scholarly journals The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

Fluids ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
James Yang ◽  
Patrik Andreasson ◽  
Penghua Teng ◽  
Qiancheng Xie

Most of the hydropower dams in Sweden were built before 1980. The present dam-safety guidelines have resulted in higher design floods than their spillway discharge capacity and the need for structural upgrades. This has led to renewed laboratory model tests. For some dams, even computational fluid dynamics (CFD) simulations are performed. This provides the possibility to compare the spillway discharge data between the model tests performed a few decades apart. The paper presents the hydropower development, the needs for the ongoing dam rehabilitations and the history of physical hydraulic modeling in Sweden. More than 20 spillways, both surface and bottom types, are analyzed to evaluate their discharge modeling accuracy. The past and present model tests are compared with each other and with the CFD results if available. Discrepancies do exist in the discharges between the model tests made a few decades apart. The differences fall within the range −8.3%–+11.2%. The reasons for the discrepancies are sought from several aspects. The primary source of the errors is seemingly the model construction quality and flow measurement method. The machine milling technique and 3D printing reduce the source of construction errors and improve the model quality. Results of the CFD simulations differ, at the maximum, by 3.8% from the physical tests. They are conducted without knowledge of the physical model results in advance. Following the best practice guidelines, CFD should generate results of decent accuracy for discharge prediction.

2020 ◽  
Vol 9 (2) ◽  
pp. 82-90
Author(s):  
Matthew J. Pesko

Anxiety disorders are commonly experienced by college and university students and should be routinely assessed in mental health settings. Epidemiological studies suggest that the burden of these illnesses has greatly expanded even over the past decade. Factors that contribute to the experience of an anxiety disorder in a young adult student population are considered herein. The best practice for evaluation and treatment of these disorders is presented based on the review of available literature in this field. Special attention is paid to the concept of resilience as it pertains to anxiety disorders in the student population.


No other talent process has been the subject of such great debate and emotion as performance management (PM). For decades, different strategies have been tried to improve PM processes, yielding an endless cycle of reform to capture the next “flavor-of-the-day” PM trend. The past 5 years, however, have brought novel thinking that is different from past trends. Companies are reducing their formal processes, driving performance-based cultures, and embedding effective PM behavior into daily work rather than relying on annual reviews to drive these. Through case studies provided from leading organizations, this book illustrates the range of PM processes that companies are using today. These show a shift away from adopting someone else’s best practice; instead, companies are designing bespoke PM processes that fit their specific strategy, climate, and needs. Leading PM thought leaders offer their views about the state of PM today, what we have learned and where we need to focus future efforts, including provocative new research that shows what matters most in driving high performance. This book is a call to action for talent management professionals to go beyond traditional best practice and provide thought leadership in designing PM processes and systems that will enhance both individual and organizational performance.


Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 9
Author(s):  
John H. Graham

Best practices in studies of developmental instability, as measured by fluctuating asymmetry, have developed over the past 60 years. Unfortunately, they are haphazardly applied in many of the papers submitted for review. Most often, research designs suffer from lack of randomization, inadequate replication, poor attention to size scaling, lack of attention to measurement error, and unrecognized mixtures of additive and multiplicative errors. Here, I summarize a set of best practices, especially in studies that examine the effects of environmental stress on fluctuating asymmetry.


Dermatology ◽  
2021 ◽  
pp. 1-10
Author(s):  
Yaron Har-Shai ◽  
Lior Har-Shai ◽  
Viktor A. Zouboulis ◽  
Christos C. Zouboulis

<b><i>Background:</i></b> Auricular keloids belong to the most perplexing medical conditions, which have significant psychosocial impact on the patient’s body image and quality of life. <b><i>Summary:</i></b> The article is purposed to provide dermatologists and plastic surgeons with the best proven practice using intralesional cryosurgery for the treatment of the different auricular keloid types in order to obtain superior clinical results by minimizing the probability of recurrence. In the past 20 years, the authors have developed novel procedures in order to increase the effectiveness of intralesional cryosurgery on auricular keloids, including hydrodissection, warm gauze technique, and excision of dangling skin. Long-lasting clinical results with a low recurrence rate and a satisfactory aesthetic outcome are achieved with no deformation of the ear framework.


Author(s):  
Andrew Cornett

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.


