scholarly journals Melting of micro/nanoparticles considering anisotropy of surface energy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. M. Yang ◽  
M. W. Chen ◽  
G. J. Zheng ◽  
Z. D. Wang
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Surface Energy ◽  
Asymptotic Solution ◽  
Melting Temperature ◽  
Asymptotic Method ◽  
Crystal Orientations ◽  
Nanoparticle Melting ◽  
Effect Of Surface ◽  
Good Agreement

AbstractThe effect of surface energy on the melting of micro/nanoparticles is studied using the asymptotic method. The asymptotic solution of the dynamic model for micro/nanoparticle melting reveals the dependence of the particle melting temperature on the particle size and the anisotropy of surface energy. Specifically, as the particle radius decreases, the isotropic surface energy reduces the melting temperature and accelerates the interface melting of the particle. Along certain crystal orientations, the anisotropy of surface energy enhances the melting temperature of the micro/nanoparticles, whereas depresses the melting temperature of the micro/nanoparticle along other crystal orientations. The anisotropy of surface energy enhances the melting speed of the micro/nanoparticles along certain crystal orientations, whereas reduces the melting speed of the micro/nanoparticles along other crystal orientations. The result of the asymptotic solution is in good agreement with the experimental data.

Effects of HMX Particle Size on the Shock Initiation of PBXC03 Explosive

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Li-Jing Wen ◽  
Zhuo-Ping Duan ◽  
Lian-Sheng Zhang ◽  
Zhen-Yu Zhang ◽  
Zhuo-Cheng Ou ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Reaction Rate ◽  
Pressure Gauge ◽  
Rate Model ◽  
Shock Initiation ◽  
Gauge Data ◽  
Medium Formulation ◽  
Good Agreement

AbstractA series of shock initiation experiments are performed on the PBXC03 explosives in different formulations to understand the influence of the explosive particle size on the shock initiation, and the in-situ pressure gauge data are obtained which show that shock sensitivity decreases with the explosive particle size under the test condition used in this paper. Moreover, a mesoscopic reaction rate model which is calibrated by the experimental data on a medium formulation PBXC03 explosive is adopted and then applied to predict numerically the shock initiation of other PBXC03 explosives in different formulations. The numerical results are in good agreement with the experimental data.

Pemuatan listrik bipolar untuk partikel aerosol

2018 ◽  
Vol 4 (3) ◽  
pp. 287
Author(s):  
Heru Setyawan
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Ion Mobility ◽  
Opposite Sign ◽  
Aerosol Particles ◽  
Calculation Results ◽  
Two Parameters ◽  
Diffusion Charging ◽  
Fuchs Theory ◽  
Good Agreement

Bipolar diffusion charging of aerosol particles has been studied theoretically using Fuchs theory. Experimental data measured by several researchers available in the published literature were used to verify the calculation results. The calculation results show that Fuchs theory has been successfully used to predict the experimental data of the charging probability of submicron aerosol particles. The combination probability of ion-particle increases with the increase of particle size, both for particle and ion with the same sign and those with the opposite sign. However the combination probability is larger if the charges of particle and ion are of the opposite sign. Generally, Fuchs theory is not too easy to deal with due to the ill-defined of all parameters used, namely ion mass and ion mobility. These cause many possibilities of parameter combination that can give a good agreement with experimental data. Thus, in order to interpret the experimental results properly, the two parameters should be measured simultaneously with aerosol measurements.Keywords: Aerosol, Bipolar Charging, Combination ProbabilityAbstrakPemuatan listrik difusi bipolar partikel aerosol telah dipelajari secara teoritis menggunakan teori Fuchs. Sebagai verifikasi digunakan data eksperimen beberapa peneliti yang tersedia dalam literatur yang telah dipublikasikan. Hasil perhitungan menunjukkan bahwa teori Fuchs berhasil memprediksi dengan baik data eksperimen probabilitas pemuatan listrik partikel aerosol dalam rentang ukuran partikel berukuran submikron. Probabilitas penggabungan ion-partikel semakin besar dengan semakin besarnya ukuran partikel, baik untuk partikel dan ion yang memiliki tanda yang berlawanan maupun yang memiliki tanda yang sama. Akan tetapi, probabilitas penggabungan untuk partikel dan ion yang memiliki tanda yang berlawanan memiliki nilai yang lebih besar. Pada umumnya teori Fuchs tidak terlalu mudah untuk digunakan yang disebabkan oleh tidak terdefinisikannya dengan baik semua parameter yang digunakan, yaitu  massa ion dan mobilitas ion. Hal ini mengakibatkan banyak kemungkinan kombinasi parameter yang bisa menghasilkan kesesuaian yang bagus dengan data hasil pengukuran. Jadi, agar dapat menginterpretasikan hasil pengukuran dengan tepat, kedua besaran tersebut harus diukur secara serempak denganpengukuran aerosol.Kata Kunci: Aerosol, Pemuatan Listrik Bipolar, Probabilitas Penggabungan

