bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification in Hygroscopic Nature of Urea via Formation of Solid Solution, and its Particle Size and Second Harmonic Generation Study
Authors: Bhimireddi Rajasekhar , Rai Ramanand
Published: October 2012

Solid solution of m-dinitrobenzene (DNB) and 4-bromo-2-nitro aniline (BNA) in urea (U) were prepared based on the prior study of phase diagram. The formation of solid solution was studied using the powder X-ray diffraction techniques. The powder X-ray data were also used for the study of particle size and strain in solid solution. The vapor sorption and desorption studies revealed that the hygroscopic character of urea was modified in solid solution. The study for the second harmonic generation efficiency of urea, DNB, BNA and the solid solution was done with fundamental of Nd:YAG laser (1064 nm).
Studies on Thin Film Oxide Formation on GTA Welded AISI 304 & AISI 310S Exposed at 600°C
Authors: Kesharwani Jeet Kumar , Paliwal Abhilash , Kothari Kamir , Ramkumar K. Devendranath , Arivazhagan N. , Narayanan S.
Published: October 2012

In this research work, an attempt was made to study the thin film oxide formation on the dissimilar gas tungsten arc welded austenitic stainless steels of grades AISI 304 and AISI 310S using E309L filler wire. These combinations are widely used in power plant and marine applications. An assessment was carried out to estimate the metallurgical, mechanical properties of the weldment. Tensile tests revealed that the fracture occurred at the weld zone. In addition, Vickers Micro-hardness tests were performed across the length of the weldment. Furthermore, hot corrosion studies were performed on different regions (heat affected zones, weld zone and parent metal zones) of the weldment subjected to air oxidation at 600°C. It was revealed from thermogravimetric analysis that there was weight loss in the heat affected zone of the AISI 310S side after 50 cycles. The thin film oxide layer formation on various zones of the weldment was examined using the combined techniques of optical microscopy, XRD and SEM/EDAX analysis.
High-Temperature Electrical Transport Property of Misfit Cobaltite of Ca3-xNdxCo4-xCuxO9 (x = 0.0 – 0.4)
Authors: Senthilkumar M. , Vijayaraghavan R.
Published: October 2012

Polycrystalline samples of the Ca3-xNdxCo4-xCuxO9 (x = 0.0 - 0.4) were prepared by the sol-gel cum combustion method using sucrose to investigate the effects of the coupled substitution of Nd and Cu on Ca and Co sites simultaneously on electrical property of Ca3Co4O9 (Co349). The products were characterized by powder x-ray diffraction (XRD), thermogravimetry (TG) / differential thermal analysis (DTA) and scanning electron microscopy (SEM). Powder XRD patterns reveal the formation of single-phase products up to x = 0.4. Coupled substitution increases the solubility of Cu on Co site, in contrast to the limited solubility of Cu (x = 0.3) when separately substituted. TGA confirms the formation of the Ca3Co4O9 phase at around 680 0C. The grain size of the parent and substituted products is in the range of 200-250 nm. Electrical resistivity (ρ) measurement was performed in the temperature range of 300 - 800 K. Electrical resistivity (ρ) of parent sample shows metallic type conduction behavior up to 500 K and above 500 K, it shows semiconducting behavior. All the substituted compositions show semiconducting behavior with increasing electrical resistivity with increasing x. The conduction mechanism was also analyzed. Parent and substituted samples behave thermally activated conduction mechanism in the temperature range of 600 – 800 K.
Activated Carbon - Mn3O4 Nanocomposites – Synthesis and Magnetic Studies
Authors: Ranjithkumar V. , Vairam S.
Published: October 2012

Keywords: Activated carbon; Nanocomposites; Mn3O4; Saturation magnetization Abstract: Activated carbon-Mn3O4 nanocomposites have been prepared by in situ decomposition of metal carboxylates into activated carbon matrix using acetate and benzoate of manganese as precursor for metal oxide. The morphology and size of the Mn3O4 particles inserted into activated carbon matrix have been investigated by IR, XRD, Scanning electron microscope and Transmission electron microscope. The magnetic nature of composites has been investigated by Vibrating Sample Magnetometer.
Effect of Thermal Cycling on the Ferroelectric Characteristics of Vinylidene Fluoride-Trifluoroethylene Copolymer Thin Films
Authors: Sathiyanathan P. , Manjula Dhevi Dhevagoti , Prabu Arun Anand , Kim Kap Jin
Published: October 2012

Thin films of polyvinylidene (PVDF) and its copolymers containing 50 to 30 mole % of trifluoroethylene (TrFE) demonstrate rapid reversal of polarization under applied electric field, and can be used as ferroelectric materials in non-volatile memory devices. In this study, Fourier-transform infrared transmission (FTIR-TS) and grazing incident reflection absorption (FTIR-GIRAS) spectroscopy techniques were used to examine the changes in Curie transition temperature (Tc), chain and dipole orientation in selected VDF copolymer spun-cast films as a subjected to a reversible thermal-cycling treatment. A reversible solid-to-solid β-crystalline phase transition with thermal hysteresis and a favorable C-F dipole orientation along the electric field direction were observed for the sample subjected to thermal-cycling below its melting point (Tm). An irreversible β-crystalline phase transition with unfavorable C-F dipole orientation was observed for the sample treated to heating-cooling cycle above Tm. The results are reported in detail here.
Nanostructured Hydroxyapatite-Chitosan Composite Biomaterial for Bone Tissue Engineering
Authors: Venkatesan Jayachandran , Kim Se Kwon
Published: October 2012

