scholarly journals The ignition of solid explosive media by hot wires

1949 ◽  
Vol 198 (1055) ◽  
pp. 523-539 ◽  
Keyword(s):  
Energy Equation ◽  
Critical Factor ◽  
Heat Losses ◽  
Heating Element ◽  
Heating Process ◽  
Physical Factors ◽  
Ignition Process ◽  
Chemical Action ◽  
Ignition System ◽  
The Moment

The present paper describes an investigation of the physical factors affecting the ignition of solid explosives by heated filaments embedded in the medium. The filaments were composed of fine resistance wire and were heated electrically, the critical thermal energy required to cause ignition being measured for wires of different geometrical, thermal and electrical characteristics and for different times of heating. Systematic variation of these factors enabled the energy equation for the ignition process to be formulated and its terms analyzed, the technique involving extrapolation to zero time of heating as a means of eliminating heat losses from the ignition system, and extrapolation to zero diameter of wire in order to eliminate terms involving the heating element; the former simulates the ideal case of a heat-insulated ignition system and the latter that of a line source of heat. The energy equation for ignition in these circumstances takes a simple form which implies that, at the moment of ignition, the heat supplied to the ignition system always equals the heat gained by the system plus the heat lost, the absence of any term representing heat generated by chemical action being very significant. For a given ignition system, the amount of heat absorbed up to the moment of ignition is shown to be independent of time, so that the increase in ignition energy with increasing time of ignition is wholly attributable to the heat losses sustained by the ignition system during the heating process. Further analysis shows that the critical factor governing ignition in systems of the type considered is the temperature, and that the geometry of the heating element probably determines the amount of explosive which must be raised to the critical temperature to ensure ignition.

Numerical and Experimental Analysis of Ignition and Combustion Stability in EGR Dilute GDI Operation

2014 ◽  
Author(s):  
Riccardo Scarcelli ◽  
Nicholas S. Matthias ◽  
Thomas Wallner
Keyword(s):  
Flame Propagation ◽  
Numerical Results ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Ignition Process ◽  
Ignition System ◽  
Cyclic Variability ◽  
Beneficial Effects ◽  
Engine Testing ◽  
Ignition And Combustion

This paper discusses the characteristics of EGR dilute GDI engines in terms of combustion stability. A combined approach consisting of RANS numerical simulations integrated with experimental engine testing is used to analyze the effect of the ignition source on flame propagation under dilute operating conditions. A programmable spark-based ignition system is compared to a production spark system in terms of cyclic variability and ultimately indicated efficiency. 3D-CFD simulations are carried out for multiple cycles with the goal of establishing correlations between the characteristics of the ignition system and flame propagation as well as cycle-to-cycle variations. Numerical results are compared to engine data in terms of in-cylinder pressure traces. The results show that an improved control over the energy released to the fluid surrounding the spark domain during the ignition process has beneficial effects on combustion stability. This allows extending the dilution tolerance for fuel/air mixtures. Although affected by cyclic variability, numerical results show good qualitative agreement with experimental data. The result is a simple but promising approach for relatively quick assessment of stability improvements from advanced and alternative ignition strategies.

scholarly journals On the condition of certain elements at the moment of chemical change

1851 ◽  
Vol 5 ◽  
pp. 967-968
Keyword(s):  
Chemical Nature ◽  
Chemical Change ◽  
Chemical Action ◽  
Chemical Substances ◽  
Negative Relation ◽  
True Type ◽  
The Moment ◽  
Double Decomposition ◽  
Theoretical Considerations

This paper contains an experimental inquiry, founded upon certain theoretical considerations as to the condition of bodies at the moment of chemical change, with the discussion of which the introduction is occupied. The author considers that the peculiar combining properties of the elemental particles of which chemical substances are composed, are due to a chemical polarity of the acting masses, which takes place at the contact of the bodies, and have only a remote relation to the electro-chemical nature of the isolated element. In support of this view are cited the phenomena of double decomposition, and the properties of the so-called “nascent” elements, which could never be inferred from the nature of the element when once isolated and formed. Double decomposition the author considers to be the true type of all chemical action. In the case of the bodies called compound, this polarity is manifested by the division of the substance into two parts, which are universally considered to stand to one another in a certain positive and negative relation; and also by the synthesis, which corresponds to this division.

scholarly journals Effect of Experimental Conditions on 7075 Aluminium Response during Thixoextrusion

2012 ◽  
Vol 504-506 ◽  
pp. 345-350 ◽  
Author(s):  
Adriana Neag ◽  
Véronique Favier ◽  
Mariana Pop ◽  
Eric Becker ◽  
Régis Bigot
Keyword(s):  
Aluminum Alloy ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Liquid Fraction ◽  
Heat Losses ◽  
Heating Process ◽  
Semisolid State ◽  
Experimental Conditions ◽  
Solid Aluminum ◽  
Semi Solid

