• Korean Chemical Engineering Research
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• 제47권1호
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• pp.127-132
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• 2009

석유를 대체할 수 있는 현실적 대안으로 주목받고 있는 직접석탄액화(direct coal liquefaction, DCL) 공정의 경제성을 평가하고자하였다. 이때 역청탄을 이용하여 주요 제품(디젤, 나프타) 생산량 50,000 bbl/day의 규모에 대하여 각 공정에 적합한 검토기준을 세워 비용 및 매출액등을 산정하였다. 또한 각 공정별 민감도 분석을 실시하여 공정에 대한 중요 변수들의 가격 변동에 따른 경제성을 평가하였다. 본 생산량을 기준으로 Illinois #6 유연탄을 원료탄으로 사용하였을 때, 총 투자액은 $3,994,858,000로 나타났다. 내부수익률(internal rate of return, IRR)의 경우, 기본조건에서 각각 6.60%로 나타났으며, 원료석탄 가격과 생산 제품 판매가에 가장 크게 영향을 받는 것으로 나타났다. 원금상환 기간은 12.8년으로 긴 시간을 요구하며, 이는 현재의 고석탄가 때문으로 해석된다. 또한 민감도 분석 결과 제품가격, 원료석탄 가격, 건설비의 변동률 순서로 수익률에 변화를 주는 것으로 나타났다.

• 한국가금학회지
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• 제39권1호
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• pp.53-62
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• 2012

In the past, poultry nutrition has focussed on increasing the production efficiency to meet the progress achieved in the genetic potential of broilers and layers. Future directions in poultry nutrition will be driven by not only by the need to maximise biological and economic performance of birds, but also by societal issues (environment, antibiotic growth promoters, welfare, traceability and use of genetically modified ingredients). Key advances in poultry nutrition are discussed and future directions, which can be expected, are highlighted. Given the tightening supply and ever-increasing cost of raw materials, there will be more pressure to extract every unit of energy and nutrients from feed ingredients. In this context, a number of feed additives are expected to play an increasingly significant role. Feed enzymes and crystalline amino acids, in particular, will have a profound effect on future sustainability of the poultry industry. Future nutritional research need to focus on identifying the barriers to effective digestion and utilisation of nutrients and, to achieve this objective, nutritionists must combine their expertise with those of specialising in other biological sciences, including immunology, microbiology, histology and molecular biology.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.120-128
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• 2015

In this paper, Residential roof top photovoltaic system with 9.9 kW design is proposed. The system composed of 200 Watts solar array 33 panels connecting in series 10 strings and parallels 3 strings which have maximum voltage and current are 350 V and 23.8 A. The 10 kW sinusoidal grid-connected inverter with window voltage about 270-350 is selected to convert and transfer DC Power to AC Power at PCC (Point of Common Coupling) of power system following to utility standard. However the impact of fluctuation and uncertainty of weather condition of PV may decrease the voltage stability and voltage collapse of power system. In order to solve this problem the energy storage such 120 V 1200 Ah battery bank and 30 kVAR capacitor are designed for voltage stability control. The other expensed for installing the system such battery charger, cable, accessories and maintenance cost are concerned. The economic analysis by using investment from money loan with interest about 7% and use own money which loss income of deposit about 3% are calculated as 671,844 and 547,044 for PV system with energy storage and non energy storage respectively. The solar energy from PV is about 101,616 Bath per year which evaluated by using the value of $5kWh/m^2/day$ from average peak sun hour (PSH) of the Thailand and 6.96 Bath/kWh of Feed in Tariff Incentive. The payback periods of four scenarios are proposed follow as i) PV system with energy storage and use loan money is 15 years ii) PV system with no energy storage and use loan money is 10 years iii) PV system with energy storage and use deposit money is 9 years iv) PV system with energy storage and use deposit money is 7 years. In addition, the other scenarios of economic analysis such no FIT support and other type of economic analysis such NPV and IRR are proposed in this paper.

• 청정기술
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• 제29권1호
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• pp.53-58
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• 2023

This study shows the summary of the economic performance of excess electricity conversion to hydrogen as well as methane and returned conversion to electricity using a fuel cell. The methane production process has been examined in a previous study. Here, this study focuses on the conversion of methane to electricity. As a part of this study, capital expenditure (CAPEX) is estimated under various sized plants (0.3, 3, 9, and 30 MW). The study shows a method for economic optimization of electricity generation using a fuel cell. The CAPEX and operating expenditure (OPEX) as well as the feed cost are used to calculate the discounted cash flow. Then the levelized cost of returned electricity (LCORE) is estimated from the discounted cash flow. This study found the LCORE value was ¢10.2/kWh electricity when a 9 MW electricity generating fuel cell was used. A methane production plant size of 1,500 Nm³/hr, a methane production cost of $11.47/mcf, a storage cost of $1/mcf, and a fuel cell efficiency of 54% were used as a baseline. A sensitivity analysis was performed by varying the storage cost, fuel cell efficiency, and excess electricity cost by ±20%, and fuel cell efficiency was found as the most dominating parameter in terms of the LCORE sensitivity. Therefore, for the best cost-performance, fuel cell manufacturing and efficiency need to be carefully evaluated. This study provides a general guideline for cost performance comparison with LCORE.

