نتایج جستجو برای: centrifuge

تعداد نتایج: 2457  

2015
Ana Diaz Chris Trigg Laurence R. Young

Humans experience physiological deconditioning during space missions, primarily attributable to weightlessness. Some of these adverse consequences include bone loss, muscle atrophy, sensory-motor deconditioning, and cardiovascular alteration, which may lead to orthostatic intolerance when astronauts return to Earth. Artificial gravity could provide a comprehensive countermeasure capable of chal...

Journal: :Aviation, space, and environmental medicine 2012
Kevin R Duda Thomas Jarchow Laurence R Young

INTRODUCTION Centrifuge-induced artificial gravity (AG) with exercise is a promising comprehensive countermeasure against the physiological de-conditioning that results from exposure to weightlessness. However, body movements onboard a rotating centrifuge are affected by both the gravity gradient and Coriolis accelerations. The effect of centrifugation on squat exercise biomechanics was investi...

Journal: :پژوهش های تولید گیاهی 0
احسان اله تاجیک جلالی دانشجوی سابق کارشناسی ارشد گروه زراعت، دانشگاه آزاد گرگان علیرضا نه بندانی دانشجو گارشناسی ارشد دانشگاه علوم کشاورزی و منابع طبیعی گرگان افشین سلطانی عضو هیات علمی گروه زراعت، دانشگاه علوم کشاورزی و منابع طبیعی گرگان ابراهیم زینلی عضو هیات علمی گروه زراعت، دانشگاه علوم کشاورزی و منابع طبیعی گرگان حسین عجم نوروزی عضو هیات علمی، دانشگاه آزاد اسلامی – واحدگرگان

the increasing needs for energy, its high price and its environmental impact on greenhouse gases emission and limited energy resources due to increased research on energy balance in crop production systems. the objective of this research was to compare seedbed preparation and sowing methods in wheat production in kordkoy region with respect to energy use and efficiency. fifteen wheat fields wer...

Journal: :Annals of agricultural and environmental medicine : AAEM 2016
Zbigniew Wochyński Krzysztof Kowalczuk Marek Kłossowski Krzysztof A Sobiech

INTRODUCTION AND OBJECTIVE This study aimed at investigating the relationship between the lipid index (WS) in the examined cadets and duration of exposure to +Gz in the human centrifuge. MATERIALS AND METHODS The study involved 19 first-year cadets of the Polish Air Force Academy in Dęblin. Tests in the human centrifuge were repeated twice, i.e. prior to (test I) and 45 days after (test II). ...

Journal: :Tree physiology 2015
R B Pratt E D MacKinnon M D Venturas C J Crous A L Jacobsen

Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through me...

2008
Alexander Glaser

This article presents an analytical model, originally developed in the 1980s, for the gas centrifuge and uses this methodology to determine the main design and operational characteristics of several hypothetical centrifuge designs. A series of simulations for a typical first-generation machine is used to assess the relevance of important breakout scenarios, including batch recycling and cascade...

2014
R. F. Scott John E. Christenson

Journal: :The Journal of Experimental Medicine 1936
Johannes H. Bauer Edward G. Pickels

1. A high speed centrifuge is described in which the speed is limited only by the strength of the material of which the rotor is made. It carries sixteen tubes, each of which conveniently accommodates 7 cc. of fluid. 2. The centrifuge operates in a very high vacuum and therefore requires only a small amount of driving energy. The arrangement has been found to eliminate the possibility of produc...

2003
A. C. PALMER

A buried pipeline can buckle upwards if there is not enough resistance to movement. Both the uplift resistance (the maximum force per unit length) and the mobilisaion distance (the distance the pipeline has move before the maximum force is reached) are important in design. Tests on pipes in several soils were carried out at 1 g at full scale and in a centrifuge at 10 g and 1/10 scale. A compari...

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