Social-Emotional Learning Is Essential to Classroom Management

Science.gov (United States)

Jones, Stephanie M.; Bailey, Rebecca; Jacob, Robin

2014-01-01

Research tells us that children's social-emotional development can propel learning. A new program, SECURe, embeds that research into classroom management strategies that improve teaching and learning. Across all classrooms and grade levels, four principles of effective management are constant: Effective classroom management is based in…

The Dance of Elementary School Classroom Management

Science.gov (United States)

Powell, Pamela

2014-01-01

At times, classroom management and guidance elude even the most seasoned teachers. Yet, students need guidance and practice in self-regulatory skills to assist in the learning that occurs in classrooms. Teachers need both practical and research-based classroom management strategies that benefit the environment and help create a space conducive to…

Routines Are the Foundation of Classroom Management

Science.gov (United States)

Lester, Robin Rawlings; Allanson, Patricia Bolton; Notar, Charles E.

2017-01-01

Classroom management is the key to learning. Routines are the foundation of classroom management. Students require structure in their lives. Routines provide that in all of their life from the time they awake until the time they go to bed. Routines in a school and in the classroom provide the environment for learning to take place. The paper is…

Bringing Reality to Classroom Management in Teacher Education

Science.gov (United States)

Eisenman, Gordon; Edwards, Susan; Cushman, Carey Anne

2015-01-01

Learning how to manage a classroom effectively is a difficult task for preservice teachers. This is compounded by the lack of attention that classroom management receives in many teacher preparation programs and in the field of education in general. This article offers a rationale for the lack of attention to classroom management in teacher…

The Three Fs of Classroom Management

Science.gov (United States)

Daniels, Mark L.

2009-01-01

This article describes a cohesive theory of classroom management, developed by the author. This "three Fs" theory, predicated upon extant empiricism and scholarship vis-a-vis classroom management, was devised and implemented over several semesters within a field-based course at the University of Texas at Austin for preservice mathematics majors…

Why do Cross-Flow Turbines Stall?

Science.gov (United States)

Cavagnaro, Robert; Strom, Benjamin; Polagye, Brian

2015-11-01

Hydrokinetic turbines are prone to instability and stall near their peak operating points under torque control. Understanding the physics of turbine stall may help to mitigate this undesirable occurrence and improve the robustness of torque controllers. A laboratory-scale two-bladed cross-flow turbine operating at a chord-based Reynolds number ~ 3 ×104 is shown to stall at a critical tip-speed ratio. Experiments are conducting bringing the turbine to this critical speed in a recirculating current flume by increasing resistive torque and allowing the rotor to rapidly decelerate while monitoring inflow velocity, torque, and drag. The turbine stalls probabilistically with a distribution generated from hundreds of such events. A machine learning algorithm identifies stall events and indicates the effectiveness of available measurements or combinations of measurements as predictors. Bubble flow visualization and PIV are utilized to observe fluid conditions during stall events including the formation, separation, and advection of leading-edge vortices involved in the stall process.

Factors affecting stall use for different freestall bases.

Science.gov (United States)

Wagner-Storch, A M; Palmer, R W; Kammel, D W

2003-06-01

The objective of this study was to compare stall use (stall occupancy and cow position) by barn side for factors affecting stall use. A closed circuit television system recorded stall use four times per day for a 9-mo period starting May 9, 2001. Six factors were analyzed: stall base, distance to water, stall location within stall base section, stall location within barn, inside barn temperature, and length of time cows were exposed to stall bases. Two barn sides with different stocking densities were analyzed: low (66%), with cows milked by robotic milker; and high (100%), with cows milked 2X in parlor. Six stall base types were tested: two mattresses, a waterbed, a rubber mat, concrete, and sand (high side only). The base types were grouped 3 to 7 stalls/section and randomly placed in each row. Cows spent more time in mattress-based stalls, but the highest percentage lying was in sand-based stalls. The following significant stall occupancy percentages were found: sand had the highest percentage of cows lying on the high stocking density side (69%), followed by mattress type 1 (65%) > mattress type 2 (57%) > waterbed (45%) > rubber mat (33%) > concrete (23%). Mattress type 1 had the highest percentage stalls occupied (88%), followed by mattress type 2 (84%) > sand (79%) > soft rubber mat (65%) > waterbed (62%) > concrete (39%). On the low stocking rate side, mattress type 1 had the highest percentage cows lying (45%) and occupied (59.6%), followed by mattress type 2 > waterbed > soft rubber mat > concrete. Cow lying and stalls occupied percentages were highest for stalls 1) not at the end of a section, and 2) on the outside row, and varied by base type for time cows exposed to stalls and inside barn temperature. Lying and occupied percentages were different for different mattress types. The percentage of stalls with cows standing was higher for mat and mattress-based stalls. Results show mattress type 1 and sand to be superior and rubber mats and concrete inferior

Classroom Management in Foreign Language Education: An Exploratory Review

Directory of Open Access Journals (Sweden)

Diego Fernando Macías

2018-01-01

Full Text Available This review examines studies in the area of classroom management in foreign language education. It is organized into three large areas: The first area focuses on the distinctive characteristics of foreign language instruction that are more likely to impact classroom management in foreign language classes. The second area provides a description of classroom management issues that foreign language teachers usually encounter in their practice; and the third area centers on the different alternatives to reduce the negative impact of classroom management on foreign language classes. Conclusions suggest a need for more research particularly on the relationship between classroom management and aspects such as target language use and teaching methods.

A comparison of free-stall barns used by modernized Wisconsin dairies.

Science.gov (United States)

Bewley, J; Palmer, R W; Jackson-Smith, D B

2001-02-01

A primary objective of the Wisconsin Dairy Modernization Survey was to compare features of free-stall barns available to dairy producers. This study used data from a large random sample of expanding dairy farms to determine whether the theoretical benefits of particular free-stall configurations bear out under on-farm conditions. Comparisons were made among herds using free-stall barns as their primary housing for new versus remodeled facilities, barn design, bedding used, feed-delivery design, manure removal strategies, animal restraint, maternity areas, overcrowding, and cooling methods. Producers who made the transition from tie-stall housing to free-stall housing were satisfied with this decision. New free-stall barns provided a more desirable environment for the herds than remodeled free-stall barns, although initial investments were higher. When new free-stall barns were compared, herds with four-row barns had higher production, lower somatic cell count, and higher stocking rates than herds with six-row barns. Respondents were more satisfied with four- and six-row barns than with two- and three-row barns. Respondents felt sand provided some advantages for cow comfort, while satisfaction with bedding cost and manure handling was higher with mattresses. Dairy Herd Improvement data showed no difference in milk production or somatic cell count for producers who chose sand or mattress-based free stalls. Respondents were more satisfied with the use of drive-through feeding than other feed-delivery designs. Most producers chose to use tractor scrapers to remove manure; however, producers who used automated systems were more satisfied with manure management. Few differences were observed when comparing self-locking head gates to palpation rails. Overcrowding did not have any adverse affect on production or user satisfaction with feed intake or cow comfort. Using supplemental cooling appeared to facilitate higher production.

14 CFR 25.203 - Stall characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Stall characteristics. 25.203 Section 25.203 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Stalls § 25.203 Stall characteristics. (a) It must...

Classroom Profiling Training: Increasing Preservice Teachers' Confidence and Knowledge of Classroom Management Skills

Science.gov (United States)

Jackson, Cliff; Simoncini, Kym; Davidson, Mark

2013-01-01

Classroom management is a serious concern for beginning teachers including preservice teachers. The Queensland Department of Education, Training and Employment (DETE) has developed the Essential Skills for Classroom Management (ESCM), a system of positive and pro-active strategies for maintaining supportive learning environments. In addition, the…

Effects of three types of free-stall surfaces on preferences and stall usage by dairy cows.

Science.gov (United States)

Tucker, C B; Weary, D M; Fraser, D

2003-02-01

One important criterion in choosing appropriate housing systems for dairy cattle is that the freestall provides a comfortable surface for the cow. This paper describes two experiments testing the effects of commonly used lying surfaces on stall preference and stall usage by Holstein cows. In both experiments, 12 cows were housed individually in separate pens. Each pen contained three free stalls with a different surface: deep-bedded sawdust, deep-bedded sand, and a geotextile mattress covered with 2 to 3 cm of sawdust. The animals were restricted to each surface in turn, in a random order for either 2 (Experiment 1) or 3 d (Experiment 2). Both before and after this restriction phase, the animals were allowed access to all three surfaces, and preference was determined, based on lying times. Of the 12 cows used in Experiment 1, 10 preferred sawdust before and nine after the restriction phase. During the restriction phase, average lying times and number of lying events during the restriction phase were significantly lower for the sand-bedded stalls (P sand bedded stalls. In this experiment, about half the cows preferred sand and half sawdust, after the restriction phase. During the restriction phase of experiment, lying times and number of lying events were lower, and standing times were higher when the animals were restricted to the mattresses compared to either sand or sawdust (P < or = 0.05). These results indicate that (1) free stall surface can affect both stall preferences and stall usage, and (2) mattresses are less preferred.

Dairy Cows Produce Less Milk and Modify Their Behaviour during the Transition between Tie-Stall to Free-Stall

Science.gov (United States)

Broucek, Jan; Uhrincat, Michal; Mihina, Stefan; Soch, Miloslav; Mrekajova, Andrea; Hanus, Anton

2017-01-01

Simple Summary The purpose of this study was to evaluate the influence of moving cows from the barn with stanchion-stall housing to free-stall housing on their behaviour and production. Cows lay down up to ten hours after removing. The cows in their second lactation and open cows tended to lie sooner after removing than cows in their first lactation and pregnant cows. The times of total lying and rumination were increasing from the first day to the tenth day after removing. Cows produced 23.3% less milk at the first day following the transfer than at the last day prior to moving (23.76 ± 7.20 kg vs. 30.97 ± 7.26 kg, p cows achieved maximum production. The difference was found in milk losses due to the shift between cows in first and second lactation. Abstract Transfer of cattle to an unknown barn may result in a reduction in its welfare. Housing and management practices can result in signs of stress that include a long-term suppression of milk efficiency. The purpose of this study was to evaluate the influence of moving cows from the stanchion-stall housing to free-stall housing on their behaviour and production. The Holstein cows were moved into the new facility with free-stall housing from the old barn with stanchion-stall housing. Cows lay down up to ten hours (596.3 ± 282.7 min) after removing. The cows in their second lactation and open cows tended to lie sooner after removing than cows in their first lactation and pregnant cows. The times of total lying and rumination were increasing from the first day to the tenth day after removing (23.76 ± 7.20 kg vs. 30.97 ± 7.26 kg, p Cows produced 23.3% less milk at the first day following the transfer than at the last day prior to moving (p cows on the first and second lactation (p cows’ milk production. However, when the cows are moved to a better environment, they rapidly adapt to the change. PMID:28273810

Classroom Management and Teachers' Coping Strategies: Inside Classrooms in Australia, China and Israel

Science.gov (United States)

Romi, Shlomo; Lewis, Ramon; Roache, Joel

2013-01-01

This paper discusses the degree to which recently reported relationships between the classroom management techniques and coping styles of Australian teachers apply in two other national settings: China and Israel. Little is known about which teacher characteristics relate to their approach to classroom management, although researchers in Australia…

Classroom Management for Early Childhood Music Settings

Science.gov (United States)

Koops, Lisa Huisman

2018-01-01

Classroom management is a common concern for preservice teachers and can be a key to success for in-service teachers. In this article, I discuss six strategies for classroom management: design and lead engaging music activities, employ music-rich transitions, balance familiarity and novelty, plan for success, communicate clear expectations, and…

A Resource-Allocation Theory of Classroom Management.

Science.gov (United States)

McDonald, Frederick J.

A fresh approach to classroom management, which responds both to the present body of knowledge in this area and extends to beginning teachers a practical, flexible, and simple method of maintaining classroom control, is presented. Shortcomings of previous management theories (in particular, the Direct Instruction Model) are discussed, and the need…

Simulator Studies of the Deep Stall

Science.gov (United States)

White, Maurice D.; Cooper, George E.

1965-01-01

Simulator studies of the deep-stall problem encountered with modern airplanes are discussed. The results indicate that the basic deep-stall tendencies produced by aerodynamic characteristics are augmented by operational considerations. Because of control difficulties to be anticipated in the deep stall, it is desirable that adequate safeguards be provided against inadvertent penetrations.

The analysis on centrifugal compressor rotating stall

International Nuclear Information System (INIS)

Kim, Ji Hwan; Kim, Kwang Ho; Shin, You Hwan

2003-01-01

In the present study, the performance characteristics and the number of stall cell during rotating stall of a centrifugal air compressor were experimentally investigated. Rotating stall in the vaneless diffuser were investigated by measuring unsteady pressure fluctuations at several different diffuser radius using a high frequency pressure transducer. The number of stall cell and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly forced on the analysis for the stall cell number and its propagation speed unstable operating region of the compressor. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates. To obtain the visualize the existence rotating stall, auto-correlation function and the frequency spectra of the pressure fluctuations were measured at r/r2=1.52. When the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct of the compressor. And the flow coefficient is lower than 0.086, several stall cell groups of discrete frequencies are observed

The quest for stall-free dynamic lift

Science.gov (United States)

Tung, C.; Mcalister, K. W.; Carr, Lawrence W.; Duque, E.; Zinner, R.

1992-01-01

During the past decade, numerous major effects have addressed the question of how to control or alleviate dynamic stall effects on helicopter rotors, but little concrete evidence of any significant reduction of the adverse characteristics of the dynamic stall phenomenon has been demonstrated. Nevertheless, it is important to remember that the control of dynamic stall is an achievable goal. Experiments performed at the US Army Aeroflight-dynamics Directorate more than a decade ago demonstrated that dynamic stall is not an unavoidable penalty of high amplitude motion, and that airfoils can indeed operate dynamically at angles far above the static-stall angle without necessarily forming a stall vortex. These experiments, one of them featuring a slat that was designed from static airfoil considerations, showed that unsteadiness can be a very beneficial factor in the development of high-lift devices for helicopter rotors. The experience drawn from these early experiments is now being focused on a program for the alleviation of dynamic-stall effects on helicopter rotors. The purpose of this effort is to demonstrate that rotor stall can be controlled through an improved understanding of the unsteady effects on airfoil stall and to document the role of specific means that lead to stall alleviation in the three dimensional unsteady environment of helicopter rotors in forward flight. The first concept to be addressed in this program will be a slatted airfoil. A two dimensional unsteady Navier-Stokes code has been modified to compute the flow around a two-element airfoil.

Classroom management, student-teacher relationships and quality in education

DEFF Research Database (Denmark)

Christensen, Mette Vedsgaard

Knowledge about classroom management is crucial for both teachers’ and students’ well-being and educational success. Studies have indicated that teaching and learning cannot take place effectively in poorly managed classrooms (Jones & Jones, 2012; Marzano, Marzano & Pickering, 2003), and research...... classroom management strategies and teacher-student relations, and by adjusting and applying insights from theory in pedagogical practice, we have introduced new ways of managing learning environments....... unanimously concludes that the competence to establish and maintain good teacher-student relations is a central teacher competence (Nordenbo et al., 2008;Cornelius Whiite, 2007; Mitchell, 2008; Hattie, 2009).This paper presents the findings from recent research and development projects concerning classroom...

Coping Styles as Mediators of Teachers' Classroom Management Techniques

Science.gov (United States)

Lewis, Ramon; Roache, Joel; Romi, Shlomo

2011-01-01

This study reports the relationships between coping styles of Australian teachers and the classroom based classroom management techniques they use to cope with student misbehaviour. There is great interest internationally in improving educational systems by upgrading the quality of teachers' classroom management. However, the relationship between…

The Influence of Group Training in the Incredible Years Teacher Classroom Management Program on Preschool Teachers' Classroom Management Strategies

Science.gov (United States)

Carlson, John S.; Tiret, Holly B.; Bender, Stacy L.; Benson, Laurie

2011-01-01

This study examined changes in preschool teachers' perceptions of classroom management strategies following group training in the recently revised Incredible Years Teacher Classroom Management Program (C. Webster-Stratton, 2006). The authors used a pre/post follow-up design across 2 groups that each met for 8 sessions over an 8-10-week period for…

Developing a protocol for evaluating teachers' classroom management styles

OpenAIRE

Đigić, Gordana; Stojiljković, Snežana

2011-01-01

The paper first defines the concept of classroom management and highlights the key-elements and presuppositions of successful classroom management. Further follows a description of different styles based on views of Martin and Baldwin who stress three dimensions of classroom management: personality (the teacher's convictions about the student's personality and actions based on them), teaching (what the teacher does to initiate and maintain class activities) and discipline (the procedures the ...

Preparing Preservice Teachers for Inclusive Classrooms: Does Completing Coursework on Managing Challenging Behaviours Increase Their Classroom Management Sense of Efficacy?

Science.gov (United States)

O'Neill, Sue C.

2015-01-01

Preservice teacher education courses provide an opportunity for the development of knowledge, skills, and confidence in classroom and behaviour management. This study reports the change in classroom management sense of efficacy (CMSE) of a small cohort of Australian preservice primary teachers at 4 time points (precoursework, preprofessional…

An International Perspective on Classroom Management: What Should Prospective Teachers Learn?

Science.gov (United States)

Wubbels, Theo

2011-01-01

Drawing upon a review of relevant literature, this paper provides an overview of the treatment of classroom management in teacher education and teaching around the world. Six approaches to classroom management are distinguished: classroom management approaches that focus on external control of behaviour, on internal control, on classroom ecology,…

Effective Classroom Management Techniques for Secondary Schools

African Journals Online (AJOL)

Effective Classroom Management Techniques for Secondary Schools. ... engagement of students in activities, use of innovative instructional strategies by teachers, ... and teachers in their perception regarding the effects of teachers classroom ...

PROSPECTIVE EFL TEACHERS’ PERCEPTIONS OF CLASSROOM MANAGEMENT AND MISBEHAVIOUR

OpenAIRE

CABAROĞLU, Nese

2014-01-01

The purpose of this small scale study was to determine pre-service teachers’ perceptions of classroom management, misbehaviour, and of their own ability to teach in relation to classroom management. Semi-structured interviews were conducted before and after teaching practice with eleven EFL (English as a Foreign Language) student teachers. Findings suggest that they have a narrow conception of classroom management, often focusing one aspect of it. Additionally, their confidence to teach seem ...

Effective Classroom Management

Science.gov (United States)

Mansor, Azlin Norhaini; Eng, Wong Kim; Rasul, Mohamad Sattar; Hamzah, Mohd Izham Mohd; Hamid, Aida Hanim A.

2012-01-01

This paper attempts to explore and identify the characteristics of an effective teacher who teaches English as a second language to 10 year old students from different ethnics, various social economic background and multi-level language ability, at a private primary school in Malaysia. The study focused on classroom management using a case study…

Exploring Teachers' Knowledge of Classroom Management and Control

Science.gov (United States)

Ayebo, Abraham; Assuah, Charles

2017-01-01

Purpose: This paper presents the results of a study that sought to determine teacher conceptions of classroom management and control. The study explored classroom management knowledge of participants, and how the knowledge was gained. It also investigated the extent to which participants held various conceptions, including rule-based, dominance…

Professional Vision of Classroom Management and Learning Support in Science Classrooms--Does Professional Vision Differ across General and Content-Specific Classroom Interactions?

Science.gov (United States)

Steffensky, Mirjam; Gold, Bernadette; Holdynski, Manfred; Möller, Kornelia

2015-01-01

The present study investigates the internal structure of professional vision of in-service teachers and student teachers with respect to classroom management and learning support in primary science lessons. Classroom management (including monitoring, managing momentum, and rules and routines) and learning support (including cognitive activation…

Geography Teachers' Attitudes and Beliefs Regarding Classroom Management

Science.gov (United States)

Dikmenli, Yurdal; Çifçi, Taner

2016-01-01

This study scrutinizes geography teachers' attitude and belief levels regarding classroom management. As a matter of fact, classroom management is one of the prominent areas emphasized by all educators. Descriptive correlational survey model was used in the study. Study group includes 58 geography teachers working in Sivas province during the…

Mistake management in a foreign language classroom

OpenAIRE

Volkova, Ekaterina

2012-01-01

The aim of the thesis is to design general recomendations on mistake management in a foreign language classroom which would meet both teachers' and learners' requirements and methods of mistake management in a foreign language classroom which would contribute to development of learners' communicative competence. The following methods were used in the research: analysis of literature on pedagogy, psychology and methodology of foreign language teaching, interview, questionnaire and observation....

Rotating stall simulation for axial and centrifugal compressors

Science.gov (United States)

Halawa, Taher; Gadala, Mohamed S.

2017-05-01

This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

16 CFR 1505.50 - Stalled motor testing.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Stalled motor testing. 1505.50 Section 1505... USE BY CHILDREN Policies and Interpretations § 1505.50 Stalled motor testing. (a) § 1505.6(e)(4)(ii) requires that a motor-operated toy be tested with the motor stalled if the construction of the toy is such...

Classroom Management and Learning.

Science.gov (United States)

Brophy, Jere E.

1982-01-01

Survey results show that planning and constant vigilance are the price of effective teaching. Effective classroom management involves awareness, good organizational skills, preparation, letting students know what is expected of them and following through, and the ability to diagnose student problems. (CT)

The Relevance of the Dynamic Stall Effect for Transient

DEFF Research Database (Denmark)

Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

2005-01-01

This article describes a methodology to quantify the influence of dynamic stall on transient fault operations of active-stall turbines. The model of the dynamic stall effect is introduced briefly. The behaviour of the dynamic stall model during a transient fault operation is described mathematica...

Bacillus cereus in free-stall bedding.

Science.gov (United States)

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

beds had increased about 2 log units and were as high as they were before bed replacement. Therefore, free-stall management could, to a limited extent, reduce the content of B. cereus spores in the beds by daily bedding and entire bed replacement.

Flexible Grouping as a Means for Classroom Management in a Heterogeneous Classroom

Science.gov (United States)

Rytivaara, Anna

2011-01-01

This article concerns issues of classroom management in heterogeneous classrooms. Although research in the field of learning styles has yielded mixed results, there is a call for information about how they could be used to individualize instruction, especially in primary schools. This article is part of an ethnographic study aiming to examine…

Teacher Self-Efficacy and Classroom Management Styles in Jordanian Schools

Science.gov (United States)

Abu-Tineh, Abdullah M.; Khasawneh, Samar A.; Khalaileh, Huda A.

2011-01-01

Two main purposes guided this study. The first was to identify the degree to which Jordanian teachers practise classroom management styles in their classrooms and their level of teacher self-efficacy. The second purpose was to explore the relationships between classroom management styles and teacher self-efficacy. This study is quantitative in…

Biomimetic Wind Turbine Design with Lift Enhancing Periodic Stall

NARCIS (Netherlands)

Stamhuis, Eize Jan

2017-01-01

A wind turbine includes a rotor; a blade; and a periodic stall system. The periodic stall system selectively moves at least part of the blade in an oscillating motion whereby an angle of incidence continuously varies to invoke periodic stall. The periodic stall system can move the entire blade or

Teachers' Conflict Management Styles: The Role of Attachment Styles and Classroom Management Efficacy

Science.gov (United States)

Morris-Rothschild, Britta K.; Brassard, Marla R.

2006-01-01

Constructive conflict management strategies are important in maintaining a positive classroom environment yet little is known about interpersonal or school variables associated with teachers' use of such strategies with students. Teachers high in self-reported classroom management efficacy (CMEFF) and security of attachment (low on avoidance,…

Close-loop Dynamic Stall Control on a Pitching Airfoil

Science.gov (United States)

Giles, Ian; Corke, Thomas

2017-11-01

A closed-loop control scheme utilizing a plasma actuator to control dynamic stall is presented. The plasma actuator is located at the leading-edge of a pitching airfoil. It initially pulses at an unsteady frequency that perturbs the boundary layer flow over the suction surface of the airfoil. As the airfoil approaches and enters stall, the amplification of the unsteady disturbance is detected by an onboard pressure sensor also located near the leading edge. Once detected, the actuator is switched to a higher voltage control state that in static airfoil experiments would reattach the flow. The threshold level of the detection is a parameter in the control scheme. Three stall regimes were examined: light, medium, and deep stall, that were defined by their stall penetration angles. The results showed that in general, the closed-loop control scheme was effective at controlling dynamic stall. The cycle-integrated lift improved in all cases, and increased by as much as 15% at the lowest stall penetration angle. As important, the cycle-integrated aerodynamic damping coefficient also increased in all cases, and was made to be positive at the light stall regime where it traditionally is negative. The latter is important in applications where negative damping can lead to stall flutter.

Evaluation of Teachers' Opinions About Effective Classroom Management Practices

Directory of Open Access Journals (Sweden)

Soner DOĞAN

2014-12-01

Full Text Available The aim of this study is to evaluate teacher behaviour in creating an effective classroom management process with regard to the views of the teachers working in primary and secondary schools. This is a qualitative study in which the case study design was used. The related literature was scanned and 9 open-ended questions were prepared. These questions that based on maximum variation sampling method were posed to 18 teachers. The data were collected by interview forms and were examined by descriptive and content analysis methods. According to the findings obtained, teachers have stated that pre-determination of classroom rules, asking for students' advices, lecturing in a planned manner, planned teaching, various methods, communication skills, time management, being a model and transitions between activities affect the process of classroom management positively; while punishment affects it in a partly positive way and the differences among the discipline perceptions affect the classroom management negatively

Stalling Tropical Cyclones over the Atlantic Basin

Science.gov (United States)

Nielsen-Gammon, J. W.; Emanuel, K.

2017-12-01

Hurricane Harvey produced massive amounts of rain over southeast Texas and southwest Louisiana. Average storm total rainfall amounts over a 10,000 square mile (26,000 square km) area exceeded 30 inches (750 mm). An important aspect of the storm that contributed to the large rainfall totals was its unusual motion. The storm stalled shortly after making landfall, then moved back offshore before once again making landfall five days later. This storm motion permitted heavy rainfall to occur in the same general area for an extended period of time. The unusual nature of this event motivates an investigation into the characteristics and potential climate change influences on stalled tropical cyclones in the Atlantic basin using the HURDAT 2 storm track database for 1866-2016 and downscaled tropical cyclones driven by simulations of present and future climate. The motion of cyclones is quantified as the size of a circle circumscribing all storm locations during a given length of time. For a three-day period, Harvey remained inside a circle with a radius of 123 km. This ranks within the top 0.6% of slowest-moving historical storm instances. Among the 2% of slowest-moving storm instances prior to Harvey, only 13 involved storms that stalled near the continental United States coast, where they may have produced substantial rainfall onshore while tapping into marine moisture. Only two such storms stalled in the month of September, in contrast to 20 September stalls out of the 36 storms that stalled over the nearby open Atlantic. Just four of the stalled coastal storms were hurricanes, implying a return frequency for such storms of much less than once per decade. The synoptic setting of these storms is examined for common features, and historical and projected trends in occurrences of stalled storms near the coast and farther offshore are investigated.

Comprehending Elementary School Teachers' Classroom Management Approaches

Science.gov (United States)

Sahin, Ali E.

2015-01-01

This study intends to determine elementary school teachers' degree of classroom control, which constitutes the consistency in their classroom management and discipline-related behaviour. The major research question was as follows: Is the control approach adopted by teachers related to certain variables (gender, age, subject area, experience)? The…

Teacher Classroom Management Practices: Effects on Disruptive or Aggressive Student Behavior

Science.gov (United States)

Oliver, Regina M.; Wehby, Joseph H.; Reschly, Daniel J.

2011-01-01

Despite the large research base grounded in behavioral theory for strategies to increase appropriate behavior and prevent or decrease inappropriate behavior in the classroom, a systematic review of multi-component universal classroom management research is necessary to establish the effects of teachers' universal classroom management approaches.…

The Development of Novice Teachers' Culturally Responsive Classroom Management Practice

Science.gov (United States)

Patish, Yelena

2016-01-01

While extensive research has been conducted on classroom management little research exists on culturally responsive classroom management. The primary purpose of this qualitative study was to examine how four novice teachers developed their culturally responsive management practice (CRCM) to better meet the needs of their students. My analysis was…

Dynamic Stall Control Using Plasma Actuators

Science.gov (United States)

Webb, Nathan; Singhal, Achal; Castaneda, David; Samimy, Mo

2017-11-01

Dynamic stall occurs in many applications, including sharp maneuvers of fixed wing aircraft, wind turbines, and rotorcraft and produces large unsteady aerodynamic loads that can lead to flutter and mechanical failure. This work uses flow control to reduce the unsteady loads by excitation of instabilities in the shear layer over the separated region using nanosecond pulse driven dielectric barrier discharge (NS-DBD) plasma actuators. These actuators have been shown to effectively delay or mitigate static stall. A wide range of flow parameters were explored in the current work: Reynolds number (Re = 167,000 to 500,000), reduced frequency (k = 0.025 to 0.075), and excitation Strouhal number (Ste = 0 to 10). Based on the results, three major conclusions were drawn: (a) Low Strouhal number excitation (Ste <0.5) results in oscillatory aerodynamic loads in the stalled stage of dynamic stall; (b) All excitation resulted in earlier flow reattachment; and (c) Excitation at progressively higher Ste weakened and eventually eliminated the dynamic stall vortex (DSV), thereby dramatically reducing the unsteady loading. The decrease in the strength of the DSV is achieved by the formation of shear layer coherent structures that bleed the leading-edge vorticity prior to the ejection of the DSV.

Observations of dynamic stall on Darrieus wind turbine blades

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, N.; Shibuya, S. [Department of Mechanical and Production Engineering, Niigata University, 8050 Ikarashi 2, 950-2181 Niigata (Japan)

2001-02-01

Flow field around a Darrieus wind turbine blade in dynamic stall is studied by flow visualization and particle image velocimetry (PIV) measurement in stationary and rotating frames of reference. The experiment is carried out using the small-scale Darrieus wind turbine in a water tunnel. The unsteady nature of the dynamic stall observed by the flow visualization is quantitatively reproduced in the instantaneous velocity distributions by PIV measurement, which describes the successive shedding of two pairs of stall vortices from the blade moving upstream. The mechanism of dynamic stall is due to the successive generation of separation on the inner surface of the blade followed by the formation of roll-up vortices from the outer surface. Although the qualitative nature of the dynamic stall is independent of the tip-speed ratios, the blade angle for stall appearance and the growth rate of the stall vortices are influenced by the change in tip-speed ratios.

An Interpersonal Approach to Classroom Management: Strategies for Improving Student Engagement. Classroom Insights from Educational Psychology

Science.gov (United States)

Davis, Heather A.; Summers, Jessica J.; Miller, Lauren M.

2012-01-01

Like having a hidden camera in other teachers' classrooms, An Interpersonal Approach to Classroom Management engages you from the start by contrasting how two teachers respond differently to common situations. The authors expertly bridge the gap between educational psychology and peer and student-teacher management from the perspectives of student…

A Model for Online Support in Classroom Management: Perceptions of Beginning Teachers

Science.gov (United States)

Baker, Credence; Gentry, James; Larmer, William

2016-01-01

Classroom management is a challenge for beginning teachers. To address this challenge, a model to provide support for beginning teachers was developed, consisting of a one-day workshop on classroom management, followed with online support extending over eight weeks. Specific classroom management strategies included (a) developing a foundation…

Simulation model of an active stall wind turbine controller

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Hansen, A.D.; Soerensen, P. [Risoe National Lab., Wind Energy Dept., Rosilde (Denmark); Blaabjerg, F. [Aalborg Univ., Inst. of Energy Technology (Denmark)

2004-07-01

This paper describes an active stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated on the basis of simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut doven wind speed. Due to its parametric implementation it is general i.e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (au)

Classroom Management in Foreign Language Education: An Exploratory Review

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Macías, Diego Fernando

2018-01-01

This review examines studies in the area of classroom management in foreign language education. It is organized into three large areas: The first area focuses on the distinctive characteristics of foreign language instruction that are more likely to impact classroom management in foreign language classes. The second area provides a description of…

The Relationship between Classroom Management and Graduate Students' Academic Procrastination

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naser nastiezaie

2017-06-01

Full Text Available AWT IMAGE Background and Objective: Academic procrastination is one of the common phenomena among students that can affect classroom management in different ways.. This study aimed to investigate the relationship between classroom management and academic procrastination in graduate students at University of Sistan and Baluchistan. Materials and Methods: This study is descriptive-correlational (regression. The study population was all graduate students of the University of Sistan and Baluchestan in the first half of the academic year 2015-2016. By using stratified convenience sampling method, 328 students were selected and studied through applying two questionnaires of class management that were made by researchers and Savari’s academic procrastination questionnaire. To analyze the data, Pearson correlation coefficient, simultaneous multiple regression analysis, and SPSS21 software were used. Results: Mean scores were as follows: designing and organizing (3.49±0.452, leadership (3.58±0.422, monitoring and control (3.42±0.48, evaluation (2.92±0.708, classroom management (3.35±0.346, academic procrastination (2.05±1.169. Correlation coefficients of designing and organizing, leadership, monitoring and control, evaluation, classroom management with academic procrastination were -0.3,-0.391,-0.414,-0.544 and -0.637 (p<0.01 respectively. Based on the results of regression analysis, class management components showed 41.5 of the variance of academic procrastination (p<0.01. Conclusion The faculty can effectively and efficiently manage their classroom by improving designing and organizing, leadership, monitoring and control, and evaluation skills. This may result in reduction of students' academic procrastination. Keywords: Classroom management, Designing and organizing, Leadership, Monitoring and control, Evaluation, Academic procrastination.

Classroom Management and Students' Self-Esteem: Creating Positive Classrooms

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Demirdag, Seyithan

2015-01-01

Middle school students experience substantial changes in their emotion and cognition while they grow. They have mixed feelings, which may negatively affect their motivation, self-esteem, and academic success due to different classroom management strategies of their teachers. There is available research about motivation of middle school students…

Classroom Management: Seating Solutions [and] Hooray for Volunteers.

Science.gov (United States)

Novelli, Joan; Edgar, Susan

1997-01-01

Two articles present suggestions for enhancing classroom management in creative ways. The first article describes how to use flexible seating arrangements to encourage cooperation, friendship, and community. The second article discusses how to encourage and work with classroom volunteers from the community. (SM)

The relationship between EFL teachers’ beliefs and actual practices of classroom management

OpenAIRE

Mohammad Aliakbari; Mohsen Heidarzadi

2015-01-01

This study aimed at analyzing Iranian EFL teachers’ beliefs toward classroom management and the relationship between teachers’ beliefs and their actual practices of classroom management in regard with individual variables such as gender, education degree, and teaching experience. The data were collected using a behavior and instructional management scale inventory and direct class observation through a researcher made classroom management observation checklist. The findings showed that EFL te...

Revolving Classroom Door: Management Strategies To Eliminate the Quick Spin.

Science.gov (United States)

Rancifer, Jesse L.

This paper presents classroom management practices that can be used to avoid the "revolving classroom door." In the revolving classroom door, misbehaving students are sent to the principal, and eventually returned to the classroom with no gains in student behavior or opportunity for learning. The paper begins by discussing the meaning of classroom…

Cow comfort in tie-stalls: increased depth of shavings or straw bedding increases lying time.

Science.gov (United States)

Tucker, C B; Weary, D M; von Keyserlingk, M A G; Beauchemin, K A

2009-06-01

Over half of US dairy operations use tie-stalls, but these farming systems have received relatively little research attention in terms of stall design and management. The current study tested the effects of the amount of 2 bedding materials, straw and shavings, on dairy cattle lying behavior. The effects of 4 levels of shavings, 3, 9, 15, and 24 kg/stall (experiment 1, n = 12), and high and low levels of straw in 2 separate experiments: 1, 3, 5, and 7 kg/stall (experiment 2, n = 12) and 0.5, 1, 2, and 3 kg/stall (experiment 3, n = 12) were assessed. Treatments were compared using a crossover design with lactating cows housed in tie-stalls fitted with mattresses. Treatments were applied for 1 wk. Total lying time, number of lying bouts, and the length of each lying bout was recorded with data loggers. In experiment 1, cows spent 3 min more lying down for each additional kilogram of shavings (11.0, 11.7, 11.6, and 12.1 +/- 0.24 h/d for 3, 9, 15, and 24 kg/stall shavings, respectively). In experiment 2, cows increased lying time by 12 min for every additional kilogram of straw (11.2, 12.0, 11.8, and 12.4 +/- 0.24 h/d for 1, 3, 5, and 7 kg/stall of straw, respectively). There were no differences in lying behavior among the lower levels of straw tested in experiment 3 (11.7 +/- 0.32 h/d). These results indicated that additional bedding above a scant amount improves cow comfort, as measured by lying time, likely because a well-bedded surface is more compressible.

Classroom Management through the Eyes of Elementary Teachers in Turkey: A Phenomenological Study

Science.gov (United States)

Akin, Sibel; Yildirim, Ali; Goodwin, A. Lin

2016-01-01

This study aims to explore Turkish elementary teachers' (1) perceptions of classroom management, (2) classroom management problems they experience, (3) factors causing these problems, and (4) their classroom management practices. The study employed phenomenological research design in the qualitative tradition. The participants included 15…

Compressible dynamic stall control using high momentum microjets

Science.gov (United States)

Beahan, James J.; Shih, Chiang; Krothapalli, Anjaneyulu; Kumar, Rajan; Chandrasekhara, Muguru S.

2014-09-01

Control of the dynamic stall process of a NACA 0015 airfoil undergoing periodic pitching motion is investigated experimentally at the NASA Ames compressible dynamic stall facility. Multiple microjet nozzles distributed uniformly in the first 12 % chord from the airfoil's leading edge are used for the dynamic stall control. Point diffraction interferometry technique is used to characterize the control effectiveness, both qualitatively and quantitatively. The microjet control has been found to be very effective in suppressing both the emergence of the dynamic stall vortex and the associated massive flow separation at the entire operating range of angles of attack. At the high Mach number ( M = 0.4), the use of microjets appears to eliminate the shock structures that are responsible for triggering the shock-induced separation, establishing the fact that the use of microjets is effective in controlling dynamic stall with a strong compressibility effect. In general, microjet control has an overall positive effect in terms of maintaining leading edge suction pressure and preventing flow separation.

The Dynamics of SecM-Induced Translational Stalling

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Albert Tsai

2014-06-01

Full Text Available SecM is an E. coli secretion monitor capable of stalling translation on the prokaryotic ribosome without cofactors. Biochemical and structural studies have demonstrated that the SecM nascent chain interacts with the 50S subunit exit tunnel to inhibit peptide bond formation. However, the timescales and pathways of stalling on an mRNA remain undefined. To provide a dynamic mechanism for stalling, we directly tracked the dynamics of elongation on ribosomes translating the SecM stall sequence (FSTPVWISQAQGIRAGP using single-molecule fluorescence techniques. Within 1 min, three peptide-ribosome interactions work cooperatively over the last five codons of the SecM sequence, leading to severely impaired elongation rates beginning from the terminal proline and lasting four codons. Our results suggest that stalling is tightly linked to the dynamics of elongation and underscore the roles that the exit tunnel and nascent chain play in controlling fundamental steps in translation.

Classroom Management Affects Literacy Development of Students with Emotional and Behavioral Disorders

Science.gov (United States)

Garwood, Justin D.; Vernon-Feagans, Lynne

2017-01-01

Many children with behavior problems perform poorly academically and can disrupt regular classroom instruction. Although good classroom management strategies can benefit children with behavior problems, it is not clear whether these students need consistently good classroom management across the early elementary school years to improve their…

A Study on Teacher Candidates' Competencies in Classroom Management

Science.gov (United States)

Selçuk, Gülenaz; Kadi, Aysegül; Yildirim, Remzi; Çelebi, Nurhayat

2017-01-01

The objective of this paper is to examine competencies in classroom management of teacher candidates. Research design was determined as pre-experimental research design. Research was conducted with 388 teacher candidates. In this research, these were found; Attitudes of students about competencies in classroom management differ according to…

Student Teachers' Management Practices in Elementary Classrooms: A Qualitative Study

Science.gov (United States)

Hildenbrand, Susan M.; Arndt, Katrina

2016-01-01

This qualitative study of four student teachers completing certification in elementary and special education investigated the classroom management practices of the student teachers. This is an important area of study because management practices are essential for an effective classroom, and student teachers often lack confidence and skill in the…

Classroom as a social community and its management

OpenAIRE

Kovač, Nina

2016-01-01

The aim of this master′s thesis is to present classroom as a social community, focusing on teacher’s work. In the theoretical part, the thesis describes the history of schooling in Slovenian geographical area and defines concepts such as group, teacher, student and classroom. The most typical and commonly used classroom management styles are also presented. Data for the qualitative research are obtained from three class teachers who voluntarily participate in the research. Each teacher...

