Mahlatse F. Manamela; Thuto E. Mosuang; Bonex W. Mwakikunga
Abstract
The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak ...
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The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak was observed in the diffraction pattern of the In doped ZnO nanopowders. Doping the ZnO nanoparticles with Co and In did not significantly affect the lattice parameters, even though the average grain sizes were found to be reduced. The morphology of the samples revealed by the scanning electron microscopy (SEM) images appear to be more spherical. The excitation wavelength of 350 nm was used in the photoluminescence (PL) study where various defects related emissions were observed for the doped and undoped ZnO nanoparticles. The energy band gap of the prepared samples was calculated from the ultraviolet-visible spectroscopy (UV-Vis) data. It was found that the doped ZnO nanoparticles had smaller energy band gap compared to the undoped ZnO nanoparticles. The Raman experiment were performed at the excitation wavelength of 514.532 nm and E2 (high) mode had the most intense peak. Copyright © 2018 VBRI Press.
Panmei Gaijon; S. K. Shukla; Monika Datta
Abstract
Presently, polymer-clay composites (PCC) have shown promising advancements in different properties of polymers due to presence of layered silicate structure and also extend its multi fold advanced applications. In the present work, vermiculite (VT) was organically modified by cetylpyridinium chloride ...
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Presently, polymer-clay composites (PCC) have shown promising advancements in different properties of polymers due to presence of layered silicate structure and also extend its multi fold advanced applications. In the present work, vermiculite (VT) was organically modified by cetylpyridinium chloride (CPC). Thus obtained organo vermiculite (OVT) was used to prepare its composite film with polystyrene (PS-OVMT) with varying amounts of OVT by the solution blending and casting method on a glass substrate. The prepared films were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), infrared (FT-IR) spectroscopy and thermal analytical (TG-DTA) techniques. X-ray diffraction pattern of the composite shows peaks of VT and PS along with decrease in the intensity of the PS peaks present between 2Ө = 12.5˚ to 24.5˚. Decreases in the intensity of peaks suggest dispersion of clay within the polymer matrix and lowering of crystallinity. The dispersion of clay and interaction with PS is also evident from the FTIR and microscopic data. Further, hardness test (shore-D), TG-DTA and flammability(UL-94) results of the composite indicate the improvement in hardness, thermal stability and inhibition in burning behaviour of the PS due to the presence of OVT in the PS matrix. Copyright © 2017 VBRI Press.
Nandeibam Nilima; Mamata Maisnam; Sumitra Phanjoubam
Abstract
Li-Ni-Co ferrite/SiO2 composites with representative formula Li0.41Ni0.1Co0.08Fe2.41O4+ xSiO2 (i.e., x = 0wt. %, 5wt. %,10wt. % and 20wt. %) were prepared by sol-gel method. The prepared composites were pre-sintered at 600ºC for 2 hrs and then finally sintered at 1000ºC for 6 hrs. X-ray diffraction ...
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Li-Ni-Co ferrite/SiO2 composites with representative formula Li0.41Ni0.1Co0.08Fe2.41O4+ xSiO2 (i.e., x = 0wt. %, 5wt. %,10wt. % and 20wt. %) were prepared by sol-gel method. The prepared composites were pre-sintered at 600ºC for 2 hrs and then finally sintered at 1000ºC for 6 hrs. X-ray diffraction studies showed diffraction peaks indicating single phase with spinel structure. However, peaks of SiO2 were found in composites of higher (x). The microstructure of the samples was studied by using Scanning Electron Microscopy. The crystallite size and average grain size were found to decrease with increase of SiO2 content. The room temperature frequency variation of dielectric constant and dielectric loss was measured from 100Hz-1MHz and they showed a dispersive behavior. The variation has been explained by Verwey mechanism of electron hopping and Koop’s two-layer model. The addition of SiO2 plays significant role in influencing the various structural, microstructural and electrical properties. Uniform and refined microstructures are observed with the addition of SiO2 and this reduces the value of dielectric constant and loss significantly, which is desirable for high frequency applications. The results obtained and mechanisms involved are discussed. Copyright © 2017 VBRI Press.
