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Enhanced energy storage performance of nanocrystalline Sm- doped CoFe2O4 as an effective anode material for Li-ion battery applications
No full textA simple modified combustion method was demonstrated in the development of cobalt ferrite (CoFe2O4) and samarium (Sm)-
doped CoFe2O4 nanostructures. The Sm3+-doped CoFe2O4 can significantly affect their crystallite size, lattice parameter, and
electrical and electrochemical properties. The powder X-ray diffraction analysis revealed the formation of cubic spinel CoFe2O4. The structural coordination of pristine and Sm3+-doped CoFe2O4 samples was confirmed by Raman and Fourier transform infrared spectroscopy analyses and also peak positions of Sm3+-doped CoFe2O4 sample shifted toward lower wavenumber, which may be due to the cell expansion resulting from Sm3+ doping in CoFe2O4 structure. In addition to above, X-ray photoelectron spectroscopy results clearly demonstrated the doping of Sm3+ into CoFe2O4 crystal lattice. The electrical conductivity of Sm3+-doped CoFe2O4 is one order of magnitude higher than that of pristine CoF2O4. The prepared pristine and Sm3+-doped CoFe2O4 samples were investigated as an anode material for lithium (Li)-ion batteries. The Sm3+-doped CoFe2O4 anode showed a better reversibility and rate performance than the pristine CoFe2O4 anode. Also, the Sm3+-doped CoFe2O4 electrode exhibited a stable cycling performance with a discharge capacity of 800 mAh g−1 after 150 cycles at 0.1 C and delivered a discharge capacity of 778 mAh g−1 after 400 cycles at 200 mA g−1 . The observed high electrochemical performance of Sm3+-doped CoFe2O4 electrode may be attributed to its improved structural stability and enhanced oxidation reaction which maintain the number of Li ions involved in the charge-discharge proces
Judd-Ofelt parametrization and radiative analysis of Dy3+ ions doped Sodium Bismuth Strontium Phosphate glasses
No full textThis paper focus on spectroscopic analysis of Sodium Bismuth Strontium Phosphate (NaBiSrP) glasses doped with dysprosium (Dy3+) ions using X-ray Diffraction (XRD), Raman Spectroscopy,
Fourier Transform-Infrared (FT-IR) Spectroscopy, Photoluminescence (PL) Spectroscopy and decay spectral measurements. Excitation spectra of the glasses under 575 nm emission possess a sharp band corresponding to 6H15/2 → 6P7/2 transition (350nm). Subsequently, emission spectra
recorded under 350 nm excitation exhibit sharp bands at 480 and 575 nm. The Judd-Ofelt (J-O) theory has been applied to the measured energies of the absorption bands/oscillator strengths to study various radiative parameters such as radiative and total transition probabilities (AR &AT), branching ratios (βR) and radiative lifetimes (τR) for the prominent fluorescent levels of Dy3+ doped NaBiSrP glasses. It was observed that glass D has got highest value of Ω2 signalling high symmetry of crystal field of Dy3+ ions and a maximum intensity for hypersensitive transition .PL decay analysis reveal experimental lifetimes of 4
F9/2 energy level under 350nm excitation decreases with
increase in Dy3+ ion concentration indicating the energy transfer between Dy3+ ions. The InokutiHirayama (I-H) curve fitting was also done for the glass with the highest Dy3+ ion concentration showing dipole-dipole interaction. From the above-mentioned results, it is apt to say that the as synthesized phosphate glasses doped with Dy3+ ions are quite suitable for designing the white light emitting diodes (wLEDs) and other optoelectronic devices
Design Parameters for Diesel Hydro Desulfurization (DHDS)
No full textApart from all gaseous contaminants in air, sulfur dioxide is considered to be the principal pollutant. The emission of sulfur dioxide is generally caused by combustion of sulfur bearing fuels. This further gets converted into sulfuric acid in atmosphere as a result of its reaction with oxygen and moisture. This air borne acid is responsible to damage steel buildings, bridges and machinery. Hence there is a major need to decrease sulfur percentage in the environment in order to lead a better and healthy living. As we can see the world runs on energy, for which fossil fuels are the main constituents. As these all are the complex network of hydrocarbons, when they are combusted or utilized, the products or effluents are somewhat harmful to the atmosphere. Sulfur is one such effluent, which seriously harms the environmental conditions. So this has to be recovered up to appreciable levels. In India diesel is mostly utilized as fuel and it is up to 70%. So in order to reduce the sulfur content diesel is chosen as fuel oil. The reduction of