Mansi Sharma; Deepika Chaudhary; s. Sudhakar; Preetam Singh; K.M.K. Srivatsa; Sushil Kumar
Abstract
The structural investigation of the a-Si:H material, deposited at different pressures by PECVD process, has been carried out to analyze the signatures of diffused intermediate sort of crystalline phases within the amorphous silicon matrix. Raman characterization along with the Photoluminescence ...
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The structural investigation of the a-Si:H material, deposited at different pressures by PECVD process, has been carried out to analyze the signatures of diffused intermediate sort of crystalline phases within the amorphous silicon matrix. Raman characterization along with the Photoluminescence (PL) and spectroscopic ellipsometry studies were carried out to understand the microstructuree of these films. From Raman analysis the material was found to have indistinguishable crystalline phase, which can also be named as “intermediate amorphous phase” (a phase defined between amorphous and ultra nano-crystalline silicon) with crystalline volume fractions as 56 % and 62 % for 0.23 Torr and 0.53 Torr respectively. Here the contribution of ultra nano-crystallites results in higher crystalline fraction, which is not visibly revealed from the Raman spectra due to its sub nano-crystallite characteristics. For the film deposited at 0.53 Torr stable photo-conductance in conjunction with high photo-response under 10 hour light soaking has been observed, which is as expected due to high crystalline volume fraction. The presence of these phases might be the possible reason for the distinct device characteristics though having nearly the similar electrical properties (photo-response ~104). These studies will help to make improvement in the individual layer properties, other than the interface effect, in the fabrication of efficient p-i-n solar cells.
K. Srilatha; D. Bhagawan; V. Himabindu
Abstract
Hydrogen is an environmental friendly fuel, which has the potential to significantly used of fasil files; however several important challenges must defeat before it can be extensively used. Thermo catalytic decomposition of methane (TCD) is one of the most useful method, which will meet the future demand ...
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Hydrogen is an environmental friendly fuel, which has the potential to significantly used of fasil files; however several important challenges must defeat before it can be extensively used. Thermo catalytic decomposition of methane (TCD) is one of the most useful method, which will meet the future demand and hence an attractive route for COx free production of hydrogen which is essential in fuel cell. In the present study, we made an attempt on hydrogen production with Cu-Al2O3 and 5, 10, 15 & 20wt% of Ni modified Ni/Cu-Al2O3 catalysts. It is also observed that, the conversion order is Cu-Al2O3<5 wt% Ni/Cu-Al2O3 ~ 20 wt% Ni/Cu-Al2O3 <15 wt% Ni/Cu-Al2O3 < 10 wt% Ni/Cu-Al2O3 catalysts. It is observed that, while increasing the loadings of nickel in Ni/Cu-Al2O3 the efficiency of thermo catalytic decomposition of methane is also increasing. Among five catalysts prepared the 10wt% Ni/Cu-Al2O3 catalyst is showing good catalytic activity.SEM images of catalysts after thermo catalytic decomposition of methane shows the formation of carbon nanofibers. XRD patterns of the Cu-Al2O3 and 5,10,15 & 20wt%Ni/Cu-Al2O3 catalysts revealed, fairly crystalline peaks of which may responsible for the increase in the catalytic life and the formation of carbon nanofibers. The optimum hydrogen production of 70 volume % was observed with 10 wt% Ni/Cu-Al2O3 catalyst along with hydrogen carbon fibers were also found, which can be used as catalyst support. Copyright © 2016 VBRI Press.
Agnieszka Ślosarczyk; Paulina Jakubowska
Abstract
In presented article the research on sol-gel synthesis of silica aerogel from cheaper precursor water glass with ambient pressure drying was shown. In addition to strengthen the silica aerogel frame the as-received and oxidized carbon microfibers from coal-tar pitch were used. The presence of carbon ...
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In presented article the research on sol-gel synthesis of silica aerogel from cheaper precursor water glass with ambient pressure drying was shown. In addition to strengthen the silica aerogel frame the as-received and oxidized carbon microfibers from coal-tar pitch were used. The presence of carbon microfibers in silica aerogel does not influence the structural parameters, on the contrary, the carbon microfibers diminish the density and contraction during drying of silica aerogel nanocomposite. Modification of the silica aerogels in a mixture of TMCS/n-hexane in 70°C with concurrent modification of carbon microfibers results in obtaining a durable nanocomposite, up to the temperature of 600°C, characterized by high level of hydrophobicity, which is proved by tests on contact angle. Moreover, the analysis with EDS probe proved, in case of the nanocomposites with carbon microfiber, a lack of sodium, being a remnant of the silica gel synthesis from water glass, which implies a higher level of substrate reaction during the sol-gel synthesis, and results in obtaining better parameters of the silica aerogel. Copyright © 2018 VBRI Press.
