Engineering Science and Materials Commons^™

Mode-I Toughness And Curing Pressure Characterisitc Of Symmetrical Lay-Up Of Plain Weave Woven Gfrp Composites, Mohd Aidy Faizal Johari, Kiam Beng Yeo, Mohd Noh Dalimin

mohd aidy faizal johari

This study describes an experimental study on the interlaminar Mode-I fracture toughness behavior of hand lay-up plain-weave woven GFRP laminate by using a fracture energy method of evaluation. Mode-I double cantilever beam (DCB) tests were performed on woven GFRP unsaturated polyester composite, E-Glass EWR 600 NISER, specimens. The specimen design and test procedure are performed with reference to the BS ISO 15024 and ASTM D5528. Various curing uniform pressure distribution has been investigated at 35.8kg/m2, 70.1kg/m2, 104kg/m2 and 138.2kg/m2, with respect to the toughness value. The lay-up laminates designed with symmetrical arrangement at the center-plane of the composite are also …

Forest Products Laboratory: Supporting The Nation's Armed Forces With Valuable Wood Research For 90 Years, Christopher D. Risbrudt, Robert J. Ross, Julie J. Blankenburg, Charles A. Nelson

Julie Blankenburg

Founded in 1910 by the U.S. Forest Service to serve as a centralized, national wood research laboratory, the USDA Forest Products Laboratory (FPL) has a long history of providing technical services to other government agencies, including those within the Department of Defense (DoD). A recent search of FPL’s library and correspondence files revealed that approximately 10,000 articles, reports, manuals, other technical publications, and communications have been generated and provided to the DoD since 1910. FPL has provided support on a broad array of technical questions—from designporting materiel to Europe and the South Pacific during World War II to assisting in …

Selective Removal Of Heavy Metals From Metal-Bearing Wastewater In A Cascade Line Reactor, Zeljko J. Kamberovic

Zeljko J Kamberovic

This paper is a part of the research work on 'Integrated treatment of industrial wastes towards prevention of regional water resources contamination – INTREAT' the project. It addresses the environmental pollution problems associated with solid and liquid waste/effluents produced by sulfide ore mining and metallurgical activities in the Copper Mining and Smelting Complex Bor (RTB-BOR), Serbia. However, since the minimum solubility for the different metals usually found in the polluted water occurs at different pH values and the hydroxide precipitates are amphoteric in nature, selective removal of mixed metals could be achieved as the multiple stage precipitation. For this reason, …

Sintering Of Cu–Al2o3 Nano-Composite Powders Produced By A Thermochemical Route, Zeljko J. Kamberovic

Zeljko J Kamberovic

This paper presents the synthesis of nano-composite Cu–Al2O3 powder by a thermochemical method and sintering, with a comparative analysis of the mechanical and electrical properties of the obtained solid samples. Nano-crystalline Cu–Al2O3 powders were produced by a thermochemical method through the following stages: spray-drying, oxidation of the precursor powder, reduction by hydrogen and homogenization. Characterization of powders included analytical electron microscopy (AEM) coupled with energy dispersive spectroscopy (EDS), differenttial thermal and thermogravimetric (DTA–TGA) analysis and X-ray diffraction (XRD) analysis. The size of the produced powders was 20–50 nm, with a noticeable presence of agglomerates. The composite powders were characterized by …

Synthesis And Sintering Of Cu-Al2o3 Nanocomposite Powders Produced By A Thermochemical Route, Zeljko J. Kamberovic

Zeljko J Kamberovic

By hydrometallurgy and powder metallurgy along with prognosis of physical- chemical properties, a synthesis of new improved materials can be successfully performed with in advance pre-set properties which is conditioned by a quality of starting powders i.e. by improving their structure. In accordance with that, this paper presents synthesis of the nanocomposite Cu-Al2O3 powder by thermochemical method and sintering with a comparative analysis of the mechanical and electrical properties of obtained solid samples. Nanocrystaline Cu-Al2O3 powders were produced by thermochemical method through following stages: spray-drying, oxidation of precursor powder, reduction by hydrogen and homogenisation. Characterization of powders included differential-thermal and …

Bubble Electrospinning For Mass Production Of Nanofibers, Yong Liu, Ji-Huan He

Ji-Huan He

A new bottom-up gas-jet electrospinning process for mass production is presented. A bubble-induced cone on the surface of polymer solution is equivalent to the Taylor cone in traditional electrospinning, which is a must for producing nanofibers. In this study bubbles are produced by compressed air or nitrogen through a nozzle settled in the bottom of the solution. Multiple jets are observed during the electrospinning process as predicted for it is easy to many bubble-induced cones on the solution surface. The new electrospinning mechanism can be used for mass production of nanofibers.

