scholarly journals Microwave solid fuel ignition

2021 ◽  
Vol 2094 (5) ◽  
pp. 052054
Author(s):  
R V Kondratev
Keyword(s):  
Electromagnetic Field ◽  
Solid Fuel ◽  
Thermal Power ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Ignition Process ◽  
Boiler Plant ◽  
Microwave Exposure ◽  
Unburned Fuel ◽  
Physical And Chemical

Abstract The article continues the study of the effect of microwave exposure on solid fuel. On the basis of the experimental studies, the dependences of changes in the temperature and humidity fields of the fuel on the time of microwave exposure, to arson, have been established. The possibility of using the microwave electromagnetic field to automate the process of burning solid fuel in a boiler plant, afterburning unburned fuel residues is considered. The mechanism and basic conditions of these processes are presented. The influence of this technology on the intensification of the fuel ignition process, its homogenization, an increase in energy characteristics and a change in the elemental composition, an increase in the efficiency of a boiler plant, a decrease in chemical, mechanical underburning and harmful emissions of a boiler plant is considered. The main conditions of the applied technology are: placement of the microwave generator on the combustion device of the boiler unit, the size of the solid fuel samples or its contacting pieces should be less than the wavelength of the microwave electromagnetic field (12.4 cm), the moisture content - within the range from 10 to 95%. The intensification of the process of burning solid fuel also depends on the type of fuel, its physical and chemical properties (various types of coal, wood fuel, including wood waste, peat, and others). Modernization of boiler plants using this technology is possible by unifying projects that take into account the correspondence of microwave generators to the thermal power of boiler units.

scholarly journals Reactivity of fly ashes milled in different milling devices

2019 ◽  
Vol 58 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Yong-Sik Chu ◽  
Batmunkh Davaabal ◽  
Dae-Sung Kim ◽  
Sung-Kwan Seo ◽  
Yoo Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Surface Area ◽  
Thermal Power ◽  
Chemical Properties ◽  
Particle Size Reduction ◽  
Attrition Mill ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Physical And Chemical

Abstract The effect of two different milling devices, namely attrition mill versus vibration mill, on the reactivity of fly ash was studied. High calcium fly ash from 4th Thermal power station of Ulaanbaatar (Mongolia) was used for the experiments. The raw and processed samples were characterized by XRD, SEM, Particle size distribution, BET, Blaine surface area and density measurements. The efficiency of 1 hour milling was evaluated with the Blaine surface area set to be more than 5000 cm2/g. The physical and chemical properties of the attrition milled fly ash changed not much compared to the vibration milled samples. For example the d50 particle size became reduced from 29 µm to 6 µm by attrition milling and in vibration milled fly ash it was reduced to 7 µm. The density increased from 2.44 g/cm3 of raw fly ash to 2.84 g/cm3 and 2.79 g/cm3 in attrition and vibration milled samples, respectively. Mechanical milling revealed not only a particle size reduction but also the formation of a denser microstructure. As a result the vibration milled fly ash showed a weaker interaction with the alkaline solution (8 M NaOH used here) compared to the attrition milled fly ash. Consequently, compressive strength of the binder prepared using the attrition milled fly ash was higher, 61 MPa, while for vibration milled fly ash it was 49 MPa. For comparison unmilled fly ash, it was 21 MPa.

Ignition by Hot Free Jets

2017 ◽  
Vol 231 (10) ◽  
pp. 1737-1771 ◽  
Author(s):  
Franziska Seitz ◽  
Robert Schießl ◽  
Detlev Markus
Keyword(s):  
Mixture Fraction ◽  
Pressure Ratio ◽  
Experimental Studies ◽  
Variable Density ◽  
Ignition Process ◽  
Exhaust Gas ◽  
Ambient Conditions ◽  
Free Jet ◽  
Hot Jet Ignition ◽  
Unburned Fuel

Abstract This paper describes some of our experimental studies on the re-ignition caused by jets of hot gas that interact with unburned fuel/air mixtures. The problem is approached from two complementary sides: On the one hand, phenomenological studies are conducted, which ask for the conditions under which a hot jet may cause ignition. A dedicated experiment is described which allows to create well-controlled exhaust gas jets and ambient conditions. In this experiment, parameters influencing the ignition process are varied, and the dependence of jet behavior on these parameters (i.e. pressure ratio, diameter and length of the gap through which the exhaust gas has to pass before getting into contact with ambient fuel/air) is studied. In particular, the frequency of a jet causing re-ignition in the ambient gas is studied. On the other hand, we also perform studies which are more “analytical” in nature. These attempt a more in-depth understanding, by first decomposing the hot jet ignition phenomenon into the underlying physical processes, and then studying these processes in isolation. This approach is applied to measurements of mixture fraction fields. First, non reacting isothermal variable density jets are studied. Here, the density of the gas mixture varies as to mimic the density of hot exhaust gas at varying temperatures. A laser-based non-intrusive method is introduced that allows to determine quantitative mixture fraction fields; although applied here to cold jets only, the method is also applicable to hot jets. The results show the effect of turbulence on the mixing field in and at the free jet, and allow to derive quantities that describe the statistics of the turbulent jet, like probability density functions (PDFs) and geometrical size of fluctuations.

