نتایج جستجو برای: acoustic barriers

تعداد نتایج: 166440  

Journal: :جنگل و فرآورده های چوب 0
حوری شریف نیا دانشگاه تربیت مدرس سعید کاظمی نجفی گروه علوم و صنایع چوب و کاغذ، دانشکده منابع طبیعی ، دانشگاه تربیت مدرس مهدی احمدی نجف آبادی دانشگاه صنعتی امیر کبیر

with the aim of identifying failure mechanism in oriented strand boards, failure behavior of wood strands under tensile load was investigated using acoustic emission technique. resinated and unresinated strands were arranged at top, middle and bottom section of the board before pressing. tensile and acoustic emission tests were performed simultaneously on treated and control samples. using tens...

Journal: :iranian journal of otorhinolaryngology 0
mohammad faraji rad department of neurosurgery, mashhad university of medical sciences, mashhad, iran

acoustic neuromas (an) are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(vs) causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. in many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by mri. in the majority of cases the tumor is s...

2010
Lingyu Yu Victor Giurgiutiu Paul Ziehl Didem Ozevin Patrick Pollock

Piezoelectric wafer active sensors (PWAS) are well known for its dual capabilities in structural health monitoring, acting as either actuators or sensors. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In our research, our use of the PWAS based sensing has the novelty of...

Journal: :international journal of automotive engineering 0
r. noorpoor sadighzadeh habibnejad

diesel exhaust particles are a complex mixture of thousands of gases and fine substances that contain more than 40 different environmental contaminants. being exposed to these exhaust particles (called soot) can cause lung damage and respiratory problems. diesel particulate filters are used in many countries for mobile sources as a legal obligation to decrease harmful effect of these fine parti...

Journal: :پژوهش و برنامه ریزی در آموزش عالی 0
سید مجید عبداللهی magid abdellahi phd student of distance education planning at the payamnoor universityدانشجوی دکتری برنامه ریزی آموزش از راه دور،دانشگاه پیام نور تهران بی بی عشرت زمانی bibi eshrat zamani psychology and education at the university of isfahanدانشکده روانشناسی و علوم تربیتی دانشگاه اصفهان عیسی ابراهیم زاده isa 1ebrahim zadeh of humanities at the university of payamnoor, tehranدانشکده علوم انسانی دانشگاه پیام نور تهران حسین زارع hossein zaree of humanities at the university of payamnoor, tehranدانشکده علوم انسانی دانشگاه پیام نور تهران بهمن زندی bahman zandi of humanities at the university of payamnoor, tehranدانشکده علوم انسانی دانشگاه پیام نور تهران

the present research identified major barriers of isfahan university teachers participation in electronic technology courses. a second goal of this study was to examine the effects of characteristics and demographics of university teachers on these barriers. in this research problems and barriers fell into three distinct categories: personal, perceptual, and contextual. a questionnaire was desi...

2013
Nic J. de Vries Febe de Wet

Mobile-assisted language learning applications (MALL) has significant potential in the developing world where access to teachers and classrooms are real barriers to learning. This demonstration of an Android-based mobile language learning application is used to teach vocabulary and employs off-line Automatic Speech Recognition (ASR) and Text-to-speech (TTS) technologies with custom-built langua...

Journal: :JCM 2011
Stanley J. Barr Jie Wang Benyuan Liu

Anti-submarine warfare(ASW) is a critical challenge for maintaining a fleet presence in hostile areas. Technology advancement has allowed submarines to evade standard sonar detection. A viable alternative is to place magnetic or acoustic sensors in close proximity to possible underwater pathways of submarines. This approach may require deploying large-scale underwater sensor networks to form 3-...

Journal: :Micromachines 2021

Acoustic metamaterials are large-scale materials with small-scale structures. These structures allow for unusual interaction propagating sound and endow the material exceptional acoustic properties not found in normal materials. However, their multi-scale nature means that manufacture of these is trivial, often requiring micron-scale resolution over centimetre length scales. In this review, we ...

An efficient finite volume approach has been used to develop a three dimensional Helmholtz acoustic solver for complex geometries. This acoustic solver was utilized to obtain characteristic mode shapes and frequencies of a baffled combustion chamber. An experimental setup, including stationary and moving sensors, has also been used to measure these quantities for the same model combustion chamb...

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