bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Changing the Vapor Flux on Physical Properties of Nanocrystaline CdTe Thin Film, Prepared by Thermal Evaporation Method
Authors: Hosseini Siyanaki Fatemeh , Dizaji Hamid Rezagholipour , Ehsani Mohammad Hosein , Khorramabadi Shiva
Published: November 2013

In the present investigation, seven Cadmium Telluride (CdTe) thin films with thickness of 350nm have been prepared by vacuum thermal evaporation technique. One of them was deposited by conventional vacuum thermal evaporation technique, while six others were deposited with applying a novel vapor flow controlling system. Placing this equipment in the way of vapor flux from the source to the substrate cut the depositing flux of vapor periodically and can change the way of vapor flux. It led to considerable change of optical properties, nanocrystalline structure, and also stochiometery of the thin films. All the samples showed nanocrystalline structure. A considerable increase in absorption coefficient was observed at 520nm wavelength of light, from 5.5 ×104cm-1for the sample prepared with conventional vacuum thermal evaporation technique to 9.8×104cm-1for a sample which prepared by applying mentioned equipment. The most considerable change in the bandgap, grain size and Te/Cd ratio were 1.54 eV to 1.66 eV, 40nm to 15nm, and 56/44 to 60/40 respectively. The optical parameters such as absorption coefficient, bandgap, refractive index, and structural parameters such as texture coefficient, preferential orientation factor and crystallite size of samples were obtained. Also EDAX and FESEM result of samples were compared with each other in this study.
Interfacial Examination of Cu/Al Joints Using Ultrafine Al-Si Powder as Brazing Filler Metal
Authors: Yarveicy Maryam , Hadian Ali Mohammad
Published: November 2013

Al-Cu joints have been widely used in electronic and heat exchanger industries due to their excellent electrical and thermal conductivity. Meanwhile, the use of Al in the Al-Cu joints can result in lower weight and cost of the final structure. The purpose of the current study is to join Al to Cu by furnace brazing using ultrafine Al-Si powder. To study the microstructure of the join area, the brazing tests were conducted in the range of 590 to 610°C for 5 to 15 minutes under inert atmosphere. The microstructure of Al/Cu joints was studied by scanning electron microscopy (SEM). The elemental analysis was conducted using an energy dispersive spectrometry (EDS) system. Experimental results show that two kinds of intermetallic compounds (IMCs) mainly Cu3Al2 and CuAl2 phases are formed near the interface of copper and in the braze layer region. The bulky prismatic structure which is formed on the side of Al substrate was found to be α-Al+CuAl2 eutectic.
Synthesis of Nickel/Ba-Hexaferrite Magnetic Nano-Composite via Mechanical Alloying Route
Authors: Sobhani Issa , Ataie Abolghasem , Ijavi Mahdiye , Sadighi Zoya
Published: November 2013

In this study, nickel and Ba-hexaferrite powders were subjected to high energy mechanical milling in argon atmosphere to produce nickel/Ba-hexaferrite magnetic nanocomposite. Effects of milling time and Ni amount on the phase evolution, morphology and magnetic properties of the products have been investigated by XRD, FESEM/SEM and VSM, respectively. XRD analysis of nanocomposite indicated only Ni peaks after 5 h milling which implied the embedding of Ba-hexaferrite particles inside the metallic nickel. FESEM results revealed that the increasing of the milling time up to 30 h reduced nanocomposite particles size into 20 nm. VSM results showed that the magnetic properties of the nickel/Ba-hexaferrite nanocomposite were affected by the process conditions. The highest saturation magnetization (33.8emu/g) was obtained for the sample containing 30 wt% Ni milled for 20 h Ni series of powder mixture. In addition, it was found that by increasing the milling time coercive field decreases.
Preparation of NiO-Ni Nanocomposite by Using of Glutaric Acid in Neutral Condition
Authors: Rahimipour Hamid Reza , Hosseinian Akram
Published: November 2013

NiO-Ni nanocomposite was synthesized by a conventional sol-gel process. Ni-NiO nanocomposite has been fabricated via the thermal decomposition of nickel salts by using glutaric acid as a spacer agent. A possible mechanism was showed which proposed an optimum temperature to remove nickel impurity from composite in calcinations of nickel glutarate. The produced nanoparticles through the thermal decomposition process were characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM). The chemical structure of the products was studied by Fourier transform infrared (FT-IR) spectroscopy. The mean crystallite size of the obtained nanosized was estimated to be in the range of 22 nm to 41 nm. The thermal behavior of compound was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).
Growth of Carbon Nanotube on the Ni-Mesoporous Alumina Catalysts for Use as Adsorbent
Authors: Shahbazi Pariya , Kazemzad Mahmood , Yuzbashi Amirali
Published: November 2013

