbulence, and the effects of high density-ratios on the turbulence structure and mixing process. Authors acknowledge financial support from DOE-SSAA (DE-NA0003195) and NSF CAREER (#1453056) awards.

  1. Level-set simulations of buoyancy-driven motion of single and multiple bubbles

    International Nuclear Information System (INIS)

    Balcázar, Néstor; Lehmkuhl, Oriol; Jofre, Lluís; Oliva, Assensi

    2015-01-01

    Highlights: • A conservative level-set method is validated and verified. • An extensive study of buoyancy-driven motion of single bubbles is performed. • The interactions of two spherical and ellipsoidal bubbles is studied. • The interaction of multiple bubbles is simulated in a vertical channel. - Abstract: This paper presents a numerical study of buoyancy-driven motion of single and multiple bubbles by means of the conservative level-set method. First, an extensive study of the hydrodynamics of single bubbles rising in a quiescent liquid is performed, including its shape, terminal velocity, drag coefficients and wake patterns. These results are validated against experimental and numerical data well established in the scientific literature. Then, a further study on the interaction of two spherical and ellipsoidal bubbles is performed for different orientation angles. Finally, the interaction of multiple bubbles is explored in a periodic vertical channel. The results show that the conservative level-set approach can be used for accurate modelling of bubble dynamics. Moreover, it is demonstrated that the present method is numerically stable for a wide range of Morton and Reynolds numbers.

  2. The Effects of Buoyancy on Characteristics of Turbulent Nonpremixed Jet Flames

    Science.gov (United States)

    Idicheria, Cherian; Boxx, Isaac; Clemens, Noel

    2002-11-01

    This work addresses the influence of buoyant forces on the underlying structure of turbulent nonpremixed jet flames. Buoyancy effects are investigated by studying transitional and turbulent propane and ethylene flames (Re_D=2500-10500) at normal, low and microgravity conditions. The reduced gravity experiments are conducted by dropping a combustion rig in the University of Texas 1.25-second drop tower and the NASA Glenn 2.2-second drop tower. The diagnostic employed is high-speed luminosity imaging using a CCD camera. The images obtained are used to compare flame length, mean, RMS and flame tip oscillation characteristics The results showed that, in contrast to previous studies, the high Reynolds number flames at all gravity levels were essentially identical. Furthermore, the parameter ξL (Becker and Yamazaki, 1978) is sufficient for quantifying the effects of buoyancy on the flame characteristics. The large-scale structure and flame tip dynamics are essentially identical to those of purely momentum driven flames provided ξL is less than approximately 3.

  3. Expatriate academics

    DEFF Research Database (Denmark)

    Selmer, Jan; Lauring, Jakob

    2011-01-01

    Purpose – The literature on business expatriates has been increasing rapidly, but research on expatriate academics has remained scant, despite the apparent increasing globalisation of the academic world. Therefore, more research is needed on the latter group of expatriates. This paper aims to fill...... some of the gaps. Design/methodology/approach – A questionnaire was directed electronically towards expatriate academics occupying regular positions in science faculty departments in universities in northern Europe. Findings – Results showed that job clarity was the dominating job factor with strong...... relationships with all of the five investigated work outcome variables, work adjustment, work performance, work effectiveness, job satisfaction, and time to proficiency. Job conflict and job freedom had an association with some of the work outcome variables but not with all of them. Neither workload nor job...

  4. Academic Allies

    DEFF Research Database (Denmark)

    Byberg, Rebekka Birkebo

    the national associations of European law: Fédération Internationale pour le Droit Européen, the European law journal Common Market Law Review, and the ITL project, carried out at the European University Institute.It carefully documents an alliance between academics and community actors with the aim...... of providing academic support to the constitutional claim, and it argues that the academic discipline of European law was built and developed through a circular attribution of legal ideas, legitimacy, and self-image between the European Court of Justice, the Commission, and academia –most particularly so......This doctoral thesis explores the key transnational institutions of European law academia and their role in the creation of a constitutional legal practice in the European Community from 1961 to 1993. Consisting of three case studies, it investigates the transnational federation gathering...

  5. Effect of buoyancy on fuel containment in an open-cycle gas-core nuclear rocket engine.

    Science.gov (United States)

    Putre, H. A.

    1971-01-01

    Analysis aimed at determining the scaling laws for the buoyancy effect on fuel containment in an open-cycle gas-core nuclear rocket engine, so conducted that experimental conditions can be related to engine conditions. The fuel volume fraction in a short coaxial flow cavity is calculated with a programmed numerical solution of the steady Navier-Stokes equations for isothermal, variable density fluid mixing. A dimensionless parameter B, called the Buoyancy number, was found to correlate the fuel volume fraction for large accelerations and various density ratios. This parameter has the value B = 0 for zero acceleration, and B = 350 for typical engine conditions.

  6. Effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Butts, Ian; Munk, Peter

    2016-01-01

    sizes, while the remaining four salt types resulted in smaller eggs. All salt types except NaCl treatments led to high fertilization rates and had no effect on fertilization success as well as egg neutral buoyancies at 7 h post-fertilization. The study points to the importance of considering ionic...... and egg buoyancy. Egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. Activation salinities between 30–40 practical salinity unit (psu) produced higher quality eggs and generally larger egg diameters. Chorion...

  7. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    12, 13, 14, March LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 POSTPONED! - Modern Project Management Methods - POSTPONED! By G. Vallet / Ed. Highware, Paris, F. Academic Training Françoise Benz Secretariat Tel. 73127 francoise.benz@cern.ch

  8. Academic Cloning.

    Science.gov (United States)

    Sikula, John P.; Sikula, Andrew F.

    1980-01-01

    The authors define "cloning" as an integral feature of all educational systems, citing teaching practices which reward students for closely reproducing the teacher's thoughts and/or behaviors and administrative systems which tend to promote like-minded subordinates. They insist, however, that "academic cloning" is not a totally…

  9. Academic Aspirations

    Science.gov (United States)

    Durant, Linda

    2013-01-01

    As colleges and universities become even more complex organizations, advancement professionals need to have the skills, experience, and academic credentials to succeed in this ever-changing environment. Advancement leaders need competencies that extend beyond fundraising, alumni relations, and communications and marketing. The author encourages…

  10. Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage

    KAUST Repository

    Allen, Rebecca

    2015-04-01

    ABSTRACT Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage Rebecca Allen Geological CO2 storage is an engineering feat that has been undertaken around the world for more than two decades, thus accurate modeling of flow and transport behavior is of practical importance. Diffusive and convective transport are relevant processes for buoyancy-driven convection of CO2 into underlying fluid, a scenario that has received the attention of numerous modeling studies. While most studies focus on Darcy-scale modeling of this scenario, relatively little work exists at the pore-scale. In this work, properties evaluated at the pore-scale are used to investigate the transport behavior modeled at the Darcy-scale. We compute permeability and two different forms of tortuosity, namely hydraulic and diffusive. By generating various pore ge- ometries, we find hydraulic and diffusive tortuosity can be quantitatively different in the same pore geometry by up to a factor of ten. As such, we emphasize that these tortuosities should not be used interchangeably. We find pore geometries that are characterized by anisotropic permeability can also exhibit anisotropic diffusive tortuosity. This finding has important implications for buoyancy-driven convection modeling; when representing the geological formation with an anisotropic permeabil- ity, it is more realistic to also account for an anisotropic diffusivity. By implementing a non-dimensional model that includes both a vertically and horizontally orientated 5 Rayleigh number, we interpret our findings according to the combined effect of the anisotropy from permeability and diffusive tortuosity. In particular, we observe the Rayleigh ratio may either dampen or enhance the diffusing front, and our simulation data is used to express the time of convective onset as a function of the Rayleigh ratio. Also, we implement a lattice Boltzmann model for thermal convective flows, which we treat as an analog for

  11. Academic Words and Academic Capitalism Academic Words and Academic Capitalism

    Directory of Open Access Journals (Sweden)

    Michael Billig

    2013-03-01

    Full Text Available

    Este artículo sugiere que esta época es la mejor y peor para la labor académica. La mejor en cuanto hay más publicaciones académicas que nunca. Y la peor porque sobra mucho de estas publicaciones. Trabajando en las condiciones competitivas del capitalismo académico, los académicos se sienten en la necesidad de continuar publicando, independientemente de que tengan algo que decir. Las presiones de publicar continuamente y promover la propia perspectiva se reflejan en la manera en la que los científicos sociales están escribiendo. Y es que los académicos utilizan un lenguaje técnico basado en sustantivos, con una precisión menor a la del lenguaje ordinario. Los estudiantes de postgrado han sido educados en esta manera de escribir como una condición previa a iniciarse en las ciencias sociales. Así, la naturaleza misma del capitalismo académico no sólo determina las condiciones en las que los académicos trabajan, sino que también afecta su manera de escribir.


    This paper suggests that it is the best and worst of times for academic work. It is the best of times because there are more academics publishing than ever before. It is the worst of times because there is much unnecessary publication. Working in the competitive conditions of academic capitalism, academics feel impelled to keep publishing, whether or not they have anything to say. The pressures to publish continually and to promote one’s own approach are reflected in the way that social scientists are writing. Academics use a noun-based technical language, which is less precise than ordinary language. Postgraduates are taught this way of writing as a precondition for entering the social sciences. In this way, the nature of academic capitalism not only determines the conditions under which academics are working but it affects the way that they are writing.

  12. Buoyancy effects on thermal behavior of a flat-plate solar collector

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon

    2008-01-01

    Theoretical and experimental investigations of the flow and temperature distribution in a 12.53 m(2) solar collector panel with an absorber consisting of two vertical manifolds interconnected by 16 parallel horizontal fins have been carried out. The investigations are focused on overheating...... and the influence of the buoyancy effects are considered in the investigations. Further experimental investigations of the solar collector panel are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the back of the absorber tubes. The measured temperatures....... The CFD calculations elucidate the flow and temperature distribution in the collector panels of different designs. Based on the investigations, recommendations are given in order to avoid overheating or boiling problems in the solar collector panel....

  13. Numerical investigation on thermal performance and correlations of double skin facade with buoyancy-driven airflow

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, Alexandra; Zhai, Zhiqiang [Department of Civil, Environmental and Architectural Engineering, University of Colorado, UCB 428, ECOT 441, Boulder, CO 80309-0428 (United States)

    2008-07-01

    This paper briefly reviews the primary parameters for a double skin facade (DSF) design. The research presents an integrated and iterative modeling process for analyzing the thermal performance of DSF cavities with buoyancy-driven airflow by using a building energy simulation program (BESP) along with a computational fluid dynamics (CFD) package. A typical DSF cavity model has been established and simulated. The model and the modeling process have been calibrated and validated against the experimental data. The validated model was used to develop correlations that can be implemented in a BESP, allowing users to take advantage of the accuracy gained from CFD simulations without the required computation time. Correlations were developed for airflow rate through cavity, average and peak cavity air temperature, cavity air pressure, and interior convection coefficient. The correlations are valuable for 'back of the envelope' calculation and for examining accuracy of zonal-model-based energy and airflow simulation programs. (author)

  14. Buoyancy driven flow in a hot water tank due to standby heat loss

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon

    2012-01-01

    Results of experimental and numerical investigations of thermal behavior in a vertical cylindrical hot water tank due to standby heat loss of the tank are presented. The effect of standby heat loss on temperature distribution in the tank is investigated experimentally on a slim 150l tank...... show that the CFD model predicts satisfactorily water temperatures at different levels of the tank during cooling by standby heat loss. It is elucidated how the downward buoyancy driven flow along the tank wall is established by the heat loss from the tank sides and how the natural convection flow...... with a height to diameter ratio of 5. A tank with uniform temperatures and with thermal stratification is studied. A detailed computational fluid dynamics (CFD) model of the tank is developed to calculate the natural convection flow in the tank. The distribution of the heat loss coefficient for the different...

  15. The buoyancy convection during directional solidification of AlZn eutectic

    International Nuclear Information System (INIS)

    Prazak, M.; Procio, M.; Holecek, S.

    1993-01-01

    A study has been made of the effect of buoyancy convection during the directional solidification of AlZn eutectic alloy. Experiments have been conducted using a Bridgman-Stockbarger arrangement with the furnace moving along the specimen. The apparatus rotated around the horizontal axis, which made it possible to carry out measurements at different angles β contained by the gravity and temperature gradient vectors in the specimen. The anisotropy of both the linear thermal expansion coefficient a and the hardness HK measured by the Knoop method has been studied. The dilatation measurements confirmed the expected anisotropy of the linear thermal expansion of directionally solidified specimens. The values of HK correspond with the lamellar spacing measured in the metallographic study. (orig.)

  16. Kinetic energy and scalar spectra in high Rayleigh number axially homogeneous buoyancy driven turbulence

    Science.gov (United States)

    Pawar, Shashikant S.; Arakeri, Jaywant H.

    2016-06-01

    Kinetic energy and scalar spectra from the measurements in high Rayleigh number axially homogeneous buoyancy driven turbulent flow are presented. Kinetic energy and concentration (scalar) spectra are obtained from the experiments wherein density difference is created using brine and fresh water and temperature spectra are obtained from the experiments in which heat is used. Scaling of the frequency spectra of lateral and longitudinal velocity near the tube axis is closer to the Kolmogorov-Obukhov scaling, while the scalar spectra show some evidence of dual scaling, Bolgiano-Obukhov scaling followed by Obukhov-Corrsin scaling. These scalings are also observed in the corresponding second order spatial structure functions of velocity and concentration fluctuations.

  17. Education of Gifted Students with Virtual Physics Laboratory: Buoyancy Force Topic

    Directory of Open Access Journals (Sweden)

    Necati HIRCA

    2013-06-01

    Full Text Available Project-based learning approach is recommended for science education of gifted students for their independent learning will and they can intensify their attention on any issue for along time. In this study, the steps of the experiment buoyancy of liquids has been explained with the help of Algodoo Programme a learning environment in which gifted students test their hypotheses and can learn the concepts of physics with their own experiences. This study is tought to be used as a guidance material in the education of gifted students in Science and Art Centers in Turkey. Teachers in Science and Art Center (or who educate gifted students are generally inexperienced in the education of gifted students. Another problem of these teachers is the lack of adequate materials that the teachers use in the education of gifted students.

  18. Positive segregation as a function of buoyancy force during steel ingot solidification

    International Nuclear Information System (INIS)

    Radovic, Zarko; Jaukovic, Nada; Lalovic, Milisav; Tadic, Nebojsa

    2008-01-01

    We analyze theoretically and experimentally solute redistribution in the dendritic solidification process and positive segregation during solidification of steel ingots. Positive segregation is mainly caused by liquid flow in the mushy zone. Changes in the liquid steel velocity are caused by the temperature gradient and by the increase in the solid fraction during solidification. The effects of buoyancy and of the change in the solid fraction on segregation intensity are analyzed. The relationships between the density change, liquid fraction and the steel composition are considered. Such elements as W, Ni, Mo and Cr decrease the effect of the density variations, i.e. they show smaller tendency to segregate. Based on the modeling and experimental results, coefficients are provided controlling the effects of chemical composition, secondary dendrite arm spacing and the solid fraction.

  19. Analysis of the strength of sea gas pipelines of positive buoyancy conditioned by glaciation

    Science.gov (United States)

    Malkov, Venyamin; Kurbatova, Galina; Ermolaeva, Nadezhda; Malkova, Yulia; Petrukhin, Ruslan

    2018-05-01

    A technique for estimating the stress state of a gas pipeline laid along the seabed in northern latitudes in the presence of glaciation is proposed. It is assumed that the pipeline lies on the bottom of the seabed, but under certain conditions on the some part of the pipeline a glaciation is formed and the gas pipeline section in the place of glaciation can come off the ground due to the positive buoyancy of the ice. Calculation of additional stresses caused by bending of the pipeline is of practical interest for strength evaluation. The gas pipeline is a two-layer cylindrical shell of circular cross section. The inner layer is made of high-strength steel, the outer layer is made of reinforced ferroconcrete. The proposed methodology for calculating the gas pipeline for strength is based on the equations of the theory of shells. The procedure takes into account the effect of internal gas pressure, external pressure of sea water, the weight of two-layer gas pipeline and the weight of the ice layer. The lifting force created by the displaced fluid and the positive buoyancy of the ice is also taken into account. It is significant that the listed loads cause only two types of deformation of the gas pipeline: axisymmetric and antisymmetric. The interaction of the pipeline with the ground as an elastic foundation is not considered. The main objective of the research is to establish the fact of separation of part of the pipeline from the ground. The method of calculations of stresses and deformations occurring in a model sea gas pipeline is presented.

  20. How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers’ Hydrostatic and Hydrodynamic Profiles?

    Science.gov (United States)

    Barbosa, Tiago M.; Costa, Mário J.; Morais, Jorge E; Moreira, Marc; Silva, António J.; Marinho, Daniel A.

    2012-01-01

    The aim of this research was to develop a path-flow analysis model to highlight the relationships between buoyancy and prone gliding tests and some selected anthropometrical and biomechanical variables. Thirty-eight young male swimmers (12.97 ± 1.05 years old) with several competitive levels were evaluated. It were assessed the body mass, height, fat mass, body surface area, vertical buoyancy, prone gliding after wall push-off, stroke length, stroke frequency and velocity after a maximal 25 [m] swim. The confirmatory model included the body mass, height, fat mass, prone gliding test, stroke length, stroke frequency and velocity. All theoretical paths were verified except for the vertical buoyancy test that did not present any relationship with anthropometrical and biomechanical variables nor with the prone gliding test. The good-of-fit from the confirmatory path-flow model, assessed with the standardized root mean square residuals (SRMR), is considered as being close to the cut-off value, but even so not suitable of the theory (SRMR = 0.11). As a conclusion, vertical buoyancy and prone gliding tests are not the best techniques to assess the swimmer’s hydrostatic and hydrodynamic profile, respectively. PMID:23486528

  1. Experimental aspects of buoyancy correction in measuring reliable high-pressure excess adsorption isotherms using the gravimetric method

    Science.gov (United States)

    Nguyen, Huong Giang T.; Horn, Jarod C.; Thommes, Matthias; van Zee, Roger D.; Espinal, Laura

    2017-12-01

    Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO2 and supercritical N2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

  2. Academic Practice

    DEFF Research Database (Denmark)

    Nielsen, Sandro; Heine, Carmen

    Vejledning i at undgå plagiering ved at følge de normer, der gælder for good academic practice. Dette indebærer at man angiver kilder korrekt, og når det er nødvendigt, og at man har en korrekt udformet fortegnelse over referencer. Vejledningen indeholder konkrete eksempler på korrekt kildeangive......Vejledning i at undgå plagiering ved at følge de normer, der gælder for good academic practice. Dette indebærer at man angiver kilder korrekt, og når det er nødvendigt, og at man har en korrekt udformet fortegnelse over referencer. Vejledningen indeholder konkrete eksempler på korrekt...

  3. Language experience changes subsequent learning

    Science.gov (United States)

    Onnis, Luca; Thiessen, Erik

    2013-01-01

    What are the effects of experience on subsequent learning? We explored the effects of language-specific word order knowledge on the acquisition of sequential conditional information. Korean and English adults were engaged in a sequence learning task involving three different sets of stimuli: auditory linguistic (nonsense syllables), visual non-linguistic (nonsense shapes), and auditory non-linguistic (pure tones). The forward and backward probabilities between adjacent elements generated two equally probable and orthogonal perceptual parses of the elements, such that any significant preference at test must be due to either general cognitive biases, or prior language-induced biases. We found that language modulated parsing preferences with the linguistic stimuli only. Intriguingly, these preferences are congruent with the dominant word order patterns of each language, as corroborated by corpus analyses, and are driven by probabilistic preferences. Furthermore, although the Korean individuals had received extensive formal explicit training in English and lived in an English-speaking environment, they exhibited statistical learning biases congruent with their native language. Our findings suggest that mechanisms of statistical sequential learning are implicated in language across the lifespan, and experience with language may affect cognitive processes and later learning. PMID:23200510

  4. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    6, 7 May LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Decoding the Human Genome, Scientific basis and ethic and social aspects by S.E. Antonarakis and A. Mauron / Univ. of Geneva Decoding the Human genome is a very up-to-date topic, raising several questions besides purely scientific, in view of the two competing teams (public and private), the ethics of using the results, and the fact that the project went apparently faster and easier than expected. The lecture series will address the following chapters: Scientific basis and challenges, Ethical and social aspects of genomics. Academic Training Françoise Benz Tel. 73127

  5. Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy.

    Science.gov (United States)

    Ponganis, P J; St Leger, J; Scadeng, M

    2015-03-01

    The anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body O2 store, buoyancy and hence the overall diving physiology of penguins. Therefore, three-dimensional reconstructions from computerized tomographic (CT) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [Adélie (Pygoscelis adeliae), king (Aptenodytes patagonicus) and emperor (A. forsteri) penguins]. Lung volumes scaled to body mass according to published avian allometrics. Air sac volumes at 30 cm H2O (2.94 kPa) inflation pressure, the assumed maximum volume possible prior to deep dives, were two to three times allometric air sac predictions and also two to three times previously determined end-of-dive total air volumes. Although it is unknown whether penguins inhale to such high volumes prior to dives, these values were supported by (a) body density/buoyancy calculations, (b) prior air volume measurements in free-diving ducks and (c) previous suggestions that penguins may exhale air prior to the final portions of deep dives. Based upon air capillary volumes, parabronchial volumes and tracheobronchial volumes estimated from the measured lung/airway volumes and the only available morphometry study of a penguin lung, the presumed maximum air sac volumes resulted in air sac volume to air capillary/parabronchial/tracheobronchial volume ratios that were not large enough to prevent barotrauma to the non-collapsing, rigid air capillaries during the deepest dives of all three species, and during many routine dives of king and emperor penguins. We conclude that volume reduction of airways and lung air spaces, via compression, constriction or blood engorgement, must occur to provide pulmonary baroprotection at depth. It is also possible that relative air capillary and parabronchial volumes are

  6. SIMULATION OF FREE CURRENT FLOWS IN BUOYANCY-DRIVEN VENTILATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    D. V. Abramkina

    2017-01-01

    Full Text Available Objectives. The aim of the study is to analyse the effect of the design and methods for heating the ventilation duct of a buoyancy- driven system on the formation of free convective air currents in it.Methods. The study of free convection under the conditions of interior problem was carried out using the CFD software, based on  the finite volume method with unstructured grid. Ansys Fluent software was used as a calculation tool in the study, due to its having a high convergence of numerical solutions offering full-scale  measurements of convective currents.To evaluate the reliability of  the results obtained, a validation procedure was carried out, allowing us to determine how accurately the selected conceptual model describes the investigated flow through a comparison of experimental and numerical data.Results. The results of numerical modelling of free convective currents occurring in the heated channel of the ventilation system of  the top floor of a multi-storey residential building are presented in  the article. In the course of the study, the air velocity at the entrance to the ventilation duct was found to depend on the calculated  temperature difference θ ˚C for various heating methods. A gradual  increase in the discrepancy between the numerical simulation and  experimental results is observed if the calculated temperature  difference > 20 ° C. This phenomenon is due to the fact that with  increased duct temperature, it is quite difficult to achieve even  heating under actual conditions; this is especially noticeable when  considering the variant when the vertical part of the vent duct and the take-off are both heated. The maximum deviation of the  results is 4.4%. The obtained velocity profiles in the calculated  sections indicate the impact of the ventilation take-off on the nature  of the air flow motion.Conclusion. One of the drawbacks of the existing systems of natural ventilation of residential

  7. Importance of initial buoyancy field on evolution of mantle thermal structure: Implications of surface boundary conditions

    Directory of Open Access Journals (Sweden)

    Petar Glišović

    2015-01-01

    Full Text Available Although there has been significant progress in the seismic imaging of mantle heterogeneity, the outstanding issue that remains to be resolved is the unknown distribution of mantle temperature anomalies in the distant geological past that give rise to the present-day anomalies inferred by global tomography models. To address this question, we present 3-D convection models in compressible and self-gravitating mantle initialised by different hypothetical temperature patterns. A notable feature of our forward convection modelling is the use of self-consistent coupling of the motion of surface tectonic plates to the underlying mantle flow, without imposing prescribed surface velocities (i.e., plate-like boundary condition. As an approximation for the surface mechanical conditions before plate tectonics began to operate we employ the no-slip (rigid boundary condition. A rigid boundary condition demonstrates that the initial thermally-dominated structure is preserved, and its geographical location is fixed during the evolution of mantle flow. Considering the impact of different assumed surface boundary conditions (rigid and plate-like on the evolution of thermal heterogeneity in the mantle we suggest that the intrinsic buoyancy of seven superplumes is most-likely resolved in the tomographic images of present-day mantle thermal structure. Our convection simulations with a plate-like boundary condition reveal that the evolution of an initial cold anomaly beneath the Java-Indonesian trench system yields a long-term, stable pattern of thermal heterogeneity in the lowermost mantle that resembles the present-day Large Low Shear Velocity Provinces (LLSVPs, especially below the Pacific. The evolution of subduction zones may be, however, influenced by the mantle-wide flow driven by deeply-rooted and long-lived superplumes since Archean times. These convection models also detect the intrinsic buoyancy of the Perm Anomaly that has been identified as a unique

  8. Buoyed by geophysics : geophysics, just-in-time procurement help save millions on Ekwan pipeline buoyancy control

    Energy Technology Data Exchange (ETDEWEB)

    Roche, P.

    2005-09-01

    Large-diameter natural gas pipelines buried in wet muskeg have the potential to rise to the surface due to buoyancy. Until recently, the most reliable method to prevent this was to attach specially manufactured bolt-on concrete weights at closely spaced intervals. However, these weights significantly increase capital budgets by millions of dollars because each weight weighs 2,540 kg and costs $1,000. A less costly alternative for buoyancy control in shallow muskeg is for the contractor to simply dig a deeper ditch. Another option is to hold down the pipeline by polyester straps attached to screw anchors. The challenge of applying these less costly options is that heavy equipment cannot be brought to the site to determine ground conditions until after all procurement, assessment and design is completed. Engineers must therefore select a buoyancy control measure based only on air photos and possibly a few drill holes. However, air photos do not indicate the depth of muskeg. Although some muskeg areas may turn out to be thick enough to avoid buoyancy control altogether, once construction is underway, it is too late to opt for cheaper alternatives. EnCana Corporation's 24-inch Ekwan pipeline was recently constructed through a remote area of British Columbia to connect the Greater Sierra natural gas discovery to a tie-in point on Nova Gas Transmission's northwest mainline. Air photos indicated that half of the route was through muskeg. AMEC E and C Services Inc. was responsible for the engineering and management of the project. The company used a combination of geophysical techniques to learn about the ground conditions. Toboggan mounted portable equipment was hauled by snowmobiles along trails made earlier by the survey crews. Ground penetrating radar assessed the muskeg thickness. Fixed frequency electromagnetic surveys also enhanced the results of the ground penetrating radar. The number of bolt-on weights was reduced from 9,000 to 3,700, a savings of $3

  9. Influence of thermal buoyancy on vertical tube bundle thermal density head predictions under transient conditions

    International Nuclear Information System (INIS)

    Lin, H.C.; Kasza, K.E.

    1984-01-01

    The thermal-hydraulic behavior of an LMFBR system under various types of plant transients is usually studied using one-dimensional (1-D) flow and energy transport models of the system components. Many of the transient events involve the change from a high to a low flow with an accompanying change in temperature of the fluid passing through the components which can be conductive to significant thermal bouyancy forces. Thermal bouyancy can exert its influence on system dynamic energy transport predictions through alterations of flow and thermal distributions which in turn can influence decay heat removal, system-response time constants, heat transport between primary and secondary systems, and thermal energy rejection at the reactor heat sink, i.e., the steam generator. In this paper the results from a comparison of a 1-D model prediction and experimental data for vertical tube bundle overall thermal density head and outlet temperature under transient conditions causing varying degrees of thermal bouyancy are presented. These comparisons are being used to generate insight into how, when, and to what degree thermal buoyancy can cause departures from 1-D model predictions

  10. Stereo Imaging Velocimetry of Mixing Driven by Buoyancy Induced Flow Fields

    Science.gov (United States)

    Duval, W. M. B.; Jacqmin, D.; Bomani, B. M.; Alexander, I. J.; Kassemi, M.; Batur, C.; Tryggvason, B. V.; Lyubimov, D. V.; Lyubimova, T. P.

    2000-01-01

    Mixing of two fluids generated by steady and particularly g-jitter acceleration is fundamental towards the understanding of transport phenomena in a microgravity environment. We propose to carry out flight and ground-based experiments to quantify flow fields due to g-jitter type of accelerations using Stereo Imaging Velocimetry (SIV), and measure the concentration field using laser fluorescence. The understanding of the effects of g-jitter on transport phenomena is of great practical interest to the microgravity community and impacts the design of experiments for the Space Shuttle as well as the International Space Station. The aim of our proposed research is to provide quantitative data to the community on the effects of g-jitter on flow fields due to mixing induced by buoyancy forces. The fundamental phenomenon of mixing occurs in a broad range of materials processing encompassing the growth of opto-electronic materials and semiconductors, (by directional freezing and physical vapor transport), to solution and protein crystal growth. In materials processing of these systems, crystal homogeneity, which is affected by the solutal field distribution, is one of the major issues. The understanding of fluid mixing driven by buoyancy forces, besides its importance as a topic in fundamental science, can contribute towards the understanding of how solutal fields behave under various body forces. The body forces of interest are steady acceleration and g-jitter acceleration as in a Space Shuttle environment or the International Space Station. Since control of the body force is important, the flight experiment will be carried out on a tunable microgravity vibration isolation mount, which will permit us to precisely input the desired forcing function to simulate a range of body forces. To that end, we propose to design a flight experiment that can only be carried out under microgravity conditions to fully exploit the effects of various body forces on fluid mixing. Recent

  11. Buoyancy and Pressure Driven Flow of Hot Gases in Vertical Shafts with Natural and Forced Ventilation

    Science.gov (United States)

    Tamm, Gunnar; Jaluria, Yogesh

    2003-11-01

    An experimental investigation has been carried out on the buoyancy and pressure induced flow of hot gases in vertical shafts, in order to simulate the propagation of combustion products in elevator shafts due to fire in multilevel buildings. Various geometrical configurations are studied, with regard to natural and forced ventilation imposed at the top or bottom of the vertical shaft. The aspect ratio is taken at a fixed value of 6 and the inflow conditions for the hot gases, at a vent near the bottom, are varied in terms of the Reynolds and Grashof numbers. Temperature measurements within the shaft allow a detailed study of the steady state thermal fields, from which optimal means for smoke alleviation in high-rise building fires may be developed. Flow visualization is also used to study the flow characteristics. The results obtained indicate a wall plume as the primary transport mechanism. Flow recirculation dominates at high Grashof number flows, while increased Reynolds numbers gives rise to greater mixing in the shaft. The development and stability of the flow and its effect on the spread of smoke and hot gases are assessed for the different shaft configurations and inlet conditions. It is found that the fastest smoke removal and lowest shaft temperatures occur for a configuration with natural ventilation at the top and forced ventilation up from the shaft bottom. It is also shown that forced ventilation can be used to arrest smoke spread, as well as to dilute the effects of the fire.

  12. Radiative effects on turbulent buoyancy-driven air flow in open square cavities

    International Nuclear Information System (INIS)

    Zamora, B.; Kaiser, A.S.

    2016-01-01

    The effects of the radiative effects and the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low- Reynolds k-ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide range of the Rayleigh number varying from 10 3 to 10 16 . The results obtained taking into account the variable thermophysical properties of air are compared to those calculated assuming constant properties and the Boussinesq approximation. In addition, the influence of considering surface radiative effects on the differences reached for the Nusselt number and the mass flow rate obtained with several intensities of heating is studied; specifically, the effects of thermal radiation on the appearance of the burnout phenomenon is analyzed. The changes produced in the flow patterns into the cavity when the radiative heat transfer and the effects of variation of properties are relevant, are also shown. (authors)

  13. Magma buoyancy and volatile ascent driving autocyclic eruptivity at Hekla Volcano (Iceland)

    Science.gov (United States)

    Hautmann, Stefanie; Sacks, I. Selwyn; Linde, Alan T.; Roberts, Matthew J.

    2017-09-01

    Volcanic eruptions are typically accompanied by ground deflation due to the withdrawal of magma from depth and its effusion at the surface. Here, based on continuous high-resolution borehole strain data, we show that ground deformation was absent during the major effusion phases of the 1991 and 2000 eruptions of Hekla Volcano, Iceland. This lack of surface deformation challenges the classic model of magma intrusion/withdrawal as source for volcanic ground uplift/subsidence. We incorporate geodetic and geochemical observables into theoretical models of magma chamber dynamics in order to constrain quantitatively alternative co- and intereruptive physical mechanisms that govern magma propagation and system pressurization. We find the lack of surface deformation during lava effusion to be linked to chamber replenishment from below whilst magma migrates as a buoyancy-driven flow from the magma chamber towards the surface. We further demonstrate that intereruptive pressure build-up is likely to be generated by volatile ascent within the chamber rather than magma injection. Our model explains the persistent periodic eruptivity at Hekla throughout historic times with self-initiating cycles and is conceptually relevant to other volcanic systems.

  14. Suppression of atmospheric recycling of planets embedded in a protoplanetary disc by buoyancy barrier

    Science.gov (United States)

    Kurokawa, Hiroyuki; Tanigawa, Takayuki

    2018-06-01

    The ubiquity of super-Earths poses a problem for planet formation theory to explain how they avoided becoming gas giants. Rapid recycling of the envelope gas of planets embedded in a protoplanetary disc has been proposed to delay the cooling and following accretion of disc gas. We compare isothermal and non-isothermal 3D hydrodynamical simulations of the gas flow past a planet to investigate the influence on the feasibility of the recycling mechanism. Radiative cooling is implemented by using the β cooling model. We find that, in either case, gas enters the Bondi sphere at high latitudes and leaves through the midplane regions, or vice versa when disc gas rotates sub-Keplerian. However, in contrast to the isothermal case where the recycling flow reaches the deeper part of the envelope, the inflow is inhibited from reaching the deep envelope in the non-isothermal case. Once the atmosphere starts cooling, buoyant force prevents the high-entropy disc gas from intruding the low-entropy atmosphere. We suggest that the buoyancy barrier isolates the lower envelope from the recycling and allows further cooling, which may lead runaway gas accretion onto the core.

