bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Plate Gap on the Fatigue Properties of Friction Stir Welded AA5182-H111 and a Comparison with MIG Welding
Authors: Hattingh D.G. , Bernard Dreyer , von Wielligh L.G. , James M. Neil
Published: October 2014

In industrial applications tight control during weld set-up equates to increased manufacturing cost. Solid state welding processes, particularly friction sir welding, do not generally make use of filler metals and hence a weld gap will have an influence on joint quality. In the current study the influence of a weld gap of 20% of the plate thickness (i.e. 1mm) in friction stir welded (FSW) joints was compared dynamically to welds made without a gap. These results were benchmarked against samples joined through MIG welding, a widely used method to join aluminium plates in industry. Tests revealed that the introduction of a 1mm gap caused a steeper slope of the stress-life curve of the friction stir welded joints when compared to flaw free welds made without a weld gap. Crack initiation in the 1mm gap FSW samples occurred at the advancing side weld edge where the tool shoulder interacts with the material, while the flaw free ‘zero gap’ welds failed in the parent material from the marks induced during oxide removal. Intermittent root flaws were, however, present in the welds made without a weld gap which decreased the life of the samples as the area of the flaw was increased. MIG welded samples always failed from the weld toe and the fatigue life of these samples were considerably lower than that of the 1mm gap friction stir welded samples. In the friction stir welded samples containing root flaws, a flaw across the entire sample width was required to reduce the life of the friction stir welds to that reached by the MIG welded samples.
Mechanical Properties and Microstructures of Nano SiC Reinforced ZE10 Composites Prepared with Ultrasonic Vibration
Authors: Song Jiang Feng , Dieringa Hajo , Huang Yuan Ding , Gan Wei Min , Kainer Karl Ulrich , Hort Norbert
Published: October 2014

In the present investigation, SiC reinforced ZE10 alloy composites were fabricated by direct chill casting assisted with ultrasonic vibration. Two kinds of SiC with a size of 50 nm and 2 μm were chosen. For comparison, ZE10 alloys with and without ultrasound were also fabricated. The microstructures and the distribution of SiC were examined by optical microscopy and scanning electron microscopy. Neutron diffraction was also used to identify the second phases in the composites. In addition, mechanical properties such as hardness, creep and compression were evaluated. The results show that SiC was successfully introduced into the magnesium matrix. After the addition of SiC, the mechanical properties of the composites exhibit a slight decrease, which might be due to the grain coarsening.
Submicron Grain Size Formation in Thermohydrogenated and Deformed Ti-6Al-4V: The Effect of Processing Route on the Degree of Grain Refinement
Authors: Vilane V.N. , Knutsen R.D. , Westraadt J.E.
Published: October 2014

The aim of this work was to refine the as-cast Ti-6Al-4V grain size and its Widmanstätten morphology to optimise the mechanical performance of Ti-6Al-4V castings. Hydrogenation and deformation were used as variables in processing routes aimed at assessing the degree of refinement in the as-cast Ti-6Al-4V microstructure. Thermohydrogen processing (THP) refined the Widmanstätten morphology and not the prior beta grain boundary network. Therefore, the degree of refinement in THP processing is limited to morphology refinement within pre-existing prior beta grains. Deformation processing and recrystallisation is necessary to eliminate the indelible influence of the prior beta grain boundary network on the extent of THP refinement. In this context, a substantial degree of refinement is achieved from thermohydrogen and deformation processing (THDP). The as-cast Ti-6Al-4V grain boundary network was refined from an average diameter of 2000μm to 20μm. In addition, the Widmanstätten morphology was refined to submicron equiaxed alpha and beta grains.
Investigating the High Temperature Oxidation Behavior of TiAl-Based Alloys with Nickel and Ruthenium Additions
Authors: Mantyi H.C. , Cornish L.A. , Chown Lesley H. , Mwamba I. Alain
Published: October 2014

Pure powders of titanium, aluminium, nickel and ruthenium were mechanically alloyed and melted in a button arc furnace under an argon atmosphere to produce two alloys of composition Ti-52.5Al-10.0Ni (at.%) and Ti-52.5Al-10.0Ni-0.2Ru (at.%). The alloys were then cut and metallographically prepared. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to characterize the samples. Thermogravimetric analysis (TGA) was used to analyze the oxidation behavior from room temperature up to 1050°C. The alloys were also oxidized in air at 1050°C for 120 hours. The Ti-52.5Al-10.0Ni (at.%) alloy formed dendrites of γ-TiAl (55.6 at.% Al) surrounded by a eutectic of γ-TiAl + Al3NiTi2(τ3) phases. The Ti-52.5Al-10.0Ni-0.2Ru (at.%) alloy formed dendrites of γ-TiAl (53.6 at.% Al) surrounded by a eutectic of γ-TiAl + Al3NiTi2(τ3). The ruthenium was mostly in solid solution (0.3 at.%) in the Al3NiTi2(τ3) phase, although traces of it were present in the dendrites (0.1 at.% Ru). When oxidized in air from room temperature to 1050°C, the as-cast Ti-52.5Al-10.0Ni-0.2Ru (at.%) had a mass gain of 0.60% and the as-cast Ti-52.5Al-10.0Ni (at.%) had a mass gain of 0.97%. Isothermal oxidation of both alloys at 1050°C for 120 hours formed mixed metal oxides of TiO2+Al2O3on the surface.
Chatter Investigation in Titanium Milling
Authors: Fwamba Jean Claude , Tshabalala Lerato Crescelda , Ntuli Cebo Philani , Tlhabadira Isaac
Published: October 2014