Preparation and Performance of Andalusite Bonded SiC Solar Heat-Absorbing Ceramics

2013 ◽  
Vol 320 ◽  
pp. 52-59
Author(s):  
Jian Feng Wu ◽  
Meng Liu ◽  
Xiao Hong Xu ◽  
Ya Xiang Zhang ◽  
Kun Li ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Bending Strength ◽  
Thermal Power ◽  
Chemical Properties ◽  
Xrd Analysis ◽  
Expansion Rate ◽  
Testing Technology ◽  
Firing Shrinkage ◽  
And Performance ◽  
Physical And Chemical

Using andalusite, SiC, Su Zhou Kaolin and Guang Xi quartz as materials, andalusite bonded SiC heat absorbing ceramic was prepared by pressureless firing in the ceramic preparation process. The influence of gradient SiC on microstructure and properties of the samples were studied. Using the testing technology of XRD, SEM, and etc., physical and chemical properties, phase composition and microstructure were tested and analysised.The results indicate that andalusite bonded SiC heat absorbing ceramic, which prepared to have a low firing shrinkage rate, high refractoriness and a good microstructure. The best firing temperature of the best formula C4 is 1460°C, firing expansion rate is 0.98%, bending strength is 32.52MPa,porosity is 30.74%, bulk density is 2.05g·cm-3, refractoriness is 1650°C,growth rate of oxidation weight is 2.769mg·cm-2and have no crack after 30 times thermal shock. The bending strength has increased 11.15% after thermal shock. XRD analysis indicated that the main phase compositions are α-SiC, mullite and cristobalite.SEM studies show that there are many connected pores in the samples, the diameters of the pores are 10~20μm. Andalusite bonded SiC heat absorbing ceramic have a low firing expansion rate, high bending strength and good microstructure, which is suit for tower type solar thermal power generation.

Investigation and prevention of the residues formed in melting furnaces and transfer ladles used in low-pressure Al-casting technologies

2016 ◽  
Vol 78 (1) ◽  
pp. 5-10
Author(s):  
B. Yay ◽  
E. Akinci ◽  
A. Güneren ◽  
U. Karaali ◽  
H.E. Çubuklusu ◽  
...  
Keyword(s):  
Corrosion Behaviour ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Alloy Wheel ◽  
Refractory Life ◽  
Economical Aspect ◽  
Joint Study ◽  
Physical And Chemical ◽  
Metallurgical Processes ◽  
And Chemical Properties

Purpose: Refractory life, in Al-casting processes such as alloy wheel production, is obviously affected by the inclusions formed in the transfer ladles and holding/melting furnaces in which melting, fluxing and degassing operations are carried out. The short refractory life affects, adversely, the economical aspect of the process. Therefore, a study on the physical and chemical properties of the above mentioned inclusions has been started. The main purpose of the study is to understand the relationships among the metallurgical processes taking place during casting, properties of the refractories used and the formation of inclusions.Design/methodology/approach: During this industry-university joint study, experimental studies using scanning electron microscopy (SEM), X-ray diffractometry (XRD) and optical microscopy were used to investigate the nature and properties of the inclusions. Also, corrosion behaviour of six different refractories was investigated by exposing them to molten aluminium.

scholarly journals Biocompatible hydrogels in spinal cord injury repair

2008 ◽  
pp. S121-S132
Author(s):  
A Hejčl ◽  
P Lesný ◽  
M Přádný ◽  
J Michálek ◽  
P Jendelová ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Peripheral Tissues ◽  
Injury Repair ◽  
Cord Injury ◽  
Permanent Neurological Deficit ◽  
Physical And Chemical ◽  
The Brain

Spinal cord injury results in a permanent neurological deficit due to tissue damage. Such a lesion is a barrier for "communication" between the brain and peripheral tissues, effectors as well as receptors. One of the primary goals of tissue engineering is to bridge the spinal cord injury and re-establish the damaged connections. Hydrogels are biocompatible implants used in spinal cord injury repair. They can create a permissive environment and bridge the lesion cavities by providing a scaffold for the regeneration of neurons and their axons, glia and other tissue elements. The advantage of using artificial materials is the possibility to modify their physical and chemical properties in order to develop the best implant suitable for spinal cord injury repair. As a result, several types of hydrogels have been tested in experimental studies so far. We review our work that has been done during the last 5 years with various types of hydrogels and their applications in experimental spinal cord injury repair.

