Anomalous Stark effect and optical properties of exciton in a quantum dot with linear potential under ionized donor hydrogenic impurity

Varsha,Arora Monika,Gambhir Monica,Prasad Vinod 한국물리학회 2023 Current Applied Physics Vol.48 No.-

Wannier-Mott (W-M) exciton is studied under the confinement of linear potential in a Spherical Quantum Dot (QD) with ionized donor hydrogenic impurity (IDHI). Using electric field excitonic transitions have been used to explore the optical properties of the above-said system. Time independent Schrödinger equation is solved numerically using effective mass approximation. The response of Absorption Coefficients (ACs) as a function of excitonic transition, electric field, and intensity of the laser field is investigated. Optical properties get drastically modified under confinement. The effect of IDHI is also studied in ACs for exciton in linear potential under spherical QD for the first time.

From 3D to 4D Printing – Design, Material and Fabrication for Multi-Functional Multi-Materials

Varsha Khare,추원식,안성훈,Sonkaria Sanjiv Kumar,이길용 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.4 No.3

In the era of multi-dimensional digital printing technology, engineering by multilayered ‘top-down’ methodologies are redefining manufacturing processes at multi-scale levels with atomic precision permitting unprecedented freedom to design complex structures at will. This challenges the current perception of conventional machining processes for unconventional materials (e.g. smart-stimuli responsive materials) that pose limitations in closing the gap between manufacturing processes and the increasing demand for rapid assembly procedures, miniaturized and cost-effective products predicted for emerging industries supplying innovative products to a rising population of end users. Driven by a growing need for customization, printing technologies are dynamically changing to meet the demands of a global market. Here, the conceptualization of 4D printing (4DP) platform and its impact on manufacturing scales and processes are discussed. Further, a ‘new’ conceptual insight into 4DP, high precision material design and the ‘envisioned’ roadmap for 4DP manufacturing is proposed.

Physicochemical and pharmacokinetic evaluation of rosuvastatin loaded nanostructured lipid carriers: influence of long- and medium-chain fatty acid mixture

Varsha Pokharkar,Arpana Patil‑Gadhe,Gursheen Kaur 한국약제학회 2018 Journal of Pharmaceutical Investigation Vol.48 No.4

Combination of long and medium chain lipids show different behavior in-vivo and contribute differently for bioavailability. Aim of the present study was to evaluate the effect of long chain- (LCFA) and medium-chain (MCFA) fatty acid lipids on the bioavailability of rosuvastatin from rosuvastatin loaded nanostructured lipid carrier (RNLC). Lauric acid and capryol-90™ were selected as MCFA whereas stearic acid and oleic acid were chosen as LCFA. RNLC was prepared using melt-emulsification– ultrasonication method using different combinations of MCFA and LCFA. Non-ionic, non-toxic MYS-25 was used as stabilizing agent. RNLC showed entrapment efficiency of 85–92% denoting it to be beneficial for prolonged release of drug after oral administration. Zeta potential of −26.79 mV signifies particle stability through the repulsive forces which prevents aggregation upon storage. In-vivo oral pharmacokinetic study demonstrated six to ninefold improvement in the bioavailability of rosuvastatin (RSVS) in the form of RNLC than RSVS-Aqueous dispersion. A 1.5-fold increase in bioavailability was observed when RNLC was prepared with LCFA solid lipid and MCFA liquid lipid combination as compared to RNLC prepared using only MCFA as both solid and liquid lipid. Use of LCFA and MCFA combination was found to be superior as lipid mixture for the RNLC.

Neural network prediction of fluidized bed bioreactor performance for sulfide oxidation

Varsha Midha,Mithilesh Kumar Jha,Apurba Dey 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2

Sulfide oxidation rate of a fluidized bed bioreactor was predicted using ANN, with upflow velocity, hydraulic retention time, reactor operation time and pH given as input. The reactor was fed with 100mg/L synthetic sulfide wastewater after biofilm formation on nylon support particles. Feedforward neural network model was prepared using 81 data sets, of which 63 were used for training and 18 for testing in a three-way cross validation. Prediction performance of the network was evaluated by calculating the percent error of each data set and mean square error for test data set in three partitions. The mean square error for test data set was 5.55, 4.08 and 2.30 for partition 1, partition 2 and partition 3, respectively. The predicted sulfide oxidation values correlated with the experimental values and a correlation coefficient of 0.96, 0.97 and 0.98 was obtained for partition 1, partition 2 and partition 3, respectively.