Titanium and its alloys have been experiencing extensive development over the past few decades. They have found wide applications in the aerospace, biomedical and automotive industries owing to their good strength-to-weight ratio and high corrosion resistance. Machining performance is often limited by chatter vibrations at the tool-workpiece interface. Chatter is an abnormal tool behaviour which is one of the most critical problems in the machining process and must be avoided to improve the dimensional accuracy and surface quality of the finished product. This research aims at investigating chatter trends in the end milling process and to identify machine parameters that have effects on chatter during machining. The machine parameters investigated include axial feed rate, spindle revolute speed and depth of cut. In this research, experimental data was collected using sensors to analyze the existence of chatter vibrations on each processing condition. This research showed that the combination of the machine parameters, feed rate and spindle speed within certain proportions has an influence on machine vibrations during end milling and if not managed properly, may lead to chatter.
Preparation of Pt-Promoted Co/SiO2 Catalysts for CO Hydrogenation by Strong Electrostatic Adsorption (SEA)
Authors: de Beer Martin , Claeys Michael , van Steen Eric
Published: October 2014

Cobalt-based Fischer-Tropsch catalysts typically contain noble metals as reduction promoters to enhance the amount of the catalytically active metal in these catalysts after activation. The noble metal is typically co-impregnated with cobalt, which does not necessarily ensure the optimum contact between the noble metal and cobalt. The noble metal can be selectively deposited on the precursor of the catalytically active metal for the Fischer-Tropsch synthesis, if strong electrostatic adsorption (SEA) is the dominant mechanism. The point of zero charge of silica (Davisil 646) (PZC = 2-3) and that of Co3O4(PZC = 9-10) differs significantly. This results in a pH region where it is theoretically possible to selectively deposit the noble metal onto Co3O4using anionic exchange (e.g. using PtCl62-). The effect of pH on the uptake of these metal anions was investigated and found that adsorption is favored at low pHs. The reduction characteristics of Co3O4/SiO2,promoted by SEA, were investigated by temperature programmed reduction (TPR) and thermal gravimetric analysis (TGA). The peak maxima for reduction temperature for both steps of the reduction of Co3O4to CoO and of CoO to Co3O4decrease in the promoted catalyst, the activation energy for the first step decreased from 84±11kJ/mol to 50kJ/mol upon promotion. The degree of reduction was also noted to increase from 48% in unpromoted Co/SiO2to 56% and 84% in two different Pt-Co/SiO2systems.
Tantalite Beneficiation through Sequential Separation of Radioactive Elements, Iron and Titanium by Magnetic Separation and Acid Leaching
Authors: Nete Motlalepula , Purcell Walter , Nel Johann T.
Published: October 2014

The Process Beneficiation of Minerals such as the Tantalum and Niobium Ores May Vary Significantly and the Final Sequence of Steps Normally Depends on the Physiochemical Properties. these Properties are Often Utilised in Designing a Processing Route. Removal of Iron and Titanium from the Manganotantalite and Ferrotantalite Samples in this Study was Successfully Accomplished by Magnetic Separation. Acid Leaching Using H2SO4 on the other Hand Removed a Large Portion of Thorium and Uranium in these Samples. Analytical Results Indicated that 66(1) and 54.7(5)% of Total Fe and Ti Respectively, and ~ 2% each of Nb2O5 and Ta2O5 were Removed from Ferrotantalite Using the Magnetic Separation Method, while only 9.0(1) and 8.61(4)% of Total Fe2O3 and TiO2 Respectively, and ~2% each of Nb2O5 and Ta2O5 were Removed from Manganotantalite. Tantalite Ores Leached at 50 °C for 3 Hrs in the Presence of Concentrated H2SO4 was Found to be the most Appropriate Condition to Remove Radioactive Elements. Results Obtained from Sample A under these Conditions Indicated that 62(2)% U3O8 and 60.8(3)% ThO2 were Leached into the Acidic Solution along with 4.45 and 0.99% of Nb2O5 and Ta2O5 Respectively.
Corrosion Behaviour of the Anodised A356 Aluminium Alloy Produced by the Rheo-High Pressure Die Casting Process
Authors: Chauke Levy , Mutombo Kalenda , Govender Gonasagren
Published: October 2014

Semi-solid metal forming of aluminium alloys has demonstrated the capability to produce near net shaped high integrity components. Anodising of these components for aesthetic and/or improved corrosion resistance is specified by some designers or users of this technology. The corrosion behaviour of fully anodised and partially anodised A356 aluminium alloy plates produced using the CSIR Rheo-High Pressure Die Casting (CSIR-RHPDC) process was investigated using immersion testing in a 3.5% NaCl solution with pH = 7. Optical microscope equipped with image analysis software and scanning electron microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate the behaviour of the corroded samples. The fully anodised sample showed that the anodised surface displayed some surface degradation. This degradation was more severe on the anodised surface with surface liquid segregation (SLS), but provided sufficient protection to prevent corrosion of the base metal. The partially anodised sample showed severe corrosion of the based metal with the corrosion concentrated in the silicon rich eutectic and SLS regions.