The deformation behavior of semi-solid aluminum alloy is strongly dependent on the microstructure. This paper illustrates several experimental research works concerning thixoextrusion of 7075 aluminum alloy which was carried out at “Arts et Métiers ParisTech” of Metz. Inductive re-heating of the aluminum billet is the method used in order to obtain the target liquid fraction for thixoextrusion. To minimize the heat losses, a sample obtained from a direct extruded bar is inserted in a die for reheating in semisolid state and thixoextrusion. During the experimental re-heating process, the temperature was directly controlled by using thermocouples for temperature measurements in the sample and also in the die. The influence of different working ram speeds and reheating temperature on the microstructure evolution was studied by optical microscopy. The experimental results on extrusion load and microstructure evolution of the component are reported.

Evaluation of the Cover Glasses in Solar Cookers Box-Type Considering Conduction Heat Losses in Four Different Solar Cookers

2016 ◽  
Author(s):  
Hilario Terres ◽  
Sandra Chavez ◽  
Raymundo Lopez ◽  
Arturo Lizardi ◽  
Araceli Lara
Keyword(s):  
Solar Radiation ◽  
Heat Loss ◽  
Experimental Tests ◽  
Heat Losses ◽  
Cooking Time ◽  
Heating Process ◽  
Labview Software ◽  
Radiation Losses ◽  
Compact Field

A evaluation of the conduction heat loss over their cover for four different solar cookers box-type (1. Square solar cooker with inner reflectors placed in right angles, 2. Square solar cooker with inner reflector placed in different angles, 3. Rectangular solar cooker with inner reflectors placed in different angles and 4. Octagonal solar cooker with inner reflectors placed in right angles) is presented. In the heating process in a solar cooker box-type, the conduction heat loss in their cover is the most important in comparative with convection and radiation losses. The cover in solar cookers is made with clear glasses, which allows the inlet solar radiation inside of it. When the heating process happen, the temperature in the cover glasses is important and is important for this part. To evaluate the magnitude for the heat loss, controlled tests were planned, where a solar radiation simulator was used as energy source over the solar cookers considered. In the experiments, thermocouples to determine the gradient temperature for thickness among glasses were placed. In this activity, a Compact Field and LabView software were used. Also, in the experimental tests, thermographic imagines for some instants during the heating process were taken. According results, the conduction heat losses are bigger than 25 % of the inlet energy Flux in the cookers. The biggest values for temperature on the glasses correspond to the solar cooker 3, while minimum values are obtained for the solar cooker 1. The solar cooker 1 present the biggest conduction heat losses and the cooker 4, has the minimum values for the losses. Results of this work can be useful and important for design proposes which could impacts on save of money and cooking time.

scholarly journals 731 PB 501 INTERGRATING MICROWAVE FOOD PROCESSING INTO PLANTAIN UTILIZATION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 537f-537
Author(s):  
O. Smith-Kayode
Keyword(s):  
Service Industry ◽  
Food Service ◽  
Spherical Shape ◽  
Food Product ◽  
Developed Countries ◽  
Heating Process ◽  
Physical Factors ◽  
Menu Item ◽  
Quality Product ◽  
The Tropics

Plantain (Musa parasidiaca), a staple among estimated 70 million Africans and popular item in the tropics is emerging as specialty ethnic food product in developed countries. It is suitable as menu item for food service particularly in the ripe form when deep oil fried. The perishability of the fruit is a major constraint to wide spread use and distribution. To expand the utilization base in the food service industry, microwave heating process was applied to tempering and cooking of frozen pre-fried slices. The purpose of this is to determine the effect of the process on warmed over properties and acceptability of fried plantain. Large surface area and spherical shape were critical physical factors in the heating thus providing good quality product from taste, texture and appearance standpoint

scholarly journals Investigation of the Causes of Violations of the Radioactive Balance between Radionuclides of the Uranium Decay Chain

2021 ◽  
Vol 8 (7) ◽  
pp. 95
Author(s):  
Soliyev T.I. ◽  
Muzafarov A.M.
Keyword(s):  
Daughter Nucleus ◽  
Theoretical Calculations ◽  
Technological Factor ◽  
Critical Factor ◽  
Decay Chain ◽  
Recoil Energy ◽  
Physical Factors ◽  
Underground Leaching ◽  
Radioactive Equilibrium ◽  
Nuclear Masses

