نتایج جستجو برای: ultrasonic wave

تعداد نتایج: 243558  

Journal: :Zhong xi yi jie he xue bao = Journal of Chinese integrative medicine 2007
Min Wu Juan Liu Xin Zhang

OBJECTIVE To discuss the influences of the concentrations of sodium cholate, cholesterol and drug, preparation temperature, ultrasonic time and power on the particle size and encapsulation efficiency of Flos Magnoliae volatile oil nano-liposome through film-ultrasonic wave technique together with membrane filter method. METHODS The nano-liposomes were prepared by film-ultrasonic wave techniqu...

2012
A. Demčenko R. Akkerman P. B. Nagy

This work considers the characterization of linear PVC acoustic properties using a linear ultrasonic measurement technique and the non-collinear ultrasonic wave mixing technique for measurement of the physical ageing state in PVC. The immersion pulse-echo measurements were used to evaluate phase velocity dispersion and attenuation of longitudinal waves in PVC test specimens. The suggested nonco...

2004
B. Boro Djordjevic D. Cerniglia C. Cosenza

Non-contact ultrasonic, enables rapid testing of structures using ultrasonic tests that are not possible via conventional contact transducers. This paper reports on laser ultrasonic and air/gas coupled ultrasonic measurements that are performed remotely, do not require direct access to test area, do not need traditional ultrasonic coupling and do not have traditional C-scan fixture requirements...

Journal: :محیط شناسی 0
مهدی کارگر مربی مرکز تحقیقات بهداشت محیط دانشگاه علوم پزشکی گلستان امیر حسین محوی استادیار گروه مهندسی بهداشت محیط دانشگاه علوم پزشکی تهران

in biological wastewater treatment large quantities of sludge are produced. this sludge is highly putrescible.for disposal and safe usage should be stabilized. the anaerobic digestion is a standard technique for stabilization. due to the rate imiting step of sludge hydrolysis, anaerobic degradation is a slow process with high digestion time. due to high retention time and sludge dewatering prob...

Journal: :تحقیقات مهندسی کشاورزی 0
حسن ذکی دیزجی دانش آموخته دکتری مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس سعید مینایی دانشیار گروه مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس تیمور توکلی هشتجین استاد گروه مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس منیژه مختاری دیزجی دانشیار گروه فیزیک پزشکی دانشگاه تربیت مدرس

ultrasonic testing (ut), a nondestructive testing (ndt) method, is under development for quality determination of agricultural products, although it has long been used in the food industry. determination and measurement of product quality are important in modern agricultural research. noninvasive/nondestructive quality determination is a novel aspect of the postharvest process in which paramete...

2013
S. I. Rokhlin

Ultrasonic wave propagation in prestressed materials has been studied extensively in the last 40 years. Most of this work was concentrated on the effect of stress on the velocities of different types of ultrasonic waves in homogeneaus materials. Actually stresses affect not only wave velocities but also the boundary conditions at the interface. Many practical applications of ultrasonic stress c...

Journal: :The Journal of the Acoustical Society of America 2010
Christian C Anderson Adam Q Bauer Mark R Holland Michal Pakula Pascal Laugier G Larry Bretthorst James G Miller

Quantitative ultrasonic characterization of cancellous bone can be complicated by artifacts introduced by analyzing acquired data consisting of two propagating waves (a fast wave and a slow wave) as if only one wave were present. Recovering the ultrasonic properties of overlapping fast and slow waves could therefore lead to enhancement of bone quality assessment. The current study uses Bayesian...

2013
Yoshihiro Oshida Koichi Iwata Ryo Nagata Masahiro Ueda

Holographic interferometry with a phase-modulated reference beam is used to visualize a progressive ultrasonic wave in the interior of a transparent medium. The medium is illuminated with sheetlike light, and the light scattered from the plane of the light sheet is recorded in the hologram. The ultrasonic field on the plane is obtained from the reconstructed image, which provides the equiphase ...

2007
T. A. Andreeva

An experimental technique for investigation of the behavior of acoustic wave propagation through a turbulent medium is discussed. The present study utilizes the ultrasonic travel-time technique to diagnose a grid-generated turbulence. The statistics of the travel-time variations of ultrasonic wave propagation along a path are used to determine some metrics of the turbulence. Experimental data o...

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