A theoretical model to study melting of metals under pressure

2015 ◽  
Vol 29 (27) ◽  
pp. 1550161 ◽  
Author(s):  
Kuldeep Kholiya ◽  
Jeewan Chandra
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Melting Temperature ◽  
Present Model ◽  
Melting Curve ◽  
Experimental Result ◽  
Thermal Equation ◽  
Simple Theoretical Model ◽  
Pressure Melting ◽  
Good Agreement

On the basis of the thermal equation-of-state a simple theoretical model is developed to study the pressure dependence of melting temperature. The model is then applied to compute the high pressure melting curve of 10 metals (Cu, Mg, Pb, Al, In, Cd, Zn, Au, Ag and Mn). It is found that the melting temperature is not linear with pressure and the slope [Formula: see text] of the melting curve decreases continuously with the increase in pressure. The results obtained with the present model are also compared with the previous theoretical and experimental data. A good agreement between theoretical and experimental result supports the validity of the present model.

Laboratory simulation of light scattering from regolith analogue: Effect of porosity and particle size

2019 ◽  
Vol 15 (S350) ◽  
pp. 372-374
Author(s):  
Amritaksha Kar ◽  
Asoke K Sen
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Light Scattering ◽  
Solar System ◽  
Laboratory Data ◽  
Laboratory Simulation ◽  
Meteorite Impacts ◽  
Composition And Structure ◽  
Solar System Bodies ◽  
Good Agreement

AbstractThe surfaces of most of the atmosphereless solar system bodies are referred to as regolith or layers of usually loosely connected fragmentary debris, produced by meteorite impacts. Measurement of light scattered from such surfaces provide information about the composition and structure of the surface. In the present work, the effect of porosity and particle size, on reflectance is studied for regolith like samples. For modelling the experimental data Hapke 2008 is used and found to be in good agreement with laboratory data. From the present study, it can be concluded that the physical properties of a regolith, such as porosity, particle size etc are effectively represented by albedo.

scholarly journals INFLUENCE OF POLYMORPHIC TRANSFORMATIONS ON ANISOTROPY OF THE SURFACE ENERGY AND THE WORK FUNCTION OF THE ELECTRON OF LITHIUM

2021 ◽  
pp. 439-446
Author(s):  
Ирина Гусейновна Шебзухова ◽  
Людмила Павловна Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Layer ◽  
Surface Energy ◽  
Crystal Lattice ◽  
Work Function ◽  
Analytical Relationship ◽  
Polymorphic Transformations ◽  
Calculation Results ◽  
Limiting Temperatures ◽  
Good Agreement

На базе электронно-статистического метода показана связь и проведена оценка поверхностной энергии и работы выхода электрона граней кристаллов лития с учетом дисперсионного, поляризационного и осцилляционного взаимодействия атомов поверхностного слоя. Считалось, что кристаллическая решетка не имеет дефектов. Модифицированы выражения поправок и аналитического соотношения, связывающего работу выхода электрона и поверхностную энергию с учетом типа кристаллической решетки и ориентации граней. Рассчитана работа выхода электрона и поверхностная энергия гладких граней при предельных температурах существования полиморфных фаз лития. Установлено влияние полиморфных превращений и температуры на анизотропию. Температурный коэффициент работы выхода электрона бездефектного кристалла положителен и составляет порядка 0,1-1 мэВ. Результаты расчетов хорошо согласуются с экспериментальными данными для поликристаллов. On the basis of the electronic-statistical method, a relationship is obtained and the surface energy and the work function of the electron of the faces of lithium crystals are estimated, taking into account the dispersion, polarization, and oscillatory interactions of the atoms of the surface layer. It was assumed that the crystal lattice has no defects. The expressions for the corrections and an analytical relationship between the work function of the electron and the surface energy are modified taking into account the type of the crystal lattice and the orientation of the faces. The work function of the electron and the surface energy of smooth faces are calculated at the limiting temperatures of the existence of polymorphic lithium phases. The influence of polymorphic transformations and temperature on the anisotropy is established. The temperature coefficient of the work function of an electron in a defect-free crystal is positive and amounts to about 0,1-1 meV. The calculation results are in good agreement with the experimental data for polycrystals.

scholarly journals Modeling the process of grinding feed by the method of damage accumulation

2021 ◽  
Vol 284 ◽  
pp. 02021
Author(s):  
Timmo Gavrilov
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Energy Consumption ◽  
Damage Accumulation ◽  
Optimal Number ◽  
Grinding Process ◽  
Technological Parameters ◽  
Number Of Cycles ◽  
Working Bodies ◽  
Good Agreement