Ordered mesoporous materials with high specific surface area and large pore volume have high potential for commercial applications in adsorption and catalysis. In this study, ordered mesoporous alumina (γ-alumina) with high thermal and chemical resistance was synthesized by the sol-gel method using various organic compounds, i.e. aminoacids and carboxylic acids as template. The obtained data showed that γ-Al2O3 produced in the presence of carboxylic acids as template results in very well catalytic activities for CNT growth. The best results obtained using Ni catalysts supported on alumina at a temperature of 900 °C. Since the method and amount of the catalyst deposited on a porous support affects its efficiency in CVD growth of CNT, the above parameters have been also optimized in this work. Alumina supported CNT,s were applied as adsorbent for removal of some organic compounds from aqueous samples. The microstructure, morphology, and chemical composition of the adsorbents were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). Efficiency of synthesized samples for adsorption organic compounds was investigated by high performance liquid chromatography (HPLC) analysis of filtrate. This work showed that, although mesoporous alumina supported CNT can be applied as a good adsorbent for removal of trace amounts of organic compounds from drinking water efficiency of the adsorbents are extremely dependent on the porous adsorbent syntheses condition.
Production of Cu-TiC Nanocomposite Using Mechanical Alloying Route
Authors: Bagheri G. Ali , Abachi Parvin , Purazrang Kazem , Rostami Abbas
Published: November 2013

In this study, Cu-TiC nanocomposites were produced by high energy ball milling of elemental powders and in-situ formation of TiC in the copper matrix. Cu-40wt% Ti powder mixture were milled for 60 h, then graphite powder was added, subsequently milling was continued for further 10 h. Based on theoretical calculations, at this composite, the amount of TiC as reinforcement should be 60.25vol% (45.47wt%). The effect of milling time on solution progress of titanium in the copper lattice was studied by X-Ray diffraction analysis (XRD) with CuKα radiation. Considering XRD of Cu-40wt%TiC after 60 h milling data and Williamson-Hall relation, crystallite size and lattice strain of copper were determined 12nm and 1.04% respectively. To ensure the formation of titanium carbide, XRD analysis was performed after pressing at 300MPa and sintering at 900oC for an hour and heating rate of 2.5oC/min. XRD pattern was indicated the formation of TiC,CuTi3and TiO2phases in Cu matrix.
The Effects of Reduced Graphene Oxide (rGO) on ZnO Film UV-Detector
Authors: Safa Saeed , Sarraf-Mamoori Rasoul , Azimirad Rouhollah
Published: November 2013

In this work, pure and graphene incorporated ZnO thin films were prepared by solgel method on glass substrates and influence of graphene doping on the structural, electrical and optical properties of the films were studied. The results of Raman spectrum indicated the coexistence of ZnO and rGO in composite thin film. The FT-IR analysis of the composite sample showed that ZnO, ZnO-C heterojunction and C-C graphene skeletal peak are formed. The UV-Vis spectrum showed that both the transparency and band gap was partially decreased by graphene incorporation. The linear trend of I-V curve suggests an ohmic contact between ZnO and graphene nanosheets. In addition, the resistivity was decreased from 4.32×102 Ω.cm for pure ZnO film to 2.4×101 Ω.cm for composite film. The composite photodetector possessed a desirable signal to noise ratio and UV-sensitivity while the response time decreased to half of pure ZnO. The above results suggest that 0.225 wt.% rGO incorporation can improve the ultraviolet detection of ZnO thin film.
Investigation of Microbial Cellulose/Cotton/Silver Nanobiocomposite as a Modern Wound Dressing
Authors: Khajavi Ramin , Meftahi Amin , Alibakhshi Somayeh , Samih Leila
Published: November 2013

In this study the nanobiocomposite of Microbial cellulose/Cotton/Silver is introduced as a modern wound dressing. Microbial cellulose was synthesized in situ on cotton gauze. The static medium culture (Hestrin & Scharm) and Acetobacter Xylinum used for microbial cellulose synthesis and 6 days formed layers used for experiments. Half of 6 days samples were reverse after 3 days in order to form double coated gauze. One or two coated sides specimens were deactivated purified and dipped in a 500ppm nanosilver concentration. Specimens were analyzed by X-ray diffraction method, Fourier transform infra-red spectroscopy, Scanning electron microscopy and transmission electron microscopy. Their water and moisture absorption determined and their antibacterial efficiency evaluated by AATCC 100 antibacterial test method. Results showed about 30% increase in water absorption with less than 8% moisture regain. Microscopic images showed a proper distribution of nanosilver without agglomerations at surface and inside nanobiocomposite which caused improved antimicrobial efficiency. The obtained results indicated that nanocomposite (double coated gauze) has high potential for applying as a modern wound dressing.
Effect of Heat Treatment on Mechanical Properties of ECAPed 7075 Aluminum Alloy
Authors: Fallahi Alireza , Hosseini-Toudeshky Hossein , Ghalehbandi Seyed Mahmoud
Published: November 2013

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.
Synthesis and Modification of SAPO-34 Nanoparticles by Incorporation of Metal Ions Using Rapid High Temperature Method
Authors: Dadjoo Mohammad Hasan , Halladj Rouein , Askari Sima , Jalili Shadi
Published: November 2013

Considering studies done on the result of methanol conversion over SAP-34 molecular sieve, it is understood that increase of selectivity is ascribed to the increase of acidity in acid sites which is a result of incorporation of metal in crystal structure and decrease of crystal size. In this study, metal incorporation in the SAPO-34 structure leaded to increase of acid sites concentration but did not affect the acid strength distribution. The catalytic performance of the SAPO-34 nanoparticles in the MTO reaction varied according to their crystallite size. Decreasing particle size results in larger increase of external surface area and shorter diffusion path, both cause reduction in mass and heat transfer resistances in catalysis and sorption. In this work a rapid high-temperature synthesis method was developed to synthesis uniform nanoparticles of SAPO 34 zeolite with high crystallinity and metal was successfully incorporated in crystal structure. In order to investigate the effects of temperature and synthesis time on purity and crystallinity of the synthesized samples, the crystallization temperature was increased from 350 to 550 K while the synthesis time was decreased from 24 h to 45 min. The samples were characterized by XRD, BET and SEM analysis techniques. It was found that by using high temperature and short synthesis time the particle size decreased and the metal was properly incorporated into the crystal structure.
Investigation of Nanoparticles of Carbon and Calcined Alumina on Mechanical and Corrosion Properties in MgO-C Refractories
Authors: Faghih Mojdeh , Karamian Ebrahim , Monshi Ahmad
Published: November 2013

