scholarly journals Relations between acoustic cavitation and skin resistance during intermediate- and high-frequency sonophoresis

2014 ◽  
Vol 194 ◽  
pp. 266-277 ◽  
Author(s):  
Kyle T. Rich ◽  
Cameron L. Hoerig ◽  
Marepalli B. Rao ◽  
T. Douglas Mast
Keyword(s):  
High Frequency ◽  
Skin Resistance ◽  
Acoustic Cavitation

scholarly journals Study of the effect of high-frequency acoustic cavitation on the quality of raw milk and dairy products based on it

2019 ◽  
Vol 81 (3) ◽  
pp. 145-150
Author(s):  
K. A. Kanina ◽  
O. N. Krasulya ◽  
N. A. Zhizhin ◽  
E. S. Semenova
Keyword(s):  
High Frequency ◽  
Dairy Products ◽  
Raw Materials ◽  
Acoustic Cavitation ◽  
Raw Milk ◽  
Raw Material ◽  
Coliform Bacteria ◽  
Cow’S Milk ◽  
Cow's Milk

The article presents the results of studies obtained in the study of the quality of milk processed with the use of high-frequency acoustic cavitation and dairy products produced with its use. The research was carried out with the use of General scientific and special research methods in the laboratory of the Department of technology of storage and processing of animal products of the K. A. Timiryazev and in the accredited laboratory of technochemical control of the all-Russian research Institute of dairy industry. It is shown that the treatment of cow's milk-raw materials high-frequency ultrasonic vibrations (above 45 kHz), the generated electric ultrasonic device immersion type pulse impact ouzo "Activator-150", the number of bacteria of group of intestinal sticks (coliforms) decreased by almost 40%, which allows to make a conclusion about the appropriateness of the selected method of exposure for the destruction of microorganisms E. coli and coliform bacteria. Processed, using high-frequency acoustic cavitation, cow's milk was used for the production of brine cheese-cheese. It is shown that cheese cheese had a high nutritional value, which is due to the preservation of essential substances in the raw material (in particular, calcium, which in the production of cheese cheese precipitates if pasteurized milk is used), elastic consistency, safety of consumer characteristics - microbiological and physico-chemical.

scholarly journals A Review and Comparison of Solid, Multi-Strands and Litz Style PCB Winding

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1324
Author(s):  
Minh Huy Nguyen ◽  
Handy Fortin Blanchette
Keyword(s):  
High Frequency ◽  
Printed Circuit Board ◽  
Skin Resistance ◽  
Wide Frequency Range ◽  
Circuit Board ◽  
Frequency Range ◽  
Track Width ◽  
Printed Circuit ◽  
Pros And Cons ◽  
High Frequency Ac

At high frequency, AC resistance of a printed circuit board (PCB) winding becomes important and accounts for a large proportion of planar transformer losses. The winding is then influenced by both skin and proximity phenomenon, which makes the current distribution uneven resulting in an increased resistance. The study of improving AC resistance of a PCB winding has been tackled by many researchers. However, the lack of an overview and comparison among improvements has made it difficult to apply those methods to a specific winding. To overcome the above limitations, this paper investigates the pros and cons of three popular AC resistance optimizing methods: optimizing track width of a solid PCB winding, using multi-strands and using Litz style PCB winding. To verify the theoretical analysis, a total of 12 PCBs are simulated by finite element (FEM) and tested in the laboratory. Five criteria are analyzed, including skin resistance, proximity resistance, AC to DC ratio, total AC resistance and complexity are taken into consideration. The results of this study show that optimizing track width method has a significant improvement on AC resistance while the use of Litz PCB is effective for applications that need stable AC resistance in a wide frequency range. The use of parallel strands winding should be carefully considered as there is not significant benefit in both reducing the AC resistance and AC to DC ratio.

scholarly journals Studying the Influence of Acoustic Cavitation and Avalanche-Streamer Discharge on the Quality of Raw Milk in Order to Achieve the Pasteurization Effect

2020 ◽  
Author(s):  
Olga Krasulya ◽  
Kseniya Kanina ◽  
Nikolay Zhizhin ◽  
Nataliya Shlenskaya ◽  
Alexandra Demid
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Acoustic Cavitation ◽  
Raw Milk ◽  
Coliform Bacteria ◽  
Streamer Discharge ◽  
Anaerobic Microorganisms ◽  
Number Of Microorganisms ◽  
Quality Of Milk

The article presents the results of the studies obtained in the investigation of the quality of milk processed with the use of physical methods of exposure - acoustic cavitation and avalanche-streamer discharge, in order to achieve a pasteurizing effect. It is shown that in the treatment of high-frequency ultrasonic oscillations (over 45 kHz) generated by an electric ultrasonic device of the submersible type of impulse action ”Activator-150”, the number of bacteria of the E. coli group decreased by almost 40%, which allows concluding that the chosen method of influence is effective for the destruction of sanitary and pathogenic (indicative) microflora in raw milk and achieve a certain pasteurization effect. Using low-frequency ultrasonic exposure (20-22 kHz) generated by the cavitation ultrasonic flow type reactor RKU, the raw milk indicators QMAFAnM (Quantity of Mesophilic Aerobic and Facultative Anaerobic Microorganisms) and number of Coliform bacteria did not change after processing, as well as physical and chemical indicators, apart from the indicators of particle fineness. It can be stated that low-frequency ultrasonic cavitation treatment is not effective in terms of achieving a pasteurizing effect. In order to achieve a pasteurization effect by applying avalanche-streamer treatment we assessed its effect on QMAFAnM - the microbiological background of milk. The use of avalanche-streamer discharge does not have the expectation effect on the total number of microorganisms in milk. It is advisable to use high-frequency acoustic cavitation for microbial biota inactivation and avalanche-streamer discharge to reduce spore bacteria contamination.

scholarly journals Enhancement of high-frequency acoustic cavitation effects by a low-frequency stimulation

1997 ◽  
Vol 4 (3) ◽  
pp. 263-268 ◽  
Author(s):  
G. Iernetti ◽  
P. Ciuti ◽  
N.V. Dezhkunov ◽  
M. Reali ◽  
A. Francescutto ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Acoustic Cavitation ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation

Acoustic cavitation field prediction at low and high frequency ultrasounds

Ultrasonics ◽  
1998 ◽  
Vol 36 (1-5) ◽  
pp. 581-587 ◽  
Author(s):  
J.-L. Laborde ◽  
C. Bouyer ◽  
J.-P. Caltagirone ◽  
A. Gérard
Keyword(s):  
High Frequency ◽  
Acoustic Cavitation ◽  
Cavitation Field

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Sign in / Sign up

Export Citation Format

Share Document