On the Prediction of Grain Refinement Mechanism in Direct Chill Casting of Aluminum and Its Alloys Under Low Degree Mechanical Forced Convection

Deepak Patel,Prasenjit Biswas,Anil Kumar,Hiren R. Kotadia,Archana Mallik,Sanjeev Das 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The present investigation focuses on grain refinement in pure aluminum and its alloy under mechanical stirring with a verylow degree of forced convection of 800 rpm as compared to reported values of up to 8000 rpm during direct chill castingprocess (DC). Commercially pure aluminum (99.7%) and Al6082 alloy billets were fabricated in an in-house designed DCcasting simulator. Mechanical forced convection (MFC) was applied to the melt during casting by a common four-bladedimpeller. The microstructural properties of the as-cast billets have been analysed to study the effect of MFC during casting andsolidification. The structure of both Al and its alloy is found to be refined in presence of MFC as compared to conventionalDC. A combination of simulation, experimental and theoretical approaches has been used to determine the effect of MFCin melt-temperature distribution to propose the mechanism of grain refinement. It has been observed that MFC prominentlyreduces the temperature gradient and extends undercooling time, resulting in fine grain structure.

C2 Superior Facetal Osteotomy: A Novel Technique in Complex Craniovertebral Junction Surgery for C1 Lateral Mass Screw Placement

Deepak Kumar Singh,Shankar Diwakar,Vipin Kumar Chand,Singh Rakesh Kumar,Singh Neha 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.6

Complex craniovertebral junction (CVJ) defects account for a considerable proportion of CVJ diseases. Given the heavily assimilated C1, an unfavorable C1–C2 joint orientation, an overriding C2 superior facet, a low-hanging occiput, and an abnormal vertebral artery course with a high-riding vertebral artery, placement of C1 lateral mass screws might be difficult. To address this, a novel technique for placing C1 lateral mass screws that avoid vertebral artery injury, low-hanging occiput, and overriding C2 superior facet was developed in this study. This approach enables firm fixation of C1–C2 even in difficult situations where the placement of the C1 lateral mass is challenging.

Green and proficient process for industrial-scale preparation of Gymnema sylvestre standardized-extract enriched with Gymnemic acids through polymer-matrix-adsorption to reduce hyperglycemia

Deepak Kumar,Vipin Kumar Singh,Narayan Prasad Yadav,Sudeep Tandon,Karuna Shanker,Chandan Singh Chanotiya,Narendra Kumar,Puja Khare,Anirban Pal,Debabrata Chanda,Dharmendra Saikia,Yusuf Hussain,Abha Mee 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-

Gymnema sylvestre is an important medicinal plant, but a method for preparing standardized extractenriched with biomarkers is not available. The practiced crude hydro-alcoholic extracts of G. sylvestrecontained a few percentage of gymnemic acids (GAs). The enrichment of GAs in preprared extracts isessential from a pharmacology point of view. Presently, a scale-up process has been developed forpreparing G. sylvestre standardized extract (Gym-EEXT). Crude extract (Gym-Crude) was prepared in10-kg batches to obtain a yield of 268.1 mg/g, but GAs was merely 9 mg/g (GA-IV 6.7 mg/g, and GAXVII2.3 mg/g) in 30 % ethanol–water solvent at 50 C in 5 h. Further, Gym-Crude was processed throughpolymer-matrix-adsorption techniques for getting Gym-EEXT (150.9 mg/g) with improved percentage ofGAs (>10 %) comprised of deacylgymnemic acid (DGA: 8.9 mg/g), gymnemagenin (2.3 mg/g), GA-IV(78.6 mg/g), and GA-XVII (10.2 mg/g). For safety aspects, the pesticide residues, solvent residues, heavymetal, aflatoxins, and mutagenicity in Gym-EEXT were below the detection limits. Hence, Gym-EEXT wasenriched with GAs, and fully safe with compliance according to USP-561. An insignificant effect of Gym-EEXT on vitals of experimental mice was observed in acute and sub-acute oral-toxicityexperiments. Gym-EEXT significantly improved the blood glucose metabolism, and hence, it potentiallyreduces hyperglycaemia. Unique chromatographic protocols were developed for the isolation of biomarkerson a 1-kg scale from Gym-Crude with yield of gymnemagenin (5.5 %), and DGA (4.6 %). Finally, a novel,scientifically validated, and the scale-up process has been developed for the preparation of Gym-EEXTalong with an exclusive protocol for isolating its biomarkers.