The efficiency of the process of grinding meat and bone feed depends on a number of design and technological parameters of the grinder operation. One of the most significant issues and at the same time the least studied one is the influence of the number of cycles of loading meat and bone feed with the working bodies of grinders on the particle size of the finished meat and bone feed. To study this issue, the authors proposed a method for modeling the process of grinding meat and bone feed using a stochastic B-model of cumulative damage, which is based on an understanding of the process under study at the macroscopic level and experimental data. The constructed B-model made it possible to determine the optimal number of cycles of loading meat and bone feed with the working bodies of the grinders, at which the required particle size of the finished meat and bone feed is 3...5 mm, and there is no unnecessary energy consumption of the grinding process. This number is equal to 12...18 cycles. The results obtained by the B-model are in good agreement with the experimental data. The constructed B-model of the grinding process of meat and bone feed will further help optimizing the operation of the cutting device and reducing energy consumption for the operation of the grinders as a whole.

Effects of HMX Particle Size on the Shock Initiation of PBXC03 Explosive

2012 ◽  
Vol 13 (2) ◽  
Author(s):  
Li-Jing Wen ◽  
Zhuo-Ping Duan ◽  
Lian-Sheng Zhang ◽  
Zhen-Yu Zhang ◽  
Zhuo-Cheng Ou ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Reaction Rate ◽  
Pressure Gauge ◽  
Rate Model ◽  
Shock Initiation ◽  
Gauge Data ◽  
Medium Formulation ◽  
Good Agreement

AbstractA series of shock initiation experiments are performed on the PBXC03 explosives in different formulations to understand the influence of the explosive particle size on the shock initiation, and the in-situ pressure gauge data are obtained which show that shock sensitivity decreases with the explosive particle size under the test condition used in this paper. Moreover, a mesoscopic reaction rate model which is calibrated by the experimental data on a medium formulation PBXC03 explosive is adopted and then applied to predict numerically the shock initiation of other PBXC03 explosives in different formulations. The numerical results are in good agreement with the experimental data.

Size effects in powder compaction

2001 ◽  
Vol 16 (5) ◽  
pp. 1238-1240 ◽  
Author(s):  
J. Gil Sevillano
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Size Effects ◽  
Powder Compaction ◽  
Ultrafine Powders ◽  
Strain Gradients ◽  
Strength Enhancement ◽  
Relative Contribution ◽  
Interparticle Contacts ◽  
Good Agreement

It is well known that great difficulties are encountered in the cold compaction of ultrafine powders. Such difficulties have been qualitatively attributed to several origins (e.g., increasing relative contribution of oxidized layers to particle resistance as particle size decreases). The main densification stage during compaction is governed by plastic deformation at interparticle contacts under pressure. On account of the strength enhancement of plastic resistance in presence of plastic strain gradients (physically resolved by “geometrically necessary dislocations”) a contribution to the size effect on powder compaction efficiency is here predicted. Some quantitative experimental data available are in good agreement with this explanation.

scholarly journals Анизотропия поверхностной энергии и работы выхода электрона IIВ металлов

2019 ◽  
Vol 89 (2) ◽  
pp. 306
Author(s):  
И.Г. Шебзухова ◽  
Л.П. Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Energy ◽  
Work Function ◽  
Statistical Method ◽  
Electron Work Function ◽  
Method Of Calculation ◽  
Cadmium Zinc ◽  
Good Agreement

AbstractOn the basis of electron-statistical method of calculation of the surface energy of metals, a technique for estimating the electron work function of hexagonal and rhombohedral metallic crystals has been developed. This technique relates surface energy to work function and can thus be applied to estimate the surface energy of crystal faces from experimental data for a work function. Computations have been made for cadmium, zinc, and mercury macrocrystals. The temperature and orientation dependences of both quantities have been constructed. Our results are in good agreement with literature experimental data.

Effect of Surface Energy on the Wear Process

1964 ◽  
Vol 86 (2) ◽  
pp. 306-310 ◽  
Author(s):  
E. Rabinowicz ◽  
R. G. Foster
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Wear Particle ◽  
Particle Sizes ◽  
Wear Particles ◽  
Wear Process ◽  
External Variables ◽  
Particle Measurement ◽  
Effect Of Surface ◽  
Correct Size

It was previously shown that the size of loose wear particles formed during the sliding of two materials is equal to 60,000 Wab/P, where Wab is the surface energy of adhesion and p the penetration hardness. Experimental results are presented which show that the experimental particle sizes obtained with a few materials do indeed obey the theoretical relationship, and that the particle size is, as predicted, almost independent of such external variables as speed, time, geometry, and load, provided the load is not too great. Indeed, if particles of the wrong size are fed into the system, then they tend to be broken down or built up until the correct size is reached. However, changes of atmosphere and the use of lubricants, which alter the energy of adhesion, do have a marked influence on wear-particle size, and this fact suggests a possible use of wear-particle measurement to rate boundary lubricants. Other surface interaction phenomena which are governed by the W/p ratio are discussed, and it is suggested that the surface roughness generated during sliding is a function of this ratio.

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