Single-bit digital comparator circuit design using quantum-dot cellular automata nanotechnology

Vijay Kumar Sharma 한국전자통신연구원 2023 ETRI Journal Vol.45 No.3

The large amount of secondary effects in complementary metal-oxide-semiconductor technology limits its application in the ultra-nanoscale region. Circuit designers explore a new technology for the ultra-nanoscale region, which is the quantum-dot cellular automata (QCA). Low-energy dissipation, high speed, and area efficiency are the key features of the QCA technology. This research proposes a novel, low-complexity, QCA-based one-bit digital comparator circuit for the ultra-nanoscale region. The performance of the proposed comparator circuit is presented in detail in this paper and compared with that of existing designs. The proposed QCA structure for the comparator circuit only consists of 19 QCA cells with two clock phases. QCA Designer-E and QCA Pro tools are applied to estimate the total energy dissipation. The proposed comparator saves 24.00% QCA cells, 25.00% cell area, 37.50% layout cost, and 78.11% energy dissipation compared with the best reported similar design.

Evaluation of responses of semi-rigid frames at target displacements predicted by the nonlinear static analysis

Vijay Sharma,Mahendra K. Shrimali,Shiv D. Bharti,Tushar K. Datta 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.4

Responses of semi-rigid frames having different degrees of semi-rigidity obtained by the nonlinear static analysis (NSA) are evaluated at specific target displacements by comparing them with those obtained by the nonlinear time-history analysis (NTHA) for scaled earthquakes. The peak ground accelerations (PGA) of the earthquakes are scaled such that the obtained peak top story displacements match with the target displacements. Three different types of earthquakes are considered, namely, far-field and near-field earthquakes with directivity and fling-step effects. In order to make the study a comprehensive one, three degrees of semi-rigidity (one fully rigid and the other two semi-rigid), and two frames having different heights are considered. An ensemble of five-time histories of ground motion is included in each type of earthquake. A large number of responses are considered in the study. They include the peak top-story displacement, maximum inter-story drift ratio, peak base shear, total number of plastic hinges, and square root of sum of the squares (SRSS) of the maximum plastic hinge rotations. Results of the study indicate that the nonlinear static analysis provides a fairly good estimate of the peak values of top-story displacements, inter-story drift ratio (for shorter frame), peak base shear and number of plastic hinges; however, the SRSS of maximum plastic hinge rotations in semi-rigid frames are considerably more in the nonlinear static analysis as compared to the nonlinear time history analysis.

Behavior of semi-rigid steel frames under near- and far-field earthquakes

Vijay Sharma,Mahendra K. Shrimali,Shiv D. Bharti,Tushar K. Datta 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.5

The realistic modeling of the beam-column semi-rigid connection in steel frames attracted the attention of many researchers in the past for the seismic analysis of semi-rigid frames. Comparatively less studies have been made to investigate the behavior of steel frames with semi-rigid connections under different types of earthquake. Herein, the seismic behavior of semi-rigid steel frames is investigated under both far and near-field earthquakes. The semi-rigid connection is modeled by the multilinear plastic link element consisting of rotational springs. The kinematic hysteresis model is used to define the dynamic behavior of the rotational spring, describing the nonlinearity of the semi-rigid connection as defined in SAP2000. The nonlinear time history analysis (NTHA) is performed to obtain response time histories of the frame under scaled earthquakes at three PGA levels denoting the low, medium and high-level earthquakes. The other important parameters varied are the stiffness and strength parameters of the connections, defining the degree of semi-rigidity. For studying the behavior of the semi-rigid frame, a large number of seismic demand parameters are considered. The benchmark for comparison is taken as those of the corresponding rigid frame. Two different frames, namely, a five-story frame and a ten-story frame are considered as the numerical examples. It is shown that semi-rigid frames prove to be effective and beneficial in resisting the seismic forces for near-field earthquakes (PGA ≈ 0.2g), especially in reducing the base shear to a considerable extent for the moderate level of earthquake. Further, the semi-rigid frame with a relatively weaker beam and less connection stiffness may withstand a moderately strong earthquake without having much damage in the beams.

