Browsing by Author "Shrivastava, Sharad"

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Assessment of bone condition by acoustic emission technique: A review
(Scientific Research Publishing, 2009-03) Shrivastava, Sharad
The paper deals with the review of acoustic emission technique in biomedical field. The re- view is done with the aim to provide an ov erview of the use of AE technique in biomedical field, mainly co ncentrated on the AE beha vior o f bone under different loading conditions, its depend- ence on strain rate, in osteoporosis, monitoring the fracture healing process of bone. The over- all conclusion from the review was that almost all the studies in bone indicated that the initial AE occurs only in the plastic region and just prior to yield. That means the use of AE tech- nique for clinical application cannot be consid- ered as a safe technique, but the early occur- rence of AE events from callus promises the application of AE technique for monitoring the fracture healing process. The negligible effect of soft tissues on AE response of bone prom- ises AE to become a non-invasive method for assessment of bone condition
Assessment of bone condition using acoustic emission and acousto-ultrasonic technique
(BITS Pilani, 2010-12) Shrivastava, Sharad
CAD modeling and finite elemental design of indigenous knee brace
(Springer, 2019-01) Shrivastava, Sharad
Walking problems aggravate with the advent of old age. One of the treatments for the walking problems is the use of knee brace. This paper reviews the existing designs of knee braces, assesses their merits and demerits and proposes an efficient, cost-effective, light-weight and attractive design of knee brace for Indian population. This paper models design of knee brace and analyzes stress shielding capacity of the knee brace using Finite elemental analysis. This paper discusses how this knee brace can overcome difficulties faced by other knee braces in market.
A comprehensive review on mechanical performance and environmental resilience of fiber-reinforced polymer composites
(Taylor & Francis, 2026-03) Kumar, Rajesh; Shrivastava, Sharad
This review provides a comprehensive analysis of fiber-reinforced polymer composites (FRPCs), focusing on the enhancement of their mechanical properties and environmental resilience. This paper classifies key fiber types, such as glass, carbon, aramid, and basalt, and discusses their contributions to composite strength, stiffness, and durability. he paper highlights how manufacturing route and curing quality (e.g. hand lay-up, VARTM/RTM, pultrusion, prepreg/autoclave, and optimized compression molding) govern void content, fiber volume fraction, interlaminar consolidation, and interphase integrity, thereby strongly influencing tensile, flexural, interlaminar shear, fatigue, and impact responses. The critical role of the fiber-matrix interface is examined, with surface modification techniques and nanofillers, such as carbon nanotubes and graphene, highlighted for their impact on tensile, flexural, and shear properties. Environmental challenges, such as moisture absorption, chemical degradation, thermal aging, and UV exposure, are also addressed, with mitigation strategies such as surface coatings and modified resin systems. By integrating advanced interfacial engineering with environmental resilience techniques, this review outlines pathways for developing next-generation FRPCs for aerospace, automotive, marine, and civil infrastructure applications, while aligning with global sustainability goals.
Effect of electroless Ni plating on the properties of cold-sprayed Ni–Al2O3 coatings
(Emerald, 2017-06) Shrivastava, Sharad
This study investigated the effect of electroless nickel (Ni) plating (Np) on the properties of cold-sprayed nickel–alumina (Al2O3) coatings. To develop this two-layered coating system, nickel–alumina powder coating was first deposited by the cold spraying method on a mild steel substrate. Then, electroless Np was deposited on the as-sprayed nickel–alumina coating. The coating properties of the as-sprayed nickel–alumina coating and of the two-layered Np/nickel–alumina system were critically examined. The microstructural evolution was analysed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. In order to study possible changes in the mechanical properties of the system, Vickers microhardness experiments on the coatings and on the cross-sections were conducted. A possible improvement in the microhardness (14%) of the system was found after Np. Further, the corrosion behavior of the coating system was also studied critically. It was observed that the corrosion resistance of the Np/nickel–alumina coating system significantly improved and no corrosion effects and crack generation were observed at the substrate–coating interface
An evaluation of tactile frictional behavior of the wooden material
(IOP, 2019) Rathore, Jitendra S.; Shrivastava, Sharad
Skin tribology and contact mechanics have emerged as a recent topic of research, intended to unveil the behavior of human skin. There have been variegated efforts to calculate the coefficient of friction with respect to various parameters such as sliding speed, normal load, and surface roughness. Wood and other timber products have their importance considering the ergonomically designs that have gained importance nowadays. This article shows the relation between normal load, average sliding speed and coefficient of friction (μ) of various types of woods (Rosewood, Sunmica, Teak wood and Pine wood). An experimental investigation is conducted to understand frictional behavior between human skin and different types of woods. Wooden material has been tested with the normal load having the range of 6.5N to 13N. The variation of μ has been remarked as μrosewood>μpine>μteak>μsunmica. Experimental observation shows that the rosewood has the highest COF which suggests its application where grip and strength of high order are required.With decreasing sliding speed, the relation between normal load and μ become more significant.
