Experimental Study of the Superconducting Microstrip Antenna as a Protective Device of the Receiver From Electromagnetic Damage

The paper presents the results of experimental studies of a superconducting protective antenna, which consists of a high-temperature film deposited by a magnetron or a laser beam on a substrate. The work is carried out:- analysis of the selection criteria for the substrate type (Al2O3, Y2O3, SrTiO3, MgO) and the method for depositing a high-temperature superconducting film (HTSF) on its surface – YBaCuO- analysis of the methods of making contacts, which allow to reduce losses when passing a signal from the superconducting microstrip antenna to the waveguide path.The aim of this article is determination of the parameters of a prototype sample of a microstrip antenna device made from HTSF: transient characteristics of high-temperature superconductors, HTSF impulsive characteristics, recovery time of the superconducting state after the action of a powerful pulse on the protective device, the amplitude-frequency characteristics of the protective device in the superconducting state. This will allow to evaluate the possibility of using a microstrip antenna device made from high-temperature superconductors to protect the receiving systems from electromagnetic damage. The absence of a unified theory of high-temperature superconductivity leads to the need to select an analytical form of the functions of the amplitude-frequency characteristics of superconducting protection, and for this mathematical models are used in the programs "APPROX", "MathCAD14.0". The reliability of the obtained results of mathematical modeling of the processes of protection and recovery of the superconducting state after electromagnetic shock are confirmed in the course of experimental studies (an error of 0.15%)

Analytical and Experimental Study Bamboo Beam Concrete

This study is known as the Bamboo Concrete Beams (B3) with bamboo casing as an alternative reinforcement, conducted through experimental methods. The test results were then verified through analytical calculations. Behaviors examined included mechanical properties of bending, beam flexural strength and fracture patterns are burdened by the quasi-static load. Researchers used 16 pieces of the test specimen. Bamboo specimens used in this study is a type of Petung Bamboo (Dendrocalamus Asper), with a long piece of bamboo varies from 2860 mm to 3910 mm, outer diameter of the bottom of the 105 mm to 155 mm and the outer diameter of the upper section of 95 mm to 135 mm, which are grouped into 5 kinds of testing that is,1. Bamboo intact, the inner segments remain, with BA code (2 pieces of the specimen)2. Bamboo intact, the inner segments removed, the code BP (2 pieces of the specimen)3. Bamboo shoots in a section removed (like bamboo pipes) and not given a bamboo rod stud, with code BTS (4 pieces of the test specimen).4. Bamboo shoots in a section removed (like bamboo pipes) and given a bamboo rod stud on the inside along ½ bamboo inner diameter, with code BAS (4 pieces of the test specimen). 5. One side of the split bamboo rod sections with a thickness of 75 mm, inner bamboo segments remain (such as drums) and given a bamboo rod stud on the inside, with code KTGN (4 pieces of the test specimen). Value of the maximum load Pmax, the maximum moment Mmax and ï´max deflection for each specimen according to the results of observation and calculation is as follow

Experimental Study of Quenching Process During Bottom Reflooding Using “Queen” Test Section

Phenomenon of quenching of hot fuels in core during bottom reflooding following loca event is investigated in order to understand the performance cooling process. the study is conducted experimentally using queen test section which allow study of rod surface temperature histories based on which the heat fluxes are estimated. the visual observation is also done to study the boiling regimes. the test variables are initial rod temperature, i.e. 400oc, 500oc and 600oc, and coolant flow rate, i.e. 0,01kg/s, 0.02 kg/s and 0.04 kg/s with constant water inlet temperature of 30oc. the results shows different heat transfer regimes such as film boiling, transition boiling, nucleate boiling and convective single phase heat transfer regimes. for specified initial rod temperature, the higher flow rate provides high rewet velocity and higher maximum heat flux, then quenching process is more effective

An experimental study of the investment implications of bankruptcy laws

In bankruptcy laws, proportionality is the universal norm when allocating the liquidation value of a bankrupt firm among creditors. The theoretical literature on bankruptcy proposes two prominent alternatives to proportionality: the equal awards and the equal losses principles. We use an experiment to analyze and compare actual creditor behavior under these three principles. More specifically, we test the following hypotheses: replacing proportionality with equal losses increases total investment while replacing proportionality with equal awards decreases total investment; under all three principles individual investment choices decrease in response to an increase in the probability of bankruptcy or an increase in risk aversion; total investment difference between proportionality and either of the other two principles is independent of the probability of bankruptcy as long as both induce an interior equilibrium. The results of the nonparametric tests and random effects Tobit regression analyses we conduct on our experimental data offer support for all hypotheses

Numerical and experimental study of the impact of temperature on relative permeability in an oil and water system.