R. Sri Siva; M. Shunmuga Priyan
Abstract
The effect of cryogenic treatment on the enhancement of tensile residual stress resistance in the SAE 52100 bearing steel was studied using X-Ray diffraction technique. The tensile residual stress behaviour is assessed by X-Ray diffractometer as per the ASTM standard E2860-12. Refinement of carbide particle ...
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The effect of cryogenic treatment on the enhancement of tensile residual stress resistance in the SAE 52100 bearing steel was studied using X-Ray diffraction technique. The tensile residual stress behaviour is assessed by X-Ray diffractometer as per the ASTM standard E2860-12. Refinement of carbide particle by deep cryogenic treatment (DCT) is often proposed as the improvement for the residual stress in the bearing steel. X-Ray diffractometer technique include the identification and quantitative analysis of crystalline chemical compounds (phase analysis and quantification, e.g. retained austenite determination), residual macro- and micro-stress analysis. It was found that the tensile residual stress was increased by +30Mpa due to deep cryogenic treatment when compared with that of conventional heat treatment (CHT). Moreover, the hardness of the DCT samples shows an improvement of 15% over the CHT samples.
E.M. Oks; A.V. Tyunkov; Yu.G. Yushkov; D.B. Zolotukhin
Abstract
This paper presents a novel technique for producing alumina ceramic coatings based on the evaporation of an aluminum oxide target by an electron beam in the middle vacuum range (5-30 Pa). The evaporation of ceramics by the electron beam enables to attain a coating deposition rate of up to 0.3 µm/min, ...
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This paper presents a novel technique for producing alumina ceramic coatings based on the evaporation of an aluminum oxide target by an electron beam in the middle vacuum range (5-30 Pa). The evaporation of ceramics by the electron beam enables to attain a coating deposition rate of up to 0.3 µm/min, and thus consider this as a practical alternative to existing methods. A special attention is devoted to the study of the surfaces of obtained coatings. The X-ray fluorescence analysis of the deposited coating showed the presence in the coating of all the elements that contained in the ceramic target being evaporated. The coating has a substantially homogeneous surface without any prominent pores.
Suranjan Sikdar; Sutanuka Pattanayek; Tanmay K Ghorai
Abstract
The Bi2MoZnO7 nanocomposites have been successfully synthesized via co-precipitation and solid state method and followed by a low temperature calcinations treatment process. We find that such a Bi2MoZnO7 nanocomposite exihibits higher photoctatalytic activity and stability than Bi2MoO6, Bi2O3 and ZnO ...
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The Bi2MoZnO7 nanocomposites have been successfully synthesized via co-precipitation and solid state method and followed by a low temperature calcinations treatment process. We find that such a Bi2MoZnO7 nanocomposite exihibits higher photoctatalytic activity and stability than Bi2MoO6, Bi2O3 and ZnO towards the aqueous phase degradation of Rhodamine B (RhB) under visible light (420 nm < λ). The presence of Bi3+/Mo6+/Zn2+ ions in Bi2MoZnO7 and formation of defects in the lattice is believed to play an essential role in affecting the photoreactivity. The different types of active species scavengers are also play the photocatalytic process. The synthesized Bi2MoZnO7 nanocomposites were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), SEM, TEM, EDAX and IR techniques. The crystallite sizes, particle and grain sizes are 12±2, 5±1 and 100±5 nm, respectively. The rate of degradation of Rhodamine B by BMZ in aqueous phase is 7 times (40.70×10-3min-1) faster in comparison to pure Bi2O3/ZnO. Copyright © 2017 VBRI Press.
Dinesh Ramesh; Giri Prasad.M.J; Abhishek Raaj.A.S; Jerome Santharaj.N; Rishi Kumar.R; Santhip. J; Devashankar. S
Abstract
Engine oil is primarily used to carry away the excess heat from engine and to provide lubrication to moving parts of the engine, thereby reducing friction and wear between the rubbing surfaces. However with time net heat stored in the bulk of the engine oil becomes greater than its thermal conductivity ...