Classification and surgical management of temporomandibular joint ankylosis: a review

Varsha Haridas Upadya,Hari Kishore Bhat,B.H. Sripathi Rao,Srinivas Gosla Reddy 대한구강악안면외과학회 2021 대한구강악안면외과학회지 Vol.47 No.4

The paper reviews various classifications and surgical techniques for the treatment of temporomandibular joint ankylosis. PubMed, EBSCO, Web of Science, and Google Scholar were searched using a combination of keywords. Articles related to classification, resection-reconstruction of the temporomandibular joint, and management of airway obstruction were considered and categorized based on the objectives. Seventy-nine articles were selected, which included randomized clinical trials, non-randomized controlled cohort studies, and case series. Though several classifications exist, most classifications are centered on the radiographic extent of the ankylotic mass and do not include the clinical and functional parameters. Hence there is a need for a comprehensive staging system that takes into consideration the age of the patient, severity of the disease, clinical, functional, and radiographic findings. Staging the disease will help the clinician to adopt a holistic approach in treating these patients. Interpositional arthroplasty (IA) results in better maximal incisal opening compared with gap arthroplasty, with no significant difference in recurrent rates. Distraction osteogenesis (DO) is emerging as a popular technique for the restoration of symmetry and function as well as for relieving airway obstruction. IA, with a costochondral graft, is recommended in growing patients and may be combined with or preceded by DO in cases of severe airway obstruction. Alloplastic total joint replacement combined with fat grafts and simultaneous osteotomy procedures are gaining popularity. A custom-made total joint prosthesis using CAD/CAM can efficiently overcome the shortcomings of stock prostheses.

Chemical Speciation of Iron in Soil determined using X-ray Absorption Spectroscopy

Varsha Singh,So Hee Kim,Hee Kyoung Kang,Weon Cheol Lim,Jaeyeoul Kim,Keun Hwa Chae 한국진공학회 2020 한국진공학회 학술발표회초록집 Vol.2020 No.2

Ca K-edge EXAFS studies of calcium carbonate

Varsha Singh,Weon Cheol Lim,Jitendra Pal Singh,Sangsul Lee,Keun Hwa Chae 한국진공학회 2019 한국진공학회 학술발표회초록집 Vol.2019 No.2

A Single-Phase Cell-Based Asymmetrical Cascaded Multilevel Inverter

Varsha Singh,Swapnajit Pattnaik,Shubhrata Gupta,Bokam Santosh 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

A single-phase asymmetrical cascaded multilevel inverter is introduced with the goal of increasing power quality with the reduction of power in insulated-gate bipolar transistor (IGBT) switches. In the present work, the proposed inverter topology is analyzed and generalized with respect to different proposed algorithms for choosing different voltage source values. To prove the advantages of the proposed inverter, a case study involving a 17-level inverter is conducted. The simulation and experimental results with reduced THD are also presented and compared with the MATLAB/SIMULINK simulation results. Finally, the proposed topology is compared with different multilevel inverter topologies available in the literature in terms of the number of IGBT switches required with respect to the number of levels generated in the output of inverter topologies.

Graphene–Ionic Liquid Based Hybrid Nanomaterials as Novel Lubricant for Low Friction and Wear

Khare, Varsha,Pham, Minh-Quan,Kumari, Nitee,Yoon, Hae-Sung,Kim, Chung-Soo,Park, Jae-IL,Ahn, Sung-Hoon American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.10

<P>Hybrid nanomaterials offer potential scope for an increasing number of novel applications when engineered to deliver usefully functional properties. Recent advancements in the design of new material products that result from interactions among different compositions at the nanoscale and microscale has led to innovative ways to fabricate and process hybrids with altered structural physicochemical properties. An example is the development of novel “lubricants” that make use of ionic liquids (ILs) and their ability to induce exploitable molecular assemblies at the IL–graphene interface. In the present study, we report the potential of graphene–IL hybrid nanomaterials for engineering applications with a focus on “lubricant” properties to reduce frictional forces to enhance tribological performance. The present contribution outlines the wear and tribological properties (friction and lubrication) of a highly viscous IL [BMIM][I] and its comparison with its nanohybrid material counterpart. Detailed structural–microstructural investigations of the nanohybrid materials were performed using X-ray diffraction and microscopic techniques employing scanning electron (SEM), transmission electron (TEM), and high resolution transmission electron (HRTEM) microscopies. A comparative study of the morphology of friction track and wear behavior was assessed by SEM and TEM. These characteristic properties within and outside the friction track were further correlated with physical and chemical interactions obtained by contact angle measurements and Raman spectroscopy and energy dispersive analysis by X-ray (EDAX).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-10/am302761c/production/images/medium/am-2012-02761c_0016.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am302761c'>ACS Electronic Supporting Info</A></P>

A Single-Phase Cell-Based Asymmetrical Cascaded Multilevel Inverter

Singh, Varsha,Pattnaik, Swapnajit,Gupta, Shubhrata,Santosh, Bokam The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

A single-phase asymmetrical cascaded multilevel inverter is introduced with the goal of increasing power quality with the reduction of power in insulated-gate bipolar transistor (IGBT) switches. In the present work, the proposed inverter topology is analyzed and generalized with respect to different proposed algorithms for choosing different voltage source values. To prove the advantages of the proposed inverter, a case study involving a 17-level inverter is conducted. The simulation and experimental results with reduced THD are also presented and compared with the MATLAB/SIMULINK simulation results. Finally, the proposed topology is compared with different multilevel inverter topologies available in the literature in terms of the number of IGBT switches required with respect to the number of levels generated in the output of inverter topologies.