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Combustion characteristic and aging behavior of bimetal thermite powders

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Defence Technology（防务技术） 2021年第3期17卷 755-762页

作者： Hong-qi Nie Hay Yee Chan Sreekumar Pisharath Huey Hoon Hng Energetics research institute Nanyang Technological UniversitySingapore

Nanothermites have been employed as fuel additives in energetic formulations due to their higher energy density over CHNO energetics. Nevertheless, sintering and degradation of nanoparticles significantly limit the practical use of nanothermites. In this work, combustion characteristic and aging behavior of aluminum/iron oxide(Al/Fe2O3) nanothermite mixtures were investigated in the presence of micron-scale nickel aimed to produce bimetal thermite powders. The results showed that the alumina content in the combustion residue increased from 88.3% for Al/Fe2O3 nanothermite to 96.5% for the nanothermite mixture containing 20 wt% nickel. Finer particle sizes of combustion residue were obtained for the nanothermite mixtures containing nickel, indicative of the reduced agglomeration. Both results suggested a more complete combustion in the bimetal thermite powders. Aging behavior of the nanothermite mixture was also assessed by measuring the heat of combustion of the mixture before and after aging process. The reduction in heat of combustion of nanothermite mixtures containing nickel was less severe as compared to a significant decrease for the nanothermite mixture without nickel, indicating better aging resistance of the bimetal thermite powders.

关键词： Nanothermite Bimetal Combustion efficiency Aging Thermochemical calculations

Precracking and interfacial delamination in a bi-material structure:Static and dynamic loadings

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Acta Mechanica Sinica 2011年第1期27卷 80-89页

作者： Barbara Gambin Jordanka Ivanova Varbinka Valeva Gergana Nikolova institute of Fundamental technological research institute of Mechanics

The behavior of a precracked bi-material structure interface under given static and dynamic axial loading is an interest object in the present ***,it is shown that the shear-lag model is a proper tool to analyze a delamination process in a precracked bi-material structure undergoing static ***,the＂shear-lag model＂is applied to the structure under dynamic *** solve the problem for an interface delamination of the structure and to determine the debond length along the interface,our own 2D boundary element method（BEM）code is proposed in the case of static loading,and the shear-lag model together with the Laplace transforms and half-analytical calculations are used in the case of dynamic *** interface layer is assumed as a very thin plate compared with the other *** parametric（geometric and elastic）analysis of the debond length and interface shear stress is done. The results from the 2D BEM code proved the validity of analytical solutions to the shear-lag *** the dynamic case,the influence of loading characteristics,i.e.,frequencies and amplitude fluctuations on the shear stress and the value of debond length for an interval of time,is discussed. The analysis of the obtained results is illustrated by an example of the modern ceramic-metal composite,namely cermet, and depicted in figures.

关键词： Debond length · Precracked bi-material structure · Shear-lag model · Delamination · BEM

Deactivation studies of bifunctional Fe-HZSM5 catalyst in Fischer-Tropsch process

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Journal of Natural Gas Chemistry 2008年第3期17卷 242-248页

作者： Ali Nakhaei Pour Seyed Mehdi Kamali Shahri Yahya Zamani Mohammad Irani Shohreh Tehrani research institute of Petroleum Industry National Iranian Oil Company

A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst （HZSM5） for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this trend followed the phase transformation Fe2.2C （ ε′） → Fe5C2 （χ） → Fe3C （θ）, and the final predominant phase of the catalyst was Fe3C （θ）. Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained.

关键词： catalyst deactivation Fischer-Tropsch synthesis iron catalyst HZSM5 zeolite

Modified activated carbon with interconnected fibrils of iron-oxyhydroxides using Mn^(2+) as morphology regulator, for a superior arsenic removal from water

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Journal of Environmental Sciences 2019年第2期31卷 403-414页

作者： Cesar Nieto-Delgado Joel Gutiérrez-Martínez J.Rene Rangel-Méndez Environmental Sciences Division Potosino Institute of Scientific and Technological ResearchIPICyT

