Performance Evaluation of Modified Low-Temperature Cascade (MLTC) Type Refrigeration System

Siddiqui Mohd Waseem,Das Nishith Kumar,Sahoo R. K. 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.3

An experimental investigation was carried out to study the performance evaluation of Modified Low-Temperature Cascade (MLTC) system, based on two-stage cascade type refrigeration system using the combination of R404A/R23 refrigerants. This system was developed using chilled water (CHW) in the condenser of high-temperature circuit (HTC) and pre-cooler (PC) in the low-temperature circuit (LTC). Isentropic compression efficiency is computed in this work and used here as an important parameter. Performance of MLTC system was compared with or without the introduction of PC into LTC. System’s coefficient of performance (COP) has also been compared with using CHW, cooling tower water (CTW), normal water (NW) into the HTC condenser. It has also been shown that COPs of the system are significantly affected by slight variation in the LTC and HTC evaporating temperatures. Presented parameters and comparisons are likely to help in developing a low-temperature (LT) refrigeration system with higher efficiency for industrial and other applications.

Substrate bias effects during diamond like carbon film deposition by microwave ECR plasma CVD

R.M. Dey,S.B. Singh,A. Biswas,R.B. Tokas,N. Chand,S. Venkateshwaran,D. Bhattacharya,N.K. Sahoo,S.W. Gosavi,S.K. Kulkarni,D.S. Patil 한국물리학회 2008 Current Applied Physics Vol.8 No.1

Diamond like carbon (DLC) coatings were deposited on silicon(11) substrates by microwave electron cyclotron resonance (ECR)plasma CVD process using a plasma of Ar and CH4 gases under the inuence of DC self bias generated on the substrates by applicationof RF (13.56 MHz) power. DLC coatings were deposited under the varying inuence of DC bias (. 60 V to. 150 V) on the Si substrates.atomic force microscopy (AFM), Hardness and elastic modulus determination technique, Raman spectroscopy, scanning electronmicroscopy (SEM) and contact angle measurement. The results indicate that the lm grown at. 100 V bias has optimised propertieslike high sp3/sp2 ratio of carbon bonding, high refractive index (2.262.17) over wide spectral range 4001200 nm, low roughness of0.8 nm, high contact angle (80.) compared to the lms deposited at other bias voltages (. 60 V and . with each other and nd august explanation under the subplantation model for DLC growth.

A Multizone Adaptive Parallel Scheme for Solidification in a Rectangular Cavity

R. K. Sahoo,V.Prasad,H. Zhang,W. K. Chui,F. Tangerman,J. Glimm 대한기계학회 1998 Heat transter conference Vol.7 No.1

Carbon nanoflake growth from carbon nanotubes by hot filament chemical vapor deposition

Sahoo, S.C.,Mohapatra, D.R.,Lee, H.J.,Jejurikar, S.M.,Kim, I.,Lee, S.C.,Park, J.K.,Baik, Y.J.,Lee, W.S. Pergamon Press ; Elsevier Science Ltd 2014 Carbon Vol.67 No.-

We report the growth of carbon nanoflakes (CNFs) on Si substrate by the hot filament chemical vapor deposition without the substrate bias or the catalyst. CNFs were grown using the single wall carbon nanotubes and the multiwall carbon nanotubes as the nucleation center, in the Ar-rich CH<SUB>4</SUB>-H<SUB>2</SUB>-Ar precursor gas mixture with 1% CH<SUB>4</SUB>, at the chamber pressure and the substrate temperature of 7.5Torr and 840<SUP>o</SUP>C, respectively. In the H<SUB>2</SUB>-rich condition, CNF synthesis failed due to severe etch-removal of carbon nanotubes (CNTs) while it was successful at the optimized Ar-rich condition. Other forms of carbon such as nano-diamond or mesoporous carbon failed to serve as the nucleation centers for the CNF growth. We proposed a mechanism of the CNF synthesis from the CNTs, which involved the initial unzipping of CNTs by atomic hydrogen and subsequent nucleation and growth of CNFs from the unzipped portion of the graphene layers.

