A numerical study is performed to investigate flow instability phenomena in a square channel with steady, laminar throughflow. The channel rotates around an axis perpendicular to…
Abstract
A numerical study is performed to investigate flow instability phenomena in a square channel with steady, laminar throughflow. The channel rotates around an axis perpendicular to the channel longitudinal axis. The flow field extends from the channel entrance to a distance of 120 to 600Dh. The range of Reynolds number is Re = 300−2000. The inlet flow velocity is assumed uniform. Surface vorticity intensity is introduced to indicate the variation of vortices. It is revealed that at intermediate Reynolds numbers (680 > Re > 300), the flow is characterized by three vortex patterns: at slow rotation there is one vortex pair; at intermediate rotation a secondary vortex, in addition to the original vortex, emerges near the trailing wall and then breaks down downstream; and at rapid rotation the secondary vortex does not exist with the flow being restabilized to form a single‐pair vortex pattern. At low Reynolds numbers (Re ≤ 300), the flow exhibits a single‐pair vortex pattern, while at high Reynolds numbers (Re ≥ 680), the flow experiences the emergence and breakdown of a secondary vortex, but no restabilization is found with an increase in the rotational speed. It is also disclosed that the variation of the vortices is related to the distance from the inlet.
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SHIN FANN, WEN‐JEI YANG and S. MOCHIZUKI
A theoretical study is performed on three‐dimensional, heat transfer and fluid flow in radially rotating heated channels with steady, laminar throughflow. Consideration is given…
Abstract
A theoretical study is performed on three‐dimensional, heat transfer and fluid flow in radially rotating heated channels with steady, laminar throughflow. Consideration is given to the channel of different geometry. Both the rotational speed and throughflow rate are varied. The flow is hydrodynamically and thermally developing, with a constant wall heat flux. The velocity‐vorticity method is employed in the formulation and numerical results are obtained by means of a finite‐difference technique. The Nusselt number, friction factor, and temperature and velocity distributions are determined, and the role of the Coriolis force on the entrance‐region transport phenomena is investigated. Results are compared with the existing literature.
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Soo Min Shin, Song Soo Lim and Yongsung Cho
This study aimed to estimate the economic benefits of PM2.5 emission abatement by Red Pine, Pinus Koraiensis and Quercus, using a metering model analyzing the amount of PM2.5…
Abstract
Purpose
This study aimed to estimate the economic benefits of PM2.5 emission abatement by Red Pine, Pinus Koraiensis and Quercus, using a metering model analyzing the amount of PM2.5 absorption in Korea.
Design/methodology/approach
To estimate the economic effects of PM2.5 adsorptions by trees, the frequency of hospital visits resulting from respiratory and circulatory diseases was estimated using a Probit model based on the data from National Health and Nutrition Survey.
Findings
The results show that Quercus and Pinus Koraiensis absorb and eliminate the largest amount of PM2.5. Reducing 1 ton of PM2.5 emission through the planting of trees leads to lower incidences of respiratory and circulatory diseases equivalent to the amount of 95 million won. When the trees planted are 2-year-old Red Pine, Pinus Koraiensis and Quercus, the resulting economic benefits of the PM2.5 abatement would amount to 481 million won, 173 million won and 1,027 million won, respectively. If the trees are 80 years old, the economic benefits are estimated to be 73 billion won for Red Pine, 103 billion won for Pinus Koraiensis and 38 billion won for Quercus.
Research limitations/implications
One limitation of this study is that the weight of PM2.5 adsorbed by each leaf area entirely depended on the experimental results from a prior study and the values are likely to be different from those actually absorbed in natural surroundings. In addition, because of the lack of data from a domestic survey on the surface of leaf area or the reload flow rate of PM2.5, this study referred to data from foreign research. Unfortunately, this specific data may not reflect climatic and terrain characteristics specific to the target country. We used the annual wind speed to calculate the reload flow rate and elimination volume; however, the figures could be more accurate with hourly or daily climate variations. When estimating the health benefits of changes in PM2.5 emissions on respiratory and circulatory diseases, more segmented access to patients' hospital visits and hospital admissions are desirable. Finally, the study focused on the three major tree species of Korea, however, a more detailed study of PM2.5 reduction by various tree types is needed in the future.