The arsenic removal efficiency of iron-modified activated carbons depends greatly on the number of available iron oxide surface sites, which are given by the surface area of the anchored particles. In this sense, aiming the generation of an adsorbent with superior arsenic adsorption capacity, we developed a protocol to anchor interconnected fibrils of iron oxyhydroxides, using Mn^(2+) as a morphology regulator. The protocol was based on a microwave-assisted hydrothermal method, using bituminous based activated carbon and both Fe^(2+) and Mn^(2+) ions in the hydrolysis solution. The elemental analysis of modified carbons revealed that Mn does not anchor to the carbon. However, when Mn is included in the hydrolysis solution, the iron content in the activated carbon increased up to 3.5 wt%,without considerable decreasing the adsorbent surface area. Under specific hydrothermal conditions, the Mn^(2+) promoted the formation of iron oxide nanoparticles shaped as interconnected fibrils. This material showed a superior arsenic adsorption capacity in comparison to similar iron modified activated carbons(5 mg As/g carbon, at 2 mg As/L),attributed to the increase in quantity and availability of active sites located on the novel interconnected fibrils of iron oxyhydroxides nanostructures.

关键词： Iron oxide nanostructures Hydrothermal synthesis Microwave Adsorption capacity Kinetics

Investigation of the transformation of organic matter of carbonate deposits of the Semiluksky-Mendymsky horizon under hydrothermal conditions

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Petroleum 2024年第2期10卷 216-223页

作者： S.M.Petrov A.I.Lakhova E.G.Moiseeva A.G.Safiulina institute of Petroleum Chemistry and NanotechnologiesKazan National Research Technological UniversityKazan420015Russia institute of Geology and oil and Gas Technologies Kazan Federal UniversityKazan420008Russia

The paper presents the results of studies on the transformation of the organic matter of siliceous-clayey carbonate rocks of the Semiluksko-Mendymsky horizon of the Romashkino oil field in a hydrothermal fluid for an hour(with a water-to-rock ratio of 33)at 340℃and 380℃and pressu res of 17 and 20 *** a result of hydrothermal treatment,at 340℃and 17 MPa,based on nitrogen porosimetry and electron microscopy data,transformations of rock-forming minerals in the rock are *** lead to an increase in the volume and average diameter of mesopores in it and the formation of micropores,as well,which improve its filtration *** the same time,the amount of kerogen in the composition of the organic matter decreases and the yield of the petroleum hydrocarbon extract increases,in which,according to the SARA analysis,the content of asphaltenes increases and the content of resins,aromatic and saturated hydrocarbons *** the composition of aroatic hydrocarbons,the proportion of a lkyltri methyl benzenes and dibenzothiophenes increases,phenanthrene homologues appear,and in the composition of saturated hydrocarbons,the amount of iso-structure alkanes decreases relative to the content of linear *** the temperature and pressure of the hydrothermal fluid to 380℃and 20 MPa increases the degree of kerogen conversion from 12.4%to 23.6%.At the same time,changes occurring in the component composition of petroleum hydrocarbon extracts remains similar to the experiments carried out at 340℃and 17 MPa;the content of naphthalenes decreases,the content of dibenzothiophenes increases and C_(11)-C_(17),C_(19)-C_(22)alkyltrimethylbenzenes *** to IR spectroscopy,with increasing temperature and pressure of the hydrothermal fluid the intensity of the absorption bands of the aromatic ring,aliphatic fragments,and oxygen-containing groups increases in resins;the structural-group composition of asphaltenes changes little:aromaticity and the content of conde

关键词： Carbonate deposits Organic matter Hydrothermal fluid Mobile hydrocarbons

Recent progress in the structure optimization and development of proton-conducting electrolyte materials for low-temperature solid oxide cells

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 848-869页

作者： Jia Song Yuvraj Y.Birdja Deepak Pant Zhiyuan Chen Jan Vaes Separation and Conversion Technology Flemish Institute for Technological Research(VITO)Mol 2400Belgium

This work reviews technologies that can be used to develop low-temperature solid oxide cells(LT-SOCs)and can be applied in fuel cells and electrolyzers operating at temperatures below 500℃,thus providing a more cost-effective alternative than conventional high-temperature *** routes showing potential to reduce the operating temperature of SOCs to below 500℃ are *** first route is the principal way to enhance cell performance,namely,structure *** technique includes the reduction of electrolyte thickness to the nanometer scale and the exploration of electrode structure with low polarization *** other route is the development of novel protonconducting electrolyte materials,which is in the frontier of SOCs *** fundamentals of proton conduction and the design principles of commonly used electrolyte materials are briefly *** most widely studied electrolyte materials for LT-SOCs,namely,perovskitetype BaCeO_(3) -and BaZrO_(3) -based oxides,and the effect of doping on the physical-chemical properties of these oxide materials are summarized.

