bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Soft Clay on Slope Stability
Authors: Md Ghazaly Zuhayr , Abdul Rahim Mustaqqim , Isa Nur Fitriah , Sofri Liyana Ahmad , Azizi Azizan Muhammad , Ibrahim Fazdliel Aswad
Published: April 2015

Slope stability is very important on designing a safe slope. If this were to be taken lightly by the engineer, major disaster will occur that results in lost of lives. Each engineer is responsible to evaluate all aspects of design, especially when designing a slope gradient on the surface of soft clay. Soft clay containing high water content and if not planned properly, water from the soft clay will seep into the slope and causes reduction in soil strength. The purpose of this research was to investigate the effect of water absorption of soft clay on the stability of the slope. The objectives of this study were to analyze the soil strength when the soil were soaked in water to a set of different time range and to analyze slope stability on soft clay based on the infiltration of water from underground using PLAXIS software. In this study, soil samples were taken and laboratory experiments were carried out to obtain the unit weight, cohesion, and friction angle of the soil samples. The experiments involved were grain size analysis test and unconfined compression test. Data from the experiments will be used in PLAXIS software to obtain the factor of safety.
Synthesis of Epoxidised Silsesquioxane Polymer as Negative Photoresist in Photolithography Application
Authors: Ramli Mohamad Riduwan , Ahmad Zulkifli , Mohamed Khairudin
Published: April 2015

Epoxidised silsesquioxane (EPSQ) polymer was prepared by hydrosilylation process involving epoxy-disiloxane (EDS) and vinyl silsesquioxane (VSQ). They were characterised and analysed using Fourier Transformed Infrared (FTIR) and H-and Si-Nuclear Magnetic Resonance (NMR) spectroscopy. Pattern development was successfully performed affording well defined features of micron scale using suitable solvent developer. It was demonstrated that the feature definition was highly dependent on time of solvent dissolution and stirring rate. Optimization of several parameters such as resist thickness, pre-bake and post-bake time, ultra-violet (UV) intensity and exposure time are still required for the improved performance photo-resist material. However the results proved that the EPS can be potentially used as photoresist in photolithography application.
Influence of Micron-Size Activated Carbon Additions on the Microstructure, Microhardness and Thermal Properties of Sn-Cu-Ni (SN100C) Solder Fabricated via Powder Metallurgy Method
Authors: Izwan Ramli Mohd Izrul , Saud Norainiza , Mohd Salleh Mohd Arif Anuar , Derman Mohd Nazree , Said Rita Mohd , Nasir Norhayanti
Published: April 2015

Composite solder has drawn attention improvement in microstructural modification and mechanical properties. This research was done to investigate the influence of activated carbon (AC) particulate on the commercial Sn-Cu-Ni solder system (SN100C) solder alloy. The SN100C+AC composite solder was fabricated via powder metallurgy (PM) technique. In this study, five different AC compositions were chosen; (0, 0.25, 0.5, 0.75 and 1.0 wt. %. This study has shown that composite solder has better properties compared to the monolithic solder alloy. A small amount of AC particulate had improved the physical properties of the composite solder. Microstructural analysis showed that the reinforcement was well distributed along the grain boundaries and no significant influence on the melting point of SN100C. Apart from that, 1.0 wt. % of AC additions results with the highest hardness value compared to the other composition.
Mechanical Properties and Solderability of Robust Sn-0.7Cu Lead-Free Composite Solder
Authors: Musa Sayyidah Amnah , Saud Norainiza , Razak Nurul Razliana Abdul , Hussin Kamarudin
Published: April 2015

A composite solder with Sn-0.7Cu based solder was successfully fabricated via powder metallurgy routes which consist of mixing, compacting and sintering. Varying amount of activated carbon (AC) was used as reinforcement to obtain a novel lead-free composite solder. Following fabrication, the sintered composite solder was analyzed in terms of their microstructure, microhardness and solderability properties. The distribution of the various percentages of AC particles along the grain boundaries was observed. The addition of AC particles into the Sn-0.7Cu solder matrix has increased the hardness values up to 22.9%, while reducing the contact angle of composite solder up to 12.9% for a good wettability performance. As overall, addition of AC into Sn-0.7Cu based solder has indicated an enhancement of reliability performance of Sn-0.7Cu/AC composite solder for electronic application.
The Study of Al-N Codoped ZnO Thin Films Prepared by DC Magnetron Sputtering
Authors: Hamid Haslinda Abdul , Abdul Hadi M.N.
Published: April 2015

The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 200 °C and 600 °C for 1 hour in nitrogen and oxygen gas mixture. Structural investigation was carried out by scanning electron microscopy (SEM), atomic force microscopy and x-ray diffraction (XRD). Film roughness and grain shape were found to be correlated with the annealing temperatures.
Potential of Corn Starch as Fluid Loss Control Agent in Drilling Mud
Authors: Ghazali Nurul Aimi , Alias Nur Hashimah , Mohd T.A.T. , Adeib S.I. , Noorsuhana M.Y.
Published: April 2015