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Engine oil is primarily used to carry away the excess heat from engine and to provide lubrication to moving parts of the engine, thereby reducing friction and wear between the rubbing surfaces. However with time net heat stored in the bulk of the engine oil becomes greater than its thermal conductivity causing a drastic reduction in its viscosity leading to formation of oil sludges inside the engine. Previous studies prove that the nano engine oil prepared by dispersing nanoparticles into engine oil provides enhanced operational characteristics when compared to plain engine oil, but are accompanied by the high cost of preparation and low stability of the nano engine oil[1]. In the present study a nano base oil which is a dispersion of MWCNTs and ZnO nanoparticles of ratio 1:4 in mineral oil was prepared by the two step preparation process. Tribological properties such as wear resistance, friction co-efficient and thermophysical properties such as thermal conductivity, viscosity, flash point of the nano base oil were evaluated and were compared with SAE 20W40 engine oil. The results obtained reveal that nano base oil possess better tribological and thermophysical properties when compared to engine oil, which will eventually improve the lifetime of the engine components. Copyright © 2018 VBRI Press.
A. Kaviarasi; M.V.L. Kumari; A.R. Prabakaran; A. Anandavadivel
Abstract
Intercalated composite films of Ethylene Vinyl Acetate (EVA) with sodium silicate (SS) are prepared using solvent casting technique. The films are prepared by varying the vinyl acetate percentage in EVA and suitable quantities of sodium silicate in wt/wt concentration are mixed in EVA solution with high ...
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Intercalated composite films of Ethylene Vinyl Acetate (EVA) with sodium silicate (SS) are prepared using solvent casting technique. The films are prepared by varying the vinyl acetate percentage in EVA and suitable quantities of sodium silicate in wt/wt concentration are mixed in EVA solution with high speed stirring for homogenous dispersion. The functional groups present in both EVA and EVA/SS films are confirmed through FTIR spectral analysis. Stress-Strain curves are obtained for both EVA and EVA/SS films in order to determine the improvement in various tensile parameters. An increase in the thermal stability of the developed composite was recorded by thermo gravimetric analysis (TGA). Copyright © VBRI Press.
Shanthi Jayachandran; Mohan Raman; Palanisamy Ponnusamy
Abstract
Wire Electrical Discharge Machining is one of the most effective Non-Conventional Machining method available to machine intricate shapes which are very difficult to machine with conventional machining methods, on electrically conductive materials havingvarying hardness. In this research work, an attempt ...
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Wire Electrical Discharge Machining is one of the most effective Non-Conventional Machining method available to machine intricate shapes which are very difficult to machine with conventional machining methods, on electrically conductive materials havingvarying hardness. In this research work, an attempt hasbeen made to study the effect of process parameters of WEDM on the Surface roughness. Input process parameters considered in this work are Pulse on time (TON), Pulse off time(TOFF), Wire Feed (WF), Wire Tension(WT) and theSurface Roughness as response. Al 7075 Aluminium alloywas taken as work material and Brass coated copper wire as electrode to machine and the values of roughness obtained by varying the input process parameters were analysed using Taguchi method (L 27 orthogonal array). The measured values have been used to develop the mathematical modeland the accuracy of the model wastested using Analysis of Variance (ANOVA) technique. Based on the predicted values the interaction graphs, were drawn betweentheSurface roughnessandthe processparameterstaken for this study. It was construedthatthepulse-on time has the highest impact on the Surface roughness followed by the Wire feed, Wire tension and the Pulse-off time. The surface roughnessgot increasedwith increase in wire feed. Finally optimum parameters have been arrived to achieve better surface roughness. WEDMed surface was also examined by using scanning electron microscope (SEM) and evinced that the physical behaviour of these process parameters on Surface roughness.Copyright © VBRI Press.
Ranu Pal; Sandeep Kumar Singh; M.J. Akhtar; Kamal K. Kar
Abstract
Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental ...
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Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental knowledge of these properties is essential for processing of materials using microwaves. In this study, first the dielectric evolution of silicon carbide (SiC) infused epoxy nanocomposites prepared at room temperature with 0-0.3 wt% content of SiC was measured. Secondly, the dielectric properties of the prepared nanocomposites after heating for 10 min in microwaves at a power of 500 W were investigated in order to see the effect of microwave curing. The dielectric properties of all the samples were measured at the microwave frequency of 2.45 GHz using the advanced cavity perturbation method attached to a vector Network Analyzer (VNA). The results indicate that the dielectric properties of the resultant nanocomposites increase with the increase in SiC content as compared to the neat epoxy sample. However, the dielectric properties were found to be decrease after microwave curing signaling the maximum possible extent of curing. This indicates that reinforcement of SiC nanoparticles in epoxy makes them ideal candidates for efficient microwave curing of nanocomposites. Lastly, the determination of thermal properties also confirms the maximum possible extent of curing of epoxy using SiC as nanofillers. Copyright © 2018 VBRI Press.
