scholarly journals Thermal radiation ofsubwavelengthparticles

2021 ◽  
pp. 12-21
Keyword(s):  
Particle Size ◽  
Thermal Radiation ◽  
Electromagnetic Radiation ◽  
Particle Shape ◽  
Radiation Spectrum ◽  
Simple Scheme ◽  
Blue Region ◽  
Integral Radiation ◽  
Planck’S Law

A method is proposed for calculating the dependences of the emissivity of subwavelength parti-cles (SP) from various materials in the form of disks, spheres, cubes and cylinders on their sizes (D) and temperature (T), for cases when external electromagnetic radiation practically does not affect their temperature. For all the listed types of particles, the cutoff wavelengths λcutoffdepending on the size of the SP and the particle shape coefficients ξare determined. With a decrease in the particle size, from the radiation spectrum, which was originally described by Planck's law, wavelengths exceeding λcutoffare gradually excluded. This leads to a decrease in the integral radiation, a decrease in the emissivity and a shift of the radiation spectrum to the blue region. A simple scheme is also proposed for determining ε -the emission coefficients of the midrange according to the calculated graph ε (U), where: U = (ξ × D × T) / B; B is the con-stant of the Wien displacement formula.

GENERATION AND PROPERTIES OF INFRARED RADIATION

2019 ◽  
Vol 6 (2) ◽  
pp. 101-137
Author(s):  
RUSTAM KHAKIMOVICH RAKHIMOV
Keyword(s):  
Electromagnetic Radiation ◽  
Infrared Radiation ◽  
Radiation Spectrum ◽  
Laws Of Nature ◽  
Primary Source ◽  
Ceramic Materials ◽  
Experimental Results ◽  
Ir Radiation ◽  
Scattering Of Light

The article presents the main basic laws of nature and modern theories of the nature of electromagnetic radiation, its generation, characteristics, and laws of reflection, absorption and scattering of light. The principle of transformation of the radiation spectrum of the primary source using the developed ceramic materials are shown, as well as experimental results of the interaction of IR radiation with matter and various mechanisms of influence on various objects and processes are described.

Modelling Particle Size Distribution of Residual Fly Ash from Pulverized Biomass Combustion

2021 ◽  
Vol 15 (1) ◽  
pp. 75-82
Author(s):  
Mingzi Xu ◽  
Changdong Sheng
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Simple Model ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Great Influence ◽  
Biomass Combustion ◽  
Ash Formation ◽  
Residual Ash

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.

Thermometry of microwave discharge in powder mixtures by the thermal radiation spectrum

2008 ◽  
Vol 46 (1) ◽  
pp. 124-130 ◽  
Author(s):  
G. M. Batanov ◽  
N. K. Berezhetskaya ◽  
V. A. Kop’ev ◽  
I. A. Kossyi ◽  
A. N. Magunov
Keyword(s):  
Thermal Radiation ◽  
Microwave Discharge ◽  
Radiation Spectrum ◽  
Powder Mixtures ◽  
Thermal Radiation Spectrum

scholarly journals EFFECTS OF PARTICLE SIZE AND PARTICLE SHAPE IN FLOW SIMULATIONS OF DRY SAND USING DEM

2015 ◽  
Vol 71 (2) ◽  
pp. I_587-I_594
Author(s):  
Shuji MORIGUCHI ◽  
Yuta HIRUMA ◽  
Shinsuke TAKASE ◽  
Kenjiro TERADA
Keyword(s):  
Particle Size ◽  
Particle Shape ◽  
Flow Simulations ◽  
Dry Sand

scholarly journals Optimization of nanostructured/nano sized rice husk ash preparation

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Particle Shape ◽  
Rice Husk Ash ◽  
Loss On Ignition ◽  
Shape Distribution ◽  
Disk Mill ◽  
Grinding Time

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

Prediction of Packing Density of Milled Powder Based on Packing Simulation and Particle Shape Analysis

2007 ◽  
Vol 534-536 ◽  
pp. 1621-1624
Author(s):  
Yuto Amano ◽  
Takashi Itoh ◽  
Hoshiaki Terao ◽  
Naoyuki Kanetake
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Shape Analysis ◽  
Packing Density ◽  
Particle Shape ◽  
Milled Powder ◽  
Spherical Particles ◽  
Nonspherical Particles ◽  
Property Control

For precise property control of sintered products, it is important to know the powder characteristics, especially the packing density of the powder. In a previous work, we developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In order to predict the packing density of the actual powder that consisted of nonspherical particles, we combined the packing simulation with a particle shape analysis. We investigated the influence of the particle size distribution of the powder on the packing density by executing the packing simulation based on particle size distributions of the actual milled chromium powders. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. A prediction of the packing density of the milled powder was attempted with an analytical expression between the particle shape of the powder and the packing simulation. The predicted packing densities were in good agreement with the actual data.

scholarly journals Effect of particle size distribution on rheological properties of chocolate

2020 ◽  
Vol 11 (11) ◽  
pp. 9547-9559
Author(s):  
Annika Feichtinger ◽  
Elke Scholten ◽  
Guido Sala
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Rheological Properties ◽  
Size Distribution ◽  
Particle Shape ◽  
Size Ratio ◽  
Particle Size Ratio ◽  
Effect Of Particle Size

Particle size distribution and particle size ratio have an important effect on rheological properties of model chocolate samples, but also other factors like particle shape, surface roughness and hydrophilicity should be taken into account.

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