Ruptured mirror DACA aneurysm: A rare case report and review of literature

Deepak Kumar Singh,Prevesh Kumar Sharma,Arun Kumar Singh,Vipin Kumar Chand 대한뇌혈관외과학회 2023 Journal of Cerebrovascular and Endovascular Neuros Vol.25 No.3

Bilateral distal anterior cerebral artery (DACA) aneurysms also called “kissing aneurysms” or “mirror aneurysm” are extremely rare, accounting for only 0.2% of all intracranial aneurysms. There have only been a few examples of mirror DACA aneurysms reported in the literature. Here, we report a rare case of mirror DACA aneurysm in a middle aged female with its successful clipping. Patient was admitted with severe headache and altered sensorium. Computed tomography (CT) head was suggestive of anterior inter-hemispheric hematoma. Digital subtraction angiography (DSA) was done which was suggestive of two distal anterior cerebral artery aneurysms located at same anatomical position. It was treated through microsurgical clipping. Mirror image DACA aneurysms are rare occurrence. All patients with ruptured DACA aneurysms should have angiography with 3D reconstruction studies. This aids in determining the aneurysm’s morphology and planning treatment accordingly.

A Finite Element Modeling of Low Velocity Impact in Laminated Composite Using Continuum Shell element

Deepak Kumar,Jin-Hwe Kweon,Jin-Ho Choi 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

Low velocity impact is considered potentially dangerous for a composite structure mainly because, the damage in the form of delamination and matrix cracking. To be able to assess the critical nature of the induced damage, a thorough study of damage mechanism is needed. The main challenge is to predict damage initiation and propagation of low velocity impact-induced damage by the use of damage mechanism. For the damage evolution law, stress and fracture mechanics based failure criteria is applied. Damage model is implemented in FEM code ABAQUS. The results show good agreement with the existing experimental results.

Application of Adaptive Neuro-Fuzzy Inference System for Evaluating Compressive Strength of Concrete

Deepak Kumar Sinha,Rupali Satavalekar,Senthil Kasilingam 한국지능시스템학회 2021 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.21 No.2

The objectives of this study are to develop a model for predicting the compressive strength of concrete using an adaptive neuro-fuzzy inference system (ANFIS) and validate the mix proportion using artificial neural networks (ANNs) and by experimentation. A model was developed, and the compressive strength was predicted using the ANFIS (with the subtractive clustering method of the fuzzy inference system) by MATLAB programming. In the present study, two ANFIS models were considered: ANFIS models-1 and -2. ANFIS model-1 was developed to predict the 3-day compressive strength, whereas ANFIS model-2 predicts the 28-day compressive strength by considering the 3-day compressive strength data obtained using ANFIS model-1. It was observed that the errors in the 3- and 28-day compressive strengths were 6.33%, and 17.07%, respectively. Furthermore, experiments were performed for selective mixes-M40, M50, and M60-to verify the compressive strength obtained using the ANFIS model. The model results were verified against the experimental ones based on the mixes selected from the model, and the results were found to agree with the predicted ones, with a maximum deviation of 18%. Furthermore, an ANN model was developed to predict the compressive strength to verify the accuracy of the ANFIS model. The results predicted by the ANFIS and the ANN were compared with the original results available in the literature. A significant deviation was found between the ANN model results and the original results, however, the ANN model results presented the same trend as the original results. It was concluded that the ANFIS model results were highly consistent with the original results.

FPGA application for wireless monitoring in power plant

Kumar, Adesh,Bansal, Kamal,Kumar, Deepak,Devrari, Aakanksha,Kumar, Roushan,Mani, Prashant Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.4

The process of automation and monitoring in industrial control system involves the use of many types of sensors. A programmable logic controller plays an important role in the automation of the different processes in the power plant system. The major control units are boiler for temperature and pressure, turbine for speed of motor, generator for voltage, conveyer belt for fuel. The power plant units are controlled using microcontrollers and PLCs, but FPGA can be the feasible solution. The paper focused on the design and simulation of hardware chip to monitor boiler, turbine, generator and conveyer belt. The hardware chip of the plant is designed in Xilinx Vivado Simulator 17.4 software using VHDL programming. The methodology includes VHDL code design, simulation, verification and testing on Virtex-5 FPGA hardware. The system has four independent buzzers used to indicate the status of the boiler, generator, turbine motor and conveyer belt in on/off conditions respectively. The GSM is used to display corresponding message on the mobile to know the status of the device in on/off condition. The system is very much helpful for the industries working on plant automation with FPGA hardware integration.