Debasree Burman; Ravindra Kumar Jha; Sumita Santra; Prasanta Kumar Guha
Abstract
In our paper, few layered MoS2 nanoflakes were exfoliated from the bulk powder in mixed solvent using a simple sonication assisted liquid exfoliation technique at room temperature. The successful exfoliation of the nanoflakes was characterized using various characterization tools like Scanning Electron ...
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In our paper, few layered MoS2 nanoflakes were exfoliated from the bulk powder in mixed solvent using a simple sonication assisted liquid exfoliation technique at room temperature. The successful exfoliation of the nanoflakes was characterized using various characterization tools like Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Atomic Force Microscopy (AFM). The humidity sensor was fabricated by drop-casting MoS2 nanoflakes on Pt-based Interdigitated Electrodes (IDEs). The sensing was carried out in an in-house gas test setup interfaced with a Semiconductor Parameter Analyzer (SPA) to record the measurements. The response of the sensor was studied by passing different levels of humidity through the gas chamber. The response was found to increase with increase in humidity level and was better than few recently reported results. The maximum response was found to be ~16 times at 75% RH. Since water is an electron donor and MoS2 is inherently n-type semiconductor, the conductivity of the MoS2 sensing layer increased in presence of humidity. The large surface to volume ratio and presence of inherent defects facilitated the adsorption and desorption of a large number of H2O molecules. The response time and recovery time of the sensor was 65 seconds and 72 seconds respectively. Thus we conclude that our MoS2 based humidity sensor with a maximum response of 16 times (75% RH) can act as a low power, highly sensitive and fast humidity sensor in various applications like indoor air quality monitoring, agriculture, semiconductor industry etc.
Eagambaram Murugan; Chennakesavapuram R Akshata; Annie Stephy
Abstract
Capecitabine (CPT) is an oral antineoplastic prodrug of 5-Flurorouracil (5-FU), administered for the treatment of metastatic breast and colorectal cancers. Detection of trace quantity of Capecitabine in pharmaceutical drug dosages is very crucial and essential owing to its life threating toxic adverse ...
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Capecitabine (CPT) is an oral antineoplastic prodrug of 5-Flurorouracil (5-FU), administered for the treatment of metastatic breast and colorectal cancers. Detection of trace quantity of Capecitabine in pharmaceutical drug dosages is very crucial and essential owing to its life threating toxic adverse effects. In this study, an effective conducting nanohybrid namely, MWCNT-PAMAM (G3)-AuNps was developed and characterized by Raman, FT-IR, SEM and HR-TEM techniques. The developed conducting nanohybrid was used for fabrication of effective and stable active electrode viz., GCE-MWCNT-PAMAM (G3)-AuNps which in turn demonstrated for effective sensing of trace quantity of Capecitabine i.e., at a concentration of 5 x 10-12 M under lower potentials. The reduction of Capecitabine was investigated through cyclic voltammetry in the presence of H2SO4 (pH 1.54) as supporting electrolyte. The presence of Capecitabine exhibited an irreversible reductive peak potential at ~0.835 V which was observed from mixed diffusion-adsorption controlled processes. The mechanism for electrochemical-chemical reduction, trace and rapid determination of Capecitabine are reported. This newly developed electrode has a potential to sense/ detect the Capecitabine at the concentration of 5 x 10-12 M under lower potentials. Further, it is expected that there is a strong scope for quality control in pharmaceutical formulates. Copyright © 2017 VBRI Press.
Eagambaram Murugan; Venkatesan Yogaraj
Abstract
Quaternary ammonium poly(amidoamine) (PAMAM) dendrimer stabilized gold nanoparticles (QPAMAM-AuNPs) were prepared and used for fabrication of new GC-QPAMAM-AuNPs electrode and this in turn was investigated for sensing of trace quantity of H2O2. Further, the QPAMAM-AuNPs were inspected for catalysis of ...
