Quantitative evaluation of grain boundary sliding and its dependence on orientation and temperature in pure Zn

Gokhale, Aditya,R, Sarvesha,Huang, E-Wen,Lee, Soo Yeol,Prasad, Rajesh,Singh, Sudhanshu S.,Jain, Jayant Elsevier 2019 Materials letters Vol.246 No.-

<P><B>Abstract</B></P> <P>In the present work, grain boundary sliding (GBS) has been studied for the grains exhibiting different orientations (for indentation parallel and perpendicular to < c > axis) at different temperatures (RT to 200 °C) using nanoindentation in pure Zn. Electron back scattered diffraction was utilized to determine the orientation of the indented grains and identify the deformation mechanism, whereas atomic force microscopy was utilized to systematically quantify the GBS. Results indicated that indentation perpendicular to < c > axis exhibits slip induced GBS, whereas the indentation parallel to < c > axis results in pure GBS. The amount of GBS was also found to be strongly dependent upon the orientation of the neighboring grain. Further, the contribution from GBS towards total stain was found to increase with an increase in temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First study that characterises orientation and temperature effect on GBS in Zn. </LI> <LI> Indentation perpendicular to <c> axis exhibits slip induced GBS. </LI> <LI> Indentation parallel to <c> axis results in pure GBS. </LI> <LI> The contribution of GBS increases with an increase in temperature. </LI> </UL> </P>

CME Bitcoin Futures Market: Challenges in Bitcoin Price Discovery

Hemangi Gokhale 한국국제경영관리학회 2018 국제경영리뷰 Vol.22 No.3

2017년 12월에 시카고상업거래소(CME)는 비트코인 선물 계약(futures contracts) 서비스를 위한 최초의 공인 비트코인 선물시장을 열었다. 선물 계약은 시장 참가자들에게 가격 발견, 보험 및 가격 투기를 위한 집중화된 메커니즘을 제공하는 금융상품이다. 따라서 이 금융상품은 비전통적 상품(예: ETF 선물) 또는 가격변동성이 높은 상품(예: 코코아 선물)을 거래하는 데 널리 사용되는 금융상품이다. 비트코인은 개인간 거래를 허용하는 비전형적인 디지털 상품 및 결제시스템이다(Nakato, 2008). 비트코인의 상품-통화의 2중적 특성과 제한된 공급으로 인하여, 비트코인 가격은 역사적으로 매우 변동성이 높아 왔다. 비트코인은 가격변동성이 높은 비전통적 상품이기 때문에 시카고상 업거래소(CME)가 비트코인 가격통합을 실현할 것이라는 기대가 높았다. 그러나 시카고상업거래소(CME)의 비트코인 선물시장이 비트코인 가격 발견을 실현할 수 있을까? 이 논문은 그 가능성이 있다고 결론을 내리지만, 최초의 시카고상업거래소(CME)는 단기적(3년)으로 근본적인 과제(특히 비트코인 선물계약 평가, 비트코인 가격 예측, 많은 거래 규모의 유지 및 비트코인 선물시장의 실효성을 유지하지 위한 공중의 이익과 관련된 우려)를 다루어야 할 것이다. 이 논문의 제1장에서는 선물시장, 가격통합이론을 검토하고, 시카고상업거래소(CME) 비트코인 선물시장에 대한 계약 세부내용을 제공한다. 이 논문의 제2장은 시카고상업거래소(CME) 비트코 인 선물시장이 계약가격의 정확성과 시장 효율성을 향상시키기 위한 필요성을 강조한다. 이 논문의 마지막 장에서는 연구결과를 정리하고, 연구 문제의 중요성을 강조하며, 비트코인 가격통합에 대한 추가 연구를 위한 제안을 한다. 비트코인 선물시장 및 비트코인 가격(비트코인은 전 세계적으로 다르게 분류되며 공인 또는 비공인 거래소에서는 가격이 상이함)에 대한 신뢰성 있는 자료가 부족한 바, 이 논문은 시카고상업 거래소(CME)의 비트코인 가격 발견 가능성을 검토하기 위하여 정성적 분석을 적용하였다. In December 2017, Chicago Mercantile Exchange Group (CME) launched one of the first ever regulated bitcoin futures markets to service bitcoin futures contracts. A futures contract is a financial instrument that provides market participants with a centralized mechanism for price discovery, insurance and price speculation. It is thus a popular tool for trading unconventional commodities (e. g. ETF Futures) or commodities with volatile prices (e. g. Cocoa Futures). Bitcoin is an unconventional digital commodity and payment system that allows for peer to peer transactions (Nakamoto, 2008). Given bitcoin’s dual commodity- currency attributes and its limited supply, bitcoin price has been historically very volatile. Since bitcoin is an unconventional product with high price volatility, there has been much anticipation of CME realizing bitcoin price convergence. But is it truly possible for CME’s bitcoin futures market to achieve bitcoin price discovery? The paper concludes that the possibility exists, but first CME will need to address certain fundamental challenges in the short term (three years); specifically issues related to bitcoin futures contract valuations, bitcoin price forecasting, and concerns related to sustaining high transaction volume and open interest to keep the bitcoin futures market in effect. The first section of the paper reviews futures market, price convergence theory, and provides contract specifications for the CME bitcoin futures market. The second section of the paper highlights the need for CME bitcoin futures market to improve its contract price accuracy and market efficiency. The last section of the paper summarizes findings, highlights importance of the research question and offers suggestions for further research in bitcoin price convergence. Given insufficient reliable data on bitcoin futures markets and bitcoin price (bitcoin is classified differently across the globe and is priced differently on regulated and unregulated exchanges), the paper instead applies qualitative analysis to explore the possibility of CME eventually achieving bitcoin price discovery.

