Modern Concepts in Material Science最新文献_第6页

Application of DLVO Theory on the Interaction Forces for Rheology of Coal-Water Slurries DLVO理论在水煤浆流变性相互作用力中的应用

Modern Concepts in Material Science Pub Date : 2020-02-26 DOI: 10.33552/MCMS.2020.02.000548

O. Guven

{"title":"Application of DLVO Theory on the Interaction Forces for Rheology of Coal-Water Slurries","authors":"O. Guven","doi":"10.33552/MCMS.2020.02.000548","DOIUrl":"https://doi.org/10.33552/MCMS.2020.02.000548","url":null,"abstract":"Based on the depletion of present fuel reserves in the world, many investigations are carried out for finding alternatives. Thus, coal-water slurries (hereafter CWS) is one of these alternatives that consists of finely dispersed coal particles suspended in water. A commercial CWS includes 55-70% fine coal, 25-40% water and 1% chemical additive [2] while these values are effective on the basic characteristics like viscosity, density and fluidity of mixtures that constitute their quality and selling conditions. As well known, the flow and the stability characteristics vary upon physical and physicochemical properties of coal suspensions, regarding volume fraction of solids, particle size, size distribution, temperature, concentration of salt and thus particle-particle interactions in mixture. Therefore, modeling of these interactions is significant for determining the relevant characteristics of suspensions by means of the movement of very fine particles dominated by surface forces [3]. In this manner, DLVO theory (Derjaguin-Landau-Vier-Overbeek theory) is the most commonly used assumption consisting of attractive London van der Waals and repulsive electrostatic double layer forces for modeling the colloidal dispersion stability. Figure 1 shows a typical potential energy vs. separation distance (h) for particle-particle interaction.","PeriodicalId":297187,"journal":{"name":"Modern Concepts in Material Science","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127829665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Using New Concepts in Nanoscience to Develop New Materials 利用纳米科学的新概念开发新材料

Modern Concepts in Material Science Pub Date : 2020-02-20 DOI: 10.33552/MCMS.2020.02.000547

Xiang Zhang

{"title":"Using New Concepts in Nanoscience to Develop New Materials","authors":"Xiang Zhang","doi":"10.33552/MCMS.2020.02.000547","DOIUrl":"https://doi.org/10.33552/MCMS.2020.02.000547","url":null,"abstract":"The foundation of material science has always been largely rooted in chemistry and the elements of periodic table, many of which have not yet been completely studied and whose full potential has still not been determined. In fact, it is possible to view material science not as “a” science in and of itself, but rather a combination of multiple scientific disciplines, including chemistry, physics and mechanics. The science of materials chemistry is closely associated with chemical structures which vary in scale, with small scale atomic, nanometer and micrometer structures typically having greater importance. When studying the characteristics of a new structure including its associated chemical, physical, mechanical properties etc. understanding these properties at multiple scales from atomic, up to micrometer is very important in determining the material’s range of functionalities. Completing this research and examining the outcomes greatly improves the ease and successfulness of new material applications and this remains true whether you are working with inorganic materials, organic materials or hybrids of the two. In my opinion, future developments in material science should aim to cross the border of inorganic and organic science, focusing instead on the study of the properties of atomic-micro scale material structures rather than following well established standards, such as ISOs for materials, all at macroscales.","PeriodicalId":297187,"journal":{"name":"Modern Concepts in Material Science","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114514890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Growth Study of Silicon Nanowires Synthesized Via Plasma-Assisted VLS Using Tin Catalysts 锡催化剂等离子体辅助VLS合成硅纳米线的生长研究

Modern Concepts in Material Science Pub Date : 2020-02-12 DOI: 10.33552/MCMS.2020.02.000546

Siham Djoumi, F. Kail, L. Chahed, P. Cabarrocas

{"title":"Growth Study of Silicon Nanowires Synthesized Via Plasma-Assisted VLS Using Tin Catalysts","authors":"Siham Djoumi, F. Kail, L. Chahed, P. Cabarrocas","doi":"10.33552/MCMS.2020.02.000546","DOIUrl":"https://doi.org/10.33552/MCMS.2020.02.000546","url":null,"abstract":"It is for this reason that an alternative metal to gold has been investigated for the synthesis of semiconductor NWs. From this point of view, Tin can be used as an alternative candidate because of its low eutectic point (232 ° C) and low solubility in Si. Thin films of the Sn catalyst, with 1 nm of thickness, were prepared by the thermal evaporation method at a pressure of 2×10 -6 mbar vacuum on crystalline (100) silicon wafer c-Si and hydrogenated amorphous silicon coated c-Si a-Si:H/ c-Si substrates at room temperature. The samples were loaded into PECVD chamber, Sn nanoparticles were formed by exposure to 100 sccm of H 2 plasma for 2 min, SiNWs were then grown for 20 min by introducing pure silane (SiH4) into the reactor with a flow rate of 5 sccm at a substrate temperature between 400 and 600 °C. SEMs showing that the Tin catalyzed SiNWs are tapered in nature and randomly oriented. The density and the morphology of the NWs are influenced by the growth temperature and by the substrate. Abstract In the present work, silicon nanowires (SiNWs) have been grown on crystalline silicon (Si) (100) oriented and hydrogenated amorphous silicon a-Si:H coated c-Si (a-Si: H/c-Si) substrates by plasma-enhanced chemical vapor deposition (PECVD) via the vapor-liquid-solid (VLS) process at different temperature. Tin (Sn) catalyst coating with a thickness of 1 nm were used as metal catalysts. A hydrogen plasma was applied to reduce the oxide and to form Sn droplets. SiNWs were then grown by introducing pure silane (SiH4) into the reactor with a flow rate of 5 sccm and a chamber pressure of 1.33 mbar, at a substrate temperature between 400 and 600°C. Their morphological and surface characteristics have been investigated using Hitachi S4800 scanning electron microscopy (SEM). Morphology obtained from SEM shows tapered growth of NWs with a distinctively sharp tip.","PeriodicalId":297187,"journal":{"name":"Modern Concepts in Material Science","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130097406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Estimation of Surface Roughness of Aluminum Reinforced Metal Matrix Composites 铝增强金属基复合材料表面粗糙度的估算