In the recent years, significant developments have been achieved with chitosan and hydroxyapatite (HAp) scaffolds for bone tissue engineering. In the present study, chitosan/nanostructured hydroxyapatite (Chitosan/nHAp) has been prepared and subsequently characterized physicochemically for bone graft substitution. The nano sized HAp particles were uniformly distributed in the chitosan matrix which was confirmed by Fourier Transform Infrared Spectroscopy, Thermal Gravimetric Analysis, X-Ray Diffraction and Scanning Electron Microscopy analysis. The pore size of the chitosan/nHAp scaffold was found to be 18-372 µm which is suitable for cell attachment and nutrient supplement. Thus, we are suggesting that Chitosan/nHAp could be promising biomaterials for bone tissue engineering.
Blue Fluorescence in Doped LaF3 Nanocrystals Synthesized by Microwave Technique
Authors: Gaurkhede S.G. , Khandpekar M.M. , Pati S.P. , Singh A.T.
Published: October 2012

Hexagonal-phase LaF3: Ce3+, Pr3+, and Sm3+ doped (LCPS) nano-crystals have been synthesized by keeping same molarities of rare earth elements using aqueous route. The samples have been synthesized in conventional microwave on low power range in about an hour’s time. The phase formation has been verified by powder X-ray diffraction (XRD).Hexagonal geometry of the LCPS nano-crystals has been observed with an average particle size of 20 nm by TEM analysis. The JCPDS Card No. (32-0483) and selected area electron diffraction (SAED) pattern has been used for identification of crystal structure. The UV- VIS spectra indicated band gap of 5.00eV. The FTIR spectrums have been used for assignment of fundamental vibrations. Blue fluorescence observed with exciting wavelengths of 254 nm respectively. The presence of rare-earth elements in LCPS nano-crystals have been verified by the EDAX spectra.
Preparation and Characterization of Ag and Co Doped ZnO Nano Particles
Authors: Sankara Reddy B. , Venkatramana Reddy S. , Vijaya Lakshmi R.P. , Koteeswara Reddy N.
Published: October 2012

Pure ZnO and Ag, Co doped ZnO nano particles [Zn1-xAgxCoyO, where x = 0.00 and 0.05, y = 0.05] were synthesized by chemical co precipitation method without use of surfactant. All the prepared samples calcinated in 1 hour at 500oC, after that the morphology of the samples were evaluated by Scanning Electron Microscope (SEM). The X- ray diffraction (XRD) results indicated that the synthesized co-doped ZnO nano crystals had the pure hexagonal structure without any significant change in the structure affected by Ag and Co substitution. Dopant elements Ag and Co are present in the ZnO host material and conformed by Energy Dispersive Analysis of X-ray Spectra (EDAX). The incorporation of Ag+ in the place of Zn2+ has made a considerable decrease in the size of nano crystals as compared to pure ZnO nano particles (It is to be noted that Co should be kept constant at 5 mol %). Blue emission was observed by Photo Luminescence (PL) Spectra.
Synthesis, Characterization and Electrochemical Sensing Property of Fe-Fe2O3 Nanocomposite
Authors: Manigandan R. , Suresh R. , Giribabu K. , Vijayalakshmi L. , Stephen A. , Narayanan V.
Published: October 2012

Fe-Fe2O3 nanocomposite was synthesized by one pot method using ferric chloride as the iron source, sodium borohydride as the reducing agent and PVA as the stabilizer. The synthesized Fe-Fe2O3 nanocomposite was characterized by using XRD and SEM. The XRD studies reveal the formation of Fe-Fe2O3 nanocomposite and the broadening of the peak reveals the narrow size distribution of the Fe-Fe2O3 nanocomposite. The SEM image of Fe nanocomposite shows the agglomerated microspheres. The synthesized Fe-Fe2O3 composite nanoparticles were evaluated for electrochemical sensing of hydrogen peroxide. The electrochemical behaviour of Fe-Fe2O3 nanocomposite modified glassy carbon electrode (GCE) exhibit excellent electrocatalytic activity when compared with bare GCE.
Dielectric Behavior and A. C. Conductivity Studies on Nickel Nanoferrites Synthesized by Solution Combustion Method
Authors: Madhu B.J. , Angadi V. Jagadeesha , Mallikarjuna H. , Manjunatha S.O. , Shruthi B. , Madhu Kumar R.
Published: October 2012

Nanoscale Nickel ferrite particles were prepared by combustion method using nickel nitrate as oxidizer and urea as a fuel. The structure of the sample is studied with X-ray diffraction (XRD) using Cu-Kα radiation. The X-ray diffraction analysis revealed the nanocrystalline nature in the prepared ferrite samples. Dielectric studies have been undertaken over a wide range of frequencies (100Hz-5MHz) for Nickel nanoferrites at room temperature. Dielectric properties such as dielectric loss tangent (D), dielectric constant (ε′ ) and dielectric loss factor (ε″) are found to decrease with the increase in the frequency. Observed variations are understood on the basis of Koop’s phenomenological model. Further, a. c. conductivity of the Nickel nanoferrite was found to increase with the increase in the frequency. Observed variation in the a. c. conductivity with the frequency has been understood on the basis of electron hopping model.
The Improved Behavior of Gd Substituted BaCeYO3 Nanocomposites for IT-SOFC Electrolytes
Authors: Kattamanchi Sruthi , Vasudevan Rathinam , Jayavel Ramasamy , Ganesan Singaravelu
Published: October 2012