A novel approach for designing of variability aware low-power logic gates

Vijay Kumar Sharma 한국전자통신연구원 2022 ETRI Journal Vol.44 No.3

Metal-oxide-semiconductor field-effect transistors (MOSFETs) are continuously scaling down in the nanoscale region to improve the functionality of integrated circuits. The scaling down of MOSFET devices causes short-channel effects in the nanoscale region. In nanoscale region, leakage current components are increasing, resulting in substantial power dissipation. Very large-scale integration designers are constantly exploring different effective methods of mitigating the power dissipation. In this study, a transistor-level input-controlled stacking (ICS) approach is proposed for minimizing significant power dissipation. A low-power ICS approach is extensively discussed to verify its importance in low-power applications. Circuit reliability is monitored for process and voltage and temperature variations. The ICS approach is designed and simulated using Cadence’s tools and compared with existing low-power and high-speed techniques at a 22-nm technology node. The ICS approach decreases power dissipation by 84.95% at a cost of 5.89 times increase in propagation delay, and improves energy dissipation reliability by 82.54% compared with conventional circuit for a ring oscillator comprising 5-inverters.

How an Occluded Artery Recanalizes during Acute Stroke Thrombolysis

Vijay K Sharma,Leonard LL Yeo,Hock L Teoh 한국심초음파학회 2015 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.23 No.1

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Seismic demand assessment of semi-rigid steel frames at different performance points

Vijay Sharma,Mahendra K. Shrimali,Shiv D. Bharti,Tushar K. Datta 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.5

The seismic performance of rigid steel frames is widely investigated, but that of semi-rigid (SR) steel frames are not studied extensively, especially for near-field earthquakes. In this paper, the performances of five and ten-story steel SR frames having different degrees of semi-rigidity are evaluated at four performance points in the four different deformation states, namely, the elastic, elasto-plastic, plastic, and near collapse states. The performances of the SR frames are measured by the response parameters including the maximum values of the top floor displacement, base shear, inter-story drift ratio, number of plastic hinges, and SRSS of plastic hinge rotations. These response parameters are obtained by the capacity spectrum method (CSM) using pushover analysis. The validity of the response parameters determined by the CSM is evaluated by the results of the nonlinear time history analysis (NLTHA) for both near and far-field earthquakes at different PGA levels, which are consistent with the performance points. Results of the study show that the plastic hinges of SR frame significantly increase in the range of plastic to near-collapse states for both near and far-field earthquakes. The effect of the degree of semi-rigidity is pronounced only at higher degrees of semi-rigidity. The predictions of the CSM are fairly well in comparison to the NLTHA.

레이저 및 초음파 표면개질 공정기술에 의한 고엔트로피 합금의 잔류응력 발생

Anurag Sharma(A. Sharma),Vijay Vasudevan(V. Vasudevan),김정석(C. S. Kim) 한국기계가공학회 2021 한국기계가공학회 춘추계학술대회 논문집 Vol.2021 No.6

Incidence of Dural Tears in Open versus Minimally Invasive Spine Surgery: A Single-Center Prospective Study

Sharma Ayush,Shakya Akash,Singh Vijay,Deepak Priyank,Mangale Nilesh,Jaiswal Ajay,Marathe Nandan 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.4

