352 research outputs found
Non-equilibrium effects in fast moving plasmas
http://archive.org/details/nonequilibriumef00coopN
Electrical Conductivity, Relaxation and the Glass Transition: A New Look at a Familiar Phenomenon
Annealed samples from a single melt of a 10 mol% K2O-90SiO2 glass were reheated to temperatures ranging from 450 to 800 C, held isothermally for 20 min, and then quenched in either air or a silicon oil bath. The complex impedance of both the annealed and quenched samples was measured as a function of temperature from 120 to 250 C using ac impedance spectroscopy from 1 Hz to 1 MHz. The dc conductivity, sigma(sub dc), was measured from the low frequency intercept of depressed semicircle fits to the complex impedance data. When the sigma(sub dc) at 150 C was plotted against soak temperature, the results fell into three separate regions that are explained in terms of the glass structural relaxation time, tau(sub S). This sigma(sub dc) plot provides a new way to look the glass transition range, Delta T(sub r). In addition, sigma(sub dc) was measured for different soak times at 550 C, from which an average relaxation time of 7.3 min was calculated. It was found that the size and position of the Delta T(sub r) is controlled by both the soak time and cooling rate
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Einfluß veränderlicher Eigenschaften des Strömungsmediums auf den Massen- und Wärmetransport bei erzwungener Konvektion Teil 1. Erweiterung der von Karman-Näherung auf die laminare Strömung über eine ebene Platte mit Druckgradient Null
In Silikatschmelzen sind die Koeffizienten, die die Transportvorgänge beeinflussen, nämlich die Massendiffusion, die kinematische Viskosität und die Wärmeleitfähigkeit, stark von der Temperatur und der Zusammensetzung der Schmelze abhängig. Bei der Anwendung der Grenzschichttheorie-Gleichungen auf den Massen- und Wärmetransport in diesen Systemen ist es deshalb notwendig, mit veränderlichen Eigenschaften zu rechnen. Dies kann mit Hilfe der Integralnäherung nach von Karman für die Geschwindigkeitsverteilung in der Grenzschicht geschehen mit dem Ergebnis, daß die veränderlichen Eigenschaften im allgemeinen durch eine einfache schrittweise Näherungslösung berücksichtigt werden können; das gilt auch für den speziellen Fall der Silikatschmelzen, bei denen die kinematische Viskosität viele Größenordnungen höher ist als die Massendiffusion oder Wärmeleitfähigkeit. Der Einfluß der veränderlichen Eigenschaften kann durch numerische Integration bestimmt werden
IPM in Asia - A review of existing projects in the Philippines and Indonesia
peer reviewedIntegrated Pest Management means a pest management system that, in the context of the associated environment and the population dynamics of the pest species, utilizes ail suitable techniques and methods in as compatible a manner as possible and maintains the pest
populations at levels below those causing economically unacceptable damage or 1055.
FAO-Code- of Conduct 1984
IPM in Asia - A review of existing projects in the Philippines and Indonesia
peer reviewedIntegrated Pest Management means a pest management system that, in the context of the associated environment and the population dynamics of the pest species, utilizes ail suitable techniques and methods in as compatible a manner as possible and maintains the pest
populations at levels below those causing economically unacceptable damage or 1055.
FAO-Code- of Conduct 1984
Using Location-Allocation Algorithms to Distribute Multioutlet Hydrants in Irrigation Networks Design
Location-allocation algorithms allow for situating services in an efficient way in zones where the demand is dispersed across the area. In the present work, the minisum location-allocation algorithm is used to optimize the placement multioutlet hydrants, which are needed to supply irrigation to the region. The objective function aims to minimize the total access costs of the service. Because the total number of hydrants is the same as what currently exists the results can be compared with the presented solution. The proposed model reduces the total distance run to access the service, from 16,177 m to 13,560 m (16.17%), and the objective function (proportional to the cost) by 28.95%. © 2012 American Society of Civil Engineers.González Villa, FJ.; García Prats, A. (2011). Using Location-Allocation Algorithms to Distribute Multioutlet Hydrants in Irrigation Networks Design. Journal of Irrigation and Drainage Engineering. 274-283. doi:10.1061/(ASCE)IR.1943-4774.0000405S27428
Establishing a Low-Resource Simulation Emergency Medicine Curriculum in Nepal
Introduction
High-fidelity medical simulation is widely used in emergency medicine training because it mirrors the fast-paced environment of the emergency department (ED). However, simulation is not common in emergency medicine training programs in lower-resourced countries as cost, availability of resources, and faculty experience are potential limitations. We initiated a simulation curriculum in a low-resource environment.
Methods
We created a simulation lab for medical officers and students on their emergency medicine rotation at a teaching hospital in Patan, Nepal, with 48,000 ED patient visits per year. We set up a simulation lab consisting of a room with one manikin, an intubation trainer, and a projector displaying a simulation cardiac monitor. In this environment, we ran a total of eight cases over 4 simulation days. Debriefing was done at the end of each case. At the end of the curriculum, an electronic survey was delivered to the medical officers to seek improvement for future cases.
Results
All eight cases were well received, and learners appreciated the safe learning space and teamwork. Of note, the first simulation case that was run (the airway lab) was more difficult for learners due to lack of experience. Survey feedback included improving the debriefing content and adding further procedural skills training.
Discussion
Simulation is a valuable experience for learners in any environment. Although resources may be limited abroad, a sustainable simulation lab can be constructed and po
Autonomy of Nations and Indigenous Peoples and the Environmental Release of Genetically Engineered Animals with Gene Drives
This article contends that the environmental release of genetically engineered (GE) animals with heritable traits that are patented will present a challenge to the efforts of nations and indigenous peoples to engage in self‐determination. The environmental release of such animals has been proposed on the grounds that they could function as public health tools or as solutions to the problem of agricultural insect pests. This article brings into focus two political‐economic‐legal problems that would arise with the environmental release of such organisms. To address those challenges, it is proposed that nations considering the environmental release of GE animals must take into account the underlying circumstances and policy failures that motivate arguments for the use of the modified animals. Moreover, countries must recognize that the UN International Covenant on Civil and Political Rights and the UN International Covenant on Economic, Social and Cultural Rights place on them an obligation to ensure that GE animals with patented heritable traits are not released without the substantive consent of the nations or indigenous peoples that could be affected
Hole depletion and localization due to disorder in insulating PrBa2Cu3O7-d: a Compton scattering study
The (mostly) insulating behaviour of PrBa2Cu3O7-d is still unexplained and
even more interesting since the occasional appearance of superconductivity in
this material. Since YBa2Cu3O7-d is nominally iso-structural and always
superconducting, we have measured the electron momentum density in these
materials. We find that they differ in a striking way, the wavefunction
coherence length in PrBa2Cu3O7-d being strongly suppressed. We conclude that Pr
on Ba-site substitution disorder is responsible for the metal-insulator
transition. Preliminary efforts at growth with a method to prevent disorder
yield 90K superconducting PrBa2Cu3O7-d crystallites.Comment: 4 pages, 3 figures, revised version submitted to PR
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