•Fabrication, modeling and application of phase change materials for battery thermal management system.•Thermal management of the battery systems in an electric vehicles.•Future challenges and ...opportunities concerning the PCM application and further research on novel materials for BTMS in an electric and hybrid vehicles.
Battery is essential parts of an electric and hybrid electric vehicle. Good amount of heat is generated by charging and discharging actions. For maximum efficiency, reliability of utmost necessary to conserve the optimum temperature by employing a proper battery thermal management system. Uses of Phase Change Materials for thermal management have attracted attention in recent years due to its lightweight, improved energy efficiency, less intricacy and better thermal homogeneity. These materials are a potential substitute for economical, and simple operation. Phase Change Materials could be utilized as active or passive systems, empowering the universal system to nurture near-autonomous performances. This work consists of the discussions on battery thermal management systems using phase change materials, enhancement of Phase Change Materials’ thermal conductivity, thermal management schemes and finally concluding with the application sections. Heat transfer can be augmented by application of Phase Change Materials through thermally conductive particles, metal fin, metal foam and expanded graphite matrix. Newly developed thermal management configurations like multi-layer Phase Change Materials and sandwiches are also outlined. Additionally, a thermal management system merging Phase Change Material cooling via air or liquid is also presented.
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Titanium is a most common and best biocompatible material. The demand and application of Ti alloy is increasing rapidly in orthopedics for clinical operations. The porous structures have been ...designed for bone tissue engineering or orthopedic applications due to its moderate Young's modulus, excellent compressive strength, biocompatibility and sufficient space for cell accommodation. The porous scaffolds with individual complex internal and external shape can be manufactured by additive manufacturing (AM) processes especially selective laser melting (SLM), both of these have great importance for repairing of large sectional bone defects. This advantage makes the SLM process one of the most competitive AM processes used in the biomedical fields. Seven different Ti–6Al–4V porous scaffolds (Diamond, Grid, Cross, Vinties, Tesseract, Star and Octet) of 15 mm cube with 65% porosity were designed using Rhino 6 software and fabricated through SLM using Ti–6Al–4V powders. This work mainly focused on porous scaffolds design and manufacturing by AM particularly SLM, can able to produce scaffolds of nanoscale grains because of its higher heating rate and lower holding time. But this process generally results insufficient compaction where desired function is not achieved. The scaffolds manufactured by SLM have relatively high accuracy of pore structure and low mechanical strength. Grid type structure exhibits lower surface roughness value and better manufacturing ability where error percentage of porosity is lower than the other scaffolds.
The process parameters employed in the study like laser power, scanning speed, hatch distancing and layer thickness are the most significant factors that influence the defect behaviour and morphology of the SLM-fabricated samples. Porosity percentage and surface roughness of the scaffold palys a vital role on its desired functions. While the porosity percentage are also effected by input process parameters resulting the variation on effective elastic modulus. The increase in scanning speed leads to elevation of the cooling rate, which results in a finer microstructure. On the other hand, with lower scanning speeds, coarse microstructure is observed.
Time dependent low-velocity single and multiple impact response of functionally graded (FG) untwisted and pretwisted conical shells are analysed considering porosity factor. A modified Hertzian ...contact law which accounts for permanent indentation is considered for the low velocity impact problem. An eight-noded isoparametric shell element is used for the finite element formulation while Newmark’s time integration algorithm is used to solve the time dependent equations. The effects of porosity considering even and uneven porosity factor, initial velocity of impactor (
VOI
), mass of the impactor and twist angle of FG conical shell on the transient impact response of the conical shell are examined and analyzed. The contact force and indentation increase with increase of
VOI
and mass of the impactor while the contact duration decreases for both the occasions. Twist angle has a significant effect on contact force but has marginal effect on contact duration. Contact force for perfect (porosity free) FG conical shells is higher than that of porous FG conical shells. Lower contact force is observed for higher porosity factor. Even porous FG conical shell predicts lower contact force and higher shell displacement than that of an uneven porous FG conical for a given porosity factor.
In a nuclear power plant, thermal striping occurs at the T-junction, where high-temperature steam and low-temperature processed fluids mix. The non-uniform temperature distribution and temperature ...fluctuation in the pipe produced by thermal striping may lead to cracks and high cycle thermal fatigue failure. The use of a thermal sleeve can prevent this issue to a certain extent, but delamination is a major concern in such thermal striping. Functionally graded materials (FGMs) in which the material properties are graded along the thickness direction can relieve the thermal stress gradient in the pipe, eliminating the delamination problem. In this study, a one-way fluid structure interaction simulation of ceramic and structural steel functionally graded T pipes under thermal striping was performed using the detached eddy simulation method. The initial condition of velocity and temperature was used based on the “WATLON” experiment conducted by the Japan Atomic Energy Agency. Spectral analysis was performed to evaluate the temperature fields for both the fluid and the pipe, as well as to determine the temperature fluctuation characteristic. The temperature variation in the pipe was then used in the transient structural analysis to evaluate fluctuations in the thermal stress. Finally, the rainflow counting method was employed to determine the stress cycles of the pipe. The thermal stress cycles of homogenous, composite, and FGM pipes were compared. The reduced amplitude of the stress cycle of the FGM pipe confirms a higher fatigue life and potential application of the FGM at the T-junction.