Himanshu Bisaria; Pragya Shandilya
Abstract
Ni-rich NiTi shape memory alloys (SMAs) are gaining more prominence compared to near equiatomic NiTi SMAs due to their excellent superelasticity and shape memory properties. The low density and high work output compared to steels make them an excellent choice for automotive and aerospace industries. ...
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Ni-rich NiTi shape memory alloys (SMAs) are gaining more prominence compared to near equiatomic NiTi SMAs due to their excellent superelasticity and shape memory properties. The low density and high work output compared to steels make them an excellent choice for automotive and aerospace industries. The study explores the effect of machining parameters, namely, pulse off time, pulse on time, spark gap voltage, wire tension and wire feed rate on material removal rate (MRR), surface roughness (Ra), and surface morphology of Ni-rich NiTi SMA. The experimental results reveal that MRR & Ra increase with the increase in pulse on time while decrease with the increase in pulse off time and spark gap voltage. Wire feed rate and wire tension have negligible influence on MRR and SR. Surface defects, namely, recast layer, micro-cracks & voids were examined through scanning electron microscope (SEM). Energy dispersive X-ray (EDS) and X-ray diffraction (XRD) analysis results reveal the material transfer from wire electrode and the dielectric fluid on the machined surface. Copyright © 2018 VBRI Press.
Nupur Jauhari; Gajula MNV Prasad; Neelam Sharma; Navneeta Bharadvaja
Abstract
The purpose of research: Colorectal cancer is third most prevalent cancer in developed countries with increasing cases in developing countries. Studies show that the chronic intestinal inflammation is associated with increased risk of developing colorectal cancer. Inflammation is an immunological response ...
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The purpose of research: Colorectal cancer is third most prevalent cancer in developed countries with increasing cases in developing countries. Studies show that the chronic intestinal inflammation is associated with increased risk of developing colorectal cancer. Inflammation is an immunological response to external damaging stimuli and is govern by an endogenous pyrogen and pleiotropic pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-α). TNF-α plays an important role in the development of humoral immune response. Production of TNF-α has been implicated in various other pathologies including diabetes, osteoporosis, multiple sclerosis and inflammatory bowel diseases also. Several studies have shown that anti-inflammatory effect of stigmasterol, a phytosterol of an endangered medicinal plant Chlorophytum borivilianum, is mediated by suppression of TNF-α. The latter is synthesized as a membrane-anchored precursor. The soluble form of TNF-α is released into extracellular space by tumor necrosis factor alpha converting enzyme (TACE), a multidomain metalloproteinase.
Djoko Sihono Gabriel; T. Yuri M. Zagloel; Dadang Isnandar
Abstract
Design for material value conservation in this case study was a trial implementation of design principles of plastic bag in order to minimize its value degradation and maximize its salvage value in the end of life, and therefore increase its acceptance by plastic recyclers. A Structural Equation Modelling ...
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Design for material value conservation in this case study was a trial implementation of design principles of plastic bag in order to minimize its value degradation and maximize its salvage value in the end of life, and therefore increase its acceptance by plastic recyclers. A Structural Equation Modelling (SEM) with Lisrel 8.8 software used as tool of analysis in evaluating customer acceptance of the two types of design paradigm, current and material value conservation based design. The results indicated that customer accepted both type of packaging. With final standard factor loadings, the proposed design indicated slightly better correlation coefficients: 0.46 for Ease of Information Delivery and 0.74 for Informational Content variables, better than current design with 0.44 and 0.73 coefficients. Wide spread implementation of design for material value conservation will save virgin plastic consumption for plastic packaging production, reduce plastic waste generation as well as support material resource conservation in a better condition of environment. Social and economic benefit will also be obtained as multiplier effect of material value conservation. Copyright © 2018 VBRI Press.
Rohit Sharma; Neha Khatri; Vinod Mishra; Harry Garg; Vinod Karar
Abstract
Subsurface Damage (SSD), which is introduced to optical materials by diamond turning processes, affects the performance in optical, laser and infrared applications. For optical applications, SSD can be the source of component instability (e.g., surface stress) and flaw. The objective of the present study ...