  15. Turbulent mixed buoyancy driven flow and heat transfer in lid driven enclosure

    International Nuclear Information System (INIS)

    Mishra, Ajay Kumar; Sharma, Anil Kumar

    2015-01-01

    Turbulent mixed buoyancy driven flow and heat transfer of air in lid driven rectangular enclosure has been investigated for Grashof number in the range of 10 8 to 10 11 and for Richardson number 0.1, 1 and 10. Steady two dimensional Reynolds-Averaged-Navier-Stokes equations and conservation equations of mass and energy, coupled with the Boussinesq approximation, are solved. The spatial derivatives in the equations are discretized using the finite-element method. The SIMPLE algorithm is used to resolve pressure-velocity coupling. Turbulence is modeled with the k-ω closure model with physical boundary conditions along with the Boussinesq approximation, for the flow and heat transfer. The predicted results are validated against benchmark solutions reported in literature. The results include stream lines and temperature fields are presented to understand flow and heat transfer characteristics. There is a marked reduction in mean Nusselt number (about 58%) as the Richardson number increases from 0.1 to 10 for the case of Ra=10 10 signifying the effect of reduction of top lid velocity resulting in reduction of turbulent mixing. (author)

  16. Buoyancy Induced Heat Transfer and Fluid Flow Inside a Prismatic Cavity

    International Nuclear Information System (INIS)

    Aich, Walid; Omri, Ahmed; Ben Nasrallah, Sassi

    2009-01-01

    This paper deals with a numerical simulation of natural convection flows in a prismatic cavity. This configuration represents solar energy collectors, conventional attic spaces of greenhouses and buildings with pitched roofs. The third dimension of the cavity is considered long enough for the flow to be considered 2D. The base is submitted to a uniform heat flux, the two top inclined walls are symmetrically cooled and the two vertical walls are assumed to be perfect thermal insulators. The aim of the study is to examine the thermal exchange by natural convection and effects of buoyancy forces on flow structure. The study provides useful information on the flow structure sensitivity to the governing parameters, the Rayleigh number (Ra) and the aspect ratio of the cavity. The hydrodynamic and thermal fields, the local Nusselt number, the temperature profile at the bottom and at the center of the cavity are investigated for a large range of Ra. The effect of the aspect ratio is examined for different values of Ra. Based on the authors knowledge, no previous results on natural convection in this geometry exist

  17. Flow rate measurement of buoyancy-driven exchange flow by laser Doppler velocimeter

    International Nuclear Information System (INIS)

    Fumizawa, Motoo

    1993-01-01

    An experimental investigation was carried out for the buoyancy-driven exchange flow in a narrow vented cylinder concerning the air ingress process during a standing pipe rupture in a high-temperature gas-cooled reactor. In the present study, the evaluation method of exchange flow was developed by measuring the velocity distribution in the cylinder using a laser Doppler velocimeter. The experiments were performed under atmospheric pressure with nitrogen as a working fluid. Rayleigh numbers ranged from 2.0x10 4 to 2.1x10 5 . The exchange flow fluctuated irregularly with time and space in the cylinder. It was found that the exchange velocity distribution along the horizontal axis changed from one-hump to two-hump distribution with increasing Rayleigh number. In the case that the hemisphere wall was cooler than the heated disk, the volumetric exchange flow rate was smaller than that in the case where the hemisphere wall and the heated disk were at the same temperature. (author)

  18. Marangoni-buoyancy convection in binary fluids under varying noncondensable concentrations

    Science.gov (United States)

    Li, Yaofa; Yoda, Minami

    2014-11-01

    Marangoni-buoyancy convection in binary fluids in the presence of phase change is a complex and poorly understood problem. Nevertheless, this flow is of interest in evaporative cooling because solutocapillary stresses could reduce film dryout. Convection was therefore studied in methanol-water (MeOH-H2O) layers of depth h ~ 1 - 3 mm confined in a sealed rectangular cell driven by horizontal temperature differences of ~6° C applied over ~ 5 cm. Particle-image velocimetry (PIV) was used to study how varying the fraction of noncondensables (i.e., air) ca from ~ 7 mol% to ambient conditions in the vapor space affects soluto- and thermocapillary stresses in this flow. Although solutocapillary stresses can be used to drive the flow towards hot regions, solutocapillarity appears to have the greatest effect on the flow at small ca, because noncondensables suppress phase change and hence the gradient in the liquid-phase composition at the interface. Surprisingly, convection at ca ~ 50 % leads to a very weak flow and significant condensation in the central portion of the layer i.e., away from the heated and cooled walls). Supported by ONR.

  19. Direct numerical simulation of vacillation in convection induced by centrifugal buoyancy

    Science.gov (United States)

    Pitz, Diogo B.; Marxen, Olaf; Chew, John W.

    2017-11-01

    Flows induced by centrifugal buoyancy occur in industrial systems, such as in the compressor cavities of gas turbines, as well as in flows of geophysical interest. In this numerical study we use direct numerical simulation (DNS) to investigate the transition between the steady waves regime, which is characterized by great regularity, to the vacillation regime, which is critical to understand transition to the fully turbulent regime. From previous work it is known that the onset of convection occurs in the form of pairs of nearly-circular rolls which span the entire axial length of the cavity, with small deviations near the parallel, no-slip end walls. When non-linearity sets in triadic interactions occur and, depending on the value of the centrifugal Rayleigh number, the flow is dominated by either a single mode and its harmonics or by broadband effects if turbulence develops. In this study we increase the centrifugal Rayleigh number progressively and investigate mode interactions during the vacillation regime which eventually lead to chaotic motion. Diogo B. Pitz acknowledges the financial support from the Capes foundation through the Science without Borders program.

  20. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    25, 26, 27, 28 February and 1st March from 11.00 to 12.00 hrs - Auditorium, bldg. 500 LECTURE SERIES Neutrino masses and oscillations by A. de Rujula / CERN-TH This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos. Academic Training Françoise Benz Secretariat Tel. 73127 francoise.benz@cern.ch

  1. A numerical study on buoyancy-driven flow in an inclined square enclosure heated and cooled on adjacent walls

    International Nuclear Information System (INIS)

    Aydin, O.; Uenal, A.; Ayhan, T.

    1999-01-01

    Buoyancy-driven flows in enclosures play a vital role in many engineering applications such as double glazing, ventilation of rooms, nuclear reactor insulation, solar energy collection, cooling of electronic components, and crystal growth in liquids. Here, numerical study on buoyancy-driven laminar flow in an inclined square enclosure heated from one side and cooled from the adjacent side is conducted using finite difference methods. The effect of inclination angle on fluid flow and heat transfer is investigated by varying the angle of inclination between 0 degree and 360degree, and the results are presented in the form of streamlines and isotherms for different inclination angles and Rayleigh numbers. On the basis of the numerical data, the authors determine the critical values of the inclination angle at which the rate of the transfer within the enclosure is either maximum or minimum

  2. Characteristics of buoyancy force on stagnation point flow with magneto-nanoparticles and zero mass flux condition

    Directory of Open Access Journals (Sweden)

    Iftikhar Uddin

    2018-03-01

    Full Text Available This attempt dedicated to the solution of buoyancy effect over a stretching sheet in existence of MHD stagnation point flow with convective boundary conditions. Thermophoresis and Brownian motion aspects are included. Incompressible fluid is electrically conducted in the presence of varying magnetic field. Boundary layer analysis is used to develop the mathematical formulation. Zero mass flux condition is considered at the boundary. Non-linear ordinary differential system of equations is constructed by means of proper transformations. Interval of convergence via numerical data and plots are developed. Characteristics of involved variables on the velocity, temperature and concentration distributions are sketched and discussed. Features of correlated parameters on Cf and Nu are examined by means of tables. It is found that buoyancy ratio and magnetic parameters increase and reduce the velocity field. Further opposite feature is noticed for higher values of thermophoresis and Brownian motion parameters on concentration distribution. Keywords: Stagnation point, MHD, Nanoparticles, Zero mass flux condition

  3. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    Energy Technology Data Exchange (ETDEWEB)

    Hu, L.H., E-mail: hlh@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huo, R.; Yang, D. [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  4. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow.

    Science.gov (United States)

    Hu, L H; Huo, R; Yang, D

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons--a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  5. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    International Nuclear Information System (INIS)

    Hu, L.H.; Huo, R.; Yang, D.

    2009-01-01

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  6. Numerical investigations of buoyancy-driven natural ventilation in a simple three-storey atrium building and thermal comfort evaluation

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2013-01-01

    The numerical investigations of buoyancy-driven natural ventilation and thermal comfort evaluation in a simple three-storey atrium building as a part of the passive ventilation strategy was undertaken using a validated Computational Fluid Dynamic (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modeling approach with the SST-k–ω turbulence model and the discrete transfer radiation model (DTRM) was used for the numerical investigations. The steady-state governing equations were solved using a commercial solver FLUENT©. Various flow situations of the buoyancy-driven natural ventilation in the building during day and night time were examined. The numerical results obtained for the airflow rates, airflow patterns and temperature distributions inside the building are presented in this paper. Using the numerical results, the well-known thermal comfort indices PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for the evaluation of the thermal comfort conditions in the occupied regions of the building. It was noticed that thermal conditions prevailing in the occupied areas of the building as a result of using the buoyancy-driven ventilation were mostly in comfort zone. From the study of the night time ventilation, it was found that hot water (80 °C) circulation (heated by solar collectors during daytime) along the chimney walls during night time and heat sources present in the building can be useful in inducing night ventilation airflows in the building as a part of the passive ventilation strategy. -- Highlights: • A simple three-storey atrium building. • Numerical modeling of buoyancy-driven ventilation flow in the building. • Effect of solar intensity and geographical location on ventilation. • CFD predictions were used to calculate thermal comfort indices. • Evaluation of thermal comfort conditions for the occupants

  7. Probing student reasoning approaches through the lens of dual-process theories: A case study in buoyancy

    Science.gov (United States)

    Gette, Cody R.; Kryjevskaia, Mila; Stetzer, MacKenzie R.; Heron, Paula R. L.

    2018-06-01

    A growing body of scholarly work indicates that student performance on physics problems stems from many factors, including relevant conceptual understanding. However, in contexts in which significant conceptual difficulties have been documented via research, it can be difficult to pinpoint and isolate such factors because students' written and interview responses rarely reveal the full richness of their conscious and, perhaps more importantly, subconscious reasoning paths. In this investigation, informed by dual-process theories of reasoning and decision making as well as the theoretical construct of accessibility, we conducted a series of experiments in order to gain greater insight into the factors impacting student performance on the "five-block problem," which has been used in the literature to probe student thinking about buoyancy. In particular, we examined both the impact of problem design (including salient features and cueing) and the impact of targeted instruction focused on density-based arguments for sinking and floating and on neutral buoyancy. The investigation found that instructional modifications designed to remove the strong intuitive appeal of the first-available response led to significantly improved performance, without improving student conceptual understanding of the requisite buoyancy concepts. As such, our findings represent an important first step in identifying systematic strategies for using theories from cognitive science to guide the development and refinement of research-based instructional materials.

  8. Effects of buoyancy and thermal radiation on MHD flow over a stretching porous sheet using homotopy analysis method

    Directory of Open Access Journals (Sweden)

    Yahaya Shagaiya Daniel

    2015-09-01

    Full Text Available This paper investigates the theoretical influence of buoyancy and thermal radiation on MHD flow over a stretching porous sheet. The model which constituted highly nonlinear governing equations is transformed using similarity solution and then solved using homotopy analysis method (HAM. The analysis is carried out up to the 5th order of approximation and the influences of different physical parameters such as Prandtl number, Grashof number, suction/injection parameter, thermal radiation parameter and heat generation/absorption coefficient and also Hartman number on dimensionless velocity, temperature and the rate of heat transfer are investigated and discussed quantitatively with the aid of graphs. Numerical results obtained are compared with the previous results published in the literature and are found to be in good agreement. It was found that when the buoyancy parameter and the fluid velocity increase, the thermal boundary layer decreases. In case of the thermal radiation, increasing the thermal radiation parameter produces significant increases in the thermal conditions of the fluid temperature which cause more fluid in the boundary layer due to buoyancy effect, causing the velocity in the fluid to increase. The hydrodynamic boundary layer and thermal boundary layer thickness increase as a result of increase in radiation.

  9. Probing student reasoning approaches through the lens of dual-process theories: A case study in buoyancy

    Directory of Open Access Journals (Sweden)

    Cody R. Gette

    2018-03-01

    Full Text Available A growing body of scholarly work indicates that student performance on physics problems stems from many factors, including relevant conceptual understanding. However, in contexts in which significant conceptual difficulties have been documented via research, it can be difficult to pinpoint and isolate such factors because students’ written and interview responses rarely reveal the full richness of their conscious and, perhaps more importantly, subconscious reasoning paths. In this investigation, informed by dual-process theories of reasoning and decision making as well as the theoretical construct of accessibility, we conducted a series of experiments in order to gain greater insight into the factors impacting student performance on the “five-block problem,” which has been used in the literature to probe student thinking about buoyancy. In particular, we examined both the impact of problem design (including salient features and cueing and the impact of targeted instruction focused on density-based arguments for sinking and floating and on neutral buoyancy. The investigation found that instructional modifications designed to remove the strong intuitive appeal of the first-available response led to significantly improved performance, without improving student conceptual understanding of the requisite buoyancy concepts. As such, our findings represent an important first step in identifying systematic strategies for using theories from cognitive science to guide the development and refinement of research-based instructional materials.

  10. Emotional Intelligence, Academic Procrastination and Academic ...

    African Journals Online (AJOL)

    Itwas therefore recommended that efforts should be made to look into other pressing factors like self-esteem, teacher's attitude, student's attitude, parental background among others which may be influencing student's poor academic achievement. Key words: Emotional Intelligence, Academic Procrastination, Academic ...

  11. Influence of various aspects of low Reynolds number k-ε turbulence models on predicting in-tube buoyancy affected heat transfer to supercritical pressure fluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chen-Ru; Zhang, Zhen [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Jiang, Pei-Xue, E-mail: jiangpx@tsinghua.edu.cn [Beijing Key Laboratory of CO_2 Utilization and Reduction Technology/Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Bo, Han-Liang [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China)

    2017-03-15

    Highlights: • Understanding of the mechanism of buoyancy effect on supercritical heat transfer. • Turbulence related parameters in upward and downward flows were compared. • Turbulent Prandtl number affected the prediction insignificantly. • Buoyancy production was insignificant compared with shear production. • Damping function had the greatest effect and is a priority for further modification. - Abstract: Heat transfer to supercritical pressure fluids was modeled for normal and buoyancy affected conditions using several low Reynolds number k-ε models, including the Launder and Sharma, Myong and Kasagi, and Abe, Kondoh and Nagano, with the predictions compared with experimental data. All three turbulence models accurately predicted the cases without heat transfer deterioration, but failed to accurately predict the cases with heat transfer deterioration although the general trends were captured, indicating that further improvements and modifications are needed for the low Reynolds number k-ε turbulence models to better predict buoyancy deteriorated heat transfer. Further investigations studied the influence of various aspects of the low Reynolds number k-ε turbulence models, including the turbulent Prandtl number, the buoyancy production of turbulent kinetic energy, and the damping function to provide guidelines for model development to more precisely predict buoyancy affected heat transfer. The results show that the turbulent Prandtl number and the buoyancy production of turbulent kinetic energy have little influence on the predictions for cases in this study, while new damping functions with carefully selected control parameters are needed in the low Reynolds number k-ε turbulence models to correctly predict the buoyancy effect for heat transfer simulations in various applications such as supercritical pressure steam generators (SPSGs) in the high temperature gas cooled reactor (HTR) and the supercritical pressure water reactor (SCWR).

  12. Influence of various aspects of low Reynolds number k-ε turbulence models on predicting in-tube buoyancy affected heat transfer to supercritical pressure fluids

    International Nuclear Information System (INIS)

    Zhao, Chen-Ru; Zhang, Zhen; Jiang, Pei-Xue; Bo, Han-Liang

    2017-01-01

    Highlights: • Understanding of the mechanism of buoyancy effect on supercritical heat transfer. • Turbulence related parameters in upward and downward flows were compared. • Turbulent Prandtl number affected the prediction insignificantly. • Buoyancy production was insignificant compared with shear production. • Damping function had the greatest effect and is a priority for further modification. - Abstract: Heat transfer to supercritical pressure fluids was modeled for normal and buoyancy affected conditions using several low Reynolds number k-ε models, including the Launder and Sharma, Myong and Kasagi, and Abe, Kondoh and Nagano, with the predictions compared with experimental data. All three turbulence models accurately predicted the cases without heat transfer deterioration, but failed to accurately predict the cases with heat transfer deterioration although the general trends were captured, indicating that further improvements and modifications are needed for the low Reynolds number k-ε turbulence models to better predict buoyancy deteriorated heat transfer. Further investigations studied the influence of various aspects of the low Reynolds number k-ε turbulence models, including the turbulent Prandtl number, the buoyancy production of turbulent kinetic energy, and the damping function to provide guidelines for model development to more precisely predict buoyancy affected heat transfer. The results show that the turbulent Prandtl number and the buoyancy production of turbulent kinetic energy have little influence on the predictions for cases in this study, while new damping functions with carefully selected control parameters are needed in the low Reynolds number k-ε turbulence models to correctly predict the buoyancy effect for heat transfer simulations in various applications such as supercritical pressure steam generators (SPSGs) in the high temperature gas cooled reactor (HTR) and the supercritical pressure water reactor (SCWR).

  13. Large Eddy simulation of turbulence: A subgrid scale model including shear, vorticity, rotation, and buoyancy

    Science.gov (United States)

    Canuto, V. M.

    1994-01-01

    The Reynolds numbers that characterize geophysical and astrophysical turbulence (Re approximately equals 10(exp 8) for the planetary boundary layer and Re approximately equals 10(exp 14) for the Sun's interior) are too large to allow a direct numerical simulation (DNS) of the fundamental Navier-Stokes and temperature equations. In fact, the spatial number of grid points N approximately Re(exp 9/4) exceeds the computational capability of today's supercomputers. Alternative treatments are the ensemble-time average approach, and/or the volume average approach. Since the first method (Reynolds stress approach) is largely analytical, the resulting turbulence equations entail manageable computational requirements and can thus be linked to a stellar evolutionary code or, in the geophysical case, to general circulation models. In the volume average approach, one carries out a large eddy simulation (LES) which resolves numerically the largest scales, while the unresolved scales must be treated theoretically with a subgrid scale model (SGS). Contrary to the ensemble average approach, the LES+SGS approach has considerable computational requirements. Even if this prevents (for the time being) a LES+SGS model to be linked to stellar or geophysical codes, it is still of the greatest relevance as an 'experimental tool' to be used, inter alia, to improve the parameterizations needed in the ensemble average approach. Such a methodology has been successfully adopted in studies of the convective planetary boundary layer. Experienc e with the LES+SGS approach from different fields has shown that its reliability depends on the healthiness of the SGS model for numerical stability as well as for physical completeness. At present, the most widely used SGS model, the Smagorinsky model, accounts for the effect of the shear induced by the large resolved scales on the unresolved scales but does not account for the effects of buoyancy, anisotropy, rotation, and stable stratification. The

  14. Academic detailing.

    Science.gov (United States)

    Shankar, P R; Jha, N; Piryani, R M; Bajracharya, O; Shrestha, R; Thapa, H S

    2010-01-01

    There are a number of sources available to prescribers to stay up to date about medicines. Prescribers in rural areas in developing countries however, may not able to access some of them. Interventions to improve prescribing can be educational, managerial, and regulatory or use a mix of strategies. Detailing by the pharmaceutical industry is widespread. Academic detailing (AD) has been classically seen as a form of continuing medical education in which a trained health professional such as a physician or pharmacist visits physicians in their offices to provide evidence-based information. Face-to-face sessions, preferably on an individual basis, clear educational and behavioural objectives, establishing credibility with respect to objectivity, stimulating physician interaction, use of concise graphic educational materials, highlighting key messages, and when possible, providing positive reinforcement of improved practices in follow-up visits can increase success of AD initiatives. AD is common in developed countries and certain examples have been cited in this review. In developing countries the authors have come across reports of AD in Pakistan, Sudan, Argentina and Uruguay, Bihar state in India, Zambia, Cuba, Indonesia and Mexico. AD had a consistent, small but potentially significant impact on prescribing practices. AD has much less resources at its command compared to the efforts by the industry. Steps have to be taken to formally start AD in Nepal and there may be specific hindering factors similar to those in other developing nations.

  15. Preliminary experimentally-validated forced and mixed convection computational simulations of the Rotatable Buoyancy Tunnel

    International Nuclear Information System (INIS)

    Clifford, Corey E.; Kimber, Mark L.

    2015-01-01

    Although computational fluid dynamics (CFD) has not been directly utilized to perform safety analyses of nuclear reactors in the United States, several vendors are considering adopting commercial numerical packages for current and future projects. To ensure the accuracy of these computational models, it is imperative to validate the assumptions and approximations built into commercial CFD codes against physical data from flows analogous to those in modern nuclear reactors. To this end, researchers at Utah State University (USU) have constructed the Rotatable Buoyancy Tunnel (RoBuT) test facility, which is designed to provide flow and thermal validation data for CFD simulations of forced and mixed convection scenarios. In order to evaluate the ability of current CFD codes to capture the complex physics associated with these types of flows, a computational model of the RoBuT test facility is created using the ANSYS Fluent commercial CFD code. The numerical RoBuT model is analyzed at identical conditions to several experimental trials undertaken at USU. Each experiment is reconstructed numerically and evaluated with the second-order Reynolds stress model (RSM). Two different thermal boundary conditions at the heated surface of the RoBuT test section are investigated: constant temperature (isothermal) and constant surface heat flux (isoflux). Additionally, the fluid velocity at the inlet of the test section is varied in an effort to modify the relative importance of natural convection heat transfer from the heated wall of the RoBuT. Mean velocity, both in the streamwise and transverse directions, as well as components of the Reynolds stress tensor at three points downstream of the RoBuT test section inlet are compared to results obtained from experimental trials. Early computational results obtained from this research initiative are in good agreement with experimental data obtained from the RoBuT facility and both the experimental data and numerical method can be used

  16. An analysis of the effect of buoyancy on phase distribution phenomena

    International Nuclear Information System (INIS)

    Maneesh Singhal; Richard T Lahey Jr

    2005-01-01

    Full text of publication follows: It is well known that pronounced lateral phase distributions may occur in two-phase conduit flows. Moreover, the lateral phase distribution appears to strongly influenced by the buoyancy of the dispersed phase. This study used a state-of-the-art two-fluid model, having no arbitrary coefficients, to predict steady, fully developed phase distribution in pipe flows. In particular, bubbly up-flows and down-flows in pipes, and slurry up-flows in pipes, having positive, negative and neutral buoyant particles, were analyzed and compared against appropriate terrestrial (1 g) data. In addition, microgravity bubbly flow data were also analyzed using the same two-fluid model. It was found that this two-fluid model was able to predict these data sets, including detailed predictions of the measured phasic velocity, dispersed phase volume fraction and turbulence (i.e., turbulent kinetic energy and Reynolds stress) fields. It was also found that the numerical algorithm, which was developed and used to evaluate the two-fluid model, was extremely efficient and could be easily run on a small PC. These results clearly demonstrate that a properly formulated two-fluid model, using mechanistically-based closure laws, can predict a wide range of multidimensional multiphase flow data without the need for 'tuners' and empirical correlations. Moreover, it appears that this approach can be used to develop and/or assess other flow-regime-specific closure laws for use in computational multiphase fluid dynamic (CMFD) solvers of transient two-fluid models, which, in turn, can be used for the design and analysis of various industrially important multiphase systems and processes. (authors)

  17. Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Nikolaos Kokkos

    2016-04-01

    Full Text Available A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively. Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island, depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1, tending to destroy surface meso-scale eddies.

  18. Buoyancy effects in overcooling transients calculated for the NRC pressurized thermal shock study

    International Nuclear Information System (INIS)

    Theofanous, T.G.; Iyer, K.; Nourbakhsh, H.P.; Gherson, P.

    1986-05-01

    The thermal-hydraulic responses of three PWRs (Oconee, Calvert Cliffs, and H.B. Robinson), to postulated Pressurized Thermal Shock (PTS) scenarios, which were originally determined by RELAP5 and TRAC calculations, are being further developed here with regard to buoyancy/stratification effects. These three PWRs were the subject of the NRC PTS study, and the present results helped define the thermal-hydraulic conditions utilized in the fracture mechanics calculations carried out at ORNL. The computer program REMIX, which is based on the Regional Mixing Model (RMM), was the analytical tool employed, while Purdue's 1/2-Scale HPI Thermal Mixing facility provided the basis for experimental support. Important mixing and wall heat transfer regimes are delineated on the basis of these results. We conclude that stratification is important only in cases of complete loop stagnation and that mixed-convection effects are important for downcomer flow velocities below approx.0.25 m/s. The stratification is small in magnitude, however it is important in creating a recirculating flow pattern which activates the lower plenum, pump and loop seal volumes, to participate in the mixing process. This mixing process together with the heat input from the wall metal significantly impact the cooldown rates. Heat transfer in the plume region is dominated by forced convection. On the other hand, the presence of the Reactor Pressure Vessel (RPV) wall cladding and wall conduction significantly dampen the free convection effects in the low velocity, mixed-convection, regime. For the stagnant loop cases, all locations outside the plume region are included in this regime. In the presence of natural loop circulation and a uniformly distributed downcomer flow, the mixed convection regime is also expected, however, the forced convection regime can also be observed in highly asymmetric flow behavior

  19. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    24, 25, 26 April LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Anti-Matter by R. LANDUA /CERN-EP Antiparticles are a crucial ingredient of particle physics and cosmology. More than 70 years after Dirac's bold prediction and the subsequent discovery of the positron in 1932, antiparticles are still in the spotlight of modern physics. This lecture for non-specialists will start with a theoretical and historical introduction. Why are antiparticles needed? Why is the (CPT) symmetry between particles and antiparticles so fundamental? What is their role in cosmology? The second part will give an overview about the many aspects of antiparticles in experimental physics: as a tool in accelerators; as a probe inside atoms or nuclei; or as an object to study fundamental symmetries. In the third part, the lecture will focus on the experimental 'antimatter' programme at the Antiproton Decelerator (AD), with special emphysis on antihydrogen production and spectroscopy. The lecture will conclude with an outl...

  20. CEO age and gender: Subsequent market performance

    Directory of Open Access Journals (Sweden)

    Marcelo Eduardo

    2016-12-01

    Full Text Available The issue of CEO age and gender vs. concurrent performance is extensively examined, but the association with subsequent performance has limited treatment in the financial literature, and with conflicting findings. In the current study, we examine the association between CEO age and gender, and subsequent company market performance using a more recent set of observations and the standard four-factor model to estimate future cumulative abnormal shareholder returns. We find that subsequent abnormal shareholder returns are marginally significantly higher for female CEOs than for their male counterparts, but no material pattern is observed between CEO age and subsequent abnormal shareholder return performance.

  1. Silicate melts density, buoyancy relations and the dynamics of magmatic processes in the upper mantle

    Science.gov (United States)

    Sanchez-Valle, Carmen; Malfait, Wim J.

    2016-04-01

    with results from ab initio calculations. The density model has been applied to examine the mineral-melt buoyancy relations at depth and the implications of these results for the dynamics of magma chambers, crystal settling and the stability and mobility of magmas in the upper mantle will be discussed.

  2. Anisotropy and buoyancy in nuclear turbulent heat transfer - critical assessment and needs for modelling

    International Nuclear Information System (INIS)

    Groetzbach, G.

    2007-12-01

    Computational Fluid Dynamics (CFD) programs have a wide application field in reactor technique, like to diverse flow types which have to be considered in Accelerator Driven nuclear reactor Systems (ADS). This requires turbulence models for the momentum and heat transfer with very different capabilities. The physical demands on the models are elaborated for selected transport mechanisms, the status quo of the modelling is discussed, and it is investigated which capabilities are offered by the market dominating commercial CFD codes. One topic of the discussion is on the already earlier achieved knowledge on the distinct anisotropy of the turbulent momentum and heat transport near walls. It is shown that this is relevant in channel flows with inhomogeneous wall conditions. The related consequences for the turbulence modelling are discussed. The second topic is the turbulent heat transport in buoyancy influenced flows. The only turbulence model for heat transfer which is available in the large commercial CFD-codes is based on the Reynolds analogy. This means, it is required to prescribe suitable turbulent Prandtl number distributions. There exist many correlations for channel flows, but they are seldom used in practical applications. Here, a correlation is deduced for the local turbulent Prandtl number which accounts for many parameters, like wall distance, molecular Prandtl number of the fluid, wall roughness and local shear stress, thermal wall condition, etc. so that it can be applied to most ADS typical heat transporting channel flows. The spatial dependence is discussed. It is shown that it is essential for reliable temperature calculations to get accurate turbulent Prandtl numbers especially near walls. If thermal wall functions are applied, then the correlation for the turbulent Prandtl number has to be consistent with the wall functions to avoid unphysical discretisation dependences. In using Direct Numerical Simulation (DNS) data for horizontal fluid layers it

  3. Monitoring International Interest in Transnational Academic Mobility to Australia

    Science.gov (United States)

    Hopkins, John L.

    2011-01-01

    This research examines the issue of transnational academic mobility of academic staff looking at potential moves to higher education institutions in Australia. By establishing a web-based portal, attracting interested parties from around the world with information about Australian universities and subsequent career opportunities, web analytics are…

  4. Malaysian University Students' Attitudes to Academic Dishonesty and Business Ethics

    Science.gov (United States)

    Ahmad, Zauwiyah; Simun, Maimun; Mohammad, Junaini

    2008-01-01

    Academic dishonesty is believed to have predictive ability for subsequent behaviours in the workplace. This study adds to the literature by investigating Malaysian business students' attitudes to academic dishonesty and their attitudes to ethics issues in business. This study also explores the association between these two constructs. The form of…

  5. Influence of the weighing bar size to determine optimal time of biodiesel-glycerol separation by using the buoyancy weighing-bar method

    Science.gov (United States)

    Tambun, R.; Sibagariang, Y.; Manurung, J.

    2018-02-01

    The buoyancy weighing-bar method is a novel method in the particle size distribution measurement. This method can measure particle size distributions of the settling particles and floating particles. In this study, the buoyancy weighing-bar method is applied to determine optimal time of biodiesel-glycerol separation. The buoyancy weighing-bar method can be applied to determine the separation time because biodiesel and glycerol have the different densities. The influences of diameter of weighing-bar by using the buoyancy weighing-bar method would be experimentally investigated. The diameters of weighing-bar in this experiment are 8 mm, 10 mm, 15 mm and 20 mm, while the graduated cylinder (diameter : 65 mm) is used as vessel. The samples used in this experiment are the mixture of 95 % of biodiesel and 5 % of glycerol. The data obtained by the buoyancy weighing-bar method are analized by using the gas chromatography to determine the purity of biodiesel. Based on the data obtained, the buoyancy weighing-bar method can be used to detect the separation time of biodiesel-glycerol by using the weighing-bar diameter of 8 mm, 10 mm, 15 mm and 20 mm, but the most accuracy in determination the biodiesel-glycerol separation time is obtained by using the weighing-bar diameter of 20 mm. The biodiesel purity of 97.97 % could be detected at 64 minutes by using the buoyancy weighing-bar method when the weighing-bar diameter of 20 mm is used.

  6. Coupled thermo-capillary and buoyancy convection in a liquid layer locally heated on its free surface

    International Nuclear Information System (INIS)

    Favre, E.

    1997-01-01

    Coupled buoyancy and thermo-capillary convection lead to a convective motion of the interface liquid/gas, which changes drastically the heat and mass transfer across the liquid layer. Two experiments are considered, depending on the fluid: oil or mercury. The liquid is set in a cooled cylindrical vessel, and heated by a heat flux across the center of the free surface. The basic flow, in the case of oil, is a torus. When the heat parameter increases, a stationary flow looking like petals or rays appears when the aspect ratio length/depth is small, and like concentric rings in the case of large values of the aspect ratio. The lateral confinement selects the azimuthal length wave. In the case of petals-like flow, a sub-critical Hopf bifurcation is underlined. The turbulence is found to be 'weak', even for the largest values of the Marangoni number (Ma ≅ 1.3 * 10 5 ). In the case of mercury, the thermo-capillary effect is reduced to zero, due to impurities at the surface, which have special trajectories we describe and compare to a simpler experiment. The only buoyancy forces induces an un-stationary, weakly turbulent flow as soon as the heating power exceeds 4 W (≅ 4.5 * 10 3 , calculated with h = 1 mm). The last part concerns the analysis of the effect on the flow of the boundary conditions, the geometry, the Prandtl number, the buoyancy force, with the help of the literature. Results concerning heat transfer, especially the exponent of the law Nusselt number vs. heating power, are compared with available data. (author) [fr

  7. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Z.; Chin, Y.S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  8. Simulation of buoyancy induced gas mixing tests performed in a large scale containment facility using GOTHIC code

    International Nuclear Information System (INIS)

    Liang, Z.; Chin, Y.S.

    2014-01-01

    This paper compares containment thermal-hydraulics simulations performed using GOTHIC against a past test set of large scale buoyancy induced helium-air-steam mixing experiments that had been performed at the AECL's Chalk River Laboratories. A number of typical post-accident containment phenomena, including thermal/gas stratification, natural convection, cool air entrainment, steam condensation on concrete walls and active local air cooler, were covered. The results provide useful insights into hydrogen gas mixing behaviour following a loss-of-coolant accident and demonstrate GOTHIC's capability in simulating these phenomena. (author)

  9. Spatio-temporal variability in western Baltic cod early life stage survival mediated by egg buoyancy, hydrography and hydrodynamics

    DEFF Research Database (Denmark)

    Hinrichsen, H-H.; Hüssy, K.; Huwer, B.

    2012-01-01

    Spatio-temporal variability in western Baltic cod early life stage survival mediated by egg buoyancy, hydrography and hydrodynamics. – ICES Journal of Marine Science, 69: 1744–1752.To disentangle the effects of different drivers on recruitment variability of marine fish, a spatially and temporally...... explicit understanding of both the spawning stock size and the early life stage dynamics is required. The objectives of this study are to assess the transport of western Baltic cod early life stages as well as the variability in environmentally-mediated survival along drift routes in relation to both...

  10. Buoyancy-driven instability in a vertical cylinder: Binary fluids with Soret effect. I - General theory and stationary stability results

    Science.gov (United States)

    Hardin, G. R.; Sani, R. L.; Henry, D.; Roux, B.

    1990-01-01

    The buoyancy-driven instability of a monocomponent or binary fluid completely contained in a vertical circular cylinder is investigated, including the influence of the Soret effect for the binary mixture. The Boussinesq approximation is used, and the resulting linear stability problem is solved using a Galerkin technique. The analysis considers fluid mixtures ranging from gases to liquid metals. The flow structure is found to depend strongly on both the cylinder aspect ratio and the magnitude of the Soret effect. The predicted stability limits are shown to agree closely with experimental observations.

  11. Baculite 3D Modeling: a New Method for Computing Buoyancy, Stability, and Orientation with Implications for Ectocochleate Cephalopod Hydrostatics

    Science.gov (United States)

    Peterman, D. J.; Barton, C. C.

    2017-12-01

    Ectocochleate (external) cephalopod shells are comprised of a body chamber which houses the organism's soft parts and the phragmocone which consists of a series of progressively larger chambers (camerae) divided by septa. The phragmocone is used as a passive gas float for buoyancy regulation. The soft body and the mineralized shell are denser than water and are negatively buoyant while the phragmocone is positively buoyant due to some fraction of gas in its chambers. This provides a neutrally buoyant condition when the total mass of the organism is equal to the mass of the displaced water. The static orientation of the organism occurs when the centers of buoyancy and mass are vertically aligned and stability is determined by their degree of separation. Three-dimensional modeling of a specimen of Baculites compressus (which has a straight conical shell) was performed using Autodesk Meshmixer, Netfabb ®, Blender 2.78, and MeshLab. The initial 3D mesh shapefile was created by Autodesk ReCap 360™ photogrammetry software. The specimen requirements for the models include: an external shell (ideally complete, otherwise approximated), a septum showing lower order frilling, and a suture pattern to reconstruct the higher order septal frilling (for complex septa). Volumes and centers of mass/buoyancy were calculated with MeshLab in order to determine neutrality, stability, and orientation. Our method can be used to investigate the influence of morphological features on these hydrostatic properties of ectocochleate cephalopods and also the paleoecological implications of different morphotypes. Baculites compressus, is found to assume relatively stable vertical orientations when the shell is positively or neutrally buoyant. By arbitrarily flooding all chambers, the ammonite becomes negatively buoyant, and the centers of buoyancy and mass virtually coincide. This reduces stability but allows the living ammonite to assume a larger range of orientations, including horizontal

  12. Subsequent pregnancy outcome after previous foetal death

    NARCIS (Netherlands)

    Nijkamp, J. W.; Korteweg, F. J.; Holm, J. P.; Timmer, A.; Erwich, J. J. H. M.; van Pampus, M. G.