Fluid loss can be defined as the lost of mud filtrate into a porous permeable formation due to high hydrostatic pressure compared to the formation pressure. This phenomenon may cause some major problems to the workover operation such as formation damage, stuck pipe, and poor cementing job. Thus, in order to prevent fluid loss into formation, an environmentally safe, non-toxic, high biodegradability and low cost of polymer additive in drilling mud was prepared from corn starch as the fluid loss control agent. The purpose of this study is to investigate the potential of utilizing natural polymer-corn starch acting as fluid loss control agents in water-based drilling mud. The filtration and rheological properties of the water-based mud were analyzed at 170 to 200 °F temperature range with 0 to 10 g of corn starch concentration. Experimental results showed that the higher concentration of corn starch gave better fluid loss control behavior. Therefore, there is high potential of corn starch to be used as fluid loss control agent in drilling mud.
Cure Characteristics, Tensile and Physical Properties of Recycled Natural Rubber Latex Glove (NRL-G) Filled Acrylonitrile Butadiene Rubber
Authors: Dahham Omar Sabbar , Noriman N.Z. , Ting Sam Sung , OMAR MOHD FIRDAUS , Alakrach Abdulkader M.
Published: April 2015

The use of recycled natural latex rubber glove (NRL-G) as a reinforced material filled acrylonitrile butadiene rubber (NBR) was studied. The compounds of different NRL-G loading (0, 10, 20 and 30 phr) were prepared by using two roll mills at room temperature. Two different size ranges of NRL-G such as 300μm-700μm (fine) and 2cm-4cm (coarser) were used. The properties such as cure characteristics, tensile and physical properties were determined. The NBR/NRL-G compound with the fine size of NRL-G exhibits overall good cure characteristics and physical properties compared with coarser size. The addition of the of 20 phr content NRL-G (fine) contributed to the optimum tensile properties than coarser size.
Green Functionalization of Activated Carbon for Dye Removal Application
Authors: Mohamad Hashim Ahmad Zulfadli , Sufian Suriati , Shima Shaharun Maizatul
Published: April 2015

A study of water as the agent of functionalization is still new since most of researchers used acid as the agent of functionalization. The objective of this study is to investigate the used of water as a medium of functionalization of commercialized activated carbon in order to be used in removal of methylene blue dyes from synthetic wastewater via adsorption. The parameters for functionalization of the commercialized activated carbon included temperature at 35°C, contact time of 5 hours and various frequency at 100, 150 and 200 rpm. The experiment was conducted in a batch process where the commercialized activated carbon were functionalized under the mentioned parameters. The functionalized activated carbon were characterized using Fourier Transform Infra-Red (FTIR) Spectroscopy. The FTIR analysis indicated the increase of the amount of functional group attached to the activated carbon. The dye adsorption study was conducted by using methylene blue solution with initial concentration of 500 ppm as adsorbate and the functionalized activated carbon as adsorbent. A standard calibration curve for methylene blue solution was generated using of Ultraviolet-Visible (Uv-Vis) Spectrophotometer. The result from the adsorption study was the parameter of temperature at 35°C, contact time of 5 hours and varying water bath shaker frequency at 100 rpm yield the best adsorption rate.
Dimensional Characterization of Surface Contours of Cut Surfaces with Plasma Straight Metallic Materials
Authors: Machedon-Pisu Teodor , Kamarudin Hussin , Machedon Pisu Elena
Published: April 2015

The purpose of this paper is to analyze the dimensional accuracy of the surfaces straight edges from cutting plasma free atmosphere or water bed. The aim was to identify any defects and if bed piss water cut in some way influence the surface quality and dimensional contours right. Mechanical thermal plasma cutting bed prevents overheating of the water has the advantage that the base material and thus the parameters related to compliance with the slag assures cut pieces at the bottom, this saves the cost of production. Mechanized plasma cutting bed heat the water does not affect the value of angle tolerance compared to cutting outdoor (angular deviation determined either for parts or cut outdoor water bed ranged between 7-9 degrees / side). The causes of and ways to reduce the deviation angle cut edge is determined by other factors such as cutting speed, distance torch-material, cutting nozzle erosion.
Chitosan and Bentonite as Coagulant in Dissolved Air Flotation Tank
Authors: Mohd Arif Zainol Mohd Remy Rozainy , Mokhtar Hasif , Sutan Syafalni , Abdul Wahab Khairy , Al Bakri Abdullah Mohd Mustafa
Published: April 2015

The use of monocoagulants, such as Chitosan, may not be a good solution for highly turbid water purification because of its high cost. The possibility to reduce the amount of the primary coagulant at the same time keeping the removal to be in optimum may be a good strategy to reduce the operation cost. There might be another coagulant aid for example the natural clay of Bentonite to reduce the cost. The initial stage is to determine the Bentonite dosage and mixture ratio to be used with Chitosan. Coagulation of Chitosan-Bentonite had successfully removed the turbidity with the efficiency of 97%. The coagulants performed well when Chitosan-Bentonite ratio is 30:70 at concentration of 1000mg/l
Ab Initio Calculations of Electronic Properties of Al Doped LaMnO3 Perovskite Manganites
Authors: Chik Abdullah , Saad S. , Zaki R.M. , Pa Faizul Che , Yeoh C.K.
Published: April 2015

The electronic structure of the perovskite manganites LaMnO3 and La2/3 Al1/3 MnO3 was presented. The calculations were made within density functional theory (DFT) and PBE exchange correlations energy approximation. It was found that inclusion of Al dopants add additional states near the Fermi level and decreasing the resistivity values for all temperature range.
The Structural Properties Evaluation on Ultra-Thin Surfacing Hot Mixture Asphalt Concrete
Authors: Budiarto Arif , Purnomo Hafid Riyan , Setyawan Ary
Published: April 2015