The Gd substituted BaCe0.8Y0.1O3-δ nanocomposites were prepared by a modified Pechini route and then the prepared material was subjected to conventional sintering at 1400°C. The powder XRD results show that the material exhibit orthorhombic crystalline structure and the mean particle size were calculated to be ~40 nm. SEM micrographs indicate that the particle sizes were observed in the nanometer range with dense microstructure, which leads to increase in the densification of the material. FT-IR result confirms the presence of metal bondings in the material. DTA peaks observed at 725°C and 880°C show the crystallization of the material and the corresponding weight loss was recorded in the TG spectrum. I-V & I-P results show that the maximum open cell voltage (OCV) was measured at 1.1V and the maximum power density of about 801mWcm2 was observed which may be due to the substitution of Gd ions into the BaCeYO3 sites showing an improved electrochemical performance of IT-SOFC electrolytes.
Electrochemical Detection of Hydrazine Using Cobalt Hexacynoferrate Deposited Carbon Sphere Modified Glassy Carbon Electrode
Authors: Marimuthu Alexander , Pandian Kannaiyan
Published: October 2012

Cobalt hexacynoferrate decorated carbon spheres (CoHCF@C) with few micron dimensions was synthesized by sequential deposition method in which the carbon sphere previously modified with cobalt ion exposed into potassium ferricyanide. The thickness of the CoHCF layer was restricted to five cycles. The formation of layer CoHCF was confirmed by FT-IR, XRD, HRSEM, EDX and cyclic voltammeter technique. The CoHCF decorated carbon sphere modified GCE was utilized as electron transfer mediator for electrocatalytic oxidation of hydrazine in phosphate buffer medium. The electrocatalytic behavior of modified electrode on oxidation of hydrazine is compared with bare GCE. The amperometry method was adapted for the quantitative detection of hydrazine in water samples.
Electrochemical Sensor for the Detection of Dopamine in the Presence of Ascorbic Acid in Neutral pH on Graphitized Nanoporous Carbon Modified Glassy Carbon Electrode
Authors: Thangaraj Rajendiran , Mufeedah Muringah Kandy , Kumar Annamalai Senthil
Published: October 2012

Selective detection of dopamine (DA) in presence of ascorbic (AA) is an important analytical problem, due to its combined existence in the biological system. In the present study, we are reporting an electrochemical detection method for dopamine (DA) in the presence of ascorbic acid (AA) using graphitized nanoporous carbon (NPC) modified glassy carbon electrode (GCE/NPC) in 0.1 M phosphate buffer solution. The modified electrode shows excellent electrocatalytic activities towards the oxidations of DA and AA in neutral pH buffer solution. Compared to unmodified GCE, GCE/NPC shows well separated and enhanced oxidation peak currents. Differential pulse voltammetric technique used as qualitative analytical tool for the detection of DA. The oxidation peak potentials for DA and AA were at -80 and 136 mV vs Ag/AgCl respectively. The modified electrode shows good stability and reproducibility with the relative standard deviation value of 2.6 %. The analytical application of the modified electrode (GCE/NPC) was demonstrated for the individual determination of DA in clinical injection and pharmaceutical tablet by using standard addition method.
Synthesis and Characterization of Cu Doped LiCoO2 Cathode Material for Lithium Batteries Using Microwave Assisted Sol-Gel Synthesis
Authors: Prahasini P. , Sivakumar Marimuthu , Subadevi Rengapillai , Wang Fu Ming
Published: October 2012

LiCoO2 is the most studied cathode material for lithium batteries. The doping effect gives a better cycle life in such materials. Apart from the doping effect, the preparation technique also plays an important role. Presently, the layer structured Cu doped LiCoO2 cathode material has been prepared via microwave assisted sol gel route; better cycle life and capacity retention have been attained. It was found that this method could reduce the synthesis time to 30 minutes. The espousal of the microwave method in synthesis could develop a highly efficient, low cost process for synthesis. The surface morphology of the material has been observed using SEM and it is inhomogeneous in nature. The capacity retention is higher than that of pure LiCoO2 material. Compositional analysis was made through EDX. The Cu doped material has a voltage plateau about 4.0V which is obtained from the cyclic voltammetry.
A Study on Topology of Lateral Surface of Components Manufactured by Selective Laser Sintering
Authors: Naiju C.D. , Adithan M. , Radhakrishnan P. , Annamalai K.
Published: October 2012

This work presents the results of a study carried out to determine the topology of lateral surface and its effect on the process parameters of components manufactured by selective laser sintering (SLS). Using Taguchi’s experimental technique, an orthogonal array of L4 had been developed. Surface roughness was measured along built direction and analysis of variance (ANOVA) technique was used to investigate the effect of process parameters and to identify main process parameter that influences surface roughness on SLS components. It has been found that slice thickness and scan spacing have more significant influence than the laser power. Microstructure of the sintered specimen along the build direction was studied using Scanning Electron Microscope (SEM). It was observed that variations in slice thickness affect surface topology of SLS components.
Photocatalytic Degradation of Organic Dyes Using ZnO/CeO2 Nanocomposite Material under Visible Light
Authors: Saravanan R. , Karthikeyan N. , Govindan S. , Narayanan V. , Stephen A.
Published: October 2012