Modification Of Multi-Walled Carbon Nanotubes By Microwave Digestion Method As Electrocatalyst Supports For Direct Methanol Fuel Cell Applications, Fang-Tzu Chuang

Fang-Tzu Chuang

Multi-walled carbon nanotubes (MWCNTs) which were directly synthesized on carbon cloth were modified by a microwave digestion method in 5M HNO3 for supporting Pt nanoparticles. The characterizations of modified CNTs were carried out by TEM, XPS, FTIR and Raman spectroscopy. The HRTEM image shows the caps of MWCNTs are opened after modifying by microwave digestion method. The open-end and undamaged MWCNTs can provide a larger surface area for supporting more catalysts. Furthermore, the methanol electrocatalytic oxidation of microwave digestion treated Pt/MWCNTs electrode shows higher current density than pristine and nitric acid-treated MWCNTs from cyclic voltammograms. This can be an effective …

Study Of Chemical Surface Modifications Of Cnts As Cathode Electrode For Dmfc, Fang-Tzu Chuang

Fang-Tzu Chuang

In this study, multi-wall carbon nanotubes (MWNTs) are used as Pt catalyst support for cathode electrode in the direct methanol fuel cell (DMFC). Thus, a lot of well-align MWNTs are fabricated on carbon cloth directly. The method in the cathode electrode of DMFC is easy to constructed and sticking on the carbon cloth tightly. Then, MWNTs are modified by HNO3, H2SO4, and KOH at high temperature may produce different functional groups to attract more Pt ions nucleating uniformly and densely. Moreover, there are the other parameters, temperature, time, and concentration, in the function of chemical modification for MWNTs. In this …

Fabrication Of Pdms (Polydimethylsiloxane) Microlens And Diffuser Using Replica Molding, Fang-Tzu Chuang

Fang-Tzu Chuang

This paper reports the fabrication method of PDMS (polydimethylsiloxane) microlens array based on the replica molding process, casting a liquid PDMS into concave microlens molds. Concave microlens molds were fabricated through spin-coating processes suspended a liquid PMMA film on the micro-drilled hole, leading to the formation of the special curvature. Then, PDMS microlens arrays and diffusers were fabricated by replica molding and discussed in this study. The fabricated microlenses have both good surface roughness and high-quality optical properties. Therefore, diffusers were fabricated by two-step replica molding. A high-intensity He–Ne laser beam was uniformly spread through diffusers. Experimental tests demonstrated that …

Study Of Leading Factors In Formation Of Surface Wavy Structures On A Rubber Material, Fang-Tzu Chuang

Fang-Tzu Chuang

Wavy structures are often observed on the surface of a rubber material (polydimethylsiloxane, PDMS) covered with a thin metallic film. In this study we demonstrate that the orientation, periodicity, location of formation, and range of periodicity of the wavy structures can be regulated by three leading factors including the surface pattern, substrate hardness and the thickness of the metallic film. Results show the orientation of the wavy structures can be adjusted by the location, shape and size of the surface patterns. Enhancement of the substrate hardness can prevent forming random wavy structures. The thickness of surface metallic film significantly influenced …

The Synthesis Of Ultrafine And Nanocomposite Powders Based On Copper, Silver And Alumina, Zeljko J. Kamberovic

Zeljko J Kamberovic

Contemporary materials with predetermined properties can be successfully synthesized by utilising the principles of hydrometallurgy and powder metallurgy. The results of developing a new procedure for the synthesis of ultrafine and nanocomposite powders based on copper, silver and alumina are presented in this paper. A two-component nanocomposite powder, Cu-Al2O3, was synthesized by a thermochemical procedure, by deposition from an aqueous solution of soluble metal salts, Cu(NO3)2 and Al(NO3)3. A three-component Cu-Ag-Al2O3 powder was produced by mechanically alloying nanocomposite Cu-Al2O3 powder and Cu-Ag powder, synthesized by the thermochemical procedure. The produced powders were characterized by determining the particle specific area, pouring …