South Korea’s Aging Workforce and Labor Productivity

Hemangi Gokhale 한국혁신학회 2017 한국혁신학회지 Vol.12 No.3

Strong government policies in the 1950s~1960s helped Korea to partake in ‘The East Asian miracle’ (World Bank, 1993). An effective policy environment allowed Korea to take advantage of its first demographic dividend, and to attain rapid industrialization and strong labor productivity within a century (Park, Lee& Mason, 2012). Korea is now the world’s eleventh biggest economy (World Bank, 2017). While a young Korean workforce ushered in domestic economic growth over the last decade, an aging workforce now threatens Korea’s labor productivity prospects. Korea has been aging since the 1970s and in 2018, its elderly (citizens aged 60 years and over) will account for at least 14% of Korean population (Howe, Jackson & Nakashima, 2007). This paper analyzes Korean economic policy alternatives necessary for bridging the forthcoming labor gap, and for sustaining (and improving) Korean labor productivity in the long run amidst an aging workforce. Given an economic policy focus of the paper, a comparative research methodology is applied in analyzing policy alternatives. The paper considers economic policies for aging labor applied in Japan, Germany and US because (a) all three countries have advanced aging policies (Hoehn, 2000; Kim 2010; Achenbaum & Carr, 2014) (b) Japan’s cultural environment and family values are relatively similar to ones in Korea (Kim, 2010) and (c) Korean legal system is similar to German and U.S. legal systems (Jin, 2004). The first section of the paper highlights the urgency in addressing Korea’s aging demographic crisis. The second part of the paper discusses existing government aging policies to enhance labor productivity in its aging workforce. The last section of the paper offers policy suggestions that can add value to existing government policies on sustaining long-term Korean labor productivity.

Effect of deposition orientations on dimensional and mechanical properties of the thin-walled structure fabricated by tungsten inert gas (TIG) welding-based additive manufacturing process

Nitish P. Gokhale,Prateek Kala,Varun Sharma,Murali Palla 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

Welding-based additive manufacturing can potentially produce a cost-effective process for the production of dense metallic parts. Tungsten inert gas (TIG) welding-based additive manufacturing process uses wire as a filler material and offers a high deposition rate with low spattering. In this study, different orientations of wire feeding nozzle and TIG welding torch, such as front wire feeding (FWF), back wire feeding (BWF), and side wire feeding (SWF), were investigated for thin-walled metal deposition with enhanced dimensional accuracy and mechanical properties. The dimensional accuracy of thin-walls deposited at four different orientations were investigated in terms of deposition height and deposition width. The FWF orientation with higher wire feeding angle and SWF orientation produced poor dimensional accuracy in the deposition. FWF orientation with normal wire feeding angle and BWF orientation provided a decent dimensional accuracy and surface appearance. The deposited samples exhibited a similar trend for Vickers microhardness, residual stress, and microstructure for the four different wire feeding orientations.