Originality/value
This paper quantitatively assessed the amount of PM2.5 adsorption by each of the three tree species. Then, the economic benefits were calculated in terms of how much money would be saved on hospital visits thanks to the reduced PM2.5 levels and lower incidences of respiratory and circulatory system diseases. The net contribution of this study was to prove the trees' function of reducing PM2.5 as it relates to human health. We focused on the most common trees in Korea and compared them to provide new information on the species.
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Julie Hardaker, Suzette Dyer, Fiona Hurd and Mark Harcourt
This study aims to explore the experience of performing androgynous leadership approaches by New Zealand women leaders within the context of everyday conflict situations.
Abstract
Purpose
This study aims to explore the experience of performing androgynous leadership approaches by New Zealand women leaders within the context of everyday conflict situations.
Design/methodology/approach
The research question “How do women leaders experience gender in conflict situations?” was explored through the facilitation of 4 focus groups with 19 senior female leaders in New Zealand. Poststructural discourse analysis was used to explore how participants negotiated positions of power within their environments and in accordance with competing gendered discourses.
Findings
Participants described taking a flexible, balanced, androgynous leadership approach to managing conflict situations. While the expectations to be “empathetic”, “sympathetic”, “gentle”, “nurturing” and “caring” resonated with the participants preferred approach, they remained firm that if conflict persisted, they would “cross the line” and adopt stereotypically masculine behaviours to resolve the situation. However, participants describe that when perceived to be crossing the line from feminine to masculine approaches, they experienced significant backlash. This demonstrates the tensions between the approaches women leaders would like to take in managing conflict and the experiences of doing so within a prescriptively gendered organisational context.
Originality/value
This research contributes to a gap which exists in understanding how gender is experienced from the viewpoint of the woman leader. This research presents a nuanced view of gendered leadership as a contested ground, rather than a series of strategic choices. Despite an increase in the acceptance of women into leadership positions, the authors seemingly remain bound by what is considered a “feminine” leader.
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This paper investigates the relationship between scanning and planning, planning and TQM practices, and scanning and TQM practices by collecting primary data from 54 small and…
Abstract
This paper investigates the relationship between scanning and planning, planning and TQM practices, and scanning and TQM practices by collecting primary data from 54 small and medium‐sized enterprises (SMEs) through questionnaire in the Republic of Botswana. Being explanatory in nature, the study used only descriptive statistics to analyze the data and indicate the nature and direction of the relationship. The study found a statistically significant relationship between scanning and planning; and between planning and TQM practices. However, scanning is indirectly related to TQM and has a moderating impact on TQM practices. Important implications of the findings for practitioners, future research and SME support agencies are also provided.
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Rune Dall Jensen, Sissel Ravn and Mette Krogh Christensen
Education of the surgeon and development of surgical expertise have been debated for centuries. Today, research in surgical education applies terms and methods from other…
Abstract
Purpose
Education of the surgeon and development of surgical expertise have been debated for centuries. Today, research in surgical education applies terms and methods from other performance domains such as sport and music. However, there still seems to be a lack of consensus as to how talent may be brought into the discourse about surgical education. Especially, when it comes to identifying and developing trainees who in the future will perform better than the average surgeon.
Design/methodology/approach
This five-step scoping study aims to map existing literature about talent identification, talent development and development of expertise in the domains of surgery, sport and music in the period of 1985-2014.
Findings
A total of 242 studies, divided in the four domains of surgery (69 studies), sport (115 studies), music (34 studies) and cross-disciplinary studies (24 studies) published in the period 1985-2014 were included.
Originality/value
Informed by the performance domains of sports and music and their inclusion of a holistic, ecological approach to research, this study suggests that research in surgical education may benefit from broadening its view on talent by including psychosocial variables and environmental, demographic and structural influencers when considering how surgical talent may be identified and developed.
