scholarly journals Temperature Variations Analysis for Condensed Matter Micro- and Nanoparticles Combustion Burning in Gaseous Oxidizing Media by DTM and BPES

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. Hatami ◽  
D. D. Ganji ◽  
K. Boubaker
Keyword(s):  
External Surface ◽  
Condensed Matter ◽  
Combustion Process ◽  
Iron Particle ◽  
Transformation Method ◽  
Physical Parameters ◽  
Iron Particles ◽  
Temperature Variations ◽  
Mathematical Section ◽  
Expansion Scheme

Combustion process for iron particles burning in the gaseous oxidizing medium is investigated using the Boubaker polynomial expansion scheme (BPES) and the differential transformation method (DTM). Effects of thermal radiation from the external surface of burning particle and alterations of density of iron particle with temperature are considered. The solutions obtained using BPES technique and DTM are compared with those of the fourth-order Runge-Kutta numerical method. Results reveal that BPES is more accurate and reliable method than DTM. Also the effects of some physical parameters that appeared in mathematical section on temperature variations of particles as a function of time are studied.

Implementation of DTM as a numerical study for the Casson fluid flow past an exponentially variable stretching sheet with thermal radiation

2021 ◽  
pp. 2150111
Author(s):  
Khadijah M. Abualnaja
Keyword(s):  
Fluid Flow ◽  
Thermal Radiation ◽  
Numerical Method ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Transformation Method ◽  
Casson Fluid ◽  
Physical Parameters ◽  
Special Cases

This paper introduces a theoretical and numerical study for the problem of Casson fluid flow and heat transfer over an exponentially variable stretching sheet. Our contribution in this work can be observed in the presence of thermal radiation and the assumption of dependence of the fluid thermal conductivity on the heat. This physical problem is governed by a system of ordinary differential equations (ODEs), which is solved numerically by using the differential transformation method (DTM). This numerical method enables us to plot figures of the velocity and temperature distribution through the boundary layer region for different physical parameters. Apart from numerical solutions with the DTM, solutions to our proposed problem are also connected with studying the skin-friction coefficient. Estimates for the local Nusselt number are studied as well. The comparison of our numerical method with previously published results on similar special cases shows excellent agreement.

scholarly journals Identification of Factors Influencing Sustainability of Buried Continuous Pipelines

2020 ◽  
Vol 12 (3) ◽  
pp. 960
Author(s):  
Muhammad Rizwan Akram ◽  
Abdullah Can ZÜLFİKAR
Keyword(s):  
External Surface ◽  
Third Party ◽  
Research Support ◽  
Temperature Variations ◽  
The Past ◽  
Last Stage ◽  
Work Done ◽  
Inspection Techniques ◽  
The Impact ◽  
Damage Criteria

Threat to the sustainability of buried continuous pipelines (BCPs) can be associated with different factors such as corrosion, natural hazards, and third-party influences. In the past, these factors have been discussed independently by various researchers. Despite these studies, there is still space for a comprehensive review report to be performed in this domain. The purpose of this article is to manage, classify, and describe the literature work done in this sphere. Firstly, the screening of various factors based on their damage criteria has been carried out. An environmental analysis is performed to review the impact of different parameters that can influence the sustainability of BCPs. Further, a technical review on primary factors has been done to examine and measure the causes, damages, mitigation, and inspection techniques. In the last stage, review based decision has been performed. Results of the current study shows that research contribution for corrosion and earthquake factors are in an advanced stage, followed by flood and external surface loads, that are still in progress. However, temperature variations and blast factors are in a premature phase and need broad inspection and research support.

Influence of Different Gradation Carbonyl Iron Particles on the Properties of Magneto-Rheological Fluids

2012 ◽  
Vol 452-453 ◽  
pp. 623-627
Author(s):  
Cheng Bin Du ◽  
Guo Jun Yu ◽  
Zhi Wei Gong
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Shear Stress ◽  
Single Particle ◽  
Carbonyl Iron ◽  
Iron Particle ◽  
Iron Particles ◽  
Carbonyl Iron Particle ◽  
Magneto Rheological ◽  
Multiple Particle

The influence of carbonyl iron particles sizes on the properties of magneto-rheological fluids (MRFs) were studied. Different-sized carbonyl iron magnetic particles were prepared by ball milling with different milling times. On this basis, different particle MRF were prepared The off-state viscosity and the shear stress of the above MRFs were characterised and studied by an advanced rotational rheometer system. The test results show that the off-state viscosity and the shear stress of single-particle MRFs were enhanced with increasing average carbonyl iron particle size at a constant magnetic field. The shear stresses of MRFs containing two or three different particle sizes were significantly improved compared with the MRFs containing only a single particle size. At a reasonable level of medium and small size carbonyl iron particle spread throughout the structure of the multiple-particle MRFs, the defects in the chain structure were remedied when a chain reaction occurred, and the mechanical properties of MRFs were enhanced. Meanwhile, increased mass fractions of the small size carbonyl iron particle resulted in a reduction in overall average particle size of MRFs, and the mechanical properties of MRFs were also reduced. The mechanical properties of multiple-particle MRFs were observed to be strongly dependent on the size and mass fraction of the medium and small carbonyl iron particles.

