1,671 research outputs found
Investigation of refracting flows for acoustic suppression
An experimental investigation to determine the possibility of using refracting flows for the suppression of aircraft inlet noise is described. Observations of wave refraction in duct flows and measurements of the increase in effectiveness of acoustic linings due to refraction have suggested methods for the design of engine inlet ducts which can either suppress noise internally or direct it to where it causes less annoyance
Design study of modification of m-1 liquid hydrogen turbopump for use in nuclear reactor test facility
Modification of M- 1 liquid hydrogen turbopump for use in Phoebus nuclear reacto
Rapid Onset Pressor Response During Isometric Exercise in Postmenopausal Hypertensive Women
Please view abstract in the attached PDF file
High Dietary Sodium Reduces Flow Mediated Dilation in Humans with Salt Sensitive & Salt Resistant BP
Please view abstract in the attached PDF file
Three-Body Dynamics and Self-Powering of an Electrodynamic Tether in a Plasmasphere
The dynamics of an electrodynamic tether in a three-body gravitational environment are investigated. In the classical two-body scenario the extraction of power is at the expense of orbital kinetic energy. As a result of power extraction, an electrodynamic tether satellite system loses altitude and deorbits. This concept has been proposed and well investigated in the past, for example for orbital debris mitigation and spent stages reentry. On the other hand, in the three-body scenario an electrodynamic tether can be placed in an equilibrium position fixed with respect to the two primary bodies without deorbiting, and at the same time generate power for onboard use. The appearance of new equilibrium positions in the perturbed three-body problem allow this to happen as the electrical power is extracted at the expenses of the plasma corotating with the primary body. Fundamental differences between the classical twobody dynamics and the new phenomena appearing in the circular restricted three-body problem perturbed by the electrodynamic force of the electrodynamic tether are shown in the paper. An interesting application of an electrodynamic tether placed in the Jupiter plasma torus is then considered, in which the electrodynamic tether generates useful electrical power of about 1 kW with a 20-km-long electrodynamic tether from the environmental plasma without losing orbital energy
The local economic development processes in low-income countries: the case of the metropolis of Chegutu in Zimbabwe
Local authorities are widely regarded as catalysts accelerating localised processes of economic development in industrialised countries but in low-income countries they are perceived as dysfunctional, inefficient and ineffective in meeting and addressing societal demands. This abstract view is however, not grounded in empirical research. As such, utilising the case of the metropolis of Chegutu a survey was designed to empirically explicate the economic processes militating its economic development. The findings are useful to policy-makers, local government authorities and management scholars. The study's unique contribution lies in its examination of the processes of local economic development in a low-income country
Long-Time Behavior of Macroscopic Quantum Systems: Commentary Accompanying the English Translation of John von Neumann's 1929 Article on the Quantum Ergodic Theorem
The renewed interest in the foundations of quantum statistical mechanics in
recent years has led us to study John von Neumann's 1929 article on the quantum
ergodic theorem. We have found this almost forgotten article, which until now
has been available only in German, to be a treasure chest, and to be much
misunderstood. In it, von Neumann studied the long-time behavior of macroscopic
quantum systems. While one of the two theorems announced in his title, the one
he calls the "quantum H-theorem", is actually a much weaker statement than
Boltzmann's classical H-theorem, the other theorem, which he calls the "quantum
ergodic theorem", is a beautiful and very non-trivial result. It expresses a
fact we call "normal typicality" and can be summarized as follows: For a
"typical" finite family of commuting macroscopic observables, every initial
wave function from a micro-canonical energy shell so evolves that for
most times in the long run, the joint probability distribution of these
observables obtained from is close to their micro-canonical
distribution.Comment: 34 pages LaTeX, no figures; v2: minor improvements and additions. The
English translation of von Neumann's article is available as arXiv:1003.213
Математична залежність точності верстатних пристроїв від їх ступеня гнучкості
Підвищення конкурентоспроможності продукції, що виробляється
невеликими підприємствами, забезпечується шляхом скорочення витрат на
проектування та виготовлення технологічної оснастки для свердлильно-
фрезерно-розточувальних операцій. Це стає можливим за рахунок
використання гнучких верстатних пристроїв (ВП), що мають можливість
переналагодження у заданому діапазоні розмірів заготовки шляхом
регулювання установлювально-затискних елементів
Microvascular Function Is Reduced In Normotensive Salt-Sensitive Individuals Independent of Dietary Sodium Intake
Please view abstract in the attached PDF file
Zinc Intake and Biochemical Markers of Bone Turnover in Type 1 Diabetes
OBJECTIVE—To examine the relationship between Zn nutritive status and biochemical markers of bone turnover in type 1 diabetes
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