Study Design: A prospective comparative study. Purpose: To compare the incidence of unintended durotomy and return to work after open surgery versus minimally invasive spine surgery (MIS) for degenerative lumbar pathologies. Overview of Literature: The incidence of accidental durotomy varies between 0.3% and 35%. Most of these are from open surgeries, and only a handful of studies have involved the MIS approach. No single-center studies have compared open surgery with MIS, especially in the context of early return to work and dural tear (DT). Methods: This study included 420 operated cases of degenerative lumbar pathology with a prospective follow-up of at least 6 months. Patients were divided into the open surgery and MIS groups, and the incidences of DT, early return to work, and various demographic and operative factors were compared. Results: A total of 156 and 264 patients underwent MIS and open surgery, respectively. Incidental durotomy was documented in 52 cases (12.4%); this was significantly less in the MIS group versus the open surgery group (6.4% vs. 15.9%, p<0.05). In the open surgery group, four patients underwent revision for persistent dural leak or pseudomeningocele, but none of the cases in the MIS group had revision surgery due to DT-related complications. The incidence of DT was higher among patients with high body mass index, patients with diabetes mellitus, and patients who underwent revision surgery (p<0.05) regardless of the approach. The MIS group returned to work significantly earlier. Conclusions: MIS was associated with a significantly lower incidence of DT and earlier return to work compared with open surgery among patients with degenerative lumbar pathology.

A retrospective analysis of mandibular fractures in Mewat, India

Vijay Laxmy Malhotra,Amita Sharma,Rajiv Tanwar,Meenu Dhiman,Radhey Shyam,Depinder Kaur 대한구강악안면외과학회 2021 대한구강악안면외과학회지 Vol.47 No.5

Objectives: Mandibular fractures vary significantly with respect to epidemiological and demographic parameters among populations. To date, no study has evaluated these aspects of mandibular fractures in Nuh, Mewat, Haryana, India. To retrospectively analyze the incidence, age and sex distributions, etiology, anatomic distribution, occlusal status, treatment modality provided, and their correlation in patients who suffered isolated mandibular fractures. Materials and Methods: The records of maxillofacial injury patients who reported to the Department of Dentistry, SHKM Government Medical College from January 2013 to December 2019, were retrieved from our database, and necessary information was collected. The data collected were analyzed statistically using IBM SPSS ver. 21. Results: Totals of 146 patients and 211 fractures were analyzed. There were 127 males and 19 females with an age range of 3-70 years (mean age, 26 years). Road traffic accident (RTA) was the most common cause of fracture (64.4%), followed by fall (19.9%), assault (15.1%), and sports injury (0.7%). Of all patients, 42.5% had bilateral fractures, 31.5% had left side fracture, 21.2% had right side fracture, 3.4% sustained midline symphyseal fracture, and 1.4% had symphyseal fracture along one side of the mandible. Site distribution was as follows: parasymphysis (34.6%), angle (23.7%), condyle (20.4%), body (12.8%), symphysis (4.3%), ramus 2.4%, and dentoalveolar 1.9%. The most common facture combination was angle with parasymphysis (17.8%). Occlusion was disrupted in 69.2% patients. Closed reduction was the predominant treatment modality. Conclusion: The data obtained from retrospective analyses of maxillofacial trauma increase the understanding of variables and their outcomes among populations. The results of the present study are comparable to those of the literature in some aspects and different in others.

Laser Surface Texturing in Powder Bed Fusion (PBF): Numerical Simulation and Experimental Characterization

Vijay Mandal,Shashank Sharma,Sudhanshu S. Singh,J. Ramkumar 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

Laser surface texturing can improve the surface properties of the metallic components. In this work, surface texturing hasbeen carried in a powder bed fusion of Inconel 718 (IN718) rather than material removal process. A 2D fnite element method(FEM) has been built to simulate the thermo-fuidic dynamics of surface texturing, incorporating the phase-feld method inthe preplaced IN718 powder. The temperature and induced velocity felds have been predicted using transient heat transferand fuid fow based on the conservation of mass, momentum, and energy in the melt pool. Furthermore, the roles of drivingforces such as Marangoni force, recoil pressure, and thermal buoyancy force on the melt pool behavior have been evaluated. Micro-textures were developed using laser on the powder bed by using diferent scanning patterns, such as line, circle, hatchand convex dimple. The efect of process parameters (pitch distance, number of pulses and number of layers) on the surfacehydrophobicity were evaluated by measuring the contact angle, where the convex dimple texture exhibited the maximumcontact angle. The hydrophobicity was afected by the ripples (2nd level of roughness) on the surface, which increased withan increase in number of pulses.