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Quaternary ammonium poly(amidoamine) (PAMAM) dendrimer stabilized gold nanoparticles (QPAMAM-AuNPs) were prepared and used for fabrication of new GC-QPAMAM-AuNPs electrode and this in turn was investigated for sensing of trace quantity of H2O2. Further, the QPAMAM-AuNPs were inspected for catalysis of nitrobenzene. Initially, amine-terminated PAMAM dendrimer was neutralised by acetylation followed by quaternization reactions. This quaternized product was used as a template for stabilization of gold nanoparticles by conducting the reactions at room temperature and thus produced quaternized dendrimer stabilised gold nanoparticles labelled as QPAMAM-AuNPs. The synthesized QPAMAM-AuNPs were characterized by UV-Vis, FTIR, 1H NMR, MALDI-TOF and TEM analyses. This QPAMAM-AuNPs was coated on newly produced glassy carbon modified electrode without any binding agent, particularly any enzyme to produced GC-QPAMAM-AuNPs electrode. This newly fabricated electrode in turn were employed for detection and sensing of trace quantity of H2O2 and it is observed that the electrode has an ability to detect the H2O2 ranging from [100 µM] to [5 mM] in neutral pH. Similarly, it is also proved that QPAMAM-AuNPs has effectively reduced the nitrobenzene and the observed pseudo-first order rate constant was 25.25 ×10-3s-1. It is established that the stabilized nanoparticles are water-soluble and stable for three months. Copyright © 2017 VBRI Press.
Sultan A. Al-horaibi; S.T. Gaikwad; Anjali S . Rajbhoj
Abstract
The requirement for energy is ever increasing in the past few years due to the need for the innovation of clean energy and eco-friendly technologies. Symmetric and asymmetric SQ-dyes have received increasing attention and great potential for use as SQ-sensitizers for application in dye sensitized solar ...
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The requirement for energy is ever increasing in the past few years due to the need for the innovation of clean energy and eco-friendly technologies. Symmetric and asymmetric SQ-dyes have received increasing attention and great potential for use as SQ-sensitizers for application in dye sensitized solar cells (DSSC).This review article gives a synopsis of the advancements on SQ-sensitizers in the domain of DSSC and the chance used to enhance their overall energy conversion efficiency. Specifically, the primary factors in charge of the low values of open-circuit voltage (Voc) short-circuit photocurrent (Jsc) and fill factor (FF) are debated in detail. Future orientations in research and expanded absorptions of near-infrared region (NIR) by development organic substances and their applications are suggested from a personal point of view. Copyright © 2018 VBRI Press.
Kartick Prasad Dey; Sumit Mishra
Abstract
In this article, we have reported the synthesis of Polyacrylamide grafted Barley (Ba-g-PAM) by free radical copolymerization technique. Ceric ammonium nitrate (CAN) was used as a free radical initiator for this synthesis process. Various grades of Ba-g-PAM were synthesized by varying the CAN and AM concentration. ...
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In this article, we have reported the synthesis of Polyacrylamide grafted Barley (Ba-g-PAM) by free radical copolymerization technique. Ceric ammonium nitrate (CAN) was used as a free radical initiator for this synthesis process. Various grades of Ba-g-PAM were synthesized by varying the CAN and AM concentration. The swelling properties of these different grades of Ba-g-PAM were performed in different pH media like 1.2, 6.8& 7.4 at 250C and 370C. All grades showed better swelling properties at 370C than 250C. The matrix tablets of different grades of grafted materials were prepared by following the standard protocol using 5-flurouracil as a model drug. The swelling and erosion property of each matrix tablet was performed at 370C in different pH media like 1.2, 6.8& 7.4. The percentage of drug released from different matrix tablets was determined in different pH media like 1.2, 6.8& 7.4 (similar to GI tract). The drug release kinetics was also determined with the help of percentage drug release results. The matrix tablet of best grade i.e. Ba-g-PAM5 follows non-fickian kinetics, so, the diffusion rate of drug from matrix tablet and the relaxation rate of the polymer chains in the matrix tablets are comparable. The acute oral toxicity test was performed on the basis of Organization of Economic Co-operation and Development (OECD) guidelines, showing non-toxic behavior. The above results support that the controlled release of5-flurouracil in the colonic region has been successfully carried out. This developed material may be of help in the colon cancer treatment. Copyright © 2017 VBRI Press
Sarajit Biswas
Abstract
First principles electronic structure calculations implemented in the density functional theory have been employed to investigate the electronic and magnetic properties of VO2 in the high temperature rutile structure with tetragonal P42/mnm symmetry. The system is a nonmagnetic metal in the absence of ...