Dehydration of Red Beet Root (Beta vulgaris) by Hot Air Drying: Process Optimization and Mathematical Modeling

S. V. Gokhale,S. S. Lele 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4

Convective hot air drying was optimized with the objective of maximum color retention of red beet. The process was mathematically modelled as a function of hot air temperature, batch time, and moisture. New semitheoretical model was tested with experimental data (50 to 120^oC) and was found better than 9 other reported models. Estimated effective moisture diffusivity was 3.01×10^−9 to 7.21×10^−7 m^2/s and it obeyed Arrhenius’s equation. Color and rehydration ratio were used to assess the quality of beet powder. An unusual trend of color minima was also observed;which was attributed to the physical phenomena of surface moisture. The final color of beet was temperature dependent and maximum color retention was achieved at lowest drying temperature. Best drying condition required sequential reduction in temperature (120 to 50ºC) resulting in good color retention. This reduced batch time to 4 h compared to 6 h batch of conventional isothermal drying at 50ºC.

Mid-term quasi-periodicities in the CaII-K plage index of the Sun and their implications

Chowdhury, Partha,Gokhale, M. H.,Singh, Jagdev,Moon, Y.-J. D. Reidel 2016 Astrophysics and space science Vol.361 No.2

<P>We present results of the fast Fourier transform (FFT), the MEM analysis, and the wavelet analysis (WA), of the temporal variation of the monthly disk integrated 'CaII-K plage-area and enhanced network (EN) area' hereafter called 'plage index' derived by Tlatov et al. (2009), from spectro-heliograms taken in Ca II K line at Kodaikanal Observatory, from February 1907 to April, 1998, In the range >3 months and < decade, the Fourier transform power spectra reveal solar cycle periodicity similar to 122 months, its sub-harmonic similar to 61 months, two short quasi-periodicities (>2 and <4 months), and nine 'intermediate-range' quasi-periodicities (greater than or similar to 4 mo and <11 yr), in the variation of the plage index. The quasi-periodicities include Rieger, Rieger type and quasi-biennial. The presence of quasi-periodicities and the mean values of the periods are confirmed by the maximum entropy method (MEM). The temporal spans of the quasi-periodicities during different solar cycles are determined from the complex Morlet-wavelet analyses. The Rieger quasi-periodicity (150-160 days) appeared during cycle 21 and cycle 22. Each of the quasi-periodicities in the studied range lies close to one or more planetary periodicities (orbital, or spring tidal, or heliocentric conjunction frequency). We discuss possible interpretations of our results, and those of similar results obtained earlier by other authors, towards understanding the mechanisms of excitation of various quasi-periodicities detected in solar variability parameters.</P>

Sialoglycoproteins of Mammalian Erythrocyte Membranes: A Comparative Study

Sharma, Savita,Gokhale, Sadashiv M. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.12

The presence of sialoglycoproteins (SGPs) in the membranes from goat (Capra aegagrus hircus), buffalo (Bubalus bubalis bubalis) and pig (Sus scrofa domestica) erythrocytes was investigated by partial purification with a chloroform-methanol extraction method followed by Sodium dodecyl sulphate - Polyacrylamide gel electrophoresis in comparison to human (Homo sapiens) erythrocytes. The results show that mammalian erythrocytes possess clear differences in the SGPs numbers and molecular weights although all animals studied in this experiment are from the same class i.e. mammalia. The SGPs number in human, goat, buffalo and pig are four (PAS-1 to PAS-4), ten (PAS-GI to PAS-GX), seven (PAS-BI to PAS-BVII) and four (PAS-PI to PAS-IV) respectively as indicated by staining the polyacrylamide gel with sialoglycoprotein-specific Periodic acid-Schiff's (PAS) stain. The new SGPs could be observed only after the partial purification of membrane fractions named as PAS-HI with molecular weight (Mr) 190 kDa and PAS-HII 150 kDa in human, PAS-BIA in buffalo and PAS-PIA and PAS-PIVA in pig. The gels were also stained with Coomassie brilliant blue (CBB) and Silver stain to check the contamination of other membrane proteins in the purified fractions. The quantitative distribution of SGPs was also determined by densitometry. Present study indicates that there are some basic differences in mammalian erythrocyte membrane SGPs, especially with respect to their number and molecular weights indicating major structural variations.