Today due to the unique properties of magnesia carbon refractories, the iron and steel industries are of special interest. Therefore, it is important to extend the life of the refractory. The effect of calcined alumina and nanocarbon on the mechanical strength and corrosion resistance against slag refractories magnesia carbon has been studied. Mechanical strength of cold crushing strength (CCS) was measured according to ASTM C0133-97R03 numbers. The bulk density (BD) and apparent porosity (AP) were determined respectively, relative to the size and weight measured using Archimedes method according to ASTM C0020-00R05 numbers and corrosion resistance against slag shrub procedure. Samples prepared at cylinder 50×50 mm were tempered on 250 °C for three hours. The corrosion resistance of the samples cocked on 1350 °C for two hours under reducing atmosphere (coke bed) was evaluated. During the review process of characterization methods, XRD, SEM-EDX has been used. The results showed that the properties improved.
The Effect of Heat Treatment on the Magnetic Properties of Nanocrystalline Fe-Ni-Si Powders
Authors: Foroughi Paniz , Moghadasi Mohammadamin
Published: November 2013

This paper investigates the effect of heat treatment on the magnetic properties of nanocrystalline Fe-Ni-Si powders prepared by mechanical alloying method which can be used in soft magnetic composites fabrication. Fe-85%, Si-10% and Ni-5% alloys were prepared using a vibrating disc mill. The magnetic properties of the samples were measured by a vibrating sample magnetometer (VSM) and the microstructural properties of the un annealed sample were measured by XRD and SEM. Three samples were annealed in three different temperatures from 500 °C to 600 °C and were compared with a sample without annealing. It was found that with increasing the annealing temperature, stress relieving and crystallite size increased whereas microstrain and saturation magnetization decreased.
Investigation on Phase Evolution in Mechanically Alloyed Nano-Structured Fe-Si System
Authors: Torkan Sara , Ataie Abolghasem , Abdizadeh Hossein
Published: November 2013

In the present research, nano-crystalline Fe­70Si30alloy powders were prepared by mechanical alloying using Fe and Si powder as starting materials. Powder samples were taken from the mill at selected time intervals (5, 20, 40, 50, 60, 70h) for the structural properties analysis. The phase composition, morphology and magnetic properties of nano-structured alloy powders were analyzed by XRD, FESEM and VSM techniques, respectively. The evolution of non-equilibrium solid solution Fe (Si) during milling was accompanied by refinement of crystallite size. Dissolution of Si atoms into Fe matrix was also studied. The quantitative analysis of phase composition was carried out using Maud software which is based on the Rietveld method combined with Fourier analysis. XRD results showed a coexistence of BCC, DO3and FeSi structural phases for 40h milled sample, quantity of DO3and FeSi phases decreased for prolonged milling time. These phases disappeared in 60h milled sample and BCC FeSi phase with a mean crystallite and particle sizes of 20 and 70 nm were formed. The results also indicated that by mechanical alloying of the FeSi system for 60h, it was possible to extend the solubility of the BCC FeSi structure to 30 at% Si.
Synthesis of Nanostructured Bismuth Ferrite by Mechano-Thermal Route
Authors: Ahmadzadeh Mostafa , Ataie Abolghasem , Mostafavi Ebrahim
Published: November 2013

In this study, multiferroic BiFeO3 (BFO) powders were synthesized via mechanical activation of Bi2O3 and Fe2O3 with the molar ratio of 1:1, using a planetary high energy ball mill and subsequent heat treatment. All samples were milled for 20 h and heat treated at various temperatures. XRD, FESEM, LPSA, and VSM techniques were used to evaluate the powder particle characteristics. FESEM images of 20 h milled sample indicated plate-like particles with a mean thickness of 45 nm and its LPSA results showed the mean agglomerate size of about 2.0 μm. XRD results of calcined samples showed that the BFO phase began to form at 650 °C and fully formed at 750 °C. In comparison to the conventionally processed samples, BFO phase formation temperature decreases by 100 °C in the samples produced by mechanical activation assisted process. VSM measurements of the sample heat treated at 750 °C revealed a saturation magnetization (Ms) of 0.054 emu/g and coercivity (Hc) of 412 Oe.
Low Temperature Synthesis of Barium Titanate Powder by a Modified Sol-Gel Method
Authors: Yasseri Mohammad , Abdizadeh Hossein , Shakeri Amid , Golobostanfard Mohammad Reza
Published: November 2013

