2,595 research outputs found

    Development and performance of IR detectors in the 1.5 to 2.4 micrometer region that operate at 240 K

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    High performance 1.5 to 2.4 micrometers (Hg,Cd)Te photodetectors for operating at 240 K or above are discussed. The detailed characterization of the detector with respect to detector temperature and background flux led to a development of an empirical model for minority carrier trapping. The concept of detective time constant is presented and successfully demonstrated by the four detectors delivered on this contract. An alternative approach is presented with the use of photovoltaic (Hg,Cd)Te detectors

    Decision support for evaluating energy demand in vinification processes using fuzzy sets theory

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    The current trend associated with high energy demand, depletion of energy reserves and low potential of renewable energy sources linked with strong industrial growth, is increasingly becoming unsustainable. As a result, production costs have increased considerably in the process industries, mainly owing to skewed energy demand and supply realities. A feasible strategy for meeting these challenges is to reduce energy consumption per unit throughput. However, to obtain a workable solution, decision makers may have to deal with energy management variables that are ambiguous, which makes solving the energy minimization problem with conventional numerical approaches very difficult. In this paper, we consider an alternative approach based on fuzzy logic to qualitatively evaluate the energy demand associated with an industrial cooling process. The model was formulated based on Mamdani fuzzy logic inferencing and implemented in MATLAB 6.5 via the Fuzzy Logic toolbox. The energy demands pertaining to specific variables were independently estimated, followed by an estimate of the overall energy consumption. The procedure is demonstrated via a case study of cooling at the maceration stage of a vinification process in the wine industry

    Evaluation of Skylab (EREP) data for forest and rangeland surveys

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    The author has identified the following significant results. Four widely separated sites (near Augusta, Georgia; Lead, South Dakota; Manitou, Colorado; and Redding, California) were selected as typical sites for forest inventory, forest stress, rangeland inventory, and atmospheric and solar measurements, respectively. Results indicated that Skylab S190B color photography is good for classification of Level 1 forest and nonforest land (90 to 95 percent correct) and could be used as a data base for sampling by small and medium scale photography using regression techniques. The accuracy of Level 2 forest and nonforest classes, however, varied from fair to poor. Results of plant community classification tests indicate that both visual and microdensitometric techniques can separate deciduous, conifirous, and grassland classes to the region level in the Ecoclass hierarchical classification system. There was no consistency in classifying tree categories at the series level by visual photointerpretation. The relationship between ground measurements and large scale photo measurements of foliar cover had a correlation coefficient of greater than 0.75. Some of the relationships, however, were site dependent

    Barriers to development and progression of women entrepreneurs in Pakistan

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    This article would help integration of women entrepreneurs into the mainstream economy in Pakistan.In Pakistan, women entrepreneurs do not enjoy the same opportunities as men due to a number of deep-rooted discriminatory socio-cultural values and traditions. Furthermore, these restrictions can be observed within the support mechanisms that exist to assist such fledgling businesswomen. The economic potential of female entrepreneurs is not being realised as they suffer from a lack of access to capital, land, business premises, information technology, training and agency assistance. Inherent attitudes of a patriarchal society, that men are superior to women and that women are best suited to be homemakers, create formidable challenges. Women also receive little encouragement from some male family members, resulting in limited spatial mobility and a dearth of social capital. The research suggests that in order to foster development, multi-agency cooperation is required. The media, educational policy makers and government agencies could combine to provide women with improved access to business development services and facilitate local, regional and national networks

    The Macrocyclic Peptide Natural Product CJ-15,208 Is Orally Active and Prevents Reinstatement of Extinguished Cocaine-Seeking Behavior

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    The macrocyclic tetrapeptide natural product CJ-15,208 (cyclo[Phe-d-Pro-Phe-Trp]) exhibited both dose-dependent antinociception and kappa opioid receptor (KOR) antagonist activity after oral administration. CJ-15,208 antagonized a centrally administered KOR selective agonist, providing strong evidence it crosses the blood–brain barrier to reach KOR in the CNS. Orally administered CJ-15,208 also prevented both cocaine- and stress-induced reinstatement of extinguished cocaine-seeking behavior in the conditioned place preference assay in a time- and dose-dependent manner. Thus, CJ-15,208 is a promising lead compound with a unique activity profile for potential development, particularly as a therapeutic to prevent relapse to drug-seeking behavior in abstinent subjects