Analysing Mentoring Dialogues for Developing a Preservice Teacher's Classroom Management Practices

Science.gov (United States)

Sempowicz, Tracey; Hudson, Peter

2011-01-01

A key concern for preservice teachers is classroom management, including student behaviour management, which also has been a factor associated with teachers leaving the profession within the first five years. This study investigates the mentoring practices used to guide the mentee's classroom management. Using multiple data sources (e.g., lesson…

A numerical strategy for modelling rotating stall in core compressors

Science.gov (United States)

Vahdati, M.

2007-03-01

The paper will focus on one specific core-compressor instability, rotating stall, because of the pressing industrial need to improve current design methods. The determination of the blade response during rotating stall is a difficult problem for which there is no reliable procedure. During rotating stall, the blades encounter the stall cells and the excitation depends on the number, size, exact shape and rotational speed of these cells. The long-term aim is to minimize the forced response due to rotating stall excitation by avoiding potential matches between the vibration modes and the rotating stall pattern characteristics. Accurate numerical simulations of core-compressor rotating stall phenomena require the modelling of a large number of bladerows using grids containing several tens of millions of points. The time-accurate unsteady-flow computations may need to be run for several engine revolutions for rotating stall to get initiated and many more before it is fully developed. The difficulty in rotating stall initiation arises from a lack of representation of the triggering disturbances which are inherently present in aeroengines. Since the numerical model represents a symmetric assembly, the only random mechanism for rotating stall initiation is provided by numerical round-off errors. In this work, rotating stall is initiated by introducing a small amount of geometric mistuning to the rotor blades. Another major obstacle in modelling flows near stall is the specification of appropriate upstream and downstream boundary conditions. Obtaining reliable boundary conditions for such flows can be very difficult. In the present study, the low-pressure compression (LPC) domain is placed upstream of the core compressor. With such an approach, only far field atmospheric boundary conditions are specified which are obtained from aircraft speed and altitude. A chocked variable-area nozzle, placed after the last compressor bladerow in the model, is used to impose boundary

Dynamic Stall Characteristics of Drooped Leading Edge Airfoils

Science.gov (United States)

Sankar, Lakshmi N.; Sahin, Mehmet; Gopal, Naveen

2000-01-01

Helicopters in high-speed forward flight usually experience large regions of dynamic stall over the retreating side of the rotor disk. The rapid variations in the lift and pitching moments associated with the stall process can result in vibratory loads, and can cause fatigue and failure of pitch links. In some instances, the large time lag between the aerodynamic forces and the blade motion can trigger stall flutter. A number of techniques for the alleviation of dynamic stall have been proposed and studied by researchers. Passive and active control techniques have both been explored. Passive techniques include the use of high solidity rotors that reduce the lift coefficients of individual blades, leading edge slots and leading edge slats. Active control techniques include steady and unsteady blowing, and dynamically deformable leading edge (DDLE) airfoils. Considerable amount of experimental and numerical data has been collected on the effectiveness of these concepts. One concept that has not received as much attention is the drooped-leading edge airfoil idea. It has been observed in wind tunnel studies and flight tests that drooped leading edge airfoils can have a milder dynamic stall, with a significantly milder load hysteresis. Drooped leading edge airfoils may not, however, be suitable at other conditions, e.g. in hover, or in transonic flow. Work needs to be done on the analysis and design of drooped leading edge airfoils for efficient operation in a variety of flight regimes (hover, dynamic stall, and transonic flow). One concept that is worthy of investigation is the dynamically drooping airfoil, where the leading edge shape is changed roughly once-per-rev to mitigate the dynamic stall.

The relationship between EFL teachers’ beliefs and actual practices of classroom management

Directory of Open Access Journals (Sweden)

Mohammad Aliakbari

2015-12-01

Full Text Available This study aimed at analyzing Iranian EFL teachers’ beliefs toward classroom management and the relationship between teachers’ beliefs and their actual practices of classroom management in regard with individual variables such as gender, education degree, and teaching experience. The data were collected using a behavior and instructional management scale inventory and direct class observation through a researcher made classroom management observation checklist. The findings showed that EFL teachers favored interactionalist orientation on behavior and instructional management dimensions. Findings also indicated that male teachers were not significantly different from females in terms of the relationship between their beliefs and actual practices. However, there was a significant relationship between teachers’ beliefs and their actual practices of classroom management among less experienced teachers. It was further found that increase in teachers’ educational level led to decrease in discrepancy between their beliefs and actual practices.

From Discipline to Dynamic Pedagogy: A Re-Conceptualization of Classroom Management

Science.gov (United States)

Davis, Jonathan Ryan

2017-01-01

The purpose of this article is to re-conceptualize the definition of classroom management, moving away from its traditional definition rooted in discipline and control toward a definition that focuses on the creation of a positive learning environment. Integrating innovative, culturally responsive classroom management theories, frameworks, and…

Social Skills, Problem Behaviors and Classroom Management in Inclusive Preschool Settings

Science.gov (United States)

Karakaya, Esra G.; Tufan, Mumin

2018-01-01

This study aimed to determine preschool teachers' classroom management skills and investigate the relationships between teachers' classroom management skills and inclusion students' social skills and problem behaviors. Relational screening model was used as the research method. Study group consisted of 42 pre-school teachers working in Kocaeli…

Nonverbal Cues: The Key to Classroom Management.

Science.gov (United States)

Petrie, Garth; Lindauer, Patricia; Bennett, Brenda; Gibson, Sherri

1998-01-01

Principals should familiarize teachers with the benefits of nonverbal procedures for classroom management and discipline enforcement. A behavior-management checklist of nonverbal techniques (eye contact, touching, smiling, and frowning) can be used in a series of short visits. At least 75% of control techniques should be nonverbal. Relying on…

How an Active Learning Classroom Transformed IT Executive Management

Science.gov (United States)

Connolly, Amy; Lampe, Michael

2016-01-01

This article describes how our university built a unique classroom environment specifically for active learning. This classroom changed students' experience in the undergraduate executive information technology (IT) management class. Every college graduate should learn to think critically, solve problems, and communicate solutions, but 90% of…

Prediction of induced vibrations in stall

Energy Technology Data Exchange (ETDEWEB)

Thirstrup Petersen, J; Thomsen, K; Aagaard Madsen, H [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

1999-03-01

The main results from recent research in stall induced vibrations are presented. The focus is on the edgewise blade vibrations, which during the last decade have turned out to be a potential threat against the stable operation of stall regulated wind turbines and a fact, which must be dealt with by the designer. The basic physical explanation for the phenomenon and examples of design precaution, which can be taken, are presented. (au)

Flow and Noise Characteristics of Centrifugal Fan under Different Stall Conditions

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-01-01

Full Text Available An implicit, time-accurate 3D Reynolds-averaged Navier-Stokes (RANS solver is used to simulate the rotating stall phenomenon in a centrifugal fan. The goal of the present work is to shed light on the flow field and particularly the aerodynamic noise at different stall conditions. Aerodynamic characteristics, frequency domain characteristics, and the contours of sound power level under two different stall conditions are discussed in this paper. The results show that, with the decrease of valve opening, the amplitude of full pressure and flow fluctuations tends to be larger and the stall frequency remains the same. The flow field analysis indicates that the area occupied by stall cells expands with the decrease of flow rate. The noise calculation based on the simulation underlines the role of vortex noise after the occurrence of rotating stall, showing that the high noise area rotates along with the stall cell in the circumferential direction.

Simulation of Entropy Generation under Stall Conditions in a Centrifugal Fan

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-06-01

Full Text Available Rotating stalls are generally the first instability met in turbomachinery, before surges. This 3D phenomenon is characterized by one or more stalled flow cells which rotate at a fraction of the impeller speed. The goal of the present work is to shed some light on the entropy generation in a centrifugal fan under rotating stall conditions. A numerical simulation of entropy generation is carried out with the ANSYS Fluent software which solves the Navier-Stokes equations and user defined function (UDF. The entropy generation characteristics in the centrifugal fan for five typical conditions are presented and discussed, involving the design condition, conditions on occurrence and development of stall inception, the rotating stall conditions with two throttle coefficients. The results show that the entropy generation increases after the occurrence of stall inception. The high entropy generation areas move along the circumferential and axial directions, and finally merge into one stall cell. The entropy generation rate during circumferential propagation of the stall cell is also discussed, showing that the entropy generation history is similar to sine curves in impeller and volute, and the volute tongue has a great influence on entropy generation in the centrifugal fan.

"This Has to Be Family": Humanizing Classroom Management in Urban Schools

Science.gov (United States)

Ullucci, Kerri

2009-01-01

Classroom management in urban schools is frequently steeped in mythology. Students are seen as difficult and disrespectful, needing highly structured discipline policies in order to function. However, a different reality exists. This study looks at the way well-respected teachers in urban schools utilize their classroom space, manage their…

Teaching the Social Curriculum: Classroom Management as Behavioral Instruction

Science.gov (United States)

Skiba, Russ; Ormiston, Heather; Martinez, Sylvia; Cummings, Jack

2016-01-01

Psychological science has identified positive classroom management and climate building strategies as a key element in developing and maintaining effective learning environments. In this article, we review the literature that has identified effective strategies that build classroom climates to maximize student learning and minimize disruption. In…

Economic evaluation of stall stocking density of lactating dairy cows

NARCIS (Netherlands)

Vries, De Albert; Dechassa, Hailegziabher; Hogeveen, Henk

2016-01-01

An increase in stall stocking density (SSD), as measured by the number of lactating cows per stall in a freestall barn, reduces cow performance, such as milk yield and fertility, but may increase farm profitability. Our objectives were to calculate effects of varying SSD on profit per stall for a

Simulation model of an active-stall fixed-speed wind turbine controller

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Hansen, A.D.; Sorensen, P.; Blaabjerg, F.

2004-07-01

This paper describes an active-stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated by simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut down wind speed. Due to its parametric implementation it is general i. e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (author)

A CFD Database for Airfoils and Wings at Post-Stall Angles of Attack

Science.gov (United States)

Petrilli, Justin; Paul, Ryan; Gopalarathnam, Ashok; Frink, Neal T.

2013-01-01

This paper presents selected results from an ongoing effort to develop an aerodynamic database from Reynolds-Averaged Navier-Stokes (RANS) computational analysis of airfoils and wings at stall and post-stall angles of attack. The data obtained from this effort will be used for validation and refinement of a low-order post-stall prediction method developed at NCSU, and to fill existing gaps in high angle of attack data in the literature. Such data could have potential applications in post-stall flight dynamics, helicopter aerodynamics and wind turbine aerodynamics. An overview of the NASA TetrUSS CFD package used for the RANS computational approach is presented. Detailed results for three airfoils are presented to compare their stall and post-stall behavior. The results for finite wings at stall and post-stall conditions focus on the effects of taper-ratio and sweep angle, with particular attention to whether the sectional flows can be approximated using two-dimensional flow over a stalled airfoil. While this approximation seems reasonable for unswept wings even at post-stall conditions, significant spanwise flow on stalled swept wings preclude the use of two-dimensional data to model sectional flows on swept wings. Thus, further effort is needed in low-order aerodynamic modeling of swept wings at stalled conditions.

Wider stall space affects behavior, lesion scores, and productivity of gestating sows.

Science.gov (United States)

Salak-Johnson, J L; DeDecker, A E; Levitin, H A; McGarry, B M

2015-10-01

Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( pregnancy progressed, lesion scores increased among sows in CTL ( postural behaviors and sham chew behavior were affected by TRT ( changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL, insufficient floor space in the open-pen area of the FAS system, and gate design of the FLX (e.g., direction of bars and feeder space). These results also indicate that parity and gestational day are additional factors that may exacerbate the effects of restricted stall space or insufficient pen space, further compromising sow well-being.

CULTIVATING PRE-SERVICE TEACHERS’ CLASSROOM MANAGEMENT SKILLS THROUGH TEACHING PRACTICUM: A REFLECTIVE PRACTICE

Directory of Open Access Journals (Sweden)

Debora Tri Ragawanti

2015-01-01

Full Text Available Classroom management is commonly believed to be the key to the success of an instruction. Many student teachers, however, might find it very challenging to handle their classrooms. It is, therefore, necessary to advance their professional practice in the context of a real classroom such as through teaching practicum and reflective practice. This study is aimed at identifying classroom management problems of student-teachers as revealed in their reflective journal entries and to demonstrate how such journal can help them develop their classroom management skills. The participants were 10 student-teachers of the English Department, Satya Wacana Christian University, Salatiga, Central Java, who underwent their teaching practicum at SMP 2 Salatiga. Through the participants’ journals, it was found that the problems lie in managing critical moments, activity, techniques, grouping and seating, authority, tools, and working with people. Further in this study, both pre- and in-service tertiary teachers, curriculum designers, and policy makers will be taken to deeply examine how reflective practice can help cultivate the pre-service’s classroom management skills and to consider the implication for pedagogical practices and innovations in curriculum development.

A Self-Regulatory Approach to Classroom Management: Empowering Students and Teachers

Science.gov (United States)

Alderman, M. Kay; MacDonald, Suzanne

2015-01-01

Development of motivation and self-regulated learning skills can take classroom management beyond the role of maintaining order in the classroom to empower students and teachers for lifetime learning. The authors describe self-regulated learning, student strategies, and the classroom structure that supports motivation and self-regulation.

Inception mechanism and suppression of rotating stall in an axial-flow fan

International Nuclear Information System (INIS)

Nishioka, T

2013-01-01

Inception patterns of rotating stall at two stagger-angle settings for the highly loaded rotor blades were experimentally investigated in a low-speed axial-flow fan. Rotor-tip flow fields were also numerically investigated to clarify the mechanism behind the rotating stall inception. The stall inception patterns depended on the rotor stagger-angle settings. The stall inception from a rotating instability was confirmed at the design stagger-angle settings. The stall inception from a short length-scale stall cell (spike) was also confirmed at the small stagger-angle setting. The spillage of tip-leakage flow and the tip-leakage vortex breakdown influence the rotating stall inception. An air-separator has been developed based on the clarified inception mechanism of rotating stall. The rotating stall was suppressed by the developed air-separator, and the operating range of fan was extended towards low flow rate. The effect of developed air-separator was also confirmed by application to a primary air fan used in a coal fired power plant. It is concluded from these results that the developed air-separator can provide a wide operating range for an axial-flow fan

Monitoring indices of cow comfort in free-stall-housed dairy herds.

Science.gov (United States)

Cook, N B; Bennett, T B; Nordlund, K V

2005-11-01

Indices of cow comfort are used widely by consultants in the dairy industry, with a general understanding that they are representative of lying behavior. This study examines the influence of stall base type (sand or a geotextile mattress filled with rubber crumbs) and time of measurement on 4 indices of comfort collected at hourly intervals in 12 herds, aligned by morning and afternoon milking. Stall base type significantly influenced all indices of comfort. For example, the least squares mean (SE) cow comfort index (proportion of cows touching a stall that are lying down) was 0.76 (0.015) in herds with mattresses compared with 0.86 (0.015) in herds with sand stalls. Significant hourly variation was also identified suggesting that timing of measurement is important. None of the indices of cow comfort derived from the high-yielding group pen was associated with the mean 24-h lying time of 10 sentinel cows whose time budgets were known in each herd. However, the cow comfort index was associated with the herd mean 24-h stall standing time, with the strongest relationships occurring 2 h before the morning and afternoon milking, when stall base type did not significantly influence the association. When measured at these times, we recommend use of the stall standing index (proportion of cows touching a stall that are standing), with values greater than 0.20 being associated with abnormally long herd mean stall standing times greater than 2 h/d.

14 CFR 33.65 - Surge and stall characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... stall characteristics. When the engine is operated in accordance with operating instructions required by...

282 Effective Classroom Management Techniques for Secondary ...

African Journals Online (AJOL)

FIRST LADY

2011-01-18

Jan 18, 2011 ... classroom management effectiveness is a powerful motivator of student's learning. As regards the ... attainment of organizational goals. ... reciprocal behaviour that occurs between individuals such as exchange of information ...

Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

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Simonetta Dovier

2010-09-01

Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

Managing the College Classroom: Perspectives from an Introvert and an Extrovert

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Braden, Stephen W.; Smith, Deborah N.

2006-01-01

One of the biggest challenges facing college instructors in the 21st century is classroom misbehavior. The authors propose that how one handles classroom incivility is a matter of personality type. One of the authors is an extrovert; the other an introvert. The authors discuss personality theory, general classroom management, how to identify…

The Relationship between EFL Teachers' Beliefs and Actual Practices of Classroom Management

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Aliakbari, Mohammad; Heidarzad, Mohsen

2015-01-01

This study aimed at analyzing Iranian EFL teachers' beliefs toward classroom management and the relationship between teachers' beliefs and their actual practices of classroom management in regard with individual variables such as gender, education degree, and teaching experience. The data were collected using a behavior and instructional…

Coin Counter: Gamification for Classroom Management

Science.gov (United States)

Carlson, John; Harris, Ranida; Harris, Ken

2017-01-01

In recent years, gamification has been utilized in a number of different contexts, including educational applications. This paper describes a unique application of coin-based gamification classroom management system in undergraduate programming classes. The coin-based gamification allowed students to earn and spend coins as a form of classroom…

According to Candidate Teachers Views Classroom Management Problems of Teachers in Traditional and Technology-Supported Classrooms

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Tas, Said

2017-01-01

In this research, it is aimed to investigate classroom management problems of middle school 6th and 7th grade teachers in traditional and technology-supported classrooms and differences between them. For this purpose the opinions of the students in the 4th grade of Primary Education Department in Faculty of Education of Süleyman Demirel University…

Working the Crowd: Behavior Management through Strategic Classroom Arrangement

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Martin, Jeff

2015-01-01

Every day in K-12 classrooms across the country, teachers are struggling to keep their students focused and on task during instructional time. There are hundreds of theories floating around about how to manage a classroom effectively, but nothing is as simple or as effective in engaging students as the physical presence of the teacher (Brophy,…

Dynamic stall and 3D effects

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A.; Thor, S.E. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

1996-12-01

The JOULE II project `Dynamic stall and 3D effects` started in January 1994 and was completed in September 1995. The objective of the project has been to increase the understanding of the three-dimensional and unsteady aerodynamics of stall controlled HAWT`s. The objectives have also been to develop `engineering models` suitable for inclusion into aero-elastic codes. The project included the participation of 13 parties within Europe. This paper describes an overview of the work carried out within the project and key results. 3 refs, 4 figs

Teachers' Perceptions of Effective Classroom Management within an Inner-City Middle School.

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Turner, Catana L.

This study was undertaken to obtain descriptive information about teachers' perceptions of effective classroom management within an inner-city middle school. Thirteen teachers in one such school in Tennessee were interviewed about their classroom management behaviors. Teachers appeared to have an elaborate system of beliefs related to the themes…

Both DNA Polymerases δ and ε Contact Active and Stalled Replication Forks Differently

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Yu, Chuanhe; Gan, Haiyun

2017-01-01

ABSTRACT Three DNA polymerases, polymerases α, δ, and ε (Pol α, Pol δ, and Pol ε), are responsible for eukaryotic genome duplication. When DNA replication stress is encountered, DNA synthesis stalls until the stress is ameliorated. However, it is not known whether there is a difference in the association of each polymerase with active and stalled replication forks. Here, we show that each DNA polymerase has a distinct pattern of association with active and stalled replication forks. Pol α is enriched at extending Okazaki fragments of active and stalled forks. In contrast, although Pol δ contacts the nascent lagging strands of active and stalled forks, it binds to only the matured (and not elongating) Okazaki fragments of stalled forks. Pol ε has greater contact with the nascent single-stranded DNA (ssDNA) of the leading strand on active forks than on stalled forks. We propose that the configuration of DNA polymerases at stalled forks facilitates the resumption of DNA synthesis after stress removal. PMID:28784720

Classroom Management and the ADHD Student

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Colberg, Laura

2010-01-01

Meeting the academic needs of a student with Attention Deficit Hyperactivity Disorder (ADHD) can be taxing on teachers and students. This research highlights classroom management strategies that general education teachers might include in their teaching to support the academic growth students with ADHD, while continuing to support all students in…

Airfoil stall interpreted through linear stability analysis

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Busquet, Denis; Juniper, Matthew; Richez, Francois; Marquet, Olivier; Sipp, Denis

2017-11-01

Although airfoil stall has been widely investigated, the origin of this phenomenon, which manifests as a sudden drop of lift, is still not clearly understood. In the specific case of static stall, multiple steady solutions have been identified experimentally and numerically around the stall angle. We are interested here in investigating the stability of these steady solutions so as to first model and then control the dynamics. The study is performed on a 2D helicopter blade airfoil OA209 at low Mach number, M 0.2 and high Reynolds number, Re 1.8 ×106 . Steady RANS computation using a Spalart-Allmaras model is coupled with continuation methods (pseudo-arclength and Newton's method) to obtain steady states for several angles of incidence. The results show one upper branch (high lift), one lower branch (low lift) connected by a middle branch, characterizing an hysteresis phenomenon. A linear stability analysis performed around these equilibrium states highlights a mode responsible for stall, which starts with a low frequency oscillation. A bifurcation scenario is deduced from the behaviour of this mode. To shed light on the nonlinear behavior, a low order nonlinear model is created with the same linear stability behavior as that observed for that airfoil.

Dimensions of Person-Centered Classroom Management

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Freiberg, H. Jerome; Lamb, Stacey M.

2009-01-01

Public opinion trends over the last five decades show that lack of discipline continues to be one of America's top public educational concerns. This trend suggests that alternatives to the traditional model are urgently needed. In this traditional model of classroom management, based on behaviorism and still common in some areas, discipline is…

Student Well-Being Interventions: The Effects of Stress Management Techniques and Gratitude Journaling in the Management Education Classroom

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Flinchbaugh, Carol L.; Moore, E. Whitney G.; Chang, Young K.; May, Douglas R.

2012-01-01

Student well-being in the management classroom is of concern to both educators and managers. Well-being is conceptualized here as students' reduction in stress, enhanced experienced meaning and engagement in the classroom, and, ultimately, heightened satisfaction with life. The authors investigated whether purposeful semester-long classroom…

Pre-Service Secondary Science and Mathematics Teachers' Classroom Management Styles in Turkey

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Yilmaz, Kursad

2009-01-01

The aim of this study is to determine Pre-service secondary science and mathematics teachers' classroom management styles in Turkey. In addition, differences in pre-service secondary science and mathematics teachers' classroom management styles by gender, and field of study were examined. In the study, the survey model was employed. The research…

Understanding Pupil Behaviour: Classroom Management Techniques for Teachers

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Lewis, Ramon

2009-01-01

This book describes a system of successful classroom behaviour management techniques developed by the author over more than twenty-five years. It outlines the difficulties confronting teachers trying to manage pupils' misbehaviour in schools and describes four types of pupil who can be helped to behave responsibly. In "Understanding Pupil…

A Rationale and Bibliography for Classroom Management and Intervention Techniques.

Science.gov (United States)

Karr-Kidwell, PJ

This 51-item bibliography offers a selection of writings on issues and problems related to classroom management and discipline. Most citations concern works written between 1972-1983. Intervention techniques in dealing with deviant behavior are highlighted along with discipline and control in the classroom. Articles on methods of behavior…

Associations between cow hygiene, hock injuries, and free stall usage on US dairy farms.

Science.gov (United States)

Lombard, J E; Tucker, C B; von Keyserlingk, M A G; Kopral, C A; Weary, D M

2010-10-01

This cross-sectional study evaluated cow comfort measures in free stall dairies across the United States as part of the National Animal Health Monitoring System's Dairy 2007 study. The study was conducted in 17 states and evaluations were completed between March 5 and September 5, 2007. Assessors recorded hygiene and hock scores, number of cows housed in the pen, the number of cows standing with only the front feet in a stall, standing fully in a stall, and lying in a stall. Facility design measures included bedding type, bedding quantity, stall length and width, presence of a neck rail or brisket locator, and relevant distances from the rear and bed of the stall. Of the 491 operations that completed the cow comfort assessment, 297 had Holstein cows housed in free stalls and were included in this analysis. Negative binomial models were constructed to evaluate the following outcomes: the number of cows that were very dirty, had severe hock injuries, stood with front feet in the stall, stood with all feet in the stall, and were lying in the stall. Hygiene was better on farms that did not tail dock cows compared with those that did (5.7 vs. 8.8% were dirty) and on farms located in the study's west region compared with those located in the east region (5.2 vs. 9.7% were dirty). Severe hock injuries were less common on farms in the west than those in the east (0.5 vs. 4.1%). In addition, severe hock injuries were less common on farms that used dirt as a stall base or sand as bedding compared with farms that did not. A higher percentage of cows was standing with front feet in the stall at higher ambient temperatures (incidence rate ratio=1.016) and as time since feeding increased (incidence rate ratio=1.030). A lower percentage of cows were standing with front feet in the stall when the stalls were shorter and when there were fewer cows per stall. Standing fully in a stall was performed by a higher percentage of cows during the summer than during the spring (13.6 vs. 8

Assessing the Flipped Classroom in Operations Management: A Pilot Study

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Prashar, Anupama

2015-01-01

The author delved into the results of a flipped classroom pilot conducted for an operations management course module. It assessed students' perception of a flipped learning environment after making them experience it in real time. The classroom environment was construed using a case research approach and students' perceptions were studied using…

A Comparative Study of Three Methodologies for Modeling Dynamic Stall

Science.gov (United States)

Sankar, L.; Rhee, M.; Tung, C.; ZibiBailly, J.; LeBalleur, J. C.; Blaise, D.; Rouzaud, O.

2002-01-01

During the past two decades, there has been an increased reliance on the use of computational fluid dynamics methods for modeling rotors in high speed forward flight. Computational methods are being developed for modeling the shock induced loads on the advancing side, first-principles based modeling of the trailing wake evolution, and for retreating blade stall. The retreating blade dynamic stall problem has received particular attention, because the large variations in lift and pitching moments encountered in dynamic stall can lead to blade vibrations and pitch link fatigue. Restricting to aerodynamics, the numerical prediction of dynamic stall is still a complex and challenging CFD problem, that, even in two dimensions at low speed, gathers the major difficulties of aerodynamics, such as the grid resolution requirements for the viscous phenomena at leading-edge bubbles or in mixing-layers, the bias of the numerical viscosity, and the major difficulties of the physical modeling, such as the turbulence models, the transition models, whose both determinant influences, already present in static maximal-lift or stall computations, are emphasized by the dynamic aspect of the phenomena.

Embracing Ubuntu in managing effective classrooms | Maphalala ...

African Journals Online (AJOL)

Journal Home > Vol 15, No 4 (2017) > ... Ubuntu is founded on three pillars, namely, interpersonal values, intrapersonal values and environmental values. ... the infusion of an African perspective into classroom management which currently considers mainly Western principles in creating a conducive learning environment.

· Attitude towards Computers and Classroom Management of Language School Teachers

Directory of Open Access Journals (Sweden)

Sara Jalali

2014-07-01

Full Text Available Computer-assisted language learning (CALL is the realization of computers in schools and universities which has potentially enhanced the language learning experience inside the classrooms. The integration of the technologies into the classroom demands that the teachers adopt a number of classroom management procedures to maintain a more learner-centered and conducive language learning environment. The current study explored the relationship between computer attitudes and behavior and instructional classroom management approaches implemented by English institute teachers. In so doing, a total of 105 male (n = 27 and female (n = 78 EFL teachers participated in this study. A computer attitude questionnaire adapted from Albirini (2006 and a Behavior and Instructional Management Scale (BIMS adopted from Martin and Sass (2010 were benefitted from for the purpose of collecting the data. The results of the Pearson Correlation Coefficient revealed that there were no significant relationships between attitude and behavior and instructional management across gender. However, it was found that the more male teachers experience tendency toward using computers in their classes, the more teacher-centered their classes become. In addition, the more female teachers are prone to use computers in their classes, the more student-centered and lenient their classes become.

Dynamic stall characterization using modal analysis of phase-averaged pressure distributions

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Harms, Tanner; Nikoueeyan, Pourya; Naughton, Jonathan

2017-11-01

Dynamic stall characterization by means of surface pressure measurements can simplify the time and cost associated with experimental investigation of unsteady airfoil aerodynamics. A unique test capability has been developed at University of Wyoming over the past few years that allows for time and cost efficient measurement of dynamic stall. A variety of rotorcraft and wind turbine airfoils have been tested under a variety of pitch oscillation conditions resulting in a range of dynamic stall behavior. Formation, development and separation of different flow structures are responsible for the complex aerodynamic loading behavior experienced during dynamic stall. These structures have unique signatures on the pressure distribution over the airfoil. This work investigates the statistical behavior of phase-averaged pressure distribution for different types of dynamic stall by means of modal analysis. The use of different modes to identify specific flow structures is being investigated. The use of these modes for different types of dynamic stall can provide a new approach for understanding and categorizing these flows. This work uses airfoil data acquired under Army contract W911W60160C-0021, DOE Grant DE-SC0001261, and a gift from BP Alternative Energy North America, Inc.

A Qualitative Study Investigating Facility Managers' Perceptions of the Classroom Learning Environment

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Parr, Eric Shannon

2017-01-01

Facility managers have the challenge of adhering to community college policies and procedures while fulfilling requirements of administration, students, and teachers concerning specific needs of classroom aesthetics. The role of facility manager and how specific entities affect perceptions of the design and implementation of classroom aesthetics…

Teachers' Reported Knowledge and Implementation of Research-Based Classroom and Behavior Management Strategies

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Moore, Tara C.; Wehby, Joseph H.; Oliver, Regina M.; Chow, Jason C.; Gordon, Jason R.; Mahany, Laura A.

2017-01-01

Teachers' reported knowledge about and implementation of research-based classroom and behavior management strategies were examined. A total of 160 elementary teachers from two districts in different regions of the same state completed the researcher-developed "Survey of Classroom and Behavior Management." On average, teachers reported to…

Classroom Management. TESOL Classroom Practice Series

Science.gov (United States)

Farrell, Thomas S. C., Ed.

2008-01-01

This series captures the dynamics of the contemporary ESOL classroom. It showcases state-of-the-art curricula, materials, tasks, and activities reflecting emerging trends in language education and seeks to build localized language teaching and learning theories based on teachers' and students' unique experiences in and beyond the classroom. Each…

Precautions against axial fan stall in reactor building to Tianwan NPP

International Nuclear Information System (INIS)

Liu Chunlong; Pei Junmin

2011-01-01

The paper introduces the mechanism and harm of rotating stall of axial fans, analyzes the necessity for prevention against axial fan stall in reactor building of Tianwan NPP, introduces the precautions, and then makes an assessment on anti-stall effect of flow separators. It can provide reference for model-selection or reconstruction of similar fans in power stations, and for operation and maintenance of axial fans. (authors)

Strategies in Managing Rapport in Classroom Discussion

OpenAIRE

Reski Reski

2018-01-01

This paper aims to find out the strategies, applied by students in classroom interaction particularly in discussion, to maintain their interpersonal rapport as well as to enhance their rapport management with their fellow students. There are five strategies based on Spencer-Oatey (2008) that the interactants apply in social interactions. The strategies are request, compliments, apologies, gratitude and disagreement. The research is done to see whether the students realize the management of ra...

Ingestive behavior of lambs confined in individual and group stalls.

Science.gov (United States)

Filho, A Eustáquio; Carvalho, G G P; Pires, A J V; Silva, R R; Santos, P E F; Murta, R M; Pereira, F M

2014-02-01

The experiment was conducted to evaluate the ingestive behavior of lambs confined in individual and group stalls. We used thirty-four lambs in their growing phase, aged an average of three months, with mean initial live weight of 17.8±5.2 kg. They were allotted in a completely randomized design with 24 animals kept in individual stalls and 10 animals confined as a group. The experiment lasted for a total of 74 days, and the first 14 days were dedicated to the animals' adaption to the management, facilities and diets. The data collection period lasted 60 days, divided into three 20-d periods for the behavior evaluation. The animals were subjected to five days of visual observation during the experiment period, by the quantification of 24 h a day, with evaluations on the 15th day of each period and an interim evaluation consisting of two consecutive days on the 30th and 31st day of the experiment. The animals confined as a group consumed less (pbehavior.

Classroom Management for Kids Who Won't Sit Still and Other "Bad Apples"

Science.gov (United States)

Cahill, Susan M.

2006-01-01

This article presents a case description of collaboration between an occupational therapist and a general education teacher to develop an effective classroom management system. The classroom management system described here was based on the Alert Program for Self-regulation: How Does Your Engine Run? In addition, the case description provides a…

Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

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Lei Zhang

2014-11-01

Full Text Available Study on the influence of rotating stall on the aerodynamic noise of axial fan has important value to warn of the occurrence of stall through monitoring the noise variations. The present work is to analyze the aerodynamic noise before and after the phenomenon of rotating stall by solving Navier-Stokes equations, coupled with the throttle condition and the broadband noise sources model. The impeller exit rotational Mach number and rotational Reynolds number are separately 0.407 and 8.332 × 106. The results show that the aerodynamic noise source of the fan is mainly the rotation noise under the design condition. The vortex noise accounts for the major part of fan noise after the occurrence of stall, and the maximum acoustic power level of the fan appears in the rotor domains. In the evolution process from the stall inception to the stall cell, the high noise regions of the rotor develop along the radial, circumferential, and axial directions, and the area occupied by high noise regions increases from 33% to 46% impeller channels area. On rotating stall condition, the high noise regions occupying about 46% impeller channels area propagate with the stall cell along the circumferential direction at a half of rotor speed.

Preferences of dairy cows for three stall surface materials with small amounts of bedding.

Science.gov (United States)

Norring, M; Manninen, E; de Passillé, A M; Rushen, J; Saloniemi, H

2010-01-01

Farmers' concerns about the economy, cost of labor, and hygiene have resulted in reduced use of organic bedding in stalls for dairy cows; however, the reduced use of organic bedding possibly impairs cow comfort. The effects of different stall surface materials were evaluated in an unheated building in which only a small amount of bedding was used. The lying time and preferences of 18 cows using 3 stall surface materials (concrete, soft rubber mat, and sand) were compared. All materials were lightly bedded with a small amount of straw, and the amount of straw added to each stall was measured. The cows only had access to stalls of one surface type while their lying time was observed. Lying times were longest on the rubber mats compared with other surfaces (rubber mat 768; concrete 727; sand 707+/-16 min/d). In a preference test, cows had access to 2 of the 3 types of stalls for 10 d and their stall preference was measured. Cows preferred stalls with rubber mats to stalls with a concrete floor (median 73 vs. 18 from a total of 160 observations per day; interquartile range was 27 and 12, respectively), but showed no preference for sand stalls compared with stalls with a concrete floor or with rubber mats. More straw was needed on sand stalls compared with concrete or mat (638+/-13 g/d on sand, 468+/-10 g/d on concrete, and 464+/-8 g/d on rubber mats). Lying times on bedded mats indicated that mats were comfortable for the cows. If availability or cost of bedding material requires limiting the amount of bedding used, rubber mats may help maintain cow comfort. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Examining classroom influences on student perceptions of school climate: the role of classroom management and exclusionary discipline strategies.

Science.gov (United States)

Mitchell, Mary M; Bradshaw, Catherine P

2013-10-01

There is growing emphasis on the use of positive behavior supports rather than exclusionary discipline strategies to promote a positive classroom environment. Yet, there has been limited research examining the association between these two different approaches to classroom management and students' perceptions of school climate. Data from 1902 students within 93 classrooms that were nested within 37 elementary schools were examined using multilevel structural equation modeling procedures to investigate the association between two different classroom management strategies (i.e., exclusionary discipline strategies and the use of positive behavior supports) and student ratings of school climate (i.e., fairness, order and discipline, student-teacher relationship, and academic motivation). The analyses indicated that greater use of exclusionary discipline strategies was associated with lower order and discipline scores, whereas greater use of classroom-based positive behavior supports was associated with higher scores on order and discipline, fairness, and student-teacher relationship. These findings suggest that pre-service training and professional development activities should promote teachers' use of positive behavior support strategies and encourage reduced reliance on exclusionary discipline strategies in order to enhance the school climate and conditions for learning. Copyright © 2013 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Teachers' classroom management variables and students' academic ...

African Journals Online (AJOL)

Teachers' classroom management variables and students' academic achievement in French in Cross River State, Nigeria. JU Emeh, CA Agbor. Abstract. No Abstract. Global Journal of Humanities Vol. 4(1&2) 2005: 25-27. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

Student Perceptions regarding Vocational High School Teachers' Problem Solving Methods against Undesired Behaviors in Classroom Management

Science.gov (United States)

Gulcan, Murat Gurkan

2010-01-01

Teachers' classroom management approach varies depending on several factors such as the social, psychological, cultural and educational status of the student, classroom level, the physical conditions of the school, organization structure. There are different approaches in classroom management. These approaches are gathered under three headings in…

The Effects of Virtual Communities on Group Identity in Classroom Management

Science.gov (United States)

Ho, Tu-Kuang; Lin, Yu-Tzeng

2016-01-01

Group identity is a critical component in developing effective classroom management. While there have been numerous studies on group identity, they have primarily focused on its effects on the physical classroom entity. Advances in information technology, however, have enabled the creation of virtual communities, which have become a vital channel…

Teacher Professional Knowledge and Classroom Management: On the Relation of General Pedagogical Knowledge (GPK) and Classroom Management Expertise (CME)

Science.gov (United States)

König, Johannes; Kramer, Charlotte

2016-01-01

Due to the need for measurement instruments that allow an investigation of teachers' situational cognition and thus go beyond the limited scope of classical paper-and-pencil-tests, we ask how a specific video-based measurement of teachers' classroom management expertise can provide additional information when compared with an established…

Students as Employees: Applying Performance Management Principles in the Management Classroom

Science.gov (United States)

Gillespie, Treena L.; Parry, Richard O.

2009-01-01

The student-as-employee metaphor emphasizes student accountability and participation in learning and provides instructors with work-oriented methods for creating a productive class environment. The authors propose that the tenets of performance management in work organizations can be applied to the classroom. In particular, they focus on three…

Stall Recovery Guidance Algorithms Based on Constrained Control Approaches

Science.gov (United States)

Stepanyan, Vahram; Krishnakumar, Kalmanje; Kaneshige, John; Acosta, Diana

2016-01-01

Aircraft loss-of-control, in particular approach to stall or fully developed stall, is a major factor contributing to aircraft safety risks, which emphasizes the need to develop algorithms that are capable of assisting the pilots to identify the problem and providing guidance to recover the aircraft. In this paper we present several stall recovery guidance algorithms, which are implemented in the background without interfering with flight control system and altering the pilot's actions. They are using input and state constrained control methods to generate guidance signals, which are provided to the pilot in the form of visual cues. It is the pilot's decision to follow these signals. The algorithms are validated in the pilot-in-the loop medium fidelity simulation experiment.

Prediction of active control of subsonic centrifugal compressor rotating stall

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1993-01-01

A mathematical model is developed to predict the suppression of rotating stall in a centrifugal compressor with a vaned diffuser. This model is based on the employment of a control vortical waveform generated upstream of the impeller inlet to damp weak potential disturbances that are the early stages of rotating stall. The control system is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. The model was effective at predicting the stalling behavior of the Purdue Low Speed Centrifugal Compressor for two distinctly different stall patterns. Predictions made for the effect of a controlled inlet vorticity wave on the stability of the compressor show that for minimum control wave magnitudes, on the order of the total inlet disturbance magnitude, significant damping of the instability can be achieved. For control waves of sufficient amplitude, the control phase angle appears to be the most important factor in maintaining a stable condition in the compressor.

An archival analysis of stall warning system effectiveness during airborne icing encounters

Science.gov (United States)

Maris, John Michael

An archival study was conducted to determine the influence of stall warning system performance on aircrew decision-making outcomes during airborne icing encounters. A Conservative Icing Response Bias (CIRB) model was developed to explain the historical variability in aircrew performance in the face of airframe icing. The model combined Bayes' Theorem with Signal Detection Theory (SDT) concepts to yield testable predictions that were evaluated using a Binary Logistic Regression (BLR) multivariate technique applied to two archives: the NASA Aviation Safety Reporting System (ASRS) incident database, and the National Transportation Safety Board (NTSB) accident databases, both covering the period January 1, 1988 to October 2, 2015. The CIRB model predicted that aircrew would experience more incorrect response outcomes in the face of missed stall warnings than with stall warning False Alarms. These predicted outcomes were observed at high significance levels in the final sample of 132 NASA/NTSB cases. The CIRB model had high sensitivity and specificity, and explained 71.5% (Nagelkerke R2) of the variance of aircrew decision-making outcomes during the icing encounters. The reliability and validity metrics derived from this study suggest indicate that the findings are generalizable to the population of U.S. registered turbine-powered aircraft. These findings suggest that icing-related stall events could be reduced if the incidence of stall warning Misses could be minimized. Observed stall warning Misses stemmed from three principal causes: aerodynamic icing effects, which reduced the stall angle-of-attack (AoA) to below the stall warning calibration threshold; tail stalls, which are not monitored by contemporary protection systems; and icing-induced system issues (such as frozen pitot tubes), which compromised stall warning system effectiveness and airframe envelope protections. Each of these sources of missed stall warnings could be addressed by Aerodynamic Performance

Dynamic Characteristics of Rotating Stall in Mixed Flow Pump

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Xiaojun Li

2013-01-01

Full Text Available Rotating stall, a phenomenon that causes flow instabilities and pressure hysteresis by propagating at some fraction of the impeller rotational speed, can occur in centrifugal impellers, mixed impellers, radial diffusers, or axial diffusers. Despite considerable efforts devoted to the study of rotating stall in pumps, the mechanics of this phenomenon are not sufficiently understood. The propagation mechanism and onset of rotating stall are not only affected by inlet flow but also by outlet flow as well as the pressure gradient in the flow passage. As such, the complexity of these concepts is not covered by the classical explanation. To bridge this research gap, the current study investigated prerotation generated at the upstream of the impeller, leakage flow at the tip clearance between the casing and the impeller, and strong reserve flow at the inlet of the diffuser. Understanding these areas will clarify the origin of the positive slope of the head-flow performance curve for a mixed flow pump. Nonuniform pressure distribution and adverse pressure gradient were also introduced to evaluate the onset and development of rotating stall within the diffuser.