Nanorods of ZnO/CeO2 were synthesized by thermal decomposition method. The decomposition temperature and formation of composite material were confirmed by the thermogravimetric analysis (TGA) before the synthesis process. The prepared samples were characterized by different techniques. The structural and morphological properties of ZnO/CeO2 nanorods were confirmed by X-ray diffraction (XRD) and high resolution scanning electron microscopy (HR-SEM). The chemical composition and specific surface area analysis were done by energy dispersive X-ray spectroscopy (EDX) and Brunauer–Emmett–Teller (BET) method. Further the catalyst was used for photocatalytic degradation of organic dye under visible light irradiation
Synthesis, Spectral, Electrochemical, Magnetic and Biological Studies of Tet-A Based Binuclear Mn(III) Complexes
Authors: Prabu R. , Vijayalakshmi L. , Narayanan V.
Published: October 2012

A new phenoxo-bridged Tet-a based binuclear manganese(III) complexes were synthesized by the Schiff base condensation reaction of the compound 1,8–[bis(3-formyl-2-hydroxy-5-methyl)benzyl] -5,5,7,12,12,14- hexamethyl -l,4,8,11-tetraazacyclotetradecane (PC–a) and 1,8– [bis(3-formyl-2-hydroxy-5-bromo)benzyl]- 5,5,7,12,12,14-hexamethyl-l,4,8,11-tetraazacyclotetradecane (PC–b) with triethylenetetramine and manganese(II) perchlorate hexahydrate. Their synthesized complexes were confirmed by analytical and spectral analysis. The phenolate oxygen atom is acting as bridge between two unsymmetrically coordinated Mn atoms. Electrochemical studies of the complexes reveal that all the redox processes are irreversible in nature. Low temperature magnetic study shows that the complexes exhibit antiferromagnetic exchange interaction between the two metal ions. The spectral and magnetic behavior of the complexes is discussed.
Synthesis and DNA Binding Study of Zinc (II) Co-Ordination Complexes
Authors: Inamdar Poonam R. , Hazarika Jyotsna , Sridharan T.B. , Sheela A.
Published: October 2012

Since the discovery of cisplatin, transitional metal complexes have been proven to be potent DNA intercalating agents. As zinc being an active core of binding site of some metalloenzymes, the synthesis of structurally similar zinc (II) complexes is on the offing. They are found to be potent DNA intercalating and cleaving agents. Thus, the current study is focused on synthesis of zinc (II) complexes using amino acid / schiff bases as ligands. The complexes are characterized by FTIR, UV-Visible and mass spectral studies and assessed for their DNA binding study using λ DNA by Gel electrophoresis.
Alkoxyalkanol Modified Ti(OCHMe2)4: Synthesis and Characterization of Novel [(OPri)4-nTi (OC2H4OR)n]
Authors: Pathak Madhvesh , Samuel Blassan , Tummalapalli Kiran , Vuppalapati Giri Prasanth , Koppala Sivasankar , Bohra Rakesh , Kim Kap Jin
Published: October 2012

Novel structural arrangements for alkoxyalkanol modified titanium tetraisopropoxide [(Ti(OPri)4, TPT] were obtained from stoichiometric reactions between TPT and alkoxyalkanols {HOCH2CH2OR,where R= Me, Et}. All the 1:1, 1:2, 1:3 and 1:4 reactions in refluxing benzene form mononuclear species [(OPri)4-nTi(OC2H4OR)n]. All these compounds can be purified by distillation under reduced pressure. On the basis of IR and NMR (1H &13C) spectral studies all the mononuclear derivatives have been obtained in tetrahedral geometry around titanium atom.
A Theoretical Investigation on the Dimensions and Annealing Effects of InAs/GaAs Quantum Dots for Device Applications at High Bit-Rate Optical Transmission Window of 1.3-1.55 μm
Authors: Ghosh K. , Naresh Y. , Reddy N. Srichakradhar
Published: October 2012

In this paper, we present theoretical model and computations for tuning the photoluminescence (PL) emission of InAs/GaAs quantum dots at 1.3 -1.55 μm by optimizing its height and base dimensions through quantum mechanical concepts. Simulation on the annealing induced compositional change in the QDs was carried out using Fick’s diffusion model. Results from our computation illustrated that lower base size of 10 nm and larger height QDs of 5.1 nm can be effectively utilized for extending the PL emission to longer wavelengths with minimal blue-shift on annealing. This highlights the potential of our model and computation to assist in precisely engineering the optical properties of QD materials for specific device applications.
First Principle Study of Tunnel Currents through CeO2, Y2O3, TiO2 and Al2O3 Dielectrics in MOSFETs for Ultra Large Scale Integration
Authors: Chakraverty Mayank , Kittur Harish M.
Published: October 2012

High gate leakage current, as a central problem, has decelerated the downscaling of minimum feature size of the field effect transistors In this paper, a combination of density functional theory and non equilibrium Green’s function formalism has been applied to the atomic scale calculation of the tunnel currents through CeO2, Y2O3, TiO2 and Al2O3 dielectrics in MOSFETs. The tunnel currents for different bias voltages applied to Si/Insulator/Si systems have been obtained along with tunnel conductance v/s bias voltage plots for each system. The results are in agreement to the use of high dielectric constant materials as gate dielectric so as to enable further downscaling of MOSFETs with reduced gate leakage currents thereby enabling ultra large scale integration. When used as dielectric, TiO2 exhibits extremely low tunnel currents followed by Y2O3 while CeO2 and Al2O3 exhibit high tunnel currents through them at certain bias voltages.
Biodegradable Amphiphilic Tri-Block Copolymeric Nanoparticles for Controlled MTB Drug Delivery
Authors: Gajendiran M , Balasubramanian S.
Published: October 2012