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Subsurface Damage (SSD), which is introduced to optical materials by diamond turning processes, affects the performance in optical, laser and infrared applications. For optical applications, SSD can be the source of component instability (e.g., surface stress) and flaw. The objective of the present study is to investigate the subsurface damage in silicon. Interferometry and Raman Spectroscopy are used to detect the surface finish and SSD. The surface roughness of 0.243 nm is achieved at best combination. A sharp Raman shift at 409 cm-1 is obtained, which reveals that a thin layer of Silicon has transformed to amorphous state resulting in subsurface damages. Copyright © 2017 VBRI Press.
Ramakanta Naik; C. Sripan; R. Ganesan
Abstract
In this manuscript, the As40Se60 and As50Se50 samples of 800nm thickness were deposited onto glass substrate by thermal evaporation technique. The as-deposited films were characterized using X-ray diffraction (XRD) and FTIR Spectrophotometer. The prepared samples are amorphous type. The transmission ...
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In this manuscript, the As40Se60 and As50Se50 samples of 800nm thickness were deposited onto glass substrate by thermal evaporation technique. The as-deposited films were characterized using X-ray diffraction (XRD) and FTIR Spectrophotometer. The prepared samples are amorphous type. The transmission is found to be decreased for As50Se50 film. The indirect optical transition mechanism for the photon absorption happens inside the studied film. The optical band gap is decreased with change in As and Se content. The density of state model and increase in disorder is responsible for the reduction of optical band gap in the studied films. The addition of more % As creates localised states in the gap which results the tailing of the band edges. The Urbach energy which gives the degree of disorder changes that indicates the more disorderness of As50Se50 than As40Se60 film. The XPS As3d, Se3d core level spectra variation infers the optical changes in the film and such type of film can be used for optical materials and optoelectronics.
M. Gurubhaskar; Narayana Thota; A.C. Kasi Reddy; Y.P. Venkata Subbaiah
Abstract
Tin mono-sulfide thin films were prepared using a two-step process consisting of DC sputtered deposition of Sn precursors over glass substrate held at 150 oC, followed by sulfurization for 1 hour at different temperatures ranging from 250 oC to400 oC. The influence of the sulfurization temperature on ...
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Tin mono-sulfide thin films were prepared using a two-step process consisting of DC sputtered deposition of Sn precursors over glass substrate held at 150 oC, followed by sulfurization for 1 hour at different temperatures ranging from 250 oC to400 oC. The influence of the sulfurization temperature on resultant films was studied in terms of its structure, morphology and opto-electronic properties. X-ray diffraction study revealed that the films sulfurized at lower temperature (~250 oC) had prominent SnS2 phase in addition to SnS. A single-phase tin mono-sulfide planes corresponding to orthorhombic structure has been observed at 300 oC and found to be highly crystalline at 350 oC. Further, three distinct Raman modes observed at 95, 190 and 218 cm-1 for Sn precursors sulfurized at 350 oC, strongly supporting the formation of single phase SnS. The optimized SnS film showed a direct band gap of 1.35 eV with an absorption coefficient of 5 x 104 cm-1. The valence states of Sn (+2) and S (-2) determined from X-ray photoelectron spectroscopy analysis for Sn precursors sulfurized at 350 oC, indicating the existence of SnS. These films had stoichiometric atomic ratio of Sn/S ~ 1 with surface roughness of 20 nm. All the films have shown p-type conductivity and the Sn precursors sulfurized at 350 oC exhibited relatively high conductivity of 0.947 x 10-2 (Ω cm)-1. The optoelectronic properties of SnS films reported in the present work would be highly suitable for device fabrication and promising as an alternative absorber for thin film solar cells. Copyright © 2017 VBRI Press.
Isha Saini; Annu Sharma; Naveneet Chandak; Sanjeev Aggarwal; Pawan K. Sharma
Abstract
Silver (Ag) nanoparticles play a significant role in nanomaterials science and technology due to many peculiarities. One of the main characteristic of Ag nanoparticles is the occurrence of surface plasmon resonance (SPR) due to the collective oscillation of free electrons in visible region. Due to this ...