    Weaning from Mechanical Ventilation

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    For most patients who require mechanical ventilation weaning and extubation is simple. In these patients a variety of strategies can be successful. In addition, sim ple criteria may predict when the patient is ready for extubation. For the small group of patients who require prolonged mechanical ventilation, however, contro versy exists about how best to remove ventilator sup port by weaning, and available data are sparse. Much of the controversy has centered on T-piece weaning ver sus intermittent mandatory ventilation. To date no con trolled study has demonstrated the superiority of either intermittent mandatory ventilation or T-piece weaning in difficult-to-wean patients. In the evolution of this con troversy, concern has developed over the potential for increased inspiratory work and expiratory resistance that may be associated with certain intermittent manda tory ventilation systems. The possibility that significant inspiratory work may occur during assist-control venti lation has also been demonstrated. Respiratory muscle weakness and fatigue is likely important in failure to wean. Other possible causes are failure of the cardiovas cular system and impaired ability of the lung to carry out gas exchange. In this article we first examine criteria and techniques for weaning short-term ventilator pa tients. We then examine criteria to begin the weaning process in prolonged ventilation patients, potential causes of failure to wean, and techniques that can be used to remove ventilator support from patients who are difficult to wean. Much literature has been devoted to techniques and criteria for weaning and extubation of patients from mechanical ventilation. For most patients who require ventilatory support, weaning and extuba tion can be easily accomplished by a variety of tech niques [1-4]. At one referral center 77.2% of all surviving patients were weaned from the ventilator within 72 hours of the onset of mechanical ventila tion, and 91% were weaned within 7 days [1]. Less than 10% of ventilated patients potentially posed problems in weaning from mechanical ventilation. Similarly, at a community hospital, few surviving patients required prolonged ventilatory support [2]. In easy-to-wean patients, Sahn and Lakshminarayan [5] described simple criteria that are predictive of successful discontinuation of ventilator support. For the small group of patients who require pro longed mechanical ventilation, however, minimal data are available. In these patients criteria to deter mine weaning ability or which measurements to follow are not clearly defined. Furthermore, no controlled trials are available to compare the differ ent weaning techniques proposed. In this article we first address routine weaning of the patient who has not required prolonged ventilator support. We then examine the difficult-to-wean patient and dis cuss criteria to begin the weaning process, poten tial causes of failure to wean, and available weaning techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68923/2/10.1177_088506668800300207.pd

    Spin Excitations and Sum Rules in the Heisenberg Antiferromagnet

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    Various bounds for the energy of collective excitations in the Heisenberg antiferromagnet are presented and discussed using the formalism of sum rules. We show that the Feynman approximation significantly overestimates (by about 30\% in the S=12S={1\over2} square lattice) the spin velocity due to the non negligible contribution of multi magnons to the energy weighted sum rule. We also discuss a different, Goldstone type bound depending explicitly on the order parameter (staggered magnetization). This bound is shown to be proportional to the dispersion of classical spin wave theory with a q-independent normalization factor. Rigorous bounds for the excitation energies in the anisotropic Heisenberg model are also presented.Comment: 26 pages, Plain TeX including 1 PostScript figure, UTF-307-10/9

    Anthropometry for children's clothing: difficulties and limitations

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    Children's wear lacks an anthropometric study to better fit clothes on the body of the child, providing greater comfort for users. Initially, this thesis project in fashion design intended to measure Portuguese children between the ages of 2 to 10 years, enrolled in primary schools in the region of Minho in Portugal. During the data gathering, held in the months of June, July, October and November 2016, about 600 children were scanned and measured using a 3D body scanner. The purpose of this paper is to report the difficulties and limitations experienced during data collection of the anthropometric study and the adjustments that were needed, as well as discuss some of the data collected.This work is supported by FEDER funds through the Competitive Factors Operational Program (COMPETE) POCI-01-0145-FEDER-007136 and by national funds through Portuguese Foundation for Science and Technology (FCT), under the project UID/CTM/000264.info:eu-repo/semantics/publishedVersio

    Untangling the Conceptual Isssues Raised in Reydon and Scholz’s Critique of Organizational Ecology and Darwinian Populations

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    Reydon and Scholz raise doubts about the Darwinian status of organizational ecology by arguing that Darwinian principles are not applicable to organizational populations. Although their critique of organizational ecology’s typological essentialism is correct, they go on to reject the Darwinian status of organizational populations. This paper claims that the distinction between replicators and interactors, raised in modern philosophy of biology but not discussed by Reydon and Scholz, points the way forward for organizational ecologists. It is possible to conceptualise evolving Darwinian populations providing the inheritance mechanism is appropriately specified. By this approach, adaptation and selection are no longer dichotomised, and the evolutionary significance of knowledge transmission is highlightedPeer reviewe
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