关键词： low-temperature solid oxide cells perovskite doping thin-film

Entrance Effects in Microchannel Gas Flow

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Journal of Thermal Science 2009年第4期18卷 345-352页

作者： T.Lewandowski S.Jebauer J.Czerwinska P.Doerffer institute of Fluid Flow Machinery Polish Academy of Science institute of Fundamental technological research Polish Academy of Science

Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For thatpurpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions whichrise in such configuration are related to the existence of optimal size of the holes and the influence of microscalephenomena on the global flow patterns. This paper concentrates on the issue of the entrance effects on the microchannelflow. It is shown that mass flow rate is only insignificantly influenced by slip effects. Global parameterssuch as pressure difference and geometrical shape in more pronounced way alter flow behavior. In this paper weconcentrate on the numerical investigation of the microchannel flow for Kn < 0.01 and Re < 500. The channellength is finite. Hence, entrance and outlet effects on microchannel flow can be studied.

关键词： perforated plates microchanneis gas flow simulations

Preparation of Dy-Fe Alloy from Dy2O3 Bymolten Salt Electrochemical Process

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Journal of Rare Earths 2004年第Z1期22卷 332-334页

作者： Lin Jirong Han Fujun Zhao Liangzhong Zhang Xiuyan Zhao Fei research institute for Rare Earth Application technological Baotou 014010 China Research Institute for Rare Earth Application Technological Baotou 014010 China Baotou Huali Rare Earth Co. Ltd.Baotou 014030 China Research Institute for Rare Earth Application Technological Baotou 014010 China Research Institute for Rare Earth Application Technological Baotou 014010 China

Dy-Fe alloy replace dysprosium in the NdFeB permanent material can improve the performance and productivity and cut the *** electrolyte is a binary system of molten *** is cathode and graphite is *** raw material is Dy2O3 *** content of dysprosium is (78 ～85 ) ± 1% in the Dy-Fe alloy made by electrolyzing in the industry *** the course of electrolyzing the efficiency of current, the alloy formation and the productivity of rare earths by studying the formation of electrolyte, the electrolyzing temperature, the standards and the current density of cathode, the anode shape etc were *** conclusion is that we can produce Dy-Fe alloy (the content of dysprosium is (78 ～ 85 ) ± 1% ) in this condition, the efficiency of current is greater than 68 %, and the productivity of rare earth is greater than 92%.The content of oxygen, calcium, wolfram is smaller than the content by reducing.

关键词： electrolyze Dy-Fe alloys experiment rate earths

Insights on the solubilization products after combined alkaline and ultrasonic pre-treatment of sewage sludge

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Journal of Environmental Sciences 2015年第3期27卷 97-105页

作者： Xinbo Tian Chong Wang Antoine Prandota Trzcinski Leonard Lin Wun Jern Ng Advanced Environmental Biotechnology Centre Nanyang Environment and Water Research Institute Nanyang Technological University School of Civil and Environmental Engineering Nanyang Technological University Public Utilities Board Water Reclamation (Plants) Department Nanyang Environment and Water research institute Nanyang Technological University

This work provides insights on the solubilization products after a simultaneous combination of alkaline and ultrasonic （ALK ＋ ULS） pre-treatment of sewage sludge. Soluble chemical oxygen demand （SCOD） increased from 1200 to 11,000 mg/L after such treatment. Organics with molecular weight around 5.6 kDa were solubilized because of the synergistic effect of ultrasound and alkali. Organics with molecular weight larger than 300 kDa increased from 7.8% to 60%, 16% and 42.3% after ULS, ALK and ALK ＋ ULS treatment, respectively. Excitation emission matrix fluorescence spectroscopy analysis identified soluble microbial product-like and humic acid-like matters as the main solubilization products. Sludge anaerobic biodegradability was significantly enhanced with the simultaneous application of ALK ＋ ULS pre-treatment. ALK ＋ ULS pre-treatment resulted in 37.8% biodegradability increase compared to the untreated sludge. This value was higher compared to the biodegradability increase induced by individual ALK pre-treatment （5.7%） or individual ULS pre-treatment （20.7%） under the same conditions applied.

关键词： Ultrasound AlkaliSewage sludge Molecular weight Excitation emission matrix (EEM) Anaerobic biodegradability