Throughout the literature, it is mentioned that 15 radionuclides in the uranium decay chain have a constant radioactive equilibrium. Theoretical calculations give the value of the activity of each radionuclide in the uranium decay chain.This article examines various factors that affect the coefficient of radioactive equilibrium between radionuclides in the uranium decay chainThe concept of the coefficient of violations of nuclear equilibrium between radionuclides is adopted to determine the degree of violations in the uranium decay chain.Many nuclear-physical factors influence the radioactive balance between radionuclides. The most important of them is the recoil energy that the daughter nucleus receives when splitting from the mother nucleus.Another critical factor in the violation of the radioactive balance between radionuclides is the technological factor: leaching (acid, mini-reagent, bicarbonate, etc.) when leaching uranium by underground leaching of uranium.In addition, as a theoretical result of the study, the article presents a graphical relationship between the number of nuclear masses and the recoil energy of radionuclides in the uranium decay chain.

scholarly journals Hot spot heating process estimate using a laser-accelerated quasi-Maxwellian deuteron beam

2011 ◽  
Vol 30 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Xiaoling Yang ◽  
George H. Miley ◽  
Kirk A. Flippo ◽  
Heinrich Hora
Keyword(s):  
Beam Energy ◽  
Short Pulse ◽  
Hot Spot ◽  
Ion Beam ◽  
Deuteron Beam ◽  
Heating Process ◽  
Energy Calculation ◽  
Ignition Process ◽  
Beam Focusing ◽  
Proton Beam Energy

AbstractThe hot spot heating process by an assumed deuteron beam is evaluated in order to estimate the contribution of the energy produced by the deuteron beam-target fusion to the heating process. The deuteron beam energy versus the number of deuterons is evaluated through the experimentally achieved proton beam energy distribution using the TRIDENT short pulse laser at the Los Alamos National Laboratory (LANL). The corresponding hot spot heating is then calculated using this assumed deuteron beam spectrum. The resulting first order heating dynamics is employed in the expanded “bonus” energy calculation, and a 12.73% extra energy from deuteron beam-target fusion was found with the assumed deuteron spectrum when ρrb = 4.5 g/cm2 is considered, where ρ is the fuel density, and rb is the ion beam focusing radius on the target. The results provide further insight into the contribution of the extra heat produced by deuteron beam-target fusion to the hot spot ignition process. A further analysis of how a converter foil using ultra-high-density cluster materials can help to achieve the yield requirements for ignition is presented.

scholarly journals The integration of information systems in a medical facility to improve the efficiency of decision-making

2020 ◽  
Vol 224 ◽  
pp. 03029
Author(s):  
Marina Bolsunovskaya ◽  
Alexander Leksashov ◽  
Aleksey Gintciak ◽  
Anastasiia Shirokova
Keyword(s):  
Decision Making ◽  
Information System ◽  
Critical Factor ◽  
Final Diagnosis ◽  
Operational Planning ◽  
Quality Of Services ◽  
Medical Facility ◽  
System A ◽  
The Moment

This paper describes a project for integrating a medical and diagnostic information system in a medical facility. At the moment, making effective and timely decisions in diagnosis and treatment is most important. Integration of systems has significantly improved the efficiency of decision-making by updating data. The unified information space allowed to increase the objectivity of diagnostics and increase the reliability of the information system. A critical factor in making a decision is the stage at which the disease is detected, as well as a description of what types of medical care are important for analysis. In addition, the need to synchronize on the basis of the detailed information for operational planning and routing of patients. Integration of solutions will increase the speed of passing examinations and the speed of making a final diagnosis. Thanks to the implemented solution, it became possible to increase the speed and improve the quality of services provided. The ability to synchronize activity planning based on effective diagnostics is essential.

Development of a New Finite-Element Method to Analyze Deformation of Plate Due to Line Heating

2001 ◽  
Vol 17 (01) ◽  
pp. 1-7
Author(s):  
Seung Il Seo ◽  
Yoon Ho Yang ◽  
Chang Doo Jang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Local Heating ◽  
Heating Element ◽  
Heating Process ◽  
Labor Costs ◽  
Line Heating ◽  
Element Analysis ◽  
Energy Principle ◽  
Heating And Cooling

The line heating process has been used to create curved surfaces of ship structures. However, because it depends on a worker's skill and experience, it has been a factor in preventing the automation of shipyards and in consuming labor costs. In this paper, to reduce the trial-and-error procedure of line heating work by simulating the deforming process of a plate, a finite-element analysis method is proposed. A new element, called the line heating element, is defined and applied. The line heating element is assumed to have orthotropic material property. Shrinkage forces and moments resulting from line heating are obtained by integration of inherent strains formed by local heating and cooling. The shrinkage forces and moments at the inherent strain region are converted to equivalent nodal forces by the energy principle. Results calculated using the line heating element show good agreement with the results obtained by the commercial finite-element analysis code.

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