 
Research on ELID Grinding Efficient Surface Forming Mechanism of SiCp/Al Composites
Authors: Guan Jia Liang , Zhu Lei , Chen Ling , Ma Xin Qiang , Zhang Xiao Hui
Published: October 2014

The electrolytic in-process dressing (ELID) grinding technology was adopted for precision grinding experiments of volume fraction of 40% of SiCp/Al composites, obtaining the machined surface roughness of Ra0.030μm. Studying the forming mechanism of processed surface, analyzing several typical grinding surface defects, summarizing the grinding characteristics and removal mechanism of SiCp/Al composites.
Analysis and Simulation of Air Flow Field Surrounding Grinding Wheel
Authors: Wang Chun Yu , Zhang Lei , Yang Chun Feng
Published: October 2014

In grinding, high specific heat is generated and hence it is very important for the fluid to remove heat from the grinding contact zone to avoid thermal damage to the workpiece surface and/or sub-surface layers. In conventional grinding, a stiff air layer is generated due to the rotation of the porous grinding wheel at high speed. Hence, most of fluid isn’t penetrated into the grinding contact zone because of the stiff air layer around the grinding wheel. To improve grinding fluid cooling effection and avoid thermal damage, it is necessary to analyze the air flow and stiff air layer around the grinding wheel. Based on fluid dynamics and mathematical simulation method, the 3D finite element model of the air flow field around the grinding wheel is developed. The air flow pressure field and flow velocity near the grinding zone are analyzed. In results, the pressure and the velocity of the air flow near the grinding zone increase with the wheel speed increase, and the pressure and the velocity of the air flow near the grinding zone increase with the minimum gap between the grinding wheel and the workpiece reducing. After the air is drived by the grinding wheel into the high pressure area near the grinding zone, the air flows around both sides of the grinding wheel and there are no obvious returning air flow phenomena.
Study on the Dullness of Monolayer Brazed Diamond Grinding Wheel through Plate Wheel Dressing
Authors: Zhang Kun , Su Hong Hua , Dai Feng Ming
Published: October 2014

A monolayer brazed diamond grinding wheel was dressed 23 times with a plate wheel. The grinding forces were measured during the grinding experiments which carried out on SiC ceramics after each dressing interval. The surface roughness of SiC ceramics was also measured. In this study, the dullness of the grinding wheel during the dressing procedure is mainly discussed. The results showed that the surface roughness of SiC ceramics reduced a lot after dressing which means the dressed grinding wheel can meet the requirements of precision machining. On the premise of this, there was no obvious dullness occurred on the grits of the grinding wheel during dressing because new cutting edges had emerged.
Simulation of Temperature Distribution in HFCVD Diamond Films Growth on the End Surfaces of Seals
Authors: Liu Jian Jin , Song Bo , Zhang Tao , Sun Fang Hong
Published: October 2014

The uniform temperature flied of substrates is a key factor to deposit high-quality diamond films on milling tools by the hot filament chemical vapor deposition (HFCVD). In this study, a 3-D computational model is established to simulate the temperature distribution on the substrates. Thereafter, the influence of the rotational speed of worktable n and the water flux of water-cooled worktable Q are investigated. The simulation results show that the increasing of the rotational speed of worktable is suitable to grow homogeneous diamond films and gently decrease the even temperature of seals. What’s more, the deceasing of the water flux will significantly increase the overall temperature of seals.
Analysis of Chemical Action of Oxidants in Chemical Mechanical Polishing of SiC Crystal Substrate
Authors: Fu Su Fang , Yao Jian Guo , Ma Li Jie , Su Jian Xiu
Published: October 2014

Chemical mechanical polishing (CMP) had been considered as the most practical and effective method of achieving an ultra-smooth and non-damage surface in manufacturing SiC crystal substrate. CMP slurry was one of the key factors of CMP technology. In this paper, through investigating the changes of several core factors to evaluate the performance of CMP, such as the material removal rate (MRR), surface roughness Ra, 3D surface profiler, etc., the influence of various slurry and its content on the polishing efficiency and surface finish quality had been studied. The research results showed that different oxidant had different chemical action mechanism, also affecting the stability of CMP slurry and surface quality of specimen; adding suitable an oxidant to slurry could effectively improve the CMP performance.
Analysis of Temperature and Thermal Stress Distribution on KDP Crystal Wire Saw Slicing
Authors: Jiao Yang , Ge Pei Qi , Gao Yu Fei , Bi Wen Bo
Published: October 2014

Temperature variation of KDP crystal is an important reason for its cracking. A finite element model was constructed to analyze temperature and thermal stress distribution of KDP crystal during wire saw slicing. The results showed that the highest temperature of the crystal which was located on the sawing kerf remained stable during slicing. The temperature inside the crystal rose slowly at the start of the slicing, and then tended steady with the continued increase of sawing depth. Because of the good cooling condition during the sawing process, the overall rise in temperature was small, and the maximum thermal stress on the sawing kerf was less than the tensile strength of KDP crystal, so temperature variation during slicing had little effect on crystal cracking.
Effects of Processing Parameters of Oxide Layer in Ultrasonic Vibration and Electrolytic In-Process Dressing Combined Grinding
Authors: Zhao Bo , Jia Xiao Feng
Published: October 2014