    Objective: A history of foetal death is a risk factor for complications and foetal death in subsequent pregnancies as most previous risk factors remain present and an underlying cause of death may recur. The purpose of this study was to evaluate subsequent pregnancy outcome after foetal death and to

  13. Wildland fire limits subsequent fire occurrence

    Science.gov (United States)

    Sean A. Parks; Carol Miller; Lisa M. Holsinger; Scott Baggett; Benjamin J. Bird

    2016-01-01

    Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence...

  14. A Review of Subsequence Time Series Clustering

    Directory of Open Access Journals (Sweden)

    Seyedjamal Zolhavarieh

    2014-01-01

    Full Text Available Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies.

  15. A review of subsequence time series clustering.

    Science.gov (United States)

    Zolhavarieh, Seyedjamal; Aghabozorgi, Saeed; Teh, Ying Wah

    2014-01-01

    Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies.

  16. A Review of Subsequence Time Series Clustering

    Science.gov (United States)

    Teh, Ying Wah

    2014-01-01

    Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies. PMID:25140332

  17. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson

    2012-11-01

    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  18. The academic rewards of socially-oriented happiness: Interdependent happiness promotes academic engagement.

    Science.gov (United States)

    Datu, Jesus Alfonso D; King, Ronnel B; Valdez, Jana Patricia M

    2017-04-01

    Interdependent happiness has been found to be positively associated with optimal psychological outcomes in collectivist cultures. However, the association between interdependent happiness and key academic outcomes has remained unexplored. The current study examined the association of interdependent happiness with key academic outcomes such as autonomous motivation, engagement, and achievement using both cross-sectional (Study 1) and longitudinal (Study 2) approaches. Study 1 revealed that interdependent happiness positively predicted academic engagement (partly) via autonomous motivation. Study 2 showed that prior interdependent happiness positively predicted subsequent academic engagement even after controlling for autoregressor effects. In addition, reciprocal associations among the key variables were found. Taken together, results of the two studies suggest that interdependent happiness plays an adaptive role in the academic context especially in a collectivist cultural setting. Theoretical and practical implications are discussed. Copyright © 2016 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  19. Tritium sorption by cement and subsequent release

    International Nuclear Information System (INIS)

    Ono, F.; Tanaka, S.; Yamawaki, M.

    1994-01-01

    In a fusion reactor or tritium handling facilities, contamination of concrete by tritium and subsequent release from it to the reactor or experimental rooms is a matter of problem for safety control of tritium and management of operational environment. In order to evaluate these tritium behavior, interaction of tritiated water with concrete or cement should be clarified. In the present study, HTO sorption and subsequent release from cement were studied by combining various experimental methods. From the basic studies on tritium-cement interactions, it has become possible to evaluate tritium uptake by cement or concrete and subsequent tritium release behavior as well as tritium removing methods from them

  20. Three-dimensional computational fluid dynamics analysis of buoyancy-driven natural ventilation and entropy generation in a prismatic greenhouse

    Directory of Open Access Journals (Sweden)

    Aich Walid

    2018-01-01

    Full Text Available A computational analysis of the natural ventilation process and entropy generation in 3-D prismatic greenhouse was performed using CFD. The aim of the study is to investigate how buoyancy forces influence air-flow and temperature patterns inside the greenhouse having lower level opening in its right heated façade and also upper level opening near the roof top in the opposite cooled façade. The bot-tom and all other walls are assumed to be perfect thermal insulators. Rayleigh number is the main parameter which changes from 103 to 106 and Prandtl number is fixed at Pr = 0.71. Results are reported in terms of particles trajectories, iso-surfaces of temperature, mean Nusselt number, and entropy generation. It has been found that the flow structure is sensitive to the value of Rayleigh number and that heat transfer increases with increasing this parameter. Also, it have been noticed that, using asymmetric opening positions improve the natural ventilation and facilitate the occurrence of buoyancy induced upward cross air-flow (low-level supply and upper-level extraction inside the greenhouse.

  1. Numerical Investigation of Heat Transfer with Thermal Radiation in an Enclosure in Case of Buoyancy Driven Flow

    Directory of Open Access Journals (Sweden)

    Christoph Hochenauer

    2014-08-01

    Full Text Available The purpose of this paper is to investigate state of the art approaches and their accuracy to compute heat transfer including radiation inside a closed cavity whereas buoyancy is the only driving force. This research is the first step of an all-embracing study dealing with underhood airflow and thermal management of vehicles. Computational fluid dynamic (CFD simulation results of buoyancy driven flow inside a simplified engine compartment are compared to experimentally gained values. The test rig imitates idle condition without any working fan. Thus, the airflow is only driven by natural convection. A conventional method used for these applications is to compute the convective heat transfer coefficient and air temperature using CFD and calculate the wall temperature separately by performing a thermal analysis. The final solution results from coupling two different software tools. In this paper thermal conditions inside the enclosure are computed by the use of CFD only. The impact of the turbulence model as well as the results of various radiation models are analyzed and compared to the experimental data.

  2. Numerical investigation of double diffusive buoyancy forces induced natural convection in a cavity partially heated and cooled from sidewalls

    Directory of Open Access Journals (Sweden)

    Rasoul Nikbakhti

    2016-03-01

    Full Text Available This paper deals with a numerical investigation of double-diffusive natural convective heat and mass transfer in a cavity filled with Newtonian fluid. The active parts of two vertical walls of the cavity are maintained at fixed but different temperatures and concentrations, while the other two walls, as well as inactive areas of the sidewalls, are considered to be adiabatic and impermeable to mass transfer. The length of the thermally active part equals half of the height. The non-dimensional forms of governing transport equations that describe double-diffusive natural convection for two-dimensional incompressible flow are functions of temperature or energy, concentration, vorticity, and stream-function. The coupled differential equations are discretized via FDM (Finite Difference Method. The Successive-Over-Relaxation (SOR method is used in the solution of the stream function equation. The analysis has been done for an enclosure with different aspect ratios ranging from 0.5 to 11 for three different combinations of partially active sections. The results are presented graphically in terms of streamlines, isotherms and isoconcentrations. In addition, the heat and mass transfer rate in the cavity is measured in terms of the average Nusselt and Sherwood numbers for various parameters including thermal Grashof number, Lewis number, buoyancy ratio and aspect ratio. It is revealed that the placement order of partially thermally active walls and the buoyancy ratio influence significantly the flow pattern and the corresponding heat and mass transfer performance in the cavity.

  3. Magma reservoirs and neutral buoyancy zones on Venus - Implications for the formation and evolution of volcanic landforms

    Science.gov (United States)

    Head, James W.; Wilson, Lionel

    1992-01-01

    The production of magma reservoirs and neutral buoyancy zones (NBZs) on Venus and the implications of their development for the formation and evolution of volcanic landforms are examined. The high atmospheric pressure on Venus reduces volatile exsolution and generally serves to inhibit the formation of NBZs and shallow magma reservoirs. For a range of common terrestrial magma-volatile contents, magma ascending and erupting near or below mean planetary radius (MPR) should not stall at shallow magma reservoirs; such eruptions are characterized by relatively high total volumes and effusion rates. For the same range of volatile contents at 2 km above MPR, about half of the cases result in the direct ascent of magma to the surface and half in the production of neutral buoyancy zones. NBZs and shallow magma reservoirs begin to appear as gas content increases and are nominally shallower on Venus than on earth. For a fixed volatile content, NBZs become deeper with increasing elevation: over the range of elevations treated in this study (-1 km to +4.4 km) depths differ by a factor of 2-4. Factors that may account for the low height of volcanoes on Venus are discussed.

  4. Academic Entitlement and Academic Performance in Graduating Pharmacy Students

    OpenAIRE

    Jeffres, Meghan N.; Barclay, Sean M.; Stolte, Scott K.

    2014-01-01

    Objectives. To determine a measurable definition of academic entitlement, measure academic entitlement in graduating doctor of pharmacy (PharmD) students, and compare the academic performance between students identified as more or less academically entitled.

  5. Self-concept and academic achievement: a meta-analysis of longitudinal relations.

    Science.gov (United States)

    Huang, Chiungjung

    2011-10-01

    The relation between self-concept and academic achievement was examined in 39 independent and longitudinal samples through the integration of meta-analysis and path analysis procedures. For relations with more than 3 independent samples, the mean observed correlations ranged from .20 to .27 between prior self-concept and subsequent academic achievement and from .19 to .25 between prior academic achievement and subsequent self-concept. Globality/specificity of self-concept was the only significant moderating factor in the relation between (a) prior self-concept and subsequent academic achievement and (b) prior academic achievement and subsequent self-concept. As high self-concept is related to high academic performance and vice-versa, intervention programs that combine self-enhancement and skill development should be integrated. Copyright © 2011 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  6. Commercializing Academic Research

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Hussinger, Katrin; Schneider, Cédric

    2011-01-01

    the importance of academic patenting. Our findings suggest that academic involvement in patenting results in a citation premium, as academic patents appear to generate more forward citations. We also find that in the European context of changing research objectives and funding sources since the mid-1990s...

  7. The Academic Adviser

    Science.gov (United States)

    Darling, Ruth

    2015-01-01

    In this essay, I explore the idea that "academic" advisers are "academics" who play a major role in connecting the general education curriculum to the students' experience as well as connecting the faculty to the students' holistic experience of the curriculum. The National Academic Advising Association Concept of Academic…

  8. Investigation of buoyancy effects on turbulent nonpremixed jet flames by using normal and low-gravity conditions

    Science.gov (United States)

    Idicheria, Cherian Alex

    An experimental study was performed with the aim of investigating the structure of transitional and turbulent nonpremixed jet flames under different gravity conditions. In particular, the focus was to determine the effect of buoyancy on the mean and fluctuating characteristics of the jet flames. Experiments were conducted under three gravity levels, viz. 1 g, 20 mg and 100 mug. The milligravity and microgravity conditions were achieved by dropping a jet-flame rig in the UT-Austin 1.25-second and the NASA-Glenn Research Center 2.2-second drop towers, respectively. The principal diagnostics employed were time-resolved, cinematographic imaging of the visible soot luminosity and planar laser Mie scattering (PLMS). For the cinematographic flame luminosity imaging experiments, the flames studied were piloted nonpremixed propane, ethylene and methane jet flames at source Reynolds numbers ranging from 2000 to 10500. From the soot luminosity images, mean and root-mean square (RMS) images were computed, and volume rendering of the image sequences was used to investigate the large-scale structure evolution and flame tip dynamics. The relative importance of buoyancy was quantified with the parameter, xL , as defined by Becker and Yamazaki [1978]. The results show, in contrast to previous microgravity studies, that the high Reynolds number flames have the same flame length irrespective of the gravity level. The RMS fluctuations and volume renderings indicate that the large-scale structure and flame tip dynamics are essentially identical to those of purely momentum driven flames provided xL is approximately less than 2. The volume-renderings show that the luminous structure celerities (normalized by jet exit velocity) are approximately constant for xL 8. The celerity values for xL > 8 are seen to follow a x3/2L scaling, which can be predicted with a simplified momentum equation analysis for the buoyancy-dominated regime. The underlying turbulent structure and mean mixture

  9. Academic Training: Academic Training Lectures-Questionnaire

    CERN Multimedia

    2004-01-01

    ACADEMIC TRAINING Françoise Benz tel. 73127 academic.training@cern.ch SUGGEST AND WIN! Its time to plan the 2004-2005 lecture series. From today until March 19 you have the chance to give your contribution to planning for next year's Academic Training Lecture Series. At the web site: http://cern.ch/Academic.Training/questionnaire you will find questionnaires proposing topics in high energy physics, applied physics and science and society. Answering the questionnaire will help ensure that the selected topics are as close as possible to your interests. In particular requests and comments from students will be much appreciated. To encourage your contribution, the AT Committee will reward one lucky winner with a small prize, a 50 CHF coupon for a book purchase at the CERN bookshop.

  10. Students' academic self-efficacy viz-a-viz their academic achievement

    African Journals Online (AJOL)

    Self-efficacy predicts academic achievement by influencing the effect of skills, previous experience, mental ability, or other self-beliefs on subsequent achievement. Students with high self-efficacy set challenging goals engage in more effective learning strategy use and persevere when encountered by difficult tasks.

  11. Embolisation of intracranial meningiomas without subsequent surgery

    International Nuclear Information System (INIS)

    Bendszus, M.; Solymosi, L.; Martin-Schrader, I.; Schlake, H.P.

    2003-01-01

    In an open, prospective study, we embolised intracranial meningiomas in seven patients, without subsequent surgery. Follow-up over a mean of 20 months included serial neurological examination, MRI and MR spectroscopy. Clinically, embolisation had no adverse effects. Symptomatic patients showed clinical improvement. On MRI marked tumour shrinkage occurred after embolisation in six patients, and was most pronounced during the first 6 months. In a young boy the tumour was unchanged despite complete angiographic devascularisation. Embolisation without subsequent surgery may cause substantial tumour shrinkage and thus be used in selected in patients. However, thorough follow-up is mandatory to ascertain the effects of embolisation. (orig.)

  12. Academic self-concept, autonomous academic motivation, and academic achievement : mediating and additive effects

    OpenAIRE

    Guay, Frédéric; Ratelle, Catherine; Roy, Amélie; Litalien, David

    2010-01-01

    Three conceptual models were tested to examine the relationships among academic self-concept, autonomous academic motivation, and academic achievement. This allowed us to determine whether 1) autonomous academic motivation mediates the relation between academic self-concept and achievement, 2) academic self-concept mediates the relation between autonomous academic motivation and achievement, or 3) both motivational constructs have an additive effect on academic achievement. A total of 925 hig...

  13. Buoyancy-driven mixing of fluids in a confined geometry; Melange gravitationnel de fluides en geometrie confinee

    Energy Technology Data Exchange (ETDEWEB)

    Hallez, Y

    2007-12-15

    The present work based on Direct Numerical Simulations is devoted to the study of mixing between two miscible fluids of different densities. The movement of these fluids is induced by buoyancy. Three geometries are considered: a cylindrical tube, a square channel and a plane two-dimensional flow. For cylindrical tubes, the results of numerical simulations fully confirm previous experimental findings by Seon et al., especially regarding the existence of three different flow regimes, depending on the tilt angle. The comparison of the various geometries shows that tridimensional flows in tubes or channels are similar, whereas the two-dimensional model fails to give reliable information about real 3D flows, either from a quantitative point of view or for a phenomenological understanding. A peculiar attention is put on a joint analysis of the concentration and vorticity fields and allows us to explain several subtle aspects of the mixing dynamics. (author)

  14. A weakly nonlinear model with exact coefficients for the fluttering and spiraling motions of buoyancy-driven bodies

    Science.gov (United States)

    Magnaudet, Jacques; Tchoufag, Joel; Fabre, David

    2015-11-01

    Gravity/buoyancy-driven bodies moving in a slightly viscous fluid frequently follow fluttering or helical paths. Current models of such systems are largely empirical and fail to predict several of the key features of their evolution, especially close to the onset of path instability. Using a weakly nonlinear expansion of the full set of governing equations, we derive a new generic reduced-order model of this class of phenomena based on a pair of amplitude equations with exact coefficients that drive the evolution of the first pair of unstable modes. We show that the predictions of this model for the style (eg. fluttering or spiraling) and characteristics (eg. frequency and maximum inclination angle) of path oscillations compare well with various recent data for both solid disks and air bubbles.

  15. Weakly Nonlinear Model with Exact Coefficients for the Fluttering and Spiraling Motion of Buoyancy-Driven Bodies

    Science.gov (United States)

    Tchoufag, Joël; Fabre, David; Magnaudet, Jacques

    2015-09-01

    Gravity- or buoyancy-driven bodies moving in a slightly viscous fluid frequently follow fluttering or helical paths. Current models of such systems are largely empirical and fail to predict several of the key features of their evolution, especially close to the onset of path instability. Here, using a weakly nonlinear expansion of the full set of governing equations, we present a new generic reduced-order model based on a pair of amplitude equations with exact coefficients that drive the evolution of the first pair of unstable modes. We show that the predictions of this model for the style (e.g., fluttering or spiraling) and characteristics (e.g., frequency and maximum inclination angle) of path oscillations compare well with various recent data for both solid disks and air bubbles.

  16. DNS of buoyancy-driven flows and Lagrangian particle tracking in a square cavity at high Rayleigh numbers

    International Nuclear Information System (INIS)

    Puragliesi, R.; Dehbi, A.; Leriche, E.; Soldati, A.; Deville, M.O.

    2011-01-01

    Highlights: → 2D study of micro-size particle depletion driven by chaotic natural convective flows in square domains. → Description of velocity and temperature first and second moments with changing in the Rayleigh number. → Strong decoupling between the turbulent kinetic energy and the dissipation rate. → Particle recirculation sustained by the vertical hot boundary layer. → Deposition mostly induced by gravity, thermophoretic and lift forces are negligible. - Abstract: In this work we investigate numerically particle deposition in the buoyancy driven flow of the differentially heated cavity (DHC). We consider two values of the Rayleigh number (Ra = 10 9 , 10 10 ) and three values of the particle diameter (d p = 15, 25, 35 [μm]). We consider the cavity filled with air and particles with the same density of water ρ w = 1000 [kg/m 3 ] (aerosol). We use direct numerical simulations (DNS) for the continuous phase, and we solve transient Navier-Stokes and energy transport equations written in an Eulerian framework, under the Boussinesq approximation, for the viscous incompressible Newtonian fluid with constant Prandtl number (Pr = 0.71). First- and second-order statistics are presented for the continuous phase as well as important quantities like turbulent kinetic energy (TKE) and temperature variance with the associated production and dissipation fields. The TKE production shows different behaviour at the two Rayleigh numbers. The Lagrangian approach has been chosen for the dispersed phase description. The forces taken into account are drag, gravity, buoyancy, lift and thermophoresis. A first incursion in the sedimentation mechanisms is presented. Current results indicate that the largest contribution to particle deposition is caused by gravitational settling, but a strong recirculating zone, which liftoffs and segregates particles, contributes to decrease settling. Deposition takes place mostly at the bottom wall. The influence of lift and thermophoretic

  17. DNS of buoyancy-driven flows and Lagrangian particle tracking in a square cavity at high Rayleigh numbers

    Energy Technology Data Exchange (ETDEWEB)

    Puragliesi, R., E-mail: riccardo.puragliesi@psi.ch [Nuclear Energy and Safety Research Department, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Laboratoire d' Ingenierie Numerique, Ecole Polytechnique Federale de Lausanne, Station 9, CH-1015 Lausanne (Switzerland); Dehbi, A., E-mail: abdel.dehbi@psi.ch [Nuclear Energy and Safety Research Department, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Leriche, E., E-mail: emmanuel.leriche@univ-st-etienne.fr [Universite de Lyon, F-42023 Saint-Etienne, LMFA-UJM St-Etienne, CNRS UMR 5509 Universite de St-Etienne, 23 rue Docteur Paul Michelon, F-42023 Saint-Etienne (France); Soldati, A., E-mail: soldati@uniud.it [Dipartimento di Energetica e Macchine, Universita di Udine, Via delle Scienze 208, IT-33100 Udine (Italy); Deville, M.O., E-mail: michel.deville@epfl.ch [Laboratoire d' Ingenierie Numerique, Ecole Polytechnique Federale de Lausanne, Station 9, CH-1015 Lausanne (Switzerland)

    2011-10-15

    Highlights: > 2D study of micro-size particle depletion driven by chaotic natural convective flows in square domains. > Description of velocity and temperature first and second moments with changing in the Rayleigh number. > Strong decoupling between the turbulent kinetic energy and the dissipation rate. > Particle recirculation sustained by the vertical hot boundary layer. > Deposition mostly induced by gravity, thermophoretic and lift forces are negligible. - Abstract: In this work we investigate numerically particle deposition in the buoyancy driven flow of the differentially heated cavity (DHC). We consider two values of the Rayleigh number (Ra = 10{sup 9}, 10{sup 10}) and three values of the particle diameter (d{sub p} = 15, 25, 35 [{mu}m]). We consider the cavity filled with air and particles with the same density of water {rho}{sub w} = 1000 [kg/m{sup 3}] (aerosol). We use direct numerical simulations (DNS) for the continuous phase, and we solve transient Navier-Stokes and energy transport equations written in an Eulerian framework, under the Boussinesq approximation, for the viscous incompressible Newtonian fluid with constant Prandtl number (Pr = 0.71). First- and second-order statistics are presented for the continuous phase as well as important quantities like turbulent kinetic energy (TKE) and temperature variance with the associated production and dissipation fields. The TKE production shows different behaviour at the two Rayleigh numbers. The Lagrangian approach has been chosen for the dispersed phase description. The forces taken into account are drag, gravity, buoyancy, lift and thermophoresis. A first incursion in the sedimentation mechanisms is presented. Current results indicate that the largest contribution to particle deposition is caused by gravitational settling, but a strong recirculating zone, which liftoffs and segregates particles, contributes to decrease settling. Deposition takes place mostly at the bottom wall. The influence of lift

  18. Hypokalaemia and subsequent hyperkalaemia in hospitalized patients

    NARCIS (Netherlands)

    M.J. Crop (Meindert); E.J. Hoorn (Ewout); J. Lindemans (Jan); R. Zietse (Bob)

    2007-01-01

    textabstractBackground. The objective was to study the epidemiology of hypokalaemia [serum potassium concentration (SK) <3.5 mmol/l] in a general hospital population, specifically focusing on how often and why patients develop subsequent hyperkalaemia (SK<5.0 mmol/l). Methods. In a 3-month

  19. Subsequent childbirth after a previous traumatic birth.

    Science.gov (United States)

    Beck, Cheryl Tatano; Watson, Sue

    2010-01-01

    Nine percent of new mothers in the United States who participated in the Listening to Mothers II Postpartum Survey screened positive for meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for posttraumatic stress disorder after childbirth. Women who have had a traumatic birth experience report fewer subsequent children and a longer length of time before their second baby. Childbirth-related posttraumatic stress disorder impacts couples' physical relationship, communication, conflict, emotions, and bonding with their children. The purpose of this study was to describe the meaning of women's experiences of a subsequent childbirth after a previous traumatic birth. Phenomenology was the research design used. An international sample of 35 women participated in this Internet study. Women were asked, "Please describe in as much detail as you can remember your subsequent pregnancy, labor, and delivery following your previous traumatic birth." Colaizzi's phenomenological data analysis approach was used to analyze the stories of the 35 women. Data analysis yielded four themes: (a) riding the turbulent wave of panic during pregnancy; (b) strategizing: attempts to reclaim their body and complete the journey to motherhood; (c) bringing reverence to the birthing process and empowering women; and (d) still elusive: the longed-for healing birth experience. Subsequent childbirth after a previous birth trauma has the potential to either heal or retraumatize women. During pregnancy, women need permission and encouragement to grieve their prior traumatic births to help remove the burden of their invisible pain.

  20. Subsequent Reproductive Performance in Survivors of Complicated ...

    African Journals Online (AJOL)

    Objective To study the subsequent reproductive performance of women who had undergone complicated abortions. Materials and Methods Attempts were made to trace 299 survivors of complicated abortions from an earlier study. Their contact telephone numbers and addresses had been recorded at the time of initial ...

  1. 75 FR 346 - Proposed Subsequent Arrangement

    Science.gov (United States)

    2010-01-05

    ... Uses of Nuclear Energy. This subsequent arrangement concerns the retransfer of 28,409 kg of U.S.-origin... Fuels in Kanakawa-ken, Japan. The material, which is currently located at Cameco, Port Hope, Ontario, will be transferred to Global Nuclear Fuel, Kanakawa-ken, Japan to be fabricated into fuel pellets and...

  2. 78 FR 72072 - Proposed Subsequent Arrangement

    Science.gov (United States)

    2013-12-02

    ... g of U.S.-origin atomized low-enriched uranium-7wt. % molybdenum powder, containing 365.638 g in the..., which is located at and was prepared by KAERI, will be used for the irradiation test of full-size fuel... subsequent arrangement concerning the retransfer of nuclear material of United States origin will not be...

  3. 78 FR 40131 - Proposed Subsequent Arrangement

    Science.gov (United States)

    2013-07-03

    ... INFORMATION: This subsequent arrangement concerns the retransfer of 302,188 kg of U.S.-origin natural uranium..., Saskatchewan, Canada, to Springfields Fuels Ltd. in Lancashire, United Kingdom. The material, which is... arrangement concerning the retransfer of nuclear material of United States origin will not be inimical to the...

  4. The influence of different salinity conditions on egg buoyancy and development and yolk sac larval survival and morphometric traits of Baltic Sea sprat (Sprattus sprattus balticus Schneider

    Directory of Open Access Journals (Sweden)

    Christoph Petereit

    2009-10-01

    Full Text Available The small pelagic sprat (Sprattus sprattus is a key ecologic player in the Baltic Sea. However, there is long-term variability in recruitment which is thought to be influenced by fluctuations in abiotic and biotic conditions experienced during the early life stages. This study concentrates on the influence of different ambient salinities on sprat egg development, egg buoyancy and survival as well as early yolk sac larval morphometric traits. Egg buoyancy significantly decreased with increasing salinity experienced during fertilization and/or incubation experiments. Field egg buoyancy measurements in 2007 and 2008 exhibited annual and seasonal differences in specific gravity, potentially associated with changes in adult sprat vertical distribution. Neither egg development time nor the duration of the yolk sac phase differed among salinity treatments. At eye pigmentation, larval standard length exhibited high variance among individuals but did not differ among treatments. The largest ecological impact of salinity experienced during spawning was the modification the buoyancy of eggs and yolk sac larvae, which determines their vertical habitat in the Baltic Sea. There are strong thermo- and oxyclines in the Baltic Sea, and thus salinity can indirectly impact the survival of these early life stages by modifying the ambient temperatures and oxygen conditions experienced.

  5. Buoyancy Effect of Ionic Vacancy on the Change of the Partial Molar Volume in Ferricyanide-Ferrocyanide Redox Reaction under a Vertical Gravity Field

    Directory of Open Access Journals (Sweden)

    Yoshinobu Oshikiri

    2013-01-01

    Full Text Available With a gravity electrode (GE in a vertical gravity field, the buoyancy effect of ionic vacancy on the change of the partial molar volume in the redox reaction between ferricyanide (FERRI and ferrocyanide (FERRO ions was examined. The buoyancy force of ionic vacancy takes a positive or negative value, depending on whether the rate-determining step is the production or extinction of the vacancy. Though the upward convection over an upward electrode in the FERRO ion oxidation suggests the contribution of the positive buoyancy force arising from the vacancy production, the partial molar volume of the vacancy was not measured. On the other hand, for the downward convection under a downward electrode in the FERRI ion reduction, it was not completely but partly measured by the contribution of the negative buoyancy force from the vacancy extinction. Since the lifetime of the vacancy is decreased by the collision between ionic vacancies during the convection, the former result was ascribed to the shortened lifetime due to the increasing collision efficiency in the enhanced upward convection over an upward electrode, whereas the latter was thought to arise from the elongated lifetime due to the decreasing collision efficiency by the stagnation under the downward electrode.

  6. Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

    Science.gov (United States)

    Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

    2018-02-01

    The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

  7. The effect of buoyancy on flow and heat transfer for a gas passing down a vertical pipe at low turbulent reynolds numbers

    International Nuclear Information System (INIS)

    Easby, J.P.

    1978-01-01

    For the analysis of low-flow situations in the core of the High-Temperature Gas-Cooled reactor it is necessary to have a knowledge of the variation of pressure drop and heat transfer with flow and buoyancy influence. Nitrogen at 4 bar has been used to simulate the high pressure helium in the reactor and an experiment performed for downward flow in a heated vertical pipe. The measurements show that for the range of flow and buoyancy influence parameters investigated, (2000 6 ), friction factors are reduced by up to 20% compared with a correlation for isothermal flows and heat transfer is increased by up to 40% compared with a correlation for constant fluid properties. Agreement with the limit amount of previous data is quite satisfactory. The changes in heat transfer and friction factor with buoyancy influence can be attributed to distortion of the normally linear, radial shear stress profile. Simple equations have been determined to correlate the present results but extrapolation to conditions of high flow and buoyancy influence, where the interaction of forced and free convection may be different, is not advised. (author)

  8. Factors of academic procrastination

    OpenAIRE

    Kranjec, Eva; Košir, Katja; Komidar, Luka

    2017-01-01

    This study investigated dimensions of perfectionism, anxiety, and depression as factors of academic procrastination. Our main research interest was to examine the role of specific dimensions of perfectionism as moderators in the relationship between anxiety and depression and academic procrastination. Four scales were administered on the sample of 403 students: perfectionism scale FMPS, academic procrastination scale APS-SI, depression scale CESD and anxiety scale STAI-X2. The results showed ...

  9. Association of Periodontitis and Subsequent Depression

    Science.gov (United States)

    Hsu, Chih-Chao; Hsu, Yi-Chao; Chen, Hsuan-Ju; Lin, Che-Chen; Chang, Kuang-Hsi; Lee, Chang-Yin; Chong, Lee-Won; Kao, Chia-Hung

    2015-01-01

    Abstract Periodontitis is a systemic and chronic inflammatory disease associated with multiple physical conditions. Distress and depression are other problems affecting the progression of periodontitis. However, the causal relationship between depression and periodontitis has not been adequately investigated. This aim of this study was to determine the association between periodontitis and the subsequent development of depression. We identified 12,708 patients with newly diagnosed periodontitis from 2000 to 2005 and 50,832 frequency-matched individuals without periodontitis. Both groups were followed until diagnosed with depression, withdrawal from the National Health Insurance program, or the end of 2011. The association between periodontitis and depressio was analyzed using Cox proportional hazard regression models. The incidence density rate of depression was higher in the periodontitis group than in the nonperiodontitis group, with an adjusted hazard ratio of 1.73 (95% confidence interval 1.58–1.89) when adjusting for sex, age, and comorbidity. Cox models revealed that periodontitis was an independent risk factor for depression in patients, except for comorbidities of diabetes mellitus (DM), alcohol abuse, and cancer. Periodontitis may increase the risk of subsequent depression and was suggested an independent risk factor regardless of sex, age, and most comorbidities. However, DM, alcohol abuse, and cancer may prevent the development of subsequent depression because of DM treatment, the paradoxical effect of alcohol, and emotional distress to cancer, respectively. Prospective studies on the relationship between periodontitis and depression are warranted. PMID:26705230

  10. Reactions to abortion and subsequent mental health.

    Science.gov (United States)

    Fergusson, David M; Horwood, L John; Boden, Joseph M

    2009-11-01

    There has been continued interest in the extent to which women have positive and negative reactions to abortion. To document emotional reactions to abortion, and to examine the links between reactions to abortion and subsequent mental health outcomes. Data were gathered on the pregnancy and mental health history of a birth cohort of over 500 women studied to the age of 30. Abortion was associated with high rates of both positive and negative emotional reactions; however, nearly 90% of respondents believed that the abortion was the right decision. Analyses showed that the number of negative responses to the abortion was associated with increased levels of subsequent mental health disorders (Pabortion and reporting negative reactions had rates of mental health disorders that were approximately 1.4-1.8 times higher than those not having an abortion. Abortion was associated with both positive and negative emotional reactions. The extent of negative emotional reactions appeared to modify the links between abortion and subsequent mental health problems.

  11. Induced abortion and subsequent pregnancy duration

    DEFF Research Database (Denmark)

    Zhou, Wei Jin; Sørensen, Henrik Toft; Olsen, Jørn

    1999-01-01

    OBJECTIVE: To examine whether induced abortion influences subsequent pregnancy duration. METHODS: Women who had their first pregnancies during 1980, 1981, and 1982 were identified in three Danish national registries. A total of 15,727 women whose pregnancies were terminated by first-trimester ind......OBJECTIVE: To examine whether induced abortion influences subsequent pregnancy duration. METHODS: Women who had their first pregnancies during 1980, 1981, and 1982 were identified in three Danish national registries. A total of 15,727 women whose pregnancies were terminated by first......-trimester induced abortions were compared with 46,026 whose pregnancies were not terminated by induced abortions. All subsequent pregnancies until 1994 were identified by register linkage. RESULTS: Preterm and post-term singleton live births were more frequent in women with one, two, or more previous induced...... abortions. After adjusting for potential confounders and stratifying by gravidity, the odds ratios of preterm singleton live births in women with one, two, or more previous induced abortions were 1.89 (95% confidence interval [CI] 1.70, 2.11), 2.66 (95% CI 2.09, 3.37), and 2.03 (95% CI 1.29, 3...

  12. From Academic to Post-Academic Science

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Ghaneirad

    2014-03-01

    Full Text Available This paper studies the cultural change in science from academic science to post-academic science by the use of documentary studying and analytical reasoning. The aim of this study is determining the direction of cultural change in science and comparing it with cultural change in society.The knowledge production which surrounds academy has little relationship with the values of society and epistemological norms regulate scientists' behavior from within the scientific system. But in post-academic science the relationship between science and society operates in the same line with market and government and science produce within the social context and scientists' behavior controlled by the norms out of the scientific system. So the culture of science has changed because science applied to meet the requirements of market and industry. The result is that contrary to cultural change in society that goes from materialism to post-materialism, cultural change in science moves from post-materialism to materialism.

  13. Students' Academic Performance: Academic Effort Is an Intervening ...

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH ... Students' Academic Performance: Academic Effort Is an Intervening Variable ... This study was designed to seek explanations for differences in academic performance among junior ...

  14. Effect of antenatal exposure to maternal smoking on behavioural problems and academic achievement in childhood : prospective evidence from a Dutch birth cohort

    NARCIS (Netherlands)

    Batstra, L; Hadders-Algra, M; Neeleman, J

    2003-01-01

    Aim: To examine effects of maternal smoking during pregnancy on academic achievement and emotional and behavioural problems during childhood. Methods: Least squares regression was used to examine associations between maternal smoking prior to delivery and subsequent academic performance and

  15. Thinking Academic Freedom

    Science.gov (United States)

    Lange, Lis

    2016-01-01

    This lecture argues that the politicisation and instrumentalisation of the university caused by neoliberal frames has as a result the depoliticisation of knowledge and of the academic as individual. This depoliticisation has turned academic freedom into a right to disengage not only from the political fight around these issues but also from the…

  16. Academic Work and Performativity

    Science.gov (United States)

    Kenny, John

    2017-01-01

    Neoliberal reforms in higher education have resulted in corporate managerial practices in universities and a drive for efficiency and productivity in teaching and research. As a result, there has been an intensification of academic work, increased stress for academics and an emphasis on accountability and performativity in universities. This paper…

  17. Patterns of Academic Procrastination.

    Science.gov (United States)

    Day, Victor; Mensink, David; O'Sullivan, Michael

    2000-01-01

    Uses the Academic Procrastination Questionnaire to measure procrastination and six possible patterns underlying it among undergraduate students. Finds that the most common patterns for clients involved Evaluation Anxiety or being Discouraged/Depressed, or Dependent. Supports individualized assessment and solutions for academic procrastination. (SC)

  18. Marketing Academic Libraries

    Science.gov (United States)

    Mallon, Melissa, Ed.

    2013-01-01

    Ask any academic librarian if marketing their library and its services is an important task, and the answer will most likely be a resounding "yes!" Particularly in economically troubled times, librarians are increasingly called upon to promote their services and defend their library's worth. Since few academic libraries have in-house marketing…

  19. Relocalising academic literacy

    DEFF Research Database (Denmark)

    Clemensen, Nana; Holm, Lars

    2017-01-01

    This article contributes to the continuing discussion about academic literacy in international higher education. Approaching international study programmes as temporary educational contact zones, marked by a broad diversity in students’ educational and discursive experiences, we examine the negot......This article contributes to the continuing discussion about academic literacy in international higher education. Approaching international study programmes as temporary educational contact zones, marked by a broad diversity in students’ educational and discursive experiences, we examine...... the negotiation and relocalisation of academic literacy among students of the international master’s programme, Anthropology of Education and Globalisation (AEG), University of Aarhus, Denmark. The article draws on an understanding of academic literacy as a local practice situated in the social and institutional...... contexts in which it appears. Based on qualitative interviews with eleven AEG-students, we analyse students’ individual experiences of, and perspectives on, the academic literacy practices of this study programme. Our findings reveal contradictory understandings of internationalism and indicate a learning...