. A series of biodegradable amphiphilic tri-block copolymers (PLGA–PEG–PLGA) have been derived from the diblock copolymer poly (lactic–co–glycolic acid (PLGA)) and polyethylene glycol (PEG). The mycobacterium tuberculosis (MTB) drug pyrazinamide (PZA) loaded polymer nanoparticles (NPs) have been prepared by probe-sonication followed by w/o/w double emulsification technique. The copolymers have been characterized by FTIR and 1HNMR spectroscopic techniques, TG-DTA analysis, GPC analysis and powder XRD pattern. The MTB drug loaded polymeric NPs have been characterized by FESEM, powder XRD, HRTEM and XPS analysis. The drug loading efficiency, drug content and in vitro drug release studies have been carried out by spectrophotometry. The drug loading efficiency and drug content of triblock copolymeric NPs were higher than these of diblock copolymeric microparticles (MPs). The in vitro drug release studies indicate that the NPs exhibit initial burst release followed by controlled release of PZA for longer durations. The drug release kinetics mechanism has been evaluated by zero order, first order, Korsemeyer-Peppas (KP) and Higuchi models.
PLGA Nanoparticles for Anti Tuberculosis Drug Delivery
Authors: Malathi S. , Balasubramanian S.
Published: October 2012

Nanoparticles-based drug delivery systems have considerable potential for the treatment of tuberculosis (TB). A series of PLGA polymers with different molar feed ratios (P2:87/13, P3:83/17, P5:63/37, P6:76/24, P9:53/47) were synthesized by direct melt poly condensation method. The resulting biodegradable polymers were characterized by FTIR and 1H NMR spectroscopy. The preparation of the drug (Pyrazinamide (PZA)) encapsulated PLGA polymers were carried out by double emulsion – solvent evaporation technique. The drug loaded PLGA-NPs were analyzed by UV-visible spectroscopy and scanning electron microscopy. The drug loading efficiency and drug release kinetics varies in the following order: P9>P5>P6>P3>P2. Among the formulations, PP9 showed a uniform as well as sustained drug release. The drug release kinetics has been evaluated by Zero-order, First order, Higuchi and Koresmeyer- Peppas models and the release mechanism has also been investigated
Dielectric Behavior of Calcium Oxalate Monohydrate Urinary Stone
Authors: Mohamed Ali Abdul Rasheed , Arunai Nambi Raj Narayanasamy
Published: October 2012

Calcium oxalate is the most significant component of urinary stones, usually in its monohydrate form. The mechanisms for the formation of calcium oxalate urinary stones are still not understood, though it is thought that organic macromolecules play a significant role. Calcium oxalate monohydrate (COM) urinary stone was subjected to dielectric studies in order to understand the formation and growth of the renal stones in vivo and use them to help in the treatment procedures for more effective stone fragmentation. The chemical composition and the crystalline nature were verified using Fourier Transform Infrared spectroscopy, X-ray diffraction and thermal analysis. The dielectric parameters for the COM renal stone namely, capacitance, dielectric loss coefficient, impedance, and resistance were measured at room temperature and hence the dielectric constant and the alternating current conductivity were calculated in the frequency range 200 Hz to 5 MHz. The measured values and the dielectric constant showed systematic variations up to 10 kHz. The alternating current conductivity was almost constant up to 2.0 kHz and then showed systematic increase at around 100 kHz and reaches a maximum value at around 5 MHz. The results may be used in further studies of renal stones about their formation and growth.
Demographic Study of Water Hardness with Potential to Predict Formation of Renal Crystals
Authors: Chatterjee Deeptiman , Verma Vishaka , Amiti  , Rohil Sheija , Arunai Nambi Raj Narayanasamy , Vidya R.
Published: October 2012

Kidney stones or renal calculi or Nephrolithiasis is a common health problem in both developed and developing nations [1,2]. Analysis of the chemical and physical properties of renal calculi helps in preventing their formation and treatment. In this study, we evaluated the hardness of water used for drinking purposes, in an attempt to correlate water hardness with an increased incidence of stone formation. Identifying risk factors help to develop a preventive strategy to reduce the risk of renal calculi formation. The incidence of kidney stone formation in Vellore district was correlated with the hardness of water samples taken from different areas in Vellore. The study can be employed at a larger demographic level for effective and economic monitoring of the risk of kidney stone formation.
Effect of Vibratory Treatment on Hot Cracking Resistance in AA6061 Alloy
Authors: Balasubramanian Kaliyaperumal , Balusamy V.
Published: October 2012

AA6061 alloy is most widely used in aircraft fittings, marines fitting and automobile industries. This alloy can be joined by fusion welding process like Gas Tungsten Arc Welding (GTAW). An important metallurgical difficulty in arc welding of this alloy is hot cracking. As the name indicates, this kind of cracking occurs while the metal is still hot. It usually occurs in the fusion zone during solidification. The main aim of this work is to investigate the effect of vibratory treatment on hot cracking of AA6061 alloy. Houldcroft hot cracking test is used to determine the hot cracking tendency. Weld bead was made on AA6061 alloy specimen in the presence and absence of vibratory treatment. Vibratory treatment was carried out in the frequency range of 250 Hz to 900 Hz. Weldments made with and without vibratory treatment were compared using hot cracking tests. Test results show that by applying vibratory treatment, hot cracking can be largely controlled in AA6061 alloy.
Study of Degenerate Four-Wave Mixing in Disperse Orange Dye-Doped Polymer Film
Authors: Aithal Shubhrajyotsna , Aithal P. Sreeramana , Bhat Gopalkrishna
Published: October 2012