Preschool Teachers' Views about Classroom Management Models

Science.gov (United States)

Sahin-Sak, Ikbal Tuba; Sak, Ramazan; Tezel-Sahin, Fatma

2018-01-01

This survey-based quantitative study investigates 310 Turkish preschool teachers' views about classroom management, using the following six models of disciplinary strategy: behavioral change theory, Dreikurs' social discipline model, Canter's assertive discipline model, the Glasser model of discipline, Kounin's model, and Gordon's teacher…

Numerical Investigations of Dynamic Stall Control

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Florin FRUNZULICA

2014-04-01

Full Text Available In this paper we investigated numerically the dynamic stall phenomenon and the possibilities to control it, with application to vertical axis wind turbines (for urban users. The Phenomenon appear at low tip speed ratio (TSR<4 and it has a great impact on structural integrity of the wind turbine and power performances. For this reason we performed a computational study of dynamic stall around NACA 0012 airfoil in pitching motion at relative low Reynolds number (105. Also, we performed the same analysis for four flow control methods: two passive (Gurney flap and slot and two active (blowing jet on the rounded trailing edge and synthetic jet periodically activated. The Results are compared to those of an existing experimental case test.

The Interplay among Emotional Intelligence, Classroom Management, and Language Proficiency of Iranian EFL Teachers

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Hadi Hamidi

2016-06-01

Full Text Available The present study was an attempt to investigate the interplay among Iranian EFL teachers’ emotional intelligence, classroom management, and their general English language proficiency. The result of the data analysis showed that: 1 there was a statistically significant relationship between the emotional intelligence and the classroom management of Iranian EFL teachers, 2 there was a statistically significant relationship between the emotional intelligence and the language proficiency of Iranian EFL teachers, and 3 there was a statistically significant relationship between the classroom management and the language proficiency of Iranian EFL teachers. Teacher trainers, researchers in teacher education, and language teachers may benefit from the findings of the present research.

RFWD3-Dependent Ubiquitination of RPA Regulates Repair at Stalled Replication Forks.

Science.gov (United States)

Elia, Andrew E H; Wang, David C; Willis, Nicholas A; Boardman, Alexander P; Hajdu, Ildiko; Adeyemi, Richard O; Lowry, Elizabeth; Gygi, Steven P; Scully, Ralph; Elledge, Stephen J

2015-10-15

We have used quantitative proteomics to profile ubiquitination in the DNA damage response (DDR). We demonstrate that RPA, which functions as a protein scaffold in the replication stress response, is multiply ubiquitinated upon replication fork stalling. Ubiquitination of RPA occurs on chromatin, involves sites outside its DNA binding channel, does not cause proteasomal degradation, and increases under conditions of fork collapse, suggesting a role in repair at stalled forks. We demonstrate that the E3 ligase RFWD3 mediates RPA ubiquitination. RFWD3 is necessary for replication fork restart, normal repair kinetics during replication stress, and homologous recombination (HR) at stalled replication forks. Mutational analysis suggests that multisite ubiquitination of the entire RPA complex is responsible for repair at stalled forks. Multisite protein group sumoylation is known to promote HR in yeast. Our findings reveal a similar requirement for multisite protein group ubiquitination during HR at stalled forks in mammalian cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Shallow and deep dynamic stall for flapping low Reynolds number airfoils

Energy Technology Data Exchange (ETDEWEB)

Ol, Michael V. [Wright-Patterson AFB, Air Force Research Lab., Dayton, OH (United States); Bernal, Luis; Kang, Chang-Kwon; Shyy, Wei [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States)

2009-05-15

We consider a combined experimental (based on flow visualization, direct force measurement and phase-averaged 2D particle image velocimetry in a water tunnel), computational (2D Reynolds-averaged Navier-Stokes) and theoretical (Theodorsen's formula) approach to study the fluid physics of rigid-airfoil pitch-plunge in nominally two-dimensional conditions. Shallow-stall (combined pitch-plunge) and deep-stall (pure-plunge) are compared at a reduced frequency commensurate with flapping-flight in cruise in nature. Objectives include assessment of how well attached-flow theory can predict lift coefficient even in the presence of significant separation, and how well 2D velocimetry and 2D computation can mutually validate one another. The shallow-stall case shows promising agreement between computation and experiment, while in the deep-stall case, the computation's prediction of flow separation lags that of the experiment, but eventually evinces qualitatively similar leading edge vortex size. Dye injection was found to give good qualitative match with particle image velocimetry in describing leading edge vortex formation and return to flow reattachment, and also gave evidence of strong spanwise growth of flow separation after leading-edge vortex formation. Reynolds number effects, in the range of 10,000-60,000, were found to influence the size of laminar separation in those phases of motion where instantaneous angle of attack was well below stall, but have limited effect on post-stall flowfield behavior. Discrepancy in lift coefficient time history between experiment, theory and computation was mutually comparable, with no clear failure of Theodorsen's formula. This is surprising and encouraging, especially for the deep-stall case, because the theory's assumptions are clearly violated, while its prediction of lift coefficient remains useful for capturing general trends. (orig.)

FBH1 Catalyzes Regression of Stalled Replication Forks

Directory of Open Access Journals (Sweden)

Kasper Fugger

2015-03-01

Full Text Available DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks.

Systems approach to managing educational quality in the engineering classroom

Science.gov (United States)

Grygoryev, Kostyantyn

Today's competitive environment in post-secondary education requires universities to demonstrate the quality of their programs in order to attract financing, and student and academic talent. Despite significant efforts devoted to improving the quality of higher education, systematic, continuous performance measurement and management still have not reached the level where educational outputs and outcomes are actually produced---the classroom. An engineering classroom is a complex environment in which educational inputs are transformed by educational processes into educational outputs and outcomes. By treating a classroom as a system, one can apply tools such as Structural Equation Modeling, Statistical Process Control, and System Dynamics in order to discover cause-and-effect relationships among the classroom variables, control the classroom processes, and evaluate the effect of changes to the course organization, content, and delivery, on educational processes and outcomes. Quality improvement is best achieved through the continuous, systematic application of efforts and resources. Improving classroom processes and outcomes is an iterative process that starts with identifying opportunities for improvement, designing the action plan, implementing the changes, and evaluating their effects. Once the desired objectives are achieved, the quality improvement cycle may start again. The goal of this research was to improve the educational processes and outcomes in an undergraduate engineering management course taught at the University of Alberta. The author was involved with the course, first, as a teaching assistant, and, then, as a primary instructor. The data collected from the course over four years were used to create, first, a static and, then, a dynamic model of a classroom system. By using model output and qualitative feedback from students, changes to the course organization and content were introduced. These changes led to a lower perceived course workload and

A meta-analysis of the effects of classroom management strategies and classroom management programs on students’ academic, behavioral, emotional, and motivational outcomes

NARCIS (Netherlands)

Korpershoek, Hanke; Harms, Truus; de Boer, Hester; van Kuijk, Mechteld; Doolaard, Simone

This meta-analysis examined which classroom management strategies and programs enhanced students’ academic, behavioral, social-emotional, and motivational outcomes in primary education. The analysis included 54 random and nonrandom controlled intervention studies published in the past decade

Prevalence of lameness among dairy cattle in Wisconsin as a function of housing type and stall surface.

Science.gov (United States)

Cook, Nigel B

2003-11-01

To determine the prevalence of lameness as a function of season (summer vs winter), housing type (free stalls vs tie stalls), and stall surface (sand vs any other surface) among lactating dairy cows in Wisconsin. Epidemiologic survey. 3,621 lactating dairy cows in 30 herds. Herds were visited once during the summer and once during the winter, and a locomotion score ranging from 1 (no gait abnormality) to 4 (severe lameness) was assigned to all lactating cows. Cows with a score of 3 or 4 were considered to be clinically lame. Mean +/- SD herd lameness prevalence was 21.1 +/- 10.5% during the summer and 23.9 +/- 10.7% during the winter; these values were significantly different. During the winter, mean prevalence of lameness in free-stall herds with non-sand stall surfaces (33.7%) was significantly higher than prevalences in free-stall herds with sand stall surfaces (21.2%), tie-stall herds with non-sand stall surfaces (21.7%), and tie-stall herds with sand stall surfaces (12.1%). Results suggest that the prevalence of lameness among dairy cattle in Wisconsin is higher than previously thought and that lameness prevalence is associated with season, housing type, and stall surface.

Effective Classroom Management and Instruction: An Exploration of Models. Executive Summary of Final Report.

Science.gov (United States)

Evertson, Carolyn M.; And Others

A summary is presented of the final report, "Effective Classroom Management and Instruction: An Exploration of Models." The final report presents a set of linked investigations of the effects of training teachers in effective classroom management practices in a series of school-based workshops. Four purposes were addressed by the study: (1) to…

Effects of laminar separation bubbles and turbulent separation on airfoil stall

Energy Technology Data Exchange (ETDEWEB)

Dini, P. [Carleton College, Northfield, MN (United States); Coiro, D.P. [Universita di Napoli (Italy)

1997-12-31

An existing two-dimensional, interactive, stall prediction program is extended by improving its laminar separation bubble model. The program now accounts correctly for the effects of the bubble on airfoil performance characteristics when it forms at the mid-chord and on the leading edge. Furthermore, the model can now predict bubble bursting on very sharp leading edges at high angles of attack. The details of the model are discussed in depth. Comparisons of the predicted stall and post-stall pressure distributions show excellent agreement with experimental measurements for several different airfoils at different Reynolds numbers.

Managing Student Behavior in Dual Immersion Classrooms: A Study of Class-Wide Function-Related Intervention Teams.

Science.gov (United States)

Hansen, Blake D; Caldarella, Paul; Williams, Leslie; Wills, Howard P

2017-09-01

Classroom management in dual immersion classrooms includes unique challenges. The teacher must instruct and correct in the L2 language, in which students are beginning learners, and effective classroom management strategies appropriate to the L2 context. Class-Wide Function-Related Intervention Teams (CW-FIT) is a positive classroom management program that teaches social skills and uses group contingencies to improve behavior. The present study examined the ability of French immersion teachers to implement CW-FIT in the L2, including the effects of CW-FIT on teacher praise and reprimand rates and as well as on students' classroom behavior. Social validity was also assessed. A single-subject multiple baseline design with embedded reversals was used to evaluate impact in second-, third-, and fourth-grade dual immersion classrooms. Results indicated that dual immersion teachers were able to implement CW-FIT in L2 with fidelity. The intervention significantly increased teacher praise and improved classroom on-task behavior. Changes in teacher reprimand rates were inconsistent. Students and teachers reported CW-FIT to be socially valid.

Five Approaches to Avoid When Managing the Middle School Classroom

Science.gov (United States)

Englehart, Joshua M.

2013-01-01

Too often, teachers encountering difficulties with classroom management focus only on the students rather than critically examining the influence of their own approaches on student behavior. Given the particular challenges that middle school students present, certain practices and expectations exacerbate management issues, and a lack of awareness…

Interdependence and Management in Bilingual Classrooms. Final Report.

Science.gov (United States)

Cohen, Elizabeth G.; Intili, Jo Ann

Applying industrial organizational theory to classroom management, the authors examined the organization of a complex bilingual curriculum for the effects of shared authority among students and teachers and the effects of shared decision-making among staff. Using a math-science curriculum called "Finding Out: Descubrimiento," the nine…

Visualization and PIV measurement of unsteady flow around a darrieus wind turbine in dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Shibuya, Satoshi; Fujisawa, Nobuyuki; Takano, Tsuyoshi [Dept. of Mechanical and Production Engineering, Niigata Univ., Niigata (Japan)

1999-07-01

Flow around a Darrieus wind turbine in dynamic stall is studied by flow visualization and PIV (particle image velocimeter) measurement in a rotating frame of reference, which allows the successive observation of the dynamic stall over the blade. The qualitative features of the flow field in dynamic stall observed by the flow visualization, such as the formation and shedding of the stall vortices, are quantitatively reproduced in the instantaneous velocity distributions near the blade by using PIV. These results indicate that two pairs of stall vortices are generated from the blade during one rotation of the blade and that the size and the generating blade angle of the stall vortices are enlarged as the tip-speed ratio decreases. These stall vortices are produced by the in-flow motion from the outer surface to the inner surface through the trailing edge of the blade and the flow separation over the inner surface of the blade. (author)

Identify the Rotating Stall in Centrifugal Compressors by Fractal Dimension in Reconstructed Phase Space

Directory of Open Access Journals (Sweden)

Le Wang

2015-11-01

Full Text Available Based on phase space reconstruction and fractal dynamics in nonlinear dynamics, a method is proposed to extract and analyze the dynamics of the rotating stall in the impeller of centrifugal compressor, and some numerical examples are given to verify the results as well. First, the rotating stall of an existing low speed centrifugal compressor (LSCC is numerically simulated, and the time series of pressure in the rotating stall is obtained at various locations near the impeller outlet. Then, the phase space reconstruction is applied to these pressure time series, and a low-dimensional dynamical system, which the dynamics properties are included in, is reconstructed. In phase space reconstruction, C–C method is used to obtain the key parameters, such as time delay and the embedding dimension of the reconstructed phase space. Further, the fractal characteristics of the rotating stall are analyzed in detail, and the fractal dimensions are given for some examples to measure the complexity of the flow in the post-rotating stall. The results show that the fractal structures could reveal the intrinsic dynamics of the rotating stall flow and could be considered as a characteristic to identify the rotating stall.

Pre-School Teachers' Classroom Management Competency and the Factors Affecting Their Understanding of Discipline

Science.gov (United States)

Buyuktaskapu Soydan, Sema; Alakoc, Pirpir; Ozturk Samur, Ayse; Angin, Duriye Esra

2018-01-01

Purpose: This research was carried out to determine the classroom management competency and the levels of perception of understanding of discipline among preschool teachers, the effect of their classroom management competency and understanding of discipline on child-teacher relationship, the relationship between interpersonal problem-solving and…

An airloads theory for morphing airfoils in dynamic stall with experimental correlation

Science.gov (United States)

Ahaus, Loren A.

Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, future rotorcraft may incorporate dynamically morphing airfoils (trailing-edge aps, dynamic camber, dynamic droop, etc.). Reduced-order aerodynamic models are needed for preliminary design and ight simulation. A unified model for predicting the airloads on a morphing airfoil in dynamic stall is presented, consisting of three components. First, a linear airloads theory allows for arbitrary airfoil deformations consistent with a morphing airfoil. Second, to capture the effects of the wake, the airloads theory is coupled to an induced ow model. Third, the overshoot and time delay associated with dynamic stall are modeled by a second-order dynamic filter, along the lines of the ONERA dynamic stall model. This paper presents a unified airloads model that allows arbitrary airfoil morphing with dynamic stall. Correlations with experimental data validate the theory.

An Evaluation of CHAMPS: A Classroom Management Program

Science.gov (United States)

Minnear, Holly J.

2015-01-01

This dissertation was designed to examine the impact of Conversation, Help, Activity, Movement, Participation, Success (CHAMPS), a classroom management program in elementary schools in a district in North Carolina. The participants included principals and teachers who attended a 2-day training course and implemented the CHAMPS program at their…

A Comparison of Traditional and Alternative Certification Routes on Classroom Management

Directory of Open Access Journals (Sweden)

Brian Uriegas

2014-10-01

Full Text Available In Texas, there are different ways teachers can attain certification. Thus, teachers are entering the classroom through various certification routes with varying levels of training as the traditional and alternative programs differ in their requirements. Classroom management can determine the success or failure of teachers and students. The research involved in this study attempted to determine whether university-certified teachers differ from alternatively certified teachers in the area of classroom management as determined by referrals, while controlling for level of education, years of teaching experience, age, race, and gender at both middle and high school levels. The population for this study was the middle and high school teachers in one rural south central Texas school district. Data were collected from the school district’s personnel database as well as from the campus-level administrators. Hierarchical regressions were used to test null hypotheses and recommendations were suggested.

Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment

Directory of Open Access Journals (Sweden)

V. V. N. K. Satish Koyyalamudi

2016-01-01

Full Text Available The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.

When Social Identities Collide: Commentary on "Gender in the Management Education Classroom"

Science.gov (United States)

Patton, Eric

2010-01-01

This commentary to "Gender in the Management Education Classroom" (Bilimoria, O'Neil, Hopkins, & Murphy, 2010) employs social identity and self-categorization theory to analyze the incident described in the article. In any MBA classroom, students are dealing with multiple group memberships. Similar to workplace settings, when the focus is on…

The Effectiveness of Classroom Management in English Language Teaching and Learning for Tenth Graders of SMA Panjura Malang

OpenAIRE

ASTUTI, AGRIT DWI

2015-01-01

Keywords: effective classroom, classroom management, English language teaching, tenth graders students of Senior High School. English is International language that should be learnt by people in every country, included Indonesia. Effective English language teaching and learning process was needed for students in Indonesia. Whether classroom is effective to support teaching and learning process was influenced by many factors such as teaching strategy, managing classroom and students themselves...

Load prediction of stall regulated wind turbines

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A.; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden); Carlen, I. [Chalmers Univ. of Technology, Goeteborg (Sweden). Div. of Marine Structural Engineering; Ganander, H. [Teknikgruppen AB, Sollentua (Sweden)

1996-12-01

Measurements of blade loads on a turbine situated in a small wind farm shows that the highest blade loads occur during operation close to the peak power i.e. when the turbine operates in the stall region. In this study the extensive experimental data base has been utilised to compare loads in selected campaigns with corresponding load predictions. The predictions are based on time domain simulations of the wind turbine structure, performed by the aeroelastic code VIDYN. In the calculations a model were adopted in order to include the effects of dynamic stall. This paper describes the work carried out so far within the project and key results. 5 refs, 10 figs

Alleviation of spike stall in axial compressors utilizing grooved casing treatment

Directory of Open Access Journals (Sweden)

Reza Taghavi-Zenouz

2015-06-01

Full Text Available This article deals with application of grooved type casing treatment for suppression of spike stall in an isolated axial compressor rotor blade row. The continuous grooved casing treatment covering the whole compressor circumference is of 1.8 mm in depth and located between 90% and 108% chord of the blade tip as measured from leading edge. The method of investigation is based on time-accurate three-dimensional full annulus numerical simulations for cases with and without casing treatment. Discretization of the Navier–Stokes equations has been carried out based on an upwind second-order scheme and k-ω-SST (Shear Stress Transport turbulence modeling has been used for estimation of eddy viscosity. Time-dependent flow structure results for the smooth casing reveal that there are two criteria for spike stall inception known as leading edge spillage and trailing edge backflow, which occur at specific mass flow rates in near-stall conditions. In this case, two dominant stall cells of different sizes could be observed. The larger one is caused by the spike stall covering roughly two blade passages in the circumferential direction and about 25% span in the radial direction. Spike stall disturbances are accompanied by lower frequencies and higher amplitudes of the pressure signals. Casing treatment causes flow blockages to reduce due to alleviation of backflow regions, which in turn reduces the total pressure loss and increases the axial velocity in the blade tip gap region, as well as tip leakage flow fluctuation at higher frequencies and lower amplitudes. Eventually, it can be concluded that the casing treatment of the stepped tip gap type could increase the stall margin of the compressor. This fact is basically due to retarding the movement of the interface region between incoming and tip leakage flows towards the rotor leading edge plane and suppressing the reversed flow around the blade trailing edge.

Classcraft: From Gamification to Ludicization of Classroom Management

Science.gov (United States)

Sanchez, Eric; Young, Shawn; Jouneau-Sion, Caroline

2017-01-01

In this article, we discuss the concept of gamification, based on a literature review and preliminary feedback from teachers using "Classcraft," a role-playing game supported by a digital platform and a mobile application that were developed to answer high school teachers' classroom management needs. Our results come from two experiments…

Development of High Speed Imaging and Analysis Techniques Compressible Dynamics Stall

Science.gov (United States)

Chandrasekhara, M. S.; Carr, L. W.; Wilder, M. C.; Davis, Sanford S. (Technical Monitor)

1996-01-01

Dynamic stall has limited the flight envelope of helicopters for many years. The problem has been studied in the laboratory as well as in flight, but most research, even in the laboratory, has been restricted to surface measurement techniques such as pressure transducers or skin friction gauges, except at low speed. From this research, it became apparent that flow visualization tests performed at Mach numbers representing actual flight conditions were needed if the complex physics associated with dynamic stall was to be properly understood. However, visualization of the flow field during compressible conditions required carefully aligned and meticulously reconstructed holographic interferometry. As part of a long-range effort focused on exposing of the physics of compressible dynamic stall, a research wind tunnel was developed at NASA Ames Research Center which permits visual access to the full flow field surrounding an oscillating airfoil during compressible dynamic stall. Initially, a stroboscopic schlieren technique was used for visualization of the stall process, but the primary research tool has been point diffraction interferometry(PDI), a technique carefully optimized for use in th is project. A review of the process of development of PDI will be presented in the full paper. One of the most valuable aspects of PDI is the fact that interferograms are produced in real time on a continuous basis. The use of a rapidly-pulsed laser makes this practical; a discussion of this approach will be presented in the full paper. This rapid pulsing(up to 40,000 pulses/sec) produces interferograms of the rapidly developing dynamic stall field in sufficient resolution(both in space and time) that the fluid physics of the compressible dynamic stall flowfield can be quantitatively determined, including the gradients of pressure in space and time. This permits analysis of the influence of the effect of pitch rate, Mach number, Reynolds number, amplitude of oscillation, and other

Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

A Meta-Analysis of the Effects of Classroom Management Strategies and Classroom Management Programs on Students' Academic, Behavioral, Emotional, and Motivational Outcomes

Science.gov (United States)

Korpershoek, Hanke; Harms, Truus; de Boer, Hester; van Kuijk, Mechteld; Doolaard, Simone

2016-01-01

This meta-analysis examined which classroom management strategies and programs enhanced students' academic, behavioral, social-emotional, and motivational outcomes in primary education. The analysis included 54 random and nonrandom controlled intervention studies published in the past decade (2003-2013). Results showed small but significant…

Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

International Nuclear Information System (INIS)

Lim, Byeung Jun; Kwon, Se Jin; Park, Tae Choon

2014-01-01

Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.

An online app platform enhances collaborative medical student group learning and classroom management.

Science.gov (United States)

Peacock, Justin G; Grande, Joseph P

2016-01-01

The authors presented their results in effectively using a free and widely-accessible online app platform to manage and teach a first-year pathology course at Mayo Medical School. The authors utilized the Google "Blogger", "Forms", "Flubaroo", "Sheets", "Docs", and "Slides" apps to effectively build a collaborative classroom teaching and management system. Students were surveyed on the use of the app platform in the classroom, and 44 (94%) students responded. Thirty-two (73%) of the students reported that "Blogger" was an effective place for online discussion of pathology topics and questions. 43 (98%) of the students reported that the "Forms/Flubaroo" grade-reporting system was helpful. 40 (91%) of the students used the remote, collaborative features of "Slides" to create team-based learning presentations, and 39 (89%) of the students found those collaborative features helpful. "Docs" helped teaching assistants to collaboratively create study guides or grading rubrics. Overall, 41 (93%) of the students found that the app platform was helpful in establishing a collaborative, online classroom environment. The online app platform allowed faculty to build an efficient and effective classroom teaching and management system. The ease of accessibility and opportunity for collaboration allowed for collaborative learning, grading, and teaching.

Stability Analysis for Rotating Stall Dynamics in Axial Flow Compressors

Science.gov (United States)

1999-01-01

modes determines collectively local stability of the compressor model. Explicit conditions are obtained for local stability of rotating stall which...critical modes determines the stability for rotating stall collectively . We point out that although in a special case our stability condition for...strict crossing assumption implies that the zero solution changes its stability as ~, crosses ~’c. For instance, odk (yc ) > 0 implies that the zero

Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

DEFF Research Database (Denmark)

Guntur, Srinivas; Sørensen, Niels N.; Schreck, Scott

2016-01-01

a reduced order dynamic stall model that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional two-dimensional, non-rotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared...... Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation; (2) data from unsteady delayed detached eddy simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D; and (3) data from...... with those from the dynamic stall model. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in two-dimensional flow to be investigated. Results indicated a good qualitative...

Experimental investigation on the effects of non-cyclical frequency and amplitude variation on dynamic stall

Science.gov (United States)

Heintz, Kyle C.

An experimental study of a cambered airfoil undergoing non-cyclical, transient pitch trajectories and the resulting effects on the dynamic stall phenomenon is presented. Surface pressure measurements and airfoil incidence angle are acquired simultaneously to resolve instantaneous aerodynamic load coefficients at Mach numbers ranging from 0.2 to 0.4. Derived from these coefficients are various formulations of the aerodynamic damping factor, referred to copiously throughout. Using a two-motor mechanism, each providing independent frequency and amplitude input to the airfoil, unique pitch motions can be implemented by actively controlling the phase between inputs. This work primarily focuses on three pitch motion schemas, the first of which is a "chirp" style trajectory featuring concurrent exponential frequency growth and amplitude decay. Second, these parameters are tested separately to determine their individual contributions. Lastly, a novel dual harmonic pitch motion is devised which rapidly traverses dynamic stall regimes on an inter-cycle basis by modulating the static-stall penetration angle. Throughout all results presented, there is evidence that for consecutive pitch-cycles, the process of dynamic stall is affected when prior oscillations prior have undergone deeper stall-penetration angles. In other words when stall-penetration is descending, retreating from a regime of light or deep stall, statistics of load coefficients, such as damping coefficient, maximum lift, minimum quarter-chord moment, and their phase relationships, do not match the values seen when stall-penetration was growing. The outcomes herein suggest that the airfoil retains some memory of previous flow separation which has the potential to change the influence of the dynamic stall vortex.

Classroom organization and management for effective teaching and learning at the intermediate phase in the Mafikeng District of the North West Province / Mmapula Joyce Segatlhe

OpenAIRE

Segatlhe, Mmapula Joyce

2003-01-01

This study concerns itself with issues relating to classroom management and organisation for effective teaching and learning. The study focuses on these aspects of classroom management and organisation: What is classroom management? What is effective within the management of the classroom? What role does or should a teacher play in classroom management? What contributions do discipline and 'tasks' make to effective classroom management in the Mafikeng District? Eighteen primary...

On the Relationship between EFL Teachers' Classroom Management Approaches and the Dominant Teaching Style: A Mixed Method Study

Science.gov (United States)

Kazemi, Ali; Soleimani, Neda

2016-01-01

As a factor contributing to a successful teaching career, classroom management can be affected by many latent and explicit variables. In this mixed method study, the researchers sought to scrutinize the possible connections among EFL teachers' classroom management approaches at two dimensions of behavior management and instructional management and…

Does Classroom Management Coursework Influence Pre-service Teachers' Perceived Preparedness or Confidence?

Science.gov (United States)

O'Neill, Sue; Stephenson, Jennifer

2012-01-01

There has been conjecture that completing focused coursework units on classroom management during pre-service teacher preparation might lead to increased feelings of preparedness and confidence. This study reports the preparedness in managing specific problem behaviours, familiarity, and confidence in using management strategies and models of…

Assessment of special education teachers about their skills for classroom management

OpenAIRE

Černe, Maja

2016-01-01

The aim of this diploma thesis was to research the perceived self-efficacy in classroom management among special education teachers who teach in an adapted education program with lower educational standards. We wanted to evaluate how prepared are they to meet the challenges in maintaining classroom discipline. In the theoretical part of the thesis, we described the characteristics of pupils with mild intellectual disabilities and their education in an adapted educational program with lower ed...

Enhancing BEM simulations of a stalled wind turbine using a 3D correction model

Science.gov (United States)

Bangga, Galih; Hutomo, Go; Syawitri, Taurista; Kusumadewi, Tri; Oktavia, Winda; Sabila, Ahmad; Setiadi, Herlambang; Faisal, Muhamad; Hendranata, Yongki; Lastomo, Dwi; Putra, Louis; Kristiadi, Stefanus; Bumi, Ilmi

2018-03-01

Nowadays wind turbine rotors are usually employed with pitch control mechanisms to avoid deep stall conditions. Despite that, wind turbines often operate under pitch fault situation causing massive flow separation to occur. Pure Blade Element Momentum (BEM) approaches are not designed for this situation and inaccurate load predictions are already expected. In the present studies, BEM predictions are improved through the inclusion of a stall delay model for a wind turbine rotor operating under pitch fault situation of -2.3° towards stall. The accuracy of the stall delay model is assessed by comparing the results with available Computational Fluid Dynamics (CFD) simulations data.

Teachers’ Classroom management and Quality Assurance of Students’ Learning Outcome in Secondary Schools in Ondo State, Nigeria

OpenAIRE

AYENI, Adeolu Joshua

2017-01-01

Abstract. The study assessed teachers’ classroom management strategies, the level of teachers' classroom instructional tasks and determined the effect on students’ academic performance, and further examined the constraints in classroom management in secondary schools in Akure South Local Government Area of Ondo State, Nigeria. Descriptive survey and ex post facto research designs were adopted. Five research questions and two hypotheses were formulated to guide the study. The sample consisted ...

Information Management Tools for Classrooms: Exploring Database Management Systems. Technical Report No. 28.

Science.gov (United States)

Freeman, Carla; And Others

In order to understand how the database software or online database functioned in the overall curricula, the use of database management (DBMs) systems was studied at eight elementary and middle schools through classroom observation and interviews with teachers and administrators, librarians, and students. Three overall areas were addressed:…

Authoritative Classroom Management: How Control and Nurturance Work Together

Science.gov (United States)

Walker, Joan M. T.

2009-01-01

Despite broad recognition that teaching excellence requires meeting students' intellectual and social needs, teachers struggle to manage--and learning theory struggles to explain--the interplay between the academic and social dimensions of classroom life. Drawing from research on parenting and child development, the author offers parenting style…

The Relationship between Teachers' Implementation of Classroom Management Practices and Student Behavior in Elementary School

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Gage, Nicholas A.; Scott, Terrance; Hirn, Regina; MacSuga-Gage, Ashley S.

2018-01-01

Teachers' classroom management practices have a direct impact on their students' probability of success. Evidence-based classroom management practices include (a) active instruction and supervision of students (i.e., teaching), (b) opportunities for students to respond, and (c) feedback to students. In this study, we examined the degree to which…

Prediction of dynamic loads and induced vibrations in stall

Energy Technology Data Exchange (ETDEWEB)

Thirstrup Petersen, J.; Aagaard Madsen, H. [Risoe National Lab. (Denmark); Bjoerck, A. [Aeronautical Research Inst. of Sweden (Sweden); Enevoldsen, P. [Bonus Energy A/S (Denmark); Oeye, S. [The Technical Univ. of Denmark (Denmark); Ganander, H. [Teknikgruppen AB (Sweden); Winkelaar, D. [Netherlands Energy Research Foundation (Netherlands)

1998-05-01

Results from research in an EC Joule-III project and from national projects are presented. The objectives are improvement of design methods for stall regulated wind turbines with emphasis on stall induced vibrations and dynamic stall. The primary concern is limitation of the edgewise vibrations in the fundamental blade natural mode shape, which have caused trouble on modern wind turbines of approximate size 500 kW nominal power and 40 m rotor diameter. A theoretical study of quasi-steady aerodynamics confirms that the vibrations are driven basically by energy supplied from the aerodynamic forces during stalled operation. This energy exchange is equivalent to negative aerodynamic damping. The theoretical approach identifies the main parameters controlling the phenomenon. These parameters describe the steady and the dynamic airfoil characteristics, the overall aerodynamic layout of the blade, e.g. chord length and twist, the structural properties of the blade, e.g. structural damping and properties controlling the resulting vibration direction. Furthermore, full aeroelastic calculations and comparison with measurements show that the properties of the supporting structure, i.e. the main shaft, the nacelle and the tower, are important, as the global vibration of the rotor on its support may exchange energy with the blade vibration, when the blade natural frequency is close to one of the frequencies of the coupled rotor tilt-yaw mode shapes, usually denoted the global rotor whirl frequencies. It is confirmed that the influence of changing the primary design parameters can be determined by use of qualified aeroelastic calculations. Presented design guidelines therefore build on both the simple quasi-steady models, which can be used for the preliminary choice of the design variables mentioned above, and on full aeroelastic calculations. The aeroelastic calculations refine the design basis and should be used for choosing the final design variables and for final

Urban Teachers' Professed Classroom Management Strategies: Reflections of Culturally Responsive Teaching

Science.gov (United States)

Brown, Dave F.

2004-01-01

Thirteen urban educators teaching from 1st through 12th grade selected from 7 cities across the United States were interviewed in this qualitative research study to determine if the classroom management strategies they use reflect the research on culturally responsive teaching. Participants revealed using several management strategies that reflect…

A theory of post-stall transients in axial compression systems. I - Development of equations

Science.gov (United States)

Moore, F. K.; Greitzer, E. M.

1985-01-01

An approximate theory is presented for post-stall transients in multistage axial compression systems. The theory leads to a set of three simultaneous nonlinear third-order partial differential equations for pressure rise, and average and disturbed values of flow coefficient, as functions of time and angle around the compressor. By a Galerkin procedure, angular dependence is averaged, and the equations become first order in time. These final equations are capable of describing the growth and possible decay of a rotating-stall cell during a compressor mass-flow transient. It is shown how rotating-stall-like and surgelike motions are coupled through these equations, and also how the instantaneous compressor pumping characteristic changes during the transient stall process.

Simulating Variation in Order to Learn Classroom Management

Science.gov (United States)

Ragnemalm, Eva L.; Samuelsson, Marcus

2016-01-01

Classroom management is an important part of learning to be a teacher. The variation theory of learning provides the insight that it is important to vary the critical aspects of any task or subject that is to be learned. Simulation technology is useful in order to provide a controlled environment for that variation, and text as a medium gives the…

A Comparison of Teacher Classroom Management Practices and Presage Variables on High and Low Performing Elementary Schools

Science.gov (United States)

Kinloch, Karen Elizabeth

2013-01-01

According to an extensive review of the literature, effective instructional delivery and "classroom management" practices are critical factors to elevate student achievement (Shindler, Jones, Williams, Taylor, & Cadenas, 2012). The purpose of this study was to analyze a comparison of classroom management practices on student…

Active Suppression of Rotating Stall Inception with Distributed Jet Actuation

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Huu Duc Vo

2007-01-01

Full Text Available An analytical and experimental investigation of the effectiveness of full-span distributed jet actuation for active suppression of long length-scale rotating stall inception is carried out. Detailed modeling and experimental verification highlight the important effects of mass addition, discrete injectors, and feedback dynamics, which may be overlooked in preliminary theoretical studies of active control with jet injection. A model of the compression system incorporating nonideal injection and feedback dynamics is verified with forced response measurements to predict the right trends in the movement of the critical pole associated with the stall precursor. Active control experiments with proportional feedback control show that the predicted stall precursors are suppressed to give a 5.5% range extension in compressor flow coefficient. In addition, results suggest that the proposed model could be used to design a more sophisticated controller to further improve performance while reducing actuator bandwidth requirements.

Development and application of a dynamic stall model for rotating wind turbine blades

International Nuclear Information System (INIS)

Xu, B F; Yuan, Y; Wang, T G

2014-01-01

In unsteady conditions of wind turbines, both the dynamic stall phenomenon and the three-dimensional (3D) rotational effect affect the rotor aerodynamics. The dynamic stall mechanism for rotating wind turbine blades is first investigated. Through the comparison of the aerodynamic data between the rotating blade and the two-dimensional (2D) airfoil, the normal force slope in the attached flow and the separation point expression in the separated flow are modified in the Beddoes-Leishman (B-L) dynamic stall model for rotating NREL wind turbine blades. The modified model is validated by the comparison between the calculation results and the experimental results of the lift and drag coefficients at different radial positions. Both the hysteresis loop shapes and the calculation values are closer to the experiment than the 2D dynamic stall model. The present dynamic stall model is then coupled to a free vortex wake model. The coupled model is used to calculate the unsteady blade aerodynamic loads and the low speed shaft torque of the NREL wind turbine in a yawed condition. The accuracy is greatly improved by the corrections presented in the paper

On the relationship between EFL teachers’ classroom management approaches and the dominant teaching style: A mixed method study

OpenAIRE

Ali Kazemi; Neda Soleimani

2016-01-01

As a factor contributing to a successful teaching career, classroom management can be affected by many latent and explicit variables. In this mixed method study, the researchers sought to scrutinize the possible connections among EFL teachers' classroom management approaches at two dimensions of behavior management and instructional management and the dominant teaching style. To this end, the researchers administered the Behavior and Instructional Management Scale (BIMS) ...

Predicting Language Teachers' Classroom Management Orientations on the Basis of Their Computer Attitude and Demographic Characteristics

Science.gov (United States)

Jalali, Sara; Panahzade, Vahid

2014-01-01

The advent of modern technologies has had a remarkable role in revolutionizing the classroom setting. It is, therefore, incumbent on teachers to utilize strategies for effective managing of the change. The aim of the present study was to find out English as a Foreign Language (EFL) teachers' beliefs regarding classroom management. In so doing, the…

Comparison of driven and simulated "free" stall flutter in a wind tunnel

Science.gov (United States)

Culler, Ethan; Farnsworth, John; Fagley, Casey; Seidel, Jurgen

2016-11-01

Stall flutter and dynamic stall have received a significant amount of attention over the years. To experimentally study this problem, the body undergoing stall flutter is typically driven at a characteristic, single frequency sinusoid with a prescribed pitching amplitude and mean angle of attack offset. This approach allows for testing with repeatable kinematics, however it effectively decouples the structural motion from the aerodynamic forcing. Recent results suggest that this driven approach could misrepresent the forcing observed in a "free" stall flutter scenario. Specifically, a dynamically pitched rigid NACA 0018 wing section was tested in the wind tunnel under two modes of operation: (1) Cyber-Physical where "free" stall flutter was physically simulated through a custom motor-control system modeling a torsional spring and (2) Direct Motor-Driven Dynamic Pitch at a single frequency sinusoid representative of the cyber-physical motion. The time-resolved pitch angle and moment were directly measured and compared for each case. It was found that small deviations in the pitch angle trajectory between these two operational cases generate significantly different aerodynamic pitching moments on the wing section, with the pitching moments nearly 180o out of phase in some cases. This work is supported by the Air Force Office of Scientific Research through the Flow Interactions and Control Program and by the National Defense Science and Engineering Graduate Fellowship Program.

The Relationship between Critical Thinking Abilities and Classroom Management Skills of High School Teachers

Science.gov (United States)

Demirdag, Seyithan

2015-01-01

High school teachers experience difficulties while providing effective teaching approaches in their classrooms. Some of the difficulties are associated with the lack of classroom management skills and critical thinking abilities. This quantitative study includes non-random selection of the participants and aims to examine critical thinking…

Simulasi Numerik Dynamic Stall Pada Airfoil Yang Berosilasi

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Galih S.T.A. Bangga

2012-09-01

Full Text Available Kebutuhan analisa pada sudu helikopter, kompresor, kincir angin dan struktur streamline lainya yang beroperasi pada angle of attack yang tinggi dan melibatkan instationary effects yang disebut dynamic stall menjadi semakin penting. Fenomena ini ditandai dengan naiknya dynamic lift melewati static lift maksimum pada critical static stall angle, vortex yang terbentuk pada leading edge mengakibatkan naiknya suction contribution yang kemudian terkonveksi sepanjang permukaan hingga mencapai trailling edge diikuti terbentuknya trailling edge vortex yang menunjukkan terjadinya lift stall. Fenomena ini sangat berbahaya terhadap struktur airfoil itu sendiri. Secara umum, beban fatique yang ditimbulkan oleh adanya efek histerisis karena fluktuasi gaya lift akibat induksi vibrasi lebih besar dibandingkan kondisi statis. Simulasi numerik dilakukan secara 2D dengan menggunakan profil Boeing-Vertol V23010-1.58 pada α0 = 14.92°. Standard-kω dan SST-kω digunakan sebagai URANS turbulence modelling. Model osilasi dari airfoil disusun dalam suatu user defined function (UDF. Gerakan meshing beserta airfoil diakomodasi dengan menggunakan dynamic mesh approach. Simulasi numerik menunjukkan bahwa, model SST-kω menunjukkan performa yang lebih baik dibandingkan dengan Standard-kω. Fenomena travelling vortex yang terjadi mampu ditangkap dengan baik, meski pada angle of attack yang tinggi URANS turbulence model gagal memprediksikan fenomena yang terjadi karena dominasi efek 3D.

