scholarly journals Two 27 MHz Simple Inductive Loops, as Hyperthermia Treatment Applicators: Theoretical Analysis and Development

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Vassilis Kouloulias ◽  
Irene Karanasiou ◽  
Maria Koutsoupidou ◽  
George Matsopoulos ◽  
John Kouvaris ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Tumor Formation ◽  
Function Technique ◽  
Hyperthermia Treatment ◽  
Simple Loop ◽  
Theoretical Simulation ◽  
Inductive Loop ◽  
Loop Antennas ◽  
Spherical Tumor

Background. Deep heating is still the main subject for research in hyperthermia treatment.Aim. The purpose of this study was to develop and analyze a simple loop as a heating applicator.Methods. The performance of two 27 MHz inductive loop antennas as potential applicators in hyperthermia treatment was studied theoretically as well as experimentally in phantoms. Two inductive loop antennas with radii 7 cm and 9 cm were designed, simulated, and constructed. The theoretical analysis was performed by using Green’s function and Bessel’s function technique. Experiments were performed with phantoms radiated by the aforementioned loop antennas.Results. The specific absorption rate (SAR) distributions were estimated from the respective local phantom temperature measurements. Comparisons of the theoretical, simulation, and experimental studies showed satisfying agreement. The penetration depth was measured theoretically and experimentally in the range of 2–3.5 cm.Conclusion. The theoretical and experimental analysis showed that current loops are efficient in the case where the peripheral heating of spherical tumor formation located at 2–3.5 cm depth is required.

scholarly journals Theoretical and experimental studies of a gas stamping device with a piston pressure multiplier

2019 ◽  
Vol 18 (1) ◽  
pp. 163-173
Author(s):  
A. Yu. Botashev ◽  
R. A. Bayramukov
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Fuel Mixture ◽  
Small Scale ◽  
Scale Production ◽  
Pressure Treatment ◽  
Energy Of Combustion ◽  
Stamping Process ◽  
Pressure Multiplier ◽  
The Matrix

In many industries, the share of small-scale production plants is significant. In these conditions, compared with traditional methods of pressure treatment, pulse pressure treatment methods, one of the varieties of which is gas stamping, are more efficient. However, the known devices of gas stamping provide mainly stamping of thin-walled parts. To expand the technological capabilities of gas stamping, the authors developed a gas stamping device with a piston pressure multiplier, in which heating and deformation of the stamping workpiece is carried out using the energy of combustion of fuel mixtures in the combustion chamber, in the working cylinder and in the cavity of the matrix. This article is devoted to the study of the workflow of this device. Theoretical analysis of the workflow was carried out, and, as a result, a pattern was determined for the variation of the pressure that performs the stamping process in the working cylinder. In particular, it was found that at the final stage of the stamping process, due to the energy of combustion of the fuel mixture, the pressure in the working cylinder increases 1.5...2 times, which allows a significant increase in the thickness of the parts to be stamped. An experimental gas stamping device with a piston pressure multiplier was developed, and experimental studies were carried out. The studies confirmed the main results of the theoretical analysis: the discrepancy between the theoretical and experimental values of the degree of pressure multiplication in the working cylinder does not exceed 11%.

Experimental Study and Analysis of Different Air-Injecting Segment on the Separation Performance of Air-Injected De-Oiling Hydrocyclone

2008 ◽  
Author(s):  
Minghu Jiang ◽  
Dehai Chen ◽  
Lixin Zhao ◽  
Liying Sun
Keyword(s):  
Experimental Study ◽  
Theoretical Analysis ◽  
Separation Efficiency ◽  
State Of The Art ◽  
Experimental Studies ◽  
Separation Performance ◽  
Research Results ◽  
Compound Body ◽  
Oil Gas

Developing state-of-the-art and separating principle of deoiling hydrocyclones are introduced. By theoretical analysis, the ways to enhance hydrocyclone’s separation efficiency are described. One way is to inject air into the hydrocyclones so as to combine with oil to form oil-gas compound body, and then increase de-oiling efficiency. By means of injecting air into large cone segment, or fine cone segment of the hydrocyclone, experiments were carried out. It is found that the best injecting part is fine cone segment. Further experimental studies were continued for confirming detail part in fine cone segment, which includes one-third segment and two-thirds segment for the sake of research. Results show that the best air-injecting part is the first one-third segment of fine cone segment. This conclusion would be useful for understanding of air-injected de-oiling hydrocyclone’s separating process, and for its design and applications.