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First principles electronic structure calculations implemented in the density functional theory have been employed to investigate the electronic and magnetic properties of VO2 in the high temperature rutile structure with tetragonal P42/mnm symmetry. The system is a nonmagnetic metal in the absence of Hubbard- type Coulomb interaction U. It is revealed in this study that the three V-t2g states are degenerate due to partial electron filling which is responsible for orbital fluctuations between them. Due to these orbital fluctuations and sharing of single 3d electron by V-t2g states, no band gap opens in the close vicinity of Fermi level. Nevertheless, upon the application of U = 4 eV, the system encounters metal to half-metal transition without any structural phase transitions exhibiting ferromagnetic behaviour. In spin up channel, dyz and dxz states remain degenerate while dx2- y2 state is more occupied but are strongly hybridized with O-2p orbitals resulting ferromagnetism. In spin down channel, Fermi level is suppressed below the V-t2g bands while V- 4s state is shifted above the Fermi level causing opening of a band gap near the Fermi level. Copyright © 2018 VBRI Press.
Kumar Biplab; Dibakar Rakshit
Abstract
Present study deals with estimation of thermal comfort of residential buildings for different scenarios. The three scenarios which are analysed for the present study are construction using brick wall and concrete roof, construction by utilization of insulation over walls and roof and construction by ...
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Present study deals with estimation of thermal comfort of residential buildings for different scenarios. The three scenarios which are analysed for the present study are construction using brick wall and concrete roof, construction by utilization of insulation over walls and roof and construction by utilization of Phase Change Materials (PCM) over walls and roof.A building is simulated in EnergyPlus using conduction finite difference algorithm. The PCM is microencapsulated in plaster boards thereby restricting any chemical reactions with the building material. The assessment is carried out by calculating the hourly average room dry bulb temperature and average room relative humidity. This is then compared with the thermal comfort conditions provided in National Building Code of India 2005 and a percentage of hours within comfort range is worked out. The assessment is carried out between the months of March and October for three cities i.e. Bhubaneshwar, Jodhpur and New Delhi, all under different climatic conditions. The results indicate that PCM is performing comparatively better than insulation in improving the indoor conditions and that its performance can be greatly enhanced if the operating temperature is increased from 27°C to at least 30°C. Combined with the strategy of night ventilation and enhanced heat capacity storage, PCM could greatly enhance the thermal comfort levels. Copyright © 2017 VBRI Press.
Mykhaylo Romanyuk; Martina Avalos; Edgardo R. Benavidez; Elena Brandaleze
Abstract
The application of IF steels in the automotive industry has increased significantly due to their excellent deep drawability. The chemical composition, the microstructure, the precipitation phenomena and texture of the material determine the mechanical properties. This paper proposes, a more profound ...
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The application of IF steels in the automotive industry has increased significantly due to their excellent deep drawability. The chemical composition, the microstructure, the precipitation phenomena and texture of the material determine the mechanical properties. This paper proposes, a more profound study of some aspects related to the application of high plastic deformation, as well as its relation with the formation of fine grain structures, texture, precipitates and grain boundaries interaction. The structure of an IF steel plate with ultra-low carbon was characterized using optical microscopy and scanning electron microscopy (SEM). A ferritic structure with very fine and recrystallized grains containing high number of triple point was observed. The precipitation kinetic of the steel was simulated applying Fact Sage 7.1. The main precipitates predicted are: TiN and TiS, these types of second phases improve the drawability behaviour. The formability aptitude of the sheet was evaluated by different mechanical tests: Hole Expansion, Erichsen and n-r determination. Finally, yield strength, tensile strength, percentage elongation and average r-value results, are correlated with the structural information. A strong (111) <110> recrystallization texture confirms the high formability of the IF steel sheet. Copyright © 2018 VBRI Press.
M.S. Charoo; M. F. Wani; M. Hanief; Aman Chetani; M. A. Rather
Abstract
Abrasive wear of steel-aluminium tribo-pair is one of the major problems in engineering applications. In this research study, our main objective is to find out the tribological behaviour of shaft material, usually made of hardened EN8 and EN24 steel under lubricated condition against Aluminium alloy ...
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Abrasive wear of steel-aluminium tribo-pair is one of the major problems in engineering applications. In this research study, our main objective is to find out the tribological behaviour of shaft material, usually made of hardened EN8 and EN24 steel under lubricated condition against Aluminium alloy 6061. A conventional lubricant SAE 20W50 has been used, as it is the most common lubricating oil used in IC engines. Tribological tests were conducted on reciprocating friction test rig using pin-on-disc configuration under various operating parameters such as speed, load and temperature. The effect of these parameters on friction and wear was studied. It was observed in this study that with increase in load and speed, the coefficient of friction decreased while it increased with increase in temperature. However, comparison of results revealed that with the increase in load, EN24 alloy is suitable than the EN8 steel with coefficient of friction as deciding factor. The specific wear coefficient and wear volume increased with increase in all of these parameters and it was observed that under varying speed the tribo-pair consisting of EN24 steel is more suitable in comparison to EN8 steel from the wear point of view.