In order to study the states of oxide layer under different pre-dressing process conditions in ultrasonic vibration and electrolytic in-process dressing combined grinding. The effects of electrical parameters, wheel speed, ultrasonic vibration on the oxide layer are investigated with indicators of oxide layer surface morphology and thickness characteristics. The results indicate that the oxide layer thickness increases with the decrease of inter-electrode gap and the increase of duty ratio with pre-dressing time. The effect of ultrasonic vibration cause thinning of the oxide layer. Oxide layer surface morphology allowing processing requirements are obtained by duty cycle of 5μs: 5μs, electrode gap of 0.3mm, wheel speed of 3200 r/min.
Diamond Tool Wear Reduction by Combining Ultrasonic Elliptical Vibration with Graphite Particle Atmosphere
Authors: Gao Xing , Li Chao Jiang , Li Yong , Duong Cam Vinh
Published: October 2014

For reducing diamond tool wear in ultra-precision cutting of ferrous metals, a process of combining ultrasonic elliptical vibration with graphite particle atmosphere was put forward. An experimental setup was built integrating an ultrasonic elliptical vibration mechanism with a jet lubrication device on a 4-axis ultra-precision lathe. The frequency of ultrasonic elliptical vibration is 38.36 kHz with a trajectory of 8.5×3.5μm. Graphite particles with sizes of 1.3~2μm were selected. Conventional cutting and the combined method were conducted on die steel. Compared with conventional cutting with a wear land width of about 300μm, diamond tool wear in the combined method was decreased to about 20 to 30μm. The combined method is feasible to further reduce the diamond tool wear when cutting die steel.
Design of Special Ultrasonic Device in Composite Materials Processing
Authors: Wang Xiao Bo , Zhao Chong Yang
Published: October 2014

According to the unique advantage of the ultrasonic vibration processing in brittle materials, a new processing method, combining ultrasonic vibration and high-speed milling, was presented in this paper, to investigate an adaptation of high-quality and efficient processing in carbon fiber composites. Based on vibration theory, the special ultrasonic vibration milling device suitable for high speed machining centers was designed. Taking into account of a range of issues existing in contact electrical transport under high-speed processing, the contactless induction power transmission system was developed, and the impacts of load, frequency, air gap size as well as the existence of compensation on the transmission performance was discussed. The study shows that carbon fiber composites processed under ultrasonic vibration with high speed, high quality and high efficiency are adapted. Keywords: ultrasonic vibration milling; carbon fiber composites; contactless induction; tool wear
Machining Mechanism of Fresnel Lens Mold
Authors: Guan Jia Liang , Ma Xin Qiang , Cao Cheng Guo , Zhang Xiao Hui , Zhu Lei
Published: October 2014

This paper analyzed the large diameter Fresnel lens mold machining mechanism based on modal test methods .The design and mold machining principle of Fresnel lens were introduced . Explored the cutting speed and feed on chip formation process. The results show that: the material strength and plastic brittle have significant impact on chip morphology in the H62 brass mold processing, an improvement of material strength with the increase of strain rate and the evolution process of the chip can be divided into: ribbon cuttings, serrated chips, cell chips.
Process Experiment Research and Equipment Development of ELID Lapping
Authors: Guan Jia Liang , Chen Ling , Zhu Lei , Zhang Xiao Hui , Ma Xin Qiang
Published: October 2014

In this paper, according to the principle and the existing technology of ELID grinding, we use the existing lapping machine of Wenzhou Runsheng ceramic water valves factory as the experiment platform to develop an ELID lapping process system. Then utilizing ELID ultra-precision lapping technology to process alumina ceramic seals obtained a good effect. The roughness of processing samples reached about 15nm which was demanded by the enterprise, the efficiency increased 60% and the cost reduced 50%. On this basis, we designed an ELID lapping prototype. It laid a solid theoretical and practical basis for the production of ELID lapping machine in the future.
Research on Cylindrical Precision Machining Adopting ELID Grinding Technology
Authors: Guan Jia Liang , Zhang Xiao Hui , Chen Ling , Ma Xin Qiang
Published: October 2014

In order to explore the new way to precision machining of the cylindrical, ELID precision mirror grinding technology are employed to precision ultra-precision grinding experiments. Given ELID precision mirror grinding technology has effectively solved the basis of many of the typical flat-precision machining difficult materials and efficient processing, through the conversion process equipment tools, and optimization of process parameters, obtained when the wheel speed in 16 ~ 20 m / s, when the grinding depth 10μm, cylindrical grinding state is best, which could obtain Ra0.025μm surface roughness of the machined surface.
Synthesis of Co/CNTs via Strong Electrostatic Adsorption: Effect of Metal Loading
Authors: Akbarzadeh Omid , Mohd Zabidi Noor Asmawati , Abdullah Bawadi , Subbarao Duvvuri
Published: October 2014

Cobalt particles were deposited on treated CNTs via the Strong Electrostatic Adsorption (SEA) method. Cobalt loading on CNTs support was varied from 5 to 20 wt%. Samples were characterized by N2 adsorption and HRTEM. The results of TEM indicated that increasing the metal loading from 5% to 20% resulted in larger nanoparticles and also led to agglomeration.
Effect of Cell Material on the Performance of PV System
Authors: Nahar Afroza , Hasanuzzaman M. , Rahim N.A. , Hosenuzzaman Md.
Published: October 2014

Interest of renewable energies is increasing due to the revising the energy policies for fighting against the emission of Carbon-dioxide. To make the development of the civilization sustainable and cause less harm to the environment, clean energy resources are very important. Many alternative renewable energy resources are available that can be used instead of fossil fuels. Solar energy is one of the potential alternative renewable energies. This paper presents differents types of Photovoltaic cell materials which is one of the most effective parameter for improvement of photovoltaic cell as well as Photovoltaic system performance.
Synthesis of C-2-Ethoxycarbonylmethoxyphenyl Calix[4]Resorcinarene Using Salicylaldehyde as Basic Material and its Application as Adsorbent of Pb(II) Metal Cation
Authors: Mulya Putri Widya , Jumina  , Siswanta Dwi , Gusti Ngurah Budiana I M.
Published: October 2014