Overlay as the conventional method to maintain the surface quality of pavement need a large number of fresh natural aggregate and bitumen due to the relatively thick layer and consequently the road geometric must be corrected, so that regarded as not environmentally friendly. The alternative solution is Ultra-Thin Surfacing Hot Mix Asphalt (UTSHMA) which has a thickness of 12-15mm. UTSHMA gradation is designed based on the highest Marshall Quotient value tested by performing Marshall Test of five variations gradation from Standard Specification Construction of Transport Systems. The Optimum Bitumen Content (OBC) obtained by Marshall Test. The bitumen used for this is 60/70 penetration. The several structural tests were performed on the best gradation at OBC consist of Marshall tests, Indirect Tensile Strength (ITS), Unconfined compressive strength (UCS) tests and water permeability test. The UTSHMA mixture with coarse gradation has the greatest Marshall Quotient at 6.35% OBC accompanied by the higher ITS and UCS properties compare to conventional asphalt concrete. The coefficient permeability of UTSHMA is lower than conventional AC, indicated that UTSHMA is more resistant to water penetration. The research concluded that UTSHMA has compromised the standard specification and has sufficient structural properties compare to conventional AC and can be regarded as structural layer of pavement for overlay and road preservation design.
Mechanical Properties of High Density Polyethylene (HDPE)/Sawdust Composites under Wide Range of Strain Rate
Authors: OMAR MOHD FIRDAUS , Jaya Haliza , Akil Hazizan Md. , Ahmad Zainal Arifin , Noriman N.Z.
Published: April 2015

An experimental approach based on the conventional universal testing machine (UTM) was employed to perform low strain rate loading (0.001/s, 0.01/s and 0.1/s) in this research, to examine the reliance of natural filler contents towards HDPE/sawdust composites. By following to the low strain rate loading, static compression properties of HDPE/sawdust composites with varies filler contents of 5 wt% SD, 10 wt% SD, 15 wt% SD, 20 wt% SD and 30 wt: % SD were successfully studied. The results show that the yields stress, ultimate compression strength and the rigidity properties of HDPE/sawdust composites were sturdily affected by both filler contents and strain rate loadings. Moreover, for the post damage analysis, the results clearly show that different static loading employed to the specimens gives significant effects towards deformation behavior of HDPE/sawdust composites. The increasing of static loading employed caused the specimens to experience severe deformation.
Studying Effect Dimensions of Design and Simulation Silicon Nanowire Filed Effect Biosensor
Authors: Wesam Al-Mufti M. , Hashim U. , Rahman Md. Mijanur , Adam Tijjani , Md Arshad Mohd Khairuddin , Rahim Ruslinda A. , Ramzan Mat Ayub
Published: April 2015

We investigated into report a study biosensor based on silicon into an effect on the dimensions of conductance design and simulation nanowire surface with molecular DNA for sensitivity. In the design nanowire of A biosensor with 3 layers starting with polyisilicon nanowire of radius 8 NM surrounded by a 50-nm electrode layer, and the substrate by a 300nm. COMSOL Multiphysics software used to provide interaction with molecules such as DNA and the distribution of the electrostatic potential in the narrower due to the dimensions, surface nanowire charge was computed using Poisson equation with Boltzmann statistics. In the result of the effect geometry was also studied and the different dimension yield different space charge and the surface charge at interactive site were also investigated and the study demonstrate steps wise identification of all critical parameters for (DNA) attachment with surface nanowires.
The Study of Damage Area and Non-Destructive Testing on Glass Fibre Reinforce Polymer after Low Velocity Impact Event
Authors: Razali N. , Sultan M.T.H.
Published: April 2015

This paper discussed on damage area and non-destructive testing on Glass Fibre Reinforced Polymer (GFRP) after low velocity impact event using drop weight impact tester. Specimens from C-type and E-type fibreglass fabricated in 10 layers with size 150 mm x 100 mm, were subjected to low-velocity impact with circular steel impactor at various energy levels from 10 J to 40 J. Visual observation techniques using a lab microscope were used to determine the damage visual by looking at the crack. Dye penetrants were used to inspect the area of damage and to evaluate the internal and external damage on the specimens after impact. The results from the experiment were discussed and presented.
Spinach Ferredoxin (Fdx) as an Organic Material to Improve Optical Band Gap of Chitosan (Cs) Biofilm
Authors: Chandrasakaran Devi Shantini , Nainggolan Irwana , Derman Mohd Nazree B. , Nasution Tulus Ikhsan
Published: April 2015

In this study, the effect of spinach-ferredoxin addition in chitosan matrix towards optical band gap was investigated. 5 distinct solutions were prepared by blending chitosan and spinach-ferredoxin (Cs-Fdx) with the volume to volume ratios of 100:0, 95:5, 90:10, 85:15 and 80:20 respectively. The solutions were cast into film via spin coating technique. The optical properties in terms of absorbance for these films were investigated using UV-Vis Spectrometer. UV-Vis result showed that the absorbance increased as the spinach-ferredoxin content increases. Finally, the optical band gaps of the films were determined by extrapolating a straight line of (αhν) 2 vs. hν curves. Band gap value of 3.48 eV, 3.25 eV, 3.2 eV, 3.0 eV, and 2.8 eV were observed for (Cs-Fdx) films with 100:0, 95:5, 90:10, 85:15 and 80:20 respectively.
Grafting of Itaconic Anhydride onto Natural Rubber as Compatibilizer for Rubber Blend, Experimental Optimization of Grafting Extent
Authors: Puteh Muryanee , Klinpituksa Pairote , Kaesaman Azizan
Published: April 2015