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Silver (Ag) nanoparticles play a significant role in nanomaterials science and technology due to many peculiarities. One of the main characteristic of Ag nanoparticles is the occurrence of surface plasmon resonance (SPR) due to the collective oscillation of free electrons in visible region. Due to this distinctive feature Ag nanoparticles have numerous applications such as in catalysis, surface enhanced Raman spectroscopy, photonics, solar cells etc. In the present work, no additional stabilizing agent has been used. The characteristic SPR peak appears at around 405 nm in UV-Visible absorption spectra of PVA-Ag nanocomposite films, thereby confirming the nanocomposite formation. The synthesized nanocomposite films were structurally characterized using fourier transform infrared (FTIR) and Raman spectroscopy. FTIR spectra of PVA-Ag nanocomposite film indicates that PVA matrix is modified by Ag nanoparticles which is in agreement with the results obtained using Raman spectroscopy. TEM as well as FE-SEM micrographs reveal that Ag nanoparticles are mostly spherical in shape. The knoop microhardness number of the nanocomposites was found to increase from 2.4 Kgf/mm2 for PVA to 12.1 kgf/mm2 for PVA-Ag nanocomposite film loaded with 0.062 wt% Ag nanoparticles. Copyright © 2018 VBRI Press.
Sudha C. Angadi; Lata S. Manjeshwar; Tejraj M. Aminabhavi
Abstract
Nanocomposite microspheres of chitosan (CS) with magnesium aluminum silicate (MAS) and enteric coated with poly(vinyl acetate phthalate) (PVAP) have been prepared and examined for controlled release (CR) of capecitabine, an anticancer drug. The microspheres have been characterized by X-ray diffraction ...
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Nanocomposite microspheres of chitosan (CS) with magnesium aluminum silicate (MAS) and enteric coated with poly(vinyl acetate phthalate) (PVAP) have been prepared and examined for controlled release (CR) of capecitabine, an anticancer drug. The microspheres have been characterized by X-ray diffraction (XRD) to study the drug distribution, DSC to understand thermal stability and Fourier transform infrared (FTIR) spectroscopy to investigate the chemical interactions as well as to assess the structures of drug-loaded formulations. Surface morphology of the microspheres was investigated by scanning electron microscopy (SEM). The size distribution of the formulated microspheres studied by particle size analyzer was in the range of 303-350 μm, while their encapsulation efficiencies ranged from 50 to 58%. Equilibrium swelling of the microspheres was measured in both pH 1.2 and 7.4 media. In vitro release of capecitabine has shown a dependence on polymer-clay composition, amount of crosslinking agent and extent of enteric coating. The formulations extended the release of drug up to 32 h. The enteric coating with PVAP effectively reduced the burst release of the drug in gastric pH medium. The present method offers promising results for controlled release of short-acting drugs. Copyright © 2018 VBRI Press.
Sachin K. Srivastava; Parthasarathi Gangopadhyay; S. Amirthapandian; P. Magudapathy; Shyamala R. Polaki; Binay K. Panigrahi; T. N. Sairam
Abstract
Au nanoparticles onto a silica-glass (SiO2) surface have been formed due to thermal dewetting of Au thin films. Subsequently, high energy Si ion-irradiations on the pristine Au nanoparticles result systematic redshifts of optical responses and concomitant broadening of the optical absorption peaks with ...
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Au nanoparticles onto a silica-glass (SiO2) surface have been formed due to thermal dewetting of Au thin films. Subsequently, high energy Si ion-irradiations on the pristine Au nanoparticles result systematic redshifts of optical responses and concomitant broadening of the optical absorption peaks with the increase of ion doses. Essentially, these phenomena have been explained in the light of ion-beam mixing and transient molten-state diffusion process of Au atoms in the underneath SiO2 substrate. Analysis of high resolution electron microscopy and Rutherford backscattering data have corroborated the ion-beam induced mixing of Au atoms with the silica glass. Copyright © 2017 VBRI Press.