Synthesis of C-2-ethoxycarbonylmethoxyphenyl calix [4] resorcinarene and its application for adsorption of Pb (II) metal cation have been carried out. C-2-ethoxycarbonylmethoxyphenyl calix [4] resorsinarene was produced in three steps i.e (1) esterification of 2-chloro acetic acid, (2) reaction ethyl 2-chloro acetate with salicylaldehide in to yield 2-ethoxycarbonylmethoxy benzaldehyde, and (3) reaction 2-ethoxycarbonylmethoxy benzaldehyde with resorcinol in acidic condition to yield C-2-ethoxycarbonylmethoxyphenyl calix [4] resorcinarene. The prepared compounds were characterized by FTIR, 1H-NMR dan 13C-NMR spectrophotometers. The adsorption kinetic of Pb (II) adsorption in batch followed pseudo 2nd order kinetic model. The isotherm study showed that the adsorption followed Langmuir model.
Solidification Behaviour of a H21 Tool Steel
Authors: Nurbanasari Meilinda , Tsakiropoulos Panos , Palmiere Eric J.
Published: October 2014

Solidification behaviour of a H21 tool steel has been studied. The aim of this work is to give better understanding of the as cast microstructure of the steel. The investigated H21 tool steel was made using induction vacuum furnace with air cooling. The microstructure observation was carried out using optical and electron microscopy. X ray diffraction and nanohardness were also used for phase and carbide identification. The results show that the as cast microstructure consisted of ferrite and coarse primary M6C carbide that is rich in tungsten. The nanohardness of ferrite was 5.1 ± 0.3 GPa and there was inhomogeneity in as cast microstructure, which is indicated by the nanohardness values from bulk grain to grain boundary precipitates varied between 4.8 to 8.9 GPa. Comparison between prediction and experimental results shows that the calculated phase diagram was not in agreement with the solidification microstructure of the H21 tool steel.
The Influence of Carbon Addition on Microstructure and Mechanical Properties of Fe-22.0Al-5.0Ti Alloy
Authors: Kant Ravi , Selokar Ashish , Agarwala Vijaya , Prakash U.
Published: October 2014

The effect of carbon addition on Fe-22.0Al-5.0Ti alloy on structure and properties has been investigated. Microstructural and phase analysis have been investigated by using optical microscopy, scanning electron microscope (SEM) equipped with EDAX. For low carbon addition (0.1 wt.%), two-phase microstructure consisting of precipitates of TiC in B2 matrix. The presence of large amount of carbon (1.0 or 1.5 wt.%) resulted formation of Fe3AlC0.5 and TiC precipitates in B2 matrix. The results show that the mechanical properties of Fe-22.0Al-5.0Ti increased with increase in the carbon content and strongly depend upon nature and volume fraction of different precipitates. The volume fraction of precipitates increased with increase in the content of carbon. The behavior of Fe-22.0Al-5.0Ti alloy was explained by the combined effect of precipitation hardening and solid solution strengthening. The main effect of addition of carbon related to improvement in the compressive strength without loss in the ductility. The decrease in the wear rate is mainly attributed to the high hardness of the composites and as well hard TiC play a role of load carrying.
Hydrophobicity Characterization of Bio-Wax Derived from Taro Leaf for Surface Coating Applications
Authors: Nasri Noor Shawal , Ahmed Murtala Musa , Mohd Noor Naemah , Mohammed Jibril , Hamza Usman Dadum , Mohd Zain Husna
Published: October 2014

The hydrophobic properties as well as the presence of 1-octacosanol of taro wax extracted from taro leaf were investigated using various analytical techniques. The bio-wax extraction was achieved by immersing taro leaves samples in 500 mL chloroform at 50°C for 30 seconds and the step was repeated for the same sample using fresh chloroform. The solvent was evaporated using rotary evaporator and the raw bio-wax solution was obtained. Hydrophobicity test showed the average time for the test was 981s which exceeded the 300 s limited for hydrophilicity. TGA results indicate the existence of multi-components in taro wax with the decomposition occurring at three stages. The DSC result showed that the taro wax is composed of at least two contents, ie lower content with smaller melting point range of 50 to 60°C as well as upper content with higher melting point range of 65 to 75°C. Contact angle of droplets of distilled water on the taro wax surfaces were found to be greater than 900 and this confirmed its hydrophobic property. The n-octacosanol presented was identified through FTIR and GC-FID analyses. The functional compounds OH, CH3, CH2, and C=O were detected. From the GC-FID, the n-octacosanol was presented at 34.5 min compared to the standard solution. Plant base taro wax can be a source of sustainable and renewable hydrophobic material for use in HVAC application system.
Characteristics of Potassium Acetate - Activated Coconut Shell Carbon
Authors: Nasri Noor Shawal , Mohammed Jibril , Ahmad Zaini Muhammad Abbas , Hamza Usman Dadum , Mohd. Zain Husna , Ani Farid Nasir
Published: October 2014