  20. Does Academic Work Make Australian Academics Happy?

    Science.gov (United States)

    Duncan, Roderick; Tilbrook, Kerry; Krivokapic-Skoko, Branka

    2015-01-01

    Happiness research is a rapidly-growing area in social psychology and has emphasised the link between happiness and workplace productivity and creativity for knowledge workers. Recent articles in this journal have raised concerns about the level of happiness and engagement of Australian academics with their work, however there is little research…

  1. Tritium sorption by cement and subsequent release

    International Nuclear Information System (INIS)

    Ono, F.; Yamawaki, M.

    1995-01-01

    In a fusion reactor or tritium-handling facilities, contamination of concrete by tritium and subsequent release from it to the reator or experimental room is a matter of problem for safe control of tritium and management of operational environment. In order to evaluate this tritium behavior, interaction of tritiated water with concrete or cement should be clarified. In the present study, HTO sorption and subsequent release from cement were experimentally studied.(1)Sorption experiments were conducted using columns packed with cement particles of different sizes. From the analysis of the breakthrough curve, tritium diffusivity in macropores and microparticles were evaluated.(2)From the short-term tritium release experiments, effective desorption rate constants were evaluated and the effects of temperature and moisture were studied.(3)In the long-term tritium release experiments to 6000h, the tritium release mechanism was found to be composed of three kinds of water: initially from capillary water, and in the second stage from gel water and from the water in the cement crystal.(4)Tritium release behavior by heat treatment to 800 C was studied. A high temperature above 600 C was required for the tritium trapped in the crystal water to be released. (orig.)

  2. Workplace bullying and subsequent health problems.

    Science.gov (United States)

    Nielsen, Morten Birkeland; Magerøy, Nils; Gjerstad, Johannes; Einarsen, Ståle

    2014-07-01

    Cross-sectional studies demonstrate that exposure to bullying in the workplace is positively correlated with self-reported health problems. However, these studies do not provide a basis to draw conclusions on the extent to which bullying leads to increased health problems or whether health problems increase the risk of being bullied. To provide better indications of a causal relationship, knowledge from prospective studies on the association between bullying in the workplace and health outcomes is therefore summarised. We conducted a systematic literature review of original articles from central literature databases on longitudinal associations between bullying in the workplace and health. Average associations between bullying and health outcomes are calculated using meta-analysis. A consistent finding across the studies is that exposure to bullying is significantly positively related to mental health problems (OR =1.68; 95% KI 1.35-2.09) and somatic symptoms (OR = 1.77; 95% KI 1.41-2.22) over time. Mental health problems are also associated with subsequent exposure to bullying (OR = 1.74; 95% KI 1.44-2.12). Bullying is positively related to mental health problems and somatic symptoms. The association between mental health problems and subsequent bullying indicates a self-reinforcing process between mental health and bullying. The methodological quality of the studies that were conducted is relatively sound. However, based on the existing knowledge base there are no grounds for conclusions regarding an unambiguous causal relationship between bullying and health.

  3. Supporting research in area studies a guide for academic libraries

    CERN Document Server

    Pitman, Lesley

    2015-01-01

    Supporting Research in Area Studies: A Guide for Academic Libraries focuses on the study of other countries or regions of the world, crossing traditional disciplinary boundaries in the humanities and social sciences. The book provides a comprehensive guide for academic libraries supporting communities of researchers, exploring the specialist requirements of these researchers in information resources, resource discovery tools, information skills, and the challenges of working with materials in multiple languages. The book makes the case that adapting systems and procedures to meet these needs will help academic libraries be better placed to support their institutions' international agenda. Early chapters cover the academic landscape, its history, area studies, librarianship, and acquisitions. Subsequent chapters discuss collections management, digital products, and the digital humanities, and their role in academic projects, with final sections exploring information skills and the various disciplinary skills t...

  4. The academic prince.

    Science.gov (United States)

    McGregor, Maurice

    2002-12-01

    The author presents advice to deans and chairs of academia by imagining what Machiavelli might recommend were he to write a modern version of The Prince for academics. "Machiavelli" cautions that since modern academic "princes" have little power (except, perhaps, over teaching and laboratory space), the success of their rule depends upon respect. Regarding the choice of an academic prince, find someone who can be a good role model, set standards, and reward academic excellence, and who will, above all, be respected. Avoid choosing a prince who is a nice, nonthreatening candidate with "good human relations" and "good executive skills." Choose candidates who are already successful and fulfilled and who will see the new post not as a promotion or a balm for their insecurity, but as an intrusion into their academic lives. Fill empty positions as quickly as possible-better a weak prince than no prince at all. Seek short terms for princes, both because respected academics will want to return to their normal lives as soon as possible, and because with short mandates, greater chances can be taken with young, unproved, but promising candidates. At the same time, the appointment of aging administrators who have lost their academic skills is to be avoided. Above all, respect the throne-i.e., the position of chair or dean-even if the person holding the position may not deserve the respect, since when the prince retires with honor, the position becomes more attractive to future good candidates.

  5. Gas mixing under the influence of thermal-dynamic parameters such as buoyancy, jet momentum and fan-induced convection

    International Nuclear Information System (INIS)

    Chan, C.K.; Jones, S.C.A.

    1994-01-01

    Various scaling parameters for simulating mixing under the influence of buoyancy, jet momentum, and fan-induced convection were examined. Their significance was assessed by comparing the mixing of helium (a simulant for hydrogen) with air in a large-scale enclosure (1.8 m x 1.8 m x 1.8 m) to the mixing of salt-water with fresh-water in a small-scale enclosure (1/6 the size). The advantage of using the salt-water/freshwater technique is that it allows the characteristic flow regime (either turbulent or laminar flow) in the full-scale containment to be maintained in the reduced scale containment. A smoke technique for flow visualization was used to examine the mixing of the helium with air. For the small-scale salt-water/fresh-water experiment, fluorescent dye was used to provide a means to visualize the mixing process. The mixing behaviour in both sets of experiments were analyzed based on video records and concentration measurements in ten locations. Measurements showed that depending on the recirculation and jet flow rates, the injected salt-water (in small-scale experiments) and helium (in large-scale experiments) can disperse sufficiently quickly to produce an essentially 'well mixed' condition rendering the concentration measurements insensitive to the variation in the Froude or the Grashof Numbers. (author)

  6. Influence of the variable thermophysical properties on the turbulent buoyancy-driven airflow inside open square cavities

    Science.gov (United States)

    Zamora, Blas; Kaiser, Antonio S.

    2012-01-01

    The effects of the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated, as well as the influence of the stated boundary conditions at open edges and the employed differencing scheme. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low-Reynolds k - ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide and not yet covered range of the Rayleigh number varying from 103 to 1016. The results obtained taking into account variable properties effects are compared with those calculated assuming constant properties and the Boussinesq approximation. For uniform heat flux heating, a correlation for the critical heating parameter above which the burnout phenomenon can be obtained is presented, not reported in previous works. The effects of variable properties on the flow patterns are analyzed.

  7. Coexisting contraction-extension consistent with buoyancy of the crust and upper mantle in North-Central Italy

    CERN Document Server

    Aoudia, A; Ismail-Zadeh, A T; Panza, G F; Pontevivo, A

    2002-01-01

    The juxtaposed contraction and extension observed in the crust of the Italian Apennines and elsewhere has, for a long time, attracted the attention of geoscientists and is a long-standing enigmatic feature. Several models, invoking mainly external forces, have been put forward to explain the close association of these two end-member deformation mechanisms clearly observed by geophysical and geological investigations. These models appeal to interactions along plate margins or at the base of the lithosphere such as back-arc extension or shear tractions from mantle flow or to subduction processes such as slab roll back, retreat or pull and detachment. We present here a revisited crust and upper mantle model that supports delamination processes beneath North-Central Italy and provides a new background for the genesis and age of the recent magmatism in Tuscany. Although external forces must have been important in the building up of the Apennines, we show that internal buoyancy forces solely can explain the coexist...

  8. The impact of pressure-dependent interfacial tension and buoyancy forces upon pressure depletion in virgin hydrocarbon reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, S.R.; Mackay, E.J. [Heriot-Watt University, Edinburgh (United Kingdom). Dept. of Petroleum Engineering

    1998-07-01

    This paper describes a combined experimental and theoretical study of the microscopic pore-scale physics characterizing gas and liquid production from hydrocarbon reservoirs during pressure depletion. The primary focus of the study was to examine the complex interactions between interfacial tension and buoyancy forces during gas evolution within a porous medium containing oil, water and gas. A specialized 2-dimensional glass micromodel, capable of operating at pressure in excess of 35 MPa was used to visualize the physical mechanisms governing such microscopic processes. In addition, a 3-dimensional, 3-phase numerical pore-scale simulator was developed that can be used to examine gas evolution over a range of different lengthscales and for a wide range of fluid and rock properties. The model incorporates all of the important physics observed in associated laboratory micromodel experiments, including: embryonic nucleation, supersaturation effects, multiphase diffusion, bubble growth-migration-fragmentation, and three-phase spreading coefficients. The precise pore-scale mechanisms governing gas evolution were found to be far more subtle than earlier models would suggest because of the large variation of gas/oil interfacial tension with pressure. This has a profound effect upon the migration of gas structures during depletion and, in models pertaining to reservoir rock, the process of gas migration is consequently much slower than previously thought. This is the first time that such a phenomena has been modelled at the pore-scale and the implications for production forecasting are thought to be significant. (author)

  9. Dynamic pore network simulator for modelling buoyancy-driven migration during depressurisation of heavy-oil systems

    Energy Technology Data Exchange (ETDEWEB)

    Ezeuko, C.C.; McDougall, S.R. [Heriot-Watt Univ., Edinburgh (United Kingdom); Bondino, I. [Total E and P UK Ltd., London (United Kingdom); Hamon, G. [Total S.A., Paris (France)

    2008-10-15

    In an attempt to investigate the impact of gravitational forces on gas evolution during solution gas drive, a number of vertically-oriented heavy oil depletion experiments have been conducted. Some of the results of these studies suggest the occurrence of gas migration during these tests. However, a major limitation of these experiments is the difficulty in visualizing the process in reservoir rock samples. Experimental observations using transparent glass models have been useful in this context and provide a sound physical basis for modelling gravitational gas migration in gas-oil systems. This paper presented a new pore network simulator that was capable of modelling the time-dependent migration of growing gas structures. Multiple pore filling events were dynamically modelled with interface tracking allowing the full range of migratory behaviours to be reproduced, including braided migration and discontinuous dispersed flow. Simulation results were compared with experiments and were found to be in excellent agreement. The paper presented the model and discussed the implication of evolution regime on recovery from heavy oil systems undergoing depressurization. The simulation results demonstrated the complex interaction of a number of network and fluid parameters. It was concluded that the concomitant effect on the competition between capillarity and buoyancy produced different gas evolution patterns during pressure depletion. 28 refs., 2 tabs., 19 figs.

  10. ROLE OF MAGNETIC FIELD STRENGTH AND NUMERICAL RESOLUTION IN SIMULATIONS OF THE HEAT-FLUX-DRIVEN BUOYANCY INSTABILITY

    International Nuclear Information System (INIS)

    Avara, Mark J.; Reynolds, Christopher S.; Bogdanović, Tamara

    2013-01-01

    The role played by magnetic fields in the intracluster medium (ICM) of galaxy clusters is complex. The weakly collisional nature of the ICM leads to thermal conduction that is channeled along field lines. This anisotropic heat conduction profoundly changes the instabilities of the ICM atmosphere, with convective stabilities being driven by temperature gradients of either sign. Here, we employ the Athena magnetohydrodynamic code to investigate the local non-linear behavior of the heat-flux-driven buoyancy instability (HBI) relevant in the cores of cooling-core clusters where the temperature increases with radius. We study a grid of two-dimensional simulations that span a large range of initial magnetic field strengths and numerical resolutions. For very weak initial fields, we recover the previously known result that the HBI wraps the field in the horizontal direction, thereby shutting off the heat flux. However, we find that simulations that begin with intermediate initial field strengths have a qualitatively different behavior, forming HBI-stable filaments that resist field-line wrapping and enable sustained vertical conductive heat flux at a level of 10%-25% of the Spitzer value. While astrophysical conclusions regarding the role of conduction in cooling cores require detailed global models, our local study proves that systems dominated by the HBI do not necessarily quench the conductive heat flux

  11. Activity recognition from minimal distinguishing subsequence mining

    Science.gov (United States)

    Iqbal, Mohammad; Pao, Hsing-Kuo

    2017-08-01

    Human activity recognition is one of the most important research topics in the era of Internet of Things. To separate different activities given sensory data, we utilize a Minimal Distinguishing Subsequence (MDS) mining approach to efficiently find distinguishing patterns among different activities. We first transform the sensory data into a series of sensor triggering events and operate the MDS mining procedure afterwards. The gap constraints are also considered in the MDS mining. Given the multi-class nature of most activity recognition tasks, we modify the MDS mining approach from a binary case to a multi-class one to fit the need for multiple activity recognition. We also study how to select the best parameter set including the minimal and the maximal support thresholds in finding the MDSs for effective activity recognition. Overall, the prediction accuracy is 86.59% on the van Kasteren dataset which consists of four different activities for recognition.

  12. Academic Training: 2004 - 2005 ACADEMIC TRAINING PROGRAMME

    CERN Multimedia

    Françoise Benz

    2004-01-01

    1st Term - 01 October to 17 December 2004 REGULAR LECTURE PROGRAMME New Trends in Fusion Research by A. Fasoli, EPFL, Lausanne, CH 11, 12, 13 October Physics at e+e- linear collider by K. Desch, DESY, Hamburg, D 15, 16, 17, 18, 19 November LECTURE SERIES FOR POSTGRADUATE STUDENTS Standard Model by R. Barbieri, CERN-PH-TH 6, 7, 8, 9 10 December The lectures are open to all those interested, without application. The abstract of the lectures, as well as any change to the above information (title, dates, time, place etc) will be published in the CERN Bulletin, the WWW, and by notices before each term and for each series of lectures. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

  13. Experimental Study of a natural ventilation strategy in a Full-Scale Enclosure Under Meteorological Conditions: A Buoyancy-Driven Approach

    OpenAIRE

    Austin, Miguel Chen; Bruneau, Denis; Sempey, Alain; Mora, Laurent; Sommier, Alain

    2018-01-01

    The performance of a natural ventilation strategy, in a full-scale enclosure under meteorological conditions is studied through an experimental study, a buoyancy-driven approach, by means of the estimation of the air exchange rate per hour and ventilation power. A theoretical and an empirical model are proposed based on the airflow theory in buildings and blower-door tests. A preliminary validation, by comparing our results with standards in air leakage rate determination, is made. The experi...

  14. Academic Capitalism and Academic Culture: A Case Study

    Science.gov (United States)

    Mendoza, Pilar; Berger, Joseph B.

    2008-01-01

    This case study investigated the impact of academic capitalism on academic culture by examining the perspectives of faculty members in an American academic department with significant industrial funding. The results of this study indicate that faculty members believe that the broad integrity of the academic culture remains unaffected in this…

  15. Academic Self-Perception and Its Relationship to Academic Performance

    Science.gov (United States)

    Stringer, Ronald W.; Heath, Nancy

    2008-01-01

    One hundred and fifty-five students (average age, 10 years 7 months) were initially tested on reading, arithmetic, and academic self-perception. One year later they were tested again. Initial academic scores accounted for a large proportion of the variance in later academic scores. The children's self-perceptions of academic competence accounted…

  16. Academic librarianship today

    CERN Document Server

    2017-01-01

    Intended for use by both librarians and students in LIS programs, Academic Librarianship Today is the most current, comprehensive overview of the field available today. Key features include: Each chapter was commissioned specifically for this new book, and the authors are highly regarded academic librarians or library school faculty— or both Cutting-edge topics such as open access, copyright, digital curation and preservation, emerging technologies, new roles for academic librarians, cooperative collection development and resource sharing, and patron-driven acquisitions are explored in depth Each chapter ends with thought-provoking questions for discussion and carefully constructed assignments that faculty can assign or adapt for their courses The book begins with Gilman’s introduction, an overview that briefly synthesizes the contents of the contributors’ chapters by highlighting major themes. The main part of the book is organized into three parts: The Academic Library Landscape Today, ...

  17. Declaration of Academic Freedom

    Directory of Open Access Journals (Sweden)

    Gökhan ÇETİNSAYA

    2014-04-01

    Full Text Available 1. Universities are the institutions where all the opinions, various truth claims as well as social and political problems are discussed in a liberal and civilized way and the complicated problems are expressed clearly without any oppression and prevention. 2. Academic freedom includes first and foremost the right of freedom of research and thus freedom of using the essential knowledge methods, the right of possessing the necessary tools and conditions required for the research and the rights of scientific production, informing, learning and dissemination. 3. Academics possess the rights to benefit from the academic freedom without any limitation, to research and investigate according to their own preferences and interests, and to teach these without being exposed to any oppression and prevention. 4. This freedom of teaching that the academics have should not be used in a manner restricting students' freedom of learning; academics should avoid from being dogmatic in the research and education processes and respect students' rights of thinking differently and expressing themselves. 5. Academics accordingly should lead the students to evaluate and understand the new thoughts as a whole and to be tolerant to the thoughts they do not agree and to think in various ways. Also, academics should encourage the students to create their own opinions based on evidences and enable them to express these opinions freely and respect their freedom of expression. 6. Campuses should be safe environments where the students can express their own opinions freely. Suppressing the intellectual diversity and the plurality of viewpoints will decrease the productivity of teaching and learning process, restrict students' freedom of learning, and constrain the chance of formation of critical and in-depth thinking. 7. Critical thinking develops only in the campuses where various thoughts are expressed in a liberal way. Students should feel that they would not be prevented

  18. Googilum academic gaveshana librarikalum

    OpenAIRE

    Vijayakumar, J. K.

    2006-01-01

    Describes about two projects of Google such as "Google Scholar" and "Google Print".It also describes how the traditional library based academic research information search can be affected by these two projects.

  19. Academic goals in surgery.

    Science.gov (United States)

    Bleier, Joshua I S; Kann, Brian

    2013-12-01

    The development of an academic surgical career can be an overwhelming prospect, and one that is not intuitive. Establishing a structured plan and support structure is critical to success. Starting a successful academic surgical career begins with defining one's academic goals within several broad categories: personal goals, academic goals, research goals, educational goals, and financial goals. Learning the art of self-promotion is the means by which many of these goals are achieved. It is important to realize that achieving these goals requires a delicate personal balance between work and home life, and the key ways in which to achieve success require establishment of well thought-out goals, a reliable support structure, realistic and clear expectations, and frequent re-evaluation.

  20. Administering an Academic Department.

    Science.gov (United States)

    Hicks, Donald W.; Sperry, John B.

    1986-01-01

    Clarifies the possible forms of leadership taken by the administrator of an academic department. Discusses such elements as authoritarian leadership, faculty consensus, power and responsibility, input factors, types of decision making, faculty recruiting, and authoritarian versus democratic approach. (CT)

  1. The academic quilting bee.

    Science.gov (United States)

    Mayer, Anita P; Files, Julia A; Ko, Marcia G; Blair, Janis E

    2009-03-01

    In medicine, the challenges faced by female faculty members who are attempting to achieve academic advancement have been well described. Various strategies have been proposed to increase academic productivity to aid the promotion of women in medicine. We propose an innovative collaboration strategy that encourages completion of an academic writing project. This strategy acknowledges the challenges inherent in achieving work-life balance and utilizes a collaborative work style with a group of peer physicians. The model is designed to encourage the completion and collation of independently prepared sections of an academic paper within a setting that emphasizes social networking and collaboration. This approach has many similarities to the construction of a quilt during a "quilting bee."

  2. Thermo capillary and buoyancy convection in a fluid locally heated on its free surface; Convection thermocapillaire et thermogravitaire dans un fluide chauffe localement sur sa surface libre

    Energy Technology Data Exchange (ETDEWEB)

    Favre, E.

    1997-09-26

    coupled buoyancy and thermo-capillary convection lead to a convective motion of the interface liquid/gas which drastically changes the heat and mass transfer across the liquid layer. Two experiments were considered, depending on the fluid: oil or mercury. The liquid is set in a cooled cylindrical vessel, and heated by a heat flux across the center of the free surface. The basic flow, in the case of oil, is a torus. When the heat parameter increases, a stationary flow appears as petals or rays when the aspect ratio. The lateral confinement selects the azimuthal wavelength. In the case of petals-like flow, a sub-critical Hopf bifurcation is underlined. The turbulence is found to be `weak`, even for the largest values of the Marangoni number (Ma = 1.3 10{sup 5}). In the case of mercury, the thermo-capillary effect is reduced to zero to impurities at the surface which have special trajectories we describe and compare to a simpler experiment. Only the buoyancy forces induce a unstationary, weakly turbulent flow as soon as the heating power exceeds 4W (Ra = 4.5 10{sup 3}, calculated with h = 1 mm). The past part concerns the analysis of the effect on the flow of the boundary conditions, the geometry, the Prandtl number and the buoyancy force with the help of the literature. Results concerning heat transfer, in particular the exponent of the law Nusselt number vs. heating power, were compared with available data. (author) 115 refs.

  3. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    KAUST Repository

    Kong, X.; Delshad, M.; Wheeler, M. F.

    2012-01-01

    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  4. An Integrated Capillary, Buoyancy, and Viscous-Driven Model for Brine/CO2Relative Permeability in a Compositional and Parallel Reservoir Simulator

    KAUST Repository

    Kong, X.

    2012-11-03

    The effectiveness of CO2 storage in the saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental study reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on pressure (IFT) is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in subsurface is crucial to design future storage projects that warrant long-term and safe containment. Simulation studies ignoring the buoyancy and also variation in interfacial tension and the effect on the petrophysical properties such as trapped CO2 saturations, relative permeability, and capillary pressure have a poor chance of making accurate predictions of CO2 injectivity and plume migration. We have developed and implemented a general relative permeability model that combines effects of pressure gradient, buoyancy, and IFT in an equation of state (EOS) compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed.

  5. Academic Engagement and Commercialisation

    DEFF Research Database (Denmark)

    Perkmann, Markus; Tartari, Valentina; McKelvey, Maureen

    2013-01-01

    A considerable body of work highlights the relevance of collaborative research, contract research, consulting and informal relationships for university–industry knowledge transfer. We present a systematic review of research on academic scientists’ involvement in these activities to which we refer......, and pursued by academics to access resources supporting their research agendas. We conclude by identifying future research needs, opportunities for methodological improvement and policy interventions....

  6. Whistleblowing in academic medicine.

    Science.gov (United States)

    Rhodes, R; Strain, J J

    2004-02-01

    Although medical centres have established boards, special committees, and offices for the review and redress of breaches in ethical behaviour, these mechanisms repeatedly prove themselves ineffective in addressing research misconduct within the institutions of academic medicine. As the authors see it, institutional design: (1) systematically ignores serious ethical problems, (2) makes whistleblowers into institutional enemies and punishes them, and (3) thereby fails to provide an ethical environment. The authors present and discuss cases of academic medicine failing to address unethical behaviour in academic science and, thereby, illustrate the scope and seriousness of the problem. The Olivieri/Apotex affair is just another instance of academic medicine's dereliction in a case of scientific fraud and misconduct. Instead of vigorously supporting their faculty member in her efforts to honestly communicate her findings and to protect patients from the risks associated with the use of the study drug, the University of Toronto collaborated with the Apotex company's "stalling tactics," closed down Dr Olivieri's laboratory, harassed her, and ultimately dismissed her. The authors argue that the incentives for addressing problematic behaviour have to be revised in order to effect a change in the current pattern of response that occurs in academic medicine. An externally imposed realignment of incentives could convert the perception of the whistleblower, from their present caste as the enemy within, into a new position, as valued friend of the institution. The authors explain how such a correction could encourage appropriate reactions to scientific misconduct from academic medicine.

  7. Academic Motivations and Academic Self-Efficacy of Nursing Students

    OpenAIRE

    Gamze Sarikoc

    2017-01-01

    Aim: Academic motivation and academic self-efficacy play important roles in the learning process. They increase academic achievement and the attainment of educational goals, thus providing opportunities in the training of qualified nurses. This study was conducted to determine nursing students%u2019 academic motivation and academic self-efficacy levels. Material and Method: This is a descriptive study. A total of 346 students who are attending a nursing school as either a first, second, third...

  8. Decisions reduce sensitivity to subsequent information.

    Science.gov (United States)

    Bronfman, Zohar Z; Brezis, Noam; Moran, Rani; Tsetsos, Konstantinos; Donner, Tobias; Usher, Marius

    2015-07-07

    Behavioural studies over half a century indicate that making categorical choices alters beliefs about the state of the world. People seem biased to confirm previous choices, and to suppress contradicting information. These choice-dependent biases imply a fundamental bound of human rationality. However, it remains unclear whether these effects extend to lower level decisions, and only little is known about the computational mechanisms underlying them. Building on the framework of sequential-sampling models of decision-making, we developed novel psychophysical protocols that enable us to dissect quantitatively how choices affect the way decision-makers accumulate additional noisy evidence. We find robust choice-induced biases in the accumulation of abstract numerical (experiment 1) and low-level perceptual (experiment 2) evidence. These biases deteriorate estimations of the mean value of the numerical sequence (experiment 1) and reduce the likelihood to revise decisions (experiment 2). Computational modelling reveals that choices trigger a reduction of sensitivity to subsequent evidence via multiplicative gain modulation, rather than shifting the decision variable towards the chosen alternative in an additive fashion. Our results thus show that categorical choices alter the evidence accumulation mechanism itself, rather than just its outcome, rendering the decision-maker less sensitive to new information. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  9. Mental imagery affects subsequent automatic defense responses

    Directory of Open Access Journals (Sweden)

    Muriel A Hagenaars

    2015-06-01

    Full Text Available Automatic defense responses promote survival and appropriate action under threat. They have also been associated with the development of threat-related psychiatric syndromes. Targeting such automatic responses during threat may be useful in populations with frequent threat exposure. Here, two experiments explored whether mental imagery as a pre-trauma manipulation could influence fear bradycardia (a core characteristic of freezing during subsequent analogue trauma (affective picture viewing. Image-based interventions have proven successful in the treatment of threat-related disorders, and are easily applicable. In Experiment 1 43 healthy participants were randomly assigned to an imagery script condition. Participants executed a passive viewing task with blocks of neutral, pleasant and unpleasant pictures after listening to an auditory script that was either related (with a positive or a negative outcome or unrelated to the unpleasant pictures from the passive viewing task. Heart rate was assessed during script listening and during passive viewing. Imagining negative related scripts resulted in greater bradycardia (neutral-unpleasant contrast than imagining positive scripts, especially unrelated. This effect was replicated in Experiment 2 (N = 51, again in the neutral-unpleasant contrast. An extra no-script condition showed that bradycardia was not induced by the negative related script, but rather that a positive script attenuated bradycardia. These preliminary results might indicate reduced vigilance after unrelated positive events. Future research should replicate these findings using a larger sample. Either way, the findings show that highly automatic defense behavior can be influenced by relatively simple mental imagery manipulations.

  10. Communicating hydrocephalus subsequent to purulent meningitis

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Ogawa, Kimio; Hibio, Shuichi; Goto, Kazuhiko; Shiihara, Hiroaki

    1984-01-01

    Based on CT findings one year after shunting, ventricular dialtion was classified into five degrees for examining prognosis of communicating hydrocephalus subsequent to purulent meningitis. Factors causing and aggravating hydrocephalus were also examined. Patients with hydrocephalus tended to have spasms frequently as the first symptom within one month after birth when there were few characteristic findings. Spasm and disturbance of consciousness occurred frequently during the first week of the occurrence of disease. Large numbers of cells in the spinal fluid and high volume of spinal cord protein were persistent in patients aged one month or less. Chloride transport decreased in patients aged two months or more. The occurrence of syndrome of the pyramidal tract, eye symptoms, movement of head to the left and right, and involuntary movement suggested serious conditions of the disease. Disturbance of movement could be relieved by giving adequate antibiotics as soon as meningitis was discovered within one month after birth and by giving chloramphenicol when symptoms suggesting the development of serious conditions occurred. However, mental retardation and epilepsy could not be prevented. (Namekawa, K.)

  11. Compressed Subsequence Matching and Packed Tree Coloring

    DEFF Research Database (Denmark)

    Bille, Philip; Cording, Patrick Hagge; Gørtz, Inge Li

    2017-01-01

    We present a new algorithm for subsequence matching in grammar compressed strings. Given a grammar of size n compressing a string of size N and a pattern string of size m over an alphabet of size \\(\\sigma \\), our algorithm uses \\(O(n+\\frac{n\\sigma }{w})\\) space and \\(O(n+\\frac{n\\sigma }{w}+m\\log N\\log...... w\\cdot occ)\\) or \\(O(n+\\frac{n\\sigma }{w}\\log w+m\\log N\\cdot occ)\\) time. Here w is the word size and occ is the number of minimal occurrences of the pattern. Our algorithm uses less space than previous algorithms and is also faster for \\(occ=o(\\frac{n}{\\log N})\\) occurrences. The algorithm uses...... a new data structure that allows us to efficiently find the next occurrence of a given character after a given position in a compressed string. This data structure in turn is based on a new data structure for the tree color problem, where the node colors are packed in bit strings....

  12. Cough during infancy and subsequent childhood asthma.

    Science.gov (United States)

    Oren, E; Rothers, J; Stern, D A; Morgan, W J; Halonen, M; Wright, A L

    2015-09-01

    Wheezing in infancy has been associated with subsequent asthma, but whether cough similarly influences asthma risk has been little studied. We sought to determine whether prolonged cough and cough without cold in the first year of life are associated with childhood asthma. Participants in the Infant Immune Study, a non-selected birth cohort, were surveyed 7 times in the first 9 months of life regarding the presence of wheeze and cough. Cough for more than 28 days was defined as prolonged. Parents were asked at 1 year if the child ever coughed without a cold. Asthma was defined as parental report of physician diagnosis of asthma, with symptoms or medication use between 2 and 9 years. Logistic regression was used to assess adjusted odds for asthma associated with cough characteristics. A total of 24% (97) of children experienced prolonged cough and 23% (95) cough without cold in the first 9 months, respectively. Prolonged cough was associated with increased risk of asthma relative to brief cough (OR 3.57, CI: 1.88, 6.76), with the risk being particularly high among children of asthmatic mothers. Cough without cold (OR 3.13, 95% CI: 1.76, 5.57) was also independently associated with risk of childhood asthma. Both relations persisted after adjustment for wheeze and total IgE at age 1. Prolonged cough in infancy and cough without cold are associated with childhood asthma, independent of infant wheeze. These findings suggest that characteristics of cough in infancy are early markers of asthma susceptibility, particularly among children with maternal asthma. © 2015 John Wiley & Sons Ltd.

  13. Factors Influencing American Plastic Surgery Residents Toward an Academic Career.

    Science.gov (United States)

    Chetta, Matthew D; Sugg, Kristoffer B; Diaz-Garcia, Rafael J; Kasten, Steven J

    2018-02-01

    Plastic surgery residency program directors have an interest in recruiting applicants who show an interest in an academic practice. Medical school achievements (ie, United States Medical Licensing Examination® scores, publications, and Alpha Omega Alpha status) are metrics assessed to grade applicants but may not correlate with ultimately choosing an academic career. This study was designed to investigate factors influencing residents' choices for or against academic careers. A 25-item online questionnaire was designed to measure baseline interest in academic plastic surgery and factors that influence decisions to continue on or abandon that career path. This questionnaire was disseminated to the integrated/combined plastic surgery residents during the 2013 to 2014 academic year. One hundred twenty-five respondents indicated that they were currently interested in pursuing academic practice (n = 78) or had lost interest in academic practice (n = 47). Among all respondents, 92.8% (n = 116) stated they were interested in academic careers at the time of residency application, but one-third (n = 41) subsequently lost interest. Those residents who retained interest in academic careers indicated resident/medical student educational opportunities (57%) and complexity of patients (52%) as reasons. Those who lost interest cited a lack of autonomy (43%), publishing requirements (32%), and income discrepancy (26%) as reasons. Many residents report losing interest in academics during residency. Traditional metrics valued in the recruitment process may not serve as positive predictors of an academic career path. Reasons why residents lose interest are not easily correctable, but mentorship, adequate career counseling, and research opportunities during training remain factors that can be addressed across all residency programs.

  14. Academic Procrastination on Worker Students

    OpenAIRE

    Muzaqi, Sugito; Arumsari, Andini Dwi

    2017-01-01

    Academic procrastination is to delay the work in the academic field. Academic procrastination occurs because students who work less able to divide his time well, between work and college. Students who work doing academic procrastination because it is less able to regulate themselves. Self-regulation is the ability to control their own behavior and one of the prime movers of the human personality. In the process of self-regulation, academic procrastination students who need to understand the i...

  15. Undisciplined beginnings, academic success, and discursive psychology.

    Science.gov (United States)

    Billig, Michael

    2012-09-01

    This paper reflects on the conditions under which Discourse and social psychology, Common knowledge, and the author's Arguing and thinking were written. These books, which were independently conceived, were not specifically written as contributions to 'discursive psychology', for discursive psychology did not exist at that time. Their authors were rejecting conventional approaches to doing psychological research. The paper discusses what it takes for a new academic movement, such as discursive psychology, to be successfully established in the current climate of 'academic capitalism'. Two requirements are particularly mentioned: the necessity for a label and the necessity for adherents to be recruited. Of the three books, only Discourse and social psychology was outwardly recruiting its readers to a new way of doing social psychology. Arguing and thinking, with its celebration of ancient rhetoric, was much more ambiguous in its aims. It was turning away from present usefulness towards the past. By claiming to be 'an antiquarian psychologist' the author was rejecting disciplinary thinking. The paper also considers the intellectual costs of establishing a new specialism or sub-discipline. The 'first generation' may have freedom, but success can bring about a narrowing of perspectives and the development of orthodoxies for subsequent academic generations. This applies as much to the development of experimental social psychology as to discursive psychology. These processes are particular enhanced in the present socio-economic situation of contemporary universities, which make it more difficult for young academics to become, in the words of William James, 'undisciplinables'. ©2012 The British Psychological Society.