Barium titanate (BT) is one of the most important lead-free ferroelectric materials with perovskite crystal structure and high dielectric constant. Among synthesis techniques of BT, sol-gel processing has attracted considerable interest due to the control of composition, surface morphology engineering, low temperature processing, and low equipment cost. In this research, nanocrystalline BT powders were prepared by a modified sol-gel technique. Acetic acid and water were used as solvents. The samples were heat treated at various temperatures, times, and rates for investigating the effect of heat treatment parameters on formation of single perovskite crystalline phase. According to the results of X-ray diffraction analysis, highly pure BT powder with minimum secondary phases (Magneli) was obtained after calcination at 650 °C for 1 h with the rate of 10 °C/min. The grain size and morphology of BT powders were obtained by field emission scanning electron microscopy which indicated the size of about 60 nm.
Removal of Copper from Industrial Water and Wastewater Using Magnetic Iron Oxide Nanoparticles Modified with Benzotriazole
Authors: Jadidian Reza , Parham Hooshang , Haghtalab Sara , Asrarian Razieh
Published: November 2013

This paper shows effective removal of copper from water and industrial wastewater by modified magnetic nanoparticle with benzotriazole as an efficient adsorbent. The method is fast, simple, cheap, effective and safe for treatment of copper polluted waters. Non-modified magnetic iron oxide nanoparticles (MIONPs) can adsorb up to 49.6% of 50 ng ml-1 of Cu (ΙΙ) ions from polluted water, but modified magnetic nanoparticles improved the efficiency up to 99.7% for same concentration. The required time for complete removal of copper ions was 5 minutes. Variation of pH and high electrolyte concentration (NaCl) of the solution do not have considerable effect on the copper removal efficiency.
Microstructural and Magnetic Properties of Nanostructured Fe65Co35 Powders Prepared by Mechanical Alloying
Authors: Razi Mohsen , Ghasemi Ali , Borhani Gholam Hossein
Published: November 2013

Nanostructured Fe65Co35 alloy powders were fabricated by mechanical alloying in an attritor mill with different milling times. The milling process carried out in speed of 350 rpm, with 20:1 ball to powder weight ratio and under argon protective atmosphere. A continuous cooling system applied to avoid increasing temperature during the milling. The effect of milling time on structural and magnetic properties investigated by X-ray diffraction, scanning electron microscopy and vibration sample magnetometer. According to the obtained results, nanostructured Fe65Co35 solid solution powders resulted with an average particle size of 400 nm and crystallite size of 6.8 nm by milling for 20 hours. With increasing the milling time, the lattice parameter decreased and the lattice strain increased for Fe65Co35 powders. The maximum saturation magnetization with 1311 emu/cc value and the minimum coercivity with 22 Oe value occurs after milling for 15 hours.
Validity of Molecular Dynamics Heat Transfer by Quantum Mechanics
Authors: Prevenslik Thomas
Published: November 2013

MD is commonly used in computational physics to determine the atomic response of nanostructures. MD stands for molecular dynamics. With theoretical basis in statistical mechanics, MD relates the thermal energy of the atom to its momentum by the equipartition theorem. Momenta of atoms are derived by solving Newtons equations with inter-atomic forces derived by Lennard-Jones or L-J potentials. MD implicitly assumes the atom always has heat capacity as otherwise the momenta of the atoms cannot be related to their temperature. In bulk materials, the continuum is simulated by imposing PBC on an ensemble of atoms, the atoms always having heat capacity. PBC stands for periodic boundary conditions. MD simulations of the bulk are therefore valid because atoms in the bulk do indeed have heat capacity. Nanostructures differ. Unlike the continuum, the atom confined in discrete submicron structures is precluded by QM from having the heat capacity necessary to conserve absorbed EM energy by an increase in temperature. QM stands for quantum mechanics and EM for electromagnetic. Quantum corrections of MD solutions that would show the heat capacity of nanostructures vanishes are not performed. What this means is the MD simulations of discrete nanostructures published in the literature not only have no physical meaning, but are knowingly invalid by QM. In the alternative, conservation of absorbed EM energy is proposed to proceed by the creation of QED induced non-thermal EM radiation at the TIR frequency of the nanostructure. QED stands for quantum electrodynamics and TIR for total internal reflection. QED radiation creates excitons (holon and electron pairs) that upon recombination produce EM radiation that charges the nanostructure or is lost to the surroundings a consequence only possible by QM as charge is not created in statistical mechanics. Valid and invalid MD simulations from the literature are illustrated with nanofluids and nanocars, respectively. Finally, valid and invalid MD solutions for the stiffening of NWs in tensile tests are presented to illustrate the unphysical findings if QM is ignored at the nanoscale. NW stands for nanowire.
Experimental Manipulation of Gold Nano-Particles by Atomic Force Microscope and Investigating Effect of Various Working Parameters
Authors: Shahmoradi Zavareh Seyed Abbas , Akbari Moayyer Hamid , Ahouei Mohammad Amin
Published: November 2013

Due to involvement of various fields of engineering and bio researchers in nanoprojects and their need in achieving certain layout of nanoparticles (NPs) in many research studies, considerable attention is paid to nanomanipulation nowadays. The present experimental study employs Atomic Force Microscope (AFM) in order to push gold nanoparticles on a highly flat mica surface. A silicon probe in contact mode is used to both image and manipulate nanoparticles and Topo and L-R images have been obtained to show the successes of manipulation when proper conditions are fulfilled. The effect of AFM parameters such as applied force, scanning speed and number of pixels of image on nanomanipulation efficiency is investigated. Moreover, the tip is moved along a special path which can be set by software to study manipulation of nanoparticles aggregates. Finally, possible applications of nanomanipulation in nanomechanics, nanoelectronics, nanomaterials and bio-technology are reported and further experimental research works on nanomanipulation are proposed.
Comparison of Cyanide and Chloride-Hypochlorite Leaching of a Ball Milled Refractory Gold Concentrate with Ultra-Fine Particles
Authors: Ghobeiti Hasab Mehdi , Rashchi Fereshteh , Raygan Shahram
Published: November 2013

