Prakash Kumar
@bitmesra.ac.in
Assistant Professor, Department Production Engineering
BIT Mesra
RESEARCH INTERESTS
Vibration and control
Nonlinear dynamics
Structural dynamics
Modelling of human-induced force
Casting and Welding.
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Sanjay Kumar, Prakash Kumar, and Sai Vijay Kumar
Springer Science and Business Media LLC
Niraj Kumar, Prakash Kumar, Rajat Upadhyaya, Sanjeev Kumar, and Chandan Panday
MDPI AG
For high-temperature industries operating at nearly 750 °C (advanced ultra-super critical boilers), dissimilar welding between Inconel alloys and austenitic stainless steel (ASS) are commonly adopted. The high-temperature resistive properties of Inconel and ASS alloys are highly qualified for high-temperature applications. In this experimental study, dissimilar autogenous laser beam welding (LBW) between Inconel 718 and ASS 304L is investigated. This paper explains the detailed study on the microstructural and mechanical behavior of the LBW dissimilar joint. The microstructural study indicates the presence of laves phases in the weld zone. Additionally, the weld zone shows heterogeneous microstructural formation, owing to the non-uniform welding heat in the different areas of the weld zone. The optical images show the presence of mixed dendrites, i.e., equiaxed, cellular, and columnar morphology, in the weld zone and in the fusion zones of either side. The energy-dispersive spectroscopy (EDS) results show the presence of segregated elements (Nb, Mo, Cr, and Ti) at the weld center. These segregated elements are the reason for the occurrence of the laves phases in the weld zone. The presence of Nb and Mo may form the laves phase (Fe, Ni, Cr)2 (Nb, Mo, Ti) along with Fe, Ni and Cr. The presence of an unmixed zone is observed in the HAZ of the Inconel 718, whereas the HAZ of the ASS 304L shows the presence of an unmixed zone (UZ) and a partially mixed zone (PMZ), as observed on the optical and SEM images. To obtain the mechanical properties of the laser weld, the tensile test, microhardness test, and impact test were measured at room temperature. The tensile specimens show a brittle failure at the ASS 304L side, which was initiated from the weld top, with average tensile stress of 658.225 MPa. The reason for the ASS 304L fracture is because of the presence of UZ and PMZ, and the lower hardness value of the ASS side. The UZ and PMZ lead to the fracture of the tensile specimen along the ASS 304L side’s HAZ. The measurement of microhardness carried out along the transverse length indicates an average microhardness of 214.4 HV, and the value is 202.9 HV along the weld depth. The mixed morphology of the microstructure promotes the variation in hardness in both directions. The hardness along the length shows a high hardness value in the weld zone and uniformly decreases along the base materials. The Charpy impact test of the weld zone shows the brittle fracture of the impact specimens. From the microstructural and mechanical results, the LBW dissimilar weld between Inconel 718 and ASS 304L is qualified for safe use in high-temperature end applications, such as AUSC power plants.
Niraj Kumar, Chandan Pandey, and Prakash Kumar
ASME International
Abstract In this review paper, dissimilar welding between Inconel and austenitic stainless steel along with its application has been outlined for high-temperature applications. The mechanical and microstructural behavior of this dissimilar joint has been summarized thoroughly in this article. Dissimilar welding of Inconel alloys and stainless steel (SS) has massive demand in high temperature and high corrosive applications industries. Austenitic stainless steel contains 16–26% of Cr and 6–12% of Ni elements showing FCC structures have good weldability and high corrosion resistance. Austenitic stainless steel such as 304, 316 L, 304H, etc., containing austenite microstructure used in high-temperature applications like power plants, heat exchangers, heating elements, aircraft, and others. In addition, Ni-based Inconel alloys show high-temperature strength and corrosion resistance and are frequently used in high-temperature applications. Ni-based Inconel 718 alloy possesses excellent strength, corrosion resistance and creep resistance at high temperatures are frequently used in combustion chambers, power plants, and turbine blades applications. Inconel alloyed by elements Ti, Al and Nb attain strength by forming phases such as ɣ/-Ni3(-Ti, Al), ɣ//-Ni3Nb, and carbides such as MC and M23C6, nitrides, laves phase. The GTA dissimilar welding between expensive Inconel and cheaper stainless steel is successfully used in nuclear power plants. The dissimilarity in melting point, chemical composition, thermal, mechanical, and other properties between these materials make welding challengeable. This review paper focused on problems related to dissimilar welding like forming unmixed zone, elemental segregation, formation of laves phase, sensitization, microfissuring, and solidification cracking.