Nonlinear optical phase conjugation by degenerate four-wave mixing (DFWM) is an important technique with applications in many fields of science and technology. Phase conjugation by Degenerate four-wave mixing is observed in Disperse Orange-25 dye doped in Polymethyl methacrylate – metacrylic acid (PMMA-MA) polymer film under low-power, continuous-wave laser irradiation. A maximum phase conjugate efficiency of 0.22% has been obtained for probe beam intensity at 0.11 W/cm2. Phase conjugation is observed for both parallel- and orthogonally-polarized probe and pump beams. The maximum PC reflectivity is achieved when the angle between probe and forward pump beam is 7 degrees. The effects of dye concentration, intensity of backward, forward pump and inter beam angle between probe and forward pump beam on phase conjugation reflectivity are also studied. PC signal strength first increases and then decreases. PC reflectivity is increased by increasing the intensity of the backward and forward pump beam. The polarization and intensity profile are verified to be preserved in the conjugate signal. The predominant phase conjugation signal is attributed to the facts that reverse saturable absorption and large third order susceptibility of the dye molecules.
FT-IR Spectroscopy and SEM-EDX Studies on Nano Copper Doped Conducting Polymer
Authors: Shanmugapriya Chandran , Velraj Gothandapani
Published: October 2012

Polypyrrole (PPy) based metal composites have obtained considerable attention due to its fascinating properties such as appreciable electronic conductivity. This study is based on the system, pure polypyrrole (PPy) and nano copper doped polypyrrole (n-CuPPy) which were prepared by chemical oxidative polymerization method. The properties of PPy and n-CuPPy have been investigated by FT-IR,SEM-EDX and conductivity measurements. The FT-IR spectra showed the presence of all characteristics absorption peaks of PPy that is 881cm-1(=C-H out of plane vibration),1043cm-1(=C-H in plane vibration), 1182cm-1 (N-C strech vibration ) and 1552cm-1 (pyrrole ring vibration). The morphological structures and semi quantification of elements present in the pure and nano copper doped composite have been analysed using Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy. The conductivity measurements have been measured using two probe technique. We compare the conductivities of pure PPy with nanocomposite. The conductivity of n-CuPPy is 2x10-3 S/cm and PPy is 2.5x10-5 S/cm. The conductivity of n-CuPPy have been increased by two order when compared with PPy. The increase in conductivity in composite materials than PPy is due to the incorporation of nano copper particles into the PPy matrix.
Investigation on Rare Earth Doped Nonlinear Optical Potassium Hydrogen Phthalate (KHP) Single Crystals
Authors: Sudhahar S. , Kumar M. Krishna , Kumar R. Mohan
Published: October 2012

Rare earth doped potassium hydrogen phthalate (KHP) single crystals have been grown by slow evaporation technique. Single and powder X-ray diffraction analysis confirms the structural and crystallinity of grown crystals. The functional groups of pure and doped KAP crystals have been identified by FTIR spectral studies. UV-Vis studies explore the optical transmittance of the grown crystals in the entire visible region. Nonlinear optical property of the pure and doped KHP crystals was confirmed by Kurtz-Perry powder test.
Growth and Characterization of Zinc Doped L-Proline Cadmium Chloride Single Crystals
Authors: Vetrivel S. , Rajasekaran R.
Published: October 2012

Single Crystals of 20% of Zinc doped L- Proline Cadmium chloride [Zn(20M):LPCC] and 40% of Zinc doped L-Proline Cadmium chloride[Zn(40M):LPCC]were successfully grown from aqueous solution by slow evaporation method at room temperature. The grown crystals of [Zn(20M):LPCC] and [Zn(40M):LPCC] have dimensions 47x14x3.7 mm3 and 36x9.5x4.2 mm3 respectively. The single crystal XRD, powder XRD patterns were recorded and indexed for crystalline nature of grown materials. The presence of functional group has been confirmed by FTIR analysis. The optical transmission spectrum has been recorded in wavelength region 100nm to1000nm.The thermal properties were studied by TGA/DTA. The second harmonic generation (SHG) was carried out and it reveals the NLO property of the crystals. The electrical properties were studied by dielectric studies.
Effect of Electric Field on Nonlinear Optical Properties of Hydrazone Doped PMMA Films
Authors: Siji Narendran N.K. , Reshma K.R. , Sudheesh P. , Chandrasekharan K.
Published: October 2012

We report the effect of electric field on third order nonlinear optical properties of Hydrazone (Hz) doped Polymethyl methacrylate (PMMA) films. The films were prepared by solution casting method. Poling of films was done by corona discharge. Single beam Z-scan technique with 7ns Nd: YAG laser pulses at 532nm were employed for the measurements. Third order susceptibility of films was measured with an emphasis on the applied electric field. We also demonstrated the second harmonic generation in the corona poled films.
Coarsening Mechanism of Isothermal Heat Treatment for ADC14 Semi-Solid Alloy
Authors: Wang Zhen Yu , Ji Ze Sheng , Xu Hong Yu , Zhang Tie Lei
Published: October 2012

The strain-induced melt activation (SIMA) process is one form of the thixoforming for aluminum alloy. However, the non-uniform stress distribution restricts its application. In order to avoid this problem, a chip recycling strain-induced melt activation (CR-SIMA) process has been developed to prepare semi-solid billet. Microstructures of semi-solid ADC14 aluminum alloy billets heated to different temperatures and held for various times were investigated. The typical semi-solid microstructure with globular solid particles distributed in the liquid matrix is obtained in the temperature range of 560 and 565oC. The spheroidizing mechanism of ADC14 alloy prepared by the CR-SIMA process was studied. It was found that the severe deformation not only influences the solidification of spherical α-Al particles, but also affects the morphology of primary Si. The primary Si phases become tiny particles and distribute around the α-Al particles.
Experimental Investigation on 7075 Aluminium Response during Thixoextrusion
Authors: Neag Adriana , Favier Véronique , Pop Mariana , Bigot Régis
Published: October 2012