Graft copolymers of natural rubber with itaconic anhydride (IA) were prepared in toluene using benzoyl peroxide (BPO) as an initiator. The effects of reaction temperature, reaction time, monomer concentration and initiator concentration on natural rubber grafting were investigated. Graft copolymers (NR-g-IA) were characterized by Fourier transform infrared spectroscopy (FTIR). The grafting content of IA onto NR was estimated by means of FTIR using the absorbance peak ratio for 1783 cm-1 and 835 cm-1, corresponding to the symmetric C=O stretching and the =C-H out of plane bending in natural rubber, respectively. Titration was also used to determine the amount of IA grafted onto natural rubber. The optimal grafting conditions for preparation of NR-g-IA were found at 10 phr IA, 2.5 phr BPO, 85°C temperature, and 2.5 hr reaction time.
Adsorptive Removal of Ni2+ from Aqueous Solution Using Rice Husk-Based Activated Carbon
Authors: Taha Mohd Faisal , Shuib Anis Suhaila , Shaharun Maizatul Shima , Borhan Azry
Published: April 2015

An attempt was made to study the potential of rice husk as an alternative cheap precursor for activated carbon to remove Ni2+ from aqueous solution. Rice husk was treated chemically (with NaOH) and physically (carbonization) to prepare rice husk based activated carbon (RHAC). The textural properties of RHAC, i.e. surface area (255 m2/g) and pore volume (0.17 cm2/g), were determined by N2 adsorption using Brunauer-Emmett-Teller (BET) surface analyzer. RHAC was also characterized for its morphology and its elemental compositions. The adsorption studies for the removal of Ni2+ from aqueous solution were carried out using different dosage of RHAC as adsorbent as a function of varied contact time. The concentration of Ni2+ was determined by atomic absorption spectrometer (AAS). The results obtained from adsorption studies indicate good potential of rice husk as a cheap precursor to produce activated carbon for the removal of Ni2+ from aqueous solution. The equilibrium data from adsorption studies fitted well the of Langmuir and Freundlich isotherm models.
Processing of Apatite-Wollastonite (AW) Glass-Ceramic for Three Dimensional Printing (3DP)
Authors: Alharbi N. , Khan Shah Fenner , Bretcanu O. , Dalgarno K.W.
Published: April 2015

Apatite-wollastonite glass ceramics (AW) in bone regeneration and replacement applications have been seen as a favourable alternative to allografts and autografts. A-W has good biocompatibility, bioactivity, chemical stability and mechanical properties. In this study AW was used to fabricate 3D parts for bone applications by an indirect three dimensional printing (3DP) technique. Various powder blends of AW and maltodextrine (MD) were processed using the Z Corp 3D printing process, with two different liquid binder systems. The green parts were post-processed through using a heat treatment to burn off the binder and sinter the powder particles. Consistent results were obtained for all tested specimens in terms of density, porosity and shrinkage. The highest strength after sintering was 35.6 MPa.
In Vitro Cytotoxicity and Mutagenicity Evaluation of Dental Leucite Glass-Ceramics from Local High Grade Silica Sand
Authors: Bt Saiyed Mohd Nurddin Siti Mazatul Azwa , Selamat Malek
Published: April 2015

The objective of the study was to determine the degree of biocompatibility of leucite glass-ceramics that have been produced from local high grade silica sand in terms of cytotoxicity and mutagenicity assays. In the present study, the cyctotoxicity and mutagenicity were studied using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay (MTT) and Ames Reverse Mutation. In the MTT assay, a dose response cytotoxicity of leucite sample was evaluated in L929 cells. The cells were treated with the concentrations of 6.25, 12.5, 25.0, 50.00, 100.00 and 200.00 mg/ml of the leucite sample for 24 hours. The cytotoxicity was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The mutagenenicity of leucite sample was evaluated in S. typhirium TA98. TA100, TA1535, TA1537 and E. coli WP2 in the Ames Reverse Mutation assay. Mutagenic effects were evaluated by comparing the mean number of revertant colonies of each extract concentraction with mean number of revertant colonies of the negative control. In results of MTT assay evaluated that the leucite did not show a cytotoxic effect at all concentrations under the condition of the study. Ames Reverse Mutation assay result proven that the leucite sample did not demonstrate a mutagenic effect under the condition of this study with Salmonella typhimurium and Escherichia coli.
Application of Sulfated Magnetic Nanoparticles in the Synthesis of Biologically Active Ureas
Authors: Kuksenok Vera U. , Shtrykova Victoria V. , Filimonov Victor D. , Galanov Andrey I.
Published: April 2015

It has been shown that nanoparticles Fe2O3@SO3H easily form salts with pharmacophoric benzhydrylamines. The obtained nanocomposites were successfully used in the “green” synthesis of valuable benzhydrylureas with the anticonvulsant activity.
Heat and Mass Transfer in Wet Fibroporous Material Considering Moisture Evaporation
Authors: Polovnikov V.Yu. , Gubina E.V.
Published: April 2015

Results of numerical simulation of heat and mass transfer in a wet fibroporous material in conditions of evaporation and steam diffusion were completed. Values of heat and mass fluxes were established. The contribution of evaporation effect to total heat flux and need to consider volume fractions of water and steam into the structure of fibroporous material in calculation of effective thermal conductivity were shown. Nonstationarity of heat and mass transfer in conditions of considered problem can be ignored.
Studying Phenazine Derivatives from Pseudomonas aeruginosa
Authors: Palchevskaya Yekaterina S.
Published: April 2015