Author(s):  
Paula Corabian ◽  
Bing Guo ◽  
Carmen Moga ◽  
N. Ann Scott

AbstractObjectivesThis article retrospectively examines the evolution of rapid assessments (RAs) produced by the Health Technology Assessment (HTA) Program at the Institute of Health Economics over its 25-year relationship with a single requester, the Alberta Health Ministry (AHM).MethodsThe number, types, and methodological attributes of RAs produced over the past 25 years were reviewed. The reasons for developmental changes in RA processes and products over time were charted to document the push–pull tension between AHM needs and the HTA Program's drive to meet those needs while responding to changing methodological benchmarks.ResultsThe review demonstrated the dynamic relationship required for HTA researchers to meet requester needs while adhering to good HTA practice. The longstanding symbiotic relationship between the HTA Program and the AHM initially led to increased diversity in RA types, followed by controlled extinction of the less fit (useful) “transition species.” Adaptations in RA methodology were mainly driven by changes in best practice standards, requester needs, the healthcare environment, and staff expertise and technology.ConclusionsRAs are a useful component of HTA programs. To remain relevant and useful, RAs need to evolve according to need within the constraints of HTA best practice.


Author(s):  
Charles Lefevre ◽  
Yiannis Constantinides ◽  
Jang Whan Kim ◽  
Mike Henneke ◽  
Robert Gordon ◽  
...  

Vortex-Induced Motion (VIM), which occurs as a consequence of exposure to strong current such as Loop Current eddies in the Gulf of Mexico, is one of the critical factors in the design of the mooring and riser systems for deepwater offshore structures such as Spars and multi-column Deep Draft Floaters (DDFs). The VIM response can have a significant impact on the fatigue life of mooring and riser components. In particular, Steel Catenary Risers (SCRs) suspended from the floater can be sensitive to VIM-induced fatigue at their mudline touchdown points. Industry currently relies on scaled model testing to determine VIM for design. However, scaled model tests are limited in their ability to represent VIM for the full scale structure since they are generally not able to represent the full scale Reynolds number and also cannot fully represent waves effects, nonlinear mooring system behavior or sheared and unsteady currents. The use of Computational Fluid Dynamics (CFD) to simulate VIM can more realistically represent the full scale Reynolds number, waves effects, mooring system, and ocean currents than scaled physical model tests. This paper describes a set of VIM CFD simulations for a Spar hard tank with appurtenances and their comparison against a high quality scaled model test. The test data showed considerable sensitivity to heading angle relative to the incident flow as well as to reduced velocity. The simulated VIM-induced sway motion was compared against the model test data for different reduced velocities (Vm) and Spar headings. Agreement between CFD and model test VIM-induced sway motion was within 9% over the full range of Vm and headings. Use of the Improved Delayed Detached Eddy Simulation (IDDES, Shur et al 2008) turbulence model gives the best agreement with the model test measurements. Guidelines are provided for meshing and time step/solver setting selection.


Author(s):  
Seema S.Ojha

History is constructed by people who study the past. It is created through working on both primary and secondary sources that historians use to learn about people, events, and everyday life in the past. Just like detectives, historians look at clues, sift through evidence, and make their own interpretations. Historical knowledge is, therefore, the outcome of a process of enquiry. During last century, the teaching of history has changed considerably. The use of sources, viz. textual, visual, and oral, in school classrooms in many parts of the world has already become an essential part of teaching history. However, in India, it is only a recent phenomenon. Introducing students to primary sources and making them a regular part of classroom lessons help students develop critical thinking and deductive reasoning skills. These will be useful throughout their lives. This paper highlights the benefits of using primary source materials in a history classroom and provides the teacher, with practical suggestions and examples of how to do this.


Author(s):  
Tom Thatcher

Discussions of the authorship of the Gospel of John must answer two questions: who is the Beloved Disciple who is portrayed as the book’s primary source of information, and how is this individual related to the author, John the evangelist? On the first question, scholars are divided on whether the Beloved Disciple is a real historical individual or an ideal symbolic figure. Data from the text itself and from social-science perspectives on the reputations of key figures from the past suggest that both are correct: the Beloved Disciple was a legendary associate of Jesus whose presentation reflects his reputation as a source of information that was critical to the Johannine theological outlook. On the second question, data suggests that the evangelist was not the Beloved Disciple but rather a disciple of that individual, perhaps basing his own book on an earlier document produced by the Beloved Disciple.


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