  16. Relations of Perceived Maternal Parenting Style, Practices, and Learning Motivation to Academic Competence in Chinese Children

    Science.gov (United States)

    Cheung, Cecilia S.; McBride-Chang, Catherine

    2008-01-01

    A measure of academic parenting practices was developed through parent and teacher interviews and subsequently administered to 91 Hong Kong Chinese fifth graders, who also rated their mothers' restrictiveness and concern, school motivation, and self-perceived academic competence. Children's actual school grades were obtained from school records.…

  17. Whistleblowing in academic medicine

    Science.gov (United States)

    Rhodes, R; Strain, J

    2004-01-01

    The authors present and discuss cases of academic medicine failing to address unethical behaviour in academic science and, thereby, illustrate the scope and seriousness of the problem. The Olivieri/Apotex affair is just another instance of academic medicine's dereliction in a case of scientific fraud and misconduct. Instead of vigorously supporting their faculty member in her efforts to honestly communicate her findings and to protect patients from the risks associated with the use of the study drug, the University of Toronto collaborated with the Apotex company's "stalling tactics," closed down Dr Olivieri's laboratory, harassed her, and ultimately dismissed her. The authors argue that the incentives for addressing problematic behaviour have to be revised in order to effect a change in the current pattern of response that occurs in academic medicine. An externally imposed realignment of incentives could convert the perception of the whistleblower, from their present caste as the enemy within, into a new position, as valued friend of the institution. The authors explain how such a correction could encourage appropriate reactions to scientific misconduct from academic medicine. PMID:14872069

  18. CAEP 2015 Academic Symposium: Leadership within the emergency medicine academic community and beyond.

    Science.gov (United States)

    Sinclair, Doug; Worthington, James R; Joubert, Gary; Holroyd, Brian R; Stempien, James; Letovsky, Eric; Rutledge, Tim; LeBlanc, Constance; Pitters, Carrol; McCallum, Andrew; Carr, Brendan; Gerace, Rocco; Stiell, Ian G; Artz, Jennifer D; Christenson, Jim

    2016-05-01

    A panel of emergency medicine (EM) leaders endeavoured to define the key elements of leadership and its models, as well as to formulate consensus recommendations to build and strengthen academic leadership in the Canadian EM community in the areas of mentorship, education, and resources. The expert panel comprised EM leaders from across Canada and met regularly by teleconference over the course of 9 months. From the breadth of backgrounds and experience, as well as a literature review and the development of a leadership video series, broad themes for recommendations around the building and strengthening of EM leadership were presented at the CAEP 2015 Academic Symposium held in Edmonton, Alberta. Feedback from the attendees (about 80 emergency physicians interested in leadership) was sought. Subsequently, draft recommendations were developed by the panel through attendee feedback, further review of the leadership video series, and expert opinion. The recommendations were distributed to the CAEP Academic Section for further feedback and updated by consensus of the expert panel. The methods informed the panel who framed recommendations around four themes: 1) leadership preparation and training, 2) self-reflection/emotional intelligence, 3) academic leadership skills, and 4) gender balance in academic EM leadership. The recommendations aimed to support and nurture the next generation of academic EM leaders in Canada and included leadership mentors, availability of formal educational courses/programs in leadership, self-directed education of aspiring leaders, creation of a Canadian subgroup with the AACEM/SAEM Chair Development Program, and gender balance in leadership roles. These recommendations serve as a roadmap for all EM leaders (and aspiring leaders) to build on their success, inspire their colleagues, and foster the next generation of Canadian EM academic leaders.

  19. Personality, Academic Self-Efficacy, Academic Locus of Control and Academic Procrastination Among University Students

    OpenAIRE

    Yazıcı, Hikmet; Albayrak, Elif; Reisoğlu, Serpil

    2016-01-01

    There are several variables to determine academic procrastination behavior among university students. The main aim of the present study was to investigate the relationships among big five personality, academic self-efficacy, academic locus of control and academic procrastination. Research group consisted of 885 university students (Female=496, Male=389) in 2012/2013 academic year in Karadeniz Technical University. Results from study indicated that responsibility and amenability subscales of b...

  20. Academic Training: 2004 - 2005 ACADEMIC TRAINING PROGRAMME

    CERN Multimedia

    Françoise Benz

    2004-01-01

    1st Term - 01 October to 17 December 2004 REGULAR LECTURE PROGRAMME New Trends in Fusion Research by A. Fasoli, EPFL, Lausanne, CH 11, 12, 13 October Physics at e+e- linear collider by K. Desch, DESY, Hamburg, D 15, 16, 17, 18, 19 November LECTURE SERIES FOR POSTGRADUATE STUDENTS Standard Model by R. Barbieri, CERN-PH-TH 6, 7, 8, 9 10 December The lectures are open to all those interested, without application. The abstract of the lectures, as well as any change to the above information (title, dates, time, place etc) will be published in the CERN Bulletin, the WWW, and by notices before each term and for each series of lectures. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form a...

  1. Academic Training: 2003 - 2004 Academic Training Programme

    CERN Multimedia

    2004-01-01

    ACADEMIC TRAINING Françoise Benz tel. 73127 academic.training@cern.ch 3rd Term - 5 April to 2nd July 2004 REGULAR LECTURE PROGRAMME 19, 20, 21, 22, 23 April Complex Systems, Chaos and Measurements by P. Collet / Ecole Polytechnique, Palaiseau, France 26, 27, 28, 29 April The Theory of Heavy Ion Collisions by U. Wiedemann / CERN-PH/TH 10, 11, 12, 13, 14 May Particle Identification at the LHC by D. Fournier / LAL, Orsay, France 1, 2, 3, 4 June Neural Systems, Genetic Algorithms by V. Robles Forcada and M. Perez Hernandez / Univ. Politecnica de Madrid E. 7, 8, 9, June Real Time Process Control by T. Riesco / CERN-TS 14, 15, 16, 17, 18 June The Cosmic Microwave Background by M. Zaldarriaga / Harvard University, USA 21, 22, 23, June Fixed Target Physics at CERN : Results and Prospects by J. Engelen / CERN-DG 28, 29, 30 June, 1, 2, July Search for Dark Matter by B. Sadoulet / Univ. of California, Berkeley, USA The lectures are open to all those interested, without application. The abstrac...

  2. Bioethics and academic freedom.

    Science.gov (United States)

    Singer, Peter

    1990-01-01

    The author describes the events surrounding his attempts to lecture on the subject of euthanasia in West Germany in June 1989. Singer, who defends the view that active euthanasia for some newborns with handicaps may be ethically permissible, had been invited to speak to professional and academic groups. Strong public protests against Singer and his topic led to the cancellation of some of his engagements, disruptions during others, and harrassment of the German academics who had invited him to speak. These incidents and the subject of euthanasia became matters of intense national debate in West Germany, but there was little public or academic support for Singer's right to be heard. Singer argues that bioethics and bioethicists must have the freedom to challenge conventional moral beliefs, and that the events in West Germany illustrate the grave danger to that freedom from religious and political intolerance.

  3. Joint Contributions of Peer Acceptance and Peer Academic Reputation to Achievement in Academically At-Risk Children: Mediating Processes

    Science.gov (United States)

    Chen, Qi; Hughes, Jan N.; Liew, Jeffrey; Kwok, Oi-Man

    2010-01-01

    The longitudinal relationships between two dimensions of peer relationships and subsequent academic adjustment were investigated in a sample of 543 relatively low achieving children (M = 6.57 years at Year 1, 1st grade). Latent variable SEM was used to test a four stage model positing indirect effects of peer acceptance and peer academic…

  4. Exercise Equipment: Neutral Buoyancy

    Data.gov (United States)

    National Aeronautics and Space Administration — Axial skeletal loads coupled with muscle forces maintain bone in the spine and lower extremities during International Space Station (ISS) missions. Current exercise...

  5. Buoyancy Can-Can

    Science.gov (United States)

    Nelson, Jim; Nelson, Jane Bray

    2015-01-01

    In this paper, a discrepant event is used to initiate a learning cycle lesson to help students develop an understanding of the concept and equation for buoyant force. The data are gathered using readily available equipment and then graphically analyzed using a four-step analysis consistent with the modeling instructional approach. This laboratory…

  6. #IWD2016 Academic Inspiration

    DEFF Research Database (Denmark)

    Meier, Ninna

    2016-01-01

    What academics or books have inspired you in your writing and research, or helped to make sense of the world around you? In this feature essay, Ninna Meier returns to her experience of reading Hannah Arendt as she sought to understand work and how it relates to value production in capitalist...... economies. Meier recounts how Arendt’s book On Revolution (1963) forged connective threads between the ‘smallest parts’ and the ‘largest wholes’ and showed how academic work is never fully relegated to the past, but can return in new iterations across time....

  7. Academic Culture and Campus Culture of Universities

    Science.gov (United States)

    Shen, Xi; Tian, Xianghong

    2012-01-01

    Academic culture of universities mainly consists of academic outlooks, academic spirits, academic ethics and academic environments. Campus culture in a university is characterized by individuality, academic feature, opening, leading, variety and creativity. The academic culture enhances the construction of campus culture. The campus culture…

  8. Productive procrastination: academic procrastination style predicts academic and alcohol outcomes

    Science.gov (United States)

    Westgate, Erin C.; Wormington, Stephanie V.; Oleson, Kathryn C.; Lindgren, Kristen P.

    2017-01-01

    Productive procrastination replaces one adaptive behavior with another adaptive—albeit less important—behavior (e.g., organizing notes instead of studying for an exam). We identified adaptive and maladaptive procrastination styles associated with academic and alcohol outcomes in 1106 college undergraduates. Cluster analysis identified five academic procrastination styles—non-procrastinators, academic productive procrastinators, non-academic productive procrastinators, non-academic procrastinators, and classic procrastinators. Procrastination style differentially predicted alcohol-related problems, cravings, risk of alcohol use disorders, and GPA (all ps procrastination and academic productive procrastination were most adaptive overall; non-academic productive procrastination, non-academic procrastination, and classic procrastination were least adaptive. Productive procrastination differed from other procrastination strategies, and maladaptive procrastination styles may be a useful risk indicator for preventative and intervention efforts. PMID:28804158

  9. Academic interventions for academic procrastination: A review of the literature.

    Science.gov (United States)

    Zacks, Shlomo; Hen, Meirav

    2018-01-01

    Procrastination is a widespread phenomenon in academic settings. It has been studied from many different theoretical angles, and a variety of causes and consequences have been suggested. Recent studies support the notion that academic procrastination can be seen from a situational perspective and as a failure in learning self-regulation. It suggests that interventions should address situational as well as deficits in self-regulation to help students overcome their procrastinating tendencies. The present review examined the recent literature on causes and consequences of academic procrastination and the limited number of studies of academic interventions for academic procrastination. Findings of this review strengthen the need to further study the topic of academic interventions for academic procrastination and to develop effective interventions. At the end of this review, several suggestions for the development of academic interventions are outlined.

  10. Productive procrastination: academic procrastination style predicts academic and alcohol outcomes.

    Science.gov (United States)

    Westgate, Erin C; Wormington, Stephanie V; Oleson, Kathryn C; Lindgren, Kristen P

    2017-03-01

    Productive procrastination replaces one adaptive behavior with another adaptive-albeit less important-behavior (e.g., organizing notes instead of studying for an exam). We identified adaptive and maladaptive procrastination styles associated with academic and alcohol outcomes in 1106 college undergraduates. Cluster analysis identified five academic procrastination styles- non-procrastinators , academic productive procrastinators , non-academic productive procrastinators, non-academic procrastinators , and classic procrastinators . Procrastination style differentially predicted alcohol-related problems, cravings, risk of alcohol use disorders, and GPA (all ps procrastination and academic productive procrastination were most adaptive overall; non-academic productive procrastination, non-academic procrastination, and classic procrastination were least adaptive. Productive procrastination differed from other procrastination strategies, and maladaptive procrastination styles may be a useful risk indicator for preventative and intervention efforts.

  11. Academic Nightmares: Predatory Publishing

    Science.gov (United States)

    Van Nuland, Sonya E.; Rogers, Kem A.

    2017-01-01

    Academic researchers who seek to publish their work are confronted daily with a barrage of e-mails from aggressive marketing campaigns that solicit them to publish their research with a specialized, often newly launched, journal. Known as predatory journals, they often promise high editorial and publishing standards, yet their exploitive business…

  12. Academic Work and Performance

    Science.gov (United States)

    Gunter, Helen M.

    2012-01-01

    Reading current accounts of higher education demonstrates the flux and damage of rapid neoliberal changes to the type and conduct of academic work. Opening the Times Higher Education magazine on the 28 April 2011 shows articles about cuts in staffing and undergraduate provision in England, concerns about the quality of for-profit higher education…

  13. On Academic Boredom

    Science.gov (United States)

    Baghdadchi, Amir

    2005-01-01

    The kind of boredom experienced in academia is unique. Neither a purely subjective nor objective phenomenon, it is the product of the way research is organized into papers, seminars, and conferences, as well as of a deep implicit metaphor that academic argument is a form of warfare. In this respect, the concepts of boredom and rigour are closely…

  14. Towards Transnational Academic Capitalism

    Science.gov (United States)

    Kauppinen, Ilkka

    2012-01-01

    This paper contributes to current debates on the relationship between globalisation and higher education. The main argument of the paper is that we are currently witnessing transnationalisation of academic capitalism. This argument is illustrated by examining the collaboration between transnational corporations and research universities, and how…

  15. Kompetenceprofil for academic developers

    DEFF Research Database (Denmark)

    Troelsen, Rie; Mørcke, Anne Mette

    gerne vil udføre? Vi vil også diskutere hvilke positive og negative konsekvenser en (mulig fælles nordisk) kompetenceprofil kunne få.Referencer:Ansela, M. & Maikkola, M. (2007). ACADEMIC DEVELOPER’S COMPETENCE-BASED DESCRIPTION:Core and basic competences. Retrieved 22/01/15 at http://www.peda-forum.fi/index.php...

  16. Academic Vocational Training

    DEFF Research Database (Denmark)

    Willert, Søren; Keller, Hanne Dauer; Stegeager, Nikolaj

    2010-01-01

    Danish society puts a high value on education which is traditionally seen as a crucial vehicle for development in all spheres of social and economic life. Large sums are spent on work-related adult learning, an important example being academically based masters programs. Yet, the actual effects o......, with examples, a framework for designing educational programs which can help make academic teaching relevant to production-oriented life in organizations. The paper may be read as a statement from which criteria for evaluating the said masters programs can be generated.......Danish society puts a high value on education which is traditionally seen as a crucial vehicle for development in all spheres of social and economic life. Large sums are spent on work-related adult learning, an important example being academically based masters programs. Yet, the actual effects...... of such educational investment in terms of improved workplace efficiency remain obscure both with respect to the organization and the individual. Academically acquired knowledge is generally admitted not to affect work-related outcomes to any significant extent. The three authors of this paper are all involved...

  17. Signals: Applying Academic Analytics

    Science.gov (United States)

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  18. Participatory academic communities

    DEFF Research Database (Denmark)

    Aaen, Janus Holst; Nørgård, Rikke Toft

    2015-01-01

    understanding of participation in edu-cation can move educatees’ learning beyond institutions through focusing on educatees as researchers, participat-ing in society, building a research community and obtaining academic citizenship. Further, the article discusses how a value-based, vision-driven approach...

  19. Correlates of Academic Procrastination.

    Science.gov (United States)

    Milgram, Norman A.; And Others

    1993-01-01

    Investigated concurrent correlates of academic procrastination in Israeli college preparatory students (n=113). Procrastination in one course of study was found to be moderately correlated with procrastination in another but not to procrastination in routine tasks of daily living. Procrastination was weakly related to emotional upset about it and…

  20. Academic Drug Discovery Centres

    DEFF Research Database (Denmark)

    Kirkegaard, Henriette Schultz; Valentin, Finn

    2014-01-01

    Academic drug discovery centres (ADDCs) are seen as one of the solutions to fill the innovation gap in early drug discovery, which has proven challenging for previous organisational models. Prior studies of ADDCs have identified the need to analyse them from the angle of their economic...

  1. Academic streaming in Europe

    DEFF Research Database (Denmark)

    Falaschi, Alessandro; Mønster, Dan; Doležal, Ivan

    2004-01-01

    The TF-NETCAST task force was active from March 2003 to March 2004, and during this time the mem- bers worked on various aspects of streaming media related to the ultimate goal of setting up common services and infrastructures to enable netcasting of high quality content to the academic community...

  2. Measuring faculty retention and success in academic medicine.

    Science.gov (United States)

    Ries, Andrew; Wingard, Deborah; Gamst, Anthony; Larsen, Catherine; Farrell, Elizabeth; Reznik, Vivian

    2012-08-01

    To develop and demonstrate the usefulness of quantitative methods for assessing retention and academic success of junior faculty in academic medicine. The authors created matched sets of participants and nonparticipants in a junior faculty development program based on hire date and academic series for newly hired assistant professors at the University of California, San Diego (UCSD), School of Medicine between 1988 and 2005. They used Kaplan-Meier and Cox proportional hazards survival analyses to characterize the influence of covariates, including gender, ethnicity, and program participation, on retention. They also developed a new method for quantifying academic success based on several measures including (1) leadership and professional activities, (2) honors and awards, (3) research grants, (4) teaching and mentoring/advising activities, and (5) publications. The authors then used these measures to compare matched pairs of participating and nonparticipating faculty who were subsequently promoted and remained at UCSD. Compared with matched nonparticipants, the retention of junior faculty who participated in the faculty development program was significantly higher. Among those who were promoted and remained at UCSD, the academic success of faculty development participants was consistently greater than that of matched nonparticipants. This difference reached statistical significance for leadership and professional activities. Using better quantitative methods for evaluating retention and academic success will improve understanding and research in these areas. In this study, use of such methods indicated that organized junior faculty development programs have positive effects on faculty retention and may facilitate success in academic medicine.

  3. Personal factors that influence deaf college students' academic success.

    Science.gov (United States)

    Albertini, John A; Kelly, Ronald R; Matchett, Mary Karol

    2012-01-01

    Research tells us that academic preparation is key to deaf students' success at college. Yet, that is not the whole story. Many academically prepared students drop out during their first year. This study identified entering deaf college students' personal factors as assessed by their individual responses to both the Noel-Levitz College Student Inventory Form B and the Learning and Study Strategies Inventory, second edition (LASSI). Entering students in 3 successive cohorts (total n =437) participated in this study. Results show that in addition to entry measurements of reading and mathematic skills, personal factors contributed to the academic performance of students in their first quarter in college. The Noel-Levitz provided the comparatively better predictive value of academic performance: Motivation for Academic Study Scale (e.g., desire to finish college). The LASSI also showed statistically significant predictors, the Self-Regulation Component (e.g., time management) and Will Component (e.g., self-discipline), but accounted for relatively less variability in the students' initial grade point averages. For this group of underprepared students, results show that personal factors can play a significant role in academic success. Deaf students' personal factors are discussed as they relate to other first-year college students and to their subsequent academic performance and persistence.

  4. Summary of Research 1997, Interdisciplinary Academic Groups

    National Research Council Canada - National Science Library

    Boger, Dan

    1999-01-01

    This report contains information of research projects in the interdisciplinary groups, Command, Control, and Communications Academic Group, Information Warfare Academic Group, Space Systems Academic...

  5. Why Do Academics Use Academic Social Networking Sites?

    Science.gov (United States)

    Meishar-Tal, Hagit; Pieterse, Efrat

    2017-01-01

    Academic social-networking sites (ASNS) such as Academia.edu and ResearchGate are becoming very popular among academics. These sites allow uploading academic articles, abstracts, and links to published articles; track demand for published articles, and engage in professional interaction. This study investigates the nature of the use and the…

  6. The Effect of Academic Advising on Academic Performance of ...

    African Journals Online (AJOL)

    Although academic advising in Kenyan universities exists, no research has been done to find out how it impacts on students' educational and career goals. This research aimed at establishing the effect of academic advising on academic performance and the influence of year of study and gender on students' tendency to ...

  7. Is Your Academic Library Pinning? Academic Libraries and Pinterest

    Science.gov (United States)

    Thornton, Elaine

    2012-01-01

    Academic libraries are flocking to online social networking sites in an effort to meet users where they are. Pinterest is the latest of these rapidly growing online social networking tools. The author of this article reports results from a survey on academic libraries' presence on Pinterest. The survey found most academic library pinboards are in…

  8. Influence of radiation on predictive accuracy in numerical simulations of the thermal environment in industrial buildings with buoyancy-driven natural ventilation

    International Nuclear Information System (INIS)

    Meng, Xiaojing; Wang, Yi; Liu, Tiening; Xing, Xiao; Cao, Yingxue; Zhao, Jiangping

    2016-01-01

    Highlights: • The effects of radiation on predictive accuracy in numerical simulations were studied. • A scaled experimental model with a high-temperature heat source was set up. • Simulation results were discussed considering with and without radiation model. • The buoyancy force and the ventilation rate were investigated. - Abstract: This paper investigates the effects of radiation on predictive accuracy in the numerical simulations of industrial buildings. A scaled experimental model with a high-temperature heat source is set up and the buoyancy-driven natural ventilation performance is presented. Besides predicting ventilation performance in an industrial building, the scaled model in this paper is also used to generate data to validate the numerical simulations. The simulation results show good agreement with the experiment data. The effects of radiation on predictive accuracy in the numerical simulations are studied for both pure convection model and combined convection and radiation model. Detailed results are discussed regarding the temperature and velocity distribution, the buoyancy force and the ventilation rate. The temperature and velocity distributions through the middle plane are presented for the pure convection model and the combined convection and radiation model. It is observed that the overall temperature and velocity magnitude predicted by the simulations for pure convection were significantly greater than those for the combined convection and radiation model. In addition, the Grashof number and the ventilation rate are investigated. The results show that the Grashof number and the ventilation rate are greater for the pure convection model than for the combined convection and radiation model.

  9. Buoyancy-Driven Ventilation Generated by the Double-Skin Façade of a High-Rise Building in Tropical Climate: Case Study Bandung, Indonesia

    Directory of Open Access Journals (Sweden)

    Aziiz Akhlish Diinal

    2017-01-01

    Full Text Available High-rise buildings in tropical region is identical to the use of mechanical Air Conditioning in massive scale. Nevertheless, there is an encouragement to high-rise buildings to reduce its energy consumptions, since they consume quite large amount of energy. This challenge can be overcome with various of strategies, one of them, by means of reducing the cooling load of mechanical Air Conditioning in high-rise building. Prospects come from the modern tall building design strategies, for example the use of double-skin façade to give addition of building skin which could provide indoor temperature protection from outside. Double-skin façade system has continued to increase in buildings in a tropical region such as in Indonesia. However, there is another potential of double skin façade, which is the possibility to increase the buoyancy effect in the air gap between the skin and building envelope. The possibility needs to be studied in order to give a proper way in designing double-skin façade of a high-rise building, especially on Bandung-Indonesia tropical climate. This paper explores the potential of double-skin façade in driving the air inside the façade to generate natural ventilation for a high-rise building in Bandung climate condition. Two parameters are used in exploring the buoyancy force, the width of double-skin façade and the temperature of the skin façade. In general, double-skin façade of a high-rise building in tropical climate can generate buoyancy driven ventilation for the building, it relates strongly to the distance between of the double-skin façade and the building envelope.

  10. Pancreatin-EDTA treatment affects buoyancy of cells in Cohn fraction V protein density gradients without residual effect on cell size.

    Science.gov (United States)

    Sheridan, J W; Simmons, R J

    1983-12-01

    The buoyancy of suspension-grown Mastocytoma P815 X-2 cells in albumin-rich Cohn fraction V protein (CFVP) density gradients was found to be affected by prior incubation of the cells in pancreatin-EDTA salt solution. Whereas in pH 5.2 CFVP, pancreatin-EDTA treated cells behaved as if of reduced density when compared with the control 'undigested' group, in pH 7.3 CFVP they behaved as if of increased density. By contrast, pancreatin-EDTA treatment had no effect on the buoyancy of mastocytoma cells in polyvinylpyrrolidone-coated colloidal silica (PVP-CS, Percoll T.M.) density gradients of either pH 5.2 or pH 7.3. As cell size determinations failed to reveal alterations in cell size either as a direct result of pancreatin-EDTA treatment or as a combined consequence of such treatment and exposure to CFVP either with or without centrifugation, a mechanism involving a change in cell density other than during the centrifugation process itself seems unlikely. Binding studies employing 125I-CFVP, although indicating that CFVP bound to cells at 4 degrees, failed to reveal a pancreatin-EDTA treatment-related difference in the avidity of this binding. Although the mechanism of the pancreatin-EDTA-induced buoyancy shift in CFVP remains obscure, the absence of such an effect in PVP-CS suggests that the latter cell separation solution may more accurately be used to determine cell density.

  11. Running continuous academic adoption programmes

    DEFF Research Database (Denmark)

    Nielsen, Tobias Alsted

    Running successful academic adoption programmes requires executive support, clear strategies, tactical resources and organisational agility. These two presentations will discuss the implementation of strategic academic adoption programs down to very concrete tool customisations to meet specific...

  12. Physical Activity and Academic Achievement

    Centers for Disease Control (CDC) Podcasts

    This podcast highlights the evidence that supports the link between physical activity and improved academic achievement. It also identifies a few actions to support a comprehensive school physical activity program to improve academic achievement.

  13. Healthy Eating and Academic Achievement

    Centers for Disease Control (CDC) Podcasts

    This podcast highlights the evidence that supports the link between healthy eating and improved academic achievement. It also identifies a few actions to support a healthy school nutrition environment to improve academic achievement.

  14. Integrated Factors Correlating Undergraduate Academic ...

    African Journals Online (AJOL)

    Integrated Factors Correlating Undergraduate Academic Achievement in Bayelsa State, Nigeria. ... AFRREV IJAH: An International Journal of Arts and Humanities ... Thus, it is study investigated the integrated factors determining academic performance of students in public secondary schools in Bayelsa State, Nigeria.

  15. 29 CFR 18.407 - Subsequent remedial measures.

    Science.gov (United States)

    2010-07-01

    ... OFFICE OF ADMINISTRATIVE LAW JUDGES Rules of Evidence Relevancy and Its Limits § 18.407 Subsequent... event less likely to occur, evidence of the subsequent measures is not admissible to prove negligence or...

  16. Academic capitalism and academic culture: A case study.

    Directory of Open Access Journals (Sweden)

    Pilar Mendoza

    2008-12-01

    Full Text Available This case study investigated the impact of academic capitalism on academic culture by examining the perspectives of faculty members in an American academic department with significant industrial funding. The results of this study indicate that faculty members believe that the broad integrity of the academic culture remains unaffected in this department and they consider industrial sponsorship as a highly effective vehicle for enhancing the quality of education of students and pursuing their scientific interests. This study provides valuable insights to federal and institutional policiescreated to foster industry-academia partnerships and commercialization of academic research.

  17. Another Discussion about Academic Corruption

    Science.gov (United States)

    Changgeng, Li

    2007-01-01

    Academic corruption is a commonplace matter about which all people are clearly aware. However, people often overlook many hidden or latent manifestations of academic corruption. This article discusses eight of these manifestations: indiscriminate use of the academic team spirit, the proliferation of "word games," deliberate attacks on…

  18. Life Stress and Academic Burnout

    Science.gov (United States)

    Lin, Shu-Hui; Huang, Yun-Chen

    2014-01-01

    Stress has been shown to negatively affect learning. Academic burnout is a significant problem associated with poor academic performance. Although there has been increased attention on these two issues, literature on the relationship between students' life stress and burnout is relatively limited. This study surveys academic burnout and life…

  19. Academic Freedom Requires Constant Vigilance

    Science.gov (United States)

    Emery, Kim

    2009-01-01

    Traditionally, academic freedom has been understood as an individual right and a negative liberty. As William Tierney and Vincente Lechuga explain, "Academic freedom, although an institutional concept, was vested in the individual professor." The touchstone document on academic freedom, the American Association of University Professor's (AAUP)…

  20. Academic Freedom and Indentured Students

    Science.gov (United States)

    Williams, Jeffrey J.

    2012-01-01

    Discussion of academic freedom usually focuses on faculty, and it usually refers to speech. That is the gist of the 1915 "General Report of the Committee on Academic Freedom and Academic Tenure," appearing in the inaugural AAUP "Bulletin" as a kind of mission statement. Given the conditions of the American system of higher education--decentralized…

  1. The Constitution and Academic Freedom.

    Science.gov (United States)

    Gilbertson, Eric R.

    During the past 150 years U.S. courts have demonstrated a special protectiveness toward academics and academic institutions. Academic freedom was not a concern when the U.S. Constitution and the First Amendment were drafted and is not mentioned in the "Federalist Papers." However, decisions by a series of Supreme Court justices led to…

  2. Computer Anxiety, Academic Stress, and Academic Procrastination on College Students

    Directory of Open Access Journals (Sweden)

    Wahyu Rahardjo

    2013-01-01

    Full Text Available Academic procrastination is fairly and commonly found among college students. The lack of understanding in making the best use of computer technology may lead to anxiety in terms of operating computer hence cause postponement in completing course assignments related to computer operation. On the other hand, failure in achieving certain academic targets as expected by parents and/or the students themselves also makes students less focused and leads to tendency of postponing many completions of course assignments. The aim of this research is to investigate contribution of anxiety in operating computer and academic stress toward procrastination on students. As much as 65 students majoring in psychology became participants in this study. The results showed that anxiety in operating computer and academic stress play significant role in influencing academic procrastination among social sciences students. In terms of academic procrastination tendencies, anxiety in operating computer and academic stress, male students have higher percentage than female students.

  3. Plagiarism in Academic Texts

    Directory of Open Access Journals (Sweden)

    Marta Eugenia Rojas-Porras

    2012-08-01

    Full Text Available The ethical and social responsibility of citing the sources in a scientific or artistic work is undeniable. This paper explores, in a preliminary way, academic plagiarism in its various forms. It includes findings based on a forensic analysis. The purpose of this paper is to raise awareness on the importance of considering these details when writing and publishing a text. Hopefully, this analysis may put the issue under discussion.

  4. Academic Manager or Managed Academic? Academic Identity Schisms in Higher Education

    Science.gov (United States)

    Winter, Richard

    2009-01-01

    The relationship between values and academic identity has received scant attention in the higher education literature with some notable exceptions (Churchman, 2006; Harley, 2002; Henkel, 2005). This paper contends that the perceived need to align all academics around corporate values and goals has given rise to academic identity schisms in higher…

  5. Gender Differences in the Relationship between Academic Procrastination, Satisfaction with Academic Life and Academic Performance

    Science.gov (United States)

    Balkis, Murat; Duru, Erdinç

    2017-01-01

    Introduction: Procrastination has become one of the most researched topics due its adverse effects on the both general and student population in social sciences. The general tendency toward delaying academic tasks has been conceptualized as academic procrastination in academic setting. It is a prevalent issue among students and a numerous students…

  6. Body armour and lateral-plate reduction in freshwater three-spined stickleback Gasterosteus aculeatus: adaptations to a different buoyancy regime?

    Science.gov (United States)

    Myhre, F; Klepaker, T

    2009-11-01

    Several factors related to buoyancy were compared between one marine and two freshwater populations of three-spined stickleback Gasterosteus aculeatus. Fish from all three populations had buoyancy near to neutral to the ambient water. This showed that neither marine nor freshwater G. aculeatus used swimming and hydrodynamic lift to prevent sinking. Comparing the swimbladder volumes showed that freshwater completely plated G. aculeatus had a significantly larger swimbladder volume than both completely plated marine and low-plated freshwater G. aculeatus. Furthermore, body tissue density was lower in low-plated G. aculeatus than in the completely plated marine and freshwater fish. The results show that G. aculeatus either reduce tissue density or increase swimbladder volume to adapt to lower water density. Mass measurements of lateral plates and pelvis showed that loss of body armour in low-plated G. aculeatus could explain the tissue density difference between low-plated and completely plated G. aculeatus. This suggests that the common occurrence of plate and armour reduction in freshwater G. aculeatus populations can be an adaptation to a lower water density.

  7. Monuments to Academic Carelessness

    Science.gov (United States)

    2014-01-01

    In 1942, Katherine Frost Bruner published an article titled “Of psychological writing: Being some valedictory remarks on style.” It was published in Journal of Abnormal and Social Psychology, the journal for which she served as editorial assistant between 1937 and 1941. Her collection of advice to writing scholars has been widely quoted, including by several editions of The Publication Manual of the American Psychological Association. The most frequently quoted message in Bruner’s article deals with the importance of making sure that references in academic texts are complete and accurate. Exploring the citation history of this particular message reveals an ironic point: the great majority of those who have quoted Bruner’s words on reference accuracy have not done so accurately. The case may serve as a reminder of the importance of the basic academic principle of striving to use primary sources. The most startling finding in this study is how frequently this principle is violated, even by authors who advise and educate academic writers. PMID:28479644

  8. Administrative skills for academic physicians.

    Science.gov (United States)

    Aluise, J J; Scmitz, C C; Bland, C J; McArtor, R E

    1989-01-01

    To function effectively within the multifaceted environment of the academic medical center, academic physicians need to heighten their understanding of the economics of the health care system, and further develop their leadership and managerial skills. A literature base on organizational development and management education now exists that addresses the unique nature of the professional organization, including academic medical centers. This article describes an administration development curriculum for academic physicians. Competency statements, instructional strategies and references provide the academic physician with guidelines for expanding their professional expertise to include organizational and management skills. The continuing success of the academic medical center as a responsive health care system may depend upon the degree to which academic physicians gain sophistication in self-management and organizational administration.

  9. Leisure-Time Physical Activity and Academic Performance: Cross-Lagged Associations from Adolescence to Young Adulthood.

    Science.gov (United States)

    Aaltonen, Sari; Latvala, Antti; Rose, Richard J; Kujala, Urho M; Kaprio, Jaakko; Silventoinen, Karri

    2016-12-15

    Physical activity and academic performance are positively associated, but the direction of the association is poorly understood. This longitudinal study examined the direction and magnitude of the associations between leisure-time physical activity and academic performance throughout adolescence and young adulthood. The participants were Finnish twins (from 2,859 to 4,190 individuals/study wave) and their families. In a cross-lagged path model, higher academic performance at ages 12, 14 and 17 predicted higher leisure-time physical activity at subsequent time-points (standardized path coefficient at age 14: 0.07 (p academic performance. A cross-lagged model of co-twin differences suggested that academic performance and subsequent physical activity were not associated due to the environmental factors shared by co-twins. Our findings suggest that better academic performance in adolescence modestly predicts more frequent leisure-time physical activity in late adolescence and young adulthood.

  10. Academic workload management towards learning, components of academic work

    OpenAIRE

    Ocvirk, Aleksandra; Trunk Širca, Nada

    2013-01-01

    This paper deals with attributing time value to academic workload from the point of view of an HEI, management of teaching and an individual. We have conducted a qualitative study aimed at analysing documents on academic workload in terms of its definition, and at analysing the attribution of time value to components of academic work in relation to the proportion of workload devoted to teaching in the sense of ensuring quality and effectiveness of learning, and in relation to financial implic...

  11. Schooling Background and Academic Academic Achievement of Agricultural Students

    Directory of Open Access Journals (Sweden)

    N. Jayakumar

    2016-05-01

    Full Text Available In our society academic achievement is considered as a key criterion to judge one’s total potentiality and capability. Academic achievement is seen as a students’ grade point averages in many academic settings. Academic achievement has become an index of students’ future in this highly competitive world and Agricultural education is no exception.  Hence it becomes necessary to find out the factors that determine better academic performance. In this context the present study had been carried out to find out the possible relationship between schooling background and academic achievement of agriculture students. The students admitted in Adhiparasakthi Agricultural College, Kalavai, Vellore between 1999 and 2009 formed the subjects of the study. Findings of the study revealed that determinants like gender, type of school and stream of education had a significant role in the academic achievement of the students. Medium of instruction in HSC did influence the academic achievement but not significantly. It was also found that students who performed well in their HSC did perform well in their undergraduate programme also. This confirms that previous educational outcomes are the most important indicators of student’s future achievement and schooling background has a significant role in academic achievement of students.

  12. Academic procrastination and academic performance: An initial basis for intervention.

    Science.gov (United States)

    Goroshit, Marina

    2018-01-01

    Academic procrastination is a prevalent phenomenon with a range of negative outcomes. Many studies focused on causes and correlates of academic procrastination; however, the study of interventions for academic procrastination is scarce. The present study is an initial effort to study the relationship between academic procrastination, online course participation, and achievement, as a basis for developing an intervention for academic procrastination. Findings indicated that studying procrastination was negatively associated with final exam grade as well as with the three online course participation measures. Final exam grade was positively associated with two of the online course participation measures, and they positively correlated with each other. In addition, results indicated that studying procrastination, in combination with online course participation measures, explained about 50% of variance in final exam's grade. Frequency of activities in course Web site had the strongest positive effect on final exam's grade. These findings strengthen the notion that studying procrastination is an impediment to students' academic performance and outcomes and clarifies the need to develop and study academic interventions for academic procrastination as a means to decrease its prevalence in academic settings.