scholarly journals MAPEAMENTO DA MUDANÇA DA TEMPERATURA DESUPERFÍCIE NA REGIÃO DO PONTAL DO PARANAPANEMA NOS ÚLTIMOS 30 ANOS

2018 ◽  
Vol 10 (3) ◽  
pp. 66-77
Author(s):  
Rosana Amaral Carrasco ◽  
Lucas Prado Osco ◽  
Rejane Ennes Cicerelli ◽  
Paulo Antônio Silva ◽  
Ana Paula Marques Ramos
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Areas ◽  
Surface Processes ◽  
Physical Parameters ◽  
Temperature Variations ◽  
Type Of Land Use ◽  
Natural Dynamics

Anthropogenic actions cause changes in the natural dynamics of the landscape, such as variations in climate and land use. Land Surface Temperature (LST) is one of the main physical parameters Recebido em: 27/08/2018Revisado em: 04/09/2018Aprovado em: 06/09/2018 67Colloquium Exactarum, v. 10, n.3,Jul-Set. 2018, p.66–77. DOI: 10.5747/ce.2018.v10.n3.e246of terrestrial surface processes. The importance of LST is increasingly recognized and there is a strong interest in developing methodologies for measuring LST using orbital platforms, such as the Landsat series. This work aims to verify if there was a change in the LST in the region of Pontal doParanapanema from the LST recorded by the Landsat series over the last 30 years. We adopted orbital images from Landsat5 TM and Landsat8 OLI satelliteto extract the LST value, and thenwe evaluated the LST variation at the studied area. A correlation was found between the LST variation and the type of land use and land cover. The urban areas, pasture, agriculture, vegetation and watercourses showed discrepancies in temperature when compared to each other. At Pontal, there were variations of 5 ° C of the average LST, between maximum and minimum temperatures. We concluded that temperature variations are associated with the dynamics of land use.

On Heat Transfer of a Two-Step Radiating Slab of Variable Thermal Conductivity

2020 ◽  
Vol 987 ◽  
pp. 137-141
Author(s):  
Ramoshweu Solomon Lebelo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Chemical Reaction ◽  
Combustion Process ◽  
Variable Thermal Conductivity ◽  
Nonlinear Ordinary Differential Equation ◽  
Physical Parameters ◽  
Exothermic Chemical Reaction ◽  
Temperature Levels ◽  
Heat Transfers

An investigation of heat transfers in a combustible stockpile whose materials are of variable thermal conductivity is conducted in this article. The stockpile is modeled in rectangular slap and a two-step exothermic chemical reaction responsible for the combustion process is assumed. The reactive slab is also assumed to lose heat to the ambient by radiation. The Runge-Kutta Fehlberg (RKF45) method coupled with the Shooting technique is applied to tackle numerically the nonlinear ordinary differential equation (ODE) governing the problem. The process of heat transfer during combustion is made easy to understand by investigating effects of selected thermo-physical parameters on the system’s temperature. The results show that some thermo-physical parameters accelerate the exothermic chemical reaction and therefore raise the temperature levels, and that others help to reduce heat release rate to lower the temperature profiles. The graphs for the results are plotted and discussed accordingly.

Numerical Simulation of Temperature Field of Low Alloyed Bainite Ductile Iron in Austempering

2012 ◽  
Vol 271-272 ◽  
pp. 116-120
Author(s):  
De Qiang Wei ◽  
Yun Qing Zhao ◽  
Rong Wang ◽  
Hu Cheng Chen
Keyword(s):  
Ductile Iron ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Treatment Technology ◽  
Temperature Variations ◽  
Isothermal Temperature ◽  
Dimensional Finite Element ◽  
Cooling Speed ◽  
Three Dimensional Finite Element ◽  
Thermal Physical Parameters

It has an great significance for making heat treatment technology by researching the law of temperature variations of ductile iron in austempering. Based on the three-dimensional finite element method (FEM), the temperature variations of low alloyed bainite ductile iron in austempering are studied in this paper. The temperature relativity of the thermal physical parameters is considered during building the model. The simulation result demonstrates that during the stage of rapid cooling, the cooling speed of the surface is faster than that of the center, and the whole cooling speed increases firstly, then decreases. During the stage of isotherm, the surface temperature of the sample increases to the isothermal temperature directly, while the center temperature decreases firstly, then increases, until to the isothermal temperature.