Effects of alley and stall surfaces on indices of claw and leg health in dairy cattle housed in a free-stall barn.

Science.gov (United States)

Vokey, F J; Guard, C L; Erb, H N; Galton, D M

2001-12-01

A 15-wk 2 x 3 factorial trial in a university dairy herd compared the effects of two alley surfaces and three free-stall beds on indices of lameness. Alley surfaces were grooved concrete (Ct) or 1.9-cm-thick interlocking rubber mats (R). Stalls were deep sand (S), rubber mattresses (M), or concrete (C). Mattress and concrete stalls were bedded with sawdust. At wk 1 and 15, the hind claws and hocks of 120 primi- (n = 69) and multiparous (n = 51) cows were scored for lesions and three claw measurements (dorsal wall length, heel depth, and toe angle) were recorded. Rates of lateral and medial claw growth and wear were calculated by measuring the migration of a reference mark away from the coronet. Digital photographs of claw surfaces were used to rescore claw lesions. Clinical lameness was evaluated by assigning a locomotion score from 1 to 4 to each cow during wk 1, 5, 10, and 14. Digital dermatitis (present/not present) and interdigital dermatitis (mild, moderate, or severe) were recorded at wk 15. The number of days that cows spent in a hospital barn was recorded. Before assignment, cows were professionally foot trimmed, sorted by initial claw lesion score, and then randomized in consecutive blocks of three to stall treatments. Photograph scores were highly repeatable. Nonparametric statistical techniques were used for analyses of rank data. Claw lesion score increased significantly for all treatment groups except RC and RS; however, when early lactation cows were excluded, no differences were found between treatment groups. Hock scores increased significantly more for cows in CtC than in CtS or RS. Significantly more animals from RC spent more than 10 d in the hospital pen compared with RM and RS. Groups did not significantly differ for clinical lameness. Cows in RS and RC had significantly lower rates for lateral claw net growth than those in CtM. Having moderate or severe interdigital dermatitis at wk 15 was associated with greater increases in claw lesion score

MANAGING DISRUPTIVE BEHAVIOR OF STUDENTS IN LANGUAGE CLASSROOM

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Siti Khasinah

2017-05-01

Full Text Available This article describes students’ disruptive behaviors in language classroom that may greatly affect language teaching and learning process, especially in ESL or EFL classes. Teachers should know what disruptive behavior is to enable them to deal with problems occurred in their classroom or to take preventive actions to keep their students well-behaved during the class. This can reduce the occurrence of misbehavior of students in their classroom. To prevent disruption in the classroom, teachers should establish behavioral expectations in the first day of the semester and the expectations can be based on students attendance, arrivals and departures, class participation, full English speaking, and other appropriate conducts in the syllabus and discuss them at the outset of the term. The agreement is then assigned as a learning contract or a code of conducts with which bounds the whole class. Consequently, whenever students are misbehaved, teachers and other students will directly know and recognize that the behaviors are out of the code. There are factors reasoning students to behave badly, so teachers as trouble solvers have to find appropriate strategies that are effective in helping students keep the code. Otherwise, the disruptions will escalate quickly and the problems will increase in numbers rapidly and finally, teachers will have to work very hard to avoid teaching failure and “losing face” when they cannot manage the disruption as listed in the expectation.

Relationship between Academic Optimism and Classroom Management Styles of Teachers--Case Study: Elementary School Teachers in Isfahan

Science.gov (United States)

Moghtadaie, L.; Hoveida, R.

2015-01-01

The purpose of this study was to investigate the relationship between classroom management styles of the teachers and their academic optimism. In this study, three types of classroom management styles (interventionist style, interactionist style, and non-interventionist style) have been considered. Research community is all public primary school…

Classroom Management Strategies to Address the Needs of Sudanese Refugee Learners: Support Document--Methodology and Literature Review

Science.gov (United States)

Burgoyne, Ursula; Hull, Oksana

2007-01-01

This document presents the methodology and literature review for the research report "Classroom Management Strategies to Address the Needs of Sudanese Refugee Learners" (ED499673), which examined the extent to which English language, literacy and numeracy teachers used classroom management strategies to meet the needs of adult Sudanese…

Classroom management at the university level: lessons from a former high school earth science teacher

Science.gov (United States)

Lazar, C.

2009-12-01

Just a few days before my career as a fledgling science teacher began in a large public high school in New York City, a mentor suggested I might get some ideas about how to run a classroom from a book called The First Days Of School by Harry Wong. Although the book seemed to concentrate more on elementary students, I found that many of the principles in the book worked well for high school students. Even as I have begun to teach at the university level, many of Wong’s themes have persisted in my teaching style. Wong’s central thesis is that for learning to occur, a teacher must create the proper environment. In education jargon, a good climate for learning is generated via classroom management, an array of methods used by elementary and secondary school teachers to provide structure and routine to a class period via a seamless flow of complementary activities. Many college professors would likely consider classroom management to be chiefly a set of rules to maintain discipline and order among an otherwise unruly herd of schoolchildren, and therefore not a useful concept for mature university students. However, classroom management is much deeper than mere rules for behavior; it is an approach to instructional design that considers the classroom experience holistically. A typical professorial management style is to lecture for an hour or so and ask students to demonstrate learning via examinations several times in a semester. In contrast, a good high school teacher will manage a class from bell-to-bell to create a natural order and flow to a given lesson. In this presentation, I will argue for an approach to college lesson design similar to the classroom management style commonly employed by high school and elementary school teachers. I will suggest some simple, practical techniques learned during my high school experience that work just as well in college: warm-up and practice problems, time management, group activities, bulletin boards, learning environment

Dairy cows welfare quality in tie-stall housing system with or without access to exercise

Science.gov (United States)

2013-01-01

tie-stall farms which allow exercise for cows (paddocks, pasture or both) than in those which do not. In the light of our results we consider that dairy cattle welfare is not necessarily poor in tie-stall housing systems, its quality depending on the management practices. PMID:23724804

Combustion-Powered Actuation for Dynamic Stall Suppression - Simulations and Low-Mach Experiments

Science.gov (United States)

Matalanis, Claude G.; Min, Byung-Young; Bowles, Patrick O.; Jee, Solkeun; Wake, Brian E.; Crittenden, Tom; Woo, George; Glezer, Ari

2014-01-01

An investigation on dynamic-stall suppression capabilities of combustion-powered actuation (COMPACT) applied to a tabbed VR-12 airfoil is presented. In the first section, results from computational fluid dynamics (CFD) simulations carried out at Mach numbers from 0.3 to 0.5 are presented. Several geometric parameters are varied including the slot chordwise location and angle. Actuation pulse amplitude, frequency, and timing are also varied. The simulations suggest that cycle-averaged lift increases of approximately 4% and 8% with respect to the baseline airfoil are possible at Mach numbers of 0.4 and 0.3 for deep and near-deep dynamic-stall conditions. In the second section, static-stall results from low-speed wind-tunnel experiments are presented. Low-speed experiments and high-speed CFD suggest that slots oriented tangential to the airfoil surface produce stronger benefits than slots oriented normal to the chordline. Low-speed experiments confirm that chordwise slot locations suitable for Mach 0.3-0.4 stall suppression (based on CFD) will also be effective at lower Mach numbers.

Effect of artificial UV irradiation on spore content of stall air and fattening pig breeding

International Nuclear Information System (INIS)

Kalich, J.; Blendl, H.M.

1978-01-01

The influence of a continuous UV irradiation (emitter NN 33/89 original Hanau) during the fattening periods primarily in the bactericide region of 253.7 nm of various intensities on the spore content of air, on the state of health and on the fattening breeding of pigs was tested in two fattening procedures. The high spore number per m 3 air of over 700 000 upon occupying the stall in the first fattening procedure was reduced by 90.5% to about 70 000 after 1 week of UV irradiation, and in the second procedure, from 111 500 to 16 000, i.e. a reduction of 85.5%. The spore content of the stall air then exhibited large deviations reducing and increasing. The same deviations were recorded for dust content. There was no absolute correlation between dust and spore content of the air until the 11th week after starting UV irradiation in either test. The spore content sank in the reference stalls also without UV irradiation, by 29.9% in the first fattening procedure 1 week after occupying the stall and even by 75% in the second procedure. The spore content of the air in the reference stalls also then exhibited deviations sinking and rising as in the test stalls with UV irradiation. Here too, there was no correlation between dust and spore content of the air. The spore content in the air was 2 to 7 times higher in the reference stalls than in the test stalls. One may conclude from the tests that the promoting irradiation strength is between 15 and 20 μW/cm 2 and that short-term stool production in danish stalling, 60 μW/cm 2 are not harmful. Air disinfection with UV irradiation, can only be part of the total hygiene measures taken in veterinary medicine and may only be considered as an important link in the chain of the health promoting and increased efficient hygiene measures in the intensification of aggriculturally useful animals. (orig./AJ) [de

Do United States’ Teachers Know and Adhere to the National Guidelines on Asthma Management in the Classroom? A Systematic Review

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Yudilyn Jaramillo

2015-01-01

Full Text Available Proper asthma management in schools is important in achieving optimum asthma control in children with asthma. The National Heart, Lung, and Blood Institute (NHLBI has developed guidelines on classroom asthma management. We conducted a systematic review to examine teacher knowledge of the NHLBI guidelines on asthma management in the classroom. We searched PubMed and EMBASE using search terms “asthma management,” “teacher(s,” “school teacher,” and “public school.” The inclusion criteria were articles published in English from 1994 to May 2014 that focus on schools in the United States (US. From 535 titles and abstracts, 9 studies met inclusion criteria. All studies reported that school teachers did not know the policies and procedures of asthma management. Teachers relied on school nurses to handle medical emergencies. Some studies identified that lack of full-time school nurses was a barrier to asthma management. Only one study showed directly that classroom teachers were not following the NHLBI guidelines on asthma management. Our literature review revealed that US teachers do not know the NHLBI guidelines on asthma management in the classroom. Future research should focus on interventions targeted toward training classroom teachers on asthma management as per NHLBI guidelines to ultimately improve asthma management in schools.

Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

Energy Technology Data Exchange (ETDEWEB)

Guntur, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schreck, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sorensen, N. N. [Technical Univ. of Denmark, Lyngby (Denmark); Bergami, L. [Technical Univ. of Denmark, Lyngby (Denmark)

2015-04-22

It is well known that airfoils under unsteady flow conditions with a periodically varying angle of attack exhibit aerodynamic characteristics different from those under steady flow conditions, a phenomenon commonly known as dynamic stall. It is also well known that the steady aerodynamic characteristics of airfoils in the inboard region of a rotating blade differ from those under steady two-dimensional (2D) flow conditions, a phenomenon commonly known as rotational augmentation. This paper presents an investigation of these two phenomena together in the inboard parts of wind turbine blades. This analysis is carried out using data from three sources: (1) the National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation, (2) data from unsteady Delayed Detached Eddy Simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D, and (3) data from a simplified model based on the blade element momentum method with a dynamic stall subroutine that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional 2D nonrotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared to three select cases of the N sequence experimental data, which serves as a validation of the DDES method. Results show reasonable agreement between the two data in two out of three cases studied. Second, the dynamic time series of the lift and the moment polars obtained from the experiments are compared to those from the dynamic stall subroutine that uses the rotationally augmented steady polars. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in 2D flow to be

Managing bereavement in the classroom: a conspiracy of silence?

Science.gov (United States)

Lowton, Karen; Higginson, Irene J

2003-10-01

The ways in which teachers in British schools manage bereaved children are underreported. This article reports the impact of students' bereavement and their subsequent management in primary and secondary school classrooms in Southeast London. Thirteen school staff working in inner-city schools took part in in-depth interviews that focused on the impact of bereaved children on the school and how teachers responded to these children.All respondents had previously had contact with a local child bereavement service that aims to provide support, advice, and consultancy to children, their parents, and teachers. Interviews were audiotaped, transcribed verbatim, and analyzed using ATLAS-ti. Three main themes were identified from analysis of interview data. Firstly, British society, culture, local communities, and the family were significant influences in these teachers' involvement with bereaved students. Secondly, school staff managed bereaved students through contact with other adults and using practical classroom measures such as "time out" cards and contact books. Lastly, teachers felt they had to be strong, even when they were distressed. Surprise was expressed at the mature reaction of secondary school students to deaths of others. The article recommends that future research needs to concentrate on finding the most effective way of supporting routinely bereaved children, their families, and teachers.

The Case for Individualizing Behavior Management Approaches in Inclusive Classrooms

Science.gov (United States)

Grossman, Herbert

2005-01-01

In today's heterogeneous classrooms, one-method-fits-all-students behavior management approaches are ineffective and often harmful. To succeed with all of their students, teachers should determine whether students have emotional disorders, conduct/behavior disorders, robust male-typical behavior patterns, culturally influenced behavior, learning…

Teaching Styles of the Classroom Managers in one Basic Primary School in the Philippines

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Marife G.Villena

2015-05-01

Full Text Available This study aimed to determine the teaching styles of the classroom managers in Pinamucan Elementary School. Specifically, it identified the demographic profile or the teachers respondents in terms of age, gender, educational qualification, number of seminars attended, assigned level and years of services; and find out which of the teaching styles of the teacher respondents in terms of whole class, individual, and small group activities are practiced. The study used descriptive methods were a standardized questionnaire was utilized as the main instrument in gathering data. Based on the result, Most of the classroom managers belonged to the middle aged bracket; had been working from 20 to 29 years in this institution, and were assigned in different grades / levels, and had attended 7-9 seminars for the length of time they had served there; majority of the respondents often use the question and answer method when doing whole class activities. For individual activities, homework is often used by the classroom managers to get their students’ attention while for small group activities, games were often practiced as means of initiating cooperation among students. The school may be practice the used of LCD. School administrator mat conduct seminars regarding modern classroom methodologies

Study and Control of a Radial Vaned Diffuser Stall

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Aurélien Marsan

2012-01-01

Full Text Available The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

Teachers' Facility with Evidence-Based Classroom Management Practices: An Investigation of Teachers' Preparation Programmes and In-Service Conditions

Science.gov (United States)

Ficarra, Laura; Quinn, Kevin

2014-01-01

In the present investigation, teachers' self-reported knowledge and competency ratings for the evidence-based classroom management practices were analysed. Teachers also reflected on how they learned evidence-based classroom management practices. Results suggest that teachers working in schools that implement Positive Behavioural Interventions and…

Development of a Computerized In-Basket Exercise for the Classroom: A Sales Management Example

Science.gov (United States)

Pearson, Michael M.; Barnes, John W.; Onken, Marina H.

2006-01-01

This article follows the development of a sales management in-basket exercise for use in the classroom. The authors have computerized the exercise and added features to allow for additional and more quantitative input from the students. The exercise has evolved and been tested in numerous classroom situations. The computerized in-basket exercise…

Analysis of Low-Speed Stall Aerodynamics of a Business Jets Wing Using STAR-CCM+

Science.gov (United States)

Bui, Trong

2016-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted: to study the low-speed stall aerodynamics of a GIII aircrafts swept wing modified with (1) a laminar-flow wing glove, or (2) a seamless flap. The stall aerodynamics of these two different wing configurations were analyzed and compared with the unmodified baseline wing for low-speed flight. The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First AIAA CFD High-Lift Prediction Workshop.

On the relationship between EFL teachers’ classroom management approaches and the dominant teaching style: A mixed method study

Directory of Open Access Journals (Sweden)

Ali Kazemi

2016-07-01

Full Text Available As a factor contributing to a successful teaching career, classroom management can be affected by many latent and explicit variables. In this mixed method study, the researchers sought to scrutinize the possible connections among EFL teachers' classroom management approaches at two dimensions of behavior management and instructional management and the dominant teaching style. To this end, the researchers administered the Behavior and Instructional Management Scale (BIMS by Martin and Sass (2010 and the Teaching Style Inventory (TSI by Grasha (1996 to 103 randomly selected EFL teachers working at private language learning centers. Following the quantitative phase of the study, semi- structured interview sessions were held to gain more in-depth understanding of the research problems. Descriptive statistics, Pearson moment correlational analyses, regression analyses and theme analyses were implemented to analyze the data. The results of the study showed that Iranian EFL teachers followed interventionist or controlling classroom management approaches (at both dimensions of behavior and instructional management and predominantly use the formal authority teaching style. Moreover, their teaching style(s significantly correlated with both behavior management and instructional management. The findings of this study have important implications for practicing teachers, teachers in training and teacher trainers. Practicing teachers need to examine their own classroom management approaches and teaching styles to see whether these practices are conducive to successful language learning.

Nonlinear control of rotating stall and surge with axisymmetric bleed and air injection on axial flow compressors

Science.gov (United States)

Yeung, Chung-Hei (Simon)

The study of compressor instabilities in gas turbine engines has received much attention in recent years. In particular, rotating stall and surge are major causes of problems ranging from component stress and lifespan reduction to engine explosion. In this thesis, modeling and control of rotating stall and surge using bleed valve and air injection is studied and validated on a low speed, single stage, axial compressor at Caltech. Bleed valve control of stall is achieved only when the compressor characteristic is actuated, due to the fast growth rate of the stall cell compared to the rate limit of the valve. Furthermore, experimental results show that the actuator rate requirement for stall control is reduced by a factor of fourteen via compressor characteristic actuation. Analytical expressions based on low order models (2--3 states) and a high fidelity simulation (37 states) tool are developed to estimate the minimum rate requirement of a bleed valve for control of stall. A comparison of the tools to experiments show a good qualitative agreement, with increasing quantitative accuracy as the complexity of the underlying model increases. Air injection control of stall and surge is also investigated. Simultaneous control of stall and surge is achieved using axisymmetric air injection. Three cases with different injector back pressure are studied. Surge control via binary air injection is achieved in all three cases. Simultaneous stall and surge control is achieved for two of the cases, but is not achieved for the lowest authority case. This is consistent with previous results for control of stall with axisymmetric air injection without a plenum attached. Non-axisymmetric air injection control of stall and surge is also studied. Three existing control algorithms found in literature are modeled and analyzed. A three-state model is obtained for each algorithm. For two cases, conditions for linear stability and bifurcation criticality on control of rotating stall are

Development of tooling suitable for stall regulated blades

Energy Technology Data Exchange (ETDEWEB)

Hancock, M.

2001-07-01

The objectives of the project were to make significant improvements in the production of stall regulated blades in the areas of (a) the tip box, its housing, its mechanism and small GRP parts; (b) mould technology; (c) resins and glues and (d) root tooling. Although wood composite had been identified as a competitive technology for blades, compared with GRP blades, production volumes had been lower; reasons are given. The way in which the four areas identified for investigation were tackled are discussed. The study showed that the mould cycle time can be reduced to two days for a stall regulated blade and the blade quality can be improved by using the composite tip box and new resins. The time required for replication of moulds can be reduced by 40%.

Etched Impressions: Student Writing as Engaged Pedagogy in the Graduate Sport Management Classroom

Science.gov (United States)

Veri, Maria J.; Barton, Kenny; Burgee, David; Davis, James A., Jr.; Eaton, Pamela; Frazier, Cathy; Gray, Stevie; Halsey, Christine; Thurman, Richard

2006-01-01

This article illustrates the pedagogical value of employing student narrative writing assignments in the graduate sport management classroom and advocates for cultural studies and critical pedagogy approaches to teaching sport management. The article considers students' autobiographical narratives within a theoretical framework of cultural…

The Incredible Years Teacher Classroom Management Program: Using Coaching to Support Generalization to Real-World Classroom Settings

Science.gov (United States)

Reinke, Wendy M.; Stormont, Melissa; Webster-Stratton, Carolyn; Newcomer, Lori L.; Herman, Keith C.

2012-01-01

This article focuses on the Incredible Years Teacher Classroom Management Training (IY TCM) intervention as an example of an evidence-based program that embeds coaching within its design. First, the core features of the IY TCM program are described. Second, the IY TCM coaching model and processes utilized to facilitate high fidelity of…

Gender in the Management Education Classroom: A Collaborative Learning Journey

Science.gov (United States)

Bilimoria, Diana; O'Neil, Deborah A.; Hopkins, Margaret M.; Murphy, Verena

2010-01-01

In this article, the authors describe a classroom incident and their subsequent learnings about effectively managing issues of gender diversity in an MBA course titled "Women in Organizations." The authors employ Kolb's learning cycle as a framework for describing the incident ("concrete experience"), reflecting on and discussing what occurred…

Transformational Leadership: Practicing What We Teach in the Management Classroom

Science.gov (United States)

Pounder, James S.

2008-01-01

In a Hong Kong study, the author examined the effect on undergraduate business students of university business school instructors' exhibiting a transformational leadership style in the classroom. Transformational leadership is one of the central concepts in management, and research has indicated that a positive association exists between this…

Value driven classroom management-the congruence between the preferred and the democratic values

Directory of Open Access Journals (Sweden)

Fatma Özmen

2013-11-01

Full Text Available The rapid changes in all areas of communities have raised the level of concerns about weakening of the societal values. And many academics and researchers have begun to become interested in the issues for placing especially the democratic values in education more than ever before, in order to constitute more livable social environments. The goal of this study is, on the basis of gender variable, to determine what values have driven the teachers in their classroom management practices, and to find out if these values are congruent with the democratic principles. The research group comprises 68 teachers working in Regional Public Boarding Schools. The teachers were asked to list the most and the least preferred values in classroom management from a predetermined value list. The analysis of the data revealed that the most desired 10 values used by teachers in classroom management practices were generally common between female and male gender groups and both groups’ preferences indicated similar results. ‘Honesty’ and ‘responsibility’ take at the top of the most preferred value list. However, the value of ‘equality’ which is indispensible for maintaining democracyin classroom, was preferred by less than half of the teachers. And the values such as peace, freedom, social recognition and the like were not given place in the most preferred value list. The least preferred ten values were generally the ones which were not directly related to democracy. These results indicate that some essential values related to democracy are not given much importance. It is recommended that teachers should be trained well about creating democratic classroom settings especially in pre-service education. And, school leaders should give utmost importance to constitute a democratic school environment; and school wide practices should be congruent with democratic principles so as to form it as a life style.

Internal Flow of a High Specific-Speed Diagonal-Flow Fan (Rotor Outlet Flow Fields with Rotating Stall

Directory of Open Access Journals (Sweden)

Norimasa Shiomi

2003-01-01

Full Text Available We carried out investigations for the purpose of clarifying the rotor outlet flow fields with rotating stall cell in a diagonal-flow fan. The test fan was a high–specific-speed (ns=1620 type of diagonal-flow fan that had 6 rotor blades and 11 stator blades. It has been shown that the number of the stall cell is 1, and its propagating speed is approximately 80% of its rotor speed, although little has been known about the behavior of the stall cell because a flow field with a rotating stall cell is essentially unsteady. In order to capture the behavior of the stall cell at the rotor outlet flow fields, hot-wire surveys were performed using a single-slant hotwire probe. The data obtained by these surveys were processed by means of a double phase-locked averaging technique, which enabled us to capture the flow field with the rotating stall cell in the reference coordinate system fixed to the rotor. As a result, time-dependent ensemble averages of the three-dimensional velocity components at the rotor outlet flow fields were obtained. The behavior of the stall cell was shown for each velocity component, and the flow patterns on the meridional planes were illustrated.

Conical Magnetic Bearings Developed for Active Stall Control in Gas Turbine Engines

Science.gov (United States)

Trudell, Jeffrey J.; Kascak, Albert F.; Provenza, Andrew J.; Buccieri, Carl J.

2004-01-01

Active stall control is a current research area at the NASA Glenn Research Center that offers a great benefit in specific fuel consumption by allowing the gas turbine to operate beyond the onset of stall. Magnetic bearings are being investigated as a new method to perform active stall control. This enabling global aviation safety technology would result in improved fuel efficiency and decreased carbon dioxide emissions, as well as improve safety and reliability by eliminating oil-related delays and failures of engine components, which account for 40 percent of the commercial aircraft departure delays. Active stall control works by perturbing the flow in front of the compressor stage such that it cancels the pressure wave, which causes the compressor to go into stall. Radial magnetic bearings are able to whirl the shaft so that variations in blade tip leakage would flow upstream causing a perturbation wave that could cancel the rotating stall cell. Axial or thrust magnetic bearings cannot be used to cancel the surge mode in the compressor because they have a very low bandwidth and thus cannot modulate at a high enough frequency. Frequency response is limited because the thrust runner cannot be laminated. To improve the bandwidth of magnetic thrust bearings, researchers must use laminations to suppress the eddy currents. A conical magnetic bearing can be laminated, resulting in increased bandwidth in the axial direction. In addition, this design can produce both radial and thrust force in a single bearing, simplifying the installation. The proposed solution combines the radial and thrust bearing into one design that can be laminated--a conical magnetic bearing. The new conical magnetic bearing test rig, funded by a Glenn fiscal year 2002 Director's Discretionary Fund, was needed because none of the existing rigs has an axial degree of freedom. The rotor bearing configuration will simulate that of the main shaft on a gas turbine engine. One conical magnetic bearing

Managing Learning Experiences in an AACSB Environment: Beyond the Classroom

Science.gov (United States)

Spruell, James; Hawkins, Al; Vicknair, David

2009-01-01

The study explores the development and management of a rich learning environment that extends the traditional classroom to include significant co-curricular programs. Learning enrichment is guided by the individual mission of the business school, accreditation agency (AACSB), and in our case, the Jesuit mission. That central framework provides a…

A Review of Literature on Teacher Efficacy and Classroom Management

Science.gov (United States)

Dibapile, Waitshega Tefo Smitta

2012-01-01

The purpose of this paper was to review the literature on teacher efficacy and classroom management. The conceptual framework of this paper was based on the theories of Rotter (1966) and Bandura (1977). The review of literature indicated that teacher efficacy helps teachers plan effective instructional strategies, increases performance, and…

A dynamic stall model for airfoils with deformable trailing edges

DEFF Research Database (Denmark)

Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Dan Christian

2007-01-01

on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa [4], which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed......The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. [7]. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments...

Teaching Management and Implementation of Pedagogical Classroom Projects in Basic Education

Directory of Open Access Journals (Sweden)

Waldemar Antonio Guerrero Matos

2006-11-01

Full Text Available The present article diffuses the results of the oriented study to determine the relationship between the administration of the educational one and the execution of the pedagogic projects of classroom in Basic Education. Theoretically it was based on the constructivismo and the contributions of the National Basic Curriculum. The investigation type was descriptive. The results allowed to corroborate in the teachers, weaknesses in the execution of the Pedagogic Projects of Classroom, evidencing difficulties to the moment to apply the pedagogic abilities. Therefore it is recommended to carry out courses of upgrade to manage with effectiveness this strategy of planning constructivist.

A time-varying subjective quality model for mobile streaming videos with stalling events

Science.gov (United States)

Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

2015-09-01

Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

Analysis of compressible light dynamic stall flow at transitional Reynolds numbers

DEFF Research Database (Denmark)

Dyken, R.D. Van; Ekaterinaris, John A.; Chandrasekhara, M.S.

1996-01-01

Numerical and experimental results of steady and light dynamic stall flow over an oscillating NACA 0012 airfoil at a freestream Mach number of 0.3 and Reynolds number of 0.54 x 10(6) are compared, The experimental observation that dynamic stall is induced from the bursting of a laminar separation...... point is specified suitably and a simple transition length model is incorporated to determine the extent of the laminar separation bubble. The thin-layer approximations of compressible, Reynolds-averaged, Navier-Stokes equations are used for the numerical solution, with an implicit, upwind-biased, third...

Teachers' Emotional Labour, Discrete Emotions, and Classroom Management Self-Efficacy

Science.gov (United States)

Lee, Mikyoung; van Vlack, Stephen

2018-01-01

Extending research on teachers' emotions beyond general educational contexts and Western samples, we examined how teachers' emotions correlated with their emotional labour strategies and classroom management self-efficacy with an East-Asian sample in an English teaching context (127 Korean English teachers). Surface acting (emotional expressions…

The Implementation of a Positive Behaviour Management Programme in a Primary Classroom: A Case Study.

Science.gov (United States)

Atherley, Carole

1990-01-01

Positive behavior management has been recommended as a more acceptable form of classroom management than traditional behavioral modification. This paper discusses the application of stimulus and contingency control methods (positive behavior management) to elicit more socially and academically acceptable behavior from elementary school children.…

The computation of the post-stall behavior of a circulation controlled airfoil

Science.gov (United States)

Linton, Samuel W.

1993-01-01

The physics of the circulation controlled airfoil is complex and poorly understood, particularly with regards to jet stall, which is the eventual breakdown of lift augmentation by the jet at some sufficiently high blowing rate. The present paper describes the numerical simulation of stalled and unstalled flows over a two-dimensional circulation controlled airfoil using a fully implicit Navier-Stokes code, and the comparison with experimental results. Mach numbers of 0.3 and 0.5 and jet total to freestream pressure ratios of 1.4 and 1.8 are investigated. The Baldwin-Lomax and k-epsilon turbulence models are used, each modified to include the effect of strong streamline curvature. The numerical solutions of the post-stall circulation controlled airfoil show a highly regular unsteady periodic flowfield. This is the result of an alternation between adverse pressure gradient and shock induced separation of the boundary layer on the airfoil trailing edge.

Parametric analyses on dynamic stall control of rotor airfoil via synthetic jet

Directory of Open Access Journals (Sweden)

Qijun ZHAO

2017-12-01

Full Text Available The effects of synthetic jet control on unsteady dynamic stall over rotor airfoil are investigated numerically. A moving-embedded grid method and an Unsteady Reynolds Averaged Navier-Stokes (URANS solver coupled with k-ω Shear Stress Transport (SST turbulence model are established for predicting the complex flowfields of oscillatory airfoil under jet control. Additionally, a velocity boundary condition modeled by sinusoidal function has been developed to fulfill the perturbation effect of periodic jet. The validity of present CFD method is evaluated by comparisons of the calculated results of baseline dynamic stall case for rotor airfoil and jet control case for VR-7B airfoil with experimental data. Then, parametric analyses are conducted emphatically for an OA212 rotor airfoil to investigate the effects of jet control parameters (jet location, dimensionless frequency, momentum coefficient, jet angle, jet type and dual-jet on dynamic stall characteristics of rotor airfoil. It is demonstrated by the calculated results that efficiency of jet control could be improved with specific momentum coefficient and jet angle when the jet is located near separation point of rotor airfoil. Furthermore, the dual-jet could improve control efficiency more obviously on dynamic stall of rotor airfoil with respect to the unique jet, and the influence laws of dual-jet’s angles and momentum coefficients on control effects are similar to those of the unique jet. Finally, unsteady aerodynamic characteristics of rotor via synthetic jet which is located on the upper surface of rotor blade in forward flight are calculated, and as a result, the aerodynamic characteristics of rotor are improved compared with the baseline. The results indicate that synthetic jet has the capability in improving aerodynamic characteristics of rotor. Keywords: Airfoil, Dynamic stall characteristics, Flow control, Moving-embedded grid methodology, Navier-Stokes equations, Parametric

Project Termination Report. Title IV-C Classroom Management Project. ESEA Title IV-C, August 29, 1981 - September 30, 1982.

Science.gov (United States)

Halasa, Ofelia; Theus, Frank

This report provides a summary description of the Title IV-C Classroom Management Project conducted in the Cleveland (Ohio) Public Schools. The purpose of this project was to develop and pilot test a resource handbook designed to improve elementary and secondary school teachers' ability to organize and manage their classrooms. The development of…

Time Accurate Unsteady Simulation of the Stall Inception Process in the Compression System of a US Army Helicopter Gas Turbine Engine

National Research Council Canada - National Science Library

Hathaway, Michael D; Herrick, Greg; Chen, Jenping; Webster, Robert

2004-01-01

.... Improved understanding of the stall inception process and how stall control technologies mitigate such will provide compressors with increased tolerance to stall, thereby expanding the operational...

The impact of Flipped Classroom on the motivation and learning of students in Operations Management

Directory of Open Access Journals (Sweden)

Eloísa Díaz Garrido

2017-06-01

Full Text Available The objective of this work is to analyze the effectiveness of the Flipped Classroom methodology in the discipline of Operations Management, analyzing for this the motivation of the students and their learning results in terms of the acquisition of skills and qualifications obtained. Specifically, a comparative analysis is carried out with two teaching groups, having applied the methodology of Flipped Classroom only in one of them. -------------- El impacto del flipped classroom en la motivación y en el aprendizaje de los estudiantes en la asignatura Dirección de Operaciones

Aerodynamic shape optimization for alleviating dynamic stall characteristics of helicopter rotor airfoil

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Wang Qing

2015-04-01

Full Text Available In order to alleviate the dynamic stall effects in helicopter rotor, the sequential quadratic programming (SQP method is employed to optimize the characteristics of airfoil under dynamic stall conditions based on the SC1095 airfoil. The geometry of airfoil is parameterized by the class-shape-transformation (CST method, and the C-topology body-fitted mesh is then automatically generated around the airfoil by solving the Poisson equations. Based on the grid generation technology, the unsteady Reynolds-averaged Navier-Stokes (RANS equations are chosen as the governing equations for predicting airfoil flow field and the highly-efficient implicit scheme of lower–upper symmetric Gauss–Seidel (LU-SGS is adopted for temporal discretization. To capture the dynamic stall phenomenon of the rotor more accurately, the Spalart–Allmaras turbulence model is employed to close the RANS equations. The optimized airfoil with a larger leading edge radius and camber is obtained. The leading edge vortex and trailing edge separation of the optimized airfoil under unsteady conditions are obviously weakened, and the dynamic stall characteristics of optimized airfoil at different Mach numbers, reduced frequencies and angles of attack are also obviously improved compared with the baseline SC1095 airfoil. It is demonstrated that the optimized method is effective and the optimized airfoil is suitable as the helicopter rotor airfoil.

Teaching Supply Chain Management Complexities: A SCOR Model Based Classroom Simulation

Science.gov (United States)

Webb, G. Scott; Thomas, Stephanie P.; Liao-Troth, Sara

2014-01-01

The SCOR (Supply Chain Operations Reference) Model Supply Chain Classroom Simulation is an in-class experiential learning activity that helps students develop a holistic understanding of the processes and challenges of supply chain management. The simulation has broader learning objectives than other supply chain related activities such as the…

Classroom Management Skills of The Language Teachers

Directory of Open Access Journals (Sweden)

Arif Sarıçoban

2005-04-01

Full Text Available Teachers or educators, most of the time, concentrate on the theoretical aspects oflanguage teaching and study them as much as possible. However, in practice, we start thinkingthat we will have to keep a number of people together in the same place. These are often thepeople who come from many different backgrounds and whose expectations differ. In thiscase, it becomes more and more difficult to appeal to every individual in class. Therefore, asteachers we should initially be trained on how to manage our classrooms and how to providethe necessary environment to put into practice the things we have learned to teach a language.Obviously, we need management skills as well as the language teaching skill. Actually, it isnot as difficult as many people think. As teachers if we fulfill our duties properly, a wellmanagedclass will ensue. In this study, therefore, the definition of class management isregarded roughly “to keep people from different environments directed to one single goal”.When this is accomplished, we are unlikely to live discipline problems.

The Impact of Years of Teaching Experience on the Classroom Management Approaches of Elementary School Teachers

Science.gov (United States)

Unal, Zafer; Unal, Aslihan

2012-01-01

This study provided a basis for answering the following essential question: Does the years of experience affect teachers' classroom management approaches? Data were collected from 268 primary school teachers. The findings of this study demonstrated that experienced teachers are more likely to prefer to be in control in their classrooms than…

Dynamic stall - The case of the vertical axis wind turbine

Science.gov (United States)

Laneville, A.; Vittecoq, P.

1986-05-01

This paper presents the results of an experimental investigation on a driven Darrieus turbine rotating at different tip speed ratios. For a Reynolds number of 3.8 x 10 to the 4th, the results indicate the presence of dynamic stall at tip speed ratio less than 4, and that helicopter blade aerodynamics can be used in order to explain some aspects of the phenomenon. It was observed that in deep stall conditions, a vortex is formed at the leading edge; this vortex moves over the airfoil surface with 1/3 of the airfoil speed and then is shed at the trailing edge. After its shedding, the vortex can interact with the airfoil surface as the blade passes downstream.

DYNSTALL: Subroutine package with a dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, Anders [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

2001-03-01

A subroutine package, called DYNSTALL, for the calculation of 2D unsteady airfoil aerodynamics is described. The subroutines are written in FORTRAN. DYNSTALL is basically an implementation of the Beddoes-Leishman dynamic stall model. This model is a semi-empirical model for dynamic stall. It includes, however, also models for attached flow unsteady aerodynamics. It is complete in the sense that it treats attached flow as well as separated flow. Semi-empirical means that the model relies on empirically determined constants. Semi because the constants are constants in equations with some physical interpretation. It requires the input of 2D airfoil aerodynamic data via tables as function of angle of attack. The method is intended for use in an aeroelastic code with the aerodynamics solved by blade/element method. DYNSTALL was written to work for any 2D angles of attack relative to the airfoil, e.g. flow from the rear of an airfoil.

Origin of the Species: An Epistemological Tale of Classroom Management Theory and the Evolution of a Teacher Preparation Course Syllabus

Science.gov (United States)

Hertel, Nichole L.

2012-01-01

This dissertation dually explores the topics of classroom management theory as it occurs in teacher preparation programs in American colleges of education and of curriculum syllabus design of undergraduate education classes teaching such. It begins with the classroom management and teaching pedagogical knowledges gained through my experience as a…

Increasing On-Task Behavior in Students in a Regular Classroom: Effectiveness of a Self-Management Procedure Using a Tactile Prompt

Science.gov (United States)

Moore, Dennis W.; Anderson, Angelika; Glassenbury, Michele; Lang, Russell; Didden, Robert

2013-01-01

Self-management strategies have been shown to be widely effective. However, limited classroom-based research exists involving low performing but developmentally normal high school-aged participants. This study examined the effectiveness of a self-management strategy aimed at increasing on-task behavior in general education classrooms with students…

Dynamic Stall Vortex Formation of OA-209 Airfoil at Low Reynolds Number

OpenAIRE

Aung Myo Thu; Sang Eon Jeon; Yung Hwan Byun; Soo Hyung Park

2014-01-01

The unsteady flow field around oscillating OA-209 airfoil at a Reynolds number of 3.5×105 were investigated. Three different reduced frequencies were tested in order to see how it affects the hysteresis loop of an airfoil. At a reduced frequency of 0.05 the deep dynamic stall phenomenon was observed. Lift overshooting was observed as a result of dynamic stall vortex (DSV) shedding. Further investigation was carried out to find out the cause of DSV formation and shedding over airfoil. Particle...

Characterization of mathematics instructional practises for prospective elementary teachers with varying levels of self-efficacy in classroom management and mathematics teaching

Science.gov (United States)

Lee, Carrie W.; Walkowiak, Temple A.; Nietfeld, John L.

2017-03-01

The purpose of this study was to investigate the relationship between prospective teachers' (PTs) instructional practises and their efficacy beliefs in classroom management and mathematics teaching. A sequential, explanatory mixed-methods design was employed. Results from efficacy surveys, implemented with 54 PTs were linked to a sample of teachers' instructional practises during the qualitative phase. In this phase, video-recorded lessons were analysed based on tasks, representations, discourse, and classroom management. Findings indicate that PTs with higher levels of mathematics teaching efficacy taught lessons characterised by tasks of higher cognitive demand, extended student explanations, student-to-student discourse, and explicit connections between representations. Classroom management efficacy seems to bear influence on the utilised grouping structures. These findings support explicit attention to PTs' mathematics teaching and classroom management efficacy throughout teacher preparation and a need for formative feedback to inform development of beliefs about teaching practises.

The Film as Visual Aided Learning Tool in Classroom Management Course

Science.gov (United States)

Altinay Gazi, Zehra; Altinay Aksal, Fahriye

2011-01-01

This research aims to investigate the impact of the visual aided learning on pre-service teachers' co-construction of subject matter knowledge in teaching practice. The study revealed the examination of film as an active cognizing and learning tool in classroom management course within teacher education programme. Within the framework of action…

Flight Measurements of the Flying Qualities of a Lockheed P-80A Airplane (Army No. 44-85099) - Stalling Characteristics

Science.gov (United States)

Anderson, Seth B.; Cooper, George E.