  13. The academic rat race

    DEFF Research Database (Denmark)

    Landes, Xavier; Andersen, Martin Marchman; Nielsen, Morten Ebbe Juul

    2012-01-01

    : an increased pressure to produce articles (in peer-reviewed journals) has created an unbalanced emphasis on the research criterion at the expense of the latter two. More fatally, this pressure has turned academia into a rat race, leading to a deep change in the fundamental structure of academic behaviour......, and entailing a self-defeating and hence counter-productive pattern, where more publications is always better and where it becomes increasingly difficult for researchers to keep up with the new research in their field. The article identifies the pressure to publish as a problem of collective action. It ends up...

  14. Collective academic supervision

    DEFF Research Database (Denmark)

    Nordentoft, Helle Merete; Thomsen, Rie; Wichmann-Hansen, Gitte

    2013-01-01

    Supervision of students is a core activity in higher education. Previous research on student supervision in higher education focus on individual and relational aspects in the supervisory relationship rather than collective, pedagogical and methodical aspects of the planning of the supervision...... process. This article fills these gaps by discussing potentials and challenges in “Collective Academic Supervision”, a model for supervision at the Master of Education in Guidance at Aarhus University in Denmark. The pedagogical rationale behind the model is that students’ participation and learning...

  15. Benchmarking Academic Anatomic Pathologists

    Directory of Open Access Journals (Sweden)

    Barbara S. Ducatman MD

    2016-10-01

    Full Text Available The most common benchmarks for faculty productivity are derived from Medical Group Management Association (MGMA or Vizient-AAMC Faculty Practice Solutions Center ® (FPSC databases. The Association of Pathology Chairs has also collected similar survey data for several years. We examined the Association of Pathology Chairs annual faculty productivity data and compared it with MGMA and FPSC data to understand the value, inherent flaws, and limitations of benchmarking data. We hypothesized that the variability in calculated faculty productivity is due to the type of practice model and clinical effort allocation. Data from the Association of Pathology Chairs survey on 629 surgical pathologists and/or anatomic pathologists from 51 programs were analyzed. From review of service assignments, we were able to assign each pathologist to a specific practice model: general anatomic pathologists/surgical pathologists, 1 or more subspecialties, or a hybrid of the 2 models. There were statistically significant differences among academic ranks and practice types. When we analyzed our data using each organization’s methods, the median results for the anatomic pathologists/surgical pathologists general practice model compared to MGMA and FPSC results for anatomic and/or surgical pathology were quite close. Both MGMA and FPSC data exclude a significant proportion of academic pathologists with clinical duties. We used the more inclusive FPSC definition of clinical “full-time faculty” (0.60 clinical full-time equivalent and above. The correlation between clinical full-time equivalent effort allocation, annual days on service, and annual work relative value unit productivity was poor. This study demonstrates that effort allocations are variable across academic departments of pathology and do not correlate well with either work relative value unit effort or reported days on service. Although the Association of Pathology Chairs–reported median work relative

  16. The Role of Personal Best (PB) and Dichotomous Achievement Goals in Students' Academic Motivation and Engagement: A Longitudinal Investigation

    Science.gov (United States)

    Martin, Andrew J.; Elliot, Andrew J.

    2016-01-01

    This study assessed the role of prior personal best goals in predicting subsequent academic motivation and engagement. A total of 1160 high school students participated in a longitudinal survey study exploring the extent to which personal best and mastery and performance (dichotomous) achievement goals predict students' academic motivation and…

  17. Numerical investigations of buoyancy-driven natural ventilation in a simple atrium building and its effect on the thermal comfort conditions

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2012-01-01

    In the present study use of solar-assisted buoyancy-driven natural ventilation in a simple atrium building is explored numerically with particular emphasis on the thermal comfort conditions in the building. Initially various geometric configurations of the atrium space were considered in order to investigate airflows and temperature distributions in the building using a validated computational fluid dynamics (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modelling approach with the SST-k–ω turbulence model and the Discrete Transfer Radiation Model (DTRM) was used for the investigations. The steady-state governing equations were solved using a commercial CFD solver FLUENT © . From the numerical results obtained, it was noted that an atrium space integrated with a solar chimney would be a relatively better option to be used in an atrium building. In the geometry selected, the performance of the building in response to various changes in design parameters was investigated. The produced airflows and temperature distributions were then used to evaluate indoor thermal comfort conditions in terms of the thermal comfort indices, i.e. the well-known predicted mean vote (PMV) index, its modifications especially for natural ventilation, predicted percent dissatisfied (PPD) index and Percent dissatisfied (PD) factor due to draft. It was found that the thermal conditions in the occupied areas of the building developed as a result of the use of solar-assisted buoyancy-driven ventilation for the particular values of the design parameters selected are mostly in the comfortable zone. Finally, it is demonstrated that the proposed methodology leads to reliable thermal comfort predictions, while the effect of various design variables on the performance of the building is easily recognized. - Highlights: ► Numerical investigations were carried for the use of buoyancy-driven displacement ventilation in a simple atrium building. ► Effect of various atrium

  18. Academic Freedom in Higher Education

    Directory of Open Access Journals (Sweden)

    Tokay GEDİKOĞLU

    2013-12-01

    Full Text Available In this study, the concept ‘academic freedom’ is discussed, its implications and value for the academics, institutions of higher education, and the society are focused, and a few suggestions for the Turkish higher education are made. Academic freedom is defined as the freedom of the academic staff to look for and to find the truth in their scientific field, to publish the findings, and to teach these findings to their students without any external intervention. The concept has gained a further definition with inclusion of research activities into academic freedom as part of the reform attempts started in the German higher education in the 19th century. Therefore, academic freedom is at the very core of the missions of the institutions of higher education; that is, teaching-learning and research. On the point of academic staff and their academic activities of the academic freedom, the subjects such as the aim of the course, choosing the teaching materials and textbooks, the lecturer, and the criteria for the measurement and evaluation of the course take place. And he point of research covers the aim of the study, academicians can’t be imposed the involve in an academic and artistic studies that conflict their values and beliefs; researchers should comply with codes of ethical principles and practices during the process of researching; and research outputs should be reported accurately and honestly without any misleading manipulation. Academic freedom does not provide any exemption from accountability in academic activities of the faculty, nor does it provide any right to act against the well-being of the society, current laws and regulations, and codes of ethical principles and practices.

  19. Exit examinations, peer academic climate, and adolescents' developmental outcomes.

    Science.gov (United States)

    Benner, Aprile D

    2013-02-01

    Implications of high school exit examination performance were examined with a sample of 672 racial/ethnic minority students. Exit examination failure in the 10th grade was negatively linked to subsequent grade point average, school engagement, and school belonging one year later, controlling for outcomes prior to taking the examination. Academically incongruent students-those who failed the exit examination but were in schools where their same-race/ethnicity peers were performing well academically-seemed to be at particular risk for struggling grades and poorer socioemotional well-being (e.g., experiencing greater depressive symptoms and loneliness). Findings contribute to the limited research base on exit examinations and highlight the links between exit examination performance and developmental outcomes beyond the oft-studied academic domain. Copyright © 2012 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  20. Pedagogy and Academic Success in Prelicensure Nursing Education.

    Science.gov (United States)

    Murray, Teri A

    2016-01-01

    The purpose of this article is to provide a brief description of the New Careers in Nursing (NCIN) program; highlight the features of the NCIN Preentry Immersion program designed to help students achieve academic success; introduce two NCIN innovation teaching projects that used active learning strategies to foster student engagement; and conduct an integrative review on the pedagogies used to foster academic success in nursing education. The integrative review revealed that interactive pedagogies fostered student engagement and increased the students' knowledge acquisition, competence, confidence, and satisfaction. Significant variations in the methodological rigor for the studies included in this review were noted in addition to nebulousness between nursing education research and evaluation. The review validated the need for more rigorous research in nursing education to improve the students' academic experience and subsequent success of all nursing students, including those from underrepresented or disadvantaged backgrounds, enrolled in prelicensure nursing education programs. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Peer relationships and academic achievement

    Directory of Open Access Journals (Sweden)

    Krnjajić Stevan B.

    2002-01-01

    Full Text Available After their childhood, when children begin to establish more intensive social contacts outside family, first of all, in school setting, their behavior i.e. their social, intellectual, moral and emotional development is more strongly affected by their peers. Consequently, the quality of peer relationships considerably affects the process of adaptation and academic achievement and their motivational and emotional attitude towards school respectively. Empirical findings showed that there is bi-directional influence between peer relationships and academic achievement. In other words, the quality of peer relationships affects academic achievement, and conversely, academic achievement affects the quality of peer relationships. For example, socially accepted children exhibiting prosocial, cooperative and responsible forms of behavior in school most frequently have high academic achievement. On the other hand, children rejected by their peers often have lower academic achievement and are a risk group tending to delinquency, absenteeism and drop out of school. Those behavioral and interpersonal forms of competence are frequently more reliable predictors of academic achievement than intellectual abilities are. Considering the fact that various patterns of peer interaction differently exert influence on students' academic behavior, the paper analyzed effects of (a social competence, (b social acceptance/rejection, (c child's friendships and (d prosocial behavior on academic achievement.

  2. 38 CFR 36.4324 - Guaranty claims; subsequent accounting.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Guaranty claims; subsequent accounting. 36.4324 Section 36.4324 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... § 36.4324 Guaranty claims; subsequent accounting. (a) Subject to the limitation that the total amounts...

  3. Recurrent miscarriage and antiphospholipid antibodies: prognosis of subsequent pregnancy.

    NARCIS (Netherlands)

    Cohn, D.M.; Goddijn, M.; Middeldorp, S.; Korevaar, J.C.; Dawood, F.; Farquharson, R.G.

    2010-01-01

    Background: Although women with antiphospholipid antibodies (APLAs) are at increased risk of recurrent miscarriage, the outcome of a subsequent pregnancy is not clearly elucidated. Objectives: To assess the pregnancy outcome of a subsequent pregnancy in women with APLAs and compare this outcome with

  4. 29 CFR 1919.30 - Examinations subsequent to unit tests.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Examinations subsequent to unit tests. 1919.30 Section 1919... Treatment; Competent Persons § 1919.30 Examinations subsequent to unit tests. (a) After satisfactory completion of the unit proof load tests required by §§ 1919.27 and 1919.28, the cargo gear and all component...

  5. Subsequence Generation for the Airline Crew Pairing Problem

    DEFF Research Database (Denmark)

    Rasmussen, Matias Sevel; Lusby, Richard Martin; Ryan, David

    of the solutions. The LP solutions from the subsequence generation approach are less fractional, but it comes at the cost of a worse solution quality. The approach in the present paper is novel. To our knowledge generation of subsequences have not been described and tested previously in the literature....

  6. Impact of Selection Bias on Estimation of Subsequent Event Risk

    NARCIS (Netherlands)

    Hu, Yi Juan; Schmidt, Amand F.; Dudbridge, Frank; Holmes, Michael V; Brophy, James M.; Tragante, Vinicius; Li, Ziyi; Liao, Peizhou; Quyyumi, Arshed A.; McCubrey, Raymond O.; Horne, Benjamin D.; Hingorani, Aroon D; Asselbergs, Folkert W; Patel, Riyaz S.; Long, Qi; Åkerblom, Axel; Algra, Ale; Allayee, Hooman; Almgren, Peter; Anderson, Jeffrey L.; Andreassi, Maria G.; Anselmi, Chiara V.; Ardissino, Diego; Arsenault, Benoit J.; Ballantyne, Christie M.; Baranova, Ekaterina V.; Behloui, Hassan; Bergmeijer, Thomas O; Bezzina, Connie R; Bjornsson, Eythor; Body, Simon C.; Boeckx, Bram; Boersma, Eric H.; Boerwinkle, Eric; Bogaty, Peter; Braund, Peter S; Breitling, Lutz P.; Brenner, Hermann; Briguori, Carlo; Brugts, Jasper J.; Burkhardt, Ralph; Cameron, Vicky A.; Carlquist, John F.; Carpeggiani, Clara; Carruthers, Kathryn F.; Casu, Gavino; Condorelli, Gianluigi; Cresci, Sharon; Danchin, Nicolas; de Faire, Ulf; Deanfield, John; Delgado, Graciela; Deloukas, Panos; Direk, Kenan; Doughty, Robert N.; Drexel, Heinz; Duarte, Nubia E.; Dubé, Marie Pierre; Dufresne, Line; Engert, James C; Eriksson, Niclas; Fitzpatrick, Natalie; Foco, Luisa; Ford, Ian; Fox, Keith A; Gigante, Bruna; Gijsberts, Crystel M.; Girelli, Domenico; Gong, Yan; Gudbjartsson, Daniel F.; Hagström, Emil; Hartiala, Jaana; Hazen, Stanley L.; Held, Claes; Helgadottir, Anna; Hemingway, Harry; Heydarpour, Mahyar; Hoefer, Imo E.; Hovingh, G. Kees; Hubacek, Jaroslav A; James, Stefan; Johnson, Julie A; Jukema, J Wouter; Kaczor, Marcin P.; Kaminski, Karol A.; Kettner, Jiri; Kiliszek, Marek; Kleber, Marcus; Klungel, Olaf H.; Kofink, Daniel; Kohonen, Mika; Kotti, Salma; Kuukasjärvi, Pekka; Lagerqvist, Bo; Lambrechts, Diether; Lang, Chim C; Laurikka, Jari O.; Leander, Karin; Lee, Vei Vei; Lehtimäki, Terho; Leiherer, Andreas; Lenzini, Petra A.; Levin, Daniel; Lindholm, Daniel; Lokki, Marja-Liisa; Lotufo, Paulo A; Lyytikäinen, Leo-Pekka; Mahmoodi, B. Khan; Maitland-Van Der Zee, Anke H.; Martinelli, Nicola; März, Winfried; Marziliano, Nicola; McPherson, Ruth; Melander, Olle; Mons, Ute; Muehlschlegel, Jochen D.; Muhlestein, Joseph B.; Nelson, Cristopher P.; Cheh, Chris Newton; Olivieri, Oliviero; Opolski, Grzegorz; Palmer, Colin Na; Pare, Guillaume; Pasterkamp, Gerard; Pepine, Carl J; Pepinski, Witold; Pereira, Alexandre C.; Pilbrow, Anna P.; Pilote, Louise; Pitha, Jan; Ploski, Rafal; Richards, A. Mark; Saely, Christoph H.; Samani, Nilesh J; Samman-Tahhan, Ayman; Sanak, Marek; Sandesara, Pratik B.; Sattar, Naveed; Scholz, Markus; Siegbahn, Agneta; Simon, Tabassome; Sinisalo, Juha; Smith, J. Gustav; Spertus, John A.; Stefansson, Kari; Stewart, Alexandre F R; Stott, David J.; Szczeklik, Wojciech; Szpakowicz, Anna; Tanck, Michael W.T.; Tang, Wilson H.; Tardif, Jean-Claude; Ten Berg, Jur M.; Teren, Andrej; Thanassoulis, George; Thiery, Joachim; Thorgeirsson, Gudmundur; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Timmis, Adam; Trompet, Stella; Van de Werf, Frans; van der Graaf, Yolanda; Van Der Haarst, Pim; van der Laan, Sander W; Vilmundarson, Ragnar O.; Virani, Salim S.; Visseren, Frank L J; Vlachopoulou, Efthymia; Wallentin, Lars; Waltenberger, Johannes; Wauters, Els; Wilde, Arthur A M

    2017-01-01

    Background - Studies of recurrent or subsequent disease events may be susceptible to bias caused by selection of subjects who both experience and survive the primary indexing event. Currently, the magnitude of any selection bias, particularly for subsequent time-to-event analysis in genetic

  7. Morbidity and risk of subsequent diagnosis of HIV

    DEFF Research Database (Denmark)

    Søgaard, Ole S; Lohse, Nicolai; Østergaard, Lars Jørgen

    2012-01-01

    Early identification of persons with undiagnosed HIV infection is an important health care issue. We examined associations between diseases diagnosed in hospitals and risk of subsequent HIV diagnosis.......Early identification of persons with undiagnosed HIV infection is an important health care issue. We examined associations between diseases diagnosed in hospitals and risk of subsequent HIV diagnosis....

  8. SUBSEQUENTLY AQCUIRED ASSETS AS FIDUCIARY SECURITY ON BANK LOANS

    Directory of Open Access Journals (Sweden)

    Trisadini Prasastinah Usanti

    2016-05-01

    Full Text Available Collateral in terms of subsequently acquired assets namely subsequently acquired credit might be charged with fiduciary security. This collateral is not considered ideal regarding the high risk a bank must take. To minimize the risks, the bank analyzes the credit thoroughly, impose fiduciary security officials perfectly and performs monitoring of credits regularly to avoid misconduct committed by the debtor. If a default occurs, the bank will take over the assets. Nevertheless, the problems of execution on the subsequently acquired credits might arise due to debtor’s default and bad debts to the third party. Consequently, subsequently acquired assets as collateral provides as additional collateral. Keywords: bank, subsequently acquired objects, fiduciary, security, loans.

  9. Some Exact Solutions of Boundary Layer Flows along a Vertical Plate with Buoyancy Forces Combined with Lorentz Forces under Uniform Suction

    Directory of Open Access Journals (Sweden)

    Asterios Pantokratoras

    2008-01-01

    Full Text Available Exact analytical solutions of boundary layer flows along a vertical porous plate with uniform suction are derived and presented in this paper. The solutions concern the Blasius, Sakiadis, and Blasius-Sakiadis flows with buoyancy forces combined with either MHD Lorentz or EMHD Lorentz forces. In addition, some exact solutions are presented specifically for water in the temperature range of 0∘C≤≤8∘C, where water density is nearly parabolic. Except for their use as benchmarking means for testing the numerical solution of the Navier-Stokes equations, the presented exact solutions with EMHD forces have use in flow separation control in aeronautics and hydronautics, whereas the MHD results have applications in process metallurgy and fusion technology. These analytical solutions are valid for flows with strong suction.

  10. Origins and Early History of Underwater Neutral Buoyancy Simulation of Weightlessness for EVA Procedures Development and Training. Part 2; Winnowing and Regrowth

    Science.gov (United States)

    Charles, John B.

    2013-01-01

    The technique of neutral buoyancy during water immersion was applied to a variety of questions pertaining to human performance factors in the early years of the space age. It was independently initiated by numerous aerospace contractors at nearly the same time, but specific applications depended on the problems that the developers were trying to solve. Those problems dealt primarily with human restraint and maneuverability and were often generic across extravehicular activity (EVA) and intravehicular activity (IVA) worksites. The same groups often also considered fractional gravity as well as weightless settings and experimented with ballasting to achieve lunar and Mars-equivalent loads as part of their on-going research and development. Dr. John Charles reviewed the association of those tasks with contemporary perceptions of the direction of NASA's future space exploration activities and with Air Force assessments of the military value of man in space.

  11. Performance samples on academic tasks : improving prediction of academic performance

    NARCIS (Netherlands)

    Tanilon, Jenny

    2011-01-01

    This thesis is about the development and validation of a performance-based test, labeled as Performance Samples on academic tasks in Education and Child Studies (PSEd). PSEd is designed to identify students who are most able to perform the academic tasks involved in an Education and Child Studies

  12. The "Second Academic Revolution": Interpretations of Academic Entrepreneurship

    Science.gov (United States)

    Zheng, Peijun

    2010-01-01

    The number and scope of faculty and institutions involved in academic entrepreneurship continues to expand, and this has significant implications for universities, involving potentially wonderful opportunities but also dire risks. This paper looks beyond academic capitalism, a theory that currently dominates the study of higher education, by…

  13. Academic Entrepreneurship and Traditional Academic Duties: Synergy or Rivalry?

    Science.gov (United States)

    De Silva, Muthu

    2016-01-01

    This study investigates the influence of academic entrepreneurship on traditional academic duties carried out in a resource-constrained environment, particularly focusing on whether there is synergy or rivalry between these two activities. Using qualitative evidence, we discover that there are funding, resource, knowledge and skill and networking…

  14. Are You an Academic Stock or an Academic Bond?

    Science.gov (United States)

    Berns, Gregory

    2008-01-01

    Academic scholarship is a business, and just like any other business, it is driven largely by the incentive for profit. Those profits may or may not be financial in nature, but the potential for reward, whether it is measured in terms of a promotion or of intellectual property, underlies whatever people do in higher education. Academics don't…

  15. Making Sense of Academic Life: Academics, Universities and Change.

    Science.gov (United States)

    Taylor, Peter G.

    Universities and academics today are facing challenges that require more active and self-interested management. The book argues that higher education in the future will not become any more ordered, but will actually become more complex, more fractured and less bounded, and that academics will have to respond with new ways of thinking. The book…

  16. Travelling Academics: The Lived Experience of Academics Moving across Countries

    Science.gov (United States)

    Uusimaki, Liisa; Garvis, Susanne

    2017-01-01

    The article reports on a study that explored the personal narratives of two female travelling academics at a Swedish University who had moved from Australia. To complement previous accounts of difficult migration and enculturation within the research literature, this article focuses mainly on the successful experiences of the academics and how…

  17. Students' Motivation to Access Academic Advising Services

    Science.gov (United States)

    Henning, Marcus A.

    2009-01-01

    The interrelationships between motivation for choosing a program of study, intention to access academic advisors, academic difficulty, and actual appointments with academic advisors were based on student self-reports of motivation and intentions. In addition, academic achievement measures and data on student access to academic advisors were…

  18. Diet Quality and Academic Performance

    Science.gov (United States)

    Florence, Michelle D.; Asbridge, Mark; Veugelers, Paul J.

    2008-01-01

    Background: Although the effects of nutrition on health and school performance are often cited, few research studies have examined the effect of diet quality on the academic performance of children. This study examines the association between overall diet quality and academic performance. Methods: In 2003, 5200 grade 5 students in Nova Scotia,…

  19. 'Military Thinkers and Academic Thinkers'

    DEFF Research Database (Denmark)

    Haugegaard, Rikke

    Culture analysis seems to create friction when we try to introduce academic concepts relating to culture to military planners. This friction might be related to the fact that officers and academics do their thinking in different 'spaces'. This paper argues the interface or overlapping space between...

  20. Undergraduate students' perceived academic environmental ...

    African Journals Online (AJOL)

    This study examined the relationship between undergraduates' perception of the academic environment, their attitude to academic work and achievement. A total of 348 undergraduates who formed the sample were drawn from five departments in three universities in Nigeria. The study revealed that four dimensions of the ...

  1. Physical Activity and Academic Achievement

    Centers for Disease Control (CDC) Podcasts

    2014-12-09

    This podcast highlights the evidence that supports the link between physical activity and improved academic achievement. It also identifies a few actions to support a comprehensive school physical activity program to improve academic achievement.  Created: 12/9/2014 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 12/9/2014.

  2. Machine Translation for Academic Purposes

    Science.gov (United States)

    Lin, Grace Hui-chin; Chien, Paul Shih Chieh

    2009-01-01

    Due to the globalization trend and knowledge boost in the second millennium, multi-lingual translation has become a noteworthy issue. For the purposes of learning knowledge in academic fields, Machine Translation (MT) should be noticed not only academically but also practically. MT should be informed to the translating learners because it is a…

  3. The Academic Profession in Transition.

    Science.gov (United States)

    Bess, James L.

    1977-01-01

    (NOTE: The Fall 1977, Winter 1978, and Spring 1978 issues of this journal were published under the title "Higher Education Review"; thereafter, the name was changed to "Review of Higher Education.") To meet changing demands of society for academic services in academe, restructuring of the institutions is proposed. Departmentalization, cluster…

  4. Transnational Academic Mobility and Gender

    Science.gov (United States)

    Jons, Heike

    2011-01-01

    This paper examines to what extent the participation of researchers in transnational academic mobility, their experiences and perceived outcomes vary by gender. Based on longitudinal statistics, original survey data and semi-structured interviews with former visiting researchers in Germany, the paper shows that the academic world of female…

  5. Healthy Eating and Academic Achievement

    Centers for Disease Control (CDC) Podcasts

    2014-12-09

    This podcast highlights the evidence that supports the link between healthy eating and improved academic achievement. It also identifies a few actions to support a healthy school nutrition environment to improve academic achievement.  Created: 12/9/2014 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 12/9/2014.

  6. Academic journalese for the Internet

    DEFF Research Database (Denmark)

    Yli-Jokipii, Hilkka; Jørgensen, Poul Erik Flyvholm

    2004-01-01

    The purpose of the present study is to investigate, within the textual framework of academic journalese, what happens to Danish and Finnish writers' English texts when edited by native English-speaking editors for publication on the World Wide Web. We use the term academic journalese to describe...

  7. Entrepreneurship Education and Academic Performance

    Science.gov (United States)

    Johansen, Vegard

    2014-01-01

    The significant increase of entrepreneurship education (EE) is a trend in Europe. Entrepreneurship education is supposed to promote general and specific entrepreneurial abilities and improve academic performance. This paper evaluates whether EE influences academic performance, measured by Grade Point Average. The main indicator used for EE is the…

  8. Constructivism, Dewey, and Academic Advising

    Science.gov (United States)

    Xyst, Kurt

    2016-01-01

    Many published scholars argue for constructivism as a basis for academic advising theory. However, few have discussed the commensurate ontological assumptions of constructivist thinking. Potential problems with the metaphysical view of the student in contemporary academic advising may be attributable to constructivism. John Dewey's critique of…

  9. Academic Education Chain Operation Model

    OpenAIRE

    Ruskov, Petko; Ruskov, Andrey

    2007-01-01

    This paper presents an approach for modelling the educational processes as a value added chain. It is an attempt to use a business approach to interpret and compile existing business and educational processes towards reference models and suggest an Academic Education Chain Operation Model. The model can be used to develop an Academic Chain Operation Reference Model.

  10. Comics, Copyright and Academic Publishing

    Directory of Open Access Journals (Sweden)

    Ronan Deazley

    2014-05-01

    Full Text Available This article considers the extent to which UK-based academics can rely upon the copyright regime to reproduce extracts and excerpts from published comics and graphic novels without having to ask the copyright owner of those works for permission. In doing so, it invites readers to engage with a broader debate about the nature, demands and process of academic publishing.

  11. Academic underachievement: A neurodevelopmental perspective

    Directory of Open Access Journals (Sweden)

    K. Shapiro Bruce, MD

    2011-03-01

    Full Text Available Academic underachievement is a common presenting symptom and has many different causes. The disorders that describe academic underachievement are based on the child’s function in cognitive, academic, or behavioral domains. The disorders that are associated with academic underachievement are final common pathways that have different etiologies and mechanisms. Multiple disorders are the rule because brain dysfunction in childhood usually affects multiple functions. Consequently, management programs must be individualized, comprehensive and address issues related to the child, school, and family. Treatment plans include parent training, academic accommodations, techniques to maintain self-esteem, and psychopharmacologic approaches. Ongoing monitoring of the management programs is necessary to detect important comorbidities that may emerge, to modify the program to meet the changing academic and social demands that occur as the child ages, and to provide current information. The outcome for children with academic underachievement is most dependent on the underlying disorder. Health providers have multiple roles to play in the prevention, detection, diagnosis and management of children with academic underachievement.

  12. Monitoring Students' Academic & Disciplinary Progression.

    Science.gov (United States)

    McDonald, Fred; Kellogg, Larry J.

    This document outlines the objectives and procedures of a program at a New Mexico school district whose purpose is to enable school personnel to systematically monitor students' academic and disciplinary progression. The objectives of the program are to diagnose academic or disciplinary problems and prescribe remedies, to establish an oncampus…

  13. Nursing Faculty and Academic Integrity

    Science.gov (United States)

    Wilson, Cecilia E.

    2013-01-01

    Insufficient information exists regarding the process influencing faculty decisions, specifically in the area of maintaining academic integrity in an online environment. The purpose of the study was to explore the experiences and decision-making process of nursing faculty related to maintaining academic integrity in an online environment. The…

  14. Financing Academic Departments of Psychiatry

    Science.gov (United States)

    Liptzin, Benjamin; Meyer, Roger E.

    2011-01-01

    Objective: The authors describe the many financial challenges facing academic departments of psychiatry and the resulting opportunities that may arise. Method: The authors review the history of financial challenges, the current economic situation, and what may lie ahead for academic departments of psychiatry. Results: The current environment has…

  15. Self-initiated expatriate academics

    DEFF Research Database (Denmark)

    Selmer, Jan; Lauring, Jakob

    2013-01-01

    In this chapter we examine self-initiated expatriate academics. Universities are to an increasing extent looking for talent beyond national boundaries. Accordingly, self-initiated expatriate academics represent a fast growing group of highly educated professionals who gain employment abroad...

  16. Academic entitlement in pharmacy education.

    Science.gov (United States)

    Cain, Jeff; Romanelli, Frank; Smith, Kelly M

    2012-12-12

    The constructs of academic entitlement and student consumerism refer to students' attitudes toward education as a commodity and the underlying belief that as consumers, they should be catered to and given the opportunity to participate in the education process according to their preferences. Most discussions regarding these attitudes are anecdotal, but the pervasiveness of these accounts and the troubling effects that ensue warrant attention. Grade inflation, student incivility, altered classroom practices, and decreased faculty morale are all potential aftereffects of teaching students who hold academic entitlement beliefs. Numerous factors are posited as attributing to academic entitlement including personal issues, societal pressures, and broad academic practices. This paper discusses these factors and offers faculty members and administrators recommendations regarding practices that may curb or alleviate issues associated with academically entitled students.

  17. Sleep and Academic Performance in Undergraduates: A Multi-measure, Multi-predictor Approach

    OpenAIRE

    Gomes, Ana Allen; Tavares, José; de Azevedo, Maria Helena P.

    2011-01-01

    The present study examined the associations of sleep patterns with multiple measures of academic achievement of undergraduate university students and tested whether sleep variables emerged as significant predictors of subsequent academic performance when other potential predictors, such as class attendance, time devoted to study, and substance use are considered. A sample of 1654 (55% female) full-time undergraduates 17 to 25 yrs of age responded to a self-response questionnaire on sleep, aca...

  18. An intercalated BSc degree is associated with higher marks in subsequent medical school examinations

    Directory of Open Access Journals (Sweden)

    Sinclair Hazel

    2009-05-01

    Full Text Available Abstract Background To compare medical students on a modern MBChB programme who did an optional intercalated degree with their peers who did not intercalate; in particular, to monitor performance in subsequent undergraduate degree exams. Methods This was a retrospective, observational study of anonymised databases of medical student assessment outcomes. Data were accessed for graduates, University of Aberdeen Medical School, Scotland, UK, from the years 2003 to 2007 (n = 861. The main outcome measure was marks for summative degree assessments taken after intercalating. Results Of 861 medical students, 154 (17.9% students did an intercalated degree. After adjustment for cohort, maturity, gender and baseline (3rd year performance in matching exam type, having done an IC degree was significantly associated with attaining high (18–20 common assessment scale (CAS marks in three of the six degree assessments occurring after the IC students rejoined the course: the 4th year written exam (p th year OSCE (p = 0.001 and the 5th year Elective project (p = 0.010. Conclusion Intercalating was associated with improved performance in Years 4 and 5 of the MBChB. This improved performance will further contribute to higher academic ranking for Foundation Year posts. Long-term follow-up is required to identify if doing an optional intercalated degree as part of a modern medical degree is associated with following a career in academic medicine.

  19. Is past academic productivity predictive of radiology resident academic productivity?

    Science.gov (United States)

    Patterson, Stephanie K; Fitzgerald, James T; Boyse, Tedric D; Cohan, Richard H

    2002-02-01

    The authors performed this study to determine whether academic productivity in college and medical school is predictive of the number of publications produced during radiology residency. The authors reviewed the records of 73 radiology residents who completed their residency from 1990 to 2000. Academic productivity during college, medical school, and radiology residency, other postgraduate degrees, and past careers other than radiology were tabulated. The personal essay attached to the residency application was reviewed for any stated academic interest. Residents were classified as being either previously productive or previously unproductive. Publication rates during residency and immediately after residency were compared for the two groups. For the productive residents, a correlation analysis was used to examine the relationship between past frequency of publication and type of previous activity. Least-squares regression analysis was used to investigate the relationship between preresidency academic productivity, advanced degrees, stated interest in academics, and other careers and radiology residency publications. There was no statistically significant difference in the number of articles published by those residents who were active and those who were not active before residency (P = .21). Only authorship of papers as an undergraduate was weakly predictive of residency publication. These selected measures of academic productivity as an undergraduate and during medical school are not helpful for predicting publication during residency. There was no difference in publication potential between those residents who were academically productive in the past and those who were not.

  20. Associations between mental disorders and subsequent onset of hypertension

    NARCIS (Netherlands)

    Stein, Dan J.; Aguilar-Gaxiola, Sergio; Alonso, Jordi; Bruffaerts, Ronny; de Jonge, Peter; Liu, Zharoui; Caldas-de-Almeida, Jose Miguel; O'Neill, Siobhan; Viana, Maria Carmen; Al-Hamzawi, Ali Obaid; Angermeyer, Mattias C.; Benjet, Corina; de Graaf, Ron; Ferry, Finola; Kovess-Masfety, Viviane; Levinson, Daphna; de Girolamo, Giovanni; Florescu, Silvia; Hu, Chiyi; Kawakami, Norito; Haro, Josep Maria; Piazza, Marina; Posada-Villa, Jose; Wojtyniak, Bogdan J.; Xavier, Miguel; Lim, Carmen C. W.; Kessler, Ronald C.; Scott, Kate M.

    2014-01-01

    Background: Previous work has suggested significant associations between various psychological symptoms (e. g., depression, anxiety, anger, alcohol abuse) and hypertension. However, the presence and extent of associations between common mental disorders and subsequent adult onset of hypertension

  1. On How Editors of Academic Journals at Institutions of Higher Learning Should Resist Academic Corruption

    Science.gov (United States)

    Jing, Xiao

    2007-01-01

    Academic corruption is a hot issue in today's society. "Academic corruption" means that certain individuals in academic circles, driven by the desire for personal gain, resort to various kinds of nonnormative and unethical behavior in academic research activities. These include: academic self-piracy, academic piracy, copying and…

  2. Measuring Academic Motivation of Matriculating College Freshmen.

    Science.gov (United States)

    Baker, Robert W.; Siryk, Bohdan

    1984-01-01

    Administered the Academic Motivation Scale to three successive classes of college freshmen (N=944). Results indicated the Academic Motivation Scale's reliability was more than adequate for research use and significantly related to validity criteria reflecting motivation for academic work. (JAC)

  3. The influence of children's pain memories on subsequent pain experience.

    Science.gov (United States)

    Noel, Melanie; Chambers, Christine T; McGrath, Patrick J; Klein, Raymond M; Stewart, Sherry H

    2012-08-01

    Healthy children are often required to repeatedly undergo painful medical procedures (eg, immunizations). Although memory is often implicated in children's reactions to future pain, there is a dearth of research directly examining the relationship between the 2. The current study investigated the influence of children's memories for a novel pain stimulus on their subsequent pain experience. One hundred ten healthy children (60 boys) between the ages of 8 and 12 years completed a laboratory pain task and provided pain ratings. Two weeks later, children provided pain ratings based on their memories as well as their expectancies about future pain. One month following the initial laboratory visit, children again completed the pain task and provided pain ratings. Results showed that children's memory of pain intensity was a better predictor of subsequent pain reporting than their actual initial reporting of pain intensity, and mediated the relationship between initial and subsequent pain reporting. Children who had negatively estimated pain memories developed expectations of greater pain prior to a subsequent pain experience and showed greater increases in pain ratings over time than children who had accurate or positively estimated pain memories. These findings highlight the influence of pain memories on healthy children's expectations of future pain and subsequent pain experiences and extend predictive models of subsequent pain reporting. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  4. University Students' Satisfaction with their Academic Studies: Personality and Motivation Matter.