Future research directions with Acoustic Emission and Acousto–Ultrasonic technique
(Inderscience, 2015) Shrivastava, Sharad
The paper deals with the existing research gap in medical field by the application of non-destructive testing technique. The paper gives an general idea about the various non-destructive testing techniques used in Biomedical field. It also covers the disadvantages of various techniques and how these disadvantages can be taken care by Acoustic emission and Acousto–ultrasonic technique. Based on literature review the gaps have been identified for the future research by these techniques. The assessment of bone condition can be effectively done by using acoustic emission and acousto–ultrasonic technique. Acousto–ultrasonic technique has already proved its usefulness in the assessing the composite materials. As bone is also a composite material, definitely this technique might give good results while assessing the bone condition.
High performance thermal-sprayed WC-10Co-4Cr coatings in narrow and complex areas
(Taylor & Francis, 2017-09) Shrivastava, Sharad
A complex geometry is always a challenge for the thermal spray community, because the spray angle affects the droplet’s impact on the substrate resulting in changes in coating properties. In this work, an attempt has been made to overcome this limitation. WC-Co-Cr coating was deposited on the CA6NM steel using newly developed high-velocity oxy liquid fuel (HVOLF) thermal spraying gun. As-sprayed coatings were analysed using x-ray diffraction, scanning electron microscopy for phase and microstructural analysis, respectively. Coating microhardness and porosity were also measured. Adhesion strength tests were conducted to determine the mechanical properties of the as-sprayed coatings. Results show that the coating produced by the HVOLF thermal spray system is excellent in terms of mechanical properties achieved. The angular design of this gun allows spraying in narrow areas, complex parts and inside internal diameter minimum as 140 mm having almost uniform coating properties at both spray angles (45° and 70°); this makes it a promising solution for coating deposition on complex geometries.
In vitro study of bone condition using acousto-ultrasonic technique
(Inder Science, 2011-04) Shrivastava, Sharad
This paper deals with the in vitro analysis of bones by acousto-ultrasonic technique. The comparison has been made between normal bones and fractured bones. The significant difference between the Stress Wave Factor (SWF) of the two suggests that this technique can be used for monitoring the fracture healing process and various other bone abnormalities. The good correlation between SWF and the failure strength of the dry bone (R = 0.99) also indicates that this technique can also be applied to predict the mechanical integrity of bone. The good correlation between SWF and depth of crack indicates that the technique can also be used to measure the severity of the crack.
Investigating the Effect of Cutting Parameters on Average Surface Roughness and Material Removal Rate during Turning of Metal Matrix Composite Using Response Surface Methodology
(IJRITCC, 2015) Shrivastava, Sharad
This research work investigate the effect of cutting parameters on average surface roughness and material removal rate during turning of Metal Matrix Composite using response surface methodology. The experimental studies are carried out under changing machining parameters like cutting speed, feed and depth of cut during turning of metal matrix composite. Response surface methodology based on the Face centered design technique has been used for the development of mathematical models to predict average surface roughness and metal removal rate. The conclusions revealed that the feed is the most influential machining parameter on the average surface roughness followed by depth of cut and the cutting speed. The depth of cut has significant for both the average surface roughness and metal removal rate for the MMC steel.
The Micro Structure and Tribological Properties of Liquid-Fuel HVOF Sprayed Fine Wc-Co-Cr Coating
(ASM International, 2015-05) Shrivastava, Sharad
This study compares high-velocity oxygen fuel spray MJP5000 and MJP 6000 (Patented by Metallizing Equipment Company Pvt Ltd.) using powder WC-Co- Cr. The microstructure and phase composition of powders and coatings will be analyzed by scanning electron microscopy and X-ray diffraction. Coatings were also characterized by their hardness, bond strength, roughness, deposition efficiency. Therefore, coating of high hardness and wear resistance can be produced with all HVOF spray system when the proper spray powder and process parameters are chosen. The results demonstrate that the powder exhibit various phase transformation during the spray process depending on type of powder, spray system and spray parameters.
Modification in Powder Feeder for Nano-Powder for Thermal Spray Thin Coatings
(ASM International, 2016-05) Shrivastava, Sharad
This paper discusses the modification of powder feeders to facilitate the deposition of nano materials by thermal spraying without the use of a suspension or solution precursor. Two powder feeder designs were developed and used to deposit nanocarbide coatings by HVOF spraying. The nano coatings were examined and tested, and the results are presented and discussed.