Modern Concepts in Material Science Pub Date : 2020-01-21 DOI: 10.11648/J.AE.20200401.12

J. O. Hamed, G. Agbaje, Abdullahi Ikani Bakwo, B. Olaniyi, I. O. Lawal, Adekunle Benjamin Falade

{"title":"Estimation of Surface Roughness of Aluminum Reinforced Metal Matrix Composites","authors":"J. O. Hamed, G. Agbaje, Abdullahi Ikani Bakwo, B. Olaniyi, I. O. Lawal, Adekunle Benjamin Falade","doi":"10.11648/J.AE.20200401.12","DOIUrl":"https://doi.org/10.11648/J.AE.20200401.12","url":null,"abstract":"There is a strong agitation from rocket designer for a highly reinforced metal matrix composites for rocket chamber to curtail the effect of high temperature and pressure from gaseous product of combustion process. This study has been designed to evaluate the surface roughness of an aluminum reinforced metal matrix composites produced by stir casting techniques at constant cutting speed of 1000 rpm, three (3) different feed rates at various aluminum weight ratio. Response surface methodology was adopted to formulate a surface roughness model in terms of metal matrix constituents such as aluminum, barite and zircon under three (3) different feed rate. The model adequacy was verified using analysis of variance. Also, the approach was used to optimize the effect of reinforced materials on surface roughness of the matrix composites. The increase in weight ratio of aluminum matrix reduces the surface roughness and vice versa. However, increase in barite, zircon weight ratios and feed rate increase the surface roughness. The optimum matrix chemical composition ratios of 0.9310, 0.0296, and 0.0394 for aluminum, barite, and zircon respectively with optimal desirability index of 0.903 shows the validity of the design. The F-values obtained at 95% confidence interval revealed that the selected model adequately represent the data for the matrix composites. Therefore, the study confirm the effectiveness of Response Surface Methodology as a tool in predicting surface roughness and provide materials with enhanced mechanical properties.","PeriodicalId":297187,"journal":{"name":"Modern Concepts in Material Science","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114210286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Enhancement of Microwave Absorption Property of Polymer Blend using MXene MXene增强聚合物共混物的微波吸收性能

Modern Concepts in Material Science Pub Date : 2020-01-21 DOI: 10.33552/MCMS.2020.02.000543

D. Tan

引用次数: 1

Atomic and Electronic Structure in Thin Foils Ni51Ti49 Ni51Ti49薄膜的原子和电子结构

Modern Concepts in Material Science Pub Date : 2020-01-13 DOI: 10.33552/MCMS.2020.02.000542

Kaznacheeva Am

引用次数: 0

Zero Point Level Effects on Structure, Energy and Spectra of Molecules & Materials 零点能级对分子和材料结构、能量和光谱的影响

Modern Concepts in Material Science Pub Date : 2020-01-07 DOI: 10.33552/MCMS.2020.02.000541

B. Hudson

{"title":"Zero Point Level Effects on Structure, Energy and Spectra of Molecules & Materials","authors":"B. Hudson","doi":"10.33552/MCMS.2020.02.000541","DOIUrl":"https://doi.org/10.33552/MCMS.2020.02.000541","url":null,"abstract":"This review encompasses the considerations that must come into play when dealing with molecules or hydrogen bonded crystals where there are two or more equivalent potential energy minima and those cases where isotopic replacement influences the relative energy or spectral properties such as 13C NMR chemical shifts. In such cases the properties of the zeropoint level must be investigated. The specific cases discussed are changes in the relative energies of polymorphic crystal structures, the effect of deuterium substitution on the 13C NMR chemical shifts and the hyperfine coupling constant of a radical species involving addition of either muonium or hydrogen atom. We discuss first molecules with double minimum potentials: ammonia, the potentially aromatic [18] annulene and polyacetylene. Ammonia has minima in its potential energy at equivalent out of plane positions with a maximum at the D3h planar geometry. The vibrational energy levels of the outofplane bending mode of the ground electronic state of NH3 are shown in the lower part of Figure 1. The pattern of levels in the A1 ground state is due to tunneling splitting. The excited electronic state is D3h symmetric at its minimum. Raman transitions excited with 212.8 nm radiation are shown [1]. [18]annulene Figure 2. with N = 4n+2 for n = 4 is potentially aromatic. X-ray diffraction gives D6h symmetry for this material, but this structure does not agree with calculations of proton NMR.","PeriodicalId":297187,"journal":{"name":"Modern Concepts in Material Science","volume":"813 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123288928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phase Stability of Rare-Earth Sesquioxides - New Approach 稀土倍半氧化物的相稳定性——新方法

Modern Concepts in Material Science Pub Date : 2020-01-03 DOI: 10.33552/MCMS.2020.02.000539

G. Kimmel

引用次数: 1

On the Experimental Assessment of Thermodynamic Stability of Nanostructured Solid Solutions 纳米结构固溶体热力学稳定性的实验评价

Modern Concepts in Material Science Pub Date : 2019-12-05 DOI: 10.33552/mcms.2019.02.000537

A. M. Locci

引用次数: 2

Modern Concepts in Material Science 材料科学中的现代概念

Modern Concepts in Material Science Pub Date : 2019-12-04 DOI: 10.33552/mcms

R. Horng

引用次数: 0