Trends in acoustic properties of iron particle seeded auxetic polyurethane foam

2004 ◽  
Vol 218 (2) ◽  
pp. 241-244 ◽  
Author(s):  
F Scarpa ◽  
W A Bullough ◽  
P Lumley
Keyword(s):  
Magnetic Fields ◽  
Iron Particle ◽  
Magnetorheological Fluid ◽  
Acoustic Properties ◽  
Absorption Characteristic ◽  
Frequency Bandwidth ◽  
Iron Particles ◽  
Constant Intensity ◽  
Acoustic Absorption Coefficient ◽  
Flexible Foam

The sound absorption characteristic of a clean, open-cell configuration, typical polyurethane flexible foam is shown against that of an auxetic foam made from it, and this same foam after it has been seeded with a magnetorheological fluid (then dried), having 2–5 μm carbonyl iron particles and subjected to zero, weak and concentrated magnetic fields in an acoustic impedance tube facility. The resultant foam indicates the capability of shifting the peak acoustic absorption coefficient within a given frequency bandwidth when constant intensity magnetic fields are applied.

scholarly journals Study of the mechanical properties of Iron-Epoxy composite materials

2019 ◽  
Vol 13 (26) ◽  
pp. 101-106
Author(s):  
Abdulhadi K. Judran
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Particle Concentration ◽  
Epoxy Composite ◽  
Iron Particle ◽  
Mechanical Tests ◽  
Iron Particles ◽  
The Impact ◽  
Hardness Values ◽  
Composite Samples

Iron-Epoxy composite samples were prepared by addeddifferent weight percentages (0, 5, 10, 15, and 20 wt %) from Ironparticles in the range of (30-40μm) as a particle size. The contentswere mixed carefully, and placed a circular dies with a diameter of2.5 cm. Different mechanical tests (Shore D Hardness, Tensilestrength, and Impact strength ) were carried out for all samples. Thesamples were immersed in water for ten weeks, and after two weeksthe samples were take-out and drying to conducting all mechanicaltests were repeated for all samples. The hardness values increasedwhen the Iron particle concentration increased while the Impactstrength is not affected by the increasing of Iron particlesconcentration. The tensile strength results reveal that the tensilestrength and the strain values of composite samples decreases whenthe Iron particles concentration increase. After conductedimmersion processes the results of hardness are reduced wears theresults of tensile strength and the impact strength are increased.

Rheological properties of dimorphic magnetorheological gels mixed dendritic carbonyl iron powder

2017 ◽  
Vol 29 (1) ◽  
pp. 12-23 ◽  
Author(s):  
Pingan Yang ◽  
Miao Yu ◽  
Jie Fu ◽  
Hongping Luo
Keyword(s):  
Yield Stress ◽  
Storage Modulus ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Engineering Application ◽  
Iron Particle ◽  
Iron Particles ◽  
Shear Yield Stress ◽  
Carbonyl Iron Particle ◽  
Shear Yield

Magnetorheological gels typically are colloids of spherical micrometer magnetic particles dispersed in a high-viscosity polymer matrix. However, some major parameters of this kind of mono-disperse magnetorheological gel, such as the shear storage modulus and yield stress, cannot meet the needs of practical engineering application. In this study, a systematic experiment was investigated on the use of dendritic carbonyl iron particles to enhance the comprehensive performance in conventional (microsphere-based) magnetorheological gels formulated in polyurethane matrix. Two kinds of carbonyl iron particles that have very similar magnetic properties but very different morphologies (one is spherical and the other is dendritic) are employed. The dimorphic magnetorheological gels were prepared by adding dendritic carbonyl iron particles into the conventional spherical carbonyl iron particle–based magnetorheological gel and a series of dimorphic magnetorheological gel samples were prepared. The magnetorheological properties of those samples, both under oscillatory and rotational shear rheometry, were systematically tested. It was found that the dendritic carbonyl iron particle additives can significantly improve the shear storage modulus and response time of the dimorphic magnetorheological gels compared with conventional magnetorheological gels. Meanwhile, when the mass ratio of dendritic particles to carbonyl iron particles is 25% and 50%, the shear stress, static shear yield stress, and dynamic shear yield stress of dimorphic magnetorheological gels can also be greatly enhanced.

scholarly journals RESEARCH INTO THREE‐COMPONENT BIODIESEL FUELS COMBUSTION PROCESS USING A SINGLE DROPLET TECHNIQUE

Transport ◽  
2007 ◽  
Vol 22 (4) ◽  
pp. 312-315 ◽  
Author(s):  
Laurencas Raslavičius ◽  
Donatas Markšaitis
Keyword(s):  
Ignition Delay ◽  
Fuel Injection ◽  
Burning Velocity ◽  
Combustion Process ◽  
Combustion Mechanism ◽  
Physical Parameters ◽  
Detailed Chemical Kinetics ◽  
Biodiesel Fuels ◽  
Engine Emission ◽  
Physical And Chemical

In order to reduce the engine emission while at same time improving engine efficiency, it is very important to clarify the combustion mechanism. Even if, there are many researches into investigating the mechanism of engine combustion, so that to clarify the relationship between complicated phenomena, it is very difficult to investigate due to the complicated process of both physical and chemical reaction from the start of fuel injection to the end of combustion event. The numerical simulations are based on a detailed vaporization model and detailed chemical kinetics. The influence of different physical parameters like droplet temperature, gas phase temperature, ambient gas pressure and droplet burning velocity on the ignition delay process is investigated using fuel droplet combustion stand. Experimental results about their influence on ignition delay time were presented.

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