Synthesis, Antioxidant and Molecular Docking Studies of (-)-Catechin Derivatives

Kumar, Deepak,Kumar, Raj,Ramajayam, R.,Lee, Keun Woo,Shin, Dong-Soo Korean Chemical Society 2021 대한화학회지 Vol.65 No.2

12 kinds of (-)-catechin derivatives were designed and synthesized. The catechin derivatives were evaluated their antioxidant activities using DPPH method. Most of them showed good antioxidant activity, particularly compounds 1d, 1e and 1j exhibited more activity than butylated hydroxytoluene (BHT). Molecular docking studies for compounds 1d, 1e and 1j with STAT1 showed not only sufficent characteristics binding cavity but also agreement with the observed biological activity. Acording to docking results, the compounds showed greater than hydrogen bonding, hydrophobic interactions, electrostatic interactions, and Van der Waals interactions as compared to the reference compound. They formed hydrogen bonds with important residues such as Lys566, His568, Leu570, and Phe644. The compounds showed a novel hydrogen bonding interaction with Arg649, which was not reported previously. Our results might suggest the compounds could serve as a novel anti-oxidant agent.

Microwave-assisted Synthesis, Characterization of Reduced Graphene Oxide, and Its Antibacterial Activity

Deepak Kumar,C. M. Raghavan,Ch. Sridhar,신지항,류성훈,장기완,신동수 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.8

In this study, a facile, fast, and cost-effective method for the synthesis of high-quality reduced graphene oxide sheets is reported by a microwave-assisted chemical reduction using hydroiodic acid/acetic acid as reducing agent. Exposure of graphene oxide (GO) with microwave irradiation (4 and 7 h) was found to be more rapid and sustainable reduction as compared to that of the conventional chemical reduction process (48 h). Formation of high-quality microwave-assisted reduced GO (mrGO) was ensured by means of electron microscopies, Raman, and infrared spectroscope studies. Furthermore, the antibacterial activity was evaluated for the mrGO, which showed good inhibitory effect against both Gram positive and Gram negative bacteria.

DNA Ploidy and S-phase Fraction Analysis in Paediatric B-cell Acute Lymphoblastic Leukemia Cases: a Tertiary Care Centre Experience

Kumar, Banothu Kiran,Bhatia, Prateek,Trehan, Amita,Singh, Ajit Pal,Kaul, Deepak,Bansal, Deepak Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17

DNA ploidy is an important prognostic parameter in paediatric B-ALL, but the significance of the S-phase fraction is unclear. In present study, DNA ploidy was assessed in 40 pediatric B-ALL cases by flow cytometry. The DI (DNA index) and percentage of cells in S-phase were calculated using Modfit software. Aneuploidy was noted in 26/40 (65%) cases. A DI of 1.10-1.6 (hyperdiploidy B) was noted in 20/40 (50%) and 6/40 (15%) had a DI>1.60 (triploid and tetraploid range). Some 14/40 (35%) cases had a diploid DI between 0.90-1.05. None of the cases had a DI <0.90 (hypodiploid) or in the 1.06-1.09 (hyperdiploid A) range. The mean S-phase fraction was 2.6%, with 24/40 (60%) having low and 16/40 (40%) high S-phase fractions. No correlation was noted with standard ALL risk and treatment response factors with DI values or S-phase data, except for a positive correlation of low S-phase with high NCI risk category (p=0.032). Overall frequency of hyperdiploidy in our cohort of B-ALL patients was very high (65%). No correlation between hyperdiploidy B and low TLC or common B-phenotype was observed in our study as 42% cases with DI 1.10-1.6 had TLC> $50{\times}10^9$ and 57.1% CD 10 negativity. The study also highlighted that S-phase fraction analysis does not add any prognostic information and is not a useful parameter for assessment in ALL cases. However, larger studies with long term outcome analysis are needed to derive definitive conclusions.