Moisture Absorption Behaviour of Biopolymer Polycapralactone (PCL) / Organo Modified Montmorillonite Clay (OMMT) biocomposite films
(IOP, 2018) Shrivastava, Sharad
Bio composite materials were fabricated using mixing biodegradable polymer polycaptalactone (PCL) and Organo Modified Montmorillonite Clay (OMMT) through solution casting. Various samples of bio composite films were prepared by varying the OMMT wt% composition by 0.1%, 0.5%, 1% and 1.5%. Thereafter, the density and water absorption of the composites were investigated with respect to immersion time in water. The moisture absorption results show that with an increase in weight percentage (from 0.1 to wt 1.5%) of OMMT within the bio polymer films, the absorption value of bio-nanocomposite films reduced rapidly from 34.4% to 22.3%. The density of hybrid composites also increased with increase in weight percentage of OMMT. The swelling characteristic of PCL increased with increasing % of OMMT clay. These results indicate that the optimized composition of constituents in composite membrane could effectively reduce the anhydrous conditions of bio-composite film
Monitoring of Fracture Healing Process by Acousto-Ultrasonic Technique Sharad Shrivastava1*
(Universiti Putra Malaysia Press, 2019) Shrivastava, Sharad
Presently the radiological examination is widely used for the assessment of in vivo bone condition. In some clinical problems such as diagnosis of the point of union of a fracture; the manual assessment is used along with radiological examination. Uncertainty regarding the significance of the radiographic and clinical findings may result in unnecessary long immobilization periods which can produce discomfort for the patient, as well as possible stiffness of the joints and sometimes permanent loss of mobility specially in older population. This paper deals with the in vivo analysis of bones by Acousto-Ultrasonic technique. The fracture was created through surgery on one of the limbs of rabbit and healing process was monitored through acousto-ultrasonic technique. A new index known as bone healing index was defined to calculate the end point of healing. In most of the cases, the bone healing index value was found to be 0.80, indicating that 80 % of the strength could only be restored at the completion of healing process.
Nonlinear vibration analysis of curvy single-walled boron nitride nanotube using mathematical modeling for dynamic responses
(World Scientific, 2023-08) Rathore, Jitendra S.; Shrivastava, Sharad
This work explores the feasibility of nonlinear behavior of doubly clamped single-walled boron nitride nanotube (SW-BNNT)-based nanoresonator. A nonlinear mathematical model of wavy SW-BNNT has been developed for analyzing the geometrical nonlinearity. Dynamic responses of nonlinear model have been analyzed for different waviness factors varying from 0.01 to 0.06 using various tools like time series, phase space, Poincaré map and Fast Fourier Transforms (FFTs). For the analysis, 20nm length of SW-BNNT has been considered. It has been observed from nonlinear analysis, that for responses with a lower value of waviness (e.g., 0.01) for 20nm long BNNT, the system’s nature loses its periodicity and shows onset of chaos with dense spectrum in Poincaré maps and irregular pattern in time response. Thus, it is concluded that chaotic response with a less strange attractor has been observed when waviness is 0.01. It is also concluded that, with increase in waviness factor from 0.02 to 0.06, the system showed the multi-periodic response with 2-T, 3-T and 4-T periods. The dynamic responses with varying waviness showed that the system behavior is changing from chaotic to periodic. This change in periodicity is one of the characteristics of chaotic solution.
Organically Modified Nanoclay and Aluminum Hydroxide Incorporated Bionanocomposites towards Enhancement of Physico-mechanical and Thermal Properties of Lignocellulosic Structural Reinforcement
(Springer, 2018-02) Shrivastava, Sharad
A range of bio-nanocomposites were prepared by incorporation of organo modified montmorillonite nanoclay (OMMT) with or without use of aluminum hydroxide (Al(OH)3) within polylactic acid (PLA) solution. Furthermore, the solution was employed for modification of ligno-cellulosic (jute) fabric structural reinforcements. The successful incorporation of nanofillers within the host polymer, polylactic acid (PLA) was confirmed by Fourier-transform infrared spectroscopy (FT-IR). Water uptake and swelling behaviour studies revealed that the water uptake and swelling ratio of bio-composites reduced significantly as compared to pristine jute fabric, whereas upon incorporation of OMMT and Al(OH)3, the water barrier properties reduced even further in the developed bio-nanocomposites. The flexural strength of the bio-nanocomposites also showed improved mechanical and dimensional stability. Synergistic effects of OMMT and Al(OH)3 were observed in enhancing the aforementioned physico-mechanical properties. Scanning electron microscopy (SEM) studies revealed microstructural details of developed samples. Similarly, the thermo-gravimetric analysis and linear burning rate studies of Al(OH)3 treated bio-nanocomposite materials revealed enhanced thermal resistance and reduced flammability respectively compared to both pristine woven jute fabric and fabrics treated with PLA alone or those without Al(OH)3. From the above results it can safely be said that the bio-nanocomposite material can be a prospective candidate for development of flame retardant biopackaging.