In this research, cyanide and chloride–hypochlorite leaching of gold from a pyritic concentrate (particle size: −75+53 µm, gold content: 27.15 g/t) were compared. It was shown that only 13.6 % of gold was extracted after 24 h leaching by cyanide, as compared to 37.2 % after 8 h by chloride–hypochlorite. Effect of ultra–fine milling of the concentrate on the leaching was investigated using a high–energy planetary ball mill at different milling times. It was found that the leaching rate of gold by both leachants could be substantially enhanced after the milling of the particles to sub–micron dimensions. This was attributed to the increase of specific surface area and the accumulation of energy in the pyrite particles. After 480 min milling (air atmosphere, 300 rpm, sample/ball:1/20), 96.1 % of gold was extracted by 24 h cyanide leaching, while 100 % extraction could be achieved after only 45 min milling and 30 min chloride–hypochlorite leaching. This was attributed to the oxidation of pyrite by the hypochlorite oxidant and the complete liberation of gold encapsulated in the pyrite particles.
Solvothermal Synthesis of CuInSe2 Nanostructured Powders: Comparing Open-Air with Applying Internal Imposed Pressure
Authors: Khanaki Alireza , Abdizadeh Hossein , Golobostanfard Mohammad Reza
Published: November 2013

Nanocrystalline CuInSe2 (CIS) powders were synthesized with a simple open-air solvothermal method as well as under conditions of applying internal imposed pressure. No post-treating processes such as annealing or selenization were used in both methods. The synthesis processes involved the reaction of precursors in an autoclave for different process times. Structural, morphological, and opto-electronic properties of CIS powders were compared. X-ray diffraction patterns (XRD) confirmed the formation of chalcopyrite structure of CIS powders in both approaches at reaction temperature of 220 °C and for short process time. Field emission scanning electron microscopy (FESEM) results show that while CIS powders synthesized under the atmospheric condition are mostly agglomerated, particles have more specific shapes in samples synthesized under internal imposed pressure. Furthermore, the band gap energies of synthesized CIS powders were obtained using diffuse reflectance UV-vis spectroscopy (DRS) measurements.
Synthesis and Characterizations of Highly Efficient Copper Nanoparticles and their Use in Ultra Fast Catalytic Degradation of Organic Dyes
Authors: Sherazi Syed Tufail Hussain , Soomro Razium Ali , Uddin Siraj , Memon Najma
Published: November 2013

The present study describes synthesis of highly active copper nanoparticles by a green and economically viable approach. The highly stable colloidal dispersions of copper nanoparticles ( Cu NPs) were prepared via modified sodium borohydride reduction route with controlled morphology in a aqueous phase using anionic surfactant, Sodium dodecyl sulfate (SDS), as directing agent and vitamin-C as a Quenching agent. The characterization studies like optimization of various parameters for preparation of nanoscale copper NPs, surface binding interactions, size and morphology of the fabricated Cu NPs were carried out using UV-Visible Spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy, X-Ray Diffraction (XRD) Analysis and Tunneling Electron Microscopy (TEM). The results of study revealed that CuNPs has ultra fast catalytic activity for the degradation of some frequently used organic dyes such as methylene blue (MB) and rose bengal (RB).
Preparation and Mechanical Properties of Short Antheraea pernyi Silk Fiber Reinforced Onion Composite
Authors: Song Ruo Yuan , Zheng Lai Jiu , Zhao Yu Ping , Qian Yong Fang
Published: November 2013

To protect resource and environment, recently, the effective recycling of waste natural resources has been paid increased attention by many countries. In this study, the waste onion was used as the matrix material, and the Antheraea pernyi (A. pernyi) silk was used as the reinforcement fiber. The silk/onion composite paper with different fiber content was developed by papermaking technology. The morphological observation and tensile property tests were done. The consequence indicated that the onion had definite matrix property. Onion cell is also looked as a natural nanocomposite reinforced with cellulose microfibrils. The produced onion paper had a tensile strenght of 29.31 MPa and elongation of 1.14%. The A. pernyi silk fiber originated from waste silk quilt had the good reinforcing property for onion matrix, and the tensile property of onion-based composite with different silk fiber content was investigated. The tensile strength of this green-composite were improved remarkably to 46.2 MPa with increasing 31.75 wt% fiber content. The tensile property of this composite can be futher improved by changing the length of silk fiber and coating additives on the composite surface.
Synthesis and Characterization of Cellulose/Quaternary Phosphonium Salt
Authors: Kong Fan Long , Song Jun , Cheng Bo Wen , Zheng Yun Bo
Published: November 2013

This paper investigates imparting antibacterial properties to wood pulp cellulose via introducing quaternary phosphonium salt groups in/onto the cellulose structure to get biocidal material. The 4-carboxybutyltriphenylphosphonium bromide was grafted to cellulose in an esterification at 70°C with mechanical stirring 5h.The grafted cellulose were evaluated with FTIR and 1H NMR. The product shows good antibacterial property against E. coli.
Preparation, Characterization of Supported Phosphotungstic Acid HPW-MCM-48 and Photocatalytic Degradation of Aqueous Methyl Orange
Authors: Liu Zhe Lin , Guan Li Guo , Liu Zong Rui , Bao Mei Chun , Xu Ling
Published: November 2013

