A novel approach in fabrication of a hybrid green metal matrix composite using waste egg shells and snail shell ash as reinforcements |
Author : Soutrik Bose, Deep Mondal, and Subhayu Sar |
Abstract | Full Text |
Abstract :The effective utilization of biowaste is mandatory for sustainability of our society. The aluminum (Al) alloy is reinforced with different volume fractions of silicon carbide (SiC), waste carbonized eggshells (WCE) and snail shell ash (SSA) and fabricated by stir casting process. To manifest the global need of novel hybrid composites with reduced weight, high strength and cost effectiveness, this paper leads to the development of a new hybrid composite. Experimental results
shows increased hardness, tensile and fatigue strength while decrease in fracture toughness, ductility and corrosion rate which is improved by heat treatment. The optimum values are obtained at 12.5 wt. % of WCE and 7.5 wt. % SiC+SSA. The samples are kept stable and non-reactive at most favorable
temperature. Mono-ethylene glycol (MEG) in aqueous solution is used for the experiments. The hardness is augmented to a maximum value at 7.5 wt. % SiC+SSA addition and gets decremented at 10 wt. % SiC+SSA addition. Microstructures of composites show uniformity in interfacial bonding and distribution of WCE. Density and overall cost of the composite are decreased which infer improvement of mechanical properties with the addition of WCE particulates. |
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Application of a polytrimethoxysilane based molecularly imprinted polymer (MIP) electrode towards discrimination of different types of turmeric powder |
Author : Saumita Kar, Hemanta Naskar, Bipan Tudu, Rajib Bandyopadhyay |
Abstract | Full Text |
Abstract :The major bioactive component of turmeric (Curcumina longa) is a phenolic compound named curcumin which is anti-oxidant, anti-inflammatory, anti-cancer having many more biological
applications. In this work a extremely responsive molecularly imprinted polymer-modified carbon paste electrode (MIP-CPE) has been developed to detect curcumin content of turmeric powder. The molecularly imprinted electrode was made with the template molecule as curcumin and functional monomer as trimethoxysilane. This monomer has an excellent property to undergo polymerization without requiring any external cross linker. The customized electrode was prepared by combining the polytrimethoxysilane, graphite powder, and paraffin oil in some definite patterns. The electrochemical behavior of curcumin was studied by this electrode and a technique for straight curcumin detection in turmeric powder by the use of this electrode was done. The outcome shows that curcumin exhibits distinctive oxidation peaks at about 0.4 V and 0.7 V when phosphate buffer solution (PBS) of pH 6 was used. The cyclic voltammogram in the concentration range of 1-100 µM shows that the concentration and the corresponding current values were linearly related to each other. Multivariate data analysis after pre-processing was applied on the signals obtained by cyclic voltammetry for five different types of
turmeric powders. For exploratory data analysis radar plot, box plot, PCA (principal component analysis) and LDA (linear discriminant analysis) were done which reflects a good result. |
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Tribological properties of natural fiber hybrid reinforced polymer composite |
Author : Debasmita Pani and Punyapriya Mishra |
Abstract | Full Text |
Abstract :In present scenario natural fibers are abundantly being utilized for production and improvement of composites with polymer matrices. In the present work produced mat/woven structure
of Luffa cylindrica (loofah), coconut coir (medially coarse and fine) particulates and short bagasse fibers from the rind of sugarcane were utilized to form hybrid polymer composites with epoxy matrix. The fabrication was done with mercerized natural fibers in epoxy matrix by hand-layup technique. Experiments were conducted to examine erosive wear properties of fabricated composites using an airjet erosive wear tester at room temperature. A steam of silica sand is chosen as the erodent striking the composite specimens with different impact velocities and pressures for an exposure period of 10 minutes. The erodent geed rate is kept constant. The impingement angle is set at 300, 450, 600 and 900. The erosion rate was calculated in each case to study their tribological properties. |
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Discrimination of green tea using an Epigallocatechin-3-gallate (EGCG) sensitive molecular imprinted polymer (MIP) based electrode |