Relative permeability is affected by several flow parameters, predominantly operating temperature and fluid viscosity. Fluid viscosity changes with temperature, which correspondingly affects the relative permeability. Temperature is believed to have a considerable effect on oil–water relative permeability and thus is a vital input parameter in petroleum reservoir development modelling. The actual effect of temperature on oil–water relative permeability curves has been a subject of debate within the scientific community. This is based on contradictory experimental and numerical results concerning the effect of temperature on oil–water relative permeability in literature. This study investigates the effect of temperature on multiphase flow physics in a porous media under varying temperature conditions. A computational fluid dynamics approach was adopted for a pore-scale study of the temperature effect on oil recovery factor under a water- and oil-wet condition. For the oil–water relative permeability investigation, a series of coreflooding experiments were conducted with well-sorted unconsolidated silica sandpacks, adopting the unsteady-state relative permeability method. The series of experiments were performed at different temperatures (range between 40 to 80 °C). Three levels of injection flowrates (0.5, 0.75 and 1.0 mL/min) and two oil viscosities (43 cP motor and 21 cP mineral oil – at 60 oC) were used in the study. A history matching approach using the commercial software Sendra was used to determine the oil-water relative permeability for each respective temperature, flowrate and oil viscosity. A support vector regression algorithm was later implemented for the machine learning modelling aspect of this work, which can predict reliable temperature dependent oil–water relative permeability. The pore-scale results showed that the displacement behaviour of water and oil-wet system is strongly affected by the contact angle with a profound effect on the oil recovery factor. The water-wet system resulted in about 35 – 45 % more oil recovery than the oil-wet system, with the unrecovered oil mainly adhering to the wall region of the pore bodies of the oil–water system. The results from all the experimental cases showed that the oil–water relative permeability is a function of temperature, water injection flowrate and oil viscosity. In addition, the experimental findings show a decreasing residual oil saturation of the more viscous fluid with increasing injection flowrate. The end-point water relative permeability varies slightly for the set of experiments, with the values higher for the less viscous oil under the same flowrate condition. Generally, the profile of oil and water relative permeability curve changes with varying oil viscosity and water injection flowrate at the same operating condition. This behaviour shows that the viscosity of oil is an important factor to be considered when selecting displacement flowrate to guarantee high oil production. Furthermore, an increment in temperature results in a corresponding rise in the relative permeability of both oil and water. Comparison of the experimental and machine learning results showed a good match, with consistency across all datasets. In addition to the machine learning model, this study proposes a modified empirical model using nonlinear least square regression for application in unconsolidated porous media. The output from this model can be applied for relative permeability prediction, preliminary evaluation in experimental design and as a valuable benchmarking tool for future laboratory experiments under varying temperature conditions

Experimental Study of an Aluminum-Polysilicon Thermopile for Implementation of Airflow Sensor on Silicon Chip

A multi-directional airflow sensor has been realized. The essential part of the considered sensor is a thermopile configuration, which enables the measurement of flow speed and flow direction. The thermopile is a series arrangement of eight thermocouples. A thermocouple converts a difference in temperature into an electrical signal, by means of the Seebeck effect . The thermocouples are made of aluminum-N-type polysilicon junctions. The incoming flow is heated and the degree of heat transfer by convection to the flow, depends on the speed of the flow; the faster the flow the smaller the heat transfer, which leads to a smaller (Seebeck) output voltage of the thermopiles. After signal conditioning - i.e., filtering and amplification by means of an amplification system - the electrical output signals of the thermopiles are further signal-processed by applying analog-to-digital signal conversion, so that finally the flow speed and the flow direction can be properly displayed on a computer screen. The measured values of the Seebeck coefficient or thermopower (S) were in the range of: 0.43 to 0.68 mV/K which are in good agreement with the values found in the literature: 0.5 to 0.7 mV/K. Moreover, it was found that the flow speed U is proportional to the reciprocal value of the square of the output voltage of the outgoing thermopile