There is significant portion of agricultural wastes in the world posing environmental challenge; however, they could be converted into useful products like activated carbon. In this study, coconut shell based carbons were synthesized using chemical activation with potassium acetate (PAAC), potassium hydroxide (PHAC) and physical activation by CO2 (CSAC). The properties of potassium acetate-activated carbon were characterized and the results were compared with the other activation methods. The pyrolysis temperature of 700°C for 2h yielded 32% of char. The BET surface area and pore volume of PAAC are 622m2/g and 0.31cm3/g; while 369m2/g and 0.19cm3/g, and 1354m2/g and 0.61cm3/g were recorded for CSAC and PHAC, respectively. CSAC yielded lower surface area with approximately 88% micropores. On the other hand, PAAC yielded higher surface area with approximately 50% of both micropores and mesopores, whereby this heteroporous property would suffice for a wider range of application. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes, carbonyls and aromatics functional groups were identified with more prominent peaks on the chemically activated porous carbons. From thermogravimetric analysis (TGA), lignin decomposition occurred in a wider temperature range (390-650°C). The properties of PAAC could offer a sustainable means for treatment of toxic waste streams.
Development of Natural Bio-Plantation Waste as Pulp for Paper Making
Authors: Ng Guo Tong , Ng Chui Kim
Published: October 2014

This project investigated the use of facile pulping methods to produce pulp from mixed bio-plantation waste fibres using sodium hydroxide, ethanol and garbage enzyme. Papers were successfully made from mixture of corn husk fibres with other bio-based green fibres such as banana stems and pineapple leaves. Soda pulping was found to be efficient in converting the cellulosic bio-fibres to the pulps used for paper making. The papers produced have low tensile strength, high water absorption, high bio-decomposition and degradation rate, as compared to commercial papers. SEM observation revealed that paper made from mixed bio-fibres have lightly cross-linked structures compared to heavily cross-linked or compact network structures found in commercial papers. The paper can be used in applications that require high water absorbency. The paper making process is more environmental friendly as it reduces the usage of wood fibres and hence reduces the environmental problem caused by deforestation.
Structural Response of Offshore Blast Walls under Accidental Explosion
Authors: Rahman Shaikh Atikur , Syed Zubair Imam , Kurian John V. , Liew M.S.
Published: October 2014

Adequate blast resistant barriers are requisite to protect personnel and critical systems from the consequences of an accidental explosion and subsequent fire. Many of the blast walls currently installed in offshore structures were designed using simplified calculation approaches like Single Degree of Freedom models (SDOF) as recommended in many design guidelines. Over simplified and idealised explosion load used for response calculation and design of blast wall can lead to inadequate or overdesign of offshore blast walls. Due to lack of presence of a well-accepted design guidelines supported by extensive study, the protection provided by the conventional blast walls for offshore structures can be inadequate. In-depth understanding of structural response of blast walls under different blast loading can provide better design practice of blast walls for adequate protection. In this study, structural responses of conventional offshore blast walls were investigated. A computation fluid dynamics (CFD) approach was used to predict effect of different explosions on the barrier walls and non-linear finite elements analyses were performed to study the behaviour of the blast-loaded walls under different explosions. Effect of different parameters related to blast wall and accidental explosions were investigated to gain detail understanding of structural behaviour of typical steel blast wall.
Diode Parameters of Heterojunctions Comprising p-Type Si Substrate and n-Type β-FeSi2 Thin Films
Authors: Promros Nathaporn , Funasaki Suguru , Takahara Motoki , Shaban Mahmoud , Yoshitake Tsuyoshi
Published: October 2014

n-Type β-FeSi2/p-type Si heterojunctions have been successfully fabricated by facing-targets direct-current sputtering at a substrate temperature of 600 °C without post-annealing and their current-voltage characteristics were measured at low temperatures ragne from 300 K down to 50 K. The ideality factor, saturation current and series resistance were estimated by the thermionic emission theory and Cheung’s method. By the thermionic emission theory, we calculated the ideality factor from the slope of the linear part from the forward lnJ-V and estimated the saturation current density from the straight line intercept of lnJ-V at a zero voltage. As decreasing temperatures from 300 down to 50 K, the value of ideality factor increased from 1.2 to 15.6, while the value of saturation current density decreased from 1.6 × 10−6 A/cm2 to 3.8 × 10−10 A/cm2. From the plots of dV/d (lnJ)-J and H(J)-J by Cheung’s method, the obtained values of series resistances are consistent with each other. The series resistances analyzed from both plots increased as decreasing temperatures.
Optimization of Multi-Pass Pocket Milling Parameter Using Ant Colony Optimization
Authors: Ab Rashid Mohd Fadzil Faisae , Harun W.S.W. , Ghani S.A.C. , Nik Mohamed N.M.Z. , Mohd Rose A.N.
Published: October 2014

In material removal process, milling is one of the oldest processes that were introduced to remove unwanted material using rotated cutting tool. Although a lot of research to improve the process has been done, the process improvement is not stopping there because of evolving new material, method and technology. This paper presents a study to optimize multi-pass pocket milling parameter using Ant Colony Optimization (ACO). Two objectives were set in this work; obtaining optimum surface roughness value (Ra), and minimize machining time (Tm), while the independent variables were spindle speed, feedrate and depth of cut. The numerical experiment confirm that the ACO is having better performance compare with other algorithms (including Genetic Algorithm) for this particular problem. Moreover, result from ACO algorithm able to meet required machining specification.
A Study of LiMn(2-X)FexO4 Cathodic Nano Material for Lithium-Ion Batteries
Authors: Fadzil A.F.M. , Muhammad F.H.
Published: October 2014