Author : Debangana Das, Trisita Nandy Chatterjee, Runu Banerjee Roy, Bipan Tudu, Santanu Sabhapondit, Ajanto Kumar Hazarika, Panchanan Pramanik, Rajib Bandyopadhyay |
Abstract | Full Text |
Abstract :In this work, a simple approach of discriminating green tea samples has been proposed using an epigallocatechin-3-gallate (EGCG) sensitive molecular imprinted polymer (MIP) electrode modified with chemically synthesized nickel hydroxide (Ni(OH)2) nanoparticles. The nanoparticles were characterized by powder X-ray diffraction techniques (XRD) and the removal of the template molecule has been ascertained by UV-vis spectroscopy. A three electrode system has been employed to study the electrochemical characteristics of the electrode by means cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Four different kinds of preprocessing techniques, namely – (i) Baseline subtraction, (ii) Autoscale, (iii) Relative scale 1 and (iv) Relative scale 2 were applied on the obtained data set and the best preprocessing technique was optimized. Further, principal component analysis (PCA) and linear discriminant analysis (LDA) were implemented on the preprocessed data set so as to observe the discrimination ability of the electrode on the basis of EGCG content in green tea. The separability index (SI) values for both PCA and LDA plots is calculated and it is observed that baseline subtraction provided the best result with a SI value of 8.72 and 16.01, respectively. |
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Electronic and optical properties of B-N doped carbon nanotubes and graphene: A first principles Study |
Author : Debnarayan Jana, Arka Bandyopadhyay |
Abstract | Full Text |
Abstract :2D materials as well as quasi-1D materials exhibit fascinating optical and electronic properties. Boron (B) and nitrogen (N) doping are of particular interest due to their expected
modification of electronic hence optical properties. We have performed density functional theory (DFT) computations in the low frequency limit to calculate the band structure and dielectric constant of the B-N doped single wall carbon nanotubes (SWCNT) systems. Graphene sheet has been doped with individual B, N atoms along with the simultaneous B-N codoping
with varying concentrations. Controllable band gaps have been observed to be induced in the systems for different concentrations of three different foreign species. Besides, the Raman spectrum of the B/N doped Tetragonal graphene (T-graphene) systems has been computed for
characterization purpose. Among transition metals, doped in T graphene system, Sc shows significant spin polarization. Further, the electronic structure and the relevant density of state (DOS) at Fermi energy of B-N doped T-graphene can be judiciously used for the electronic transport. Our theoretical results will serve as an important reference to fabricate various optoelectronic devices with nanoscale dimensions using B/N substitution in the carbon network. |
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Glassy carbon as a novel mould material for replicative forming of precision glass optics. |
Author : Biplab Kumar Paul and Dipayan Sanyal |
Abstract | Full Text |
Abstract :Replicative forming of precision glass optics has been fast emerging as a rapid, net shape process chain for mobile camera lenses, CD/DVD pickup lenses, microscope objectives, night vision lenses, Fresnel lenses and so on. The process involves moulding a glass gob at high temperatures exceeding the glass transition temperature using a predefined loading and thermal
cycle. Typically, the mould material is required to have high strength, low thermal expansion, chemical inertness and anti-adhesion properties, especially at high temperatures. Traditional mould materials, such as, invar or tungsten carbide are difficult to machine which adversely affects the cost of the entire process. In the present work, glassy carbon mould has been developed using p-tolune sulfonic acid (PTSA) cured phenolic resin by a process of carbonization where the composition ratio of phenolic resin and PTSA solution was standardised accompanied by the pyrolysing conditions. Detailed characterisation of the phase evolution, surface compositions, morphology and mechanical parameters of the glassy carbon has been conducted by X-Ray diffraction (XRD) technique, Raman Spectral (RS) analysis, X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron microscope (FESEM), Energy Dispersive Spectroscopy (EDX) and Nanomechanical testing which reveal an optimal combination of properties of the glassy carbon that makes it an attractive low cost mould material for replicative forming process chain of glass optics fabrication. |