In this paper, heteropoly acids were supported onto mesopore materials MCM-48 with lager surface area and high thermal stability. The supported heteropoly acids catalysts were characterized by FT-IR, XRD, TEM and N2 adsorption-desorption thechniques. In addition, the effects of supported contents of heteropoly acids on degradation rate also had been researched.
Adsorption of Cr (VI) by Cross-Linked Magnetic Hydroxamated Chitosan
Authors: Jia Liang , Wang Jing Song , Guo Qing Wei , Zou Xiao Liang , Xie Lei
Published: November 2013

This paper aims to investigate the adsorption of Cr (VI) by cross-linked magnetic hydroxamated chitosan (MHCTS). The adsorption experiments were carried out in batch systems. To determine the optimum condition of the adsorption, factors such as pH, reaction time, initial Cr (VI) concentration and adsorbent dosage were considered. The experimental results showed that MHCTS can adsorb Cr (VI) with high efficiency. Optimum adsorption was observed at pH 4.0, and the highest adsorption removal reached 99.2%. The equilibrium was established within 90 min. The process could be described by pseudo-first-order and pseudo-second-order kinetic model.
Electro-Thermal Effect Analysis on GaAs PHEMT Based on Physical Model
Authors: Wu Zhao Xi , Fu Gui Cui , Gu Han Tian
Published: November 2013

Considering physical mechanisms, an electro-thermal effect model of GaAs pseudomorphic high electron mobility transistor (PHEMT) was proposed. The model included PAD capacitances, intrinsic elements and extrinsic elements, which represented the relationship of performance parameters to physical structure and temperature. By using this model, the effects of temperature to devices performance parameters could be analyzed, and the device's structure and materials' parameters could be optimized. A typical GaAs PHEMT was simulated in the EDA software. Thus, DC I-V characteristics and small-signal S parameters of PHEMT under varied temperatures could be given.
Creep Properties and Life Estimation of P91 Steel with Low Hardness
Authors: Niu Yu Jing , Cai Hong Sheng , Geng Jin Feng , Ma Dong Fang , Ma Guo Dong , Zhao Yong Feng , Yang Xu
Published: November 2013

The creep properties and creep life estimation experiment was carried out on the P91 steel with low hardness (About 135HBHLD),and the creep life of P91 pipe was estimated.The result was that the ability for anti-plastic fracture, cracking and crack propagation of resistance to damage of high pressure steam conduit pipe with low hardness (About 135HBHLD) is very poor at 566°C and that the working life of low hardness zones (About 135HBHLD) from the creep crack propagation tests is about 5914 hours at 540°C.
Determination of Fluoride in Antarctic Krill Euphausia superba Using Ion Chromatography
Authors: Shen Xiao Sheng , Zhang Hai Yan , Li Yan Lin , Cai You Qiong
Published: November 2013

A simple, rapid and accurate method for the determination of fluoride in Antarctic krill has been developed. The fluoride content in Antarctic krill was determined by ion chromatography. The method requires a simple sample clean-up procedure to remove the interfering Cl- from the hydrochloric acid extraction solution. The optimum extraction conditions of fluoride from Antarctic krill samples were obtained by adding 8mL of 1:11(v/v) hydrochloric acid solution and extracting for 60 min. Under these conditions, recoveries of fluoride from Euphausia superba and Penaeus vannamei were 97.9-105.6% and 95.1-101.9%, respectively. The limit of detection was 0.01mg/kg. The method was applied to the determination of fluoride in Antarctic krill. Key words: Fluoride, Antarctic krill, Ion chromatography
Impact Properties of Particulate Reinforced Aluminum Matrix Composites
Authors: Chen Dong , Li Xian Feng , Zhang Yi Jie , Ma Nai Heng , Wang Hao Wei
Published: November 2013

TiB2 particulate reinforcing 7449 aluminum matrix composites were fabricated by in situ method. Their microstructure and impact properties were investigated. The impact toughness decreases with the increase of the weight fraction of the particulate whereas the hardness of the composites increases. The decrease of impact toughness could be accounted for the particulate cluster and brittle clusions. The increase of the hardness is due to fine grain size and high dislocation density.
Charaterization and Catalytic Activity of CuO and NiO Supported on ZrO2 for CO Low Temperature Oxidation
Authors: Chen Zhi , Xie Yi Long , Qiu Jin Xing , Chen Zhong He
Published: November 2013

ZrO2 support has been prepared by sol-gel and coprecipitation method. CuO and NiO were supported on the supports and they were the activity metals for the catalysts. The CO conversion was tested. The light-off temperature of CO oxidation was 22°C and CO conversion efficiency was up to 50% at 169°C. The prepared catalysts of Cu, Ni supported on ZrO2-A had a high activity for CO oxidation at low temperature.
Characterization and Microwave Absorption Performance of CNTs/Fe3O4/PANI Nanocomposites
Authors: Yang Xiu Ying , Cheng Jun Ye , Zhang De Qing , Gao Mao Sheng
Published: November 2013