Catalytic Supplementation of Urea-molasses on Nutritional Performance of Male Buffalo (Bubalus bubalis) Calves

Sahoo, A.,Elangovan, A.V.,Mehra, U.R.,Singh, U.B. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.5

Twenty male buffalo calves of 6-9 months of age (average body weight, 97 kg) were randomly allocated into two main groups of four (control) and sixteen (supplemented) calves. The supplemented group was further divided in to four equal sub-groups, with the two groups supplemented with a liquid preparation of urea-molasses, UML1, containing fish meal and UML2, containing formaldehyde treated deoiled mustard cake (FDMC) and the other two, with a semi-solid preparation, UMC1 with FDMC and deoiled rice bran (DORB) contributing similar level of CP as in UML2 and UMC2 with double the level of FDMC to that in UMC1. The control group was fed with DORB along with ad libitum wheat straw at 40:60 ratios. The rest of the groups were fed on the above diet supplemented with 500 g (as fed basis) of urea-molasses preparations. The experimental feeding was carried out for 24 weeks including a metabolism trial towards the end of experimental feeding. Daily feed intake and fortnightly change in live weight were also recorded during the study. Catalytic supplementation of 500 g urea-molasses induced 8-25% higher voluntary feed intake of wheat straw, resulting in 15-25% higher DM and OM intake. The digestibility of DM, OM, total carbohydrate, NDF, ADF, hemicellulose and cellulose in all the dietary groups were comparable. The CP digestibility of calves in supplemented groups were higher (p<0.05) than the control group. The balance of nutrients, viz. N, Ca and P, was also higher in the supplemented groups. Significantly higher intake of digestible CP coupled with other digestible nutrients attributed to higher TDN (1.67-1.78 vs. 1.37 kg) and ME (5.94-6.31 vs. 4.87 Mcal) intake in urea-molasses supplemented groups which resulted in higher live weight gain compared to that in control group (p<0.01). Between the supplements, UML2 and UMC2 faired non-significantly, indicating formalin treated mustard cake as a suitable replacement to fishmeal in the supplement. The overall ranking based on intake and digestibility of nutrients, live weight gain, economic evaluation and input-output relationship revealed that the rations with UML2 and UMC1 to be of greater value compared to other types. From the study it can be concluded that young ruminants can be reared successfully on a basal diet of deoiled rice bran and wheat straw supplemented with cheaper urea-molasses-mineral mix.

Vortex induced vibrations and motions - Review, issues and challenges

Sahoo, Patitapaban,Domala, Vamshikrishna,Sharma, R. Techno-Press 2022 Ocean systems engineering Vol.12 No.3

Herein, we report meaningful and selective review of the progress made on 'Vortex Induced Vibration (VIV)' and 'Vortex Induced Motion (VIM)' of 'Structures of Specific Shapes (SoSS)' subjected to steady uniform flow and of relevance to/in marine structures. Important and critical elements of the numerical methods, experimental methods, and physical ideas are listed and analysed critically and the limitations of the current state of art of VIV/VIM are discussed in-detail. Our focus and aim are to analyse the existing researches with respect to the application in analyses, design and production of marine structures and the reported reviews centre on these only. We identify the critical and important issues that exist in the current literature and utilise these issues to highlight the challenges that need to be tackled to design and develop new age marine structures that can exist and operate safely in the areas of dominance by the VIV/VIM. Finally, we also identify some areas for future scope of research on VIV/VIM.

A comparative morphological study of electron beam co-deposited binary optical thin films of HfO2:SiO₂ and ZrO₂:SiO₂

R.B. Tokas,N.K. Sahoo,S. Thakur,N.M. Kamble 한국물리학회 2008 Current Applied Physics Vol.8 No.5

A comparative morphology, grain structure and optical properties studies of reactive electron beam co-evaporated mixed thin films of hafnia–silica (HfO₂:SiO₂) and zirconia–silica (ZrO₂:SiO₂) systems have been carried out using atomic force microscopy and phase modulated ellipsometry. The addition of silica, especially with small fractions, has demonstrated altogether different types of evolutions in the microstructure and morphology in these binary thin film systems possibly forming new solid solution phases. Such morphological evolutions are probed through RMS roughness, power spectral density, height–height correlation and autocorrelation analyses of the topographic data acquired through atomic force microscopy. The present investigations indicated that with composition-control morphological quality improvement is more favourable in composite hafnia–silica over the zirconia–silica films. So for ultraviolet optical coating applications which demand low light scattering thin film microstructure, hafnia–silica binary composite system has a definite edge over the zirconia–silica counterpart. A comparative morphology, grain structure and optical properties studies of reactive electron beam co-evaporated mixed thin films of hafnia–silica (HfO₂:SiO₂) and zirconia–silica (ZrO₂:SiO₂) systems have been carried out using atomic force microscopy and phase modulated ellipsometry. The addition of silica, especially with small fractions, has demonstrated altogether different types of evolutions in the microstructure and morphology in these binary thin film systems possibly forming new solid solution phases. Such morphological evolutions are probed through RMS roughness, power spectral density, height–height correlation and autocorrelation analyses of the topographic data acquired through atomic force microscopy. The present investigations indicated that with composition-control morphological quality improvement is more favourable in composite hafnia–silica over the zirconia–silica films. So for ultraviolet optical coating applications which demand low light scattering thin film microstructure, hafnia–silica binary composite system has a definite edge over the zirconia–silica counterpart.