1947-01-01

This report contains the flight-test results of the stalling characteristics measured during the flying-qualities investigation of the Lockheed P-8OA airplane (Army No. 44-85099). The tests were conducted in straight and turning flight with and without wing-tip tanks. These tests showed satisfactory stalling characteristics and adequate stall warning for all configurations and conditions tested.

Classroom Management of Children with Emotional and Behavioral Disorders. A Storied Model: Torey Hayden's One Child

Science.gov (United States)

Marlowe, Mike; Disney, Gayle; Wilson, Kayce Jo

2004-01-01

Torey Hayden's style of classroom management in her nonfiction book "One Child" was examined. "One Child" unfolds within the space of a special education classroom for children with severe behavioral impairments and focuses on Sheila, a troubled 6-year-old, who has tied a 3-year-old boy to a tree and critically burned him. Each technique Hayden…

Teachers of young children (3-5 years old and their interaction with pupils: approaching positive classroom management

Directory of Open Access Journals (Sweden)

Fryni Paraskevopoulou

2006-04-01

Full Text Available This paper explores the social and emotional development of children between three to five years old, the factors that affect their in-school behaviour and strategies for positive teacher classroom management. It is suggested that teachers need to reflect upon children’s development in order for an effective classroom management to be achieved. Aspects of teachers’ expectations about interaction between children and teachers will also be exemplified. Literature research was employed as a method to explore the relevant issues.

Diagnosis of voltage collapse due to induction motor stalling using static analysis

International Nuclear Information System (INIS)

Karbalaei, F.; Kalantar, M.; Kazemi, A.

2008-01-01

Induction motor stalling is one of the important reasons for voltage collapse. This paper presents that, for induction motor stalling diagnosis, it is not necessary to use a third or first order dynamic model of induction motors. Instead, a method is presented based on algebraic calculations for which the steady state model of the induction motor considering different kinds of mechanical loads (constant and variable torque) is added to the power flow equations. Simulation results for a simple system confirm the correctness of the proposed method as compared to dynamic simulation results

Piloted Simulator Evaluation Results of Flight Physics Based Stall Recovery Guidance

Science.gov (United States)

Lombaerts, Thomas; Schuet, Stefan; Stepanyan, Vahram; Kaneshige, John; Hardy, Gordon; Shish, Kimberlee; Robinson, Peter

2018-01-01

In recent studies, it has been observed that loss of control in flight is the most frequent primary cause of accidents. A significant share of accidents in this category can be remedied by upset prevention if possible, and by upset recovery if necessary, in this order of priorities. One of the most important upsets to be recovered from is stall. Recent accidents have shown that a correct stall recovery maneuver remains a big challenge in civil aviation, partly due to a lack of pilot training. A possible strategy to support the flight crew in this demanding context is calculating a recovery guidance signal, and showing this signal in an intuitive way on one of the cockpit displays, for example by means of the flight director. Different methods for calculating the recovery signal, one based on fast model predictive control and another using an energy based approach, have been evaluated in four relevant operational scenarios by experienced commercial as well as test pilots in the Vertical Motion Simulator at NASA Ames Research Center. Evaluation results show that this approach could be able to assist the pilots in executing a correct stall recovery maneuver.

An experimental description of the flow in a centrifugal compressor from alternate stall to surge

Science.gov (United States)

Moënne-Loccoz, V.; Trébinjac, I.; Benichou, E.; Goguey, S.; Paoletti, B.; Laucher, P.

2017-08-01

The present paper gives the experimental results obtained in a centrifugal compressor stage designed and built by SAFRAN Helicopter Engines. The compressor is composed of inlet guide vanes, a backswept splittered unshrouded impeller, a splittered vaned radial diffuser and axial outlet guide vanes. Previous numerical simulations revealed a particular S-shape pressure rise characteristic at partial rotation speed and predicted an alternate flow pattern in the vaned radial diffuser at low mass flow rate. This alternate flow pattern involves two adjacent vane passages. One passage exhibits very low momentum and a low pressure recovery, whereas the adjacent passage has very high momentum in the passage inlet and diffuses efficiently. Experimental measurements confirm the S-shape of the pressure rise characteristic even if the stability limit experimentally occurs at higher mass flow than numerically predicted. At low mass flow the alternate stall pattern is confirmed thanks to the data obtained by high-frequency pressure sensors. As the compressor is throttled the path to instability has been registered and a first scenario of the surge inception is given. The compressor first experiences a steady alternate stall in the diffuser. As the mass flow decreases, the alternate stall amplifies and triggers the mild surge in the vaned diffuser. An unsteady behavior results from the interaction of the alternate stall and the mild surge. Finally, when the pressure gradient becomes too strong, the alternate stall blows away and the compressor enters into deep surge.

Effects of Teacher Consultation on Evidence-Based Classroom Management Strategies: Teacher and Student Behavior

Science.gov (United States)

Funk, Kristin M.

2013-01-01

The American Psychological Association (APA) conducted the online 2005-2006 Teacher Needs Survey wherein 52% of first year teachers, 28% of teachers with two to five years of experience, and 26% of teachers with 6 to 10 years experience ranked classroom management as their greatest need. Difficulty managing student behaviors leads to higher stress…

Comparing Beginning and Experienced Teachers' Perceptions of Classroom Management Beliefs and Practices in Elementary Schools in Turkey

Science.gov (United States)

Unal, Zafer; Unal, Aslihan

2009-01-01

The primary objective of this study was to investigate whether a difference in teachers' classroom management styles exists based on years of teaching experience. Data were collected from 282 elementary school teachers employed by 11 elementary schools in Turkey. The Attitudes and Beliefs on Classroom Control Inventory was used to collect the…

The FFA dynamic stall model. The Beddoes-Leishman dynamic stall model modified for lead-lag oscillations

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden)

1997-08-01

For calculations of the dynamics of wind turbines the inclusion of a dynamic stall model is necessary in order to obtain reliable results at high winds. For blade vibrations in the lead-lag motion the velocity relative to the blade will vary in time. In the present paper modifications to the Beddoes-Leishman model is presented in order to improve the model for calculations of cases with a varying relative velocity. Comparisons with measurement are also shown and the influence on the calculated aerodynamic damping by the modifications are investigated. (au)

Air Force Instructor Evaluation Enhancement: Effective Teaching Behaviors and Assessment Procedures

Science.gov (United States)

1989-08-01

student achievement. Journal of Educational Research, 73, 16-19. Stallings, J., & Kaskowitz, 0. (1974). Follow through classroom observation : 1972-1973...provided in a way to encourage student involvement From a review of the instructor’s media, materials and handouts, and classroom observation , raters respond...Human Resources. (ERIC Document Reproduction Service No. ED 106297) Stallings, J., & Kaskowitz. D. (1974). Follow through classroom observation evaluation

Chinese Teachers' Perceptions of Students' Classroom Misbehaviour

Science.gov (United States)

Ding, Meixia; Li, Yeping; Li, Xiaobao; Kulm, Gerald

2008-01-01

This study focuses on Chinese teachers' perceptions of students' classroom misbehaviour. A questionnaire was designed to assess teachers' general concerns about classroom management, teachers' perceptions of the most frequent and troublesome types of misbehaviour, and teachers' perceived needs for help with improving classroom management. A total…

More explicit communication after classroom-based crew resource management training: results of a pragmatic trial.

NARCIS (Netherlands)

Verbeek-van Noord, I.; Bruijne, M.C. de; Twisk, J.W.R.; Dyck, C. van; Wagner, C.

2015-01-01

Rationale, aims and objectives: Aviation-based crew resource management trainings to optimize non-technical skills among professionals are often suggested for health care as a way to increase patient safety. Our aim was to evaluate the effect of a 2-day classroom-based crew resource management (CRM)

More explicit communication after classroom-based crew resource management training: results of a pragmatic trial

NARCIS (Netherlands)

van Noord, I.; de Bruijne, M.C.; Twisk, J.W.R.; van Dyck, C.; Wagner, C.

2015-01-01

Rationale, aims and objectives Aviation-based crew resource management trainings to optimize non-technical skills among professionals are often suggested for health care as a way to increase patient safety. Our aim was to evaluate the effect of a 2-day classroom-based crew resource management (CRM)

Stalled replication forks generate a distinct mutational signature in yeast

DEFF Research Database (Denmark)

Larsen, Nicolai B.; Liberti, Sascha E.; Vogel, Ivan

2017-01-01

Proliferating cells acquire genome alterations during the act of DNA replication. This leads to mutation accumulation and somatic cell mosaicism in multicellular organisms, and is also implicated as an underlying cause of aging and tumorigenesis. The molecular mechanisms of DNA replication...... Escherichia coli Tus/Ter complex) engineered into the yeast genome. We demonstrate that transient stalling at this barrier induces a distinct pattern of genome rearrangements in the newly replicated region behind the stalled fork, which primarily consist of localized losses and duplications of DNA sequences....... These genetic alterations arise through the aberrant repair of a single-stranded DNA gap, in a process that is dependent on Exo1- and Shu1-dependent homologous recombination repair (HRR). Furthermore, aberrant processing of HRR intermediates, and elevated HRR-associated mutagenesis, is detectable in a yeast...

A Dynamic Stall Model for Airfoils with Deformable Trailing Edges

International Nuclear Information System (INIS)

Andersen, Peter Bjoern; Gaunaa, Mac; Bak, Christian; Hansen, Morten Hartvig

2007-01-01

The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa for the attached flow region and Hansen et al. The model will be compared to wind tunnel measurements from Velux described by Bak et al

Flipping the Classroom Applications to Curriculum Redesign for an Introduction to Management Course: Impact on Grades

Science.gov (United States)

Albert, Michael; Beatty, Brian J.

2014-01-01

The authors discuss the application of the flipped classroom model to the redesign of an introduction to management course at a highly diverse, urban, Association to Advance Collegiate Schools of Business-accredited U.S. university. The author assessed the impact of a flipped classroom versus a lecture class on grades. Compared to the prior…

Self- Versus Teacher Management of Behavior for Elementary School Students with Asperger Syndrome: Impact on Classroom Behavior

Science.gov (United States)

Shogren, Karrie A.; Lang, Russell; Machalicek, Wendy; Rispoli, Mandy J.; O'Reilly, Mark

2011-01-01

The purpose of this study was to evaluate and compare the effectiveness of a token economy and a self-management intervention in an inclusive kindergarten classroom. Two 5-year-old children with Asperger syndrome who were struggling to follow classroom rules participated in the study. An ABACABAC (A = baseline, B = token economy, C =…

Student Reactions to Classroom Management Technology: Learning Styles and Attitudes toward Moodle

Science.gov (United States)

Chung, Christina; Ackerman, David

2015-01-01

The authors look at student perceptions regarding the adoption and usage of Moodle. Self-efficacy theory and the Technology Acceptance Model were applied to understand student reactions to instructor implementation of classroom management software Moodle. They also looked at how the learning styles of students impacted their reactions to Moodle.…

Educators' Self-Reported Training, Use, and Perceived Effectiveness of Evidence-Based Classroom Management Practices

Science.gov (United States)

Cooper, Justin T.; Gage, Nicholas A.; Alter, Peter J.; LaPolla, Stefanie; MacSuga-Gage, Ashley S.; Scott, Terrance M.

2018-01-01

A survey study of 248 educators in four states was conducted to identify respondents' formal training, use, and perceived effectiveness of 37 evidence-based classroom management practices within four general categories: (a) antecedent-based, (b) instructionally based, (c) consequence-based, and (d) self-management. Results indicated that, on…

An insight into the separate flow and stall delay for HAWT

Energy Technology Data Exchange (ETDEWEB)

Yu, Guohua; Shen, Xin; Zhu, Xiaocheng; Du, Zhaohui [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2011-01-15

The flow characteristics and the stall delay phenomenon of wind turbine rotor due to blade rotation in the steady state non-yawed conditions are investigated. An incompressible Reynolds-averaged Navier-Stokes solver is applied to carry out all the cases at different wind speeds from 5 m/s to 10 m/s with an interval of 1 m/s. CFD results turn out to agree well with experimental ones at incoming wind speeds below 10 m/s, though at 10 m/s some deviations exist due to the relative large flow separation and 3D spanwise flow over the suction surface of the blade. In the meanwhile, a lifting surface code with and without Du-Selig stall delay model is used to predict the power. A MATLAB code is developed to extract aerodynamic force coefficients from 3D CFD computations which are compared with the 2D airfoil wind tunnel experiment to demonstrate the stall delay and augmented lift phenomenon particularly at inboard span locations of the blade. The computational results are compared with the corrected value by the Du-Selig model and a lifting surface method derived data based on the measurements of the Unsteady Aerodynamic Experiment at the NASA Ames wind tunnel. (author)

Effect of stall design on dairy calf transition to voluntary feeding on an automatic milk feeder after introduction to group housing.

Science.gov (United States)

Wilson, Tanya R; LeBlanc, Stephen J; DeVries, Trevor J; Haley, Derek B

2018-06-01

Automatic milk feeders (AMF) for young dairy calves are widely used in the dairy industry. These feeders are thought to have benefits for calf health and welfare and may reduce labor required for feeding; however, little is known about how calves adapt to feeding with AMF. The objective of this study was to observe the effects of feeding stall design on calves learning to use the AMF. The hypothesis was that solid side stalls, compared with steel bar stalls, would result in a longer latency to approach and feed from the AMF without assistance. A total of 147 Holstein calves (80 male and 67 female) were enrolled at 4 d of age, introduced to a group pen, and, at the same time, trained on an AMF. For training, calves were allowed to suck on the trainer's fingers and guided to the teat. Calves were allocated to 1 of 2 stall designs at the pen level, depending on which treatment cohort they were born into, either with steel bar stall walls (n = 46 male, 34 female calves) or with solid side stall walls (n = 34 male, 33 female calves). For 72 h after introductory training on the AMF, data from the feeders were collected and calf behavior was monitored by video. Outcomes measured included latency to first voluntary visit to the feeder and to first feeding, time spent in the feeder, amount of milk consumed over 72 h, number of retraining sessions required (retrained if linear regression models or a Poisson model for the outcome of retraining. For certain outcomes the effects of stall design interacted with difficulty of training (willingness to enter feeder and drink); for the 38% of calves that were scored as moderately difficult to train on a scale of easy, moderate, or difficult, treatment (stall design) differences were detected. These calves took 2× longer to lick or bite toward the nipple, 2× longer to first voluntarily feeding, and consumed less milk over 72 h following training when trained on the steel bar stall design. These results suggest simple features of a

Development and Construct Validation of a Situational Judgment Test of Strategic Knowledge of Classroom Management in Elementary Schools

Science.gov (United States)

Gold, Bernadette; Holodynski, Manfred

2015-01-01

The current study describes the development and construct validation of a situational judgment test for assessing the strategic knowledge of classroom management in elementary schools. Classroom scenarios and accompanying courses of action were constructed, of which 17 experts confirmed the content validity. A pilot study and a cross-validation…

Effect of free stall surface on daily activity patterns in dairy cows with relevance to lameness prevalence.

Science.gov (United States)

Cook, N B; Bennett, T B; Nordlund, K V

2004-09-01

Differences in behavior of nonlame cows, slightly lame cows, and moderately lame cows in 6 free stall barns with sand bedding (SAND) vs. 6 free stall barns with rubber-crumb geotextile mattress surfaces (MAT) were documented in Wisconsin dairy herds. All lactating cows in the 12 herds were observed and given a locomotion score based on a 4-point scale: 1 = nonlame, 2 = slightly lame, 3 = moderately lame, and 4 = severely lame. Herd least square means +/-SE for prevalence of clinical lameness (locomotion scores = 3 and 4) were 11.1 vs. 24.0 +/- 1.7% for herds using SAND vs. MAT surfaces, respectively. Subsets of 10 cows per herd with locomotion scores of 1 to 3 were observed via video cameras for 24-h periods. Cows in MAT herds spent more time standing in free stalls per day than cows in SAND herds. Differences in standing times were 0.73 h/d for cows that were not lame, 2.32 h/d for cows that were slightly lame, and 4.31 h/d for cows that were moderately lame in MAT herds compared with equivalent cows in SAND herds. In MAT herds, the increase in time spent standing in the stall in moderately lame cows was associated with a significant reduction in stall use sessions per day, which impacted daily lying time. Although cause and effect are not clear, these findings have implications for housing, comfort, and care of cows in dairy herds with different types of free stall surfaces.

Discussion on the management system technology implementation of multimedia classrooms in the digital campus

Science.gov (United States)

Wang, Bo

2018-04-01

Based on the digitized information and network, digital campus is an integration of teaching, management, science and research, life service and technology service, and it is one of the current mainstream construction form of campus function. This paper regarded the "mobile computing" core digital environment construction development as the background, explored the multiple management system technology content design and achievement of multimedia classrooms in digital campus and scientifically proved the technology superiority of management system.

Coping Styles with Student Misbehavior as Mediators of Teachers' Classroom Management Strategies

Science.gov (United States)

Tran, Van Dat

2016-01-01

The purpose of the present study is to identify how teachers' use of various coping styles with student misbehavior, and the extent to which these relate to their classroom management techniques -- punishment, recognition and reward, hinting, discussion, and aggression. It examines data from 397 junior high school teachers in Vietnam. The results…

Examining Preservice Teachers' Classroom Management Decisions in Three Case-Based Teaching Approaches

Science.gov (United States)

Cevik, Yasemin Demiraslan; Andre, Thomas

2013-01-01

This study was aimed at comparing the impact of three types of case-based approaches (worked example, faded work example, and case-based reasoning) on preservice teachers' decision making and reasoning skills related to realistic classroom management situations. Participants in this study received a short-term implementation of one of these three…

Principles of Classroom Management: A Professional Decision-Making Model, 7th Edition

Science.gov (United States)

Levin, James; Nolan, James F.

2014-01-01

This text takes a decision-making model approach to classroom management. It provides teachers with a very practical system to influence students to choose to behave productively and to strive for academic success. This widely used text presents an array of decision-making options that guide teachers in developing positive, pro-social classroom…

Prediction of rotating stall within an impeller of a centrifugal pump based on spectral analysis of pressure and velocity data

International Nuclear Information System (INIS)

Ullum, Ulrik; Wright, Jennifer; Dayi, Oguz; Ecder, Ali; Soulaimani, Azzeddine; Piche, Robert; Kamath, Hemant

2006-01-01

Experimental data, which was acquired in two centrifugal pumps and provided by Grundfos A/S, were analysed to determine if rotating stall could be detected from the velocity and pressure time series. The pressure data, which were uniformly acquired in time at high sample rates(10 kHz), were measured simultaneously in four adjacent di.user channels just downstream of the impeller outlet. The velocity data, which were non-uniformly sampled in time at fairly low rates(100 Hz to 3.5 kHz), were acquired either in or downstream of the impeller. Two di.erent methodologies were employed for detection of stall. The first method, which involved direct analysis of raw data, yielded qualitatively useful flow reversal information from the time series for the radial velocity. The second approach, which was based on power spectrum analysis of velocity and pressure data, could detect the onset and identify the frequency of rotating stall to a satisfactory extent in one of the two pumps. Nearly identical stall frequencies were observed in both velocity and pressure power spectra and this rotating stall phenomenon, which occurred at a very low frequency relative to the impeller speed, did not reveal any noticeable degree of sensitivity to the flow rate. In the other pump, where the available data was limited to velocity time series, the power spectrum analysis was successful in detecting stationary stall for a 6 bladed impeller but did not provide conclusive results for the existence of stall in the case of the 7 bladed impeller. Recommendations on the type of experimental data required for accurate detection of stall are provided based upon the present study

Airborne Microorganisms in Tie-stall Dairy Barns from Brasov County

Directory of Open Access Journals (Sweden)

Silvana Popescu

2011-05-01

Full Text Available The aim of this study was the assessment of the airborne microorganisms in tie-stall dairy cattle barns, through determination of the total number of bacteria (mesophilic bacteria, staphylococci, streptococci and gram-negative bacteria and fungi. We investigated 8 dairy cattle barns with tie-stalls in Brasov County during the winter of 2009. The mean numbers of bacteria and fungi in the morning and in the evening were: 1.02 °— 105 - 1.26 °— 105 CFU/m3 for mesophilic bacteria, 5.34 °— 104 - 5.91 °— 104 CFU/m3 for staphylococci, 2.93 °— 104 - 3.60 °— 104 CFU/m3 for streptococci, 2.17 °— 103 - 3.48 °— 103 CFU/m3 for gram-negative bacteria and 1.54 °— 104 - 2.75 °— 104 CFU/m3 for fungi. In the investigated cattle houses staphylococci represented 52.35 – 46.90%, streptococci were 28.73 – 28.57%, and the gram-negative bacteria were 2.13 – 2.76% within the overall number of mesophilic bacteria. The numbers of bacteria and fungi were slightly elevated in the evening comparative to the morning, but the differences were statistically insignificant (p>0.05. The great numbers of bacteria and fungi in the air of dairy cattle tie-stall barns indicate an elevated risk of disease for animals and human workers.

A dynamic stall model for airfoils with deformable trailing edges

DEFF Research Database (Denmark)

Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Christian

2009-01-01

, lead-lag, pitch, trailing-edge flapping. In the linear region, the model reduces to the inviscid model, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa......The present work contains an extension of the Beddoes-Leishman-type dynamic stall model. In this work, a deformable trailing-edge flap has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave...... for the attached flow region and Hansen et al. The model is compared qualitatively to wind tunnel measurements of a Riso/ B1-18 blade section equipped with deformable trailing-edge flap devices in the form of piezoelectric devices. Copyright © 2009 John Wiley & Sons, Ltd....

Simulating Dynamic Stall Effects for Vertical Axis Wind Turbines Applying a Double Multiple Streamtube Model

Directory of Open Access Journals (Sweden)

Eduard Dyachuk

2015-02-01

Full Text Available The complex unsteady aerodynamics of vertical axis wind turbines (VAWT poses significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions for VAWTs, and it is in the focus of the study. Two dynamic stall models are compared: the widely-used Gormont model and a Leishman–Beddoes-type model. The models are included in a double multiple streamtube model. The effects of flow curvature and flow expansion are also considered. The model results are assessed against the measured data on a Darrieus turbine with curved blades. To study the dynamic stall effects, the comparison of force coefficients between the simulations and experiments is done at low tip speed ratios. Simulations show that the Leishman–Beddoes model outperforms the Gormont model for all tested conditions.

Compressible dynamic stall vorticity flux control using a dynamic ...

Indian Academy of Sciences (India)

systems, such as a wind turbine, are prevented from ever entering dynamic stall, essentially disregarding potential ... future generations of such systems, an overwhelming need has developed to avail this benefit safely. ... approach must diffuse the vorticity prior to its coalescence, but keep the vorticity over the airfoil up to ...

DNA replication: stalling a fork for imprinting and switching

DEFF Research Database (Denmark)

Egel, Richard

2004-01-01

Mating-type switching in fission yeast has long been known to be directed by a DNA 'imprint'. This imprint has now been firmly characterized as a protected site-specific and strand-specific nick. New work also links the widely conserved Swi1-Swi3 complex to the protection of stalled replication...

Band-pass filtering algorithms for adaptive control of compressor pre-stall modes in aircraft gas-turbine engine

Science.gov (United States)

Kuznetsova, T. A.

2018-05-01

The methods for increasing gas-turbine aircraft engines' (GTE) adaptive properties to interference based on empowerment of automatic control systems (ACS) are analyzed. The flow pulsation in suction and a discharge line of the compressor, which may cause the stall, are considered as the interference. The algorithmic solution to the problem of GTE pre-stall modes’ control adapted to stability boundary is proposed. The aim of the study is to develop the band-pass filtering algorithms to provide the detection functions of the compressor pre-stall modes for ACS GTE. The characteristic feature of pre-stall effect is the increase of pressure pulsation amplitude over the impeller at the multiples of the rotor’ frequencies. The used method is based on a band-pass filter combining low-pass and high-pass digital filters. The impulse response of the high-pass filter is determined through a known low-pass filter impulse response by spectral inversion. The resulting transfer function of the second order band-pass filter (BPF) corresponds to a stable system. The two circuit implementations of BPF are synthesized. Designed band-pass filtering algorithms were tested in MATLAB environment. Comparative analysis of amplitude-frequency response of proposed implementation allows choosing the BPF scheme providing the best quality of filtration. The BPF reaction to the periodic sinusoidal signal, simulating the experimentally obtained pressure pulsation function in the pre-stall mode, was considered. The results of model experiment demonstrated the effectiveness of applying band-pass filtering algorithms as part of ACS to identify the pre-stall mode of the compressor for detection of pressure fluctuations’ peaks, characterizing the compressor’s approach to the stability boundary.

Classroom management: Teachers’ skills and differentiation according to posts held at school – A research study with primary school teachers

OpenAIRE

Valente, Sónia; Veiga, Feliciano

2016-01-01

Conceptual framework: The concept of classroom management emerges as a relevant and contemporary study area, since due to a shortage of empirical studies, there is a clear need for deeper explanatory theoretical models. Teachers use strategies for classroom management but still encounter barriers when defining conditions which may enhance the teaching and learning process. Objective: the present research intended to answer the following research questions: «How are teachers ...

The Relation of Work Environment and Stress in Classroom Management among Preschool Teachers

Directory of Open Access Journals (Sweden)

Abdul Said Ambotang

2011-10-01

Full Text Available The purpose of this research is to observe how far preschool teachers endure stress in carrying out their job which is influenced by the work climate including the management of classroom. This research is carried out by choosing a group of 55 preschool teachers as respondents in the district of Keningau Sabah. Data is analyzed using descriptive method (mean, inferential (T-test Statistic, one way ANOVA and Pearson correlation. Result showed that there were high positive relationships between the work climate with stress level among the teachers. (r = 0.807, p<0.01 and classroom management with level of stress (r = 0.770, p< 0.01. It is hoped that with the information obtained by this research will assist the Malaysian Ministry of Education in planning and designing a suitable programme to overcome the stress problem faced by teachers especially preschool teachers towards improving the teaching profession quality in the near future.

Success and Near Misses: Pre-Service Teachers' Use, Confidence and Success in Various Classroom Management Strategies

Science.gov (United States)

Reupert, Andrea; Woodcock, Stuart

2010-01-01

While the importance of effective classroom management is repeatedly made, there is little comprehensive research identifying the management strategies pre-service teachers employ, nor how successful or confident they find various strategies. Accordingly, 336 Canadian pre-service teachers were surveyed. It was found that pre-service teachers…

The effectiveness of computer-managed instruction versus traditional classroom lecture on achievement outcomes.

Science.gov (United States)

Schmidt, S M; Arndt, M J; Gaston, S; Miller, B J

1991-01-01

This controlled experimental study examines the effect of two teaching methods on achievement outcomes from a 15-week, 2 credit hour semester course taught at two midwestern universities. Students were randomly assigned to either computer-managed instruction in which faculty function as tutors or the traditional classroom course of study. In addition, the effects of age, grade point average, attitudes toward computers, and satisfaction with the course on teaching method were analyzed using analysis of covariance. Younger students achieved better scores than did older students. Regardless of teaching method, however, neither method appeared to be better than the other for teaching course content. Students did not prefer one method over the other as indicated by their satisfaction scores. With demands upon university faculty to conduct research and publish, alternative methods of teaching that free faculty from the classroom should be considered. This study suggests that educators can select such an alternative teaching method to traditional classroom teaching without sacrificing quality education for certain courses.

Accounting for biases in riboprofiling data indicates a major role for proline in stalling translation.

Science.gov (United States)

Artieri, Carlo G; Fraser, Hunter B

2014-12-01

The recent advent of ribosome profiling-sequencing of short ribosome-bound fragments of mRNA-has offered an unprecedented opportunity to interrogate the sequence features responsible for modulating translational rates. Nevertheless, numerous analyses of the first riboprofiling data set have produced equivocal and often incompatible results. Here we analyze three independent yeast riboprofiling data sets, including two with much higher coverage than previously available, and find that all three show substantial technical sequence biases that confound interpretations of ribosomal occupancy. After accounting for these biases, we find no effect of previously implicated factors on ribosomal pausing. Rather, we find that incorporation of proline, whose unique side-chain stalls peptide synthesis in vitro, also slows the ribosome in vivo. We also reanalyze a method that implicated positively charged amino acids as the major determinant of ribosomal stalling and demonstrate that it produces false signals of stalling in low-coverage data. Our results suggest that any analysis of riboprofiling data should account for sequencing biases and sparse coverage. To this end, we establish a robust methodology that enables analysis of ribosome profiling data without prior assumptions regarding which positions spanned by the ribosome cause stalling. © 2014 Artieri and Fraser; Published by Cold Spring Harbor Laboratory Press.

Application of classroom simulators in the training of managers at CANDU plants

Energy Technology Data Exchange (ETDEWEB)

Bereznai, G.; Rizk, K., E-mail: george.bereznai@uoit.ca, E-mail: khalid.rizk@uoit.ca [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada)

2015-07-01

Technical managers of Canada's nuclear power plants are required to have in-depth knowledge of the normal and abnormal integrated unit operations typical of the plant at which they work. The Advanced Operations Overview for Managers (AOOM) training program was developed by Ontario Power Generation to fulfil this need for many of its managers. The program makes extensive use of 'classroom' simulators that have the same software models as the full-scope training simulators, but use graphical user interface to replicate the control room devices. For the last several years the AOOM program has been delivered by the University of Ontario Institute of Technology. (author)

Application of classroom simulators in the training of managers at CANDU plants

International Nuclear Information System (INIS)

Bereznai, G.; Rizk, K.

2015-01-01

Technical managers of Canada's nuclear power plants are required to have in-depth knowledge of the normal and abnormal integrated unit operations typical of the plant at which they work. The Advanced Operations Overview for Managers (AOOM) training program was developed by Ontario Power Generation to fulfil this need for many of its managers. The program makes extensive use of 'classroom' simulators that have the same software models as the full-scope training simulators, but use graphical user interface to replicate the control room devices. For the last several years the AOOM program has been delivered by the University of Ontario Institute of Technology. (author)

The influence of elevated feed stalls on feeding behaviour of lactating dairy cows

Directory of Open Access Journals (Sweden)

Barbara Benz

2014-10-01

Full Text Available The performance level of high yielding cows can only be guaranteed by high quality forage and high feed intake. An about 15–20 cm elevated and 160 cm long feed stall with rubber flooring doesn’t only offer undisturbed meals but also a yielding and dry standing surface. In a pilot stable with 130 dairy cows (German Simmental the feeding alley was subsequently equipped with elevated feed stalls. The results show that animals frequented the feeding barn less often while the duration of single meals prolonged. The specific behavioural changes differed depending on milk yield and number of lactation.

A Small-Scale Study on Student Teachers' Perceptions of Classroom Management and Methods for Dealing with Misbehaviour

Science.gov (United States)

Atici, Meral

2007-01-01

The purpose of this study is to identify student teachers' perceptions of classroom management and methods for dealing with misbehaviour. In-depth interviews with nine student teachers at Cukurova University (CU) in Turkey have been conducted twice, prior to and at the end of their teaching practice. Instructional management, behaviour management,…

Scholar Dollars: Their Use in Classroom Management.

Science.gov (United States)

Deery, Ruth

Suggestions and background information to help teachers use classroom currency to influence students' behavior and academic efforts are provided. There are five parts to the publication. Part 1 discusses the many uses of classroom currency in teaching economics content, for motivation, and in discipline. For example, if teachers find that…

A kinesthetic-tactual display for stall deterrence

Science.gov (United States)

Gilson, R. D.; Ventola, R. W.; Fenton, R. E.

1975-01-01

A kinesthetic tactual display may be effectively used as a control aid per previous flight tests. Angle of attack information would be continuously presented to a pilot, via this display, during critical operational phases where stalls are probable. A two phase plan for evaluating this concept is presented. A first development phase would encompass: (1) display fabrication for a conventional control yoke; (2) its installation, together with other necessary instrumentation, in an experimental aircraft; and (3) preliminary flight testing by experienced pilots.

Design of advanced airfoil for stall-regulated wind turbines

Directory of Open Access Journals (Sweden)

F. Grasso

2017-07-01

Full Text Available Nowadays, all the modern megawatt-class wind turbines make use of pitch control to optimise the rotor performance and control the turbine. However, for kilowatt-range machines, stall-regulated solutions are still attractive and largely used for their simplicity and robustness. In the design phase, the aerodynamics plays a crucial role, especially concerning the selection/design of the necessary airfoils. This is because the airfoil performance is supposed to guarantee high wind turbine performance but also the necessary machine control capabilities. In the present work, the design of a new airfoil dedicated to stall machines is discussed. The design strategy makes use of a numerical optimisation scheme, where a gradient-based algorithm is coupled with the RFOIL code and an original Bezier-curves-based parameterisation to describe the airfoil shape. The performances of the new airfoil are compared in free- and fixed-transition conditions. In addition, the performance of the rotor is analysed, comparing the impact of the new geometry with alternative candidates. The results show that the new airfoil offers better performance and control than existing candidates do.

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

International Nuclear Information System (INIS)

Pacot, Olivier; Avellan, François; Kato, Chisachi

2014-01-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

Science.gov (United States)

Pacot, Olivier; Kato, Chisachi; Avellan, François

2014-03-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment.

Modelling of multiple short-length-scale stall cells in an axial compressor using evolved GMDH neural networks

International Nuclear Information System (INIS)

Amanifard, N.; Nariman-Zadeh, N.; Farahani, M.H.; Khalkhali, A.

2008-01-01

Over the past 15 years there have been several research efforts to capture the stall inception nature in axial flow compressors. However previous analytical models could not explain the formation of short-length-scale stall cells. This paper provides a new model based on evolved GMDH neural network for transient evolution of multiple short-length-scale stall cells in an axial compressor. Genetic Algorithms (GAs) are also employed for optimal design of connectivity configuration of such GMDH-type neural networks. In this way, low-pass filter (LPF) pressure trace near the rotor leading edge is modelled with respect to the variation of pressure coefficient, flow rate coefficient, and number of rotor rotations which are defined as inputs

Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence

Science.gov (United States)

Feroskhan, Mir Alikhan Bin Mohammad

Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and

A model for the selective amplification of spatially coherent waves in a centrifugal compressor on the verge of rotating stall

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1993-01-01

A simple model for the stability zones of a low speed centrifugal compressor is developed, with the goal of understanding the driving mechanism for the changes in stalling behavior predicted for, and observed in, the Purdue Low Speed Centrifugal Research Compressor Facility. To this end, earlier analyses of rotating stall suppression in centrifugal compressors are presented in a reduced form that preserves the essential parameters of the model that affect the stalling behavior of the compressor. The model is then used to illuminate the relationship between compressor geometry, expected mode shape, and regions of amplification for weak waves which are indicative of the susceptibility of the system to rotating stall. The results demonstrate that increasing the stagger angle of the diffuser vanes, and consequently the diffusion path length, results in the compressor moving towards a condition where higher-order spatial modes are excited during stall initiation. Similarly, flow acceleration in the diffuser section caused by an increase in the number of diffuser vanes also results in the excitation of higher modes.

Code Switching in the Classroom: A Case Study of Economics and Management Students at the University of Sfax, Tunisia

Science.gov (United States)

Bach Baoueb, Sallouha Lamia; Toumi, Naouel

2012-01-01

This case study explores the motivations for code switching (CS) in the interactions of Tunisian students at the faculty of Economics and Management in Sfax, Tunisia. The study focuses on students' (EMSs) classroom conversations and out-of-classroom peer interactions. The analysis of the social motivations of EMSs' CS behaviour shows that…

Investigating teacher and student effects of the Incredible Years Classroom Management Program in early elementary school.

Science.gov (United States)

Murray, Desiree W; Rabiner, David L; Kuhn, Laura; Pan, Yi; Sabet, Raha Forooz

2018-04-01

The present paper reports on the results of a cluster randomized trial of the Incredible Years® Teacher Classroom Management Program (IY-TCM) and its effects on early elementary teachers' management strategies, classroom climate, and students' emotion regulation, attention, and academic competence. IY-TCM was implemented in 11 rural and semi-rural schools with K-2 teachers and a diverse student sample. Outcomes were compared for 45 teachers who participated in five full day training workshops and brief classroom consultation and 46 control teachers; these 91 teachers had a total of 1192 students. A high level of teacher satisfaction was found and specific aspects of the training considered most valuable for early elementary teachers were identified. Hierarchical linear modeling indicated a statistically significant intervention effect on Positive Climate in the classroom (d=0.45) that did not sustain into the next school year. No main effects on student outcomes were observed, although a priori moderator analyses indicated that students with elevated social-behavioral difficulties benefitted with regard to prosocial behavior (d=0.54) and inattention (d=-0.34). Results highlight potential benefits and limitations of a universal teacher training program for elementary students, and suggest strategies for future delivery of the IY-TCM program and areas for future research. Copyright © 2017 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Curriculum Connection: Create a Classroom Community.

Science.gov (United States)

Donlan, Leni

1991-01-01

One elementary teacher runs her classroom as a technology-based token economy. Students hold classroom jobs and use software to track money earned, manage checking accounts, and disburse classroom cash. The strategy boosts math and technology skills. A list of software programs is included. (SM)

Classroom

Indian Academy of Sciences (India)

in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. ... research, could then both inject greater vigour into teaching of ... ture, forestry and fishery sciences, management of natural resources.

Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio.

Science.gov (United States)

Kruyt, Jan W; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

2015-04-06

Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Unsteady behavior of leading-edge vortex and diffuser stall in a centrifugal compressor with vaned diffuser

Science.gov (United States)

Fujisawa, Nobumichi; Hara, Shotaro; Ohta, Yutaka

2016-02-01

The characteristics of a rotating stall of an impeller and diffuser and the evolution of a vortex generated at the diffuser leading-edge (i.e., the leading-edge vortex (LEV)) in a centrifugal compressor were investigated by experiments and numerical analysis. The results of the experiments revealed that both the impeller and diffuser rotating stalls occurred at 55 and 25 Hz during off-design flow operation. For both, stall cells existed only on the shroud side of the flow passages, which is very close to the source location of the LEV. According to the CFD results, the LEV is made up of multiple vortices. The LEV is a combination of a separated vortex near the leading- edge and a longitudinal vortex generated by the extended tip-leakage flow from the impeller. Therefore, the LEV is generated by the accumulation of vorticity caused by the velocity gradient of the impeller discharge flow. In partial-flow operation, the spanwise extent and the position of the LEV origin are temporarily transmuted. The LEV develops with a drop in the velocity in the diffuser passage and forms a significant blockage within the diffuser passage. Therefore, the LEV may be regarded as being one of the causes of a diffuser stall in a centrifugal compressor.

Torey Hayden's Teacher Lore: Classroom Behavior Management of Children with Emotional and Behavioral Disorders

Science.gov (United States)

Marlowe, Mike; Disney, Gayle

2006-01-01

Torey Hayden's portrayal of classroom behavior management in her teacher lore, autobiographical writings about teaching children with emotional and behavioral disorders, is examined. Five of her books were sampled: "One child", "Somebody else's kids", "Just another kid", "Ghost girl" and "Beautiful child". Each of these books unfolds within the…

A flight investigation of the ultra-deep-stall descent and spin recovery characteristics of a 1/6 scale radiocontrolled model of the Piper PA38 Tomahawk

Science.gov (United States)

Blanchard, W. S., Jr.

1981-01-01

Ultradeep stall descent and spin recovery characteristics of a 1/6 scale radio controlled model of the Piper PA38 Tomahawk aircraft was investigated. It was shown that the full scale PA38 is a suitable aircraft for conducting ultradeep stall research. Spin recovery was accomplished satisfactorily by entry to the ultradeep stall mode, followed by the exit from the ultradeep stall mode. It is concluded that since the PA38 has excellent spin recovery characteristics using normal recovery techniques (opposite rudder and forward control colum pressure), recovery using ultradeep stall would be beneficial only if the pilot suffered from disorientation.