Prediction of Variability in the Mechanical Properties of Pressure Die-Cast Mg Alloys (초)

이순기,( Arun M. Gokhale ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속재료학회 학술대회 개요집 Vol.2007 No.1

Acetabular Defect Reconstruction with Trabecular Metal Augments: Study with Minimum One-year Follow-up

( Chirayu Dwivedi ),( Sandeep Gokhale ),( Hyun Gon Khim ),( Jeon Keon Oh ),( Won Yong Shon ) 대한고관절학회 2017 Hip and Pelvis Vol.29 No.3

Purpose: High rates of mechanical failure have been reported in type III acetabular defects. Recently porous trabecular metal augments have been introduced with, excellent biomechanical characteristics and biocompatibility, allowing early stability and greater bone ingrowth. The aim of the study was to assess the short term clinical and radiological outcome of the trabecular metal augments. Materials and Methods: We performed, 22 revision total hip arthroplasties (THA) and 6 primary THA (total 28) using trabecular metal augments to reconstruct acetabular defect between 2011 to 2015. Among 28 patients, 18 were males, 10 females. Mean age of patients was 61.21 years. Paprosky classification for acetabular bone defects was used. Eighteen cases were classified as grade 3 A and 10 cases as grade 3B. Hip center was calculated in each case preoperatively and compared postoperatively to check whether it has been brought down. Clinical outcome assessed using Harris hip score (HHS) and radiological outcomes as osteolysis in acetabular zones and osseointegration, according to Moore`s criteria. Results: HHS improved from 58.00 to 86.20. Centre of rotation of hip joint corrected from 38.90 mm preoperatively to 23.85 mm postoperatively above the interteardrop line. Among 28 patients, 18 patients had three or more signs of osseointegration (Moore`s criteria), during final follow up and 10 had one/two signs. No radiolucency, osteolysis, or loosening found during follow up radiographic examination. Conclusion: Our study showed that trabecular metal augments were highly satisfactory in short term. However, long term study is required for better evaluation.

<i>N6</i>-methyladenosine modification of hepatitis B virus RNA differentially regulates the viral life cycle

Imam, Hasan,Khan, Mohsin,Gokhale, Nandan S.,McIntyre, Alexa B. R.,Kim, Geon-Woo,Jang, Jae Young,Kim, Seong-Jun,Mason, Christopher E.,Horner, Stacy M.,Siddiqui, Aleem National Academy of Sciences 2018 Proceedings of the National Academy of Sciences Vol.115 No.35

<P>N6-methyladenosine (m(6)A) RNA methylation is the most abundant epitranscriptomic modification of eukaryotic messenger RNAs (mRNAs). Previous reports have found m(6)A on both cellular and viral transcripts and defined its role in regulating numerous biological processes, including viral infection. Here, we show that m(6)A and its associated machinery regulate the life cycle of hepatitis B virus (HBV). HBV is a DNA virus that completes its life cycle via an RNA intermediate, termed pregenomic RNA (pgRNA). Silencing of enzymes that catalyze the addition of m(6)A to RNA resulted in increased HBV protein expression, but overall reduced reverse transcription of the pgRNA. We mapped the m(6)A site in the HBV RNA and found that a conserved m(6)A consensus motif situated within the epsilon stem loop structure, is the site for m(6)A modification. The epsilon stem loop is located in the 3' terminus of all HBV mRNAs and at both the 5' and 3' termini of the pgRNA. Mutational analysis of the identified m(6)A site in the 5' epsilon stem loop of pgRNA revealed that m(6)A at this site is required for efficient reverse transcription of pgRNA, while m(6)A methylation of the 3' epsilon stem loop results in destabilization of all HBV transcripts, suggesting that m(6)A has dual regulatory function for HBV RNA. Overall, this study reveals molecular insights into how m(6)A regulates HBV gene expression and reverse transcription, leading to an increased level of understanding of the HBV life cycle.</P>