Three-phase light-weight CNTs/Fe3O4/PANI nanocomposites were prepared by the co-precipitation of Fe2+ and Fe3+,and a quick process of in situ polymerization of aniline monomer. The structure and morphology of CNTs /Fe3O4/ PANI were characterized by transmission electron-microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and fourier transform infrared (FTIR) spectroscopy. The CNTs/Fe3O4/PANI nanocomposites exhibit less intertwined structure and that many more Fe3O4 particles are attached homogeneously on the surface of CNTs, indicating that PANI can indeed help CNTs to disperse in isolated form. The wave absorbing properties were investigated in a frequency of 218 GHz. The results show that the CNTs/Fe3O4/PANI nanocomposites exhibit a super absorbing behavior and possess a maximum reflection loss of 48 dB at 12.9 GHz, and the bandwidth below 20 dB is more than 5 GHz.
Effect of Artificial Aging on Intergranular Corrosion of 6063 Al Alloy
Authors: Wang Jian Ming , Meng Xiao Dan , Bai Ying Ying , Ma Guo Feng , Liu Yan , He Chun Lin
Published: November 2013

The effect of artificial aging on the corrosion properties of 6063 Al alloy was investigated by optical microscope, field emission scanning electron microscope and accelerated corrosion test. Accelerated corrosion test revealed that the alloy was susceptible to intergranular corrosion (IGC) in the artificial aged conditions according to the surface corrosion morphology, and the IGC resistance was reduced as the aging time was prolonged, resulting from more Mg2Si grain boundary precipitates formed. However, the corroded cross-sections showed that the IGC was very local. Additionally, the surface corrosion morphology also showed that pitting corrosion took place, resulting from galvanic corrosion between (FeMn)3Si12Al15 particles and matrix Al.
Grain Refinement of Mg97Y2Cu1 Alloy Solidified with Pulsed Direct Current Magnetic Field
Authors: Tan Shui Lin , Zhou Quan , Fu Jia Bin , Fu Hao
Published: November 2013

The influences of different pulse voltage, discharging frequency, pouring temperature and mold temperature on marostructure of Mg97Y2Cu1alloy under pulsed direct current magnetic field (PDCMF) were studied and the related mechanism was also discussed. The results show that grains of Mg97Y2Cu1alloy can be refined greatly by PDCMF treatment. Macrostructure of the alloy is changed from coarsened grains to complete fine equiaxed grains. When the pulse voltage is at 0-250V, grain size of the alloy decreases dramatically as pulse voltage increases. When the discharging frequency is at 1-10Hz, grain size of the alloy increases firstly, then decreases, and the turning point is 5 Hz. The change of grain size is not obvious, when the discharging frequency increases from 1 Hz to 5 Hz. When the discharging frequency reaches 10 Hz, the effect of grain refinement is the best. When the mold temperature is at 20-600°C or the pouring temperature is at 660-750°C, grain size of the alloy with PDCMF treatment decreases grossly with the increase of the mold temperature or the pouring temperature. The higher the pouring temperature or the mold temperature, the better the effect of grain refinement with PDCMF treatment.
An Investigation of Carburized Layers on Austenitic Stainless Steels
Authors: Zhang Ting , Tong Xing Sheng
Published: November 2013

In this study, low temperature plasma carburizing of austenitic stainless steels has been studied, with the aim to improve the hardness and wear resistance of austenite layers. Austenitic stainless steels were plasma carburized at 450°C, using C3H8 as carbon carrier gas. Depth profiles of hardness, hardness distribution and the friction coefficient of carburized layer were measured. The results show that carburized layers range from 10 to 20μm, causing the improvement of the hardness and wear resistance of the surface of austenitic stainless steels.
An Experimental Study on Synthesizing TiC-10Ni Composite Coating Using Electro-Thermal Explosion Ultra-High Speed Spraying
Authors: Liu Jing Jing , Liu Zong De
Published: November 2013

In this work, TiC-10Ni coating was synthesized on copper substrate by electro-thermal explosion directional spraying (EEUSS) method at the discharge voltage of 26kV. Electrical characteristics of the explosion were obtained. The foil was overheated in less 26 microseconds. The total electric energy supplied to the foil was 12.7 times the theoretical amount needed to melt the foil. Phase structure and microstructure of the coating were studied by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD from the coating surface consists of TiC and the solid solution of Ni, as well as the residual C. The TiC-10Ni coating, which exhibits no pores or cracks, consists of an irregular spheroidal TiC phase embedded in a nearly continuous binder. TiC particles are uniformly distributed and the size of the TiC particle of the coating is less than 1.0 μm because of the solute trapping effect.
GPU Accelerated Finite Element Simulation for Ultra-High Strength Steel Quenching
Authors: Wang Chao , Zhu Bin , Wang Liang , Wang Yi Lin , Zhang Yi Sheng
Published: November 2013

During the hot stamping of ultra-high strength steel (UHSS), the quenching effect of the mold on the sheet plays an important role to achieve the transition from austenite to martensite. Thus a finite element model for the quenching process of UHSS is established in this paper. The key points of the model include contact thermal conduction and the latent heat processing of phase transforming. Finite element program has been developed to calculate the temperature field of the UHSS quenching process, and temperature measurement device was used to get the temperature-time curve of the mold and the sheet to validate the calculation results. It can be concluded that the latent heat and thermal contact resistance have a critical influence on the temperature filed of the sheet during the hot stamping process. Finally, the parallel computation technology based on GPU(Graphics processing unit) was adopted to accelerate the calculation.
Preparation, Characterization and Magnetic Property of MFe2O4 (m=Mn, Zn, Ni, Co) Nanoparticles
Authors: Yang Li Xia , Li Sha , Zhang Jing , Chen Zhou , Xu Shi Cheng
Published: November 2013