Meena Kumari; Manju Sikarwar; U.P. Verma
Abstract
In this paper DyMg alloy has been studied in three phases viz. B1, B2 and B3. The exchange correlation potential within the generalized-gradient approximation (GGA) of projector augmented wave (PAW) method is used. The predicted lattice constants and total energy at ambient condition, respectively ...
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In this paper DyMg alloy has been studied in three phases viz. B1, B2 and B3. The exchange correlation potential within the generalized-gradient approximation (GGA) of projector augmented wave (PAW) method is used. The predicted lattice constants and total energy at ambient condition, respectively in B1, B2 and B3 phases are 6.395, 3.772, 6.40 Å, and -24734.778, -24734.855, -24734.683 Ry. From the calculations it is evident that ground state phase of DyMg is B2, therefore, other parameters such as the bulk modulus, its pressure derivative, elastic constants and thermal properties related to B2 phase are presented in this paper. The obtained results are compared with the available experimented and theoretical data. The calculated band structure shows that this alloy no band gap. In order to obtain more information about the elastic properties other parameters such as Zener anisotropy factor, Poisson ratio, Young’s modulus and isotropic shear modulus are also presented. Thermal parameter such as Debye temperature, specific heat, Gruneisen parameter etc. has been determined as a function of pressure and temperature. Copyright © 2017 VBRI Press.
Smriti Arora; Ritika Nagpal; Sweta Mishra; SMS Chauhan
Abstract
A fast, sensitive, label-free, and organic cationic dye adsorbent has been developed by hydrothermal sulfonation reaction on reduced graphene oxide. The layered graphene sheet provides a significant surface area, high intrinsic mobility while presence of –SO3H groups on both sides of sheet render ...
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A fast, sensitive, label-free, and organic cationic dye adsorbent has been developed by hydrothermal sulfonation reaction on reduced graphene oxide. The layered graphene sheet provides a significant surface area, high intrinsic mobility while presence of –SO3H groups on both sides of sheet render strong hydrophilicity and good dispersibility in water. The dye adsorption process is followed using UV–Visible spectroscopy, while the material before and after adsorption has been characterized by Raman, Powder XRD, FT-IR, TGA, TEM, SEM analysis. Optimum experimental parameters were determined to be acidic for Rhodamine B (RB) and basic for Methylene Blue (MB), temperature 30°C, adsorbent dosage50 mg/L. The sorption equilibrium data were modeled using various isotherms, where the data best fitted to Freundlich isotherm for RB (qmax = 76.68 mg/g), while Langmuir isotherm for MB (qmax = 564.97 mg/g). The results indicate that the heterogeneous adsorbent can be applied for efficient dye removal from industrial effluent and contaminated natural water. Copyright © 2017 VBRI Press.
Hao Xin; Huigao Chen; Jiarong Lu; Junkun Tang; Qiaolong Yuan; Farong Huang
Abstract
A Si-containing arylether arylacetylene resin, poly(dimethylsilyene-ethynylene-phenyleneetherene-ethynylene) (PSEE), was synthesized from diethynyldiphenyl ether and dichlorosilane through Grignard reactions. The structures and properties of PSEE resin were characterized by NMR, FT-IR, DSC, TGA analysis ...
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A Si-containing arylether arylacetylene resin, poly(dimethylsilyene-ethynylene-phenyleneetherene-ethynylene) (PSEE), was synthesized from diethynyldiphenyl ether and dichlorosilane through Grignard reactions. The structures and properties of PSEE resin were characterized by NMR, FT-IR, DSC, TGA analysis techniques. PSEE resin can be crosslinked to form a thermoset at a temperature less than 2000C. There is no glass transition in the temperature range of RT~5000C and Td5 is 5680C in N2 for PSEE thermoset. The thermoset shows good dielectric properties and its glass fiber reinforced composite exhibits high mechanical properties. Copyright © 2017 VBRI Press.
Ekta R. Raut; Aruna M. Sudame; Manoj D. Shanti
Abstract
In today’s world plastic is a part of everyone’s life. According to American Chemistry Council primary data source, plastics generation was 35.4 million tons in 2017 in the United States, which was about 13.2 percent of total Municipal Solid Waste generation. Plastics makes thousands of products ...