A review on mechanical behavior of natural fiber based hybrid composites
(Sage, 2012-06) Jalan, Arun Kumar; Shrivastava, Sharad
Hybrid composites are manufactured by combining two or more fibers in a single matrix. Hybrid composites can be made from artificial fibers, natural fibers and with a combination of both artificial and natural fibers. Hybrid composites can help us to achieve a better combination of properties than fiber reinforced composites. The constituent fibers in a hybrid composite can be altered in a number of ways leading to variation in its properties. The importance of this review can be attributed to the significant aspects of natural fiber based hybrid composites which are found to be predominantly affected by factors which include variation in fiber volume/weight fraction, variation in stacking sequence of fiber layers, fiber treatment and environmental conditions.
Study of fracture toughness and bend test morphologies of HVOF sprayed Cr3C2-25% NiCr coating after heat treatment
(IOP, 2017) Shrivastava, Sharad
Majority of the industrial components are subjected to high temperature exposure, where crack propagation occurs due to shear failure. The paper involves the study of the fracture toughness of heat treated Cr3C2-NiCr coating at three different service temperatures (750°C, 850°C, and 950°C for 1-hour aging) using indentation techniques to measure the crack resistance of the coating. At 750°C and 850°C, the coating cracked at the bend area, but not spalled. At 950°C, the coating spalled and delaminated from the substrate indicating poor adhesion after prolonged exposure. The influence of heat treatment on the fracture toughness and adhesion properties of the Cr3C2-25%NiCr coating were also investigated. The high temperature exposure at 950°C, resulted in a shear failure of the coating due to the presence of splat contraction. The increase in temperature increases the fracture toughness KIC of the coating, with the decrease in hardness. It was observed that the oxidation levels enhanced on the top layer of the coating, which acted like a core region for crack initiation at 950°C resulting in shear failure during bend test.
Synthesis and characterization of fire resistance polymeric coating solution for carbon-blended aluminized (E-glass-based) and non-aluminized fabric
(Taylor & Francis, 2019-05) Shrivastava, Sharad
In this study, we report the development and characterization of fire-resistant non-intumescent polymeric resin for aluminized (E-glass-based) and non-aluminized (basofil/nomex/carbon-based) firefighting suit fabrics. The prospective coating resin is synthesized via two-step polymerization of polyimide using dimethylacetamide (DMAc) as a common solvent. 3-Aminopropyltriethoxysilane (APTES) is used as a coupling agent and is added just before coating. All the coating samples are prepared by hand layup technique and are allowed to cure (known as imidization) under the oven with increasing the temperature step-by-step from 80 to 350 °C. The imidization of coating resin is confirmed by FT-IR spectra analysis. Furthermore, all the samples are characterized with flammability, adhesion, thermal protective index, heat char and ignition, and thermal shrinkage as per BS 3120, MIL-C-29143, BS 3791, D-5537, and NFPA 1976 standards, respectively. The observed results confirmed that the prospective resin could be a better choice as fire-resistant coating for carbon-blended aluminized and/ non-aluminized fabric.
Thermoatomic analysis of monovacancy defected single-walled boron nitride nanotube under quasi-static strain: Insights from molecular dynamics
(Elsevier, 2023-01) Rathore, Jitendra S.; Belgamwar, Sachin U.; Rao, Venkatesh K.P.; Shrivastava, Sharad
The structural and thermal stability of single-walled boron nitride nanotubes (SWBNNTs) under strained conditions are essential in pursuit of their applications that are subjected to high temperature processing and/or working environment. However, there are dearth of high temperature (>1000 K) studies on SWBNNTs and other forms of hexagonal boron nitride (h-BN) structures, either with or without defects, due to experimental difficulties. In this paper, an atomistic approach is adopted to perform uniaxial tensile and torsional quasi-static straining of pristine and monovacancy defected SWBNNTs at different temperatures while the thermal stability of monovacancy defected SWBNNT structures were predicted from its mean square displacement during equilibration up to 2400 K temperature. During uniaxial tensile and torsional straining, Young's modulus, Poisson's ratio, and shear modulus values of monovacancy defected SWBNNTs decreases on increasing the temperature condition compared to high temperature. For instance, in case of monovacancy concentration of 0.2% in SWBNNTs, the increase in temperature from 300 K to 2400 K reduced its Young's, Poisson's ratio, axial strain and shear moduli by 14%, 19%, 50.5%, and 87.28%, respectively. Findings of this work may have future implication in extreme temperature applications of BNNT-based structural materials.