The deformation behavior of semi-solid aluminium alloy is strongly dependent on the microstructure. This paper illustrates several experimental research works concerning thixoextrusion of 7075 aluminium alloy which was carried out at “Arts et Métiers ParisTech” of Metz. The microstructure obtained by two reheating systems and flow behavior during thixoextrusion tests were investigated. To minimize the heat losses, a sample obtained from a direct extruded bar is inserted in a die for reheating in semisolid state and for thixoextrusion. Reheating the steel die and the aluminium billet placed into the die at the same time using an induction furnace provides rapidly a very homogeneous microstructure suitable for thixoforming. During the experimental re-heating process, the temperature was directly controlled using thermocouples for temperature measurements in the sample and also in the die. The experimental results on extrusion load and microstructure evolution of the component are reported.
Alloys for Semi-Solid Processing
Authors: Atkinson Helen V.
Published: October 2012

The main alloys which have been semi-solid processed commercially are based on aluminium (particularly the cast compositions) and magnesium. There is a strong drive to broaden the range of alloys to the wrought compositions for aluminium, more creep-resistant magnesium recipes and to higher temperature alloys such as those based on copper, steels, stellites and cast irons. This paper will summarise the issues with such development including the scientific and practical issues for alloy design and the thermodynamic prediction of alloys suitable for semi-solid processing. After an initial introduction to semi-solid processing routes, the most important alloy systems for semi-solid processing from a development point of view (aluminium, magnesium, steels and composites- including nanocomposites) will be discussed. The key issues of alloy design specifically for semi-solid processing will be drawn out through the text.
Property and Quality Optimization of Laser Welded Rheo-Cast F357 Aluminum Alloy
Authors: Theron Maritha , Burger Herman , Ivanchev Lilian , van Rooyen Corney
Published: October 2012

F357, a hypo-eutectic Al-7%Si-0.6%Mg alloy without beryllium, was processed with CSIR-Rheo technology to the Semi-Solid Metal (SSM) state and cast in plates by means of High Pressure Die Casting. The castings were either left in the as-cast (F) condition or subjected to T4 or T6 heat treatments prior to autogenous Nd:YAG laser welding. A welding operating window was established and within this window, the weld porosity and undercut were minimised. Butt welds complying with ISO 13919-2: 2001 could be produced by means of the optimum parameters of 3.8 kW laser power and a welding speed of 4 m/min with a twin spot laser beam configuration. The mechanical properties of age-hardenable Al-Si-Mg alloys are dependent on the rate at which the alloy is cooled after the solution heat treatment. The low heat input provided by the laser welding process resulted in high enough cooling rates to ensure that both the fusion zone and HAZ were in the T4 condition after welding. Tensile properties equivalent to the parent metal in T6 condition were obtained after subjecting welded T4 plates to conventional artificial ageing treatment.
Determination of Quantity and Localization of Liquid in the Semi-Solid State Using both 3D X-Ray Microtomography and 2D Techniques for Steel Thixoforming
Authors: Gu Guo Chao , Pesci Raphaël , Becker Eric , Langlois Laurent , Bigot Régis
Published: October 2012

The distribution of liquid at the semi solid state is one of the most important parameters for steel thixoforging. It has a great influence on the viscosity of the material, on the flows and finally on the final shape and mechanical properties of the thixoforged parts. Both ex situ and in situ 3D X-ray microtomography characterizations have been carried out to determine the quantity and localization of liquid at high temperature of M2 steel slugs. Microtomography was first performed ex situ at room temperature on samples heated and quenched from semi-solid state. The specimens were also scanned in situ directly at high temperature. The obtained results have been compared to 2D observations using EDS technique in SEM on heated and quenched specimens. They showed a good correlation making both approaches very efficient for the study of the liquid zones at the semi-solid state
Micro-Compression Test of Thixoformed Austenite
Authors: Mašek Bohuslav , Aišman David , Jirková Hana , Wurster Stefan
Published: October 2012

Thixoforming is an alternative forming method, by which intricate and complex-shaped products can be manufactured using a single production step. This technology allows a material’s microstructure to be altered profoundly. Typical microstructure of steels processed in this manner consists of quasi-polyhedral austenite grains embedded in a ledeburite-carbide network. This type of microstructure was produced by processing the experimental material in this study: the X210Cr12 steel. Since austenite is a metastable component depending on oversaturation with a number of elements, its thermal and mechanical stability needs to be known. This information is required for further modification and enhancment efforts. In previous experiments, the thermal stability was tested by thermal exposure. In the present work, the behaviour of austenite was explored under mechanical load at room temperature in a micro-compression test. A single block of austenitic material was used for making a test specimen with the dimensions of 2.4×2.2×4.9 µm. Its mechanical properties were measured and deformation stability was investigated using compressive deformation.
Microstructure of Thixoformable Hypoeutectic Cast Iron
Authors: Zoqui Eugênio José , Roca Angel Sanchez , Fals Hipólito Domingo Carvajal
Published: October 2012