Phenazines represent a group of heterocyclic nitrogen-containing compounds showing a broad spectrum of antibiotic properties. Phenazines are studied extensively for their further application in plant disease management. Pseudomonas aeruginosa produce three phenazine compounds as the secondary metabolites. These metabolites are known as phenazine-1-carboxylic acid (PCA), 2-hydroxyphenazine-1-carboxylic acid and 2-hydroxyphenazine (2-OH P). In this study separation and characterization of phenazines were done by using thin layer chromatography (TLC), column chromatography and ultraviolet (UV) spectrum. Two compounds were isolated and their concentration was identified.
Heart Condition Imaging with the Help of the Cardiographic Equipment on Nanosensors
Authors: Grigoriev Michael , Turushev Nikita V.
Published: April 2015

Precision methods and devices for diagnostics of cardiovascular diseases are one of the main directions for development of modern technology in the field of medical instrument engineering. However, there are no small devices that allow for the diagnostics of cardiac muscle with precision accuracy and without operative intervention at this stage. This study presents the problems associated with cardiovascular diseases (CVD) and the analysis of various organizations engaged in development of efficient means for CVD diagnostics. Two-component FitzHugh - Nagumo model and heart condition imaging algorithm are considered. Aspects of work aimed at designing and developing of the hardware and software complex based on the information obtained with the help of an electrocardiograph on nanosensors. The obtained results are presented.
Rapid and Clean Biomimetic Synthesis of Bimetallic Au-Ag Nanoparticles Using an otherwise Worthless and Noxious Weed Ipomoea (Ipomoea carnea)
Authors: Ganaie Sami Ullah , Ravindran Sruthi , Abbasi Tasneem , Abbasi Shahid Abbas
Published: April 2015

In a first report of its type, gainful utilization of the obnoxious weed ipomoea (Ipomoeacarnea;also known as:I.fistulosa) has been achieved by developing a procedure on its basis for clean-green one pot synthesis of bimetallic Au-Ag nanoparticles. In it the leaf and the stem extracts of the weed serve as reducing as well as stabilizing agents. With the support of Scanning Electron Microscopy, Confocal Raman Spectroscopy, and X-ray based techniques, the effect of varying metal: extract stoichiometry, temperature, and stirring on controlling the shape and size of the nanoparticles has been studied. Increase in reaction temperature is seen to favour speedier formation of nanoparticles, and of smaller average size, than occurs at ambient temperatures (27±2°C). Higher extract: metal ratios also lead to nanoparticles of larger average size. When Ag (I) and Au (III) salts are used in equal molar ratios, it generates sphere-shaped nanoparticles. All-in-all, the present work offers a non-polluting, energy saving, and cost effective route for the fabrication of bimetallic Au-Ag nanoparticles. The study indirectly provides a means of controlling ipomoea, thereby offering a means to reduce the ecological degradation that is caused by the weed.
Production of Ibuprofen-Loaded Solid Lipid Nanoparticles Using Rapid Expansion of Supercritical Solution
Authors: Akbari Zahra , Amanlou Massoud , Karimi-Sabet Javad , Golestani Abolfazl , Shariaty Niassar Mojtaba
Published: April 2015

The purpose of this study was to prepare ibuprofen loaded solid lipid nanoparticles (IBU-SLNs) that is, effective in oral drug delivery. IBU-SLNs were synthesized by co-precipitation of rapid expansion of supercritical solution (CO-RESS). The produced SLNs consisted of stearic acid as lipid matrix. The unprocessed stearic acid, ibuprofen and IBU-SLNs were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), fourier transform infrared spectrophotometry (FTIR) and high performance liquid chromatography (HPLC). XRD patterns along with DSC showed that ibuprofen was present in both amorphous and crystalline form within lipid matrix. FTIR showed that molecular interactions that could alter the chemical structure of the IBU did not occur. The RESS process could produce ultrafine spherical particles of SLNs with high drug loading capacity. The IBU dissolution profile showed that the formulated SLNs have effectively increased the IBU solubility
Synthesis and Characterization of Copper Nanoparticles by Electrochemical Method: Effect of pH
Authors: Anand Vikky , Harshavardhan  , Srivastava Vimal Chandra
Published: April 2015

Herein, copper nanoparticles were synthesized using electrochemical method at pH 5, 6.5, 9.5 and 12.5 (coded as Cu5, Cu6.5, Cu9.5 and Cu12.5, respectively). Copper was used as electrode whereas 0.15 M oxalic acid in aqueous solution was used as an electrolyte. Effect of pH of the electrolyte solution on the morphological, structural and textural properties of prepared copper nonoparticles was studied. Prepared nanoparticles were characterized by X-ray crystallography, Field emission scanning electron microscope, transmission electron microscopy, thermogravimetric analysis, differential thermal analysis and textural analysis. The morphology and sizes of the nanoparticles prepared varied with the initial pH of the solution. Sizes of synthesized Cu particles were found to be in the range of 20 nm to 7 μm. All the particles were mesoporous in nature. Cu5 was found to contain 67% copper hydroxide and 33% copper oxalate whereas Cu6.5, Cu9.5 and Cu12.5 essentially consisted of copper hydroxide.
Light Metals Chips Recycling by Plastic Consolidation
Authors: Tokarski Tomasz , Wędrychowicz Mateusz , Wiewióra Marcel
Published: April 2015