Surendra Rajit Prasad, Prakash Kumar, Saptarshi Mandal, Anu Mohan, Radhika Chaurasia, Ashish Shrivastava, Pallaprolu Nikhil, Dande Aishwarya, P. Ramalingam, Rahul Gajbhiye,et al.
Springer Science and Business Media LLC
AbstractWe evaluated the anti-leishmanial efficacy of different saturated medium-chain fatty acids (FAs, C8–C18) where FA containing C8 chain, caprylic acid (CA), was found to be most potent against Leishmania donovani, the causative agent for visceral leishmaniasis (VL). Different analogs of CA with C8 linear chain, but not higher, along with a carboxyl/ester group showed a similar anti-leishmanial effect. Ergosterol depletion was the major cause of CA-mediated cell death. Molecular docking and molecular dynamic simulation studies indicated the enzyme mevalonate kinase (MevK) of the ergosterol biosynthesis pathway as a possible target of CA. Enzyme assays with purified recombinant MevK and CA/CA analogs confirmed the target with a competitive inhibition pattern. Using biochemical and biophysical studies; strong binding interaction between MevK and CA/CA analogs was established. Further, using parasites with overexpressed MevK and proteomics studies of CA-treated parasites the direct role of MevK as the target was validated. We established the mechanism of the antileishmanial effect of CA, a natural product, against VL where toxicity and drug resistance with current chemotherapeutics demand an alternative. This is the first report on the identification of an enzymatic target with kinetic parameters and mechanistic insights against any organism for a natural medium-chain FA.
Amit Kumar Dubey, Prakash Kumar, Debabrata Mandal, V. Ravichandiran, and Shubhankar Kumar Singh
Springer Science and Business Media LLC
Prakash Kumar, Pawan Kumar, Debabrata Mandal, and Ravichandiran Velayutham
Frontiers Media SA
Before the discovery of the proteasome complex, the lysosomes with acidic proteases and caspases in apoptotic pathways were thought to be the only pathways for the degradation of damaged, unfolded, and aged proteins. However, the discovery of 26S and 20S proteasome complexes in eukaryotes and microbes, respectively, established that the degradation of most proteins is a highly regulated ATP-dependent pathway that is significantly conserved across each domain of life. The proteasome is part of the ubiquitin-proteasome system (UPS), where the covalent tagging of a small molecule called ubiquitin (Ub) on the proteins marks its proteasomal degradation. The type and chain length of ubiquitination further determine whether a protein is designated for further roles in multi-cellular processes like DNA repair, trafficking, signal transduction, etc., or whether it will be degraded by the proteasome to recycle the peptides and amino acids. Deubiquitination, on the contrary, is the removal of ubiquitin from its substrate molecule or the conversion of polyubiquitin chains into monoubiquitin as a precursor to ubiquitin. Therefore, deubiquitylating enzymes (DUBs) can maintain the dynamic state of cellular ubiquitination by releasing conjugated ubiquitin from proteins and controlling many cellular pathways that are essential for their survival. Many DUBs are well characterized in the human system with potential drug targets in different cancers. Although, proteasome complex and UPS of parasites, like plasmodium and leishmania, were recently coined as multi-stage drug targets the role of DUBs is completely unexplored even though structural domains and functions of many of these parasite DUBs are conserved having high similarity even with its eukaryotic counterpart. This review summarizes the identification & characterization of different parasite DUBs based on in silico and a few functional studies among different phylogenetic classes of parasites including Metazoan (Schistosoma, Trichinella), Apicomplexan protozoans (Plasmodium, Toxoplasma, Eimeria, Cryptosporidium), Kinetoplastidie (Leishmania, Trypanosoma) and Microsporidia (Nosema). The identification of different homologs of parasite DUBs with structurally similar domains with eukaryotes, and the role of these DUBs alone or in combination with the 20S proteosome complex in regulating the parasite survival/death is further elaborated. We propose that small molecules/inhibitors of human DUBs can be potential antiparasitic agents due to their significant structural conservation.