LiMn1.5Fe0.5O4is synthesized using sol-gel method and annealed at 850°C for 24 hours. It is then characterized using X-ray diffraction (XRD) and charge discharge analysis. The bulk material are then proceed to further grinding to become nanosize. The nanosample is then characterized using XRD and charge discharge performance, and the specific capacities of the two materials are compared. nanosample of LiMn1.5Fe0.5O4shows higher specific capacity which is 160.16 mAhg-1compares to the bulk which gives only 128.663mAhg-1. This shows that with smaller particle size, the battery performance has improved in terms of its capacity.
High Pressure Structural Phase Transition and Elastic Properties of Europium Chalcogenides
Authors: Sahu Ashvini K. , Aynyas M. , Bhardwaj R. , Sanyal Sankar P.
Published: October 2014

The high pressure induced structural phase transition and elastic properties of three Europium chalcogenides (EuX; X = S, Se, Te) have been studied using a two body potential approach. The calculated compression curves of EuS, EuSe and EuTe obtained so has been compared with recently measured three body potential data. The calculated transition pressures are in good agreement with the experimental data. The phase transition pressure for EuS, EuSe and EuTe going from the NaCl phase to CsCl phase have been observed are 22 GPa, 15 GPa, 10 GPa respectively, close the theoretical and experimental data. We have also calculated bulk modulas and second order elastic constants at high pressure which show partly ionic nature of theses compounds. The B1 (NaCl) phase is found to be higher in energy than the B2 (CsCl) phase and more stable at zero pressure.
First Principles Study of Electronic and Elastic Properties of AlY
Authors: Shugani Mani , Aynyas Mahendra , Sanyal S.P.
Published: October 2014

We have used full potential linear augmented plane wave method within thegeneralized gradient approximation to investigate the structural, electronic and elastic properties of the AlY. The ground state properties are determined for the AlY. The calculated ground state properties such as lattice constants, bulk modulus and elastic constants agree well with the experimental values. From band structure curves it is found that AlY is metallic in nature. The elastic constants are in good agreement with previous theoretical and experimental results.
Phonon Anomalies in Zirconium Nitride (ZrN)
Authors: Mishra Poonam , Aynyas Mahendra , Sanyal Sankar P.
Published: October 2014

The phonon dispersion curve is determined by model (BSM) for the crystals transition metal mono-nitride, Zirconium Nitride ZrN and compared with the experimental phonons, which forms perhaps the best test for this purpose. The eight numbers of parameters of the model are determined by using the some set of input data. The results and degrees of agreement obtained in each case show clearly the superiority of the “charge-transfer mechanism” for representing the deformations of electron shells used in the BSM. The phonon dispersion curve and phonon density of state ZrN have been measured in high-symmetry directions Δ, Σ and Λ by breathing shell model (BSM). Anomalies in the dispersion of the acoustic branches and optical branches have been detected which are well described by experimental results.
The Control and Simulation of the Live Washing Robot Based on the 6-DOF Manipulator
Authors: Tan Lin , Lu Shou Yin , Li Jian Xiang , Zhao Jin Long , Li Jian
Published: October 2014

Against the shortcomings of the live washing artificially, this paper puts forward a system about live washing robot, this system contains hydraulic system, video surveillance system, automatic regulatory system, communication system and motion control system. These subsystems can cooperate to complete live washing tasks. The operator commands manipulator and car from a cabin on the truck via a portable control box. In order to protect the operator, this system takes use of the wireless communication. This robotic system can finish the washing task perfectly instead of human. As for the inverse kinematic about the manipulator, this paper puts forward a new algorithm which is combined geometric method with algebraic method and confirms it’s correctness by simulation.
Aerodynamic Noise Reduction Analysis in High-Speed Train Cab
Authors: Zhang Xiao Feng , Xiao You Gang , Sun Liang , Shi Yu
Published: October 2014

In order to reduce aerodynamic noise in high-speed train cab,the SEA model of cab is established. The fluctuation pressures from train head surface are calculated by large eddy simulation method. Using fluctuation pressure as excitation force, power flow caused by airflow among sub-systems of SEA model of cab is obtained. Two schemes are put forward to reduce the aerodynamic noise in cab, namely interior decoration modification and windowpane thickness increase. The results show that when a layer of splint with 0.01 m thickness, 0.5 loss factor is added to the original decoration in cab, the overall sound pressure level (SPL) at driver head location will reduce 1.23 dB(A). When the cab windowpane thickness is increased to 5 mm from 4 mm, the overall SPL at the driver head location will reduce 0.87 dB(A).
Micro-Channel Mold Machined by Ultrafine WEDM
Authors: Wang Yu Kui , Chen Xiang , Zhu Bo , Wang Zhen Long
Published: October 2014

In this study, an ultrafine WEDM (wire electrical discharge machining) of micro-channel mold is proposed. It could be divided into two parts, rough machining and finish processing. In rough machining procedure, high machining voltage is adopted to improve machining efficiency. In finish machining procedure, extended and trimmed tool path is adopted to obtain the cusp at the corner, low electrical parameters is adopted to improve surface quality and dimensional precision. By conducting finish machining of 40V, a better surface-quality with Ra of 0.32μm and high aspect ratio of 20:1 was fabricated.
Research on the Optimal Design of Soccer Robot Based on the Mechanical Analysis
Authors: Xu Xue Xia , Li Wei Yong , Feng Yang Ting , Ke Hao , Zhang Guang Xing , Niu Xiao Guang , Wang Qing
Published: October 2014