Communication of integrated dielectric permitivity and NMR–characteristics of oil with its physical and chemical properties

2020 ◽  
Author(s):  
Andrey A. Mezin ◽  
◽  
Mariya Y. Shumskayte ◽  
Olga V. Rodionova ◽  
Aleksandra I. Buruhina ◽  
...  
Keyword(s):  
Group Composition ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Complex Dielectric Constant ◽  
Physical And Chemical Properties ◽  
Nmr Parameters ◽  
Dielectric Permitivity ◽  
Physical And Chemical ◽  
The Relationship ◽  
And Chemical Properties

The paper presents the results of experimental studies on the dielectric and NMR characteristics of oil samples. The relationship between the complex dielectric constant and the NMR parameters of oil with its density, viscosity and group composition has been established. It was found that the results of these methods directly depend on the content of resinous–asphaltenic compounds in the composition of the studied oil sample.

TOWARDS THE SINGLE-WALLED B- AND/OR N-DOPED CARBON NANOTUBES

2007 ◽  
Vol 06 (06) ◽  
pp. 431-442 ◽  
Author(s):  
W. L. WANG ◽  
X. D. BAI ◽  
E. G. WANG
Keyword(s):  
Carbon Nanotubes ◽  
Binary System ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Structural Features ◽  
Physical And Chemical Properties ◽  
Reaction Route ◽  
Substitutional Doping ◽  
Physical And Chemical ◽  
And Chemical Properties

Soon after the discovery of carbon nanotubes (CNTs) in the early 1990's, the B - and/or N -doped CNTs began to attract increasing interest owing to their modified structural, physical and chemical properties. In comparison with the multi-walled nanotubes and nanofibers, substitutional doping of the single-walled nanotubes (SWNTs) has proved to be much more difficult, and it is only in very recent years that some experimental studies concerning the B - and/or N -doped SWNTs are emerging. This paper intends to provide an up-to-date overview of current research on the doped SWNTs, with scopes covering both the binary system of CB x- and CN x-SWNTs and the ternary B x C y N z-SWNTs. A survey of the latest achievements in the syntheses of doped SWNTs through either the direct syntheses methods or the post-synthetic substitution reaction route is first presented; then the aspects concerning their structural features, elemental compositions, dopants bonding configuration and atomic distributions, as well as their physical and chemical properties are discussed.

scholarly journals Experimental studies to determine the physico-mechanical characteristics of soils improved with special hydraulic binders

2019 ◽  
Vol 85 ◽  
pp. 07017
Author(s):  
Gabriela Andrieş ◽  
Loretta Batali
Keyword(s):  
Mechanical Characteristics ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Subsequent Performance ◽  
Hydraulic Binder ◽  
Proctor Test ◽  
Experimental Laboratory ◽  
The Difference ◽  
Physical And Chemical ◽  
Construction Works

The complexity of the construction works and site conditions, combined with environmental factors, led to the necessity of using special mineral binders with physical and chemical properties superior to the usual binders. Taking into account the above arguments, the paper presents the results of experimental laboratory studies in order to determine the physical and mechanical characteristics of soil used for a road embankment, after improvement with a special lime-based hydraulic binder. Since improvement recipes vary from one soil to another, it is important to always determine the characteristics after treatment. Also, the method of mixing the binder and soil decisively determines subsequent performance. As part of a larger study aiming at assessing the various factors of influence on the treated soil characteristics, two comparative studies were carried out, each consisting in the recipe formulation using 3 different binder ratios, the difference being given by the parameters used for specimen compaction: normal or modified Proctor test. The study followed the influence of the mechanical compaction work on the mechanical behaviour of the specimens over time after different times of curing.

scholarly journals The Effects of Plasma on Plant Growth, Development, and Sustainability

2020 ◽  
Vol 10 (17) ◽  
pp. 6045 ◽  
Author(s):  
Bhawana Adhikari ◽  
Manish Adhikari ◽  
Gyungsoon Park
Keyword(s):  
Plant Growth ◽  
Field Experiments ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Low Pressure ◽  
Physical And Chemical Properties ◽  
Molecular Processes ◽  
Plant Growth And Development ◽  
Physical And Chemical ◽  
And Chemical Properties

Cold atmospheric or low pressure plasma has activation effects on seed germination, plant growth and development, and plant sustainability, and prior experimental studies showing these effects are summarized in this review. The accumulated data indicate that the reactive species generated by cold plasma at atmospheric or low pressure may be involved in changing and activating the physical and chemical properties, physiology, and biochemical and molecular processes in plants, which enhances germination, growth, and sustainability. Although laboratory and field experiments are still required, plasma may represent a tool for efficient adaptation to changes in the climate and agricultural environments.

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