MFe2O4 (M=Mn, Co, Ni, Zn) Nanoparticles with diameters from 5nm to 30nm have been prepared through a hydrothermal method. In this system, ethanolamine was used as a basic source instead of NaOH. The as-prepared ferrites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In addition, the magnetic properties of the obtained ferrites have been studied at room temperature, showing that the magentic properties of ferrites closely depended on the chemical composition of M2+.
The Particle Motion and Power Theory Analysis of Centrifugal Field
Authors: Guo Wei
Published: November 2013

This paper discusses accelerated stress conditions of ore particles in the vertical impact test machine rotor passage through numerical analysis method, and to determine the relationship between the movement of particles and the power and the machine parameters.The results show that:In the test machine rotor, motion law of ore particles is determined, and by expression for the particle displacement, speed and power of the numerical analysis method.If the test machine, gravity effects are negligible;Speed is the main factor affecting the characteristics of particle movement, but should not exclude the influence of particle volume and surface quality;Chasing is never occur in the process of particles;With calculated by the theoretical formula of reasonable size of rotor.
An Approach for Continuous Small Line Blocks High Speed Machining of Embedded Systems
Authors: Wang Yao Ting , Zhang Qiu Ju , Cheng Jin Sai
Published: November 2013

A key issue of the machining for the small line block is to improve the machining feedrate while keeping the machining precision and satisfying the acceleration constraints. In this paper, a new approach for continuous small line blocks high speed machining is proposed to avoid the impact of Computer Numerical Control (CNC) equipments caused by acceleration gust. This approach uses the small line flag to distinguish whether the path is small line block. While the paths are continuous small line blocks, this approach can automatically adjust the number of look-ahead segments, and predigest the velocity calculation method of the connection point. We first define what a path is small line block. Then we analyze the restrictions for velocity linking of adjacent processing paths, and propose the approach for continuous small line blocks machining. Finally we design a simulation experiment on 30 points processing of the spline track. The result of the simulation shows that this algorithm can obviously shorten the processing time and make control system more harmonious in high speed machining.
Finite Element Analysis on the Directly Buried Heating Bent Pipeline with Many Break Angles
Authors: Qian Bao Xian , Wang Fei , Wang Guo Wei
Published: November 2013

In order to get the optimal design scheme of a directly buried heating bent pipeline with many fold angles in a certain practical engineering, this paper simulated the pipeline by the ANSYS finite element analysis software.Through applying different boundary conditions to the model, the stress was analyzed, the destroy forms of the pipeline and the positions of stress danger points were determined,and the fatigue life was checked according to BS EN. Compared with the current design method,adopting numerical simulation analysis method has greatly reduced the number of the usage of compensators and fixed piers, broke through the restrictions for larger fold angle in the standard,and at the same time, it has reduced the construction difficulties and the engineering investment,improved the reliability of the network,this paper has guiding significance to the engineering practice.
Research on a Variable Degree of Freedom Luffing Mechanism, Part II
Authors: Feng Yong Bao , Yao Xiao Guang , Guo Xiao Song , Ma Chang Lin
Published: November 2013

This part mainly focuses on the calculation, analysis and verification of the analytic model of the novel mechanism obtained in Part I. An indirect solution method is presented to simplify the calculation of the motional quantities. Then the kinematic and dynamic equations are solved and some interested results representing the kinematic and dynamic features of mechanism are figured out. A virtual prototype model of mechanism is established in ADAMS to verify the validity of the analytic model and the calculation process. Good agreements between the two models are found from the comparing of trajectory curves, which implies that the modeling, calculation and analysis in this study are accurate.
Crack Propagation in Concrete with Silica Particles
Authors: Sprince Andina , Fischer Gregor , Pakrastinsh Leonids , Korjakins Aleksandr
Published: November 2013

The propagation of cracking in concrete is a mechanism governing many physical and mechanical properties of the material. The aim of this study was to experimentally investigate the crack propagation of new concrete compositions using image analysis. Several concrete mixes containing microsilica and nanosilica were made. For each composition, Compact Tension (CT) specimens were prepared with dimensions 150x150x12mm. Specimens were subjected to a tensile load. The formation and propagation of the tensile cracks was traced on the surface of the specimens using a high resolution digital camera with 60 mm focal length. Images were captured during testing with a time interval of one second. The compression strength and modulus of elasticity were also determined for reference. The results obtained with this method have shown that it is possible to monitor relatively small displacements on the specimen surface regardless of the scale of the representative area of interest and to evaluate the influence of filler on the cracking properties of concrete.
Structural Behaviour of Single Layer Space Frame with Member Arrangement Following Spiral Phyllotaxis
Authors: Choong Kok Keong , Kim Jae Yeol
Published: November 2013

The regular arrangement of the plant organs is botanically known as phyllotaxis. Among the types of phyllotaxis found in nature, spiral phyllotaxis is the most frequently found pattern. The unique arrangement of this pattern in plants has benefited most of the plant structure as it enables them to grow more efficiently and compatible for physical constraints such as moisture and amount of light falls. In this research, the unique spiral phyllotaxis pattern has been adopted as idea for member arrangement pattern for structural space frame system. Two type of spiral phyllotaxis pattern and one regular model are generated. Analysis using finite element software LUSAS has been carried out in order to determine the effect of member arrangement following spiral phyllotaxis on stresses and displacement in the space frames.