Laser ablation of solid aims that liquid media could comprehend for synthesizing nanostructures having numerous morphologies and compositions, namely nanocubes, nanoparticles, nanorods, etc. ...Simultaneously, post-laser irradiation of suspended nanomaterials could be employed for additional modification of their dimension, geometry, and configuration. On comparison with various classical chemical process, laser ablation in liquid (LAL) is an easy and “clean” methodology which usually functions in water or any organic liquid in ambient environments. LAL is intricately established for preparing a sequence of nanomaterials having distinct microstructures as well as phases, also attaining one-step creation in numerous functional nanostructures toward the quest for new characteristics and employment in optics, detection and biotic areas. Development tools in addition to artificial approaches grounded on this approach are methodically examined; also, the described nanostructures resulting in exceptional properties of LAL were reviewed along with the study of their applications.
Staphylococcus aureus is opportunistic human as well as animal pathogen that causes a variety of diseases. A total of 100 Staphylococcus aureus isolates were obtained from clinical samples derived ...from hospitalized patients. The presumptive Staphylococcus aureus clinical isolates were identified phenotypically by different biochemical tests. Molecular identification was done by PCR using species specific 16S rRNA primer pairs and finally 100 isolates were found to be positive as Staphylococcus aureus. Screened isolates were further analyzed by several microbiological diagnostics tests including gelatin hydrolysis, protease, and lipase tests. It was found that 78%, 81%, and 51% isolates were positive for gelatin hydrolysis, protease, and lipase activities, respectively. Antibiogram analysis of isolated Staphylococcus aureus strains with respect to different antimicrobial agents revealed resistance pattern ranging from 57 to 96%. Our study also shows 70% strains to be MRSA, 54.3% as VRSA, and 54.3% as both MRSA and VRSA. All the identified isolates were subjected to detection of mecA, nuc, and hlb genes and 70%, 84%, and 40% were found to harbour mecA, nuc, and hlb genes, respectively. The current investigation is highly important and informative for the high level multidrug resistant Staphylococcus aureus infections inclusive also of methicillin and vancomycin.
This article deals with effect of rotation and pretwist angle on free vibration characteristics of functionally graded conical shells. The dynamic equilibrium equation is derived from Lagrange’s ...equation neglecting the Coriolis effect for moderate rotational speeds. The materials properties of conical shell are varied with a power-law distribution of the volume fractions of their constituents through its thickness. Convergence studies are performed in respect of mesh sizes, and comparisons of the present solutions and those reported in open literature are provided to substantiate the accuracy of the proposed method. Computer codes developed to obtain the numerical results for the combined effects of twist angle and rotational speed on the natural frequencies of functionally graded conical shells. The mode shapes for a typical laminate configuration under different conditions are also illustrated. Numerical results are obtained for the non-dimensional fundamental (NDFF) and second frequencies (NDSF).
A finite element-based method for determining the first-ply failure (FPF) strengths of delaminated composite pre-twisted shallow rotating conical shells subjected to a central point load is presented ...in this work. The influence of transverse shear deformation and rotary inertia are accounted for in the eight-noded shell element employed in the present analysis based on Mindlin's theory. The delamination of the crack front is modeled using the multi-point constraint algorithm, while the initial stresses arising out of rotation are determined iteratively. The present study uses the maximum strain, maximum stress, Hoffman, Tsai–Hill, and Tsai–Wu failure criteria to arrive at the FPF loads. The results illustrate the effect of some vital parameters like stacking sequence, pre-twist angle, aspect ratio, presence and location of delamination, and rotational speed on the FPF in the delaminated composite conical shell with an initial twist. The spatial distributions of the stresses in the material directions and deflections identify the first-ply failure zones at the failure loads obtained. It is found that the FPF strengths increase on increasing the aspect ratio and non-dimensional rotational speed whereas the strength decreases with size and number of delaminations. The stresses developed at the FPF loads are lower in non-rotating conical shells compared to rotating shells.
Millimeter-sized objects like engine components, sand particles, or debris impact on the gas turbine blades very frequently during operation of a gas turbine. This is one of the major concerns in the ...aviation industry, and various studies and research have been done throughout the decades in preventing the damage. Such impacts may not affect or damage the gas turbine blades but the frequent impact leads to the fatigue of the gas turbine blades and eventually to failure. The low-velocity impact analysis of gas turbine rotor blades in aviation has been presented in this study. Impact analysis of spherical steel balls as impactors of different masses on titanium-alloyed rotor blades is recorded and the result data are collected. To verify the present method, the numerical data are also compared to open literature. The analysis has been done using ANSYS software considering factors like meshing sizes, impactor size, and velocity.
Bone implants are extensively used in biomedical science for replacement of bone and joint defects, but a variation of stiffness between implant material and bone causes load redistribution around ...the implant, resulting in autogenous bone fracture or loosening of implant, called stress shielding. To overcome this problem, porous biocompatible titanium alloy (Ti-6Al-4V) is used to reduce the stiffness of metallic implants equivalent to bone stiffness. Ti-6Al-4V is considered to fabricate porous implant scaffold due to its excellent mechanical properties, biocompatible nature, higher corrosion resistance, and high strength-to-weight ratio. Four different porous scaffolds, namely diamond, grid, cross, and vinties, are modeled using Rhino 6 software, where 65% theoretical porosity is maintained. Additive manufacturing (AM) technique, mainly selective laser melting (SLM), is used to fabricate these porous scaffolds. Actual porosity and surface roughness of the fabricated samples are measured. Compression tests of each porous scaffold are performed in INSTRON compressive testing machine. Elastic modulus of fabricated samples shows excellent matching with a human bone, while compressive strength shows superior value compared to the human bone which will help to reduce the stress shielding effect and also will increase the longevity of the implants. The relative elastic modulus (modulus ratio of porous scaffold to solid cube) of the samples is studied using the Gibson–Ashby correlation model. The porous scaffolds made with Ti-6Al-4V have low effective Young’s modulus, excellent compressive strength, and sufficient cell accommodation space to fulfill medical requirements for clinical demands.
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