Robust post-stall perching with a simple fixed-wing glider using LQR-Trees

International Nuclear Information System (INIS)

Moore, Joseph; Cory, Rick; Tedrake, Russ

2014-01-01

Birds routinely execute post-stall maneuvers with a speed and precision far beyond the capabilities of our best aircraft control systems. One remarkable example is a bird exploiting post-stall pressure drag in order to rapidly decelerate to land on a perch. Stall is typically associated with a loss of control authority, and it is tempting to attribute this agility of birds to the intricate morphology of the wings and tail, to their precision sensing apparatus, or their ability to perform thrust vectoring. Here we ask whether an extremely simple fixed-wing glider (no propeller) with only a single actuator in the tail is capable of landing precisely on a perch from a large range of initial conditions. To answer this question, we focus on the design of the flight control system; building upon previous work which used linear feedback control design based on quadratic regulators (LQR), we develop nonlinear feedback control based on nonlinear model-predictive control and ‘LQR-Trees’. Through simulation using a flat-plate model of the glider, we find that both nonlinear methods are capable of achieving an accurate bird-like perching maneuver from a large range of initial conditions; the ‘LQR-Trees’ algorithm is particularly useful due to its low computational burden at runtime and its inherent performance guarantees. With this in mind, we then implement the ‘LQR-Trees’ algorithm on real hardware and demonstrate a 95 percent perching success rate over 147 flights for a wide range of initial speeds. These results suggest that, at least in the absence of significant disturbances like wind gusts, complex wing morphology and sensing are not strictly required to achieve accurate and robust perching even in the post-stall flow regime. (papers)

EFFECT OF GROUPING ON CLASSROOM COMMUNITIES

OpenAIRE

Toriumi, Fujio; Ishii, Kenichiro

2006-01-01

In the education field, the management of student relation-ships is one of the most important duties of teachers. Such management usually reflects the teacher's abilities and experiences. The purpose of this study is to clarify management methods to realize appropriate classroom community structures. In this study, we simulated a community-forming mechanism to clarify the influence of grouping on classroom community formation. We presented a community through a communication network using Hei...

A Mosquito in the Classroom: Using the Cooperative Business Model to Foster Paradoxical Thinking in Management Education

Science.gov (United States)

Audebrand, Luc K.; Camus, Annie; Michaud, Valérie

2017-01-01

Although the paradox perspective is gaining increasing attention among management scholars, most of us continue to struggle with addressing this challenging topic in the classroom, as it seems out of reach for many students. In this article, we describe a potentially beneficial way to approach paradoxical thinking in management education: teaching…

Identification of phlebovirus and arenavirus RNA sequences that stall and repress the exoribonuclease XRN1.

Science.gov (United States)

Charley, Phillida A; Wilusz, Carol J; Wilusz, Jeffrey

2018-01-05

Regulated mRNA decay plays a vital role in determining both the level and quality of cellular gene expression. Viral RNAs must successfully evade this host RNA decay machinery to establish a productive infection. One way for RNA viruses to accomplish this is to target the cellular exoribonuclease XRN1, because this enzyme is accessible in the cytoplasm and plays a major role in mRNA decay. Members of the Flaviviridae use RNA structures in their 5'- or 3'-untranslated regions to stall and repress XRN1, effectively stabilizing viral RNAs while also causing significant dysregulation of host cell mRNA stability. Here, we use a series of biochemical assays to demonstrate that the 3'-terminal portion of the nucleocapsid (N) mRNA of Rift Valley fever virus, a phlebovirus of the Bunyaviridae family, also can effectively stall and repress XRN1. The region responsible for impeding XRN1 includes a G-rich portion that likely forms a G-quadruplex structure. The 3'-terminal portions of ambisense-derived transcripts of multiple arenaviruses also stalled XRN1. Therefore, we conclude that RNAs from two additional families of mammalian RNA viruses stall and repress XRN1. This observation. emphasizes the importance and commonality of this viral strategy to interfere with the 5'-to-3'-exoribonuclease component of the cytoplasmic RNA decay machinery. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Positive Classroom Management. A Step-by-Step Guide to Successfully Running the Show Without Destroying Student Dignity. 2nd Edition.

Science.gov (United States)

DiGiulio, Robert

This book provides K-12 teachers with concrete, step-by-step guidance on how to improve student behavior through positive classroom management. It explains how to take control of the classroom, offering an alternative to threats, rewards, and punishments. The book is divided into an introduction and three sections with seven chapters. The…

Effect of Leadership Experience on Agricultural Education Student Teacher Self-Efficacy in Classroom Management

Science.gov (United States)

Wolf, Kattlyn J.; Foster, Daniel D.; Birkenholz, Robert J.

2009-01-01

Beginning agriculture teachers often cite classroom management as the most important problem they face in their careers. The purpose of this study was to assess the effect of leadership experience on self-perceived teacher efficacy among agricultural education student teachers. The three dimensions of teacher efficacy addressed in this study…

Social and Emotional Pedagogies: Critiquing the New Orthodoxy of Emotion in Classroom Behaviour Management

Science.gov (United States)

Gillies, Val

2011-01-01

This paper examines new structured attempts to address and manage emotions in the classroom. Critical analysis focuses on the broad emotional literacy agenda operating within schools, and more specifically the Social and Emotional Aspects of Learning (SEAL) programme. Data are drawn on from an ethnographic study located in Behaviour Support Units…

Dynamic Stall Control on the Wind Turbine Airfoil via a Co-Flow Jet

Directory of Open Access Journals (Sweden)

He-Yong Xu

2016-06-01

Full Text Available Dynamic stall control of a S809 airfoil is numerically investigated by implementing a co-flow jet (CFJ. The numerical methods of the solver are validated by comparing results with the baseline experiment as well as a NACA 6415-based CFJ experiment, showing good agreement in both static and dynamic characteristics. The CFJ airfoil with inactive jet is simulated to study the impact that the jet channel imposes upon the dynamic characteristics. It is shown that the presence of a long jet channel could cause a negative effect of decreasing lift and increasing drag, leading to fluctuating extreme loads in terms of drag and moment. The main focus of the present research is the investigation of the dynamic characteristics of the CFJ airfoil with three different jet momentum coefficients, which are compared with the baseline, giving encouraging results. Dynamic stall can be greatly suppressed, showing a very good control performance of significantly increased lift and reduced drag and moment. Analysis of the amplitude of variation in the aerodynamic coefficients indicates that the fluctuating extreme aerodynamic loads are significantly alleviated, which is conducive to structural reliability and improved life cycle. The energy consumption analysis shows that the CFJ concept is applicable and economical in controlling dynamic stall.

Breaking Bad Behaviours: A New Tool for Learning Classroom Management using Virtual Reality

Directory of Open Access Journals (Sweden)

Jean-Luc Lugrin

2016-11-01

Full Text Available This article presents an immersive Virtual Reality (VR system for training classroommanagement skills, with a specific focus on learning to manage disruptive student behaviourin face-to-face, one-to-many teaching scenarios. The core of the system is a real-time 3Dvirtual simulation of a classroom, populated by twenty-four semi-autonomous virtual students.The system has been designed as a companion tool for classroom management seminars ina syllabus for primary and secondary school teachers. Whereby, it will allow lecturers to linktheory with practice, using the medium of VR. The system is therefore designed for two users: atrainee teacher and an instructor supervising the training session. The teacher is immersed in areal-time 3D simulation of a classroom by means of a head-mounted display and headphone.The instructor operates a graphical desktop console which renders a view of the class and theteacher, whose avatar movements are captured by a marker-less tracking system. This consoleincludes a 2D graphics menu with convenient behaviour and feedback control mechanisms toprovide human-guided training sessions. The system is built using low-cost consumer hardwareand software. Its architecture and technical design are described in detail. A first evaluationconfirms its conformance to critical usability requirements (i.e., safety and comfort, believability,simplicity, acceptability, extensibility, affordability and mobility. Our initial results are promising,and constitute the necessary first step toward a possible investigation of the efficiency andeffectiveness of such a system in terms of learning outcomes and experience.

Nonlinear Aeroelastic Study of Stall Induced Oscillation in a Symmetric Airfoil

NARCIS (Netherlands)

Sarkar, S.; Bijl, H.

2006-01-01

In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Increased flexibility of modern turbine blades makes them more susceptible to aeroelastic instabilities. Complex oscillation modes like flap/lead-lag are of particular concern, which give way

Checkpoint responses to replication stalling: inducing tolerance and preventing mutagenesis

Energy Technology Data Exchange (ETDEWEB)

Kai, Mihoko; Wang, Teresa S.-F

2003-11-27

Replication mutants often exhibit a mutator phenotype characterized by point mutations, single base frameshifts, and the deletion or duplication of sequences flanked by homologous repeats. Mutation in genes encoding checkpoint proteins can significantly affect the mutator phenotype. Here, we use fission yeast (Schizosaccharomyces pombe) as a model system to discuss the checkpoint responses to replication perturbations induced by replication mutants. Checkpoint activation induced by a DNA polymerase mutant, aside from delay of mitotic entry, up-regulates the translesion polymerase DinB (Pol{kappa}). Checkpoint Rad9-Rad1-Hus1 (9-1-1) complex, which is loaded onto chromatin by the Rad17-Rfc2-5 checkpoint complex in response to replication perturbation, recruits DinB onto chromatin to generate the point mutations and single nucleotide frameshifts in the replication mutator. This chain of events reveals a novel checkpoint-induced tolerance mechanism that allows cells to cope with replication perturbation, presumably to make possible restarting stalled replication forks. Fission yeast Cds1 kinase plays an essential role in maintaining DNA replication fork stability in the face of DNA damage and replication fork stalling. Cds1 kinase is known to regulate three proteins that are implicated in maintaining replication fork stability: Mus81-Eme1, a hetero-dimeric structure-specific endonuclease complex; Rqh1, a RecQ-family helicase involved in suppressing inappropriate recombination during replication; and Rad60, a protein required for recombinational repair during replication. These Cds1-regulated proteins are thought to cooperatively prevent mutagenesis and maintain replication fork stability in cells under replication stress. These checkpoint-regulated processes allow cells to survive replication perturbation by preventing stalled replication forks from degenerating into deleterious DNA structures resulting in genomic instability and cancer development.

Checkpoint responses to replication stalling: inducing tolerance and preventing mutagenesis

International Nuclear Information System (INIS)

Kai, Mihoko; Wang, Teresa S.-F.

2003-01-01

Replication mutants often exhibit a mutator phenotype characterized by point mutations, single base frameshifts, and the deletion or duplication of sequences flanked by homologous repeats. Mutation in genes encoding checkpoint proteins can significantly affect the mutator phenotype. Here, we use fission yeast (Schizosaccharomyces pombe) as a model system to discuss the checkpoint responses to replication perturbations induced by replication mutants. Checkpoint activation induced by a DNA polymerase mutant, aside from delay of mitotic entry, up-regulates the translesion polymerase DinB (Polκ). Checkpoint Rad9-Rad1-Hus1 (9-1-1) complex, which is loaded onto chromatin by the Rad17-Rfc2-5 checkpoint complex in response to replication perturbation, recruits DinB onto chromatin to generate the point mutations and single nucleotide frameshifts in the replication mutator. This chain of events reveals a novel checkpoint-induced tolerance mechanism that allows cells to cope with replication perturbation, presumably to make possible restarting stalled replication forks. Fission yeast Cds1 kinase plays an essential role in maintaining DNA replication fork stability in the face of DNA damage and replication fork stalling. Cds1 kinase is known to regulate three proteins that are implicated in maintaining replication fork stability: Mus81-Eme1, a hetero-dimeric structure-specific endonuclease complex; Rqh1, a RecQ-family helicase involved in suppressing inappropriate recombination during replication; and Rad60, a protein required for recombinational repair during replication. These Cds1-regulated proteins are thought to cooperatively prevent mutagenesis and maintain replication fork stability in cells under replication stress. These checkpoint-regulated processes allow cells to survive replication perturbation by preventing stalled replication forks from degenerating into deleterious DNA structures resulting in genomic instability and cancer development

Ordering within Moral Orders to Manage Classroom Trouble

Science.gov (United States)

Doherty, Catherine; McGregor, Rowena; Shield, Paul

2016-01-01

This paper demonstrates how classroom trouble warranting teacher intervention can stem from transgressions in different layers of the complex moral order regulating classroom interactions. The paper builds from Durkheim's treatment of schooling as the institution responsible for the inculcation of a shared moral order, Bernstein's distinction…

Pressure-based high-order TVD methodology for dynamic stall control

Science.gov (United States)

Yang, H. Q.; Przekwas, A. J.

1992-01-01

The quantitative prediction of the dynamics of separating unsteady flows, such as dynamic stall, is of crucial importance. This six-month SBIR Phase 1 study has developed several new pressure-based methodologies for solving 3D Navier-Stokes equations in both stationary and moving (body-comforting) coordinates. The present pressure-based algorithm is equally efficient for low speed incompressible flows and high speed compressible flows. The discretization of convective terms by the presently developed high-order TVD schemes requires no artificial dissipation and can properly resolve the concentrated vortices in the wing-body with minimum numerical diffusion. It is demonstrated that the proposed Newton's iteration technique not only increases the convergence rate but also strongly couples the iteration between pressure and velocities. The proposed hyperbolization of the pressure correction equation is shown to increase the solver's efficiency. The above proposed methodologies were implemented in an existing CFD code, REFLEQS. The modified code was used to simulate both static and dynamic stalls on two- and three-dimensional wing-body configurations. Three-dimensional effect and flow physics are discussed.

The Special Educator's Toolkit: Everything You Need to Organize, Manage, and Monitor Your Classroom

Science.gov (United States)

Golden, Cindy

2012-01-01

Overwhelmed special educators: Reduce your stress and support student success with this practical toolkit for whole-classroom organization. A lifesaver for special educators in any K-12 setting, this book-and-CD set will help teachers expertly manage everything, from schedules and paperwork to student supports and behavior plans. Cindy Golden, a…

Can You Skype Me Now? Developing Teachers' Classroom Management Practices through Virtual Coaching

Science.gov (United States)

Rock, Marcia L.; Schoenfeld, Naomi; Zigmond, Naomi; Gable, Robert A.; Gregg, Madeleine; Ploessl, Donna M.; Salter, Ashley

2013-01-01

In this article, situated within the context of a larger ongoing study on the efficacy of Web-based virtual coaching, these authors describe a virtual coaching model for maximizing pre- and in-service teachers' effective use of evidence-based classroom management practices. They also provide a brief summary of previous results obtained…

A Method to Predict Compressor Stall in the TF34-100 Turbofan Engine Utilizing Real-Time Performance Data

Science.gov (United States)

2015-06-01

A METHOD TO PREDICT COMPRESSOR STALL IN THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE...THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE DATA THESIS Presented to the Faculty Department of Systems Engineering and...036 A METHOD TO PREDICT COMPRESSOR STALL IN THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE DATA Shuxiang ‘Albert’ Li, BS

Flow Observations with Tufts and Lampblack of the Stalling of Four Typical Airfoil Sections in the NACA Variable-density Tunnel

Science.gov (United States)

Abbott, Ira H; Sherman, Albert

1938-01-01

A preliminary investigation of the stalling processes of four typical airfoil sections was made over the critical range of the Reynolds Number. Motion pictures were taken of the movements of small silk tufts on the airfoil surface as the angle of attack increased through a range of angles including the stall. The boundary-layer flow also at certain angles of attack was indicated by the patterns formed by a suspension of lampblack in oil brushed onto the airfoil surface. These observations were analyzed together with corresponding force-test measurements to derive a picture of the stalling processes of airfoils.

Indoor and outdoor concentrations of RSP, NO2 and selected volatile organic compounds at 32 shoe stalls located near busy roadways in Seoul, Korea

International Nuclear Information System (INIS)

Bae, Hyunjoo; Chung, Moonho; Yang, Wonho

2004-01-01

It is suspected that persons who work in indoor environments near busy roadways are exposed to elevated levels of air pollutants during working hours. This study evaluated the potential exposure and source contribution associated with traffic-related air pollution for workers (polishers and repairmen) in shoe stalls from each of 32 districts during working hours in Seoul, Korea. The shoe stalls have been located at very close distances to the busy roadways. In this study, shoe stall workers could be exposed to high levels of respirable suspended particulate (RSP), nitrogen dioxide (NO 2 ) and volatile organic compounds (VOCs) from outdoor sources such as traffic exhaust, as well as indoor sources in the shoe stalls such as dust on the shoes, portable gas ranges, organic solvents, adhesives and shoe polish. Compounds of particular note included indoor mean concentrations of benzene, toluene, m/p-xylene and o-xylene were 0.732, 6.777, 4.080 and 1.302 mg/m 3 , respectively, in all shoe stalls. Mean indoor/outdoor ratios for toluene and m/p-xylene concentrations were 54.52 and 20.84, respectively. The contribution of vehicle exhaust emissions to indoor air quality of shoe stalls was identified by means of correlating the relationships between simultaneously measured air pollutant concentrations indoors and outdoors. Unlike RSP and NO 2 , indoor VOCs concentrations of shoe stalls mainly originated from indoor sources vs. outdoor sources

Short revolving wings enable hovering animals to avoid stall and reduce drag

Science.gov (United States)

Lentink, David; Kruyt, Jan W.; Heijst, Gertjan F.; Altshuler, Douglas L.

2014-11-01

Long and slender wings reduce the drag of airplanes, helicopters, and gliding animals, which operate at low angle of attack (incidence). Remarkably, there is no evidence for such influence of wing aspect ratio on the energetics of hovering animals that operate their wings at much higher incidence. High incidence causes aircraft wings to stall, hovering animals avoid stall by generating an attached vortex along the leading edge of their wings that elevates lift. Hypotheses that explain this capability include the necessity for a short radial distance between the shoulder joint and wing tip, measured in chord lengths, instead of the long tip-to-tip distance that elevates aircraft performance. This stems from how hovering animals revolve their wings around a joint, a condition for which the precise effect of aspect ratio on stall performance is unknown. Here we show that the attachment of the leading edge vortex is determined by wing aspect ratio with respect to the center of rotation-for a suite of aspect ratios that represent both animal and aircraft wings. The vortex remains attached when the local radius is shorter than 4 chord lengths, and separates outboard on more slender wings. Like most other hovering animals, hummingbirds have wing aspect ratios between 3 and 4, much stubbier than helicopters. Our results show this makes their wings robust against flow separation, which reduces drag below values obtained with more slender wings. This revises our understanding of how aspect ratio improves performance at low Reynolds numbers.

Using Simulation to Support Novice Teachers' Classroom Management Skills: Comparing Traditional and Alternative Certification Groups

Science.gov (United States)

Pankowski, Jennifer; Walker, Joan T.

2016-01-01

Drawing from research on situated cognition and the development of expertise and simulations in professional education, we designed two simulation tasks that provided novice teachers with repeated opportunities to deliberately practice managing a classroom under no-fault conditions. The simulations immersed novices in two perennial classroom…

Complementary Roles of Care and Behavioral Control in Classroom Management: The Self-Determination Theory Perspective

Science.gov (United States)

Nie, Youyan; Lau, Shun

2009-01-01

This study examined how classroom management practices--care and behavioral control--were differentially associated with students' engagement, misbehavior, and satisfaction with school, using a large representative sample of 3196 Grade 9 students from 117 classes in Singapore. Results of hierarchical linear modeling showed differential relations.…

Animal hygiene assessment of microclimate in semi open free-stall barns for dairy cows

Directory of Open Access Journals (Sweden)

D. Dimov

2017-03-01

Full Text Available Abstract. The study was conducted in three semi open free-stall barns (B1, B2, and B3 for dairy cows with capacities for 120, 120 and 500 cows, respectively, from three different dairy farms (F-1, F-2 and F-3, situated in Central Southern Bulgaria. The investigated farms had the same production system – loose housing in semi open free-stall dairy barn. For each of the farms the main microclimatic parameters – air temperature, relative humidity and speed of airflow were recorded twice a month at 10.00 h 12.00 h, 14.00 h, 16.00 h and 18.00 h of the day inside the barns in three main technological zones - above the stalls, above manure and feed alleys and outside the buildings. It was found that: a Microclimatic parameters (air temperature, air relative humidity and speed of airflow in technological zones (above the stalls, the manure and feed alleys of three semi open free-stall dairy barns meet the animal hygienic requirements for all seasons according to Regulation No. 44 (2006. Exceptions are some values of relative humidity in B1 and B2 in the spring, and in B1 in winter and summer, which are lower than the minimum humidity (50% according to the standard. b The investigated barns are characterized with poor insulation and do not provide enough isolation from the external ambient temperatures. With the exception of winter, the temperature of the air inside the buildings was lower than that outside, with minor differences for all seasons. The fans in the barns have no effect on the inside air temperature, especially in summer. There was a risk of higher temperatures mainly during the summer period. c There is no significant difference between the average temperatures, air humidity and speed of airflow in all technological zones of the investigated barns. d The largest and statistically significant is the difference between the relative air humidity outside and inside the building in Farm 3, followed by buildings in Farm 1 and 2, where the

Power control of a wind farm with active stall wind turbines and AC grid connection

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Sørensen, Poul; Iov, Florin

both the control on wind turbine level as well as the central control on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power production to the reference power ordered by the operators is assessed and discussed by means of simulations.......This paper describes the design of a centralised wind farm controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection. The overall aim of such controller is to enable the wind farms to provide the best grid support. The designed wind farm control involves...

Self-Management of Social Initiations by Kindergarten Students with Disabilities in the General Education Classroom

Science.gov (United States)

Reynolds, Brooke M.; Gast, David L.; Luscre, Deanna

2014-01-01

The effectiveness of a self-management intervention on social interaction behaviors was evaluated for students with disabilities and social deficits. Four students enrolled in a general education kindergarten classroom were taught to self-monitor social initiations during nonstructured social time via a digital wrist counter. The number of social…

Physics of Prestall Propagating Disturbances in Axial Compressors and Their Potential as a Stall Warning Indicator

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Mario Eck

2017-03-01

Full Text Available Axial compressors in aero engines are prone to suffering a breakdown of orderly flow when operating at the peak of the pressure rise characteristic. The damaging potential of separated flows is why a safe distance has to be left between every possible operating point and an operating point at which stall occurs. During earlier investigations of stall inception mechanisms, a new type of prestall instability has been found. In this study, it could be demonstrated that the prestall instability characterised by discrete flow disturbances can be clearly assigned to the subject of “Rotating Instabilities”. Propagating disturbances are responsible for the rise in blade passing irregularity. If the mass flow is reduced successively, the level of irregularity increases until the prestall condition devolves into rotating stall. The primary objective of the current work is to highlight the basic physics behind these prestall disturbances by complementary experimental and numerical investigations. Before reaching the peak of the pressure rise characteristic flow, disturbances appear as small vortex tubes with one end attached to the casing and the other attached to the suction surface of the rotor blade. These vortex structures arise when the entire tip region is affected by blockage and at the same time the critical rotor incidence is not exceeded in this flow regime. Furthermore, a new stall indicator was developed by applying statistical methods to the unsteady pressure signal measured over the rotor blade tips, thus granting a better control of the safety margin.

Conflict Resolution, Can It Really Make a Difference in the Classroom: Conflict Resolution Strategies for Classroom Teachers

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Pollan, Savannah; Wilson-Younger, Dylinda

2012-01-01

This article discusses conflict and provides five resolutions for teachers on managing negative behaviors within the classroom. Acknowledging and implementing conflict resolution strategies in the classroom enables every student to fully participate in the learning process.

The Prosocial Classroom: Teacher Social and Emotional Competence in Relation to Student and Classroom Outcomes

Science.gov (United States)

Jennings, Patricia A.; Greenberg, Mark T.

2009-01-01

The authors propose a model of the prosocial classroom that highlights the importance of teachers' social and emotional competence (SEC) and well-being in the development and maintenance of supportive teacher-student relationships, effective classroom management, and successful social and emotional learning program implementation. This model…

Self-management as a strategy to improve the classroom behavior of adolescents with ADHD.

Science.gov (United States)

Shapiro, E S; DuPaul, G J; Bradley-Klug, K L

1998-01-01

This article reports on the application of a self-management strategy for improving the classroom behavior of students with attention-deficit/hyperactivity disorder (ADHD). Based on the work of Rhode, Morgan, and Young (1983), the intervention focuses on teaching students to systematically rate their own behavior according to the rating of their teacher. Although, historically, self-management strategies based on cognitive control have not been found to be effective for students with ADHD, strategies based on contingency management have not been widely reported in the literature. A description of the intervention and two case study illustrations are provided. Potential limitations and implications for research in using this strategy are discussed.

Low-Order Modeling of Dynamic Stall on Airfoils in Incompressible Flow

Science.gov (United States)

Narsipur, Shreyas

Unsteady aerodynamics has been a topic of research since the late 1930's and has increased in popularity among researchers studying dynamic stall in helicopters, insect/bird flight, micro air vehicles, wind-turbine aerodynamics, and ow-energy harvesting devices. Several experimental and computational studies have helped researchers gain a good understanding of the unsteady ow phenomena, but have proved to be expensive and time-intensive for rapid design and analysis purposes. Since the early 1970's, the push to develop low-order models to solve unsteady ow problems has resulted in several semi-empirical models capable of effectively analyzing unsteady aerodynamics in a fraction of the time required by high-order methods. However, due to the various complexities associated with time-dependent flows, several empirical constants and curve fits derived from existing experimental and computational results are required by the semi-empirical models to be an effective analysis tool. The aim of the current work is to develop a low-order model capable of simulating incompressible dynamic-stall type ow problems with a focus on accurately modeling the unsteady ow physics with the aim of reducing empirical dependencies. The lumped-vortex-element (LVE) algorithm is used as the baseline unsteady inviscid model to which augmentations are applied to model unsteady viscous effects. The current research is divided into two phases. The first phase focused on augmentations aimed at modeling pure unsteady trailing-edge boundary-layer separation and stall without leading-edge vortex (LEV) formation. The second phase is targeted at including LEV shedding capabilities to the LVE algorithm and combining with the trailing-edge separation model from phase one to realize a holistic, optimized, and robust low-order dynamic stall model. In phase one, initial augmentations to theory were focused on modeling the effects of steady trailing-edge separation by implementing a non-linear decambering

Meeting Student Needs in the Freedom Writers Movie: An Activity in a Classroom Management Course

Science.gov (United States)

Tanase, Madalina

2013-01-01

The study described in this paper explored the understanding pre-service teachers' have of PK-12 student needs (i.e. Belonging, Mastery, Independence, and Generosity) and the importance of meeting these needs in a climate of Invitational Education. 71 undergraduate teacher education candidates enrolled in a Classroom Management course at a…

Lift hysteresis at stall as an unsteady boundary-layer phenomenon

Science.gov (United States)

Moore, Franklin K

1956-01-01

Analysis of rotating stall of compressor blade rows requires specification of a dynamic lift curve for the airfoil section at or near stall, presumably including the effect of lift hysteresis. Consideration of the magnus lift of a rotating cylinder suggests performing an unsteady boundary-layer calculation to find the movement of the separation points of an airfoil fixed in a stream of variable incidence. The consideration of the shedding of vorticity into the wake should yield an estimate of lift increment proportional to time rate of change of angle of attack. This increment is the amplitude of the hysteresis loop. An approximate analysis is carried out according to the foregoing ideas for a 6:1 elliptic airfoil at the angle of attack for maximum lift. The assumptions of small perturbations from maximum lift are made, permitting neglect of distributed vorticity in the wake. The calculated hysteresis loop is counterclockwise. Finally, a discussion of the forms of hysteresis loops is presented; and, for small reduced frequency of oscillation, it is concluded that the concept of a viscous "time lag" is appropriate only for harmonic variations of angle of attack with time at mean conditions other than maximum lift.

Increasing On-Task Behavior in Students in a Regular Classroom: Effectiveness of a Self-Management Procedure Using a Tactile Prompt

NARCIS (Netherlands)

Moore, D.W.; Anderson, A.; Glassenbury, M.; Didden, H.C.M.; Lang, R.B.

2013-01-01

Self-management strategies have been shown to be widely effective. However, limited classroom-based research exists involving low performing but developmentally normal high school-aged participants. This study examined the effectiveness of a self-management strategy aimed at increasing on-task

Increasing In-Service Teacher Implementation of Classroom Management Practices through Consultation, Implementation Planning, and Participant Modeling

Science.gov (United States)

Hagermoser Sanetti, Lisa M.; Williamson, Kathleen M.; Long, Anna C. J.; Kratochwill, Thomas R.

2018-01-01

Numerous evidence-based classroom management strategies to prevent and respond to problem behavior have been identified, but research consistently indicates teachers rarely implement them with sufficient implementation fidelity. The purpose of this study was to evaluate the effectiveness of implementation planning, a strategy involving logistical…

Keeping an Eye on Learning: Differences between Expert and Novice Teachers' Representations of Classroom Management Events

Science.gov (United States)

Wolff, Charlotte E.; van den Bogert, Niek; Jarodzka, Halszka; Boshuizen, Henny P. A.

2015-01-01

Classroom management represents an important skill and knowledge set for achieving student learning gains, but poses a considerable challenge for beginning teachers. Understanding how teachers' cognition and conceptualizations differ between experts and novices is useful for enhancing beginning teachers' expertise development. We created a coding…

MICROBIOLOGICAL STUDY ON ICE FROM A FISH STALL

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E. Tirloni

2012-08-01

Full Text Available The ice used for exposure of fish products could be a source of secondary contamination due to ice machine, due to not respected good manufacturing practices, particularly when ice is left on the fish stall and the next day the new layer is deposited over the old one. Aim of this study was the verification of the hygienic risk of this procedure through analyses of the liquid produced by the zones “thawed cephalopods” and “fresh whole fish”. Almost the microorganisms found were Gram negative (in particular Pseudomonadaceae.

An automatic system for the detection of dairy cows lying behaviour in free-stall barns

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Simona M.C. Porto

2013-09-01

Full Text Available In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF, the miss factor (MF, the sensitivity, and the quality percentage (QP. The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

Inviscid double wake model for stalled airfoils

International Nuclear Information System (INIS)

Marion, L; Ramos-García, N; Sørensen, J N

2014-01-01

An inviscid double wake model based on a steady two-dimensional panel method has been developed to predict aerodynamic loads of wind turbine airfoils in the deep stall region. The separated flow is modelled using two constant vorticity sheets which are released at the trailing edge and at the separation point. A calibration of the code through comparison with experiments has been performed using one set of airfoils. A second set of airfoils has been used for the validation of the calibrated model. Predicted aerodynamic forces for a wide range of angles of attack (0 to 90 deg) are in overall good agreement with wind tunnel measurements

Evaluation Comparison of Online and Classroom Instruction for HEPE 129--Fitness and Lifestyle Management Course.

Science.gov (United States)

Davies, Randall S.; Mendenhall, Robert

This evaluation compared online (i.e., World Wide Web-based) and classroom instructional delivery methods for the Health Education/Physical Education course, "Fitness and Lifestyle Management," at Brigham Young University (Utah). The results of the study were intended to add to the discussion on the value of web-based courses as a means…

Zonal RANS/LES coupling simulation of a transitional and separated flow around an airfoil near stall

Energy Technology Data Exchange (ETDEWEB)

Richez, F.; Mary, I.; Gleize, V. [ONERA, Department of Computational Fluid Dynamics and Aeroacoustics, 29 Avenue de la Division Leclerc, BP 72, Chatillon (France); Basdevant, C. [Universite Paris-Nord, Laboratoire d' Analyse, Geometrie et Applications, CNRS, Villetaneuse (France)

2008-05-15

The objective of the current study is to examine the course of events leading to stall just before its occurrence. The stall mechanisms are very sensitive to the transition that the boundary layer undergoes near the leading edge of the profile by a so-called laminar separation bubble (LSB). In order to provide helpful insights into this complex flow, a zonal Reynolds-averaged Navier-Stokes (RANS)/large-eddy simulation (LES) simulation of the flow around an airfoil near stall has been achieved and its results are presented and analyzed in this paper. LSB has already been numerically studied by direct numerical simulation (DNS) or LES, but for a flat plate with an adverse pressure gradient only. We intend, in this paper, to achieve a detailed analysis of the transition process by a LSB in more realistic conditions. The comparison with a linear instability analysis has shown that the numerical instability mechanism in the LSB provides the expected frequency of the perturbations. Furthermore, the right order of magnitude for the turbulence intensities at the reattachment point is found. (orig.)

The Effectiveness of Rule-Governed Democracy Classroom Management Style on Self-Esteem of 3rd-grade High School Male Students

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H. Nazari

2015-06-01

Full Text Available By utilizing classroom management styles, teachers will be able to get rid of possible students’ misconducts and promote a friendly atmosphere which will in effect promote students’ participation in learning activities. Additionally, increased self-esteem, which is an achievement of such utilization, will influence various aspects of students’ future lives. Taking this point into consideration, the present study aimed at determining the efficacy of rule-governed democracy classroom management style on self-esteem of 3rd-grade high-school male students. All 3rd-grade high-school male students of Abdanan city in the academic year 2013 comprised the statistical population to this study. Using convenience sampling, 38 subjects were selected and randomly assigned to experimental and control groups. The research design was pretest-post-test. Cooper Smith's self-esteem questionnaire was used as the research instrument which was administered to the two groups at the outset. The experimental group was given seven 90-minutes sessions of treatment and twice-a-week. The two groups were asked to fill out the same questionnaire for the post-test stage afterwards. Descriptive statistics, including the analysis of covariance was used to analyze the data. The results revealed that the utilization of rule-governed democracy classroom management style in the classroom had significantly increased the self-esteem (public-family-social- and scholastic-professional of male students in the post-test (p<0/001.

Suppression of inducer stall based on inlet recirculation in a centrifugal impeller. 1st Report. Improvement in stall limit by ring groove arrangement; Enshin haneguruma iriguchi junkanryu ni yoru inducer shissoku no yokusei. 1. kanjoko ni yoru shissoku genkai no kaizen

Energy Technology Data Exchange (ETDEWEB)

Ueki, H.; Ishida, M.; Sakaguchi, D.; Sun, Z. [Nagasaki University, Nagasaki (Japan). Faculty of Engineering

2000-07-25

A ring groove arrangement is proposed to suppress unstable flow or surge in a centrifugal blower. The ring groove arrangement connects the upstream position of impeller inlet and the inducer throat tip through a bypass. The recirculation flow 'vas formed by the pressure difference between the two positions, and the recirculation flow rate was changed by increasing the ring groove widths. The inlet recirculation results in a decrease in the flow rate of unstable flow inception, and an up to 800 improvement in stall limit was obtained by the ring groove arrangement at a small expense of the delivery pressure drop. The improvement of stall limit in the present experiment seems to be mainly due to decrease in flow incidence based on the inlet recirculation flow. Tre flow incidence decreases more as the recirculation flow rate increases, thus resulting in a larger improvement in stall limit. (author)

Recognizing the Centrality of Emotion in Diversity Courses: Commentary on "Gender in the Management Education Classroom"

Science.gov (United States)

Spelman, Duncan

2010-01-01

This commentary adds to the analysis and recommendations presented in "Gender in the Management Education Classroom" concerning a very challenging incident focused on powerful gender/diversity dynamics. It discusses the centrality of emotion in students' experiences of diversity discussions and calls for teachers to explicitly help students…

Refugee-Teacher-Train-Refugee-Teacher Intervention Research in Malaysia: Promoting Classroom Management and Teacher Self-Care

Science.gov (United States)

O'Neal, Colleen R.; Gosnell, Nicole M.; Ng, Wai Sheng; Ong, Edward

2018-01-01

Given the current refugee crisis, the development of sustainable postconflict refugee education systems and supports is essential. The present study reports Resilient Refugee Education (RRE) intervention effects on refugee teacher confidence and knowledge of classroom management, in addition to refugee teacher self-care in Malaysia. We compared…

Illustrating the multiple facets and levels of fidelity of implementation to a teacher classroom management intervention.

Science.gov (United States)

Reinke, Wendy M; Herman, Keith C; Stormont, Melissa; Newcomer, Lori; David, Kimberly

2013-11-01

Many school-based interventions to promote student mental health rely on teachers as implementers. Thus, understanding the interplay between the multiple domains of fidelity to the intervention and intervention support systems such as coaching and teacher implementation of new skills is an important aspect of implementation science. This study describes a systematic process for assessing multiple domains of fidelity. Data from a larger efficacy trial of the Incredible Years Teacher Classroom Management (IY TCM) program are utilized. Data on fidelity to the IY TCM workshop training sessions and onsite weekly coaching indicate that workshop leaders and the IY TCM coach implemented the training and coaching model with adequate adherence. Further, workshop leaders' ratings of engagement were associated with teacher implementation of specific praise, following training on this content. Lastly, the IY TCM coach differentiation of teacher exposure to coaching was evaluated and found to be associated with teacher implementation of classroom management practices and student disruptive behavior.

Teacher Perceptions of the Impact of Self-Efficacy on Classroom Management Style: A Case Study

Science.gov (United States)

McCain, Patty Jo

2017-01-01

The purpose of this qualitative case study was to develop an understanding of how current and former middle school teachers in a suburban school district in northeast Georgia perceive low self-efficacy impacts their classroom management style. The theory guiding this study was Bandura's (1977) self-efficacy theory as it supported the idea that…

A Beddoes-Leishman type dynamic stall model in state-space and indicial formulations

DEFF Research Database (Denmark)

Hansen, M.H.; Gaunaa, Mac; Aagaard Madsen, Helge

2004-01-01

This report contains a description of a Beddoes-Leishman type dynamic stall model in both a state-space and an indicial function formulation. The model predicts the unsteady aerodynamic forces and moment on an airfoil section undergoing arbitrary motionin heave, lead-lag, and pitch. The model...... features, such as overshoot of the lift, in the stall region. The linearized model is shown to give identicalresults to the full model for small amplitude oscillations. Furthermore, it is shown that the response of finite thichkness airfoils can be reproduced to a high accuracy by the use of specific...... is carried out by comparing the response of the model with inviscid solutions and observing the general behavior of the model using known airfoil data as input. Theproposed dynamic model gives results identical to inviscid solutions within the attached-flow region; and it exhibits the expected dynamic...

Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

DEFF Research Database (Denmark)

Chen, Yun; Jørgensen, Mette; Kolde, Raivo

2011-01-01

of RNAPII stalling. CONCLUSIONS: In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data....... strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. RESULTS: Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII...... of these four marks are found to be necessary for recruitment of RNAPII but not sufficient for the elongation. We also show that the spatial distributions of histone marks are almost as predictive as the signal strength and that a set of histone marks immediately downstream of the TSS is highly predictive...

Progression in Complexity: Contextualizing Sustainable Marine Resources Management in a 10th Grade Classroom

Science.gov (United States)

Bravo-Torija, Beatriz; Jiménez-Aleixandre, María-Pilar

2012-01-01

Sustainable management of marine resources raises great challenges. Working with this socio-scientific issue in the classroom requires students to apply complex models about energy flow and trophic pyramids in order to understand that food chains represent transfer of energy, to construct meanings for sustainable resources management through discourse, and to connect them to actions and decisions in a real-life context. In this paper we examine the process of elaboration of plans for resources management in a marine ecosystem by 10th grade students (15-16 year) in the context of solving an authentic task. A complete class ( N = 14) worked in a sequence about ecosystems. Working in small groups, the students made models of energy flow and trophic pyramids, and used them to solve the problem of feeding a small community for a long time. Data collection included videotaping and audiotaping of all of the sessions, and collecting the students' written productions. The research objective is to examine the process of designing a plan for sustainable resources management in terms of the discursive moves of the students across stages in contextualizing practices, or different degrees of complexity (Jiménez-Aleixandre & Reigosa International Journal of Science Education, 14(1): 51-61 2006), understood as transformations from theoretical statements to decisions about the plan. The analysis of students' discursive moves shows how the groups progressed through stages of connecting different models, between them and with the context, in order to solve the task. The challenges related to taking this sustainability issue to the classroom are discussed.

A Cross-Cultural Study of Students' Behaviors and Classroom Management Strategies in the USA and Korea

Science.gov (United States)

Shin, Sunwoo; Koh, Myung-sook

2008-01-01

The purpose of this cross-cultural study is to investigate comparative students' problem behaviors and classroom behavior management strategies for students in urban public schools between teachers in the United States and Korea. This study incorporated data collected from two different teacher self-reported survey questionnaires, the Student…

A Study to Determine the Effectiveness of a Positive Approach to Discipline System for Classroom Management.

Science.gov (United States)

Allen, Sherwin

To test the effectiveness of the Positive Approach to Discipline (PAD) System of classroom management, this study examined changes in the incidence of administrative disciplinary referrals, corporal punishment, and school suspensions in an urban Southwest public middle school. The 13-step PAD procedure--incorporating counseling, problem-solving,…

Numerical simulation of the RISOe1-airfoil dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Bertagnolio, F.; Soerensen, N. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

1997-12-31

In this paper we are concerned with the numerical computation of the dynamic stall that occur in the viscous flowfield over an airfoil. These results are compared to experimental data that were obtained with the new designed RISOe1-airfoil, both for a motionless airfoil and for a pitching motion. Moreover, we present some numerical computations of the plunging and lead-lag motions. We also investigate the possibility of using the pitching motion to simulate the plunging and lead-lag situations. (au)

Evaluation of a "Flipped Classroom" Approach in Management Education

Science.gov (United States)

Bergfjord, Ole Jakob; Heggernes, Tarjei

2016-01-01

In this paper, a "flipped classroom" approach is evaluated using three different datasets. We use student evaluations of the "flipped classroom" in particular, in addition to regular course evaluations and exam results for the past three years in order to allow for statistical comparisons. Overall, the results are quite…

Self-Regulated Assignment Attack Strategy: Evaluating the Effects of a Classroom-Level Intervention on Student Management of Curricular Activities in a Resource Context

Science.gov (United States)

Ness, Bryan M.; Sohlberg, McKay Moore

2013-01-01

The purpose of this study was to evaluate the impact of a classroom-based strategy instruction package grounded in self-regulated learning. The Self-Regulated Assignment Attack Strategy (SAAS) targeted self-regulation of assignment management and related academic-behavioral variables for 6th grade students in resource support classrooms. SAAS was…

Preliminary Results of the Determination of Inlet-Pressure Distortion Effects on Compressor Stall and Altitude Operating Limits of the J57-P-1 Turbojet Engine

Science.gov (United States)

Wallner, L. E.; Lubick, R. J.; Chelko, L. J.

