1,221 research outputs found
Plasma actuator: influence of dielectric surface temperature
Plasma actuators have become the topic of interest of many researchers for the purpose of flow control. They have the advantage of manipulating the flow without the need for any moving parts, a small surface profile which does not disturb the free stream flow, and the ability to switch them on or off depending on the particular situation (active flow control). Due to these characteristics they are becoming very popular for flow control over aircraft wings. The objective of the current study is to examine the effect of the actuator surface temperature on its performance. This is an important topic to understand when dealing with real life aircraft equipped with plasma actuators. The temperature variations encountered during a flight envelope may have adverse effects in actuator performance. A peltier heater along with dry ice are used to alter the actuator temperature, while particle image velocimetry (PIV) is utilised to analyse the flow field. The results show a significant change in the induced flow field by the actuator as the surface temperature is varied. It is found that for a constant peak-to-peak voltage the maximum velocity produced by the actuator depends directly on the dielectric surface temperature. The findings suggest that by changing the actuator temperature the performance can be maintained or even altered at different environmental conditions
Achieving Effective Antidepressant Pharmacotherapy in Primary Care: The Role of Depression Care Management in Treating Late-Life Depression
To estimate the effect of an evidence-based depression care management (DCM) intervention on the initiation and appropriate use of antidepressant in primary care patients with late-life depression. DESIGN : Secondary analysis of data from a randomized trial. SETTING : Community, primary care. PARTICIPANTS : Randomly selected individuals aged 60 and older with routine appointments at 20 primary care clinics randomized to provide a systematic DCM intervention or care as usual. METHODS : Rates of antidepressant use and dose adequacy of patients in the two study arms were compared at each patient assessment (baseline, 4, 8, and 12 months). For patients without any antidepressant treatment at baseline, a longitudinal analysis was conducted using multilevel logistic models to compare the rate of antidepressant treatment initiation, dose adequacy when initiation was first recorded, and continued therapy for at least 4 months after initiation between study arms. All analyses were conducted for the entire sample and then repeated for the subsample with major or clinically significant minor depression at baseline. RESULTS : Rates of antidepressant use and dose adequacy increased over the first year in patients assigned to the DCM intervention, whereas the same rates held constant in usual care patients. In longitudinal analyses, the DCM intervention had a significant effect on initiation of antidepressant treatment (adjusted odds ratio (OR)=5.63, P <.001) and continuation of antidepressant medication for at least 4 months (OR=6.57, P =.04) for patients who were depressed at baseline. CONCLUSIONS : Evidence-based DCM models are highly effective at improving antidepressant treatment in older primary care patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66406/1/j.1532-5415.2009.02226.x.pd
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Introduction to Special Issue on PV Systems Performance and Reliability
The papers in this special issue have been selected from the systems and balance-of- systems sessions at the 1998 Photovoltaic Performance and Reliability Workshop. The workshop was held November 3-5, 1998 and hosted by the Florida Solar Energy Center, Cocoa Beach, Florida under sponsorship of the US National Center for Photovoltaics (National Renewable Energy Laboratory and Sandia National Laboratories). The topics and issues addressed by these papers were identified in an invited review paper on PV systems by the guest editors. Their work was published earlier this year in Volume 7, Number 1 of Progress in Photovoltaics ('Photovoltaic Systems: An End-of-Millennium Review'). Experts in the PV community were asked to make presentations on these topics at the workshop. The papers that follow are the results of that effort. The papers are organized by topic: (1) codes and standards; (2) reliability; (3) design issues; and (4) commercialization
Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective
This essay is inspired by the ideas and research examined in the special section on “Stakeholder Marketing” of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing “prosociety” and “proenvironment” perspectives—orientations that are also in keeping with the public policy focus of this journal. Under the “hard form” of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society
Simulating industrial scenarios with the open-source software MercuryDPM
Creating predictive computer simulations, i.e. virtual prototypes, of complex granular industrial processes has many challenges. In this paper we review recent advances in creating such virtual prototypes. We introduce the open-source code MercuryDPM [1], which is often applied to complex industrial applications via the spin-off company MercuryLab. We briefly discuss how to import complex industrial geometries and how to deal with large numbers of particles and wide size-distributions. Then we focus on how to create a computer representation of an actual granular material, the so-called model calibration. For calibration, we start by reviewing what parameters need to be measured and what experimental characterisation machines are available. We present an industrially practical calibration method, where certain parameters are directly measured and others are indirectly calibrated, using a variety of machine-learning techniques, implemented in the open-source codes GrainLearning [2], TensorFlow [3] and scikit-learn [4]. With GrainLearning, one can find local optima in only two to three iterations, even for complex contact models with many microscopic parameters. On the other hand, TensorFlow and scikit-learn use two popular supervised learning algorithms, Neural Network (NN) and Random Forest (RF) regression, respectivly. After a training period consisting of hundreds of particle simulations, NN and RF are capable of providing a mapping between the micro-parameters and the bulk behaviour, which can be used to find the optimal micro-parameters that correspond to the experimentally observed behaviour
Test-retest reliability and effects of repeated testing and satiety on performance of an Emotional Test Battery
The P1vital® Oxford Emotional Test Battery (ETB) comprises five computerized tasks designed to assess cognition and emotional processing in human participants. It has been used in between-subjects experimental designs; however, it is unclear whether the battery can be used in crossover designs. This is of particular importance given the increasing use of ETB tasks for repeated assessment of depressed patients in clinical trials and clinical practice. In addition, although satiety state has been reported to affect performance on some cognitive and emotional tasks, it is not known whether it can influence performance on the ETB. Two studies explored these issues. In Experiment 1, 30 healthy women were tested on the ETB on 4 separate occasions (each a week apart) in a within-subjects design. In Experiment 2, another 30 healthy women were randomized to either a satiated or a hungry condition, where they were given an ad libitum lunch of cheese sandwiches, before (satiated) or after (hungry) they were asked to complete the ETB. Experiment 1 demonstrated good test-retest reliability for the ETB. One of the tasks was free from practice effects, whilst performance on the other four tasks stabilized after the first two sessions. In Experiment 2, eating to satiety only affected performance on a single ETB task. These results suggest that the ETB can be used in crossover designs after two initial training sessions. Further, as a robust satiety manipulation had only a limited effect on a single ETB task, it is unlikely that appetitive state will confound ETB performance
Fusion In The Era Of Burning Plasma Studies: Workforce Planning For 2004-2014
This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Raymond Orbach (Appendix A), asking FESAC to addressed the issue of workforce development in the U.S. fusion program. This report, submitted to FESAC March 29, 2004 and subsequently approved by them (Appendix B), presents FESAC\u27s response to that charge
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