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In today’s world plastic is a part of everyone’s life. According to American Chemistry Council primary data source, plastics generation was 35.4 million tons in 2017 in the United States, which was about 13.2 percent of total Municipal Solid Waste generation. Plastics makes thousands of products that add convenience, comfort and safety. Due to its light weight, strength and easily mouldable ability it is used as an ideal packaging material. It is also used in many sports to increase athlete efficiency and safety. It increases the efficiency and hygiene of medicines. It is also used in making surgical instruments. Inspite of its many advantages one of the biggest disadvantage is, it will take 1000 years to decompose in Landfills. When it burns, it produces toxic gases which adds to environmental pollution. Plastics, when it dumped in water bodies it threats aquatic life. Plastic does not allow the rainwater to seep into the ground. However, the plastic bags negatively affects environment and human health. 18 states have banned single-use plastic bags such as Maharashtra, Tamil Nadu and Madhya Pradesh. In most of the countries, bags of thickness of less than 50 microns are banned. In order to study the awareness about single use plastic ban in Nagpur City, we conducted survey of some Hotels, Restaurants, Vegetable markets and Grocery
Devendra S. Raghuvanshi; Jyotsna S. Meshram
Abstract
The green and efficient procedure for the preparation of substituted bis-indolyl methane via condensation of indole with various aryl aldehydes (3 MCR) in the presence of catalytic amount MFA (Modified Fly Ash; a zeotype catalyst) at reflux temperature in good to excellent yield (85-95%) is reported. ...
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The green and efficient procedure for the preparation of substituted bis-indolyl methane via condensation of indole with various aryl aldehydes (3 MCR) in the presence of catalytic amount MFA (Modified Fly Ash; a zeotype catalyst) at reflux temperature in good to excellent yield (85-95%) is reported. This method is utilizing the solvent free condition with the beneficial features such as short reaction time and easy process for isolation. The rate of reactions is found to relay on EDGs and EWGs substituents present on aryl aldehydes at particular positions.
B. Kalpana; R. Nanthini
Abstract
A novel random copolyester Poly(1,4-dithiane-2,5-diol Succinate – Co – 1,2-ethane diol Succinate) PDES containing sulphur atom was synthesised by direct melt polycondensation method using 1,4- dithiane-2,5-diol as a special monomer, succinic acid, and 1,3 ethane diol with Titanium tetra isopropoxide ...
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A novel random copolyester Poly(1,4-dithiane-2,5-diol Succinate – Co – 1,2-ethane diol Succinate) PDES containing sulphur atom was synthesised by direct melt polycondensation method using 1,4- dithiane-2,5-diol as a special monomer, succinic acid, and 1,3 ethane diol with Titanium tetra isopropoxide as catalyst. The wide range of application of the special monomer especially as biocontrol material and food additive led us to extend our area of research towards producing copolyester with cytotoxic activity. The various physical properties of the copolyester such as inherent viscosity, glass transition temperature, solubility and crystalline nature was investigated and studied in detail.The 1H-NMR and FT-IR was done to investigate the chemical properties of the PDES copolyester.In Vitro cytotoxicity against Normal (Vero cell line) and cancer (A549 Lung cancer cell line) by MTT Assay, Antioxidant activity by Dot-Blot/DPPH scavenging Assay and Antimicrobial by Well diffusion method studies proved that the synthesised copolyester have immense biological properties and could be used in biomedical application.
Rajat K. Saha; Mrinal K. Debanath; Eeshankur Saikia; Vedant V. Borah; Kandarpa K. Saikia
Abstract
ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the ...
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ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the XRD data obtained, by using the tools of Nonlinear Dynamical Theory (NLD). One of the tools used called Lyapunov Exponent, bears the signature of the dynamical evolution of the particles as well as structure formation. This is calculated in order to quantify the underlying strange attractor present in the nanosystems, which happens to be the driving force behind the structure formation. The changes in the values of this parameter with the variation of the physical and chemical conditions, would pave the way for an efficient calibration for meaningful biological applications, which happens to be the focus of the present work. Differently sized ZnO nano particles are obtained by changing dopant percentage for inhibiting human pathogenic bacteria. Calibrations are made between the Zone of Inhibition (ZOI) and Lyapunov Exponent to obtain the required dopant percentage for a given ZOI vis-à-vis the same anti-bacterial effectiveness in terms of ZOI of a ZnO doped nano particle. Copyright © 2016 VBRI Press.