sulfur is done by hydro desulfurization and the process is termed as diesel hydro desulfurization (DHDS). This is achieved by converting the mercaptane state sulfur to hydrogen sulfide (H2S) by reacting it with hydrogen alone on a cobalt molybdenum catalyst. By this the sulfur content is reduced from 1 wt% to 0.25 wt%. This is further reduced to 0.05 wt% using trickle bed reactors.Apart from all gaseous contaminants in air, sulfur dioxide is considered to be the principal pollutant. The emission of sulfur dioxide is generally caused by combustion of sulfur bearing fuels. This further gets converted into sulfuric acid in atmosphere as a result of its reaction with oxygen and moisture. This air borne acid is responsible to damage steel buildings, bridges and machinery. Hence there is a major need to decrease sulfur percentage in the environment in order to lead a better and healthy living. As we can see the world runs on energy, for which fossil fuels are the main constituents. As these all are the complex network of hydrocarbons, when they are combusted or utilized, the products or effluents are somewhat harmful to the atmosphere. Sulfur is one such effluent, which seriously harms the environmental conditions. So this has to be recovered up to appreciable levels. In India diesel is mostly utilized as fuel and it is up to 70%. So in order to reduce the sulfur content diesel is chosen as fuel oil. The reduction of sulfur is done by hydro desulfurization and the process is termed as diesel hydro desulfurization (DHDS). This is achieved by converting the mercaptane state sulfur to hydrogen sulfide (H2S) by reacting it with hydrogen alone on a cobalt molybdenum catalyst. By this the sulfur content is reduced from 1 wt% to 0.25 wt%. This is further reduced to 0.05 wt% using trickle bed reactors
Preparation of Barium Titanate Having High Dielectric Constant from Barite ores using Precipitation, Calcination Techniques
No full textBarium titanate (BaTiO3 ) is an attractive material in the field of electro ceramics and microelectronics due to its better characteristics. It is having high dielectric constant and low loss characteristics and hence barium titanate is an excellent choice for many applications, such as capacitors, multilayer capacitors (MLCs) and energy storage devices. In the present study an attempt is made to prepare barium titanate from ore using reduction ,leaching ,precipitation and calcinations techniques.The material is giving higher dielectric constant compared to the synthetically prepared materials
RECENT STRATEGIES FOR EFFICIENT SYNTHESIS AND BIOLOGICAL ACTIVITIES OF COUMARIN-CHALCONE DERIVATIVES
Get PDFCoumarins and chalcones are potential pharmacological and biologically active molecules obtained from the natural source. Coumarins have predominant pharmacological activities such as antidiabetic, antitumor, and anti-inflammatory activity. Chalcones are also one of the naturally occurring pharmacologically vital molecules with different activities such as anti-inflammatory, antitumor, antimicrobial, and antimalarial activity. Literature reveals that a huge number of coumarinyl chalcone derivatives have various pharmacological activities. Coumarinyl chalcone derivatives gained more prominence due to their significant biological activities. This work explains the current information about synthesis techniques, pharmacological importance, and clinical applications of coumarinyl chalcone derivatives
Fe(0)-embedded thermally reduced graphene oxide as efficient nanocatalyst for reduction of nitro compounds to amines
No full textABSTRACT
The recent progress in metal nanoparticle-based catalytic systems has prompted the research community to focus
on combining the unique physicochemical properties with their catalytic activities. In this context, magnetic nanomaterials offer significant advantage as they can be separated after the catalytic reaction and reused. Among such systems, Fe-based nanoparticles are undeniably the most popular as they can be synthesized from the earth-abundant resources. However, in view of the poor chemical stability of nanoscale zero-valent iron
(nZVI) particles during the reaction process, their use in advanced catalytic systems is still challenging. Herein,
we present a Fe(0) species embedded in a thermally reduced graphene oxide matrix (Fe/TRGO) as a nanocatalyst
for the reduction of nitro compounds. The catalyst exhibits high substrate scope with high yield and selectivity
and can be recycled up to four times without any significant loss in activity. The unique rGO (reduced graphene
oxide)-entrapped doughnut-shaped structure of the Fe(0) species, accompanied by the thin oxide protection