scholarly journals Modeling of structuring processes at hardening of expanding cements and concretes on their basis

2018 ◽  
Vol 196 ◽  
pp. 04035 ◽  
Author(s):  
Igor Kharchenko ◽  
Alexander Panchenko ◽  
Alexey Kharchenko ◽  
Vyacheslav Alekseev
Keyword(s):  
Theoretical Analysis ◽  
Rheological Model ◽  
Experimental Studies ◽  
High Strength ◽  
Cementitious Materials ◽  
Cement Stone ◽  
Formation Processes ◽  
Structure And Properties ◽  
Potential Index ◽  
Kinetics Of

This paper reports the results of experimental research of the effect of strain-restriction conditions on the structure and properties of sulfoaluminate expanding cementitious materials. Theoretical analysis of the development of pattern formation processes is performed by applying the developed rheological model, illustrating features of the kinetics of structure-forming processes according to the ratio of the potential index of extension with linear, flat and volumetric limitation of deformations of the extension. The results show that rheological model adequately correlates with the results of experimental studies and can be described mathematically. Found that with the volume limitation of deformations arising when mixing crystallographic phases with high density and strength, the pore structure of the cement stone contains mainly gel pores. This is the main prerequisite for obtaining a dense, high-strength and durable structure of cement stone and concrete on its basis.

ANALYSIS OF THE STATE OF INSULATION OF ELECTRICAL EQUIPMENT OF MINING AND METALLURGICAL COMPANIES

2020 ◽  
Vol 2 (1) ◽  
pp. 201-215
Author(s):  
R.V. KLYUEV ◽  
◽  
I.I. BOSIKOV ◽  
O.A. GAVRINA ◽  
K.S. KRYSANOV ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
High Altitude ◽  
Experimental Studies ◽  
Electrical Equipment ◽  
Insulation Resistance ◽  
Air Humidity ◽  
Electric Networks ◽  
Single Method ◽  
Underground Workings ◽  
Mathematical Processing

The paper presents the results of theoretical analysis and mathematical processing of experimental studies of the insulation state of individual elements of the same type of sections of 0.4 kV electric networks in underground workings conducted at the mining and processing mines at heights of workings up to 1000 m above sea level. The studies were carried out according to a single method in order to identify the effect of highlands on the insulation state of individual elements of 0.4 kV networks. It is recommended to complete scraper winches, fans and other mechanisms of high-altitude mines with organosilicon-insulated engines or with front coatings filled with top coat varnishes similar to excavator engines. A similar situation is noted with the launcher. More than 50 % of all the equipment of high-altitude mines have an active insulation resistance of less than 20 mOhm. A higher asymmetry of the total and active insulation resistance of launchers is noted. It is recommended to use silica gel to reduce air humidity inside the shells of the launcher...

scholarly journals Role of microRNA Shuttled in Small Extracellular Vesicles Derived From Mesenchymal Stem/Stromal Cells for Osteoarticular Disease Treatment

2021 ◽  
Vol 12 ◽  
Author(s):  
Eliana Lara-Barba ◽  
María Jesús Araya ◽  
Charlotte Nicole Hill ◽  
Felipe A. Bustamante-Barrientos ◽  
Alexander Ortloff ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Stromal Cells ◽  
Gene Expression Regulation ◽  
Biological Effects ◽  
Experimental Studies ◽  
Tumor Formation ◽  
Target Cells ◽  
Therapeutic Effects ◽  
Age Related ◽  
Current Therapies