M.K. Debanath; R.K. Saha; S.M. Borah; E. Saikia; K.K. Saikia
Abstract
In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized ...
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In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive analysis of X-rays (EDAX), high resolution transmission electron microscopy (HRTEM), UV-vis absorption spectroscopy and photoluminescence (PL) spectroscopy for their structural and optical properties. Antibacterial properties have been studied by Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria. XRD study showed hexagonal wurtzite crystal structure of the prepared ZnO:Cu and nanoformation of the as-synthesized NPs. Nanoparticle formation have been finally confirmed by HRTEM analysis. Antibacterial studies showed excellent resistance of ZnO:Cu to S. aureus and E. coli respectively. Copyright © 2018 VBRI Press.
Maykon Christian Meneghel; Percy Nohama; Guilherme Nunes Nogueira Neto
Abstract
Accidental falls may occur in the elderly, especially older than 65 years. Among the intrinsic factors that corroborate this fatality are the physiological changes resulting from the aging process. Factors such as inadequate lighting, uneven ground, or some obstacles along the way also contribute to ...
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Accidental falls may occur in the elderly, especially older than 65 years. Among the intrinsic factors that corroborate this fatality are the physiological changes resulting from the aging process. Factors such as inadequate lighting, uneven ground, or some obstacles along the way also contribute to falls. The literature indicates most falls occur in the domestic environment. In some cases, falls can cause serious injuries, such as bone fractures and head injuries. In these cases, intervention time to treat a person who has fallen is crucial. In this study, we developed a Wi-Fi fall detector buckle to be used indoors at waist height by the elderly. For testing purposes, we assumed a simple detection threshold that identifies a fall whenever the absolute value recorded by the accelerometer is greater than 2.3 g and the angle formed between the y-axis and the vertical sagittal axis of the buckle device is greater than 60°. The device is functional, adjustable, flexible and inexpensive. It is functional because it can differentiate falls from ADL with 84.1% accuracy, adjustable because it allows to change the fall detection threshold, flexible for including new detection algorithms and cheap because it uses components available in abundance in the market.
A.V. Tyunkov; Yu.G. Yushkov; D.B. Zolotukhin; E.M. Oks; D.A. Golosov; S.M. Zavadsky
Abstract
This paper demonstrates the possibility of nitriding of titanium by a forevacuum electron source. We present an original design of the experimental setup and the measurements of the tribological properties and elemental composition of the subsurface layer of the titanium experimental sample. Raster electron ...
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This paper demonstrates the possibility of nitriding of titanium by a forevacuum electron source. We present an original design of the experimental setup and the measurements of the tribological properties and elemental composition of the subsurface layer of the titanium experimental sample. Raster electron microscopy analysis of the nitride sample have demonstrated that titanium and nitrogen are found to be the main chemical elements; oxygen and carbon also present, though their total concentration does not exceed 6 wt. %. The thickness of the modified layer after a 75-minute long process of nitriding was about 8 µm. Wear resistance test of have shown that the nitrided sample has a 500 times less loss of the material as compared with the original titanium sample, meaning a times-fold increase of resistance to wear.
Hemalata Jena; Arun Kumar Pradhan; Mihir Kumar Pandit
Abstract
The present study attempts to explore the possibilities of utilising industrial waste as filler material in bamboo fibre reinforced composites. Cenosphere, a mixture of alumina and silicon rich industrial waste produced during burning of coal in thermal power plants, is used as filler material in this ...