In this work, hot extrusion of light metal scraps as a new way of plastic consolidation will be presented. This kind of material recovering is a promising alternative for conventional recycling processes. Nowadays discards from machining of semi-finished products are being recycled throughout re-melting processes. However, due to its significant susceptibility to oxidation most of the chips and scraps are burnt during the melting process. It has been already recognized that aluminum losses connected with this operation can reach from 40% to 50%. A technology that has been presented in this work combines cold compaction and hot extrusion of 413.0 aluminum alloy scraps. It was found that quality of as-extruded rods depends strongly on extrusion conditions. Higher extrusion speed leads to higher quality of rods surface. Additionally brittle Si and Al-Fe-Si particles increases overall mechanical properties in comparison to its industrial counterpart.
Production and Properties of AgW50 Composites Designated for Electric Contacts
Authors: Osadnik Małgorzata , Czepelak Marian , Kamińska Małgorzata
Published: April 2015

The purpose of the studies was to determine production parameters of AgW50 composite contact material. Fabrication of contact tips from this material was carried out by powder metallurgy method including preparation of the powder mixture, pressing, sintering and optional repressing under pressure of not less than 600 MPa. This technology enables production of contact tips with different shape and size without application of machining. The required material structure, i.e. uniform distribution of tungsten particles in the silver matrix, was achieved by milling conducted in the planetary ball mill. The further operations of this technological process, i.e. optimization of consolidation parameters, enabled fabrication of material characterized by high density and functional (electrical) properties.
Effects of Surface Forces on Pure Squeeze Elastohydrodynamic Lubrication Motion of Circular Contacts with Coated Layer
Authors: Chu Li Ming , Li Wang Long , Chen Qie Da , Yu Chi Chen , Yeh Chi Yang
Published: April 2015

The effects of surface forces (SF) on pure squeeze elastohydrodynamic lubrication (EHL) motion of circular contacts with coated layer are explored under constant load condition by using the finite element method (FEM) and the Gauss-Seidel iteration method. The difference between SFEHL model and EHL model is apparent as the film thickness is thinner than 5 nm. The oscillation phenomena in pressure and film thickness come mainly from the action of solvation forces. The effects of surface forces become significant as the film thickness becomes thinner.
Combined Diamond Disks in Chemical Mechanical Polishing
Authors: Tsai Ming Yi , Ho J.K. , Zeng Jyu Lin
Published: April 2015

This paper presents a combined diamond disk that is designed and manufactured to markedly improve the leveling of diamond tips, thereby reducing the amount of diamond grit. First, a small brazed diamond disk was manufactured. Second, 12-or 24-disk brazed diamond disks were mounted onto a substrate with a diameter of 108 mm for completing the combined diamond disk. Four types of disks were fabricated, and their performances were compared with that of a conventional diamond disk. The experimental results showed that the combined diamond disk has more complete diamond crystal shapes and distribution with better leveling, which increases the effectiveness of the working diamond grits. Compared to a conventional diamond disk, the combined diamond disk achieved a higher wafer removal rate and better uniformity while consuming less pad material. The number of diamond grits required was significantly lower. Roughly, 7,600 and 12,000 diamond grits were used for the 24-and 12-disk brazed diamond disks, respectively, in the new disk, whereas 20,000 diamond grits were used in a conventional diamond disk. In the case of the conventional diamond disk, the diamond tips are leveled to more than 50 μm. However, in the case of the combined diamond disk, the diamond tips can be leveled to less than 30 μm because the diamond tips are already leveled. These results contribute to the understanding of conditioning techniques and further improvement of the chemical mechanical polishing process.
The Influence of Velocity Variation on the Adhesive Contact Behavior and the Deformation of Substrate Based on Molecular Dynamics Method
Authors: Chen Jing Jing , Huang Jian Meng , Liu Yang , Gao Sheng Fu , Li Ning
Published: April 2015

The contact behavior between indenter and single crystal copper substrate is performed to investigate based on EAM and Morse potentials and Verlet algorithm. Effects of different velocities on the contact behavior and substrate deformation are compared and analyzed. The results show that the single crystal copper material’s resist deformation level is limited by low velocity, and more dislocated atoms were accumulated under the direction of indenter moving in higher indenting velocity. During sliding process, lager chip volume is produced in front of the indenter as the sliding speed or sliding distance increases. The dislocated band in basis lies at the angle of 45 degrees with the direction of indenter moving in indenting and sliding process. Furthermore, the contact force, friction force and normal force increase with the rising of speed. On the contrary, the friction coefficient decrease gradually with higher sliding speed.
The Effect of CNT Content on the Tribological Properties of CNTs Doped Diamond-Like Carbon Films
Authors: Wei Che Hung , Yang Jui Feng , Wang Chao I
Published: April 2015

Diamond-like carbon (DLC) films is useful in many applications. To improve the tribological properties in DLC, we spin coat the multi-walled carbon nanotubes (CNTs) with different solution on (100) silicon. DLC was deposited by plasma enhanced chemical vapor deposition (PECVD) with C2H2 and H2. The results show that the ID/IG ratio is increasing with higher CNTs content while the friction coefficient and critical load are decreasing with larger CNTs contents. The decreasing friction coefficient results from graphitation on the surface due to higher sp2 content. The decreasing critical load is attributed to higher internal stress. The effect of friction coefficient and CNT concentration on stress distribution is studied by a nanoscratch finite element analysis. The results indicate that low friction coefficient and high CNT concentration will reduce the stress magnitude in the film. Therefore, the decreasing friction coefficient in CNT doped DLC film with increasing CNT concentration should reduce stress in the film and is good for adhesion. The discrepancy between friction coefficient and critical load is explained in terms of high internal stress during deposition. A surface treatment on CNT before deposition to reduce internal stress is currently under investigation.
The Effect of Surface Modification of Polytetrafluoroethylene (PTFE) on the Properties of POM/PTFE Fiber Composites
Authors: Huang Chi Yuan , Kuo Mei Chuan , Roan Min Lih
Published: April 2015