layer, is responsible for the superior catalytic activity. Due to the scalable synthesis and high catalytic efficiency
the catalyst offers a real application potential in industrial transformations of nitro compound
Dry sliding wear behavior of Al 6082 metal matrix composites reinforced with red mud particles
No full textThe present study aims at investigating the dry sliding wear behavior of Al-based 6082 metal matrix composites (AMMCs)
reinforced with red mud particles by pin-on-disc confguration. AMMCs were fabricated with three diferent weight fractions of red mud particles ranging from 2 to 6% by using the stir-casting method. The friction coefcients and volumetric wear rates were continuously evaluated under normal loads of 10–30 N and sliding speed of 1.5 m s−1 for the constant sliding distance of 1000 m. Microstructural analysis indicated that red mud particles are more or less uniformly dispersed throughout the Al matrix with minimal agglomeration. Experimental data shows that microhardness and tensile strengths of both the as-cast and heat-treated composites are steadily improved by increasing the amount of reinforced red mud particles but at the cost of ductility. Analysis of worn surfaces revealed that delamination and abrasion are dominant wear mechanisms for the case of the heat-treated composites are whereas the adhesion wear mechanism for the base alloy. The composite containing 4% red mud particles experienced the lowest wear rate at a normal load of 30 N and sliding speed of 1.5 m s−1 as compared to other composites including the base alloy. While the composite with 2% red mud particles shows the lowest friction coefcient, base alloy exhibited the highest friction coefcien
Effect of Crack Angle on Stress Shielding in Bone and Orthopedic Fixing Plate Implant: Design and Simulation
No full textIn the present study, laminated composites of polymethyl methacrylate AQ1 1
2 (PMMA)—titanium (Ti) with different ply orientation are designed and three dif�3 ferent crack angles (20°, 40° and 50°) were considered in femur bone to investigate
the effect of crack angle on the stress distribution in the bone. PMMA was selected AQ2 4
5 as matrix and titanium was selected as fiber from 0.2 to 0.5 volume fraction (Vf).
6 3D model of bone implant assembly was designed by using computer-aided drafting
(CAD) and simulation was carried out with the help of ANSYS Workbench® 7 soft�8 ware. Laminated composites with different ply orientations with different volume
fractions of fiber were analyzed, and optimum combination was abstracted with an AQ3 9
10 objective to attain higher and uniform stress distribution throughout the bone. From
11 the results, it is observed that the crack angle effects the stress distribution in the
12 bone even though the same laminated composite is used as implant.
13 Keywords Stress shielding · Titanium · Laminated composite · PMM
A Review on the Development of Customized Ankle Foot Orthosis for Foot Drop using Additive Manufacturing Processes
No full textAnkle foot orthosis (AFO) device improves the walking ability by hold and directs the position and advancement of the lower limb, specifically ankle movement. The primary function of AFO is to correct the deformities of the damaged nerves and
compensate for the weak & paralyzed muscles. Traditional AFOs are handcrafted using plaster moulds for generating patient’s geometry, by a thermoforming process. Hence, the fabrication of a customized AFO consumes more time and expense as
well. In the current review paper, it is discussed thoroughly about the upcoming technology known as additive manufacturing and its potential application for the
production of customized AFOs. This review aimed to present the different AFOs produced by the additive manufacturing processes along with gait performances and material properties compared to the traditionally manufactured AFO
Heat Transfer Enhancement Of A Triplex Concentric Tube During Energy Storage By Using Pcm
No full textThe extremely important of Heat Exchanger (HE) is that without mixing of fluid that carries the heat. Substances that leave or absorb large amount of so-called ‘latent’ heat this type of substances are called phase change materials (PCMs) once
they undergo a change in their physical state i.e. from solid to liquid and contrariwise. This paper addresses a CFD analysis of phase change materials in thermal energy storage units dominated by heat condition. The result states that by
utilization of PCM, the temperature is increment identified in counterflow whereas compared to parallel flow. The heat transfer rate is nearly 20% increased in counterflow