    Science.gov (United States)

    Wach, F-Sophie; Karbach, Julia; Ruffing, Stephanie; Brünken, Roland; Spinath, Frank M

    2016-01-01

    Although there is consensus about the importance of students' satisfaction with their academic studies as one facet of academic success, little is known about the determinants of this significant outcome variable. Past research rarely investigated the predictive power of multiple predictors simultaneously. Hence, we examined how demographic variables, personality, cognitive and achievement-related variables (intelligence, academic achievement), as well as various motivational constructs were associated with three different dimensions of satisfaction (satisfaction with study content, satisfaction with the conditions of the academic program, satisfaction with the ability to cope with academic stress) assessed approximately 2 years apart. Analyzing data of a sample of university students (N = 620; M age = 20.77; SD age = 3.22) using structural equation modeling, our results underline the significance of personality and motivational variables: Neuroticism predicted satisfaction with academic studies, but its relevance varied between outcome dimensions. Regarding the predictive validity of motivational variables, the initial motivation for enrolling in a particular major was correlated with two dimensions of subsequent satisfaction with academic studies. In contrast, the predictive value of cognitive and achievement-related variables was relatively low, with academic achievement only related to satisfaction with the conditions of the academic program after controlling for the prior satisfaction level.

  5. Mental health predicts better academic outcomes: a longitudinal study of elementary school students in Chile.

    Science.gov (United States)

    Murphy, J Michael; Guzmán, Javier; McCarthy, Alyssa E; Squicciarini, Ana María; George, Myriam; Canenguez, Katia M; Dunn, Erin C; Baer, Lee; Simonsohn, Ariela; Smoller, Jordan W; Jellinek, Michael S

    2015-04-01

    The world's largest school-based mental health program, Habilidades para la Vida [Skills for Life (SFL)], has been operating on a national scale in Chile for 15 years. SFL's activities include using standardized measures to screen elementary school students and providing preventive workshops to students at risk for mental health problems. This paper used SFL's data on 37,397 students who were in first grade in 2009 and third grade in 2011 to ascertain whether first grade mental health predicted subsequent academic achievement and whether remission of mental health problems predicted improved academic outcomes. Results showed that mental health was a significant predictor of future academic performance and that, overall, students whose mental health improved between first and third grade made better academic progress than students whose mental health did not improve or worsened. Our findings suggest that school-based mental health programs like SFL may help improve students' academic outcomes.

  6. Women in academic general surgery.

    Science.gov (United States)

    Schroen, Anneke T; Brownstein, Michelle R; Sheldon, George F

    2004-04-01

    To portray the professional experiences of men and women in academic general surgery with specific attention to factors associated with differing academic productivity and with leaving academia. A 131-question survey was mailed to all female (1,076) and a random 2:1 sample of male (2,152) members of the American College of Surgeons in three mailings between September 1998 and March 1999. Detailed questions regarding academic rank, career aspirations, publication rate, grant funding, workload, harassment, income, marriage and parenthood were asked. A five-point Likert scale measured influences on career satisfaction. Responses from strictly academic and tenure-track surgeons were analyzed and interpreted by gender, age, and rank. Overall, 317 surgeons in academic practice (168 men, 149 women) responded, of which 150 were in tenure-track positions (86 men, 64 women). Men and women differed in academic rank, tenure status, career aspirations, and income. Women surgeons had published a median of ten articles compared with 25 articles for men (p career satisfaction was high, but women reported feeling career advancement opportunities were not equally available to them as to their male colleagues and feeling isolation from surgical peers. Ten percent to 20% of surgeons considered leaving academia, with women assistant professors (29%) contemplating this most commonly. Addressing the differences between men and women academic general surgeons is critical in fostering career development and in recruiting competitive candidates of both sexes to general surgery.

  7. The Effect of Academic Advising on Academic Performance of ...

    African Journals Online (AJOL)

    User

    percentage (11%) of students seeking academic advising and students' needs .... Students at different years of study experience different and unique problems ..... sociocultural and clinical literature with particular reference to depression.

  8. A Test of the Reciprocal-Effects Model of Academic Achievement and Academic Self-Concept in Regular Classes and Special Classes for the Gifted

    Science.gov (United States)

    Preckel, Franzis; Schmidt, Isabelle; Stumpf, Eva; Motschenbacher, Monika; Vogl, Katharina; Schneider, Wolfgang

    2017-01-01

    According to the reciprocal-effects model (REM), prior academic self-concept (ASC) has a positive effect on subsequent achievement beyond what can be explained in terms of prior achievement and vice versa. The present study investigated the REM for students studying in special classes for the gifted compared to students studying in regular…

  9. The academic library network

    Directory of Open Access Journals (Sweden)

    Jacek Wojciechowski

    2012-01-01

    Full Text Available The efficiency of libraries, academic libraries in particular, necessitates organizational changes facilitating or even imposing co-operation. Any structure of any university has to have an integrated network of libraries, with an appropriate division of work, and one that is consolidated as much as it is possible into medium-size or large libraries. Within thus created network, a chance arises to centralize the main library processes based on appropriate procedures in the main library, highly specialized, more effective and therefore cheaper in operation, including a co-ordination of all more important endeavours and tasks. Hierarchically subordinated libraries can be thus more focused on performing their routine service, more and more frequently providing for the whole of the university, and being able to adjust to changeable requirements and demands of patrons and of new tasks resulting from the new model of the university operation. Another necessary change seems to be a universal implementation of an ov rall programme framework that would include all services in the university’s library networks.

  10. The survey of academic libraries

    CERN Document Server

    2014-01-01

    The Survey of Academic Libraries, 2014-15 Edition looks closely at key benchmarks for academic libraries in areas such as spending for books and e-books, deployment and pay rates for student workers, use of tablet computers, cloud computing and other new technologies, database licensing practices, and much more. The study includes detailed data on overall budgets, capital budgets, salaries and materials spending, and much more of interest to academic librarians and their suppliers. Data in this 200+ page report is broken out by size and type of library for easy benchmarking.

  11. New threats to academic freedom.

    Science.gov (United States)

    Minerva, Francesca

    2014-05-01

    Using a specific case as an example, the article argues that the Internet allows dissemination of academic ideas to the general public in ways that can sometimes pose a threat to academic freedom. Since academic freedom is a fundamental element of academia and since it benefits society at large, it is important to safeguard it. Among measures that can be taken in order to achieve this goal, the publication of anonymous research seems to be a good option. © 2013 John Wiley & Sons Ltd.

  12. Academic procrastination: An exploratory study

    Directory of Open Access Journals (Sweden)

    Rita Karina Nobre Sampaio

    2011-10-01

    Full Text Available Academic procrastination has been understood as a dynamic phenomenon, which involves personal, behavioral and environmental issues and is characterized by the postponement of non-strategic actions. This behavior may affect the academic performance of the students. The present study aimed to describe the procrastination among university students, and identify activities that are more or less delayed and feelings reported to be procrastinating.The results indicate the frequency of procrastination among university students, as well as a list of academic tasks and unpleasant feelings postponed to procrastinate.

  13. Computer Anxiety, Academic Stress, and Academic Procrastination on College Students

    OpenAIRE

    Wahyu Rahardjo; Juneman Juneman; Yeni Setiani

    2013-01-01

    Academic procrastination is fairly and commonly found among college students. The lack of understanding in making the best use of computer technology may lead to anxiety in terms of operating computer hence cause postponement in completing course assignments related to computer operation. On the other hand, failure in achieving certain academic targets as expected by parents and/or the students themselves also makes students less focused and leads to tendency of postponing many completions of...

  14. Associations between mental disorders and subsequent onset of hypertension

    Science.gov (United States)

    Stein, Dan J.; Aguilar-Gaxiola, Sergio; Alonso, Jordi; Bruffaerts, Ronny; de Jonge, Peter; Liu, Zharoui; Caldas-de-Almeida, Jose Miguel; O’Neill, Siobhan; Viana, Maria Carmen; Al-Hamzawi, Ali Obaid; Angermeyer, Mattias C.; Benjet, Corina; de Graaf, Ron; Ferry, Finola; Kovess-Masfety, Viviane; Levinson, Daphna; de Girolamo, Giovanni; Florescu, Silvia; Hu, Chiyi; Kawakami, Norito; Haro, Josep Maria; Piazza, Marina; Wojtyniak, Bogdan J; Xavier, Miguel; Lim, Carmen C.W.; Kessler, Ronald C.; Scott, Kate

    2013-01-01

    Background Previous work has suggested significant associations between various psychological symptoms (e.g. depression, anxiety, anger, alcohol abuse) and hypertension. However, the presence and extent of associations between common mental disorders and subsequent adult onset of hypertension remains unclear. Further, there is little data available on how such associations vary by gender or over life course. Methods Data from the World Mental Health Surveys (comprising 19 countries, and 52,095 adults) were used. Survival analyses estimated associations between first onset of common mental disorders and subsequent onset of hypertension, with and without psychiatric comorbidity adjustment. Variations in the strength of associations by gender and by life course stage of onset of both the mental disorder and hypertension were investigated. Results After psychiatric comorbidity adjustment, depression, panic disorder, social phobia, specific phobia, binge eating disorder, bulimia nervosa, alcohol abuse, and drug abuse were significantly associated with subsequent diagnosis of hypertension (with ORs ranging from 1.1 to 1.6). Number of lifetime mental disorders was associated with subsequent hypertension in a dose-response fashion. For social phobia and alcohol abuse, associations with hypertension were stronger for males than females. For panic disorder, the association with hypertension was particularly apparent in earlier onset hypertension. Conclusions Depression, anxiety, impulsive eating disorders, and substance use disorders disorders were significantly associated with the subsequent diagnosis of hypertension. These data underscore the importance of early detection of mental disorders, and of physical health monitoring in people with these conditions.. PMID:24342112

  15. ACADEMIC TRAINING LECTURES-QUESTIONNAIRE

    CERN Multimedia

    Françoise Benz

    2004-01-01

    ACADEMIC TRAINING Françoise Benz tel. 73127 academic.training@cern.ch SUGGEST AND WIN! Its time to plan the 2004-2005 lecture series. From today until March 19 you have the chance to give your contribution to planning for next year's Academic Training Lecture Series. At the web site: http://cern.ch/Academic.Training/questionnaire you will find questionnaires proposing topics in high energy physics, applied physics and science and society. Answering the questionnaire will help ensure that the selected topics are as close as possible to your interests. In particular requests and comments from students will be much appreciated. To encourage your contribution, the AT Committee will reward one lucky winner with a small prize, a 50 CHF coupon for a book purchase at the CERN bookshop.

  16. Personality, academic majors and performance

    DEFF Research Database (Denmark)

    Vedel, Anna; Thomsen, Dorthe Kirkegaard; Larsen, Lars

    2015-01-01

    Personality–performance research typically uses samples of psychology students without questioning their representativeness. The present article reports two studies challenging this practice. Study 1: group differences in the Big Five personality traits were explored between students (N = 1067......) in different academic majors (medicine, psychology, law, economics, political science, science, and arts/humanities), who were tested immediately after university enrolment. Study 2: six and a half years later the students’ academic records were obtained, and predictive validity of the Big Five personality...... traits and their subordinate facets was examined in the various academic majors in relation to Grade Point Average (GPA). Significant group differences in all Big Five personality traits were found between students in different academic majors. Also, variability in predictive validity of the Big Five...

  17. Academic Locus of Control, Tendencies Towards Academic Dishonesty and Test Anxiety Levels as the Predictors of Academic Self-Efficacy

    Science.gov (United States)

    Yesilyurt, Etem

    2014-01-01

    Many studies have focused on finding the level of effect that academic locus of control, tendencies towards academic dishonesty, and test anxiety levels have had on academic self-efficacy, and providing a separate explanation ratio for each. The relationship among the effects of the academic locus of control, tendencies towards academic…

  18. The Role of Academic Self-Efficacy as a Mediator Variable between Perceived Academic Climate and Academic Performance

    Science.gov (United States)

    Abd-Elmotaleb, Moustafa; Saha, Sudhir K.

    2013-01-01

    This study examines the mediating influence of academic self-efficacy on the link between perceived academic climate and academic performance among university students. The participants in the study consist of 272 undergraduate students at the University of Assiut, Assiut, Egypt. A scale to measure perceived academic climate, was developed. To…

  19. Women's decision making and experience of subsequent pregnancy following stillbirth.

    Science.gov (United States)

    Lee, Louise; McKenzie-McHarg, Kirstie; Horsch, Antje

    2013-01-01

    This study sought to increase understanding of women's thoughts and feelings about decision making and the experience of subsequent pregnancy following stillbirth (intrauterine death after 24 weeks' gestation). Eleven women were interviewed, 8 of whom were pregnant at the time of the interview. Modified grounded theory was used to guide the research methodology and to analyze the data. A model was developed to illustrate women's experiences of decision making in relation to subsequent pregnancy and of subsequent pregnancy itself. The results of the current study have significant implications for women who have experienced stillbirth and the health professionals who work with them. Based on the model, women may find it helpful to discuss their beliefs in relation to healing and health professionals to provide support with this in mind. Women and their partners may also benefit from explanations and support about the potentially conflicting emotions they may experience during this time. © 2013 by the American College of Nurse-Midwives.

  20. Faster Algorithms for Computing Longest Common Increasing Subsequences

    DEFF Research Database (Denmark)

    Kutz, Martin; Brodal, Gerth Stølting; Kaligosi, Kanela

    2011-01-01

    of the alphabet, and Sort is the time to sort each input sequence. For k⩾3 length-n sequences we present an algorithm which improves the previous best bound by more than a factor k for many inputs. In both cases, our algorithms are conceptually quite simple but rely on existing sophisticated data structures......We present algorithms for finding a longest common increasing subsequence of two or more input sequences. For two sequences of lengths n and m, where m⩾n, we present an algorithm with an output-dependent expected running time of and O(m) space, where ℓ is the length of an LCIS, σ is the size....... Finally, we introduce the problem of longest common weakly-increasing (or non-decreasing) subsequences (LCWIS), for which we present an -time algorithm for the 3-letter alphabet case. For the extensively studied longest common subsequence problem, comparable speedups have not been achieved for small...

  1. Changes in job strain and subsequent weight gain

    DEFF Research Database (Denmark)

    Vesterlund, Gitte Kingo; Keller, Amélie Cléo; Heitmann, Berit Lilienthal

    2018-01-01

    in 1999 between those who were rarely v. sometimes v. often busy in 1993 (P=0·03), with the largest weight gain in individuals with sustained high busyness in both years. Loss of influence between 1993 and 1999 was associated with larger subsequent weight gain than sustained high influence (P=0......Objective: Obesity as well as job strain is increasing, and job strain might contribute to weight gain. The objective of the current study was to examine associations between longitudinal alterations in the components of job strain and subsequent weight gain. Design: The study was designed...... as a prospective cohort study with three questionnaire surveys enabling measurement of job-strain alterations over 6 years and subsequent measurements of weight gain after further 10 years of follow-up. ANCOVA and trend analyses were conducted. Job demands were measured as job busyness and speed, and control...

  2. GOGOL: ACADEMIC AND COMPLETE

    Directory of Open Access Journals (Sweden)

    Yuri V. Mann

    2016-12-01

    Full Text Available The ever-increasing international interest to Gogol explains the necessity of publishing a new edition of his works. The present Complete Collection of Gogol’s Works and Letters is an academic edition prepared and published by the A. M. Gorky Institute of World Literature of the Russian Academy of Sciences. It draws on rich experience of studying and publishing Gogol’s heritage in Russia but at the same time questions and underscores Gogol’s relevance for the modern reader and his place in the world culture of our time. It intends to fill in the gaps left by the previous scholarly tradition that failed to recognize some of Gogol’s texts as part of his heritage. Such are, for example, dedicatory descriptions in books and business notes. The present edition accounts not only for the completeness of texts but also for their place within the body of Gogol’s work, as part of his life-long creative process. By counterpoising different editions, it attempts to trace down the dynamics of Gogol’s creative thought while at the same time underscores the autonomy and relevance of each period in his career. For example, this collection publishes two different versions (editions of the same work: while the most recent version has become canonical at the expense of the preceding one, the latter still preserves its meaning and historical relevance. The present edition has the advantage over its predecessors since it has an actual, physical opportunity to erase the gaps, e.g. to publish the hitherto unpublished texts. However, the editors realize that new, hitherto unknown gaps may appear and the present edition will become, in its turn, outdated. At this point, there will be a necessity in the new edition.

  3. Exploring the academic invisible web

    OpenAIRE

    Lewandowski, Dirk

    2006-01-01

    The Invisible Web is often discussed in the academic context, where its contents (mainly in the form of databases) are of great importance. But this discussion is mainly based on some seminal research done by Sherman and Price (2001) and Bergman (2001), respectively. We focus on the types of Invisible Web content relevant for academics and the improvements made by search engines to deal with these content types. In addition, we question the volume of the Invisible Web as stated by Bergman. Ou...

  4. Exploring the academic invisible web

    OpenAIRE

    Lewandowski, Dirk; Mayr, Philipp

    2006-01-01

    Purpose: To provide a critical review of Bergman’s 2001 study on the Deep Web. In addition, we bring a new concept into the discussion, the Academic Invisible Web (AIW). We define the Academic Invisible Web as consisting of all databases and collections relevant to academia but not searchable by the general-purpose internet search engines. Indexing this part of the Invisible Web is central to scientific search engines. We provide an overview of approaches followed thus far. Design/methodol...

  5. Gaming frequency and academic performance

    OpenAIRE

    Ip, Barry; Jacobs, Gabriel; Watkins, Alan

    2008-01-01

    There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency –measured as the amount of time undergraduate students spend playing games in their free time – and their academic performance as measured by their examination marks. U...

  6. Academic Freedom as Fundamental Right

    OpenAIRE

    Cippitani, Roberto

    2015-01-01

    [EN] The paper aims at defining in particular the concept of academic freedom within the context of the European legal sources. Even though the idea of a special corporative status for professors was born during the Middle Ages, it was only during the second half of the twentieth century that the Constitutions recognised academic freedom as an individual’s legal right.. Such an individual right is regulated within the category of the freedom of expression, even if it is characteri...

  7. The effects of free recall testing on subsequent source memory.

    Science.gov (United States)

    Brewer, Gene A; Marsh, Richard L; Meeks, Joseph T; Clark-Foos, Arlo; Hicks, Jason L

    2010-05-01

    The testing effect is the finding that prior retrieval of information from memory will result in better subsequent memory for that material. One explanation for these effects is that initial free recall testing increases the recollective details for tested information, which then becomes more available during a subsequent test phase. In three experiments we explored this hypothesis using a source-monitoring test phase after the initial free recall tests. We discovered that memory is differentially enhanced for certain recollective details depending on the nature of the free recall task. Thus further research needs to be conducted to specify how different kinds of memorial details are enhanced by free recall testing.

  8. Development of IAEA description of passive safety and subsequent thoughts

    Energy Technology Data Exchange (ETDEWEB)

    Lang, P M [USDOE, Washington, DC (United States)

    1996-12-01

    The description of passive components and systems published by the IAEA in its TECDOC-626 was developed in the course of a Technical Committee Meeting held in Sweden and two subsequent Consultants Meetings held in Vienna. This description is reviewed and discussed in terms of the philosophies behind it, alternatives considered, problems encountered, and conclusions drawn. Also discussed is an Appendix to the TECDOC, which illustrates the spectrum of possibilities from passive to active by describing four typical categories of passivity. Subsequent thoughts on passive safety include a discussion of its advantages and disadvantages, concluding with a summary of current views and problems with it. (author). 8 refs.

  9. A Novel Image Encryption Algorithm Based on DNA Subsequence Operation

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2012-01-01

    Full Text Available We present a novel image encryption algorithm based on DNA subsequence operation. Different from the traditional DNA encryption methods, our algorithm does not use complex biological operation but just uses the idea of DNA subsequence operations (such as elongation operation, truncation operation, deletion operation, etc. combining with the logistic chaotic map to scramble the location and the value of pixel points from the image. The experimental results and security analysis show that the proposed algorithm is easy to be implemented, can get good encryption effect, has a wide secret key's space, strong sensitivity to secret key, and has the abilities of resisting exhaustive attack and statistic attack.

  10. Theorising and Analysing Academic Labour

    Directory of Open Access Journals (Sweden)

    Thomas Allmer

    2018-01-01

    Full Text Available The aim of this article is to contextualise universities historically within capitalism and to analyse academic labour and the deployment of digital media theoretically and critically. It argues that the post-war expansion of the university can be considered as medium and outcome of informational capitalism and as a dialectical development of social achievement and advanced commodification. The article strives to identify the class position of academic workers, introduces the distinction between academic work and labour, discusses the connection between academic, information and cultural work, and suggests a broad definition of university labour. It presents a theoretical model of working conditions that helps to systematically analyse the academic labour process and to provide an overview of working conditions at universities. The paper furthermore argues for the need to consider the development of education technologies as a dialectics of continuity and discontinuity, discusses the changing nature of the forces and relations of production, and the impact on the working conditions of academics in the digital university. Based on Erik Olin Wright’s inclusive approach of social transformation, the article concludes with the need to bring together anarchist, social democratic and revolutionary strategies for establishing a socialist university in a commons-based information society.

  11. Academic Satisfaction Level and Academic Achievement among Students at Kermanshah University of Medical Sciences: Academic Year 2015-2016

    OpenAIRE

    Khadijeh Jamshidi; Babak Mohammadi; Zahra Mohammadi; Mohammad Karimi Parviz; Roghayeh Poursaberi; Mohammad Mehdi Mohammadi

    2017-01-01

    Background: Academic satisfaction is considered one of the most important factors affecting academic achievement among students. The purpose of the present study was to determine the relationship between academic satisfaction and academic achievement among students at Kermanshah University of Medical Sciences in Iran. Methods: The present cross-sectional study was conducted with 346 student participants using stratified random sampling. The research instrument included the Student Academic Sa...

  12. Mainstreaming academic literacy teaching: Implications for how ...

    African Journals Online (AJOL)

    This article draws on research into the role of academic literacies within a range of disciplines and its implications for academic literacy teaching in Higher Education. The study explored ways of transforming current academic literacy teaching practices with a view to developing better synergy between the academic ...

  13. Noncognitive Predictors of Student Athletes' Academic Performance.

    Science.gov (United States)

    Simons, Herbert D.; Van Rheenen, Derek

    2000-01-01

    Examines the role of four noncognitive variables in predicting academic performance in 200 Division I athletes. Studies the noncognitive variables of athletic-academic commitment, feelings of being exploited, academic self-worth, self-handicapping excuses as well as several background and academic preparation variables. Finds all four noncognitive…

  14. Academic Freedom: Its Nature, Extent and Value

    Science.gov (United States)

    Barrow, Robin

    2009-01-01

    Academic freedom does not refer to freedom to engage in any speech act, but to freedom to hold any belief and espouse it in an appropriately academic manner. This freedom belongs to certain institutions, rather than to individuals, because of their academic nature. Academic freedom should be absolute, regardless of any offence it may on occasion…

  15. Sustained mental workload does not affect subsequent sleep intensity

    NARCIS (Netherlands)

    de Bruin, EA; Beersma, DGM; Daan, S; Bruin, Eveline A. de

    Mental activity is a neglected factor in sleep research. The few investigations on sleep that manipulate prior mental activity are inconclusive with respect to the possible effects of mental activity on recovery. In the present study, the effects of two levels of mental activity on subsequent sleep

  16. Outcome of Subsequent Labour After Primary Caesarean Section ...

    African Journals Online (AJOL)

    Context: Teenage mothers are at risk of numerous problems among which is cephalopeelvic disproportion or obstructed labour because of small and immature pelvis. This leads to a tendency to allowing trial of scar in subsequent pregnancies because the teenage pelvis might not have reached full capacity as at the time of ...

  17. What Employees Look for in First and Subsequent Employers.

    Science.gov (United States)

    Bewayo, Edward D.

    1986-01-01

    A questionnaire was distributed to 1,060 employees of 33 companies. It asked about motivations for choosing first-time and subsequent employers. Results showed that employees generally choose their first full-time job for advancement opportunities, benefits, and skills usage, while salary is a chief consideration for job changers. (CH)

  18. Incidence of pelvic organ prolapse repair subsequent to hysterectomy

    DEFF Research Database (Denmark)

    Lykke, Rune; Blaakær, Jan; Ottesen, Bent

    2017-01-01

    INTRODUCTION AND HYPOTHESIS: The aim of this study was to compare the incidence of subsequent pelvic organ prolapse (POP) repair in women following radical hysterectomy versus total abdominal hysterectomy. METHODS: From the Danish National Patient Registry, we collected data on all radical...

  19. Radiation degradation and the subsequent enzymatic hydrolysis of waste paper

    International Nuclear Information System (INIS)

    Kamakura, M.; Kaetsu, I.

    1982-01-01

    Various studies have been carried out to find methods for the pretreatment of waste cellulosic materials to make them more susceptible to enzymatic hydrolysis. In the work reported here, the effects of preirradiating waste papers on subsequent enzymatic hydrolysis have been studied

  20. 12 CFR 226.20 - Subsequent disclosure requirements.

    Science.gov (United States)

    2010-01-01

    ... creditor need only disclose: (1) The unpaid balance of the obligation assumed. (2) The total charges imposed by the creditor in connection with the assumption. (3) The information required to be disclosed... creditor expressly agrees in writing with a subsequent consumer to accept that consumer as a primary...

  1. Physical Restraint Initiation in Nursing Homes and Subsequent Resident Health

    Science.gov (United States)

    Engberg, John; Castle, Nicholas G.; McCaffrey, Daniel

    2008-01-01

    Purpose: It is widely believed that physical restraint use causes mental and physical health decline in nursing home residents. Yet few studies exist showing an association between restraint initiation and health decline. In this research, we examined whether physical restraint initiation is associated with subsequent lower physical or mental…

  2. Weight at birth and subsequent fecundability: a prospective cohort study

    DEFF Research Database (Denmark)

    Nielsen, Cathrine Wildenschild; Hammerich Riis, Anders; Ehrenstein, Vera

    2014-01-01

    OBJECTIVE: To examine the association between a woman's birth weight and her subsequent fecundability. METHOD: In this prospective cohort study, we included 2,773 Danish pregnancy planners enrolled in the internet-based cohort study "Snart-Gravid", conducted during 2007-2012. Participants were 18...

  3. Initial and subsequent location choices of immigrants to the Netherlands

    NARCIS (Netherlands)

    Zorlu, A.; Mulder, C.H.

    2008-01-01

    The initial settlement behaviour and the subsequent mobility of immigrants who arrived in the Netherlands in 1999 are examined using rich administrative individual data. The study considers the settlement patterns of immigrants from various countries of origin who entered the country as labour,

  4. Oro-cecal transit time : influence of a subsequent meal

    NARCIS (Netherlands)

    Priebe, MG; Wachters-Hagedoorn, RE; Stellaard, F; Heiner, AM; Elzinga, H; Vonk, RJ

    Background Small intestinal and oro-cecal transit time (OCTT) is determined for clinical diagnostics and research purposes. Experimental protocols used vary with respect to the inclusion of a subsequent meal during the test period. This study was conducted to elucidate whether the ingestion of a

  5. Effect of winter nutritional levels on subsequent growth of beef ...

    African Journals Online (AJOL)

    Effect of winter nutritional levels on subsequent growth of beef heifers in the Highland Sourveld of Natal. ... Teen 'n lae veebelading van 0,75 GVE/ha (vir die weiperiode) op somerveld, het verse betekenisvol (P < 0,01) meer in massa toegeneem vergeleke met 'n hoë veebelading (1,25 GVE/ha). Binne elk van die ...

  6. Academic training: Applied superconductivity

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

  7. Measurement of buoyancy driven convection and microaccelerations on board International Space Station with the use of convection sensor Dacon-M

    Science.gov (United States)

    Putin, Gennady; Belyaev, Mikhail; Babushkin, Igor; Glukhov, Alexander; Zilberman, Evgeny; Maksimova, Marina; Ivanov, Alexander; Sazonov, Viktor; Nikitin, Sergey; Zavalishin, Denis; Polezhaev, Vadim

    The system for studying buoyancy driven convection and low-frequency microaccelerations aboard spacecraft is described. The system consists of: 1. facility for experimentation on a spaceship - the convection sensor and electronic equipment for apparatus control and for acquisition and processing of relevant information; 2. facility for ground-based laboratory modeling of various fluid motion mechanisms in application to orbital flight environment; 3. the system for computer simulations of convection processes in a fluid cell of a sensor using the data on microaccelerations obtained by accelerometers and another devices aboard the orbital station. The arrangement and functioning of the sensor and control hardware are expounded. The results of terrestrial experiments performed in order to determine the sensitivity of the sensor are described. The results of experiments carried out in 2008 - 2011 with the “DACON-M” apparatus in different modules of the Russian Segment of International Space Station and for various regimes of Station activity are reported. Experimental data recorded by “DACON-M” apparatus have been compared with the calculations of acceleration components based on the telemetry information about the orientation of the Station.

  8. Development and Assessment of CFD Models Including a Supplemental Program Code for Analyzing Buoyancy-Driven Flows Through BWR Fuel Assemblies in SFP Complete LOCA Scenarios

    Science.gov (United States)

    Artnak, Edward Joseph, III

    This work seeks to illustrate the potential benefits afforded by implementing aspects of fluid dynamics, especially the latest computational fluid dynamics (CFD) modeling approach, through numerical experimentation and the traditional discipline of physical experimentation to improve the calibration of the severe reactor accident analysis code, MELCOR, in one of several spent fuel pool (SFP) complete loss-ofcoolant accident (LOCA) scenarios. While the scope of experimental work performed by Sandia National Laboratories (SNL) extends well beyond that which is reasonably addressed by our allotted resources and computational time in accordance with initial project allocations to complete the report, these simulated case trials produced a significant array of supplementary high-fidelity solutions and hydraulic flow-field data in support of SNL research objectives. Results contained herein show FLUENT CFD model representations of a 9x9 BWR fuel assembly in conditions corresponding to a complete loss-of-coolant accident scenario. In addition to the CFD model developments, a MATLAB based controlvolume model was constructed to independently assess the 9x9 BWR fuel assembly under similar accident scenarios. The data produced from this work show that FLUENT CFD models are capable of resolving complex flow fields within a BWR fuel assembly in the realm of buoyancy-induced mass flow rates and that characteristic hydraulic parameters from such CFD simulations (or physical experiments) are reasonably employed in corresponding constitutive correlations for developing simplified numerical models of comparable solution accuracy.

  9. [The relationship between academic self-efficacy and academic burnout in medical students].

    Science.gov (United States)

    Lee, Su Hyun; Jeon, Woo Taek

    2015-03-01

    The purpose of this study was to examine the correlation between academic burnout and academic self-efficacy in medical students. The study group comprised 446 students in years 1 to 4 of medical school. They were asked to rate their academic burnout and academic self-efficacy on a scale. The data were analyzed by multivariate analysis of variance and regression analysis. Academic self-efficacy was correlated negatively with academic burnout explaining 37% of academic burnout. Academic self-efficacy (especially self-confidence) had the greatest effect on academic burnout. The implications of these results are discussed in terms of an evaluation and support system for students.

  10. Age at First Concussion Influences the Number of Subsequent Concussions.

    Science.gov (United States)

    Schmidt, Julianne D; Rizzone, Katherine; Hoffman, Nicole L; Weber, Michelle L; Jones, Courtney; Bazarian, Jeff; Broglio, Steven P; McCrea, Michael; McAllister, Thomas W

    2018-04-01

    Individuals who sustain their first concussion during childhood may be at greater risk of sustaining multiple concussions throughout their lifetime because of a longer window of vulnerability. This article aims to estimate the association between age at first concussion and number of subsequent concussions. A total of 23,582 collegiate athletes from 26 universities and military cadets from three military academies completed a concussion history questionnaire (65% males, age 19.9 ± 1.4 years). Participants self-reported concussions and age at time of each injury. Participants with a history of concussion (n = 3,647, 15.5%) were categorized as having sustained their first concussion during childhood (less than ten years old) or adolescence (≥10 and ≤18 years old). Poisson regression was used to model age group (childhood, adolescence) predicting the number of subsequent concussions (0, 1, 2+). A second Poisson regression was developed to determine whether age at first concussion predicted the number of subsequent concussions. Participants self-reporting their first concussion during childhood had an increased risk of subsequent concussions (rate ratio = 2.19, 95% confidence interval: 1.82, 2.64) compared with participants self-reporting their first concussion during adolescence. For every one-year increase in age at first concussion, we observed a 16% reduction in the risk of subsequent concussion (rate ratio = 0.84, 95% confidence interval: 0.82, 0.86). Individuals self-reporting a concussion at a young age sustained a higher number of concussions before age 18. Concussion prevention, recognition, and reporting strategies are of particular need at the youth level. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Sleep and academic performance in undergraduates: a multi-measure, multi-predictor approach.

    Science.gov (United States)

    Gomes, Ana Allen; Tavares, Jos; de Azevedo, Maria Helena P

    2011-11-01

    The present study examined the associations of sleep patterns with multiple measures of academic achievement of undergraduate university students and tested whether sleep variables emerged as significant predictors of subsequent academic performance when other potential predictors, such as class attendance, time devoted to study, and substance use are considered. A sample of 1654 (55% female) full-time undergraduates 17 to 25 yrs of age responded to a self-response questionnaire on sleep, academics, lifestyle, and well-being that was administered at the middle of the semester. In addition to self-reported measures of academic performance, a final grade for each student was collected at the end of the semester. Univariate analyses found that sleep phase, morningness/eveningness preference, sleep deprivation, sleep quality, and sleep irregularity were significantly associated with at least two academic performance measures. Among 15 potential predictors, stepwise multiple regression analysis identified 5 significant predictors of end-of-semester marks: previous academic achievement, class attendance, sufficient sleep, night outings, and sleep quality (R(2)=0.14 and adjusted R(2)=0.14, F(5, 1234)= 40.99, p academic achievement and the remaining sleep variables as well as the academic, well-being, and lifestyle variables lost significance in stepwise regression. Together with class attendance, night outings, and previous academic achievement, self-reported sleep quality and self-reported frequency of sufficient sleep were among the main predictors of academic performance, adding an independent and significant contribution, regardless of academic variables and lifestyles of the students.

  12. Gender differences in promotion and scholarly impact: an analysis of 1460 academic ophthalmologists.

    Science.gov (United States)

    Lopez, Santiago A; Svider, Peter F; Misra, Poonam; Bhagat, Neelakshi; Langer, Paul D; Eloy, Jean Anderson

    2014-01-01

    In recent years, gender differences in academic promotion have been documented within surgical fields. To the best of our knowledge, gender discrepancies in association with scholarly productivity have not been well assessed among academic ophthalmologists. Because research productivity is strongly associated with academic career advancement, we sought to determine whether gender differences in scholarly impact, measured by the h-index, exist among academic ophthalmologists. Academic rank and gender were determined using faculty listings from academic ophthalmology departments. h-index and publication experience (in years) of faculty members were determined using the Scopus database. Academic medical center. From assistant professor through professor, the h-index increased with subsequent academic rank (p 0.05). Overall, men had higher h-indices (h = 10.4 ± 0.34 standard error of mean) than women (h = 6.0 ± 0.38 standard error of mean), a finding that was only statistically significant among assistant professors in a subgroup analysis. Women were generally underrepresented among senior positions. When controlling for publication range (i.e., length of time publishing), men had higher h-indices among those with 1 to 10 years of publication experience (p careers. Women in academic ophthalmology continue to be underrepresented among senior faculty. Although women surpass men in scholarly productivity during the later stages of their careers, low scholarly impact during the earlier stages may impede academic advancement and partly explain the gender disparity in senior academic positions. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  13. Academic Mobility, Transnational Identity Capital, and Stratification under Conditions of Academic Capitalism

    Science.gov (United States)

    Kim, Terri

    2017-01-01

    Academic mobility has existed since ancient times. Recently, however, academic mobility--the crossing of international borders by academics who then work "overseas"--has increased. Academics and the careers of academics have been affected by governments and institutions that have an interest in coordinating and accelerating knowledge…

  14. Relationship of Perceived Stress, Perfectionism and Social Support with Students’ Academic Burnout and -Academic Performance

    Directory of Open Access Journals (Sweden)

    Pourseyyed SM

    2015-07-01

    Conclusion: Perceived stress has negative direct relationship with social support and positive direct relationship with academic burnout. Social support also has positive direct relationship with academic performance. Relationship of maladaptive perfectionism with academic burnout and also the relationship of adaptive perfectionism with academic performance is direct positive. Relationship of perceived stress with academic performance is indirect mediated by social support.

