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61.
Micromachining is gaining popularity due to recent advancements in Micro Electro Mechanical Systems. Using conventional micromachining,
it is relatively difficult to produce moving components in the order of microns. In this study, an attempt is made to fabricate
microstructures using a combination of turning and electrodischarge machining (EDM). Several sets of experiments have been
performed to study the characteristics of the hybrid machining process. From the experiments, it has been observed that a
higher form of accuracy could be obtained by integrating the on-machine fabrication of the tool and by subsequently using
the same tool for EDM. The main cause of the form error is due to the deflection of the shaft during turning. Hence, an attempt
is made to observe the deflection of the shaft using a deflection sensor. The influence of micro-EDM parameters such as feed
rate, discharge circuits, and gap control parameters on material removal rate and tool wear is also discussed in this study. 相似文献
62.
K. Noel Jacob S. Senthil Kumar A. Thanigaivelan M. Tarun D. Mohan 《Journal of Materials Science》2014,49(1):114-122
Membranes are being increasingly used as an economic alternative for wastewater treatment compared to conventional methods. Ultrafiltration membranes are widely used in metal ions’ rejection. Sulfonated Polyethersulfone (SPES)/polysulfone (PSf) blend flat sheet membranes are prepared using polar solvent N-methyl-2-pyrrolidone (NMP) by the dry–wet phase inversion technique. Polyethylene glycol (PEG-200) is used as a non-solvent additive in the casting solution. The effect of PSf/SPES blend ratio on the morphology, hydrophilicity, water content, porosity, hydraulic resistance, pure water flux, compaction, and molecular weight cut-off (MWCO) of the prepared membranes was studied and found to be improved significantly by the incorporation of SPES in the dope solution. Scanning electron microscopy (SEM) studies revealed that the membranes formed had an asymmetric structure with a thin skin layer and porous sublayer. The prepared membranes were used for rejection of Cu(II) and Zn(II) which are complexed with water-soluble chelating polymer polyethyleneimine. The results show that the order of rejection is Cu(II) ion > Zn(II) ion. Thus, it is worth mentioning that the PSf/SPES blend ultrafiltration membranes prepared in this study would offer immense potential in removal of toxic metal ion from industrial effluents. 相似文献
63.
M. Raja N. Muthukumarasamy Dhayalan Velauthapillai R. Balasundraprabhu S. Agilan T. S. Senthil 《Journal of Materials Science: Materials in Electronics》2014,25(11):5035-5040
Aluminium doped and copper doped ZnO nanostructured thin films have been prepared using simple solgel dip coating method. The X-ray diffraction pattern results revealed that the prepared Al and Cu doped ZnO sample exhibits hexagonal structure. The average crystallite size of pure ZnO, Al doped ZnO and Cu doped ZnO samples were found to be 29, 26 and 15 nm, respectively. The optical band gap of ZnO, Al doped ZnO and Cu doped ZnO thin films was found to be 3.27, 3.29, and 3.20 eV respectively. Solar cells have been fabricated using CdS quantum dots sensitized ZnO nanostructured thin films and the efficiency of the fabricated Al doped and Cu doped ZnO solar cells were 1.37 and 1.29 % respectively. 相似文献
64.
This paper describes the electrocatalytic activity of quantum-sized thiolate protected Au(25) nanoparticles and their use in electrochemical sensing. The Au(25) film modified electrode exhibited excellent mediated electrocatalytic activity that was utilized for amperometric sensing of biologically relevant analytes, namely, ascorbic acid and uric acid. The electron transfer dynamics in the Au(25) film was examined as a function of Au(25) concentration, which manifested the dual role of Au(25) as an electronic conductor as well as a redox mediator. The electron transfer study has further revealed the correlation between the electronic conductivity of the Au(25) film and the sensing sensitivity. 相似文献
65.
Nano finish grinding of brittle materials using electrolytic in-process dressing (ELID) technique 总被引:4,自引:0,他引:4
Recent developments in grinding have opened up new avenues for finishing of hard and brittle materials with nano-surface finish,
high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface finish.
However, superabrasive diamond grits need higher bonding strength while grinding, which metal-bonded grinding wheels can offer.
Truing and dressing of the wheels are major problems and they tend to glaze because of wheel loading. When grinding with superabrasive
wheels, wheel loading can be avoided by dressing periodically to obtain continuous grinding. Electrolytic inprocess dressing
(ELID) is the most suitable process for dressing metal-bonded grinding wheels during the grinding process. Nano-surface finish
can be achieved only when chip removal is done at the atomic level. Recent developments of ductile mode machining of hard
and brittle materials show that plastically deformed chip removal minimizes the subsurface damage of the workpiece. When chip
deformation takes place in the ductile regime, a defect-free nano-surface is possible and it completely eliminates the polishing
process. ELID is one of the processes used for atomic level metal removal and nano-surface finish. However, no proper and
detailed studies have been carried out to clarify the fundamental characteristics for making this process a robust one. Consequently,
an attempt has been made in this study to understand the fundamental characteristics of ELID grinding and their influence
on surface finish. 相似文献
66.