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Synthesis of ß, ?- PVDF through electrospinning for piezoelectric force sensing application |
Author : Shubhanwita Saha and Dipayan Sanyal |
Abstract | Full Text |
Abstract :: In the present study, PVDF nanofibers containing ß and ?-phases have been synthesized by electrospinning process. An experimental study was conducted for evaluating the
high temperature effects on sample precursor preparation as well as PVDF phase transition (a=>ß phase and a=> ? phase). High temperature melting process was employed to prepare
PVDF solution as precursor for electrospinning and a typical process condition was maintained to draw PVDF nanofiber. Synthesized fibers were characterized by fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM) and X-Ray diffraction (XRD). To measure the sensing performance of the PVDF nanofibers, a piezoelectric
force sensor device was constructed using these fibers. The voltage vs current and voltage vs time signals were recorded against calibrated loads using digital oscilloscope. More specifically, it was established that precursors melted at 150°C temperature is essential for producing ß+? mixed crystal based PVDF nanofibers which could generate signals of sufficiently high amplitude at low applied forces consistent with the physical acoustic theory. |
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Synthesis of ultra-high temperature silicon oxycarbide (SiOC) glass by an organic-inorganic hybrid route |
Author : Biplab Kumar Paul, Karthiga Parthiban, Saheli Bhattacharya, Dipayan Sanyal |
Abstract | Full Text |
Abstract :Silicon oxycarbide is a new generation amorphous glassy ceramic possessing unique electrical, mechanical, optical properties and ultra-high temperature stability upto 2730°C. It has numerous engineering applications in additive manufacturing, lithium-ion batteries, brake disks for sports car, ultra-fast and high voltage LEDs, MOSFETs, thyristors for high power switching, astronomical telescope, nuclear power reactor etc. In this work, SiOC was prepared by sol-gel technique using organic-inorganic hybrids as precursors. Tetraethoxysilane (TEOS) and Polydimethylsiloxane (PDMS) were used as silica and carbon sources respectively. SiOC sols were formed through hydrolysis of TEOS and PDMS. The used chemicals in this process involved isopropanol, distilled water and hydrochloric acid, which is used here as solvent, hydrolytic agent and catalyst respectively, at different refluxing condition, alkoxide to water ratios, pH levels etc. The sols thus formed were allowed to gel over a varying period (upto maximum of 10 days). After drying the gels for 24 hours, the same was pyrolysed at 1100°C under inert nitrogen atmosphere to yield SiOC. Phase formation was carried out by X-Ray Diffraction (XRD) technique, X-ray Photoelectron Spectroscopy (XPS) analysis and Raman Spectroscopic analysis. XRD data showed formation of a broad peak at 2?~22 degrees indicating formation of amorphous SiOC and absence of any crystalline peaks indicating no SiC or Si was formed during pyrolysis. XPS data shows the presence of Si, O and C peaks in the range 100-200 eV, 530 eV and 285 eV, respectively, confirming formation of SiOC. It was revealed that within the random network of Si-O tetrahedra, islands of only C-C bonds were responsible for coloring the SiOC glass black. The estimation of mechanical properties revealed that the hardness value and Young’s modulus, of the synthesized SiOC ceramic sample, was
determined to be 11.67 GPa and 75.79 respectively which indicating the better mechanical properties than other reported SiOC systems. |
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Role of Mo substitution on electric modulus and electrical conductivity of cobalt-zinc spinel ferrite |
Author : A. K. Pradhan, S. Saha, T. K. Nath |
Abstract | Full Text |
Abstract :Cobalt- Zinc ferrites are presently utilized as a significant component material for fabricating multiferroic composite. Conventional ceramic technique was utilized to synthesize