The use of a specially designed hypoeutectic cast iron as a potential raw material for the thixoforming process is described in this paper. Thixoforming technology normally uses aluminum-silicon alloys such A356 and A357 as raw materials. Iron-based alloys are less common, despite the lower cost of the raw material. The paper describes the semi-solid behavior and corresponding final microstructure of a hypoeutectic gray cast iron after thixoforming tests. The Fe-2.6wt%C-1.5wt%Si alloy was prepared via conventional casting in sand molds. Samples were heated to the semi-solid state at 1160 and 1180oC and held at these temperatures for 0, 30, 90 and 120s, and then subjected to compression tests. Two-platen compression tests were carried out in an instrumented eccentric press in order to determine the semi-solid behavior. The holding time in the semi-solid range simulates the industrial heating process that is time-controlled rather than temperature-controlled. The semi-solid behavior indicated that the semi-solid cast iron behaves like aluminum-silicon alloys, presenting a stress of up to 24MPa under 80% strain and a corresponding apparent viscosity of up to 1.5*105 Pa.s at 1180oC. The final microstructure after compression testing was essential in determining the material’s morphological evolution. Tests revealed that heating up to the semi-solid range followed by thixoforming changes the material’s graphite morphology from type A to B (or E), but does not significantly affect the interdendritic arm spacing between graphite lamellae. The resulting structure is composed of fine graphite and pearlite.
Corrosion Behaviour of High Pressure Die-Cast and Semi-Solid Cast AZ91, AM60 and AM50 Alloys
Authors: Mariani Simone Umberto , da Forno Anna , Bestetti Massimiliano
Published: October 2012

A comparison of corrosion resistance of die-cast and semi-solid cast AZ91, AM60 and AM50 magnesium alloys was performed in different corrosive media by measurement of the open circuit potential, potentiodynamic scans and weight loss tests. Before testing, a heat treatment was carried out onto semi-solid cast alloys. Electrochemical measurements have shown that the semi-solid cast alloys have a different corrosion rate compared to the die-cast ones. The results could be correlated to the different microstructures of the samples produced by the different processes.
Microstructure and Mechanical Properties of Squeeze Cast Semi-Solid Materials
Authors: Guo Hong Min , Yang Xiang Jie , Zhang Shu Guo , Luo Lei
Published: October 2012

Several rheocasting processes have been developed or applied in the world. One of the new rheocasting processes is the limited angular oscillation (LAO), in which the molten metal is rapidly cooled and slightly mixed during initial stages of solidification. Squeeze casting (SQC) using semi-solid slurry produced by LAO (Rheo-SQC) has been developed. Microstructure and mechanical properties of squeeze cast semi-solid slurries have been investigated. Complete parts with little defects have been produced. The ultimate tensile strength and elongation of semi-solid cast samples are higher than those of the liquid cast samples. It can be concluded that the rheo-SQC is a feasible process.
A Boubaker Polynomials Expansion Scheme for Solving the Flow of Nonlinear Power-Law Fluid in Semi-Solid State
Authors: Wang Kai Kun , Fu Jin Long , Si Xin Hui
Published: October 2012

The problem of an uncompressible power-law fluid has long been the challenge in semi-solid forming area. In this paper, the flow of a power-law fluid film on an unsteady stretching surface is analyzed by the means of Boubaker Polynomials Expansion Scheme (BPES). Analytic solutions were given and compared with the numerical results for some real power-law index and the unsteadiness parameter in wide ranges. The good agreement between them showed BPES could be used effectively to solve the flow of nonlinear power-law fluid in semi-solid state.
Investigate on Flexible Thixo-Extrusion of Complex Part
Authors: Lv Xiao Lei , Wang Kai Kun , Zhou Lu
Published: October 2012

An inventive method of flexible thixo-extrusion technology was put forward, in which the stress status on flow front surface was controlled during thixo-forming. A complex part with different dimensions in three axis directions was designed. The velocity of sliding die was controlled by spring. This kind of die construction could make sure that the flow front of the slurry was always in compressive stress status. The velocity field, effective strain fields, effective stress fields were simulated and analyzed. The results showed that the thixo-extruded complex part was produced under compressive forming state, which forecast good mechanical properties in the practical experiment.
Study on Thixotropic Property of A356 Alloy in Semi-Solid State
Authors: Simlandi Sudip , Barman Nilkanta , Chattaopadhyay Himadri
Published: October 2012

In the present work, the thixotropic property of a semisolid aluminium alloy (A356) under deformation is investigated numerically where the Couette flow between two parallel plates is considered. The flow field is represented by momentum conservation equations where the non-Newtonian behavior of the semisolid material is represented by the Herschel-Bulkley model. The agglomeration and the de-agglomeration phenomena of the suspended particles under shear are represented using a time dependent structural parameter influenced by the rate of strain and shear stress. The simulation predicts the flow field, rate of strain and apparent viscosity of the semisolid materials under transient and steady state conditions. It is found that the apparent viscosity shows a transient nature during sudden change in the shear rate, and its value decreases with increasing shear rate and vice-versa. It is also found that the present prediction shows a good agreement with prior work.
Industrial Applications of Rheoforming Technology in China
Authors: Keung W.C. , Yang Xiang Jie , Shan Wei Wei
Published: October 2012

Rheological forming, a semi-solid metal forming process, is one of the manufacturing technologies for near net shape forming. The technology has attracted global academic research interests in recent years. This paper presents the current status of industrial applications of the semi-solid rheological forming technology in the China mainland. A variety of semi-solid slurry preparation techniques have been adopted including electromagnetic stirring and low superheat pouring. Dedicated semi-solid rheological forming equipment developed by the local manufacturers have been highlighted. This paper also makes an attempt to review the crucial factors for successful industrial application of the semi-solid metal forming process.