نتایج جستجو برای: barrier
تعداد نتایج: 89945 فیلتر نتایج به سال:
performance of profiled vertical reflective parallel noise barriers with quadratic residue diffusers
the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) is used to predict the barrier insertion loss. the results of rigid and with absorptive coverage are also calculated for comparisons. using qrd on the top surface and faces of all vertical profile ...
Background and aimsThe paper presents the results of an investigation on the acoustic performance of tilted profile parallel barriers with quadratic residue diffuser tops and faces.MethodsA2D boundary element method (BEM) is used to predict the barrier insertion loss. The results of rigid and with absorptive coverage are also calculated for comparisons. Using QRD on the top surface and faces o...
most common hypotheses of seizure initiation are increased neural excitation, decreased inhibition or both. but, the conditions that lead to these activation states not to be clear yet. recent studies challenge traditional concepts and indicate new evidence that a key epileptogenic process may actually begin in the blood vessel. seizures could be initiate by a variety of insults to the brain, s...
the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) was used to predict the barrier insertion loss. the results of rigid and with absorptive coverage were also calculated for comparisons. using qrd on the top surface and faces of all vertical profil...
objective: in this article, a numerical study is conducted on mixing of two fluids in the liquid phase with two different concentrations of a chemical species in the electro-osmotic flow. methods: the base liquid is an electrolyte which flows in a two-dimensional micro-channel having electrically charged walls. lorentz electric force, which is used as stimulating flow factor, is created by appl...
background: hyperthyroidism as a risk factor for stroke is not conclusive. there are no definite data on the relationship between ischemic cerebrovascular injury and hyperthyroidism. this study was designed to define whether the outcomes of post-ischemic stroke injury are influenced by chronic hyperthyroidism. methods: two groups of hyperthyroid (ht) and control euthyroid rats of equal numbers ...
multiple sclerosis (ms) is an inflammatory disorder, in which neurons become demyelinated. to date, its etiology has remained unknown. nevertheless, certain features are inspected to provoke ms. for instance, improper function of immune cells is widely believed to be the basis of such disorder. in this concept, ms is stated as an autoimmune disease, which was asserted by major of studies, as cd...
background: family planning is a lifestyle that is selected voluntarily and is based on the knowledge, attitude and responsible decision making by couples in order to promote the health and welfare of the family and the advancement of the society. in this regard, family planning counseling plays an important role in making informed decisions if used properly and in a responsible way. detection ...
a method is described by which it is possible to determine the high barrier to ring inversion and hindered rotation by neat racemization of optically active compounds when the racemization is caused by ring inversion or hindered rotation. the method is based preparation of sufficiently pure enantiomers, mainly by chromatography on swollen microcrystalline triacetylcellulose (tac). by this techn...
In this paper, the effects of horizontal stress and dimensions of barrier pillars on the stability of drifts hr been investigated. An elastoplastic hybrid finite/boundary element program has been used. A plastic analysis of stresses in barrier pillars above the drifts in one of the underground coal mines with inclined seams is examined. Computed stresses and safety factor controur lines around ...
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