S. Sirohi, A. Sauraw, A. Kumar, S. Kumar, T. Rajasekaran, P. Kumar, R. S. Vidyarthy, N. Kumar, and C. Pandey
Springer Science and Business Media LLC
Chinmay Haldar, Prakash Kumar, Om Prakash Pandey, Kalachand Sain, and Santosh Kumar
Elsevier BV
Vishnu Kant, Pawan kumar, Ravi Ranjan, Prakash Kumar, Debabrata Mandal, and Saravanan Vijayakumar
Springer Science and Business Media LLC
C. Pandey, Naveen Kumar, S. Sirohi, T. Rajasekaran, S. Kumar, and P. Kumar
Springer Science and Business Media LLC
C. Pandey, Naveen Kumar, S. Sirohi, T. Rajasekaran, S. Kumar, and P. Kumar
Springer Science and Business Media LLC
Pragya Prasanna, Prakash Kumar, Saurabh Kumar, Vinod Kumar Rajana, Vishnu Kant, Surendra Rajit Prasad, Utpal Mohan, V. Ravichandiran, and Debabrata Mandal
Elsevier BV
C. Pandey, J.G. Thakare, P.K. Taraphdar, P. Kumar, A. Gupta, and S. Sirohi
Elsevier BV
Abstract The dissimilar welds joint of 2.25Cr-1Mo steel and lean duplex LDX2101 steel was prepared using the Gas Tungsten Arc Welding (GTAW) process and employing the Inconel 617 filler. The microstructural stability of the dissimilar welds joint (DWJ) was studied using the optical microscope and field emission scanning electron microscope (FESEM) for as-welded (AW) and post-weld heat treatment (PWHT) condition. The PWHT was employed at 760 °C (PW 1) and 810 °C (PW 2) for 2 h of duration. The application of the heat-treatment resulted in the formation of the soft zone at the interface of weld metal and HAZ in 2.25 Cr-1Mo side, i.e., low Cr side. The mechanical behavior of the DWJs was also studied for AW and PWHT condition. A measurable change in the width and hardness of the soft and hard zones was measured with an increase in PWHT temperature. For weld metal, the minimum average hardness was measured 237 HV in AW and a maximum of 248 HV for PW 2. In the AW condition, the average CIT of the weld metal was measured 46.5 ± 3.5 J, which meets the minimum recommended value as per EN 1557:1999 standards. The PWHT showed a drastic reduction in CIT and a minimum of 34 ± 3 J was measured for PW 2. The CIT of the 2.25Cr-1Mo HAZ (notch adjacent to fusion boundary includes the soft ferrite region) was measured 45 ± 5 J in AW and get increased drastically after the PWHT and maximum was measured for PW 2 (86 ± 5 J).
S. Sirohi, P. Kumar, A. Gupta, S. Kumar and C. Pandey
Nitish Kaushik, Prakash Kumar, Joyjeet Ghose, and Sanjay K Jha
Elsevier BV
Abstract Aluminium hybrid metal matrix nano composite (AHMNC) material has all the advantages of conventional metal matrix nano composite with multifunctional properties because of the hybrid reinforcement. As a result, these materials offer a unique combination of properties that are not possible to achieve in conventional materials. The present study deals with the fabrication of aluminium hybrid nano composites by reinforcing Al2014 with nano sized B4C and graphite, processed through stir casting route followed by ultrasonic and squeeze casting. The addition of B4C improves the hardness, whereas Gr particles improve wear resistance in the composite. These combinations of the reinforcements are chosen for application under high abrasive conditions. Ultrasonic agitation has been done to uniformly distribute the reinforcement, whereas squeeze casting is done to reduce the porosity of the cast. The cast composite has been cut to prepare specimens for hardness, tensile strength, and microstructure as per the ASTM standards. The mechanical properties of the composite were evaluated and compared to the conventional. The microstructure of the composites was studied using optical microscopy to investigate the proper distribution of reinforcement and microstructure in the AHMNCs. The result indicates a significant improvement in the hardness. Further, the microstructure studies reveal that the reinforcement was fairly uniformly distributed over the matrix material.