30 Adet Pantone Rengin Ink Formulation Programi Kullanilarak Hazirlanmasi, Bilge N. Altay, Nazli Burcu Taklak

Bilge Nazli Altay

Fabrication Of Various Curved Relief Structures Through Concave Surface Forming And Soft Replica Molding, Fang-Tzu Chuang

Fang-Tzu Chuang

In this case, our groups presented various optical structures through the presented method, involving concave surface forming and soft replica molding. The method of concave surface forming is mainly for the fabrication of concave surface. The method of soft replica molding is mainly for the fabrication of replica. Concave and convex relief structures, including circular curved relief structures, convex relief structures with platform structures on the top, refractive beam-shaping elements, these structures with dual curvatures and asymmetric structures, can be easily made through the presented method, respectively. All processes of manufacture are in several simple steps without multistep optical lithography …

The Influence Of Titanium And Cerium On Microstructure And Properties Of Fe-C-Cr-Nb Alloys, Zeljko J. Kamberovic

Zeljko J Kamberovic

In this paper, the influence of titanium and cerium on the microstructure and properties of Fe- C-Cr-Nb alloys are examined, in both as-cast and heat treated state. These elements affect the crystallisation process of Fe-C-Cr-Nb alloys and the transformation of austenite during the cooling process after solidification. Titanium changed the morphology of NbC carbides. Further, in the austenite of the examined Fe-C-Cr-Nb-Ti alloys, very fine particles of precipitated secondary carbide can be seen. The alloy containing 0,28%Ti and 0,19%Ce has martensite-perlite-austenitic matrix microstructure in as-cast condition. Adding titanium and cerium to Fe-C-Cr-Nb alloys will also changed its properties, since the …

Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

Surface Structure Of Alkylsilylated Hzsm-5 As Phase-Boundary Catalyst, Hadi Nur, Yun Hau Ng, Mohd Nazlan Mohd Muhid, Halimaton Hamdan

Yun Hau Ng

The need for cleaner environment concerns motivates the development of more efficient catalytic system. Based on this consideration, recently a novel catalyst named "Phase-boundary catalyst", a bimodal amphiphilic solid catalyst, was proposed. It was demonstrated that the catalytic system containing phase-boundary catalyst required neither stirring to make an emulsion nor addition of a co-solvent to make a homogeneous solution to drive the reaction. The driving force that has prompted this paper is to investigate the surface structure of alkylsilylated HZSM-5 as phase-boundary catalyst. Temperature Programmed Desorption (TPD) of ammonia and, 13C and 29Si MAS NMR spectroscopy were used to elucidate …

Possibilities Of Recycling Of Magnesium And Magnesium Alloys, Zeljko J. Kamberovic

Zeljko J Kamberovic

In this paper are presented results of experimental investigation of processing of non oil-contaminated metal scrap based on magnesium and its alloys. These are the firs investigations of magnesium scrap recycling in Serbia and Montenegro. Experimental investigations were conducted in laboratory scale and achieved results were verified in industrial scale (Magnesium factory ″Bela Stena″ in Baljevac on Ibar). Experiments included following the influence of preparation of metal scrap on metal extraction efficiency rate.

Development Of Contemporary Procedures For Lead Obtaining, Zeljko J. Kamberovic

Zeljko J Kamberovic

Contemporary procedures of lead concentrates treatment were in different expansion during last thirty years. All procedures have in common the following: smelting reaction proceeds in solid-gas suspension, melting products are metallic lead and slag, which are leaving electric furnace together. The conditions for production metallic lead and slag in one furnace are determined using thermodynamic analysis of contemporary direct smelting procedures. The characteristics and progress of direct smelting process are determined using oxygen/concentrate ratio, which influences the lead content in slag, sulphur content in bullion and the following metals distribution. The KIVCET and Boliden TBRC are contemporary procedures that found …

Optimisation Of Ferriferous Dust And Mud Preparation Acts From Iron And Steel Production On Purpose Of Returning To Primary Processes, Zeljko J. Kamberovic

Zeljko J Kamberovic

In this paper detailed characterization of ferriferous dust and mud which originated from aglomerization, blast- furnace and converter process in Iron-works Smederevo were shown. Optimization of method peletization was conducted in variably conditions (different moinsture content, changing of time of peletization and type of binder). These palets were submitted to examination of resistance on impact and pressure, and their behavior was confirmed returning in sintering process in semiindustrial conditions. Ideally-technological solution for plant preparation of dust and mud in Iron-works Smederevo was recommanded. That solution should contribute to improvement of techno-economic parametars of aglomeration and blast- furnace process, as well …

Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi

Fathi Habashi

An advice, the old wise man Polonius offered to the young Hamlet was “Neither a borrower, nor a lender be”, may be no longer pertinent. Some more relevant advices are offered to new graduates of the twentieth century. Available in English, French, and Spanish

On The Physicochemical Problems Of Aqueous Oxidation Of Polymetallic Gold Bearing Sulphide Ore In An Autoclave, Zeljko J. Kamberovic

Zeljko J Kamberovic

The paper presents a study on the physical and chemical changes of iron, copper and zinc sulphide minerals in process of pressure oxidation. Oxidation in autoclave is a pre-treatment unit operation for refractory sulphide ores and concentrates in order to valorisat gold, which is encapsuled mainly in pyrite matrix. Raw materials and solid residues are charasterisated. Basing on the results of chemical reactions and on shape of solids residue, we came to a conclusion concerning the mechanism of oxidation in autoclave. The results show that modelling of the process parameters of oxidation in autoclave can be used to predict efficiency …

Leaching Of Copper(I) Sulphide By Sulphuric Acid Solution With Addition Of Sodium Nitrate, Zeljko J. Kamberovic

Zeljko J Kamberovic

Finely grained samples of copper(I) sulphide were leached by H2SO4 solution with added NaNO3. The occurrence probability of chemical reactions was analysed based on literature data and products which were formed during the process and the overall leaching reaction was defined. The effect of temperature, concentration of NaNO3 and H2SO4, stirring speed, phase ratio and time, on the leaching degree of copper was studied. The quantity of copper dissolved increases with growth of the values of all the parameters. Kinetic analysis shows that the leaching mechanism is very complex. By using appropriate mathematical kinetic models, it is found that the …

From Alchemy To Atomic Bombs. Book Review By George Kauffman, Fathi Habashi

Fathi Habashi

Review of the book "From Alchemy to Atomic Bombs" by Fathi Habashi published by Métallurgie Extractive Québec. The review is written by Professor George Kauffman at California State University, Fresno.

Study Of Chlorination Of Nickel Ferrite By Gaseous Chlorine And Calcium Chloride In The Presence Of Active Additives, Zeljko J. Kamberovic

Zeljko J Kamberovic

Thermodynamic analysis and experimental research of the chlorination of nickel ferrite (NiFe2O4) by gaseous chlorine in the presence of added C, BaS, S and NaCl in the temperature range from 300 to 900¾C are given in this paper. Nickel ferrite chlorination in the presence of BaS and CaCl2 was carried out in the temperature range from 750 to 950¾C. The presence of added C, BaS, S and NaCl intensifies the chlorination process of nickel ferrite by gaseous chlorine and reduces the temperature the reaction begins at from 700 to 300¾C. It is concluded that the process of nickel chlorination without …

Study Of Chlorination Of Nickel Silicate By Gaseous Chlorine And Calcium Chloride In The Presence Of Active Additives, Zeljko J. Kamberovic

Zeljko J Kamberovic

The paper presents a thermodynamic analysis and experimental research on the kinetics of the chlorination of nickel silicate (2NiOÀSiO2) by gaseous chlorine and calcium chloride without additives and in the presence of added C, BaS, S and NaCl, to intensify the process. The influence of temperature in the range from 673 up to 1223 K for various chlorination times has been studied. Additives increases the chlorination rate. The kinetics of the process were determined by the analysis of dependence of the nickel chlorination rate on time and temperature. It was established that nickel chlorination without additives is a chemically-controlled reaction, …

A Memorable Meeting, February 1994, Fathi Habashi

Fathi Habashi

Decision taken at the Steering Committee Meeting of the International Mineral Processing Congress in San Francisco February 1994 to name the IMPC Award.

Hidrometalurjide Yeni, Fathi Habashi

Fathi Habashi

Turkish translation of F. Habashi, “Recent Advances in Hydrometallurgy,” Proceedings International Mineral Processing Congress, Warsaw, 1979, edited by J. Laskowski, published by Elsevier, pp. 902–935

Progress In Extractive Metallurgy, Volume 1. Review By G.N. Dobrokhotov, Fathi Habashi

Fathi Habashi

Review of the first volume of Progress in Extractive Metallurgy edited by Fathi Habashi and published by Gordon & Breach in New York in 1975. The review was written by Professor Dobrokhotov at the Leningrad Mining Institute.