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Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the metal is…
Abstract
Sheet metal forming is a process of shaping thin sheets of metal by applying pressure through male or female dies or both. In most of used sheet‐formating processes the metal is subjected to primarily tensile or compressive stresses or both. During the last three decades considerable advances have been made in the applications of numerical techniques, especially the finite element methods, to analyze physical phenomena in the field of structural, solid and fluid mechanics as well as to simulate various processes in engineering. These methods are useful because one can use them to find out facts or study the processes in a way that no other tool can accomplish. Finite element methods applied to sheet metal forming are the subjects of this paper. The reason for writing this bibliography is to save time for readers looking for information dealing with sheet metal forming, not having an access to large databases or willingness to spend own time with uncertain information retrieval. This paper is organized into two parts. In the first one, each topic is handled and current trends in the application of finite element techniques are briefly mentioned. The second part, an Appendix, lists papers published in the open literature. More than 900 references to papers, conference proceedings and theses/dissertations dealing with subjects that were published in 1995‐2003 are listed.
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While prior research has established that traumatic brain injury (TBI) is a risk factor for violent offending, there is little understanding of mechanisms that may underpin this…
Abstract
Purpose
While prior research has established that traumatic brain injury (TBI) is a risk factor for violent offending, there is little understanding of mechanisms that may underpin this relationship. This is problematic, as a better understanding of these mechanisms could facilitate more effective targeting of treatment. This study aims to address these gaps in the extant literature by examining TBI as a predictor of violent offending and test for mediation effects through cognitive constructs of dual systems imbalance and hostility among a sample of justice-involved youth (JIY).
Design/methodology/approach
The Pathways to Desistance data were analyzed. The first three waves of this data set comprising the responses of 1,354 JIY were analyzed. Generalized structural equation modeling was used to test for direct and indirect effects of interest. A bootstrap resampling process was used to compute unbiased standard errors for determining the statistical significance of mediation effects.
Findings
Lifetime experience of TBI was associated with increased violent offending frequency at follow-up. Hostility significantly mediated this relationship, but dual systems imbalance did not. This indicated that programming focused on reducing hostility among JIY who have experienced TBI could aid in reducing violent recidivism rates.
Originality/value
To the best of the author’s knowledge, this study was the first to identify significant mediation of the relationship between TBI and violent offending through hostility.
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Brent Lagesse, Shuoqi Wang, Timothy V. Larson and Amy Ahim Kim
The paper aims to develop a particle matter (PM2.5) prediction model for open-plan office space using a variety of data sources. Monitoring of PM2.5 levels is not widely applied…
Abstract
Purpose
The paper aims to develop a particle matter (PM2.5) prediction model for open-plan office space using a variety of data sources. Monitoring of PM2.5 levels is not widely applied in indoor settings. Many reliable methods of monitoring PM2.5 require either time-consuming or expensive equipment, thus making PM2.5 monitoring impractical for many settings. The goal of this paper is to identify possible low-cost, low-effort data sources that building managers can use in combination with machine learning (ML) models to approximate the performance of much more costly monitoring devices.
Design/methodology/approach
This study identified a variety of data sources, including freely available, public data, data from low-cost sensors and data from expensive, high-quality sensors. This study examined a variety of neural network architectures, including traditional artificial neural networks, generalized recurrent neural networks and long short-term memory neural networks as candidates for the prediction model. The authors trained the selected predictive model using this data and identified data sources that can be cheaply combined to approximate more expensive data sources.
Findings
The paper identified combinations of free data sources such as building damper percentages and weather data and low-cost sensors such as Wi-Fi-based occupancy estimator or a Plantower PMS7003 sensor that perform nearly as well as predictions made based on nephelometer data.
Originality/value
This work demonstrates that by combining low-cost sensors and ML, indoor PM2.5 monitoring can be performed at a drastically reduced cost with minimal error compared to more traditional approaches.