  15. Academics and Citizens Working Together

    Science.gov (United States)

    Bogen, D., Jr.

    2017-12-01

    Traditionally Academics and citizens have contributed to each other lives but friction has always existed between the two. When there is a hostile relationship between community members and Academics, the collection of data suffers, which in returns hurts the potential solutions to community problems. Combining Community Based Participatory Research and the BISCO Community Organizing Model, {Listens, Identify, Research, offer solution}, these frictions can be limited, creating better working environments, and producing better data. Helping create and participating in workgroups, including NGO's, Academics and Citizens leaders, have produce better working environments. Using these methods within the work groups I observed, relationships being form between Academics and Citizens. Some of the relationships were both public and private. The workgroups that created space for professional and personal stories telling produced the most relationships. Listening and understand each other, before research have proven to be successful in producing trust between Academics and Citizens. When Academics and Citizens developed trust between themselves, each party respects the other limitation. Knowing each limitation is perhaps the most key element in working together, which eliminates over promises and culture hindrance within the community. It's amazing like getting the answers to the test before you take it. The project becomes richer in design, when there is trust in the process before it begins. Working together to eliminating potential road blocks ahead of time, enhance the project chances to produce, richer data.Academics cannot produce good data if citizens withhold information and citizens cannot solve their social ills if they do not have good data, in short we need each other.

  16. A Case Study and Analysis of a Successful and Collaborative Student-Centered Textbook Reserve Program in a Mid-Size Academic Library

    Science.gov (United States)

    Schlak, Timothy M.; Johnston, Bruce

    2018-01-01

    This article presents an innovative textbook reserve program at a mid-sized academic library. Research conducted subsequent to the program's launch showed a positive correlation between students' use of the program and their perceived academic success. In addition, the program has proved effective at helping students with college affordability.…

  17. Challenges in contemporary academic neurosurgery.

    Science.gov (United States)

    Black, Peter M

    2006-03-01

    Traditionally, the ideal academic neurosurgeon has been a "quadruple threat," with excellence in clinical work, teaching, research, and administration. This tradition was best exemplified in Harvey Cushing, who developed the field of neurosurgery 90 years ago. This paradigm will probably have to change as academic neurosurgeons face major challenges. In patient care, these include increasing regulatory control, increasing malpractice costs, consolidation of expensive care in academic centers, and decreasing reimbursement; in resident teaching, work hour limitations and a changing resident culture; in research, the increasing dominance of basic scientists in governmental funding decisions and decreased involvement of neurosurgeons in scientific review committees; and in administration, problems of relationships in the workplace, patient safety, and employment compliance in an increasingly bureaucratic system. To meet these challenges, the new academic neurosurgeon will probably not be a quadruple threat personally but will be part of a quadruple threat in a department and institution. Neurosurgeons in such a setting will have to work with hospital, medical school, and national and international groups to address malpractice, reimbursement, subspecialization, and training problems; find supplemental sources of income through grants, development funds, and hospital support; lead in the development of multidisciplinary centers for neuroscience, brain tumor, spine, and other initiatives; and focus on training leaders for hospital, regional, and national groups to reconfigure neurosurgery. Collaboration, flexibility, and leadership will be characteristic of the academic neurosurgeon in this new era.

  18. Different Roads to Academic Entrepreneurship

    Science.gov (United States)

    Venkatesan, T. Venky

    There has been a sea change over the last few decades in the way academic institutions view entrepreneurial activities of the faculty and the role of the Institution in fostering an ecosystem conducive to such activities. This has become a global phenomenon and many of the leading Institutions in Europe and Asia are also beginning to replicate the model of the Boston or Silicon Valley academic Institutions. While this is an opportunity for the innovative, entrepreneurial faculty member it also presents a significant dilemma in terms of how one manages such extra-curricular activities with minimal detriment to one's academic program. In my talk I will discuss a variety of models that are available to the academic entrepreneur, their pluses and minuses and also some of the critical knowledge one needs to understand about the world of entrepreneurship in general. I will use examples from several of my colleagues' startups and my own experience in running a company for over three decades maintaining an academic life.

  19. The Interaction of Publications and Appointments: New Evidence on Academic Economists in Germany

    Science.gov (United States)

    Beckmann, Klaus; Schneider, Andrea

    2013-01-01

    Using a new panel data set comprising publication and appointment data for 889 German academic economists over a quarter of a century, we confirm the familiar hypothesis that publications are important for professorial appointments, but find only a small negative effect of appointments on subsequent research productivity, in particular if one…

  20. Mark Olssen on Neoliberalisation of Higher Education and Academic Lives: An Interview

    Science.gov (United States)

    Raaper, Rille; Olssen, Mark

    2016-01-01

    This article is based on an interview conducted with Mark Olssen in October 2014, and the subsequent discussions. These conversations invited Olssen to reflect on his experiences of neoliberalism as a practising academic who has worked in the UK for some 14 years, and also to comment as a researcher and writer who is well known for his work on…

  1. Work-Life Balance among academic staff of the University of Lagos ...

    African Journals Online (AJOL)

    Work-Life Balance among academic staff of the University of Lagos. ... Abstract. Work-life balance is associated with the maintenance of stability in both one's professional and personal life. It is key to the welfare and, subsequently, job satisfaction and productivity of employees. It is against this understanding that this study ...

  2. Academic Mathematicians' Dispositions toward Software Use in Mathematics Instruction: What Are the Underlying Reasons?

    Science.gov (United States)

    Khoshaim, Heba Bakr

    2012-01-01

    Academic mathematicians' opinions are divided regarding software use in undergraduate mathematics instruction. This study explored these opinions through interviews and a subsequent survey of mathematicians at PhD-granting institutions in the United States regarding their dispositions and the underlying attitudes. Most prior related work had…

  3. Young Children's Interest-Oriented Activity and Later Academic Self-Regulation Strategies in Kindergarten

    Science.gov (United States)

    Neitzel, Carin; Alexander, Joyce M.; Johnson, Kathy E.

    2016-01-01

    This study investigated children's interest-based activities in the home during the preschool years and their subsequent academic self-regulation behaviors in school. Children's home activities were tracked for 1 year prior to kindergarten entry. Based on their profiles of activities, children (109) were assigned to one of four interest groups:…

  4. Will the Liberal Arts Survive the Bronze Age of American Academe?

    Science.gov (United States)

    Kimball, Bruce A.

    2015-01-01

    Kimball begins this essay by comparing the start of the "golden age" of liberal arts education as the period between about 1950 and 1975 when American higher education's revenue and enrollments of colleges and universities grew enormously. During the subsequent silver age of academe, ending in the Great Recession of 2008-2009,…

  5. Self-Concept and Academic Achievement: A Meta-Analysis of Longitudinal Relations

    Science.gov (United States)

    Huang, Chiungjung

    2011-01-01

    The relation between self-concept and academic achievement was examined in 39 independent and longitudinal samples through the integration of meta-analysis and path analysis procedures. For relations with more than 3 independent samples, the mean observed correlations ranged from 0.20 to 0.27 between prior self-concept and subsequent academic…

  6. The academic value of rehabilitation medicine meetings.

    Science.gov (United States)

    Sivan, Manoj; Smith, Matthew; Bavikatte, Ganesh; Bradley, Lloyd

    2010-01-01

    Twice-yearly meetings of The British Society of Rehabilitation Medicine (BSRM) take place at which posters and free papers are generated, as abstracts, to present novel research findings, audits and case reports. The aim of this study was to evaluate the academic value of these meetings, by determining the subsequent rate of publication in peer-reviewed journals of abstracts presented. This was compared to the publication rate of other European medical specialist society meetings. The authors used MEDLINE, PubMed and Google Scholar search engines to look for publication of abstracts presented at BSRM meetings within peer-reviewed journals over a 7-year period (2000-2006). The abstracts were categorised into sub-groups (original study, audit, review, case report and service description) to determine which type was more likely to be published. The above databases were used also to extract studies on publication rate of other medical specialties in Europe. In 7 years, a total of 251 abstracts (of which 152 are original studies) have been presented as free papers or posters in a total of 13 meetings. The publication rate for the described study categories were: total 34%, original study 52%, review 50%, case report 5%, audit 0% and service description 0%. Publication rates from other specialist meetings in Europe range from 10% to 70%. The average publication rate for an abstract submitted to a BSRM meeting is 34% for any abstract and 52% for an original study suggesting that the meeting is generating abstracts of comparable academic interest to other specialist societies.

  7. Histopathologic changes in fallopian tubes subsequent to sterilization procedures.

    Science.gov (United States)

    Stock, R J

    1983-01-01

    Longitudinal serial and serial step sections of fallopian tubes from more than 100 patients, subsequent to tubal sterilization procedures, were examined. Thirteen of these patients had pregnancies following their sterilizations. The histologic findings at the previous surgical sites were compatible with what would be expected for a normal healing process. Evidence for a unique tubal epithelial process, as suggested by the terms "endosalpingiosis" or "recanalization," was lacking. Likewise, the author found no evidence of tuboperitoneal fistula formation and/or the subsequent occurrence of pregnancy secondary to localized endometriosis. The histologic notations of proximal luminal dilatation, plical attenuation, chronic inflammatory infiltrates with pseudopolyp formation, and the findings of plical thickening in the distal segment of remaining tube after an interruption type of procedure seem to be associated with the length of time from the sterilization procedure. These may be factors related to the apparent reduced success rate, with time, of microsurgical reanastomotic procedures.

  8. Medical abortion and the risk of subsequent adverse pregnancy outcomes

    DEFF Research Database (Denmark)

    Virk, Jasveer; Zhang, Jun; Olsen, Jørn

    2007-01-01

    BACKGROUND: The long-term safety of surgical abortion in the first trimester is well established. Despite the increasing use of medical abortion (abortion by means of medication), limited information is available regarding the effects of this procedure on subsequent pregnancies. METHODS: We...... identified all women living in Denmark who had undergone an abortion for nonmedical reasons between 1999 and 2004 and obtained information regarding subsequent pregnancies from national registries. Risks of ectopic pregnancy, spontaneous abortion, preterm birth (at ... weight (abortion were compared with risks in women who had had a first-trimester surgical abortion. RESULTS: Among 11,814 pregnancies in women who had had a previous first-trimester medical abortion (2710 women...

  9. Laser Induced Selective Activation For Subsequent Autocatalytic Electroless Plating

    DEFF Research Database (Denmark)

    Zhang, Yang

    . The third hypothesis is that the activation and rinsing process can be described by diffusion. This hypothesis is proved using Fick’s diffusion laws combined with the short-time-plating experiment. The influence of laser parameters on the surface structure is investigated for Nd:YAG, UV, and fiber lasers......The subject of this PhD thesis is “Laser induced selective activation for subsequent autocatalytic electroless plating.” The objective of the project is to investigate the process chains for micro structuring of polymer surfaces for selective micro metallization. Laser induced selective activation...... (LISA) is introduced and studied as a new technique for producing 3D moulded interconnect devices (3D-MIDs). This technique enables the metallization of polymer surface modified by laser and subsequently activated by a PdCl2/SnCl2 system. Various technologies exist on an industrial level...

  10. Separation of trace uranium from plutonium for subsequent analysis

    International Nuclear Information System (INIS)

    Marsh, S.F.

    1980-08-01

    Trace uranium quantities are separated from plutonium metal and plutonium oxide for subsequent analysis. Samples are dissolved in hydrobromic acid or a hydrobromic acid-hydrofluoric acid mixture. The U(VI)-halide complex is separated from nonsorbed Pu(III) on an anion exchange column using sequential washes of 9M HBr, a 0.1M HI-12M HCl mixture and 0.1M HCl

  11. Global Brain Dynamics During Social Exclusion Predict Subsequent Behavioral Conformity

    OpenAIRE

    Wasylyshyn, Nick; Hemenway, Brett; Garcia, Javier O.; Cascio, Christopher N.; O'Donnell, Matthew Brook; Bingham, C. Raymond; Simons-Morton, Bruce; Vettel, Jean M.; Falk, Emily B.

    2017-01-01

    Individuals react differently to social experiences; for example, people who are more sensitive to negative social experiences, such as being excluded, may be more likely to adapt their behavior to fit in with others. We examined whether functional brain connectivity during social exclusion in the fMRI scanner can be used to predict subsequent conformity to peer norms. Adolescent males (N = 57) completed a two-part study on teen driving risk: a social exclusion task (Cyberball) during an fMRI...

  12. Subsequent Shoulder Surgery After Isolated Arthroscopic SLAP Repair.

    Science.gov (United States)

    Mollon, Brent; Mahure, Siddharth A; Ensor, Kelsey L; Zuckerman, Joseph D; Kwon, Young W; Rokito, Andrew S

    2016-10-01

    To quantify the incidence of and identify the risk factors for subsequent shoulder procedures after isolated SLAP repair. New York's Statewide Planning and Research Cooperative System database was searched between 2003 and 2014 to identify individuals with the sole diagnosis of a SLAP lesion who underwent isolated arthroscopic SLAP repair. Patients were longitudinally followed up for a minimum of 3 years to analyze for subsequent ipsilateral shoulder procedures. Between 2003 and 2014, 2,524 patients met our inclusion criteria. After 3 to 11 years of follow-up, 10.1% of patients (254 of 2,524) underwent repeat surgical intervention on the same shoulder as the initial SLAP repair. The mean time to repeat shoulder surgery was 2.3 ± 2.1 years. Subsequent procedures included subacromial decompression (35%), debridement (26.7%). repeat SLAP repair (19.7%), and biceps tenodesis or tenotomy (13.0%). After isolated SLAP repair, patients aged 20 years or younger were more likely to undergo arthroscopic Bankart repair (odds ratio [OR], 2.91; 95% confidence interval [CI], 1.36-6.21; P = .005), whereas age older than 30 years was an independent risk factor for subsequent acromioplasty (OR, 2.3; 95% CI, 1.4-3.7; P surgery after isolated SLAP repair, often related to an additional diagnosis, suggesting that clinicians should consider other potential causes of shoulder pain when considering surgery for patients with SLAP lesions. In addition, the number of isolated SLAP repairs performed has decreased over time, and management of failed SLAP repair has shifted toward biceps tenodesis or tenotomy over revision SLAP repair in more recent years. Level III, case-control study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  13. Orca Behavior and Subsequent Aggression Associated with Oceanarium Confinement

    OpenAIRE

    Anderson, Robert; Waayers, Robyn; Knight, Andrew

    2016-01-01

    Simple Summary Orca behaviors interacting with humans within apparent friendship bonds are reviewed, and some impediments to the human evaluation of delphinid intelligence are discussed. The subsequent involvement of these orcas and their offspring in aggressive incidents with humans is also documented and examined. This is particularly relevant given that the highest recorded rates of aggressive incidents have occurred among orcas who had previously established unstructured human friendship ...

  14. Academic Training: Astronomy from Space

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 14, 15, 16, 18 March from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 Astronomy from Space by T. Courvoisier / Observatoire de Genève In the very wide field of High Energy astrophysics we will select a number of topics that range from the source of radiative energy in the deep potential well around Schwarzschild and Kerr black holes and the basics of accretion disks around compact objects to the description and (where possible) the understanding of binary systems including a compact object (neutron star or black hole), of Active Galactic Nuclei and of gamma ray bursts. The approach that is chosen aims at giving an understanding of the most important phenomenologies encountered in high energy astrophysics rather than a detailed knowledge of one specific topic. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

  15. Academic citizenship beyond the campus

    DEFF Research Database (Denmark)

    Nørgård, Rikke Toft; Bengtsen, Søren Smedegaard

    2016-01-01

    hrough combining theories of space and place with works on institutional being, virtues and modes of becoming, this article develops and promotes academic citizenship as the formation of dwelling, being and becoming on the placeful university beyond the campus. We argue that this is a prerequisite......-imagine the possibilities of the university to integrate with people and society through dialogue and placeful-ness. Accordingly, supporting academic citizenship entails designing for the placeful university – a university that invites and promotes openness, dialogue, democracy, mutual integration, care and joint...... responsibility. Consequently, a comprehension of the placeful university is developed in the article to make the potentiality of academic citizenship for the future university emerge....

  16. 'Academic literacies approaches to genre'?

    Directory of Open Access Journals (Sweden)

    Brian Street

    Full Text Available I provide an overview of approaches to writing referred to as 'academic literacies' building on broader traditions, such as New Literacy Studies, and I draw out the relevance of such traditions for the ways in which lecturers provide support to their students with regard to the writing requirements of the University. I offer three case studies of the application of academic literacies approaches to programmes concerned with supporting student writing, in the UK and the USA. I briefly conclude by asking how far these accounts and this work can be seen to bring together many of the themes raised at SIGET conferences - including academic literacies and its relation to genre theories - and express the hope that it opens up trajectories for future research and collaboration of the kind they were founded to develop.

  17. Academic Training: Gravitational Waves Astronomy

    CERN Multimedia

    2006-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 16, 17, 18 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Gravitational Waves Astronomy M. LANDRY, LIGO Hanford Observatory, Richland, USA Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www...

  18. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    International Nuclear Information System (INIS)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo; Takemura, Taro; Hanagata, Nobutaka

    2011-01-01

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift (Δf) and dissipation energy shift (ΔD), and the viscoelastic change as ΔD-Δf plot. The Col adsorption showed larger Δf and ΔD values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The ΔD-Δf plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  19. Effect of skipping breakfast on subsequent energy intake.

    Science.gov (United States)

    Levitsky, David A; Pacanowski, Carly R

    2013-07-02

    The objective was to examine the effect of consuming breakfast on subsequent energy intake. Participants who habitually ate breakfast and those who skipped breakfast were recruited for two studies. Using a randomized crossover design, the first study examined the effect of having participants consume either (a) no breakfast, (b) a high carbohydrate breakfast (335 kcals), or (c) a high fiber breakfast (360 kcals) on three occasions and measured ad libitum intake at lunch. The second study again used a randomized crossover design but with a larger, normal carbohydrate breakfast consumed ad libtum. Intake averaged 624 kcals and subsequent food intake was measured throughout the day. Participants ate only foods served from the Cornell Human Metabolic Research Unit where all foods were weighed before and after consumption. In the first study, neither eating breakfast nor the kind of breakfast consumed had an effect on the amount consumed at lunch despite a reduction in hunger ratings. In the second study, intake at lunch as well as hunger ratings were significantly increased after skipping breakfast (by 144 kcal), leaving a net caloric deficit of 408 kcal by the end of the day. These data are consistent with published literature demonstrating that skipping a meal does not result in accurate energy compensation at subsequent meals and suggests that skipping breakfast may be an effective means to reduce daily energy intake in some adults. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Subsequent publication of oral and maxillofacial surgery meeting abstracts.

    Science.gov (United States)

    Rodriguez, Joseph L; Laskin, Daniel M

    2012-05-01

    Previous studies in various medical specialties have shown that fewer than 50% of abstracts presented at meetings are subsequently published. The purpose of the present study was to determine the publication rate of abstracts presented at the annual meetings of the American Association of Oral and Maxillofacial Surgeons. The titles and authors of the abstracts from all oral abstract session presentations and posters by American contributors were collected from the Final Programs of the American Association of Oral and Maxillofacial Surgeons annual meetings for 2006 to 2009. A PubMed search for published articles through December 2010 was then performed using the authors' names, abstract titles, and key words. A total of 311 abstract presentations were done at the 4 annual meetings. Of these, only 85 (24%) were subsequently published. No difference was found between abstracts from oral or poster presentations. Most of the articles were published in the Journal of Oral and Maxillofacial Surgery. Because of deficiencies that can occur in abstracts and the need to disseminate the information they contain, it is important to take the appropriate measures to ensure that full articles are subsequently published. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Protein Adsorption and Subsequent Fibroblasts Adhesion on Hydroxyapatite Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tagaya, Motohiro; Ikoma, Toshiyuki; Yoshioka, Tomohiko; Tanaka, Junzo [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo, Tokyo 152-8550 (Japan); Takemura, Taro; Hanagata, Nobutaka, E-mail: tagaya.m.aa@m.titech.ac.jp [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-10-29

    Quartz crystal microbalance with dissipation (QCM-D) technique was employed for protein adsorption and subsequent fibroblast adhesion on hydroxyapatite (HAp) nanocrystals. The pre-adsorption of three proteins (albumin (BSA) or fibronectin (Fn) or collagen (Col)) and subsequent adsorption of fetal bovine serum (FBS), and the adhesion of fibroblasts on the surface were in situ monitored, and evaluated with the frequency shift ({Delta}f) and dissipation energy shift ({Delta}D), and the viscoelastic change as {Delta}D-{Delta}f plot. The Col adsorption showed larger {Delta}f and {Delta}D values compared with BSA or Fn adsorption, and the subsequent FBS adsorption depended on the pre-adsorbed proteins. The {Delta}D-{Delta}f plot of the cell adhesion also showed the different behaviour on the surfaces, indicating the process affected by cell-protein interactions. The confocal laser scanning microscope images of adherent cells showed the different morphology and pseudopod on the surfaces. The cells adhered on the surfaces modified with Fn and Col had the uniaxially expanded shape with fibrous pseudopods, while those modified with BSA had round shape. The different cell-protein interaction would cause the arrangement of extracellular matrix and cytoskeleton changes at the interfaces.

  2. Influences of multisensory experience on subsequent unisensory processing

    Directory of Open Access Journals (Sweden)

    Ladan eShams

    2011-10-01

    Full Text Available Multisensory perception has been the focus of intense research in recent years. It is now well established that crossmodal interactions are ubiquitous in perceptual processing and endow the system with improved precision, accuracy, processing speed, etc. While these findings have shed much light on principles and mechanisms of perception, ultimately it is not very surprising that multiple sources of information provide benefits in performance compared to a single source of information.Here, we argue that the more surprising recent findings are those showing that multisensory experience also influences the subsequent unisensory processing. For example, exposure to auditory-visual stimuli, can change the way auditory or visual stimuli are processed subsequently even in isolation. We review three sets of findings that represent three different types of learning ranging from perceptual learning, to sensory recalibration, to associative learning. In all these cases exposure to multisensory stimuli profoundly influences the subsequent unisensory processing. This diversity of phenomena may suggest that continuous modification of unisensory representations by multisensory relationships may be a general learning strategy used by the brain.

  3. Infant and child deaths: Parent concerns about subsequent pregnancies.

    Science.gov (United States)

    Brooten, Dorothy; Youngblut, JoAnne M; Hannan, Jean; Caicedo, Carmen; Roche, Rosa; Malkawi, Fatima

    2015-12-01

    Examine parents' concerns about subsequent pregnancies after experiencing an infant or child death (newborn to 18 years). Thirty-nine semistructured parent (white, black, Hispanic) interviews 7 and 13 months post infant/child death conducted in English and/or Spanish, audio-recorded, transcribed, and content analyzed. Mothers' mean age was 31.8 years, fathers' was 39 years; 11 parents were white, 16 black, and 12 Hispanic. Themes common at 7 and 13 months: wanting more children; fear, anxiety, scared; praying to God/God's will; thinking about/keeping the infant's/child's memory and at 7 months importance of becoming pregnant for family members; and at 13 months happy about a new baby. Parents who lost a child in neonatal intensive care unit (NICU) commented more than those who lost a child in pediatric intensive care unit (PICU). Black and Hispanic parents commented more on praying to God and subsequent pregnancies being God's will than white parents. Loss of an infant/child is a significant stressor on parents with documented negative physical and mental health outcomes. Assessing parents' subsequent pregnancy plans, recognizing the legitimacy of their fears about another pregnancy, discussing a plan should they encounter problems, and carefully monitoring the health of all parents who lost an infant/child is an essential practitioner role. ©2015 American Association of Nurse Practitioners.

  4. Global brain dynamics during social exclusion predict subsequent behavioral conformity.

    Science.gov (United States)

    Wasylyshyn, Nick; Hemenway Falk, Brett; Garcia, Javier O; Cascio, Christopher N; O'Donnell, Matthew Brook; Bingham, C Raymond; Simons-Morton, Bruce; Vettel, Jean M; Falk, Emily B

    2018-02-01

    Individuals react differently to social experiences; for example, people who are more sensitive to negative social experiences, such as being excluded, may be more likely to adapt their behavior to fit in with others. We examined whether functional brain connectivity during social exclusion in the fMRI scanner can be used to predict subsequent conformity to peer norms. Adolescent males (n = 57) completed a two-part study on teen driving risk: a social exclusion task (Cyberball) during an fMRI session and a subsequent driving simulator session in which they drove alone and in the presence of a peer who expressed risk-averse or risk-accepting driving norms. We computed the difference in functional connectivity between social exclusion and social inclusion from each node in the brain to nodes in two brain networks, one previously associated with mentalizing (medial prefrontal cortex, temporoparietal junction, precuneus, temporal poles) and another with social pain (dorsal anterior cingulate cortex, anterior insula). Using predictive modeling, this measure of global connectivity during exclusion predicted the extent of conformity to peer pressure during driving in the subsequent experimental session. These findings extend our understanding of how global neural dynamics guide social behavior, revealing functional network activity that captures individual differences.

  5. ACADEMIC ADVISORS: VALUES EDUCATED LEADERS

    Directory of Open Access Journals (Sweden)

    Brizeida Mijares

    2008-07-01

    Full Text Available The purpose of this article is to study the academic advisors’ profile from the attitudes in the learning process view point, being the center of which the need that as an educator, the advisor has to be a leader educated in values. The research was documental, according to the theoretical contributions of Arana and Batista (2006,  Ortega and Minguez (2001 and Denis (2000, among others. It is concluded that an academic advisor in values allows individual and collective trasnformation and an education without values as its center, it is a hollow and useless education.

  6. Academic Superheroes? A Critical Analysis of Academic Job Descriptions

    Science.gov (United States)

    Pitt, Rachael; Mewburn, Inger

    2016-01-01

    For over a decade, debate has raged about the nature and purpose of the PhD, including its role as preparation for working in academia. Academic work has changed a great deal in the last 60 years, yet our doctoral curriculum has remained relatively static. While there is increasing interest in matching PhD programmes to "real world"…

  7. The Effect of POGIL on Academic Performance and Academic Confidence

    Science.gov (United States)

    De Gale, S.; Boisselle, L. N.

    2015-01-01

    POGIL (Process Oriented Guided Inquiry Learning) is a collaborative learning technique that employs guided inquiry within a cyclic system of exploration, concept invention, and application. This action research explores students' academic performance on a unit of organic chemistry work taught using POGIL, in addition to the effect of POGIL on…

  8. Academic Governance and Academic Reform: Legitimacy and Energy.

    Science.gov (United States)

    Peter, Kenneth B.; Bain, Linda L.

    1998-01-01

    A thorough review and revision of curriculum at San Jose State University (California) illustrates that the modern university can achieve major internal academic reforms when two important conditions are met: legitimacy and energy. These two concepts are defined and practical illustrations are drawn from the institution's recent experience in…

  9. Task-focused behavior mediates the associations between supportive interpersonal environments and students' academic performance.

    Science.gov (United States)

    Kiuru, Noona; Pakarinen, Eija; Vasalampi, Kati; Silinskas, Gintautas; Aunola, Kaisa; Poikkeus, Anna-Maija; Metsäpelto, Riitta-Leena; Lerkkanen, Marja-Kristiina; Nurmi, Jari-Erik

    2014-04-01

    In the longitudinal study presented here, we tested the theoretical assumption that children's task-focused behavior in learning situations mediates the associations between supportive interpersonal environments and academic performance. The sample consisted of 2,137 Finnish-speaking children. Data on supportive interpersonal environments (characterized by authoritative parenting, positive teacher affect toward the child, and peer acceptance) were gathered in Grade 1. The children's task-focused behavior was measured in Grades 2 and 3, and academic performance was measured in Grades 1 and 4. The results supported our assumption by showing that all three supportive environments were positively associated with children's subsequent academic performance via increased task-focused behavior in learning situations. These findings suggest that students' academic performance can be promoted by increasing the support they receive from peers, parents, and teachers because such increased support leads to better task focus in learning tasks.

  10. Policy to Foster Civility and Support a Healthy Academic Work Environment.

    Science.gov (United States)

    Clark, Cynthia M; Ritter, Katy

    2018-06-01

    Incivility in academic workplaces can have detrimental effects on individuals, teams, departments, and the campus community at large. Alternately, healthy academic workplaces generate heightened levels of employee satisfaction, engagement, and morale. This article describes the development and implementation of a comprehensive, legally defensible policy related to workplace civility and the establishment of a healthy academic work environment. A detailed policy exemplar is included to provide a structure for fostering a healthy academic work environment, a fair, consistent, confidential procedure for defining and addressing workplace incivility, a mechanism for reporting and subsequent investigation of uncivil acts if indicated, and ways to foster civility and respectful workplace behavior. The authors detail a step-by-step procedure and an incremental approach to address workplace incivility and reward policy adherence. [J Nurs Educ. 2018;57(6):325-331.]. Copyright 2018, SLACK Incorporated.

  11. Relationship of level of physical skills and academic achievemnts

    OpenAIRE

    Doubková, Karolína

    2010-01-01

    The thesis aims to investigate whether there is dependence between the level of physical skills and achievements in school. By means of test I will analyze the level of physical skills for pupils in lower multi-annual gymnasium. Based on the measured results I try to find and compare the level of physical skills and students academic achievemnt dependence in the first semester of that year. Subsequently I also detect, by using my pre-prepared questionnaire, the relationship of students to spo...

  12. A buoyancy-based screen of Drosophila larvae for fat-storage mutants reveals a role for Sir2 in coupling fat storage to nutrient availability.

    Directory of Open Access Journals (Sweden)

    Tânia Reis

    2010-11-01

    Full Text Available Obesity has a strong genetic component, but few of the genes that predispose to obesity are known. Genetic screens in invertebrates have the potential to identify genes and pathways that regulate the levels of stored fat, many of which are likely to be conserved in humans. To facilitate such screens, we have developed a simple buoyancy-based screening method for identifying mutant Drosophila larvae with increased levels of stored fat. Using this approach, we have identified 66 genes that when mutated increase organismal fat levels. Among these was a sirtuin family member, Sir2. Sirtuins regulate the storage and metabolism of carbohydrates and lipids by deacetylating key regulatory proteins. However, since mammalian sirtuins function in many tissues in different ways, it has been difficult to define their role in energy homeostasis accurately under normal feeding conditions. We show that knockdown of Sir2 in the larval fat body results in increased fat levels. Moreover, using genetic mosaics, we demonstrate that Sir2 restricts fat accumulation in individual cells of the fat body in a cell-autonomous manner. Consistent with this function, changes in the expression of metabolic enzymes in Sir2 mutants point to a shift away from catabolism. Surprisingly, although Sir2 is typically upregulated under conditions of starvation, Sir2 mutant larvae survive better than wild type under conditions of amino-acid starvation as long as sugars are provided. Our findings point to a Sir2-mediated pathway that activates a catabolic response to amino-acid starvation irrespective of the sugar content of the diet.

  13. Study of academic achievements using spatial analysis tools

    Science.gov (United States)

    González, C.; Velilla, C.; Sánchez-Girón, V.

    2012-04-01

    In the 2010/12 academic year the College of Agricultural Engineering of the Technical University of Madrid implemented three new degrees all of them adapted to the European Space for Higher Education. These degrees are namely: Graduate in Agricultural Engineering and Science, Graduate in Food Engineering and Graduate in Agro-Environmental Engineering. A total of 382 new incoming students were finally registered and a survey study was carried out with these students about their academic achievement with the aim of finding the level of dependence among the following variables: the final mark in their secondary studies, the option followed in the secondary studies (Art, Science and Technology, and Humanities and Social Sciences), the mark obtained in the entering examination to the university and in which of the two opportunities per year this examination takes place the latter mark was obtained. Similarly, another group of 77 students were evaluated independently to the former group. These students were those entering the College in the previous academic year (2009/10) and decided to change their curricula to the new ones. Subsequently, using the tools of spatial analysis of geographic information systems, we analyzed the possible relationship between the success or failure at school and the socioeconomic profile of new students in a grade. For this purpose every student was referenced assigning UTM coordinates to their postal addresses. Furthermore, all students' secondary schools were geographically coded considering their typology (public, private, and private subsidized) and fares. Each student was represented by its average geometric point in order to be correlated to their respective record. Following this procedure a map of the performance of each student could be drawn. This map can be used as a reference system, as it includes variables as the distance from the student home to the College, that can be used as a tool to calculate the probability of success or

  14. Visual Arts and Academic Achievement

    Science.gov (United States)

    Gibson, Marcia A.; Larson, Meredith A.

    2007-01-01

    The focus on academic performance testing in elementary schools has caused a decrease in student experience in the arts. Visual arts (drawing, painting, sculpture, and collage) have been minimized in elementary schools. Without exposure to the special avenues of cognitive development and personal expression nurtured by visual arts, students are…

  15. Recontextualising work into academic practices

    African Journals Online (AJOL)

    Erna Kinsey

    Globalisation and the related changes in social and economic practices have impacted strongly on teaching .... One aspect of work/academic curriculum interactions is that there is .... lecturers who were responsible for designing and teaching on the work ... were assessed on their ability to mimic the layout of a given news-.

  16. Organising for Effective Academic Entrepreneurship

    NARCIS (Netherlands)

    van der Sijde, Peter; McGowan, Pauric; van de Velde, Theodor; Youngleson, Jonathan

    2006-01-01

    The contribution has three parts. In the first part the concept of academic entrepreneurship is explained, defined and put into the context of the entrepreneurial university. In the second part four cases are described: - (1) The Nikos case at the University of Twente: In Nikos teaching, research

  17. Global Trends in Academic Governance

    Science.gov (United States)

    Cummings, William K.; Finkelstein, Martin

    2009-01-01

    Even before the current global economic crisis, discontent with the governance of higher education institutions was widespread among faculty in the United States and throughout the world. Drawing from the 2007 Changing Academic Profession (CAP) survey of faculty in seventeen countries, the authors examine faculty perceptions of the current state…

  18. Academic performance and behavioral patterns

    DEFF Research Database (Denmark)

    Kassarnig, Valentin; Mones, Enys; Bjerre-Nielsen, Andreas

    2018-01-01

    Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect...

  19. Academic Freedom: A Lawyer's Perspective

    Science.gov (United States)

    Davies, Mark

    2015-01-01

    Academic freedom is central to ideas of higher education, yet in the United Kingdom it is facing challenges from changing managerial approaches within some universities and changing governmental expectations. Universities are increasingly expected to focus upon knowledge which can be shown to have value and to exploit the results of academic…

  20. Managing Innovation in Academic Libraries.

    Science.gov (United States)

    Drake, Miriam A.

    1979-01-01

    Explores key issues related to innovation in academic libraries--performance gaps, incentives to innovate, nature of innovation, barriers and constraints, impact of innovation, and implementation of innovative strategies--and concludes that innovation requires a conducive climate, capital investment, and a leadership that is enthusiastic and…