Arul Murugesan; Robert M Gengan
Abstract
A simple and efficient procedure for the preparation of boron nitride bound N-propyl triethylenetetramine sulfonic acid (BN-BPTETSA) by the reaction of boron nitride bound N-propyl triethylenetetramine (3-TETANP BN) with chlorosulfonic acid in chloroform is described. The boron nitride (BN) ...
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A simple and efficient procedure for the preparation of boron nitride bound N-propyl triethylenetetramine sulfonic acid (BN-BPTETSA) by the reaction of boron nitride bound N-propyl triethylenetetramine (3-TETANP BN) with chlorosulfonic acid in chloroform is described. The boron nitride (BN) nanomaterial was prepared by first activating BN with nitric acid under reflux for 24h. Thereafter trimethoxy -3-mercaptopropylchloride was added, refluxed for 24 h then an excess of triethylenetetramine was added in anhydrous xylene and the system was refluxed. After filtration and washing of the filter cake with xylene, chlorosulfonic acid was added drop-wise at 0 °C over a period of 3 h. Further filtration yielded a solid cake which was washed with ethanol and air died. The morphological properties of catalyst was characterized by FT-IR, XRD, TEM, SEM, BET and Raman spectroscopy techniques. The preparation of the catalyst is safe and demonstrates high catalytic activity for the synthesis of piperazinyl quinolinyl carbaldehyde derivatives. Furthermore, a small amount of catalyst was used, demonstrated good reusability and may have potential for industrial applications in the future. Copyright © 2018 VBRI Press.
Mukesh Kumar; Neelam Kumari; Vinod Karar; Amit L Sharma
Abstract
HfO2 thin films have gained much significance in recent years as a promising dielectric material for semiconductor electronics added to their wide applications in the field of optical filters as a high index material. The resistance of HfO2 films to impurity diffusion and intermixing at the interface ...
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HfO2 thin films have gained much significance in recent years as a promising dielectric material for semiconductor electronics added to their wide applications in the field of optical filters as a high index material. The resistance of HfO2 films to impurity diffusion and intermixing at the interface as well as higher environmental stability have made these films one of the most extensively studied upon materials in laser optics, optical coatings and semiconductor domain. In the present study, Hafnium Oxide film was deposited on glass substrate using reactive oxygenated E-Beam deposition technique with in-situ quartz crystal thickness monitoring to control the film thickness and rate of evaporation. The coated substrate was optically characterized using spectrophotometer and Variable Angle Spectroscopic Ellipsometry (VASE) to determine its transmission spectra as well as optical constants. The coated sample was put under thermal stress testing in a test chamber with temperature variation from -40° to + 65° C in a cyclic manner for 7 cycles with a rate of temperature change of 5° C/minute. The coated sample was again optically characterized to investigate the effect of thermal cycling on its optical performance and physical parameters. Copyright © 2017 VBRI Press.
Raviraj M. Kulkarni; Ramesh S. Malladi; Manjunath S. Hanagadakar
Abstract
Photocatalytic degradation of textile dye derivative Methyl Orange (M.O) has been studied in aqueous medium using 2% copper doped zinc oxide (2% Cu-ZnO) nanoparticles under UV irradiation. Simple inexpensive chemical precipitation method was used for synthesis of pure and copper doped zinc oxide nanoparticles. ...
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Photocatalytic degradation of textile dye derivative Methyl Orange (M.O) has been studied in aqueous medium using 2% copper doped zinc oxide (2% Cu-ZnO) nanoparticles under UV irradiation. Simple inexpensive chemical precipitation method was used for synthesis of pure and copper doped zinc oxide nanoparticles. The prepared nanoparticles pure and copper doped zinc oxide was characterized by X-ray Diffraction Technique (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis. The prepared nanoparticles were hexagonal wurzite structure. Photocatalytic efficiency of 2% Cu-ZnO were evaluated by studying mineralization of methyl orange (M.O.) as a model compound. The M.O. kinetics degradation was investigated under different parameters such as pH of the medium, catalyst dosage, M.O concentration, intensity of light etc. In addition reusability aspects of nanoparticles where also studied, which reveals that reused nanoparticles exhibited same results as that of virgin particles. Copyright © 2018 VBRI Press.