Osteoarticular diseases (OD), such as rheumatoid arthritis (RA) and osteoarthritis (OA) are chronic autoimmune/inflammatory and age-related diseases that affect the joints and other organs for which the current therapies are not effective. Cell therapy using mesenchymal stem/stromal cells (MSCs) is an alternative treatment due to their immunomodulatory and tissue differentiation capacity. Several experimental studies in numerous diseases have demonstrated the MSCs’ therapeutic effects. However, MSCs have shown heterogeneity, instability of stemness and differentiation capacities, limited homing ability, and various adverse responses such as abnormal differentiation and tumor formation. Recently, acellular therapy based on MSC secreted factors has raised the attention of several studies. It has been shown that molecules embedded in extracellular vesicles (EVs) derived from MSCs, particularly those from the small fraction enriched in exosomes (sEVs), effectively mimic their impact in target cells. The biological effects of sEVs critically depend on their cargo, where sEVs-embedded microRNAs (miRNAs) are particularly relevant due to their crucial role in gene expression regulation. Therefore, in this review, we will focus on the effect of sEVs derived from MSCs and their miRNA cargo on target cells associated with the pathology of RA and OA and their potential therapeutic impact.

Thermal Conductivity of Si/SiGe Superlattice Film

2008 ◽  
Author(s):  
Chun-Kai Liu ◽  
Heng-Chieh Chien ◽  
Ming-Ji Dai ◽  
Chih-Kuang Yu ◽  
Chun-Yeh Hsu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Theoretical Analysis ◽  
High Vacuum ◽  
Experimental Studies ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Interfacial Thermal Resistance ◽  
Boltzmann Transport ◽  
Superlattice Structure ◽  
Acoustic Mismatch

It has been proposed that the use of superlattice structure is effective for reduction of lattice thermal conductivity in the direction perpendicular to superlattice interfaces which can lead to improvement of figure of merit. In this work, we have evaluated the thermal conductivity of Si/SiGe superlattice structure films by theoretical analysis and experimental studies. In experiments, the ultra-high vacuum chemical vapor deposition (UHVCVD) has been employed to formation the Si/Si0.71Ge0.29 superlattice film. The cross-plane thermal conductivity of a Si/Si0.71Ge0.29 superlattice is measured based on the 3 ω method. In theoretical analysis, we use the Boltzmann transport equation to analyze the phenon transport in superlattice film. We compared the thermal conductivities of several Si/Si0.71Ge0.29 superlattice structure films by changing the thickness of Si and Si0.71Ge0.29. The results indicate that increasing the period (one layer Si and one layer Si0.71Ge0.29) length will lead to increase acoustic mismatch between the adjacent layers, and hence increased interfacial thermal resistance. However, if the total thickness of the superlattice film is fixed, reducing the period length will lead to decreased effective thermal conductivity due to the increased number of interfaces.

Temperature and Humidity Effects on Micro/Nano Handling

2006 ◽  
Vol 532-533 ◽  
pp. 681-684 ◽  
Author(s):  
Quan Zhou ◽  
Bo Chang ◽  
Heikki N. Koivo
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Enabling Technology ◽  
Severe Problem ◽  
Scale Adhesion ◽  
Humidity Effects ◽  
Micro Scale ◽  
Environment Temperature ◽  
Temperature And Humidity ◽  
Environment Parameters

Micro/nano handling is an important enabling technology for future manufacturing. In the micro scale, adhesion is a severe problem for efficient and accurate handling tasks. The cause of the adhesion is largely from the microforces, namely van der Waals, electrostatic and capillary forces. Those forces, however, are functions of ambient environmental conditions. This paper exams two important ambient environment parameters in normal micro/nano handling environment: temperature and humidity, in both theoretical analysis and experimental studies. A short guideline for microhandling with temperature and humidity consideration is suggested based on the studies.

EXPERIMENTAL STUDIES ON THE NOISE AND VIBRATION OF A SPECIAL BORING MACHINE DUE TO FORMATION OF THE OPERATOR´S WORKPLACE SOUND FIELD

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 100-103
Author(s):  
Alexander Shashurin ◽  
Marat Goguadze ◽  
Anna Lubianchenko
Keyword(s):  
Theoretical Analysis ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Sound Radiation ◽  
Sound Field ◽  
Noise Levels ◽  
Noise And Vibration ◽  
Measurement Results ◽  
Sound Pressure Levels ◽  
Excessive Noise

The purpose of this study is to measure the octave sound pressure levels and vibrations of a boring machine. A theoretical analysis of the sound pressure levels near the boring machine is performed. The measurement results are given. It was found that the workplace sound pressure levels exceed the sanitary standards, which suggests that the excessive noise levels are due to the exposure to the cutter sound radiation and the axis being machined.

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