Surface modification of polytetrafluoroethylene (PTFE) fiber by plasma grafting polymerization with acrylamide (AAm) was studied to improve the compatibility between polyacetal (POM) and PTFE. The best modified PTFE manufactured by self-designed plasma polymerization was investigated and denoted as AAm (20wt%)-g (plasma 30min)-PTFE. The grafting polymerization is successful and shown by ESCA spectra of modified PTFE fibers. It is also proved by SEM photographs and the improvement of properties of the POM/PTFE composites. As a result, the friction coefficients, Taber wear factors, and impact strengths of composites with 85wt% of POM and 15wt% of a variety of PTFEs were investigated. The frictional coefficient of POM/ AAm (20wt%)-g (plasma 30min)-PTFE deceased to 0.162; while that of POM/PTFE was 0.174. Taber wear factor of the composite significantly decreased from 5.2 to 1.5 when the PTFE was replaced by AAm-g (plasma)-PTFE. Meanwhile, the impact strength increased from 6.1 kg-cm/cm (POM/PTFE) to 9.3kg-cm/cm (POM/ AAm-g (plasma)-PTFE). Besides, the multi-yield behaviors were found in the Stress-Strain curves of composites with modified PTFE fibers.
Fabrications of Electroless Ni-P Composite Coatings before and after Annealing and Tribological Analyses
Authors: Chang Chang Shuo , Hou Kung Hsu , Ger Ming Der , Chung Chen Kuei , Lin Jen Fin
Published: April 2015

In the present study, SiC reinforced particles were introduced to the Ni-P plating bath, and developed high SiC content composite coatings. Thin films nature properties and mechanical performances were evaluated well. The results showed that the Ni-P alloy embedded SiC particles formed a few cavities, and reduced coatings hardness and wear resistance in as-plated condition. After 400°C heat-treatment, Ni3P crystalline phase formed and reached the max hardness, and conducted excellent trybological performances. SiC particles were decoposited in 600°C and reacted with Ni to form Ni3Si and Ni5Si2, caused the decreasing in hardness.
The Effect of Rotational Speed on Fluid Compressibility and Gap Pressure of a Partially Porous Aerostatic Thrust Bearing
Authors: Huang Te Yen , Lin Sheam Chyun , Shen Song Chiang , Hsu Shao Yu
Published: April 2015

This study investigated the effect of the spindle speed on pressure distribution in the air gap and the load carrying capacity of a porous aerostatic annular thrust bearing. Based on the finite volume method and the pressure-velocity coupling scheme of the SIMPLE algorithm with the standard k-ε turbulent model, a CFD software was used to solve the Navier-Stokes equations to calculate pressure and velocity of the air flow. The results revealed there were positive pressure zones and vacuum pressure zones in the air gap between the thrust disk and the bearing. Under the same spindle speed, the pressure difference between the positive peak and the negative peak in the case of incompressible air was greater than that in the case of compressible air. The averaged pressure on the surface of the thrust disk with compressible air flow was higher than that with incompressible air flow. So was the load carrying capacity of the bearing, which increased when the spindle rotated faster.
Vibration Suppression Evaluation of Smart Journal Bearing Using Giant Magnetostrictive Actuators
Authors: Wang Wen , Cai Sheng Zong , Wu Chao , Wong P.L.
Published: April 2015

A new kind of smart hydrodynamic journal bearings with giant magnetostrictive actuators (GMA) is introduced. The static and dynamic displacement outputs of the designed GMA are up to tens of microns, about the same order of magnitude as the conventional journal bearing clearance. Vibration suppression of the new smart journal bearing is theoretically evaluated using a simple Jeffcott rotor-bearing system. Kinematic equations are set up including the magneto-mechanical coupling model for GMA. The bearing oil film force under large vibration is calculated using a fast and efficient non-stationary oil film database technique. The unbalance vibration orbit of the rotor center is simulated. A simple synchronous proportional control method for GMA with different control phases and gains is investigated. The suppress effect of unbalance vibration and improvement of oil whip unstable speed is evaluated. The simulation proves that the new journal bearing has better stability, and that rotor vibration can be actively suppressed.
The Effects of Environmental Temperature and Humidity on the Friction and Wear Performance of PTFE Braided Composites
Authors: Chen Yue , Zhu Chang Ling , Liu Jian
Published: April 2015

With the rapid development of advanced science and technology, the performance requirements of the PTFE fabric composite is rapidly increase. In this work, the dry friction tests of PTFE braided composites were carried out on high-speed Tribo-tester analysing the influence of different working conditions to the friction temperature and humidity in the measurement of friction characteristics experiments. Scanning electron microscopy (SEM) was utilized to examine composite microstructures and study modes of failure. Energy spectrometer analysis was also performed to study the wear surface and the ingredient of the debris in an effort to get the mechanism of the composites damage.
Numerical Simulation on Variable Load EHL Problems with Single Asperities
Authors: Zhang Jian Jun , Liu Cheng Long , Guo Feng
Published: April 2015