B. Sreenivasulu; S Venkatramana Reddy; P. Venkateswara Reddy
Abstract
Pure and (Mn, Ni) co-doped ZnS nano particles are synthesized by co-precipitation method using Poly Vinyl Pyrrolidone (PVP) as stabilizer. Powder XRD results exhibit cubic blended structure for all samples. The average crystallite sizes observed to be between around 2-3 nm. Uneven changes of crystal ...
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Pure and (Mn, Ni) co-doped ZnS nano particles are synthesized by co-precipitation method using Poly Vinyl Pyrrolidone (PVP) as stabilizer. Powder XRD results exhibit cubic blended structure for all samples. The average crystallite sizes observed to be between around 2-3 nm. Uneven changes of crystal structure of concerned nanoparticles are confirmed by the Transmission Electron Microscopy (TEM) studies. The crystalline sizes obtained from TEM (3-5 nm) agree well those of XRD data. The SEM micro graphs of (Mn, Ni) co-doped nanoparticles result in agglomeration with spherical shape. The EDAX Spectra reveal that in the chemical composition of the prepared samples, the co-doped elements are incorporated into ZnS lattice. Photoluminescence (PL) has been studied at 306 nm wavelength. Pure sample exhibits sharp peaks at 438 nm, 450 nm and 466 nm. The (Mn, Ni) co-doped powders exhibit slightly less intense peaks. The magnetic measurements reveal that the co-doped nanoparticles exhibit Room Temperature Ferromagnetism (RTFM). Copyright © 2018 VBRI Press.
Bhawana Joshi; Santanu Ghosh; Pankaj Srivastava
Abstract
In the present work, ZnO thin films deposited by pulsed laser deposition (PLD) technique have been characterized structurally and optically after post-deposition annealing. As-deposited thin films were annealed in the ambient atmosphere for different annealing temperatures of 2000C, 4000C, 6000C and ...
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In the present work, ZnO thin films deposited by pulsed laser deposition (PLD) technique have been characterized structurally and optically after post-deposition annealing. As-deposited thin films were annealed in the ambient atmosphere for different annealing temperatures of 2000C, 4000C, 6000C and 8000C. X-ray diffraction (XRD) technique was used for structure analysis and elucidated that both as-deposited and annealed films were of good structural quality and highly oriented towards c-axis. UV-Vis spectrophotometer was used to study the transmittance and optical band gap of as-deposited and annealed films. Photoluminescence (PL) technique was used to investigate the photoluminescent properties of all the films. It was found that ZnO thin films were highly transparent in nature and showed two emissions in PL spectra. One was attributed to near band edge (NBE) emission and the other was the broad deep-level (DL) emission. There was a significant change in the photoluminescent properties of the films and it was observed that the intensity of the DL emission increased significantly with the increase in the annealing temperature. The change in DL emission is attributed to the change in defect states inside the band gap of the annealed films. From the present work, it is inferred that the properties of the ZnO films can be tuned by post-deposition annealing for various applications such as optical and optoelectronic devices. Copyright © 2017 VBRI Press.
Pradosh K. Sahoo; G. Mangamma; M. Kamruddin; S. Dash; Ashok K. Tyagi
Abstract
In the present work ZnO dendritic nanostructures (NS) were synthesized by sol-gel and spin coating methods over silicon (100) substrate. The phase purity was confirmed by XRD. Grain size was found to be less than 10 nm. The vibrational modes of the nano ZnO wurtzite structure were observed by laser Raman ...
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In the present work ZnO dendritic nanostructures (NS) were synthesized by sol-gel and spin coating methods over silicon (100) substrate. The phase purity was confirmed by XRD. Grain size was found to be less than 10 nm. The vibrational modes of the nano ZnO wurtzite structure were observed by laser Raman spectroscopy. Raman spectra revealed asymmetrically broadened red shift of E2 (high) optical phonon mode which accrues from contribution of Non-Brillouin Zone (NBZ) phonons. The shift in the peak is attributed to the quantum mechanical confinement of phonon due to their nano grains as inferred from XRD and morphological studies by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). SEM and AFM images revealed the leaf like dendrite structures having several branches. Possible growth mechanism has been discussed in line with the synthesis. Box counting method was implemented to determine the fractal dimension (D) and the value of D is found to be ~1.6±0.1. This work will be useful in designing novel optoelectronic devices and sensors from ZnO nanostructures (NS) exhibiting complex morphology. Copyright © 2017 VBRI Press.