1955-01-01

During an investigation of the J57-P-1 turbojet engine in the Lewis altitude wind tunnel, effects of inlet-flow distortion on engine stall characteristics and operating limits were determined. In addition to a uniform inlet-flow profile, the inlet-pressure distortions imposed included two radial, two circumferential, and one combined radial-circumferential profile. Data were obtained over a range of compressor speeds at an altitude of 50,000 and a flight Mach number of 0.8; in addition, the high- and low-speed engine operating limits were investigated up to the maximum operable altitude. The effect of changing the compressor bleed position on the stall and operating limits was determined for one of the inlet distortions. The circumferential distortions lowered the compressor stall pressure ratios; this resulted in less fuel-flow margin between steady-state operation and compressor stall. Consequently, the altitude operating Limits with circumferential distortions were reduced compared with the uniform inlet profile. Radial inlet-pressure distortions increased the pressure ratio required for compressor stall over that obtained with uniform inlet flow; this resulted in higher altitude operating limits. Likewise, the stall-limit fuel flows required with the radial inlet-pressure distortions were considerably higher than those obtained with the uniform inlet-pressure profile. A combined radial-circumferential inlet distortion had effects on the engine similar to the circumferential distortion. Bleeding air between the two compressors eliminated the low-speed stall limit and thus permitted higher altitude operation than was possible without compressor bleed.

The SmpB C-terminal tail helps tmRNA to recognize and enter stalled ribosomes

Directory of Open Access Journals (Sweden)

Mickey R. Miller

2014-09-01

Full Text Available In bacteria, transfer-messenger RNA (tmRNA and SmpB comprise the most common and effective system for rescuing stalled ribosomes. Ribosomes stall on mRNA transcripts lacking stop codons and are rescued as the defective mRNA is swapped for the tmRNA template in a process known as trans-translation. The tmRNA–SmpB complex is recruited to the ribosome independent of a codon–anticodon interaction. Given that the ribosome uses robust discriminatory mechanisms to select against non-cognate tRNAs during canonical decoding, it has been hard to explain how this can happen. Recent structural and biochemical studies show that SmpB licenses tmRNA entry through its interactions with the decoding center and mRNA channel. In particular, the C-terminal tail of SmpB promotes both EFTu activation and accommodation of tmRNA, the former through interactions with 16S rRNA nucleotide G530 and the latter through interactions with the mRNA channel downstream of the A site. Here we present a detailed model of the earliest steps in trans-translation, and in light of these mechanistic considerations, revisit the question of how tmRNA preferentially reacts with stalled, non-translating ribosomes.

Replisome stall events have shaped the distribution of replication origins in the genomes of yeasts

Science.gov (United States)

Newman, Timothy J.; Mamun, Mohammed A.; Nieduszynski, Conrad A.; Blow, J. Julian

2013-01-01

During S phase, the entire genome must be precisely duplicated, with no sections of DNA left unreplicated. Here, we develop a simple mathematical model to describe the probability of replication failing due to the irreversible stalling of replication forks. We show that the probability of complete genome replication is maximized if replication origins are evenly spaced, the largest inter-origin distances are minimized, and the end-most origins are positioned close to chromosome ends. We show that origin positions in the yeast Saccharomyces cerevisiae genome conform to all three predictions thereby maximizing the probability of complete replication if replication forks stall. Origin positions in four other yeasts—Kluyveromyces lactis, Lachancea kluyveri, Lachancea waltii and Schizosaccharomyces pombe—also conform to these predictions. Equating failure rates at chromosome ends with those in chromosome interiors gives a mean per nucleotide fork stall rate of ∼5 × 10−8, which is consistent with experimental estimates. Using this value in our theoretical predictions gives replication failure rates that are consistent with data from replication origin knockout experiments. Our theory also predicts that significantly larger genomes, such as those of mammals, will experience a much greater probability of replication failure genome-wide, and therefore will likely require additional compensatory mechanisms. PMID:23963700

Disruption of PCNA-lamins A/C interactions by prelamin A induces DNA replication fork stalling.

Science.gov (United States)

Cobb, Andrew M; Murray, Thomas V; Warren, Derek T; Liu, Yiwen; Shanahan, Catherine M

2016-09-02

The accumulation of prelamin A is linked to disruption of cellular homeostasis, tissue degeneration and aging. Its expression is implicated in compromised genome stability and increased levels of DNA damage, but to date there is no complete explanation for how prelamin A exerts its toxic effects. As the nuclear lamina is important for DNA replication we wanted to investigate the relationship between prelamin A expression and DNA replication fork stability. In this study we report that the expression of prelamin A in U2OS cells induced both mono-ubiquitination of proliferating cell nuclear antigen (PCNA) and subsequent induction of Pol η, two hallmarks of DNA replication fork stalling. Immunofluorescence microscopy revealed that cells expressing prelamin A presented with high levels of colocalisation between PCNA and γH2AX, indicating collapse of stalled DNA replication forks into DNA double-strand breaks. Subsequent protein-protein interaction assays showed prelamin A interacted with PCNA and that its presence mitigated interactions between PCNA and the mature nuclear lamina. Thus, we propose that the cytotoxicity of prelamin A arises in part, from it actively competing against mature lamin A to bind PCNA and that this destabilises DNA replication to induce fork stalling which in turn contributes to genomic instability.

Visualization by PIV of dynamic stall on a vertical axis wind turbine

NARCIS (Netherlands)

Ferreira, C.J.S.; Kuik, van G.A.M.; Bussel, van G.J.W.; Scarano, F.

2009-01-01

The aerodynamic behavior of a vertical axis wind turbine (VAWT) is analyzed by means of 2D particle image velocimetry (PIV), focusing on the development of dynamic stall at different tip speed ratios. The VAWT has an unsteady aerodynamic behavior due to the variation with the azimuth angle ¿ of the

ORIGINAL ARTICLE An Assessment of Mathematics Classroom ...

African Journals Online (AJOL)

Bdu

ORIGINAL ARTICLE. An Assessment of Mathematics Classroom Teaching- ... the study was to assess whether the learning classroom environment was compliant with constructivism. ... of our education system. Applefield ... share control of the design, management, and evaluation ..... development of formative assessment.

Personalities in the Classroom: Making the Most of Them

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Richardson, Rita Coombs; Arker, Emily

2010-01-01

Teachers' personality traits are reflected in their classroom instruction--especially in their selection of various instructional strategies, the materials they choose, and their classroom management techniques. Moreover, personality styles are positively interrelated with learning styles as well as teaching styles. In many classrooms, however,…

Ethnic Dimensions of Guatemala's Stalled Transition: A Parity-Specific Analysis of Ladino and Indigenous Fertility Regimes.

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Grace, Kathryn; Sweeney, Stuart

2016-02-01

In some contemporary populations, fertility levels appear to plateau, with women maintaining a consistently high level of fertility for a relatively extended period. Because this plateau does not reflect the historical patterns observed in Europe, the focus of most studies on fertility patterns, mechanisms underlying the plateau and the reinstatement of a decline have not been fully explored and are not fully understood. Through the construction of fertility histories of 25,000 women using multiple years of health survey data, we analyze some of the components of stalled fertility as they pertain to Guatemala, the only Central American country to have experienced a stalled fertility decline.

Associations of soft flooring materials in free stalls with milk yield, clinical mastitis, teat lesions, and removal of dairy cows.

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Ruud, L E; Bøe, K E; Osterås, O

2010-04-01

The objective was to test if there was an association between free-stall base softness and milk yield, incidence of clinical mastitis (CM), teat lesions, and removal of cows. In a questionnaire sent to 1,923 dairy farms presumed to be using free-stall housing, farmers were asked for information regarding housing and stall base; for example, the year of installation and the product name or brand of their mats or mattresses. This information was merged with data for milk yield, CM, teat lesions, and removal of cows extracted from the Norwegian Dairy Herd Recording System for the years after installation of mats or mattresses. After exclusion of invalid contributions, the data set consisted of 29,326 lactations for milk yield distributed over 363 free-stalled herds in Norway. The farms were stratified into 5 categories according to the softness of the stall surface measured as millimeter impact of a sphere with a diameter of 120 mm at 2-kN load: 1=concrete, softness of 0mm; 2=rubber, softness of 1 to 8mm; 3=soft mats, softness of 9 to 16 mm; 4=multilayer mats, softness of 17 to 24 mm; and 5=mattresses, softness over 24 mm. Lactation curves were estimated as modified Wood's lactation curves using test-day data and mixed models with repeated measurements, adjusting for days in milk, parity, and softness of free-stall flooring. Herds on concrete free-stall bases yielded 6,727+/-146 kg of milk from 5 to 305 days in milk. In comparison, herds showed a decrease of 0.3% on rubber, an increase of 2.4% on soft mats, an increase of 4.5% on multilayer mats, and an increase of 3.9% on mattresses. Compared with concrete, the hazard ratio (HR) of CM was less on rubber, multilayer mats, and mattresses [HR=0.89 (0.79-0.99), 0.85 (0.73-0.996), and 0.80 (0.73-0.88), respectively]. Compared with concrete, the HR of teat lesions was less on rubber, soft mats, multilayer mats, and mattresses [HR=0.41 (0.26-0.65), 0.33 (0.24-0.44), 0.12 (0.04-0.38), and 0.47 (0.33-0.67), respectively]. The

Stall Recovery in a Centrifuge-Based Flight Simulator With an Extended Aerodynamic Model

NARCIS (Netherlands)

Ledegang, W.D.; Groen, E.L.

2015-01-01

We investigated the performance of 12 airline pilots in recovering from an asymmetrical stall in a flight simulator featuring an extended aerodynamic model of a transport-category aircraft, and a centrifuge-based motion platform capable of generating enhanced buffet motion and g-cueing. All pilots

Academic Practices to Gain and Maintain Student-Teacher Connectedness and Classroom Behavioral Management, Related to Educator Demographics

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Kendall, Leslie Threadgill

2015-01-01

Connectedness and classroom management has been defined as the ability to relate to students and keep order and maintain successful relationships with individuals. This qualitative study utilized surveys, questionnaires, interviews, and observations to examine the best practices implemented by educators to develop and maintain connections with…

Classroom Management and National Professional Standards for Teachers: A Review of the Literature on Theory and Practice

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Egeberg, Helen M.; McConney, Andrew; Price, Anne

2016-01-01

This article reviews the conceptual and empirical research on classroom management to ascertain the extent to which there is consistency between the "advice" found in the research literature and the professional standards for teachers and initial teacher education, in regards to knowledge and perspectives about effective classroom…

Classroom Management Strategies of Highly Effective Teachers in Diverse Middle Schools: Be Strict and Calm, Not Mean

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McGregor, Katheryne L.

2012-01-01

This qualitative research study investigated and identified the classroom management strategies of 12 highly effective middle school teachers who served diverse student populations at two different school sites. In addition, this research explored the beliefs and experiences of 305 diverse middle school students regarding their experiences with…

Teacher Progress Monitoring of Instructional and Behavioral Management Practices: An Evidence-Based Approach to Improving Classroom Practices

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Reddy, Linda A.; Dudek, Christopher M.

2014-01-01

In the era of teacher evaluation and effectiveness, assessment tools that identify and monitor educators' instruction and behavioral management practices are in high demand. The Classroom Strategies Scale (CSS) Observer Form is a multidimensional teacher progress monitoring tool designed to assess teachers' usage of instructional and behavioral…

Critical 23S rRNA interactions for macrolide-dependent ribosome stalling on the ErmCL nascent peptide chain.

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Koch, Miriam; Willi, Jessica; Pradère, Ugo; Hall, Jonathan; Polacek, Norbert

2017-06-20

The nascent peptide exit tunnel has recently been identified as a functional region of ribosomes contributing to translation regulation and co-translational protein folding. Inducible expression of the erm resistance genes depends on ribosome stalling at specific codons of an upstream open reading frame in the presence of an exit tunnel-bound macrolide antibiotic. The molecular basis for this translation arrest is still not fully understood. Here, we used a nucleotide analog interference approach to unravel important functional groups on 23S rRNA residues in the ribosomal exit tunnel for ribosome stalling on the ErmC leader peptide. By replacing single nucleobase functional groups or even single atoms we were able to demonstrate the importance of A2062, A2503 and U2586 for drug-dependent ribosome stalling. Our data show that the universally conserved A2062 and A2503 are capable of forming a non-Watson-Crick base pair that is critical for sensing and transmitting the stalling signal from the exit tunnel back to the peptidyl transferase center of the ribosome. The nucleobases of A2062, A2503 as well as U2586 do not contribute significantly to the overall mechanism of protein biosynthesis, yet their elaborate role for co-translational monitoring of nascent peptide chains inside the exit tunnel can explain their evolutionary conservation. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Classroom Organization: A Key to Successful Management.

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Guernsey, Marsha A.

1989-01-01

Suggestions are presented to increase the special education teacher's organizational efficiency, focusing on instructional planning and use of time and space as they relate to classroom organization. (JDD)

Microbiological quality of air in free-range and box-stall stable horse keeping systems.

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Wolny-Koładka, Katarzyna

2018-04-07

The aim of this study was to assess the microbiological quality of air in three horse riding centers differing in the horse keeping systems. The air samples were collected in one facility with free-range horse keeping system and two with box stalls of different sizes. The samples were collected over a period of 3 years (2015-2017), four times per year (spring, summer, autumn, winter) to assess the effect of seasonal changes. The prevalence of aerobic mesophilic bacteria, mold fungi, actinomycetes, Staphylococcus spp., and Escherichia coli was determined by the air collision method on Petri dishes with appropriate microbiological media. At the same time, air temperature, relative humidity, and particulate matter concentration (PM 10 , PM 2.5 ) were measured. It was found that the horse keeping system affects the occurrence of the examined airborne microorganisms. Over the 3-year period of study, higher temperature and humidity, as well as particulate matter concentration-which notoriously exceeded limit values-were observed in the facilities with the box-stall system. The air sampled from the largest horse riding center, with the largest number of horses and the box-stall system of horse keeping, was also characterized by the heaviest microbiological contamination. Among others, bacteria from the following genera: Staphylococcus spp., Streptococcus spp., Bacillus spp., and E. coli and fungi from the genera Aspergillus, Fusarium, Mucor, Rhizopus, Penicillium, Trichothecium, Cladosporium, and Alternaria were identified in the analyzed samples.

Why Do Promising Therapies Stall in Development and How Can We Move Them Forward?

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Wegner, Craig D; Goodwin, Andrew; Cook, Jon C; Allamneni, Krishna; Sohn, Jane; McVean, Maralee

There are many reasons that molecules fail to progress to market and various principles of risk-benefit decisions that can help drive the molecule through development. This symposium included discussions on global strategies involved in pushing promising molecules to market, what to do when a molecule stalls in its progress to market, and options for rescuing the molecule and pushing it forward again. Innovative partnerships that bring stalled drugs back into clinical development were also addressed. A regulatory perspective on common reasons for a molecule to fail in its forward progress was presented. In addition, situations arise when a third-party advisory committee can provide input to help overcome issues identified by a regulatory agency. Using examples from the private and public domain, presentations centered on how to repurpose a molecule and when more science is needed.

Cooling systems of the resting area in free stall dairy barn

Science.gov (United States)

Calegari, F.; Calamari, L.; Frazzi, E.

2016-04-01

A study during the summer season evaluated the effect of different cooling systems on behavioral and productive responses of Italian Friesian dairy cows kept in an experimental-free stall barn located in the Po Valley in Italy. The study involved 30 lactating dairy cows subdivided into two groups kept in two pens with external hard court paddock in each free stall. The same cooling system was applied in the feeding area in both pens. A different cooling system in the resting area was applied to the two pens: in the pen SW, the resting area was equipped with fans and misters; in the other, there was simple ventilation (SV). Breathing rate, rectal temperature, milk yield, and milk characteristics (fat, protein, and somatic cell count) were measured. Behavioral activities (standing and lying cows in the different areas, as well as the animals in the feed bunk) were recorded. Mild to moderate heat waves during the trial were observed. On average, the breathing rate was numerically greater in SV compared with SW cows (60.2 and 55.8 breath/min, respectively), and mean rectal temperature remained below 39 °C in both groups during the trial (on average 38.7 and 38.8 °C in SV and SW, respectively. During the hotter periods of the trial, the time spent lying indoor in the free stall was greater in SW (11.8 h/day) than SV (10.7 h/day). Conversely, the time spent standing indoor without feeding was greater in SV (4.3 h/day) than SW (3.8 h/day). Milk yield was slightly better maintained during hotter period in SW compared with SV and somatic cell count was also slightly greater in the former. In conclusion, the adoption of the cooling system by means of evaporative cooling also in the resting area reduces the alteration of time budget caused by heat stress.

Analysis of the Unsteady Flow Field in a Centrifugal Compressor from Peak Efficiency to Near Stall with Full-Annulus Simulations

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Yannick Bousquet

2014-01-01

Full Text Available This study concerns a 2.5 pressure ratio centrifugal compressor stage consisting of a splittered unshrouded impeller and a vaned diffuser. The aim of this paper is to investigate the modifications of the flow structure when the operating point moves from peak efficiency to near stall. The investigations are based on the results of unsteady three-dimensional simulations, in a calculation domain comprising all the blade. A detailed analysis is given in the impeller inducer and in the vaned diffuser entry region through time-averaged and unsteady flow field. In the impeller inducer, this study demonstrates that the mass flow reduction from peak efficiency to near stall leads to intensification of the secondary flow effects. The low momentum fluid accumulated near the shroud interacts with the main flow through a shear layer zone. At near stall condition, the interface between the two flow structures becomes unstable leading to vortices development. In the diffuser entry region, by reducing the mass flow, the high incidence angle from the impeller exit induces a separation on the diffuser vane suction side. At near stall operating point, vorticity from the separation is shed into vortex cores which are periodically formed and convected downstream along the suction side.

The effect of training on teachers' knowledge of effective classroom ...

African Journals Online (AJOL)

The effect of training on teachers' knowledge of effective classroom management strategies in Jos metropolis. ... Global Journal of Educational Research ... A single group pre-post test design was used, with a one-day training on classroom management techniques as the independent variable and the number of strategies ...

Miscoding-induced stalling of substrate translocation on the bacterial ribosome.

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Alejo, Jose L; Blanchard, Scott C

2017-10-10

Directional transit of the ribosome along the messenger RNA (mRNA) template is a key determinant of the rate and processivity of protein synthesis. Imaging of the multistep translocation mechanism using single-molecule FRET has led to the hypothesis that substrate movements relative to the ribosome resolve through relatively long-lived late intermediates wherein peptidyl-tRNA enters the P site of the small ribosomal subunit via reversible, swivel-like motions of the small subunit head domain within the elongation factor G (GDP)-bound ribosome complex. Consistent with translocation being rate-limited by recognition and productive engagement of peptidyl-tRNA within the P site, we now show that base-pairing mismatches between the peptidyl-tRNA anticodon and the mRNA codon dramatically delay this rate-limiting, intramolecular process. This unexpected relationship between aminoacyl-tRNA decoding and translocation suggests that miscoding antibiotics may impact protein synthesis by impairing the recognition of peptidyl-tRNA in the small subunit P site during EF-G-catalyzed translocation. Strikingly, we show that elongation factor P (EF-P), traditionally known to alleviate ribosome stalling at polyproline motifs, can efficiently rescue translocation defects arising from miscoding. These findings help reveal the nature and origin of the rate-limiting steps in substrate translocation on the bacterial ribosome and indicate that EF-P can aid in resuming translation elongation stalled by miscoding errors.

Unsteady performance of a cavitating hydrofoil in stall conditions. Shissoku jotai ni okeru yokukei no hiteijo tokusei

Energy Technology Data Exchange (ETDEWEB)

Ogata, H. (Tohoku University, Sendai (Japan)); Ito, Y. (Hachinoe Institutea of Technology, Aomori (Japan)); Oba, R. (Tohoku University, Sendai (Japan). Institute of Fluid Science); Sunayama, Y.; Abe, J. (Suzuki Co. Ltd., Shizuoka (Japan))

1991-11-25

To elucidate the unsteady performance of cavitating hydrofoils in a stall condition, this paper describes a survey on unsteady conditions without cavitations and stall conditions as to their characteristics from a cavitation to a supercavitation, lift and drag. Flows with cavitations were also analyzed. As a result of comparing also data for the subcavitation regions, it was found that a large-scale vortex generation on the hydrofoil back-pressure plane in near stall condition has a close relation with the changes in lifts and drags or the cavitation breakdown. The experiment used a testing water tank of circulation flow type having a rectangular measuring cross section (70 mm in width and 190 mm in height), and the hydrofoil specimens of two-dimensional symmetric type with a chord length of 70 mm and an aspect ratio of 1.0. The test condition used a cavitation coefficient of 0.18-6.33 (from a supercavitation to non-cavitation). A numerical analysis proved that the power spectra around the hydrofoils having no cavitations agreed with the experimental results, and verified the reasonability of the application. 18 refs., 8 figs., 2 tabs.

A Comparative Study of Elementary Teachers' Beliefs and Strategies on Classroom and Behavior Management in the USA and Korean School Systems

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Koh, Myung-sook; Shin, Sunwoo

2014-01-01

The purpose of this cross-cultural study is to investigate elementary teachers' beliefs and inter-cultural perspectives in classroom management (instructional environment and behavior management) for students in public schools of the U.S. and Korea. The results supported that the two groups of teachers showed similar beliefs in instructional…

Wave energy plants: Control strategies for avoiding the stalling behaviour in the Wells turbine

Energy Technology Data Exchange (ETDEWEB)

Amundarain, Modesto; Alberdi, Mikel; Garrido, Aitor J.; Garrido, Izaskun; Maseda, Javier [Dept. of Automatic Control and Systems Engineering, EUITI Bilbao, University of the Basque Country, Plaza de la Casilla 3, 48012 Bilbao (Spain)

2010-12-15

This study analyzes the problem of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose two different control strategies are presented and compared. In the first one, a rotational speed control system is employed to appropriately adapt the speed of the double-fed induction generator coupling to the turbine, according to the pressure drop entry. In the second control strategy, an airflow control regulates the power generated by the turbine generator module by means of the modulation valve avoiding the stalling behaviour. It is demonstrated that the proposed rotational speed control design adequately matches the desired relationship between the slip of the double-fed induction generator and the pressure drop input, whilst the valve control using a traditional PID controller successfully governs the flow that modulates the pressure drop across the turbine. (author)

A Detailed Study of the Rotational Augmentation and Dynamic Stall Phenomena for Wind Turbines

DEFF Research Database (Denmark)

Guntur, Srinivas

This thesis presents investigations into the aerodynamics of wind turbine rotors, with a focus on the in-board sections of the rotor. Two important aerodynamic phenomena that have challenged scientists over nearly the last half a century are the so-called rotational augmentation and dynamic stall....... This thesis presents an investigation into these two phenomena, using data from the MEXICO and the NREL UAE Phase VI experiments, as well as data obtained from full rotor CFD computations carried out using the in-house flow solver Ellipsys3D. The experimental data, CFD data and that from some of the existing...... on wind turbine blades using the N-sequence data of the NREL UAE Phase VI experiment. The experimental data is compared with the results from unsteady Delayed Detached Eddy Simulations (DDES). The same conditions are also modelled using a Beddoes-Leishman type dynamic stall model by Hansen et al. (2004...

Managing Student Behavior in an Elementary School Music Classroom: A Study of Class-Wide Function-Related Intervention Teams

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Caldarella, Paul; Williams, Leslie; Jolstead, Krystine A.; Wills, Howard P.

2017-01-01

Classroom management is a common concern for teachers. Music teachers in particular experience unique behavior challenges because of large class sizes, uncommon pacing requirements, and performance-based outcomes. Positive behavior support (PBS) is an evidence-based framework for preventing or eliminating challenging behaviors by teaching and…

Classroom Management Training for Teachers in Urban Environments Serving Predominately African American Students: A Review of the Literature

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Larson, Kristine E.

2016-01-01

The purpose of this paper was to review the literature in terms of professional development activities that researchers have enlisted to reduce student problem behaviors and improve classroom management competencies among teachers who work in urban environments serving predominately African American students. First, the author conducted a…

Computer modeling of the stalled flow of a rotating cylinder and the reverse magnus effect

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Belotserkovskii, S. M.; Kotovskii, V. N.; Nisht, M. I.; Fedorov, R. M.

1985-02-01

Unsteady stalled flow around a rotating cylinder is investigated in a numerical experiment. Attention is mostly given to the reverse Magnus effect which was discovered in tube experiments at some critical rotational speed of the cylinder.

Guerrilla Video: A New Protocol for Producing Classroom Video

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Fadde, Peter; Rich, Peter

2010-01-01

Contemporary changes in pedagogy point to the need for a higher level of video production value in most classroom video, replacing the default video protocol of an unattended camera in the back of the classroom. The rich and complex environment of today's classroom can be captured more fully using the higher level, but still easily manageable,…

The Correlation between Eating Utensils and Place of Sales in the Contamination of Escherichia coli in Food Sold at Campus Food Stalls

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Dewi Susanna

2015-04-01

Full Text Available Up to now, in general, the safety of food that is sold at any canteens in the campuses, the eating utensils are handled and the food stalls are managed are still uncertain. This research was aimed to understand the correlation between the eating utensils handling and the contamination of Escherichia coli (E. coli in the food sold by the food vendors in the campus. The cross-sectional design research applied on the food stalls in the university campus in Depok with a total number of 173 consumers as respondents. The variables observed as independent variables were the sanitation of the eating utensils and the sanitation of the dining place. The examination method of the Most Probable Number (MPN for E. coli was conducted to assess the food’s hygiene. The data analyzed using the chi-square test and followed by the logistic regression. The result showed that more than half of the food samples (59.54% were contaminated by E. coli. The storage place of the eating utensils was most significantly correlated with the E. coli contamination of the served food with an OR=0.45 (0.21-0.87. Therefore, it is necessary to promote the awareness of this risk and reinforce supervision by the Health Authorities and by the management of the place of sales to provide guidance to the food vendors and to the consumers as well. Further research is recommended to observe the E. coli contamination through clean water, eating utensils, the hands of the consumers and the napkins used to wipe dry the eating utensils.

Teachers’ intended classroom management strategies for students with ADHD: a cross-cultural study between South Korea and Germany

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Yumi Lee

2016-06-01

Full Text Available Background The purpose of this study was to investigate Korean and German teachers’ intentions of using classroom management strategies (CMS for students with attention-deficit/hyperactivity disorder (ADHD based on the theory of reasoned action (TRA and the theory of planned behavior (TPB. Participants and procedure Participants were 639 Korean and 317 German teachers. Disproportional stratified sampling was used. As a result, 264 Korean and 264 German matched teachers were obtained. Kos’s questionnaire was slightly modified. The survey instrument was distributed from September 2012 to December 2013. SPSS 22.0 was used to analyze the data. Results Korean teachers were more influenced by norms of colleagues and parents than German teachers were. Teachers in both countries have more favorable attitudes towards positive-oriented CMS compared to negative-oriented CMS, and perceived themselves as being able to control all CMS in the classroom. The TRA proved to better predict both Korean and German teachers’ intentions of using CMS compared to the TPB. Conclusions This study is an important step towards understanding teachers’ CMS in the cultural context of Korea and Germany. The findings of this study will be an essential resource to develop an ADHD management manual based on theoretical and cultural perspectives, so that teachers in both countries are prepared for students with ADHD in their classroom, rather than give up on them.

Association between stall surface and some animal welfare measurements in freestall dairy herds using recycled manure solids for bedding.

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Husfeldt, A W; Endres, M I

2012-10-01

The objective of this cross-sectional study was to investigate the association between stall surface and some animal welfare measurements in upper Midwest US dairy operations using recycled manure solids as bedding material. The study included 34 dairy operations with herd sizes ranging from 130 to 3,700 lactating cows. Forty-five percent of the herds had mattresses and 55% had deep-bedded stalls. Farms were visited once between July and October 2009. At the time of visit, at least 50% of the cows in each lactating pen were scored for locomotion, hygiene, and hock lesions. On-farm herd records were collected for the entire year and used to investigate mortality, culling, milk production, and mastitis incidence. Stall surface was associated with lameness and hock lesion prevalence. Lameness prevalence (locomotion score ≥ 3 on a 1 to 5 scale) was lower in deep-bedded freestalls (14.4%) than freestalls with mattresses (19.8%). Severe lameness prevalence (locomotion score ≥ 4) was also lower for cows housed in deep-bedded freestalls (3.6%) than for cows housed in freestalls with mattresses (5.9%). In addition, the prevalence of hock lesions (hock lesion scores ≥ 2 on a 1 to 3 scale, with 1=no lesion, 2=hair loss or mild lesion, and 3=swelling or severe lesion) and severe hock lesions (hock lesion score=3) was lower in herds with deep-bedded freestalls (49.4%; 6.4%) than in herds with mattresses (67.3%; 13.2%). Herd turnover rates were not associated with stall surface; however, the percentage of removals due to voluntary (low milk production, disposition, and dairy) and involuntary (death, illness, injury, and reproductive) reasons was different between deep-bedded and mattress-based freestalls. Voluntary removals averaged 16% of all herd removals in deep-bedded herds, whereas in mattress herds, these removals were 8%. Other welfare measurements such as cow hygiene, mortality rate, mastitis incidence, and milk production were not associated with stall surface

Experimental study of dynamic stall on Darrieus wind turbine blades

Science.gov (United States)

Brochier, G.; Fraunie, P.; Beguier, C.; Paraschivoiu, I.

1985-12-01

An experimental study of periodic vortex phenomena was performed on a model of a two straight-bladed Darrieus wind turbine under controlled-rotation conditions in the IMST water tunnel. The main focus of interest was the tip-speed ratios at which dynamic stall appears. Observations of this phenomenon from dye emission and the formation of hydrogen bubbles were made in the form of photographs, film and video recordings. Velocity measurements were obtained using the Laser-Doppler Velocimeter and components of velocity fluctuations could be determined quantitatively.

The Relationships between Selection and Processing Food with Escherichia coli Contaminant on Food Stall Serving

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Tris Eryando

2014-04-01

Full Text Available Escherichia coli in food stalls surrounding the X Campuss in Depok, year 2012. The research conducted to examine food safety, which were served in surrounding the campus X in Depok. Escherichia coli (E. coli existence was used to indicate the quality of hygiene and sanitation of the food that was served. Using the cross sectional method, the research examined the persons who served the food to be sold in the food stalls in the campus. There were 173 food servers chosen as the respondents from 10 different food stalls around the university. The existence of E. coli examined in the microbiology laboratory in the Faculty of Public Health. Using the most probable number (MPN method found that 59.54% of the food served in the campus were contaminated E. coli. Factors affecting the existence of E. coli were the raw materials (vegetables treated and the length of cooking of the materials (rice/beens. The improper treatment such as washing with no running water or even unwashed vegetables had 5 times risk of the E. coli contamination. Cooking less than 15 minutes was also more risky than cooking more than 15 minutes. As a result, this is very important to find a method to improve knowledge and to increase practical skills in food safety. Furthermore, in this research area may give contribution to avoid E. coli contamination which will prevent unnecessary illness among students in the campus.

Real-time continuous glucose monitoring systems in the classroom/school environment.

Science.gov (United States)

Benassi, Kari; Drobny, Jessica; Aye, Tandy

2013-05-01

Children with type 1 diabetes (T1D) spend 4-7 h/day in school with very little supervision of their diabetes management. Therefore, families have become more dependent on technology, such as use of real-time continuous glucose monitoring (RT-CGM), to provide increased supervision of their diabetes management. We sought to assess the impact of RT-CGM use in the classroom/school environment. Children with T1D using RT-CGM, their parents, and teachers completed a questionnaire about RT-CGM in the classroom/school environment. The RT-CGM was tolerated well in the classroom/school environment. Seventy percent of parents, 75% of students, and 51% of teachers found RT-CGM useful in the classroom/school environment. The students found the device to be more disruptive than did their parents and teachers. However, all three groups agreed that RT-CGM increased their comfort with diabetes management at school. Our study suggests that RT-CGM is useful and not disruptive in the classroom/school environment. The development of education materials for teachers could further increase its acceptance in the classroom/school environment.

Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

KAUST Repository

Viterbo, David; Michoud, Gregoire; Mosbach, Valentine; Dujon, Bernard; Richard, Guy-Franck

2016-01-01

Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.

Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

KAUST Repository

Viterbo, David

2016-03-16

Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.

Direct numerical simulation of a NACA0012 in full stall

International Nuclear Information System (INIS)

Rodríguez, I.; Lehmkuhl, O.; Borrell, R.; Oliva, A.

2013-01-01

Highlights: • Coherent structures at transitional and supercritical wake modes are presented. • Vortex shedding is detected in both wake modes. • KH instabilities and vortex shedding frequencies are identified. • Low-frequency flapping of the shear-layer is also detected after stall. • Local pressure distribution at both AOA is coherent with experimental observations. -- Abstract: This work aims at investigating the mechanisms of separation and the transition to turbulence in the separated shear-layer of aerodynamic profiles, while at the same time to gain insight into coherent structures formed in the separated zone at low-to-moderate Reynolds numbers. To do this, direct numerical simulations of the flow past a NACA0012 airfoil at Reynolds numbers Re = 50,000 (based on the free-stream velocity and the airfoil chord) and angles of attack AOA = 9.25° and AOA = 12° have been carried out. At low-to-moderate Reynolds numbers, NACA0012 exhibits a combination of leading-edge/trailing-edge stall which causes the massive separation of the flow on the suction side of the airfoil. The initially laminar shear layer undergoes transition to turbulence and vortices formed are shed forming a von Kármán like vortex street in the airfoil wake. The main characteristics of this flow together with its main features, including power spectra of a set of selected monitoring probes at different positions on the suction side and in the wake of the airfoil are provided and discussed in detail

Associations of Newly Qualified Teachers' Beliefs with Classroom Management Practices and Approaches to Instruction over One School Year

Science.gov (United States)

Aus, Kati; Jõgi, Anna-Liisa; Poom-Valickis, Katrin; Eisenschmidt, Eve; Kikas, Eve

2017-01-01

We focus on assessing whether newly qualified teachers' professional outcome expectations and their beliefs about students' intellectual potential are associated with teachers' self-reported classroom management and instructional practices. One hundred and eighteen novice teachers participating in the induction year programme were studied during…

Avaliação de diferentes materiais para recobrimento de camas em baias de galpão modelo free-stall

OpenAIRE

Cecchin, Daiane; Campos, Alessandro T.; Pires, Maria de F. A.; Lima, Renato R. de; Yanagi Junior, Tadayuki; Souza, Myriam C. M.

2014-01-01

Objetivou-se, com o presente trabalho, comparar o uso de cama de colchão de borracha e de areia no recobrimento da superfície de baias para confinamento tipo free-stall. Foram monitoradas 18 vacas holandesas confinadas em galpão modelo free-stall cujas baias foram recobertas com camas de areia e colchão de borracha (tratamentos). O delineamento experimental foi em blocos casualizados. Os parâmetros comportamentais estudados foram os tempos despendidos nas atividades: deitada em ócio e deitada...

Exploratory study of the effects of wing-leading-edge modifications on the stall/spin behavior of a light general aviation airplane

Science.gov (United States)

1979-01-01

Configurations with full-span and segmented leading-edge flaps and full-span and segmented leading-edge droop were tested. Studies were conducted with wind-tunnel models, with an outdoor radio-controlled model, and with a full-scale airplane. Results show that wing-leading-edge modifications can produce large effects on stall/spin characteristics, particularly on spin resistance. One outboard wing-leading-edge modification tested significantly improved lateral stability at stall, spin resistance, and developed spin characteristics.

Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics

Science.gov (United States)

Ericsson, L. E.; Reding, J. P.

1988-01-01

Analytical extrapolations are made from experimental subscale dynamics to predict full scale characteristics of dynamic stall. The method proceeds by establishing analytic relationships between dynamic and static aerodynamic characteristics induced by viscous flow effects. The method is then validated by predicting dynamic test results on the basis of corresponding static test data obtained at the same subscale flow conditions, and the effect of Reynolds number on the static aerodynamic characteristics are determined from subscale to full scale flow conditions.

Prediction of H.A.W.T. blade stall and performance

Energy Technology Data Exchange (ETDEWEB)

Giannakidis, G.; Graham, J.M.R. [Imperial College, Dept. of Aeronautics, London (United Kingdom)

1996-09-01

A model is being developed for the prediction of Horizontal Axis Wind Turbine blade stall and performance coupled with a simple aeroelastic analysis model. For the aerodynamic calculation a two dimensional unsteady Navier-Stokes solver on a sectional basis on the blade is coupled with a three dimensional vortex lattice wake. Pressure coefficient distributions are calculated from the two dimensional viscous flow in each blade section. The aerodynamic computations are coupled with a vibrating beam model in order to incorporate flapwise deformations of the blade. (au) 17 refs.

Stall margin improvement of an axial flow fan with end wall injection and suction; Hekimen fukidashi suidashi ni yoru han'yo jikuryu sofuki no shissoku kaizen

Energy Technology Data Exchange (ETDEWEB)

Nishioka, K.; Kuroda, H.; Obata, S.; Chimura, O. [National Defense Academy, Kanagawa (Japan)

1999-06-25

The experimental studies are conducted to reveal the mechanism of stall margin improvement of an axial flow fan by injection or suction from the end wall. In case of injection, the largest improvement is obtained by the injection at about 0. 14 {approx} 0 .21 times axial chord length downstream from leading edge. The reason for large improvement is that stall vortex, shed intermittent separation vortex and tip leakage vortex are dissipated by this injection, and also that this blowing suppresses the separation of boundary layer. In case of suction, the largest improvement is found for the suction from the end wall near leading edge. The amplitude of periodic static pressure after stall inception becomes smaller in comparison with injection cases. These effects are increased with the increase of suction flow rate, because the discharge of the vortex occurs more easily. On the other hand, the suction from the upstream of leading edge reduces the axial velocity near rotor tip, and then it induces stall. Also we tried to visualize the tip region flow, The suppression mechanism is discussed based on the visualization. The suppression of stall is successfully photographed. (author)

The Effects of Classroom Interventions on Off-Task and Disruptive Classroom Behavior in Children with Symptoms of Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review.

Directory of Open Access Journals (Sweden)

Geraldina F Gaastra

Full Text Available Children with attention-deficit/hyperactivity disorder (ADHD often exhibit problem behavior in class, which teachers often struggle to manage due to a lack of knowledge and skills to use classroom management strategies. The aim of this meta-analytic review was to determine the effectiveness of several types of classroom interventions (antecedent-based, consequence-based, self-regulation, combined that can be applied by teachers in order to decrease off-task and disruptive classroom behavior in children with symptoms of ADHD. A second aim was to identify potential moderators (classroom setting, type of measure, students' age, gender, intelligence, and medication use. Finally, it was qualitatively explored whether the identified classroom interventions also directly or indirectly affected behavioral and academic outcomes of classmates. Separate meta-analyses were performed on standardized mean differences (SMDs for 24 within-subjects design (WSD and 76 single-subject design (SSD studies. Results showed that classroom interventions reduce off-task and disruptive classroom behavior in children with symptoms of ADHD (WSDs: MSMD = 0.92; SSDs: MSMD = 3.08, with largest effects for consequence-based (WSDs: MSMD = 1.82 and self-regulation interventions (SSDs: MSMD = 3.61. Larger effects were obtained in general education classrooms than in other classroom settings. No reliable conclusions could be formulated about moderating effects of type of measure and students' age, gender, intelligence, and medication use, mainly because of power problems. Finally, classroom interventions appeared to also benefit classmates' behavioral and academic outcomes.