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The present study attempts to explore the possibilities of utilising industrial waste as filler material in bamboo fibre reinforced composites. Cenosphere, a mixture of alumina and silicon rich industrial waste produced during burning of coal in thermal power plants, is used as filler material in this study. It's use in composites would address environmental and economic concern arising in storage and handling of enormous quantity of waste discharged by the thermal power plants. In order to determine the heat insulation property of this polymer composites with varying bamboo fibre (18, 28, 33, 43 wt%) and cenosphere filler (0, 2.5, 3, 4.5, 6 wt%) content, thermal conductivity test is performed by using Lee’s disc apparatus. Experimental results reveal that with the increase in fibre loading, the thermal conductivity of the composite decreases and it is minimum at 43 wt% of fibre. It is also found that introduction of cenosphere fillers on bamboo fibre reinforced composite results in further reduction of its thermal conductivity. Hence improved thermal insulation property of these composites can be gainfully utilised in insulation application. The thermal conductivity of these composites is also evaluated by using Finite Element Method, which is in good agreement with that of experimental results. The test results for thermal conductivity are also in good agreement with various models available in the literature. Copyright © 2017 VBRI Press.
Nidhi Puri; Raj K. Gupta; Akhyaya K. Pattanaik; Navin C. Mehra; Ajit K. Mahapatro; Ram P. Tandon
Abstract
The present paper highlights the synthesis of cobalt antimonide (CoSb3) micro/nanostructures by following solvothermal technique with water as solvent. Recipe is optimized for preparation of refined CoSb3 compounds and demonstrated that a high processing temperature of 500 °C and long duration of ...
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The present paper highlights the synthesis of cobalt antimonide (CoSb3) micro/nanostructures by following solvothermal technique with water as solvent. Recipe is optimized for preparation of refined CoSb3 compounds and demonstrated that a high processing temperature of 500 °C and long duration of 72 hr indicates presence of CoSb3 phase. The microstructures and composition of the as synthesized CoSb3 nanocomposites are characterized to achieve the optimized phase.The morphologies as imaged using field emission scanning electron microscope resemble granules for the as-synthesized CoSb3. The phase purity and crystallographic structure of the as-synthesized CoSb3 nanocomposites as determined by XRD indicates the formation of the cubic phase of CoSb3 and agrees well with the JCPDS data mentioned for the highly pure CoSb3. The EDX estimates the elemental composition of Co and Sb in 1:3 stoichiometric ratio for the as-synthesized CoSb3. The currently prepared nanosized skutterudite CoSb3 material synthesized by solvothermal method could be utilized as active material for the development of highly efficient thermoelectric devices. Copyright © 2018 VBRI Press.
Rakesh Saroha; Aditya Jain; A. K. Panwar
Abstract
The effects of ZnO nanoparticle coating on the physicochemical and electrochemical properties of LiFePO4 (LFP) have been investigated in this work. ZnO-modified LiFePO4 cathode materials were synthesized via sol-gel and modified by ZnO nanoparticle using ball mill method. The amount of ZnO additive is ...
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The effects of ZnO nanoparticle coating on the physicochemical and electrochemical properties of LiFePO4 (LFP) have been investigated in this work. ZnO-modified LiFePO4 cathode materials were synthesized via sol-gel and modified by ZnO nanoparticle using ball mill method. The amount of ZnO additive is chosen as a controlling factor to tune ZnO content over the surface of LFP particles. Structure and morphology of the LFP material with and without ZnO-coating layer were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. The XRD patterns reveal that the proper phase of LFP is formed with the ordered olivine-type orthorhombic structure of Pnma space group, and no impurity phase like LiZnPO4 has been noticed. AC conductivity measurements have shown that the ZnO-modified LFP samples significantly assists in lowering the resistance of cathode active material and enhancing the conductivity. It is found that the 2.5 wt% ZnO-doped LFP exhibits the highest conductivity than the 5 wt% ZnO and 1 wt% ZnO doped LFP or the un-doped sample. Among the synthesized samples, LFPZ2.5 displays highest discharge capacity 160 (±5) mAhg-1 (~94% of the theoretical capacity of LiFePO4) at 0.1C rate. These results indicate that 2.5 wt% ZnO coated pristine LFP sample proves to be alternative material for automotive industry and it may be possible alternate of cathode materials in hybrid electric vehicles. Copyright © 2016 VBRI Press