نتایج جستجو برای: acoustic barriers
تعداد نتایج: 166440 فیلتر نتایج به سال:
Carbon / epoxy composite is one of the most useful polymer matrix composites that has special properties such as high strength-to-weight ratio, high hardness, high corrosion resistance, Resistance to nuclear radiation has high consumption in different industries such as aerospace industry. Therefor monitoring of loading of this type of composite is important. In order to determine failure mecha...
Introduction: Reducing noise pollution has become an essential issue due to the increase in public concern and also social demands for a better lifestyle. Using sound absorption materials is a preferred method to reduce the noise pollution. Undesirable properties of pure polyurethane such as poor absorption of mechanical energy in narrow frequency ranges can be improved by providing polymeric n...
In this study, the longitudinal and hoop tensile strengths of an industrial ±55° Glass Reinforced Epoxy (GRE) pipe with eighteen layers as well as the associated failure mechanisms are determined. To obtain the longitudinal and hoop tensile strengths values, three specimens are cut from the studied GRE pipe in each direction. A comparison is done between both the strength values, and the fractu...
Sonic crystal acoustic screens have been in progressive research and development the last two decades as a technical solution for mitigating traffic noise. Their behaviour is quite different from that observed classical barriers, with latter being based on physically blocking direct sound propagation path (only allowing diffracted noise to reach sensible receivers), sonic crystals providing att...
introduction: some of the studies have shown that ra (rheumatoid arthritis) may cause hearing disorders. these disorders can result in problems later in life, so survey of correlation between rheumatoid arthritis and hearing disorders is important . methods: this was a case-control study which has done from december 2004 to august 2006 at shaheed sadoughi hospital in yazd. in this study, 50 rhe...
ra (rheumatoid arthritis) is a chronic multisystem disease with a variety of systemic manifestations. one of these manifestations, is hearing disorder, so study of the relation between ra and hearing disorders is seem important. this was a case-control study which has done from december 2004 to august 2006. this study compared 50 patients with ra, with age, sex and job-matched as control. audio...
Objective Stuttering is a developmental disorder of speech fluency with unknown causes. One of the proposed theories in this field is deficits in speech motor control that is associated with damaged control, timing, and coordination of the speech muscles. Fundamental frequency, fundamental frequency range, intensity, intensity range, and voice onset time are the most important acoustic componen...
Evidence and previous research results indicate that many barriers have affected the success of entrepreneurs in dairy industry. The main objective of this paper is to identify and prioritize the barriers to entrepreneurship development in dairy farming in southern Khorasan province. The statistical population of this study, in the Delphi method, was knowledgeable experts, among whom 15 experts...
Introduction: Despite the diffusion of information technology, especially in the health care domain, the development process and use of Electronic Health Record is still difficult; consequently, it is important to identify and eliminate barriers to implementing this system, and adopt effective implementation approaches. This study therefore aimed to determine the barriers to implementing Electr...
the removal of fine particles less than 2.5 μm in diameter generated from industrial plantsrepresents a serious challenge in air pollution abatement. these particles can penetrate deeply into the lungs and are difficult to remove by cyclones, electrostatic precipitators, and other conventional separation devices. in this paper, the influence of acoustic waves on removing aerosol particles from ...
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