Prakash Kumar, Shailesh Dewangan, and Chandan Pandey
Elsevier BV
Prakash Kumar, Anil Kumar, Chandan Pandey, Shailesh Dewangan, and Sanjay K. Jha
Elsevier BV
Abstract A Nonlinear Energy Sink (NES) having essential nonlinear stiffness, it is nonlinearly attached to a primary system. In contrast to Tuned Mass Damper, the NES could be capable over a wider frequency range and only require a small additional mass. NES have good potential for vibration mitigation and energy harvesting. One of the most common energy sources in an environment is ambient vibration. Some micro electro-mechanical system with magnetostrictive or piezoelectric materials is used to convert ambient vibration into electrical energy. That can be stored and used to power other devices such as wireless sensors, health monitoring sensors or replacing small batteries that have a finite lifespan or would require difficult and expensive maintenance. This study focuses on materials for energy harvesting with NES. Piezoelectric materials have a good capability to convert the mechanical vibration energy into electrical energy and vice versa; therefore, they are more suitable for energy harvesting with NES. A state of the art review of the piezoelectric material frequently used in NES coupled energy harvester with their relative merit is presented.
Chandan Pandey, M.M. Mahapatra, Pradeep Kumar, Prakash Kumar, N. Saini, J.G. Thakare, and S. Kumar
Elsevier BV
Prakash Kumar, Anoop Kumar Godara, and Anil Kumar
Springer Singapore
Shailesh Kumar Dewangan, Prakash Kumar, and Sanjay Kumar Jha
Springer Singapore
Chandan Pandey, M. M. Mahapatra, Pradeep Kumar, N. Saini, J. G. Thakre, and Prakash Kumar
ASTM International
Prakash Kumar, Anil Kumar, and Vitomir Racic
World Scientific Pub Co Pte Lt
The paper proposes a self-sustained single-degree-of-freedom oscillator to accurately generate the longitudinal contact force between a pedestrian’s feet and the supporting flat rigid surface. The model is motivated from the self-sustained nature of pedestrian walking, i.e. a pedestrian produces the required internal energy to maintain a repetitive body motion. It is derived by adding two nonlinear terms to the conventional Rayleigh oscillator to yield odd as well as even harmonics, as observed in experimentally recorded longitudinal force data. For the dynamic analysis of the oscillator, two methods are adopted: the energy balance method and the Lindstedt–Poincare perturbation technique. Moreover, the least-squares identification procedure is used to identify values of the oscillator parameters from the force records of 12 different pedestrians walking on an instrumented treadmill at 10 walking speeds. The results generated by the proposed oscillator agree well with the experimental data.
Prakash Kumar, Anil Kumar, and Silvano Erlicher
World Scientific Pub Co Pte Lt
This study proposes a single degree of freedom nonlinear oscillator to model the lateral movement of the body center of mass of a pedestrian walking on a flat rigid surface. Experimentally recorded ground reaction force of a dozen of pedestrians in the lateral direction is used to develop the model. In detail, the hardening and softening effects are observed in the stiffness curve as well as higher odd harmonics are present in the frequency spectrum of the lateral force signals. The proposed oscillator is a modification of the Rayleigh and the Van der Pol oscillators with additional nonlinear softening and hardening terms. To obtain an approximation of the limit cycle of the oscillator and its stability, two methods are studied: the energy balance method and the Lindstedt–Poincare perturbation technique. The experimental force signals of pedestrians at four different walking speeds are used for the identification of the values of the model parameters. The results obtained from the proposed model show a good agreement with the experimental ones.
Prakash Kumar, Anil Kumar, Vitomir Racic, and Silvano Erlicher
Elsevier BV