Leakage causes of branch pipe of unit thermal networks were discussed based on macroscopic observation, chemical composition analysis, metallurgical microstructure inspection, mechanical property tests, SEM and EDS analysis. The experimental results showed that frequent contact of outer pipe wall with corrosion media and thermal fatigue load led to early crack of the pipe. During compression test, the crack propagated under increased compression stress and burst finally. Suggestions were provided to prevent similar events happening.
Design of Robust Control for Block Nonlinear Systems by Lyapunov Functions Method
Authors: Medvedev M. , Pshikhopov V.
Published: October 2014

This paper is devoted to robust control design for block multilinked nonlinear dynamical systems. Transformation of the block system to the single block system is proposed. For the considered block systems function of Lyapunov is designed. It is proved if the number of controls is equal to or more than the number of state variables of the block, then in the given area the closed-loop system conditions of stability followed controllability conditions. Control design accounts limitations of controls and state variables. Modeling results for nonlinear objects control systems are presented.
Study on the Sealing Property of Non-Asbestos Fiber Gasket
Authors: Li Yu Xian , Liu Mei Hong , Yuan Xi Chen , Jia You Dong
Published: October 2014

In recent years, Asbestos fibred gaskets are gradually replaced because of its serious health damage. Non-asbestos gasket is a heated discussion nowadays and the research of it will be of great significance. The present thesis firstly expounds the sealing principle of gasket, and then explains the main property index and its characterization method. Finally analyses and summarizes the main factors which we must consider to improve the sealing property of non-asbestos fiber gasket, and points out the main research ways of non-asbestos in the future.
Analysis of Kinematics and Dynamics of 3UPU/PU Parallel Platform Used in Automatic Wave Compensation
Authors: Lu Guang Can
Published: October 2014

3UPU/PU parallel platform is able to achieve a linear and two rotating motion (3-DOF ) platform,it can used in automatic wave compensation of ship deck equipment. The compensation platform is composed of dynamic and static plate, hydraulic cylinder and driven chain parts; it has strong capacity , simple structure and suitable for most conditions. This paper analysis the motion of the platform using one order and two order influence coefficient, establishes the dynamic model of this platform using the Newton Euler method , obtained the velocity, acceleration and force curve by simulating calculation, lay the foundation for the stable platform’s further dynamic analysis and control.
Compression Response of Sandwich Structure with M-Type CFRP Foldcore
Authors: Cong Li Xin , Sun Yu Guo
Published: October 2014

In order to solve the problem of the face/core bonding performance of the sandwich structure with chevron folded core, this paper proposed a M-pattern folded sandwich structure. Compression responses of fabricated folded cores were measured, and FE-analytical models were presented to predict the stiffness, strength and dominant failure modes under flatwise loading. The results show that the M-pattern folded sandwich structure has a high anti-buckling performance, and the dominant failure mode of the structure is crushing of the cell walls. The sandwich-panel cores investigated appear to be promising candidates for lightweight systems and multifunctional applications.
A Multi-Agent Based TE Process Simulation and Optimization Platform
Authors: Li X.Y.
Published: October 2014

For implementing the online control and simulation of TE process, a simulation and optimization platform is proposed based on multi-agent technology. Professional software such as G2, GAMS, Matlab, are wrapped as agents with multi-agent technology. Based on the simple object access protocol, it can control and optimize the online simulation procedure of TE process. Finally the practicability and validity of the proposed platform are verified through the application in the TE process simulation and optimization.
Modeling and Simulating of Frequency Conversion Soft Start System Based on SPWM
Authors: Song Yu Qian , Shi Shou Dong
Published: October 2014

Since over large starting current makes an instant giant grid voltage drop and contacting with current spark can damage the starting device when three phase asynchronous motor is directly started, in order to reduce the impact on the grid and the motor caused by the over large starting current, the present disclosure provides a frequency conversion soft start system based on SPWN. Control system generates IGBT controlled by SPWM pulse control using the regular sampling II method, thus achieving an AC infinitely approaching to a sine wave to open-loop control the motor and implement soft start. The method of frequency conversion soft start based on SPWM may implement a smooth start of the motor with lesser starting current and larger starting torque, thereby largely reducing the impact on the grid voltage and the motor. The experimental results showed that the method of frequency conversion soft start based on SPWM effectively reduces the starting current and implements the motor’s smooth start.
Automated Microinjection System Design and Experiments Based on Hybrid-Driven Micro-Robot
Authors: Qin Chuan Bo , Tian Lian Fang , Du Qi Liang , Zhang Qin
Published: October 2014

In order to resolve the operation difficulty, high cost problems of traditional manual cell microinjection, a low-cost microinjection system based on hybrid-driven micro-robot is presented. System is mainly composed of microscope, 3-DOF(degrees of freedom) micro-robot, signal generator and power amplifier. Firstly, we describe the automated microinjection system. Secondly, we analyze the motion performance of the robot in the horizontal and vertical direction. The single step resolution is less than 5um each step working at a frequency more than 200Hz. Maximum range of vertical motion is 5mm and minimum resolution ups to 2um. Finally, shrimp egg microinjection experiment is conducted using our system. The experimental result shows that this proposed scheme is simple, reproducible and can achieve microinjection success rate of 88%.