Visualization and image analysis of dynamic stall phenomenon for a Darrieus wind turbine; Darrieus fusha ni okeru doteki shissoku gensho no kashika to gazo kaisekini kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, N.; Shibuya, S.; Takano, T. [Niigata University, Niigata (Japan)

1999-10-25

The flow field around a Darrieus wind turbine is studied by flow visualization and PIV measurement in a rotating frame of reference to understand the unsteady nature of dynamic stall appearing at low tip-speed ratios. The qualitative nature of the dynamic stall observed by the flow visualization using dye injection technique is quantitatively reproduced in the instantaneous velocity distributions around the blade measured by PIV technique. These results indicate that two pairs of stall vortices are generated in one cycle of the turbine rotation and they grow in size as the tip-speed ratio decreases. The mechanism of the dynamic stall is found to be due to the flow separation over the suction side of the blade followed by the generation of in-flow motion from the pressure side to the suction side of the blade through the trailing edge. (author)

Behavior Modification in the Classroom

Science.gov (United States)

Whitman, Mryon; Whitman, Joan

1971-01-01

This article presents the theoretical rationale for behavior modification, principally through its comparison with traditional psychotherapies, and suggests some behavior modification techniques for the classroom management of maladaptive behavior. (Author)

More explicit communication after classroom-based crew resource management training: results of a pragmatic trial.

Science.gov (United States)

Verbeek-van Noord, Inge; de Bruijne, Martine C; Twisk, Jos W R; van Dyck, Cathy; Wagner, Cordula

2015-02-01

Aviation-based crew resource management trainings to optimize non-technical skills among professionals are often suggested for health care as a way to increase patient safety. Our aim was to evaluate the effect of a 2-day classroom-based crew resource management (CRM) training at emergency departments (EDs) on explicit professional oral communication (EPOC; non-technical skills). A pragmatic controlled before-after trial was conducted. Four EDs of general teaching hospitals were recruited (two intervention and two control departments). ED nurses and ED doctors were observed on their non-technical skills by means of a validated observation tool (EPOC). Our main outcome measure was the amount of EPOC observed per interaction in 30 minutes direct observations. Three outcome measures from EPOC were analysed: human interaction, anticipation on environment and an overall EPOC score. Linear and logistic mixed model analyses were performed. Models were corrected for the outcome measurement at baseline, days between training and observation, patient safety culture and error management culture at baseline. A statistically significant increase after the training was found on human interaction (β=0.27, 95% CI 0.08-0.49) and the overall EPOC score (β=0.25, 95% CI 0.06-0.43), but not for anticipation on environment (OR=1.19, 95% CI .45-3.15). This means that approximately 25% more explicit communication was shown after CRM training. We found an increase in the use of CRM skills after classroom-based crew resource management training. This study adds to the body of evidence that CRM trainings have the potential to increase patient safety by reducing communication flaws, which play an important role in health care-related adverse events. © 2014 John Wiley & Sons, Ltd.

Exploring the effects of a universal classroom management training programme on teacher and child behaviour: A group randomised controlled trial and cost analysis

OpenAIRE

O'Neill, Donal

2017-01-01

Teachers frequently struggle to cope with conduct problems in the classroom. The aim of this study was to assess the effectiveness of the Incredible Years Teacher Classroom Management Training Programme for improving teacher competencies and child adjustment. The study involved a group randomised controlled trial which included 22 teachers and 217 children (102 boys and 115 girls). The average age of children included in the study was 5.3 years (standard deviation = 0.89). Teacher...

Discipline and Rules in Four Hong Kong Kindergarten Classrooms: A Qualitative Case Study

Science.gov (United States)

Ho, Joyce; Grieshaber, Susan Jane; Walsh, Kerryann

2017-01-01

Classroom discipline is a topic of international interest and teachers are bombarded with advice regarding how to and why they should manage children's behaviour in their classrooms. This paper draws on data related to classroom discipline gathered from a detailed classroom observation schedule, teacher interviews, and field notes with four…

Mobile Health Based System for Managing and Maintaining Health Data in Classroom: Case Study

Directory of Open Access Journals (Sweden)

Dalibor Serafimovski

2017-05-01

Full Text Available It is necessary for young people to get appropriate medical education so that they can learn how to properly take care of their health from an early age. In this paper we are presenting a study that enables practical implementation of a mobile system for monitoring students’ health using mobile devices and managing medical data in the classroom. About 600 students were engaged for the purpose of this study. The study results suggest that the application of these technologies leads to an increased concern about students’ health and their proper medical education.

A Meta-Analysis: Student Misbehaviors That Affect Classroom Management

Directory of Open Access Journals (Sweden)

Gülay Dalgıç

2014-05-01

Full Text Available Research on student misbehaviors in classroom have focused on the identification of most frequent misbehaviors and individual practices used by the teachers. However there is still a significant gap about the demographic and other factors that affect teachers’ perceptions of misbehaviors in classrooms. This meta-analysis reviewed the literature in Turkey on student misbehaviors from the views of teachers and demographic factors in theses and published articles between 2000-2012. The sample included 3648 teachers gathered from 16 studies. The results highlight that task avoidance, constant talking with classmates, verbal hostility towards peers and teacher, indifference to study subject during classes, damaging school stuff, and coming late are the most frequent student misbehavior types reported by teachers. Results showed a small relation between perceived student misbehavior and teachers’ teaching field, teacher seniority, educational background of teachers, and number of students in classroom. Gender was not determined as a statistically significant variable in determining teachers’ perceptions of student misbehavior. Practical implications for future research and practices are discussed.

RANS study of unsteady flow around a profile blade : application to stall of horizontal axis wind turbine

Energy Technology Data Exchange (ETDEWEB)

Belkheir, N. [Khemis Miliana Univ., Ain Defla (Algeria); Dizene, R. [Univ. des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Laboratoire de Mecanique Avancee; Khelladi, S.; Massouh, F.; Dobrev, I. [Arts et Metiers Paris Tech., Paris (France)

2010-07-01

The shape of an airfoil is designed to achieve the best aerodynamic performance. An aerofoil section undergoes dynamic stall when subjected to any form of unsteady angle of pitch. The study of a horizontal-axis wind turbine (HAWT) under wind operating conditions is complex because it is subject to instantaneous speed and wind direction variation. When turbine blades are driven into a dynamic stall, the lift coefficient drops suddenly resulting in a degradation in aerodynamic performance. This study presented steady and unsteady wind load predictions over an oscillating S809 airfoil tested in a subsonic wind tunnel. A model of sinusoidal pitch oscillations was used. The values for the angles of attack in steady state ranged from -20 to +40 degrees. The model considered 3 frequencies and 2 amplitudes. The two-dimensional numerical model simulated the instantaneous change of wind direction with respect to the turbine blade. Results were compared with data measurements of S809 aerofoil. Reasonable deviations were obtained between the predicted and experimental results for pitch oscillations. The URANS approach was used to predict the stall while the software FLUENT was used for the numerical solution. It was concluded that the behaviour of the unsteady flow in the wind farm must be considered in order to obtain an accurate estimate of the wind turbine aerodynamic load. 12 refs., 5 figs.

Numerical study on a single bladed vertical axis wind turbine under dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Bangga, Galih [Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, Stuttgart (Germany); Hutomo, Go; Sasongko, Herman [Dept. of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya (Indonesia); Wiranegara, Raditya [School of Mechanical Aerospace and Civil Engineering, University of Manchester, Manchester (United Kingdom)

2017-01-15

The aim of this study is to investigate the flow development of a single bladed vertical axis wind turbine using Computational fluid dynamics (CFD) methods. The blade is constructed using the NACA 0012 profile and is operating under stalled conditions at tip speed ratio of 2. Two dimensional simulations are performed using a commercial CFD package, ANSYS Fluent 15.0, employing the Menter-SST turbulence model. For the preliminary study, simulations of the NACA 0012 airfoil under static conditions are carried out and compared with available measurement data and calculations using the boundary layer code XFOIL. The CFD results under the dynamic case are presented and the resulting aerodynamic forces are evaluated. The turbine is observed to generate negative power at certain azimuth angles which can be divided into three main zones. The blade vortex interaction is observed to strongly influence the flow behavior near the blade and contributes to the power production loss. However, the impact is considered small since it covers only 6.4 % of the azimuth angle range where the power is negative compared to the dynamic stall impact which covers almost 22 % of the azimuth angle range.

Blade tip, finite aspect ratio, and dynamic stall effects on the Darrieus rotor

Science.gov (United States)

Paraschivoiu, I.; Desy, P.; Masson, C.

1988-02-01

The objective of the work described in this paper was to apply the Boeing-Vertol dynamic stall model in an asymmetric manner to account for the asymmetry of the flow between the left and right sides of the rotor. This phenomenon has been observed by the flow visualization of a two-straight-bladed Darrieus rotor in the IMST water tunnel. Also introduced into the aerodynamic model are the effects of the blade tip and finite aspect ratio on the aerodynamic performance of the Darrieus wind turbine. These improvements are compatible with the double-multiple-streamtube model and have been included in the CARDAAV computer code for predicting the aerodynamic performance. Very good agreement has been observed between the test data (Sandia 17 m) and theoretical predictions; a significant improvement over the previous dynamic stall model was obtained for the rotor power at low tip speed ratios, while the inclusion of the finite aspect ratio effects enhances the prediction of the rotor power for high tip speed ratios. The tip losses and finite aspect ratio effects were also calculated for a small-scale vertical-axis wind turbine, with a two-straight-bladed (NACA 0015) rotor.

Grid support of a wind farm with active stall wind turbines and AC grid connection

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Sørensen, Poul Ejnar; Iov, F.

2006-01-01

grid connection. The designed control system has the task of enabling such a wind farm to provide the best grid support. It is based on two control levels: a supervisory control level, which controls the power production of the whole farm by sending out reference signals to each individual wind turbine......One of the main concerns in the grid integration of large wind farms is their ability to behave as active controllable components in the power system. This article presents the design of a new integrated power control system for a wind farm made up exclusively of active stall wind turbines with AC......, and a local control level, which ensures that the reference power signals at the wind turbine level are reached. The ability of active stall wind farms with AC grid connection to control the power production to the reference power ordered by the operators is assessed and discussed by means of simulations....

Why Do Some Teachers Change and Others Don't? A Review of Studies about Factors Influencing In-Service and Pre-Service Teachers' Change in Classroom Management

Science.gov (United States)

Girardet, Céline

2018-01-01

Considering the crucial goals dependent on classroom management, such as creating a classroom environment conducive to student learning and facilitating student engagement and motivation, it is an important skill for teachers to learn. Accordingly, this literature review aims at untangling the factors influencing the evolution of teachers'…

Effects of Classroom Management Profiles of Pre-School Teachers on Social Skills and Problem Behaviors of Children

OpenAIRE

METİN, Şermin; AYDOĞAN, Yasemin; KAVAK, Şule; MERCAN, Zerrin

2018-01-01

Thisresearch was conducted to determine the classroom management profile ofpreschool teachers and to examine the influence of teachers' classroommanagement profiles on children's social skills and problem behaviors. Theresearch was carried out in 2015-2016 educational year with teachers workinginkindergartens affiliated to Provincial Directorate of National Education inGaziantep province center and children in their classes. The study groupconsists of 485 children and 45 teachers wh...

Dynamic stall study of a multi-element airfoil

Science.gov (United States)

Tung, Chee; Mcalister, Kenneth W.; Wang, Clin M.

1992-01-01

Unsteady flow behavior and load characteristics of a VR-7 airfoil with and without a slat were studied in the water tunnel of the Aeroflightdynamics Directorate, NASA Ames Research Center. Both airfoils were oscillated sinusoidally between 5 and 25 degrees at a Reynolds number of 200,000 to obtain the unsteady lift, drag and pitching moment data. A fluorescing dye was released from an orifice located at the leading edge of the airfoil for the purpose of visualizing the boundary layer and wake flow. The flow field and load predictions of an incompressible Navier-Stokes code based on a velocity-vorticity formulation were compared with the test data. The test and predictions both confirm that the slatted VR-7 airfoil delays both static and dynamic stall as compared to the VR-7 airfoil alone.

Proposed Chevron Tengiz venture stalls amid Soviet political squabble

International Nuclear Information System (INIS)

Anon.

1991-01-01

This paper reports on the status of foreign investment in Soviet oil and gas joint ventures which has reached a critical juncture. Just as the U.S. is considering granting most favored nation trade status to the U.S.S.R., the joint venture petroleum deal seen as the litmus test for such deals-Chevron Corp.'s proposed addition of supergiant Tengiz oil field to its Caspian Sea joint venture-has stalled amid controversy. Unconfirmed reports from Soviet officials and other foreign joint venture participants in the U.S.S.R. have Chevron pulling out of the long negotiated, multibillion dollar project after the Soviets rejected the company's terms. Chevron, however, insists the project is still alive

The Role of Knowledge and Skills for Managing Emotions in Adaptation to School: Social Behavior and Misconduct in the Classroom

Science.gov (United States)

Lopes, Paulo N.; Mestre, Jose M.; Guil, Rocio; Kremenitzer, Janet Pickard; Salovey, Peter

2012-01-01

Students' ability to evaluate emotionally challenging situations and identify effective strategies for managing emotions in themselves and others was negatively related to poor classroom social behavior across three studies. These studies, involving 463 students from two Spanish high schools and one American university, examined indicators of…

Pre-Service Students' Perceptions and Experiences of Digital Storytelling in Diverse Classrooms

Science.gov (United States)

Condy, Janet; Chigona, Agnes; Gachago, Daniela; Ivala, Eunice; Chigona, Agnes

2012-01-01

The purpose of this paper is to analyse an innovative teaching and learning practice in which pre-service student teachers at the CPUT used digital stories to reflect on their experiences of diversity in their classroom. Managing diverse classrooms is one of the main challenges for all teachers. Digital storytelling can help manage such…

The Classroom Animal: Snails.

Science.gov (United States)

Kramer, David S.

1985-01-01

Points out that snails are interesting and easily-managed classroom animals. One advantage of this animal is that it requires no special attention over weekends or holidays. Background information, anatomy, reproduction, and feeding are discussed, along with suggestions for housing aquatic and/or land snails. (DH)

Early Professional Development in the Scottish Context: Pre-Service High School Teachers and the Management of Behaviour in Classrooms

Science.gov (United States)

Hamilton, Lorna

2015-01-01

This paper gives an account of an exploratory piece of research focused on understanding more fully the nature of pre-service teachers' developing approaches to classroom behaviour management on a one-year postgraduate teacher education programme in the Scottish context. Drawing on individual and focus group interviews as well as journaling of…

Classroom planning and organizing as tasks for the home economics teacher at secondary schools / Lesley Ann Greyvenstein

OpenAIRE

Greyvenstein, Lesley Ann

1986-01-01

Classroom management, as part-discipline of Educational Management, is a function of the teacher in his role of teacher-manager, consisting of the specific regulative tasks or actions performed by the teacher to facilitate the achievement of effective education within the classroom. The four major classroom managerial tasks for the teacher are the planning, organizing, leading and controlling actions, each consisting of numerous sub-tasks, which, although researched as separ...

Strategies for Teachers to Manage Stuttering in the Classroom: A Call for Research.

Science.gov (United States)

Davidow, Jason H; Zaroogian, Lisa; Garcia-Barrera, Mauricio A

2016-10-01

This clinical focus article highlights the need for future research involving ways to assist children who stutter in the classroom. The 4 most commonly recommended strategies for teachers were found via searches of electronic databases and personal libraries of the authors. The peer-reviewed evidence for each recommendation was subsequently located and detailed. There are varying amounts of evidence for the 4 recommended teacher strategies outside of the classroom, but there are no data for 2 of the strategies, and minimal data for the others, in a classroom setting. That is, there is virtually no evidence regarding whether or not the actions put forth influence, for example, stuttering frequency, stuttering severity, participation, or the social, emotional, and cognitive components of stuttering in the classroom. There is a need for researchers and speech-language pathologists in the schools to study the outcomes of teacher strategies in the classroom for children who stutter.

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

International Nuclear Information System (INIS)

Mendoza, Victor; Goude, Anders; Bachant, Peter; Wosnik, Martin

2016-01-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion. (paper)

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

Science.gov (United States)

Mendoza, Victor; Bachant, Peter; Wosnik, Martin; Goude, Anders

2016-09-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

A comparison of two methods of teaching. Computer managed instruction and keypad questions versus traditional classroom lecture.

Science.gov (United States)

Halloran, L

1995-01-01

Computers increasingly are being integrated into nursing education. One method of integration is through computer managed instruction (CMI). Recently, technology has become available that allows the integration of keypad questions into CMI. This brings a new type of interactivity between students and teachers into the classroom. The purpose of this study was to evaluate differences in achievement between a control group taught by traditional classroom lecture (TCL) and an experimental group taught using CMI and keypad questions. Both control and experimental groups consisted of convenience samples of junior nursing students in a baccalaureate program taking a medical/surgical nursing course. Achievement was measured by three instructor-developed multiple choice examinations. Findings demonstrated that although the experimental group demonstrated increasingly higher test scores as the semester progressed, no statistical difference was found in achievement between the two groups. One reason for this may be phenomenon of vampire video. Initially, the method of presentation overshadowed the content. As students became desensitized to the method, they were able to focus and absorb more content. This study suggests that CMI and keypads are a viable teaching option for nursing education. It is equal to TCL in student achievement and provides a new level of interaction in the classroom setting.

A Tale from Three Countries: The Classroom Management Practices of Pre-Service Teachers from Australia, Canada and the United Kingdom

Science.gov (United States)

Woodcock, Stuart; Reupert, Andrea

2017-01-01

The purpose of this research was to (i) identify Australian, Canadian and United Kingdom (UK) pre-service teachers' use, confidence and success of various classroom management strategies and (ii) to ascertain any significant differences between the three cohorts. Significant differences were found amongst the cohort with the UK pre-service…

Optimal parameters for the FFA-Beddoes dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A; Mert, M [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden); Madsen, H A [Risoe National Lab., Roskilde (Denmark)

1999-03-01

Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for wind turbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empiricial parameters. In this paper a study of finding appropriate parameters to use with the Beddoes-Leishman model is discussed. Minimisation of the `tracking error` between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters. The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations, give rise to quite different predictions of aerodynamic damping which is discussed. (au)

PROFICIENT CLASSROOM MANAGEMENT THROUGH FOCUSED MATHEMATIC TEACHING

Directory of Open Access Journals (Sweden)

Marcus Samuelsson

2017-12-01

Full Text Available A not entirely unusual position among teachers is that they believe that they must first establish a peaceful classroom before they can begin to teach the subject. This research, shows how a proficient mathematics teacher teaches his subject and thereby creates a quiet and focused classroom and exerts effective leadership, just by teaching mathematics. The researchers observed a male mathematics teacher for almost half a year, i.e. one semester. The results of research present several patterns that the researchers saw during the observations of his teaching. The teacher showed an interest in each student’s mathematical thinking and expressed explicitly how students were expected to learn mathematics. He also directed students’ attention to mathematics and established a culture where all solutions were important in the teaching process. In the teaching process, he used multiple representations to motivate students and a lot of supportive expressions that made them feel that they were able to learn mathematics. He worked patiently to establish structures, and there was almost no disruptive behaviour. Students simply did not have time to interfere because they were so engaged in learning mathematics.

Phosphorylated RPA recruits PALB2 to stalled DNA replication forks to facilitate fork recovery.

Science.gov (United States)

Murphy, Anar K; Fitzgerald, Michael; Ro, Teresa; Kim, Jee Hyun; Rabinowitsch, Ariana I; Chowdhury, Dipanjan; Schildkraut, Carl L; Borowiec, James A

2014-08-18

Phosphorylation of replication protein A (RPA) by Cdk2 and the checkpoint kinase ATR (ATM and Rad3 related) during replication fork stalling stabilizes the replisome, but how these modifications safeguard the fork is not understood. To address this question, we used single-molecule fiber analysis in cells expressing a phosphorylation-defective RPA2 subunit or lacking phosphatase activity toward RPA2. Deregulation of RPA phosphorylation reduced synthesis at forks both during replication stress and recovery from stress. The ability of phosphorylated RPA to stimulate fork recovery is mediated through the PALB2 tumor suppressor protein. RPA phosphorylation increased localization of PALB2 and BRCA2 to RPA-bound nuclear foci in cells experiencing replication stress. Phosphorylated RPA also stimulated recruitment of PALB2 to single-strand deoxyribonucleic acid (DNA) in a cell-free system. Expression of mutant RPA2 or loss of PALB2 expression led to significant DNA damage after replication stress, a defect accentuated by poly-ADP (adenosine diphosphate) ribose polymerase inhibitors. These data demonstrate that phosphorylated RPA recruits repair factors to stalled forks, thereby enhancing fork integrity during replication stress. © 2014 Murphy et al.

A Cross-Cultural Study of Teachers' Beliefs and Strategies on Classroom Behavior Management in Urban American and Korean School Systems

Science.gov (United States)

Shin, Sunwoo; Koh, Myung-Sook

2007-01-01

The purpose of this study is to investigate teachers' beliefs on classroom behavior management strategies for students in urban public high schools between teachers in the United States and the Republic of Korea. This study incorporates data collected from teacher self-reported survey questionnaire, which is the Attitudes and Beliefs on Classroom…

Power management in hydraulically actuated mobile equipment

DEFF Research Database (Denmark)

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

2008-01-01

The focus of the current paper is on the control of hydraulic systems when utilizing the advances that electronic control may bring with regard to power management, prioritized flow sharing and anti-stall, arising from being able to control both pump, valves and engine electronically. A simple mo...

Speech-Language Pathologists' and Teachers' Perceptions of Classroom-Based Interventions.

Science.gov (United States)

Beck, Ann R.; Dennis, Marcia

1997-01-01

Speech-language pathologists (N=21) and teachers (N=54) were surveyed regarding their perceptions of classroom-based interventions. The two groups agreed about the primary advantages and disadvantages of most interventions, the primary areas of difference being classroom management and ease of data collection. Other findings indicated few…

Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

Science.gov (United States)

Azizi, Mohammad Ali; Brouwer, Jacob

2017-10-01

A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

Psychological Problems and Challenge In EFL Speaking Classroom

Directory of Open Access Journals (Sweden)

Win Listyaningrum Arifin

2017-07-01

Full Text Available Psychological aspect regarding to learning attitudes plays in determining learning achievement. Psychological problems also involve not only to the students but also teacher. Less-confidence, speech anxiety, and low self-esteem are almost common problem in classroom, and occur on both teachers and students. Students who have low of self-confidence are often hardly able to control themselves for public speaking in the classroom, like, Governing his/ her behavior on that his/her peers think, lose belief on self, thinking that his/her friends dis-appraising, afraid of getting mistakes, etc. However, teachers which are low self-esteem and confidence also lose their performance and ability to manage their classroom optimally. Low self-esteem may caused by teacher’s poor understanding on subject matter. Both of psychological problems impact on dis-effectiveness of classroom activities. This paper takes accounts of some psychological problems of students and teachers in English speaking classroom, and some guidelines to overcome. At the last discus, this paper also provides some keys of how to make good classroom atmosphere.

Characterization of Mathematics Instructional Practises for Prospective Elementary Teachers with Varying Levels of Self-Efficacy in Classroom Management and Mathematics Teaching

Science.gov (United States)

Lee, Carrie W.; Walkowiak, Temple A.; Nietfeld, John L.

2017-01-01

The purpose of this study was to investigate the relationship between prospective teachers' (PTs) instructional practises and their efficacy beliefs in classroom management and mathematics teaching. A sequential, explanatory mixed-methods design was employed. Results from efficacy surveys, implemented with 54 PTs were linked to a sample of…

Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

NARCIS (Netherlands)

Kruyt, J.W.; Heijst, Van G.F.; Altshuler, D.L.; Lentink, David

2015-01-01

Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle

AN ANALYSIS OF CANDIDATE TEACHERS’ VIEWS ON THE EFFECT OF TECHNOLOGY USE IN EDUCATION OVER CLASSROOM MANAGEMENT

OpenAIRE

İLGAR, Lütfü

2018-01-01

Technology hasbeen developing rapidly in our age and it has influenced every aspect of our livesas well as education and teaching. In our country, the use of technology foreducation is considered to be the means of catching up with developed countriesby improving quality and a great deal of investment is made on this field.The purpose ofthis research is to determine the perspectives of candidate teachers towardshow educational technology affects classroom management, what its advantagesand di...

Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Dai, J.C. [College of Mechanical and Electrical Engineering, Central South University, Changsha (China); School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Hu, Y.P.; Liu, D.S. [School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Long, X. [Hara XEMC Windpower Co., Ltd., Xiangtan (China)

2011-03-15

The aerodynamic loads for MW scale horizontal-axis wind turbines are calculated and analyzed in the established coordinate systems which are used to describe the wind turbine. In this paper, the blade element momentum (BEM) theory is employed and some corrections, such as Prandtl and Buhl models, are carried out. Based on the B-L semi-empirical dynamic stall (DS) model, a new modified DS model for NACA63-4xx airfoil is adopted. Then, by combing BEM modified theory with DS model, a set of calculation method of aerodynamic loads for large scale wind turbines is proposed, in which some influence factors such as wind shear, tower, tower and blade vibration are considered. The research results show that the presented dynamic stall model is good enough for engineering purpose; the aerodynamic loads are influenced by many factors such as tower shadow, wind shear, dynamic stall, tower and blade vibration, etc, with different degree; the single blade endures periodical changing loads but the variations of the rotor shaft power caused by the total aerodynamic torque in edgewise direction are very small. The presented study approach of aerodynamic loads calculation and analysis is of the university, and helpful for thorough research of loads reduction on large scale wind turbines. (author)

First grade classroom-level adversity: Associations with teaching practices, academic skills, and executive functioning.

Science.gov (United States)

Abry, Tashia; Granger, Kristen L; Bryce, Crystal I; Taylor, Michelle; Swanson, Jodi; Bradley, Robert H

2018-05-24

Using data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development and a model-building approach, the authors examined direct and indirect associations between first-grade (G1) classroom-level adversity (CLA), G1 teaching practices, and student (N = 1,073; M = 6.64 years; 49% girls; 82% White) academic skills and executive functioning in G1 and third grades (G3). Teachers reported the prevalence of adversity among their students (e.g., poor home/family life, poor academic/social readiness). Observers rated G1 teaching practices: teachers' classroom management, controlling instruction, and amount of academic instruction (classroom observation system). Children completed literacy and math assessments at 54 months, G1, and G3 (Woodcock Johnson Letter-Word Identification and Applied Problems), and executive functioning at G1 and G3 (Tower of Hanoi). Direct associations emerged between CLA and controlling instruction (positive), classroom management, and academic instruction (both negative). In addition, CLA was related to G1 literacy (but not math) directly and indirectly via classroom management (negatively) and controlling instruction (positively). The addition of G3 outcomes revealed a negative direct longitudinal association between CLA and G3 executive functioning, and indirect associations with G3 literacy and math through G1 teaching practices and literacy. Results support the notion that collective student characteristics influence student outcomes in part through teaching practices and suggest that teachers and students may benefit from the diffusion of high-adversity classroom compositions when possible. Moreover, in high-adversity classrooms teachers and students may benefit from supports targeting classroom management and foundational student competencies. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Analysis of Vaneless Diffuser Stall Instability in a Centrifugal Compressor

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Elias Sundström

2017-11-01

Full Text Available Numerical simulations based on the large eddy simulation approach were conducted with the aim to explore vaneless diffuser rotating stall instability in a centrifugal compressor. The effect of the impeller blade passage was included as an inlet boundary condition with sufficiently low flow angle relative to the tangent to provoke the instability and cause circulation in the diffuser core flow. Flow quantities, velocity and pressure, were extracted to accumulate statistics for calculating mean velocity and mean Reynolds stresses in the wall-to-wall direction. The paper focuses on the assessment of the complex response of the system to the velocity perturbations imposed, the resulting pressure gradient and flow curvature effects.

Primary School Environment Trend, Class-Ratio and Head Teachers Overcrowded Classrooms Management Strategies in Northern Senatorial District of Ondo State, Nigeria

Science.gov (United States)

Babatunde, Ehinola Gabriel

2015-01-01

Primary school Enrolment Trend, Class-Ratio and Head Teachers overcrowded classrooms management strategies in Northern Senatorial District of Ondo State, Nigeria was investigated. The purpose of the study is to examine the current enrolment trend in public primary schools in northern senatorial District of Ondo State. Also, is to ascertain the…

The Good Behavior Game: A Classroom-Behavior Intervention Effective across Cultures

Science.gov (United States)

Nolan, Julene D.; Houlihan, Daniel; Wanzek, Megan; Jenson, William R.

2014-01-01

Few classroom behavioral interventions have been thoroughly studied using culturally and linguistically diverse populations, international student populations, or those from diverse socio-economic backgrounds. Yet, having such tools for school psychologists and teachers is critical for behavior management in the classroom. One important exception…

Teacher classroom practices and Mathematics performance in ...

African Journals Online (AJOL)

Education and Skills Development, Human Sciences Research Council, Pretoria, South Africa ... Solving and Metacognitive Strategies, and Collaboration. ... Close monitoring, adequate pacing and classroom management, as well as clarity of ...

Efektivitas Flipped Classroom Terhadap Sikap Dan Ketrampilan Belajar Matematika Di Smk

OpenAIRE

Damayanti, Herry Novis; Sutama, Sutama

2016-01-01

The aim of the research is developed attitude resposiility, and skill learning of mathematic teaching based Flipped Classroom. The final result of the research is to taste effectiveness of mathematic teaching model based Flipped Classroom. The research method is research and development that includes introduction, field study of teaching management in the school, planning and preparing Flipped Classroom model, implementation of teaching first cycle, second cycle, and third cycle, and exam of ...

Drama and Composition in the Classroom

Science.gov (United States)

Urkowitz, Steven

1978-01-01

Reports on the success of a remedial English class that read and performed plays by Euripides, William Shakespeare, and Arthur Miller. Describes the practical details of the course's organization and classroom management that other teachers can adapt. (RL)

Classroom management of situated group learning: A research study of two teaching strategies

Science.gov (United States)

Smeh, Kathy; Fawns, Rod

2000-06-01

Although peer-based work is encouraged by theories in developmental psychology and although classroom interventions suggest it is effective, there are grounds for recognising that young pupils find collaborative learning hard to sustain. Discontinuities in collaborative skill during development have been suggested as one interpretation. Theory and research have neglected situational continuities that the teacher may provide in management of formal and informal collaborations. This experimental study, with the collaboration of the science faculty in one urban secondary college, investigated the effect of two role attribution strategies on communication in peer groups of different gender composition in three parallel Year 8 science classes. The group were set a problem that required them to design an experiment to compare the thermal insulating properties of two different materials. This presents the data collected and key findings, and reviews the findings from previous parallel studies that have employed the same research design in different school settings. The results confirm the effectiveness of social role attribution strategies in teacher management of communication in peer-based work.

An Investigation of Burn-Out Levels of Teachers Working in Elementary and Secondary Educational Institutions and Their Attitudes to Classroom Management

Science.gov (United States)

Yavuz, Mustafa

2009-01-01

In the present study, the burn-out levels of teachers working in elementary and secondary educational institutions and their attitudes and beliefs regarding classroom management are investigated with respect to gender, job seniority, class size and the types of schools they have been working in. This is a survey method research and quantitative…

Rethinking Classroom Observation

Science.gov (United States)

Grimm, Emily Dolci; Kaufman, Trent; Doty, Dave

2014-01-01

If your professional learning seems stalled, maybe you could put yourself and your colleagues in the driver's seat of professional development. The authors describe a professional learning approach that gives teachers both a say in what they focus their learning on and a chance to practice and refine teaching strategies that they hope to…

CLASSROOM OBSERVATION- A POWERFUL TOOL FOR CONTINUOUS PROFESSIONAL DEVELOPMENT (CPD

Directory of Open Access Journals (Sweden)

Shanjida Halim

2018-05-01

Full Text Available For making teaching and learning more visible, classroom observation plays a central role. It provides teachers with constructive critical feedback in order to improve their classroom management and instructional techniques. For teachers it is important to observe the interaction between teacher-learner within the classroom because it can determine the learning opportunities that students get. Not only that, classroom observation encourages colleagues to collaborate to improve teacher practice and student learning. Feedback from classroom observations is an effective way for providing teachers with the information they need about their classroom behavior, and it can help them in their continuous professional development (CPD. This paper is based upon a practical approach to professional development among teachers through classroom observation. Since we, as teachers, are not born with innate teaching abilities, in fact, we learn and develop gradually with the help of some practical approaches, and classroom observation is a well-known powerful practical approach in primary and higher education to help teachers improve their teaching quality. This article mainly highlights the importance of classroom observation and its guidelines adapted from Observing Classes-CETaL. Further, it emphasizes the limitations of classroom observation, and suggests the ways to carry it out effectively based upon Observing Classes CETaL Model.

Active flow control of the laminar separation bubble on a plunging airfoil near stall

Science.gov (United States)

Pande, Arth; Agate, Mark; Little, Jesse; Fasel, Hermann

2017-11-01

The effects of small amplitude (A/c = 0.048) high frequency (πfc/U∞ = 0.70) plunging motion on the X-56A airfoil are examined experimentally at Re = 200,000 for 12° angle of attack (CL,MAX = 12.25°) . The purpose of this research is to study the aerodynamic influence of structural motion when the wing is vibrating close to its eigenfrequency near static stall. Specific focus is placed on the laminar separation bubble (LSB) near the leading edge and its control via plasma actuation. In the baseline case, the leading edge bubble bursts during the oscillation cycle causing moment stall. A collaborative computational effort has shown that small amplitude forcing at a frequency that is most amplified by the primary instability of the LSB (FLSB+= 1, Fc+= 52) generates coherent spanwise vortices that entrain freestream momentum, thus reducing separation all while maintaining a laminar flow state. Results (PIV and surface pressure) indicate that a similar control mechanism is effective in the experiments. This is significant given the existence of freestream turbulence in the wind tunnel which has been shown to limit the efficacy of this active flow control technique in a model problem using Direct Numerical Simulation. The implications of these results are discussed.

Simulation model of a transient fault controller for an active-stall wind turbine

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Soerensen, P.; Bak Jensen, B.

2005-01-01

This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation in case of such faults. The design of the controller is described and its performance assessed by simulations. The control strategies are explained and the behaviour of the turbine discussed. (author)

Active unsteady aerodynamic suppression of rotating stall in an incompressible flow centrifugal compressor with vaned diffuser

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1991-01-01

A mathematical model is developed to analyze the suppression of rotating stall in an incompressible flow centrifugal compressor with a vaned diffuser, thereby addressing the important need for centrifugal compressor rotating stall and surge control. In this model, the precursor to to instability is a weak rotating potential velocity perturbation in the inlet flow field that eventually develops into a finite disturbance. To suppress the growth of this potential disturbance, a rotating control vortical velocity disturbance is introduced into the impeller inlet flow. The effectiveness of this control is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. To demonstrate instability control, this model is then used to predict the control effectiveness for centrifugal compressor geometries based on a low speed research centrifugal compressor. These results indicate that reductions of 10 to 15 percent in the mean inlet flow coefficient at instability are possible with control waveforms of half the magnitude of the total disturbance at the inlet.

A Beddoes-Leishman type dynamic stall model in state-space and indicial formulations[Wind turbines

Energy Technology Data Exchange (ETDEWEB)

Hansen, M.H.; Gaunaa, M.; Aagaard Madsen, H.

2004-06-01

This report contains a description of a Beddoes-Leishman type dynamic stall model in both a state-space and an indicial function formulation. The m odel predicts the unsteady aerodynamic foreces and moment on an airfoil section undergoing arbitrary motion in heavy, lead-lag, and pitch. The model includes the effects of shed vorticity from the trailing edge (Theodorsen Theory), and the effects of an instationary trailing edge separation point. The governing equations of the model are nonlinear, and they are linearized about a steady state for application in stability analyzes. A validation is carried out by comparing the response of the model with inviscid solutions and observing the general behavior of the model using known airfoil data as input. The proposed dyanmic model gives results identical to inviscid solutions within the attached-flow region; and it exhibits the expected dynamic features, such as overshoot of the lift, in the stall region. The linearized model is shown to give identical results to the full model for small amplitude oscillations. furthermore, it is shown that the response of finite thickness airfoils can be reproduced to a high accuracy by the use of specific inviscid response functions. (au)

Effects of a Tailored Incredible Years Teacher Classroom Management Programme on On-Task Behaviour of School Children with ADHD in Addis Ababa

Science.gov (United States)

Mohammed, Feruz

2018-01-01

Attention-Deficit/Hyperactivity Disorder (ADHD) is a persistent pattern of behaviours characterized by inattention, hyperactivity and impulsivity. This study evaluates the effects of a tailored Incredible Years Teacher Classroom Management (IYTCM) programme aimed to improve participating children's on-task behaviour in a group of 6 to 10 year old…

The interactive learning toolkit: technology and the classroom

Science.gov (United States)

Lukoff, Brian; Tucker, Laura

2011-04-01

Peer Instruction (PI) and Just-in-Time-Teaching (JiTT) have been shown to increase both students' conceptual understanding and problem-solving skills. However, the time investment for the instructor to prepare appropriate conceptual questions and manage student JiTT responses is one of the main implementation hurdles. To overcome this we have developed the Interactive Learning Toolkit (ILT), a course management system specifically designed to support PI and JiTT. We are working to integrate the ILT with a fully interactive classroom system where students can use their laptops and smartphones to respond to ConcepTests in class. The goal is to use technology to engage students in conceptual thinking both in and out of the classroom.

Classrooms.

Science.gov (United States)

Butin, Dan

This paper addresses classroom design trends and the key issues schools should consider for better classroom space flexibility and adaptability. Classroom space design issues when schools embrace technology are discussed, as are design considerations when rooms must accommodate different grade levels, the importance of lighting, furniture…

Evaluating students' perspectives about virtual classrooms with ...

African Journals Online (AJOL)

driving the change. In emerging economies, with an increase in the population, the cost ... Goldwater and Fogarty (2011) focused on classroom management in virtual class- rooms; and Chiu ...... business writing class. American Journal of ...

The Classroom as Stage: Impression Management in Collaborative Teaching

Science.gov (United States)

Preves, Sharon; Stephenson, Denise

2009-01-01

This article explores the social-psychological process of identity negotiation in collaborative teaching, using Erving Goffman's (1959) theoretical tradition of dramaturgy to analyze the classroom itself as a performance venue. A dramaturgical analysis of collaborative teaching is especially significant given this growing pedagogical trend because…

Classroom

Indian Academy of Sciences (India)

Classroom. In this section of Resonance, we in'Vite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or in'Vite responses, or ... "Classroom" is equally a forum for raising broader issues and .... Now we can approach the question from a different viewpoint.

Testing the Efficacy of INSIGHTS on Student Disruptive Behavior, Classroom Management, and Student Competence in Inner City Primary Grades

OpenAIRE

McClowry, Sandra Graham; Snow, David L.; Tamis-LeMonda, Catherine S.; Rodriguez, Eileen T.

2009-01-01

A prevention trial tested the efficacy of INSIGHTS into Children?s Temperament as compared to a Read Aloud attention control condition in reducing student disruptive behavior and enhancing student competence and teacher classroom management. Participants included 116 first and second grade students, their parents, and their 42 teachers in six inner city schools. Teachers completed the Sutter-Eyberg Student Behavior Inventory (SESBI) and the Teacher?s Rating Scale of Child?s Actual Competence ...

A stochastic model for the simulation of wind turbine blades in static stall

DEFF Research Database (Denmark)

Bertagnolio, Franck; Rasmussen, Flemming; Sørensen, Niels N.

2010-01-01

The aim of this work is to improve aeroelastic simulation codes by accounting for the unsteady aerodynamic forces that a blade experiences in static stall. A model based on a spectral representation of the aerodynamic lift force is defined. The drag and pitching moment are derived using...... a conditional simulation technique for stochastic processes. The input data for the model can be collected either from measurements or from numerical results from a Computational Fluid Dynamics code for airfoil sections at constant angles of attack. An analysis of such data is provided, which helps to determine...

Suppression of dynamic stall with a leading-edge slat on a VR-7 airfoil

Science.gov (United States)

Mcalister, K. W.; Tung, C.

1993-01-01

The VR-7 airfoil was experimentally studied with and without a leading-edge slat at fixed angles of attack from 0 deg to 30 deg at Re = 200,000 and for unsteady pitching motions described by alpha equals alpha(sub m) + 10 deg(sin(wt)). The models were two dimensional, and the test was performed in a water tunnel at Ames Research Center. The unsteady conditions ranged over Re equals 100,000 to 250,000, k equals 0.001 to 0.2, and alpha(sub m) = 10 deg to 20 deg. Unsteady lift, drag, and pitching-moment measurements were obtained along with fluorescent-dye flow visualizations. The addition of the slat was found to delay the static-drag and static-moment stall by about 5 degrees and to eliminate completely the development of a dynamic-stall vortex during unsteady motions that reached angles as high as 25 degrees. In all of the unsteady cases studied, the slat caused a significant reduction in the force and moment hysteresis amplitudes. The reduced frequency was found to have the greatest effect on the results, whereas the Reynolds number had little effect on the behavior of either the basic or the slatted airfoil. The slat caused a slight drag penalty at low angles of attack, but generally increased the lift/drag ratio when averaged over the full cycle of oscillation.

Experimental Methods Applied in a Study of Stall Flutter in an Axial Flow Fan

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