• International Journal of CAD/CAM
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• v.8 no.1
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• pp.29-36
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• 2009

Domain mapping is a bijective transformation of one domain to another, usually from a complicated general domain to a chosen convex domain. This is directly useful in many application problems like shape modeling, morphing, texture mapping, shape matching, remeshing, path planning etc. A new approach considering the domain as made up of structural elements, like membranes or trusses, is developed and implemented using the nonlinear finite element formulation. The mapping is performed in two stages, boundary mapping and inside mapping. The boundary of the 3-D domain is mapped to the surface of a convex domain (in this case, a sphere) in the first stage and then the displacement/distortion of this boundary is used as boundary conditions for mapping the interior of the domain in the second stage. This is a general method and it develops a bijective mapping in all cases with judicious choice of material properties and finite element analysis. The consistent global parameterization produced by this method for an arbitrary genus zero closed surface is useful in shape modeling. Results are convincing to accept this finite element structural approach for domain mapping as a good method for many purposes.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.103-112
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• 2017

Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.286-296
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• 1991

The thermodynamic properties of R134a, the prospective R12 alternative, have been computerized using Martin-Hou equation of state and the coefficients given by Willson-Basu. Several experimental results in literatures for PVT data, saturated vapor pressure, saturated liquid density are compared with the calculated results to investigate the accuracy. The average deviation (max. deviation) is 0.13% (0.25%) for saturated liquid density, 0.25% (0.8%) for PVT data. Thermodynamic properties, enthalpy, entropy are compared with the NIST's. The maximum percent difference is 3% for saturated liquid enthalpy, 1.5% for saturated vapor enthalpy, 4% saturated liquid entropy, and 0.7% for saturated vapor entropy. Correction of W-B's coefficients and inclusion of the sixth term of M-H EOS for improvement of accuracy are recommended. R134a and R12 are compared with respect to refrigeration performance. COP's are different from each other within 3%. Refrigeration effect of R134a is superior to that of R12 but refrigeration capacity of R134a is inferior to that of R12 because the volumetric efficiency of the system using R134a is lower than that of the system using R12.

• Journal of the Korean Ceramic Society
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• v.45 no.1
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• pp.1-29
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• 2008

In last two decades, an impressive progress has been recorded in terms of developing new materials or refining existing material composition/microstructure in order to obtain better performance in biomedical applications. The success of such efforts clearly demands better understanding of various concepts, e.g. biocompatibility, host response, cell-biomaterial interaction. In this article, we review the fundamental understanding that is required with respect to biomaterials development, as well as various materials and their properties, which are relevant in applications, such as hard tissue replacement. A major emphasize has been placed to present various design aspects, in terms of materials processing, of ceramics and polymer based biocomposites, Among the bioceramic composites, the research results obtained with Hydroxyapatite (HAp)-based biomaterials with metallic (Ti) or ceramic (Mullite) reinforcements as well as $SiO_2-MgO-Al_2O_3-K_2O-B_2O_3-F$ glass ceramics and stabilized $ZrO_2$ based bioinert ceramics are summarized. The physical as well as tribological properties of Polyethylene (PE) based hybrid biocomposites are discussed to illustrate the concept on how can the physical/wear properties be enhanced along with biocompatibility due to combined addition of bioinert and bioactive ceramic to a bioinert polymeric matrix. The tribological and corrosion properties of some important orthopedic metallic alloys based on Ti or Co-Cr-Mo are also illustrated. At the close, the future perspective on orthopedic biomaterials development and some unresolved issues are presented.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.78-84
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• 2005

Standard crystalline solar cells are generally fabricated with the front grid pattern of silver paste contact. We have reported a detailed theoretical analysis of the proposed segmented cross grid line pattern in this paper. This work was carried out for the optimization of spacing and width of grid finger, main busbar and sub-busbar. The overall electrical and optical losses due to front contact were brought down to $10\%$ or even less as compared to the usual loss of $15\%$ or more in the conventional screen printed silver paste technology by choosing proper grid pattern and optimizing the grid parameters. The total normalized power loss for segmented mesh grid with plated metal contact was also observed and the total power loss could be brought down to $10.04\%$ unlike $11.57\%$ in the case of continuous grid and plated contact. This paper is able to outline the limitations of conventional screen printed contact.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.105-113
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• 2018

Maillard reaction products like melanoidins present in industrial fermentation wastewaters are complex compounds with various functional properties. In this work, novel ultrafiltration (UF) mixed matrix membrane (MMM) composed of polysulfone (PSF) and nanocomposites was prepared through a phase inversion process for the recovery of melanoidins. Nanocomposites were prepared with acid functionalized multiwalled carbon nanotubes (MWCNTs) as the reinforcing filler for chitosan-thermoplastic starch blend. Higher nanocomposites content in the PSF matrix reduced the membrane permeability and melanoidins retention indicating tighter membrane with surface defects. The membrane surface defects could be sealed with dilute polyvinyl alcohol (PVA) solution. The best performing membrane (1% nanocomposites in 18% PSF membrane sealed with 0.25% PVA coating) resulted in uniform melanoidins retention of 98% and permeability of 3.6 L/m2 h bar over a period of 8h. This demonstrates a low fouling PSF membrane for high melanoidins recovery.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.3
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• pp.242-248
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• 2019