Growth Performance of Lambs Fed Diet Supplemented with Rice Bran Oil as Such or as Calcium Soap

Bhatt, R.S.,Karim, S.A.,Sahoo, A.,Shinde, A.K. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.6

Forty two Malpura lambs (21 d old) were divided into three groups of 14 each consisting of 8 females and 6 males. Lambs were allowed to suckle their respective dams twice daily up to weaning (13 wks) and offered free choice concentrate and roughage in a cafeteria system. The lambs in control group were fed conventional concentrate mixture, in RBO group concentrate mixture fortified with 4% industrial grade rice bran oil and in Ca-soap rice bran oil (as in RBO group) was supplemented in the form of calcium soap. The concentrate intake decreased($p{\leq}0.05$) in RBO group as a result total dry matter, crude protein and metabolizable energy intake decreased compared to control whereas Ca-soap prepared from the same rice bran oil stimulated the concentrate intake leading to higher total dry matter, crude protein and energy intakes. The digestibility of dry matter ($p{\leq}0.05$), organic matter ($p{\leq}0.05$) and crude protein ($p{\leq}0.05$) was higher in RBO group followed by Ca-soap and control whereas no effect was observed for ether extract digestibility. Higher cholesterol ($p{\leq}0.05$) content was recorded in serum of oil supplemented groups (RBO and Ca-soap) while no effect was recorded for other blood parameters. Rice bran oil as such adversely affected and reduced the body weight gain ($p{\leq}0.001$) of lambs in comparison to control whereas the Ca-soap of rice bran oil improved body weight gain and feed conversion efficiency in lambs. Fat supplementation decreased total volatile fatty acids ($p{\leq}0.05$) and individual volatile fatty acid concentration which increased at 4 h post feeding. Fat supplementation also reduced ($p{\leq}0.05$) total protozoa count. Ca-soap of rice bran oil improved pre slaughter weight ($p{\leq}0.05$) and hot carcass weight ($p{\leq}0.05$). It is concluded from the study that rice bran oil in the form of calcium soap at 40 g/kg of concentrate improved growth, feed conversion efficiency and carcass quality as compared to rice bran oil as such and control groups.

Synchronization and Operation of Parallel Inverters using Droop Control

L. K. Sahoo,N. D. Thakur,K. Rai,P Sensarma,R. D. Jha,P. Mohanty,A Sharma 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

To obtain a continuous power supply Distributed Generation (DG) with a Decentralized Power System (DPS), i.e. replacing a single UPS unit with multiple, smaller units in parallel, is emerging as new paradigm. The technically challenging aspect of DPS is the synchronization of inverters and load sharing among the parallel connected inverters. In this paper, a control method is proposed and implemented for synchronization and parallel operation of inverters. Droop control method has been used for equal power sharing, and design of power control loop. The design issues for voltage control loop are analyzed with the discussion of relative stability of the system. A current control loop is designed and analyzed to provide synchronization between the inverters.

Diverse Structural Conversion and Aggregation Pathways of Alzheimerʼs Amyloid-β (1-40)

Lin, Yuxi,Sahoo, Bikash R.,Ozawa, Daisaku,Kinoshita, Misaki,Kang, Juhye,Lim, Mi Hee,Okumura, Masaki,Huh, Yang Hoon,Moon, Eunyoung,Jang, Jae Hyuck,Lee, Hyun-Ju,Ryu, Ka-Young,Ham, Sihyun,Won, Hyung-Sik American Chemical Society 2019 ACS NANO Vol.13 No.8

<P>Complex amyloid aggregation of amyloid-β (1-40) (Aβ<SUB>1-40</SUB>) in terms of monomer structures has not been fully understood. Herein, we report the microscopic mechanism and pathways of Aβ<SUB>1-40</SUB> aggregation with macroscopic viewpoints through tuning its initial structure and solubility. Partial helical structures of Aβ<SUB>1-40</SUB> induced by low solvent polarity accelerated cytotoxic Aβ<SUB>1-40</SUB> amyloid fibrillation, while predominantly helical folds did not aggregate. Changes in the solvent polarity caused a rapid formation of β-structure-rich protofibrils or oligomers <I>via</I> aggregation-prone helical structures. Modulation of the pH and salt concentration transformed oligomers to protofibrils, which proceeded to amyloid formation. We reveal diverse molecular mechanisms underlying Aβ<SUB>1-40</SUB> aggregation with conceptual energy diagrams and propose that aggregation-prone partial helical structures are key to inducing amyloidogenesis. We demonstrate that context-dependent protein aggregation is comprehensively understood using the macroscopic phase diagram, which provides general insights into differentiation of amyloid formation and phase separation from unfolded and folded structures.</P> [FIG OMISSION]</BR>