A model of the problem of variable load line contact EHL with single asperities is established. The influences of the single asperities and variable load on the pressure and film thickness are investigated. Numerical results reveal that the existence of single asperities can lead to pressure change drastically and film thickness become thin in the vicinity of asperities. The effects of the variable load on the pressure and film thickness are discussed. The comparison of the variable load and steady load is given.
Network Carbide Inheritance during Heat Treatment Process of Large Shield Machine Bearing Steel GCr15SiMn
Authors: Zhang Dan , Zhou Le Yu , Zhang Chao Lei , Huang Chao , Zhao Min , Liu Ya Zheng
Published: April 2015

Network carbide inheritance during heat treatment process of large shield machine bearing steel GCr15SiMn was investigated by heat treatment experiments and quantitative metallographic. Samples with the proeutectoid cementite network thickness in the range of 0.19~0.54 μm were obtained by changing austenitizing temperature and soaking time of pearlite transformation. The results show that the network in hot rolled bar can be improved when the pre-heat treatment temperature is 950 °C. When the network thickness is above 0.40 μm, the undissolved cementite networks present in microstructures after quenching and tempering. In a Chinese standard, the network grades are 1.5 and 3.0 degree when the networks thickness are 0.40 μm and 0.54 μm, respectively. The critical network thickness that can be eliminated by heat treatment is 0.29 μm.
Effect of Niobium Additions on Austenite Grain Coarsening Behavior of GCr15 Bearing Steel
Authors: Liu Xiang , Zhao Fan , Dong Zheng Qiang , Zhang Chao Lei , Kou Yu Shan , Liu Ya Zheng
Published: April 2015

The effect of 0.018% niobium additions on austenite grain coarsening behavior of GCr15 bearing steel was studied. Results indicate that the coarsening temperatures of No.1 and the No.2 experimental steel were 950°C and 1100°C. The austenite grain coarsening temperature was increased by 150°C by the addition of 0.018% Nb in bearing steel. The grain growth equations of two experimental steels at different soaking temperatures from 850°C to 1250°C with the soaking time of 30 min are as follows: the equation of No.1 steel is D1=1.85×105·exp (-6.57×104/RT); the equations of No.2 steel below and above 1100°C is D2=5.08×102·exp (-2.49×104/RT) and D2=1.06×108·exp (-1.31×105/RT), respectively. The grain growth equations of two experimental steels at different soaking time from 15 to 120 min with the soaking temperature of 840°C are as follows: the equation of No.1 steel is D1=4.83×10-2·t0.72 while that of No.2 steel is D2=1.25·t0.18.
Research on Microstructure and Properties of Base Metal and Weld of Electron Beam Welding 0.30C-Cr-W Steel
Authors: Li Lin Tao , Yang Mao Sheng , Ren Yun
Published: April 2015

Due to the difficulty of manufacturing complex small pieces ofthe new bearing steel0.30C-Cr-W with high-performance in the aviation industry, the electron beam welding process are usually used for preparing the complex parts.Thewelding performance of 0.30C-Cr-W steelwas calculated by theory and confirmedby actual experiments.The base metal was preheated,then welded and heattreated for weldments.The purpose of this work is to study the properties and the microstructure changes of base metal after heat treatment, weldments before heat treatment and weldments after heat treatment.The results show that the base metalafter heat treatment is sorbitic,weldzone of weldments after heat treatmentismartensite and austenite, theprecipitated M23C6 and M6C in latter (the weld zoneof weldmentsafter heat treatment) were more thanthe former (the base metalafter heat treatment), and the strengthof the latter is 23.4%lower than the former, theroom temperature impact absorbing energy and hardness of the latter increased 13.5% and 6.6%. It may be considered that0.30-C-Cr-W steel is not suitablefor welding by the theoretical calculations, but after reasonable preheat and post-weld heat treatment, the mechanical properties of the weld afterheat treatment can satisfy the requirements.
Research on Fluctuations in Work Hardening Rate of a Fe-Mn-Al-C Steel
Authors: Zhao Chao , Song Ren Bo , Zhang Lei Feng , Yang Fu Qiang , Qin Shuai
Published: April 2015

The fluctuations in the work hardening rate of a Fe-12Mn-10Al-0.7C (wt. %) steel have been investigated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The work hardening rate of the heat treated sample had a tendency of decrease with fluctuations. The first raise in the work hardening rate curve at about 2% true strain is attributed to the shearing of the small ferrite grains by austenite, and the deformation induced twinning can contribute to the raise and drop in the work hardening rate curve. The second fluctuation range at the true strain between 10% and 14% is mainly related to the activation of planar slip on the principle slip plane which is suppressed by twins in austenite.
Study on A-TIG Welding Technology for 12 mm Thick 304 Stainless Steel Plate
Authors: Yi Yao Yong , Liu Guan Hui , Zhang Yu Peng , Luo Zi Yi , Xu Lei
Published: April 2015

A-TIG welding is a new variant of high-efficiency TIG weld technology, the weld penetration can be improved by using surface activating fluxes. In the present work, 12 mm thick stainless steel plates were welded by A-TIG method utilizing self-developed oxide-based composite activating flux. Results showed that for 12 mm thick stainless steel plates, weld joint of full penetration and one-side welding with back formation and good weld appearance could be achieved by A-TIG welding. Furthermore, compared with traditional TIG welding, the microstructure of A-TIG weld was finer, directivity of dendritic crystals near weld bond line was weaker, and mechanical properties of weld joints was also superior.