T. Senthil Kumar V. Balasubramanian S. Babu M. Y. Sanavullah 《Metals and Materials International》2007,13(4):345-351
AA6061 aluminium alloy (Al−Mg−Si alloy) has gathered wide acceptance in the fabrication of food processing equipment, chemical
containers, passenger cars, road tankers, and railway transport systems. The preferred process for welding these aluminium
alloys is frequently Gas Tungsten Arc (GTA) welding due to its comparatively easy applicability and lower cost. In the case
of single pass GTA welding of thinner sections of this alloy, the pulsed current has been found beneficial due to its advantages
over the conventional continuous current processes. The use of pulsed current parameters has been found to improve the mechanical
properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the
fusion zone. In this investigation, an attempt has been made to develop a mathematical model to predict the fusion zone grain
diameter incorporating pulsed current welding parameters. Statistical tools such as design of experiments, analysis of variance,
and regression analysis are used to develop the mathematical model. The developed model can be effectively used to predict
the fusion grain diameter at a 95% confidence level for the given pulsed current parameters. The effect of pulsed current
GTA welding parameters on the fusion zone grain diameter of AA 6061 aluminium alloy welds is reported in this paper. 相似文献
67.
Hariharan Ramalingam Bhuvana Sowrirajalu Anuradha Ganesan Sarojadevi Muthusamy 《Polymer International》2004,53(10):1442-1447
A new type of diamine monomer containing the anisyl moiety was synthesized via a straight‐forward one‐step procedure. Anisaldehyde was reacted with 2,6‐dimethylaniline in the presence of dry HCl to attain bis(4‐amino‐3,5‐dimethylphenyl)anisylmethane. A series of organo‐soluble polyimides were prepared using the anisyl diamine and various aromatic dianhydrides via a two step method involving thermal imidization. All polyimides are soluble in strong polar solvents such as N‐methyl‐2‐pyrollidone, N,N‐Dimethylformamide, and N,N‐DimethylAcetamide. The polyimides show excellent thermal stability and good mechanical properties. The glass transition temperatures of the polyimides are in the range 265–294 °C. The tensile strengths are in the range 79–99 MPa and the temperatures at which 10 % weight loss occurs are in the range 460–496 °C. Copyright © 2004 Society of Chemical Industry 相似文献
68.
M. Azizur Rahman M. Rahman A. Senthil Kumar H.S. Lim A.B.M.A. Asad 《The International Journal of Advanced Manufacturing Technology》2006,27(9-10):939-944
A micropin fabrication process has been developed based on micromachining technology. One group of micromachining technology is microturning. It has the capability to produce three dimensional features on the micro scale. This paper deals with the CNC microturning process. Basically two types of microturning processes are used: straight microturning and taper microturning. Experiments were performed using a programmable multi-purpose miniature machine tool developed for tool based micromachining. NC codes were generated using Borland C++ Builder 6.0. Brass bars of 6 mm diameter have been machined to fabricate the micropin with carbide cutting tools. Work materials were clamped on the spindle which has the facility of three-axis movements. Unlike the conventional processes, the cutting tool has no movement. A step cutting process was applied to eliminate workpiece deflection in the microturning process. Finally a micropin was fabricated with 2 mm length. The larger and smaller diameter of the pin are 475 μm and 276 μm, respectively. 相似文献
69.
Phuong H. Hoang Anand Gangadharan Suresh C. Ramalingam 《Nuclear Engineering and Design》1998,181(1-3)
The Palisades nuclear plant has developed a comprehensive inspection program to support safe, reliable, and cost-effective operation of all Alloy 600 nozzles and safe ends in the primary coolant system (PCS). As a part of the Palisades Alloy 600 Project, an inspection prioritization scheme was developed to help the plant focus its resources on high-risk components and plan appropriate inspection activities for the other components. The inspection prioritization scheme is based on the susceptibility of the components to primary water stress corrosion cracking (PWSCC), component failure consequences, component leak detectability and component radiation exposure. The scheme provides a simple, systematic and technical base for selecting Alloy 600 components for inspection. The scheme, however, could be used to develop an inspection schedule or to select the highest priority components for mitigation or replacement. 相似文献
70.
Summary The monomer, N-4'-fluorophenylmethacrylamide (FPMA) was polymerized for the first time using benzoyl peroxide as the initiator. The IR and NMR spectra of FPMA and the polymer, poly(N-4'-fluorophenylmethacrylamide) (PFPMA) are discussed. Viscosity measurements of PFPMA was carried out in dimethylformamide medium at 25°C. The number average molecular weight of PFPMA was determined to be 690 using vapour pressure osmometer. The formation of low molecular weight of PFPMA is explained on the basis of intermolecular hydrogen bonding in the monomer. 相似文献