the bulk cobalt-zinc ferrite with Mo substitution (CZFMO). In this present article, we accounted for the study of detail electric modulus and electrical conductivity of Co0.65Zn0.35Fe2-xMoxO4 (x=0.0, 0.1 and 0.2) spinel ferrites. The production of the inverse spinel nature of the material structure has been affirmed by the high resolution XRD pattern. The frequency reliance of real and imaginary part of electric modulus have been studied in detail. In the present framework the behavior of electric modulus could be communicated by the modified Kohlrausch-WilliumsWatts (KWW) equation. The variation of the imaginary part of electric modulus (M") with frequency indicates the existence of non-Debye relaxation process in the current samples. The curves showing the variation of ac conductivity with frequency follow the Jonscher’s single power equation. This suggest that the conduction in the material is due to correlated barrier hopping (CBH) mechanism. Additionally, the conduction procedure can be best clarified based on Verwey-de Boer method. The activation energy in both ferromagnetic and paramagnetic area is assessed from the ln sac vs. 1/T curves. The temperature reliance of dc conductivity obeys the
Arrhenius expression. Also the semiconducting nature of material has confirmed from the conductivity plot. |
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Optimization of stable recipe of semi interpenetrating polymeric network based on the diffusivity and swelling percentage |
Author : Pritha Biswas, Somasri Hazra, Ruma Maity, Baishali Kanjilal, Haimanti Chakrabarti |
Abstract | Full Text |
Abstract :The hydrophilic nature of semi interpenetrating polymeric network hydrogels (SIPN) bestows a wide spectrum of applications of such systems establishing it as a remarkable material in polymer technology. A SIPN of Polyacrylamide and Glutaraldehyde mediated crosslinked Poly Vinyl Alcohol can be synthesized with variety of combinations of the basic constituents with variable state parameters. In this work we report the fabrication of SIPN matrix hydrogel prepared as small cylinders of length about 2.0 cm and diameter about 0.8 cm in which the constituents are varied in a sequential manner to attain the optimum parametric condition of state of Acrylamide, Glutaraldehyde and Poly Vinyl Alcohol established on the basis of water transport properties based on the diffusivity and swelling percentage studies of the SIPN
prepared. We believe this study will pave the way to a new methodology to achieve optimum conditions of precursors in SIPN. |
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A Comparative analysis of steep retrograde and uniform doping for high-k dielectrics based multi-gate devices |
Author : Rajiv Ranjan Thakur, Pragati Singh |
Abstract | Full Text |
Abstract :A brief comparison has been done for the uniform doped and steep retrograde doped MultiGate Devices with High-k Dielectric Oxide Layer in comparison with the traditional Silicon Dioxide
Oxide Layer. Analytical modeling has been done for the steep retrograde doping and it has been found that the effects of Threshold Voltage (Vth) Roll-Off have been suppressed up-to certain extent using Steep Retrograde Doping. The study also predicts that Hafnium Dioxide can be very good alternatives to
the traditional gate oxide as it greatly suppresses high leakages and other problems. The device was carried out using Sentaurus 3D-TCAD Tools. |
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Molecular docking studies using garlic metabolites - a peek into the apoptotic pathway |
Author : Shilpa Bose and Ruchira Mukherjee |
Abstract | Full Text |
Abstract :The organosulfur compounds derived from Garlic employ cytotoxic effects via (ROS) reactive oxygen species production for signaling, by activating cysteine proteases and stress kinases for apoptosis in human cancerous cell. With the increase in mitochondrial membrane permeability due to
stress, the intracellular free [Ca2+] level increases. Thus, the activation of caspase-4 alongwith the expression of calreticulin indicates the involvement of (ER) endoplasmic reticulum stress in the process of apoptosis. Down-regulation of some BIRC proteins and Bcl-2, activation of Caspase3, Caspase-9 and
Calpain, mitochondrial release of cytochrome c and Smac into the cytosol and overexpression of Bax are the related events included in apoptosis. In this work, homology modeling approach was employed in order to develop structures for these proteins. Some protein structures were readily available in the PDB database. Expasy’s Prot-param server were used for functional and physico-chemical characterization of the protein. Chemsketch was used for drawing molecules and ligands. Babel is the software used to convert .mol files to .pdb files for docking. Autodock software was used to dock ligands with their
respective proteins, Patchdock and Firedock was also used to determine Protein-Protein interaction. Docking was performed to evaluate the binding constants of the different interactions mediated by garlic in the apoptotic pathway. |
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