5,214,013 research outputs found

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

    Get PDF
    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%)

    Experimental Parametric Study of Biodiesel to Develop Economic Zero Effluent Discharge (ZED) for Diesel System

    Full text link
    In this globalization realm, there in constant growth in the rate of expenditure of fossil fuels, consequent on ever increasing population and urbanization. This gives charge to depletion of finite resources in the near future. Fossil fuel emission causes global-warming also green-house gases are intangible factor which collectively degrading the planet. As such, the situation demands for an alternate source of energy that can be used to overcome the conjectured energy crisis. In contrast to this, if the energy source is clean and renewable, it will reduce the environmental trouble as well. In the quest an alternate and renewable energy resources, scientists have plead with a variety of options among which biodiesel-diesel blends as alternative fuels has become a popular option and is getting the attention of many researchers. This is because scientists have enlist the properties of biodiesel prepared from vegetable oils are very close to commercial diesel and thus it has a promising future as an alternative fuel for diesel engine. Biodiesel being renewable, biodegradable and green fuel can reduce our dependence on conventional/non-renewable fossil fuels and it also helps to keep pure quality of air by reducing obnoxious automotive/vehicular emissions. Possible solution of this problem is to replace or find renewable and economically feasible fuel as an alternative source. Already a lot of work for source which fulfill the criteria of sustainability and economical carried out. But the effluent is critical issues. So characterization and formation of biodiesel with zero effluent is prime objective

    Analytical and Experimental Study Bamboo Beam Concrete

    Full text link
    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

    Full text link
    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

    Get PDF
    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

    Experimental study of premixed gasoline surrogates burning velocities in a spherical combustion bomb at engine like conditions

    Get PDF
    Producción CientíficaIn this work are presented experimental values of the burning velocity of iso-octane/air, n-heptane/air and n-heptane/toluene/air mixtures, gasoline surrogates valid over a range of pressures and temperatures similar to those obtained in internal combustion engines. The present work is based on a method to determine the burning velocities of liquid fuels in a spherical constant volume combustion bomb, in which the initial conditions of pressure, temperature and fuel/air equivalence ratios can be accurately established. A two-zone thermodynamic diagnostic model was used to analyze the combustion pressure trace and calculate thermodynamic variables that cannot be directly measured: the burning velocity and mass burning rate. This experimental facility has been used and validated before for the determination of the burning velocity of gaseous fuels and it is validated in this work for liquid fuels. The values obtained for the burning velocity are expressed as power laws of the pressure, temperature and equivalence ratio. Iso-octane, n-heptane and mixtures of n-heptane/toluene have been used as surrogates, with toluene accounting for the aromatic part of the fuel. Initially, the method is validated for liquid fuels by determining the burning velocity of iso-octane and then comparing the results with those corresponding in the literature. Following, the burning velocity of n-heptane and a blend of 50% n-heptane and 50% toluene are determined. Results of the burning velocities of iso-octane have been obtained for pressures between 0.1 and 0.5 MPa and temperatures between 360 and 450 K, for n-heptane 0.1–1.2 MPa and 370–650 K, and for the mixture of 50% n-heptane/50% toluene 0.2–1.0 MPa and 360–700 K. The power law correlations obtained with the results for the three different fuels show a positive dependence with the initial temperature and the equivalence ratio, and an inverse dependence with the initial pressure. Finally, the comparison of the burning velocity results of iso-octane and n-heptane with those obtained in the literature show a good agreement, validating the method used. Analytical expressions of burning velocity as power laws of pressure and unburned temperature are presented for each fuel and equivalence ratio.Ministerio de Ciencia e Innovación (PID2019-106957RB-C22