Purpose: Severe acute malnutrition (SAM) is an important public health problem which contributes to significant number of under five deaths. Protocol based management significantly decreases risk of deaths in children with medical complications. Methods: Outcome of children aged 2 months-5 years admitted and fulfilling definition of SAM having diarrhea (group A) was compared to children with SAM having medical complications other than diarrhea (group B). Both groups were managed according to standard recommended protocols and monitored and followed up for 12 weeks after discharge. Results: The average weight gain, defaulter rate, primary failure, secondary relapse rate and readmission rate were similar in both groups. Length of stay in group A was three days longer (p-value=0.039). Discharge rate was comparable with overall 68% of children successfully discharged and 50% of children reaching weight/height > -2 standard deviation at follow-up of 12 weeks. Conclusion: The current management protocol is equally effective for managing children with SAM having diarrhea. Good adherence to management protocol of dehydration and timely modification of therapeutic feeds in children with persistent diarrhea results in satisfactory weight gain.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.365-371
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• 2021

In the wake of several high-profile corporate accounting scandals, there has been evidence that companies are more eager to hire Chief Executive Officers (CEOs) with an accounting background. This signals that CEOs with an accounting background are recognized and trusted by the corporate world to boost the quality of financial reporting of a company. If it is so, in the context of combating the earnings management, hiring CEOs with an accounting background (being a conservative accounting practitioner), could become one of the effective internal corporate governance mechanisms (CGM) to bring down the earnings management activities. This study attempts to provide insight into the level of conservatism of the CEO with an accounting background. Following Basu (1997) and Khan and Watt (2009), the firm-year measure of conservatism (C_Score) was obtained, which later was associated with the accounting education of the CEO to determine their relationship. As expected, CEOs with accounting background exhibit a higher level of moral reasoning than their non - accounting educated counterparts. The finding of this study is useful to persuade the policymaker to consider lifting the trend of hiring a CEO with an accounting background as one of the best practices that the companies can work out to lessen earnings management activities.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.1-9
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• 2023

Arsenic (As), which is ubiquitous throughout the environment, represents a major environmental threat at higher concentration and poses a global public health concern in certain geographic areas. Most of the conventional arsenic remediation techniques that are currently in use have certain limitations. This situation necessitates a potential remediation strategy, and in this regard bioremediation technology is increasingly important. Being the oldest representativse of life on Earth, microbes have developed various strategies to cope with hostile environments containing different toxic metals or metalloids including As. Such conditions prompted the evolution of numerous genetic systems that have enabled many microbes to utilize this metalloid in their metabolic activities. Therefore, within a certain scope bacterial isolates could be helpful for sustainable management of As-contamination. Research interest in microbial As(III) oxidation has increased recently, as oxidation of As(III) to less hazardous As(V) is viewed as a strategy to ameliorate its adverse impact. In this review, the novelty of As(III) oxidation is highlighted and the implication of As(III)-oxidizing microbes in environmental management and their prospects are also discussed. Moreover, future exploitation of As(III)-oxidizing bacteria, as potential plant growth-promoting bacteria, may add agronomic importance to their widespread utilization in managing soil quality and yield output of major field crops, in addition to reducing As accumulation and toxicity in crops.

• 한국벤처창업학회:학술대회논문집
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• 2020.11a
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• pp.103-108
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• 2020

본 연구는 미청구공사의 테마감리 지정으로 인해 해당 기업의 보수주의 성향이 증가하였는지 검증한다. 미청구공사에 대한 테마감리 대상지정 배경은 공사 진행률 과대산정 및 평가의 적정성 문제로 회계적 의혹의 적정성에서부터 출발하였다. 미청구공사 금액 계산 시 밀접하게 연관되는 공사진행률은 경영자의 재량적 판단이 반영될 수 있다. 만약 경영자가 이익을 상향할 목적으로 진행률을 부풀린다면 미청구공사가 과다하게 인식되는 문제가 발생한다. 이러한 문제점은 2013년 일부 건설업계의 어닝쇼크를 비롯하여 수주산업에서의 회계부실 문제가 사회적으로 큰 이슈가 되었다. 특히 조선업과 건설업의 잇달은 부실과 함께 미청구공사와 관련된 회계 불투명성이 크게 드러나는 등 회계자료에 대한 불신이 증가되었다. 이로 인해 미청구공사 과대계상 이슈는 금융감독원의 테마감리 대상으로 지정되었다. 본 연구의 실증분석 방법은 2012년부터 2017년까지 Basu(1997)의 보수주의 측정 모형을 이용하여 미청구공사 금액을 반영하기 전과 후를 비교하여 동 기업의 보수주의 회계처리에 미치는 영향을 분석하였다. 중요분석 결과로는 테마감리 지정 이후에 미청구공사에 대한 보수적 회계처리가 유의하게 증가되었다. 이를 통해 테마감리 지정 목적인 미청구공사금액의 과대계상 금지와 공시 강화라는 측면에서 그 실효성을 확인하였다.