Correctness Of Experimental Results Research Articles

Refraction of Oblique Shock Wave on a Tangential Discontinuity

The refraction of an oblique shock wave on a tangential discontinuity dividing two gas flows with different properties is considered. It is shown that its partial reflection occurs with the exception of the geometrical diffraction of an oblique shock. Another oblique shock, expansion wave or weak discontinuity that coincides with the Mach line can act as a reflected disturbance. This study focuses on the relationships that define the type of reflected discontinuity and its parameters. The domains of shock wave configurations with various types of reflected discontinuities, including characteristic refraction and refraction patterns with a reflected shock and a reflected rarefaction wave, are analyzed. The domains of existence of various shock wave structures with two types of reflected disturbance, and the boundaries between them, are defined. The domains of parameters with one or two solutions exist for the characteristic refraction. Each domain is mapped by the type of refraction with regard to the Mach number, the ratio of the specific heat capacities of the two flows and the intensity of a refracted oblique shock wave. The conditions of the regular refraction and the Mach refraction are formulated, and the boundaries between the two refraction types are defined for various types of gases. Refraction phenomena in various engineering problems (hydrocarbon gaseous fuel and its combustion products, diatomic gas, fuel mixture of oxygen and hydrogen, etc.) are discussed. The result can be applied to the modeling of the shock wave processes that occur in supersonic intakes and in rotating and stationary detonation engines. The solutions derived can be used by other researchers to check the quality of numerical methods and the correctness of experimental results.

The dyeing properties of natural cotton fabric

The cotton is one of representative natural fibres. By choosing the cotton fabric as the subject, this paper mainly discusses the impact of different dye quality, temperature of dye solution, dyeing time, bath ratio and salt quantity during the dyeing on the dye uptake and colour fastness, in order to find the optimal formula of dye solution. Samples are treated using the orthogonal experiment. Different levels of different factors are evenly divided into 25 groups. Results of each group are compared and analysed. According to the statistical analysis, it can confirm formula with the highest dye uptake and colour fastness. By balancing the amount of the both and considering the cost-saving as far as possible, it thus obtains the optimal formula. Finally, it proves the correctness of experimental results according to the comparison with the formula with the empirical parameters.

Mathematical methods for application of experimental adiabatic data – An update and extension

The paper represents some results of comparative analysis of the methods used for processing and interpreting data of adiabatic calorimetry as well as applying it to practical situations. Specifically two approaches are compared – approximate method based on evaluation of simplified kinetics and a more comprehensive, simulation-based method that utilizes the evaluation of more detailed kinetic models.The analysis is focused on two important types of data processing – correction of experimental results on thermal inertia (phi-factor correction) and estimation of adiabatic time to maximum rate (TMR).The most widely cited method for phi-factor correction is considered and its improvement is proposed to enable more precise prediction of the adiabatic time scale. A procedure for phi-factor correction of pressure response is also proposed. The limitations of this enhanced Fisher's method are discussed by comparison with simulation-based method. All the illustrative materials are based on real examples.As an example of application, the simplified method will be used to predict TMR and its limitations will be discussed.

An experimental indoor phasing system based on active optics using dispersed Hartmann sensing technology in the visible waveband

A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a smaller mirror, and so the larger version is always pursued by astronomers and astronomical technicians. Instead of using a monolithic primary mirror, more and more large telescopes, which are currently being planned or in construction, have adopted a segmented primary mirror design. Therefore, how to sense and phase such a primary mirror is a key issue for the future of extremely large optical/infrared telescopes. The Dispersed Fringe Sensor (DFS), or Dispersed Hartmann Sensor (DHS), is a non-contact method using broadband point light sources and it can estimate the piston by the two-directional spectrum formed by the transmissive grating's dispersion and lenslet array. Thus it can implement the combination of co-focusing by Shack-Hartmann technology and phasing by dispersed fringe sensing technologies such as the template-mapping method and the Hartmann method. We introduce the successful design, construction and alignment of our dispersed Hartmann sensor together with its design principles and simulations. We also conduct many successful real phasing tests and phasing corrections in the visible waveband using our existing indoor segmented mirror optics platform. Finally, some conclusions are reached based on the test and correction of experimental results.

Correction of experimental results in fission experiments: I. Dispersion corrections

The effect of mass and kinetic-energy dispersion on the results of fission experiments has been investigated. The effect is found to be small, except for the mass region close to symmetric fission.

Correction of experimental results in fission experiments: II. Neutron yield corrections

Various corrections have to be performed when the time-of-flight method is used, to determine the average number of neutrons emitted by fission fragments. These corrections enable one to determine the average number of neutrons in fission as a function of the fragment mass and total kinetic energy within the statistical errors, in most of the mass range.

Experimental Results on the Information Available from the Rise Time of Pulses Supplied by Semiconductor Particle Detectors

In this work it is experimentally shown that in several cases useful information about the impact angle or the mass of the particles can be obtained from the rise time of the pulses supplied by semiconductor detectors. Moreover a method is indicated of correction of experimental results which allows for a comparison with the previously obtained theoretical values. (cfr. Nucl. Inst. and Meth. 35 93 (1965). A method for digitalizing the information is also given.

A critical review on the thickness effect of birefringent coatings

In this paper, a reconsideration of the thickness effect of birefringent coating on the accuracy of the results obtained by this powerful experimental method was attempted. It was proved that thickness correction factorF, introduced by Duffy,1 is sensitive to higher harmonic terms of the functions in which the given displacement-distribution function is expanded. Correction of experimental results obtained with thick coatings and based on Duffy's correction method may lead to significant errors. However, this method remains very useful in predicting the proper thickness of the coating for a given strain distribution.

Effect on the Performance of a Small Air-Cooled Compression-Ignition Engine of Variations in the Ambient Atmospheric Conditions

In this paper consideration is given to the effect upon the performance of small compression-ignition engines of variations in ambient atmospheric conditions. The validity of some correction and derating formulae when applied to such engines is discussed, and an experimental investigation is described in which two small air-cooled compression-ignition engines were run at constant speed in atmospheric conditions which could be controlled at values ranging from the normal to those widely different from normal conditions. Some conclusions relating to corrections for deviation from standard conditions are drawn from these test results and a comparison is given of the correction of experimental results by a number of correction or derating formulae, which are described in Appendix I