• Animal Bioscience
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• 제36권6호
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• pp.929-942
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• 2023

Objective: This study was conducted to evaluate the effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, pork quality, pork flavor, and economic benefit in growing and finishing pigs. Methods: A total of 140 growing pigs ([Yorkshire×Landrace]×Duroc) were assigned to five treatments considering sex and initial body weight (BW) in 4 replications with 7 pigs per pen in a randomized complete block design. The experimental diets included a corn-soybean meal-based basal diet with or without 0.05% or 0.1% β-glucan and 0.02% vitamin E. The pigs were fed the diets for 12 weeks (phase I, 0 to 3; phase II, 3 to 6; phase III, 6 to 9; phase IV, 9 to 12). The BW and feed intake were measured at the end of each phase. Blood samples were collected at the end of each phase. Four pigs from each treatment were selected and slaughtered for meat quality. Economic benefit was calculated considering the total feed intake and feed price. Pork flavor was analyzed through inosine monophosphate analysis. Results: The average daily gain and feed efficiency were improved compared to the control when β-glucan or vitamin E was added. Supplementing 0.05% β-glucan significantly increased the lymphocyte concentration compared to the addition of 0.1% β-glucan and the content of vitamin E in the blood increased when 0.02% vitamin E was added. The treatment with 0.1% β-glucan and 0.02% vitamin E showed the most economic effect because it had the shortest days to market weight and the lowest total feed cost. The addition of β-glucan or vitamin E had a positive role in improving the flavor of pork when considering that the content of inosine monophosphate was increased. However, carcass traits and meat quality were not affected by β-glucan or vitamin E. Conclusion: The addition of 0.1% β-glucan with 0.02% vitamin E in growing and finishing pig diets showed great growth performance and economic effects by supplying vitamin E efficiently and by improving the health condition of pigs due to β-glucan.

• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.187-191
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• 2017

Objective: An experiment was conducted to examine the effect of dietary supplementation of dried and ground foliage of black gram (Vigna mungo L.) on feed intake and utilization, and production performance of crossbred lactating cows. Methods: Eighteen lactating crossbred (Bos taurus${\times}$Bos indicus) cows (body weight $330.93{\pm}10.82kg$) at their second and mid lactation (milk yield $6.77{\pm}0.54kg/d$) were randomly divided into three groups of six each in a completely randomized block design. Three supplements were formulated by quantitatively replacing 0, 50, and 100 per cent of dietary wheat bran of concentrate mixture with dried and ground foliage of black gram. The designated supplement was fed to each group with basal diet of rice straw (ad libitum) to meet the requirements for maintenance and milk production. Daily feed intake and milk yield was recorded. A digestion trial was conducted to determine the total tract digestibility of various nutrients. Results: The daily feed intake was increased (p<0.05) with the supplementation of black gram foliage. Although the digestibility of dry matter, organic matter, crude protein, and ether extract did not vary (p>0.05), the fibre digestibility was increased (p<0.05), which ultimately improved (p<0.05) the total digestible nutrients content of composite diet. Although, the average milk yield (kg/animal/d) and composition did not differ (p>0.05) among the groups, milk yield was increased by 10 per cent with total replacement of wheat bran in concentrate mixture with of black gram foliage. The economics of milk production calculated as feed cost per kg milk yield (INR 10.61 vs 7.98) was reduced by complete replacement of wheat bran with black gram foliage. Conclusion: Black gram foliage could be used as complete replacement for wheat bran in concentrate mixture of dairy cows in formulating least cost ration for economic milk production in small holders' animal production.

• Asian-Australasian Journal of Animal Sciences
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• 제21권6호
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• pp.769-775
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• 2008

This study was on the relative net income (RNI) for 18,286 Iranian Holstein cows from 799 herds, with first freshening between 1991 and 2000. Two kinds of production system, which differed mainly in milk pricing system and feed cost, were considered. Four different models adopted from the literature were examined to find the optimum model. They differed by the cost of rearing and growth after first calving and they needed different amounts of economic data at the farm level. Results showed that four measures of RNI were highly correlated (>0.96) and could be used equally to measure lifetime profitability of cows. Therefore, in herds without a regular system for recording economic and management data, use of the simplest model is recommended. Multiple regression analysis revealed that RNI was affected by age at first freshening, milk yield and days of productive life (DPL), regardless of production system, and a similar breeding goal could be defined for the two systems. Multiple regression analysis of RNI showed that in order to obtain an unbiased estimate of economic value for DPL, the per day milk yield, not total lifetime milk yield, should be included in the regression model along with DPL. Regression analysis suggested that it is possible to predict RNI using information on age at first freshening along with the length of first lactation and per day milk yield with a coefficient of determination ranging from 0.44 to 0.47.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.86-90
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• 2006

This study was carried out to determine the effects of free choice feeding of starter feed and whole cereals on the growth of turkey poults. Two hundred-seventy poults (7-d old) were divided into 3 treatment groups each with 3 replications containing 15 males and 15 females. Control poults (C) were fed only on starter feed (280 g CP and 11.7 MJ ME/kg). Treatments for choice-fed turkey poults were offered a choice of a starter feed and wheat (120 g CP and 12.3 MJ ME/kg) for wheat selecting (WS) or maize (83 g CP and 13.9 MJ ME/kg) for maize selecting (MS) group in separate feeders. Final live weight (2,280.7 g for the C vs. 2,374.3 and 2,324.6 g for the WS and MS), daily gain (39.21 g vs. 40.87 and 39.99 g) and total feed intake (95.2 g vs. 103.2 and 97.9 g) in the WS poults were significantly higher (p<0.05) than those of the C group, but feed conversion ratio was not significantly different between the treatments. The proportional intakes of cereals vs. total feed intake were 11% in both the WS and MS group. The amount of protein intake in the C group (280 g CP/kg diet) was significantly (p<0.05) higher than that in WS and MS groups (263 and 259 g CP/kg diet, respectively) whilst the ME intake in the C group (11.7 MJ/kg diet) was significantly (p<0.05) lower than that in MS group (11.9 MJ/kg diet). Our results showed that turkey poults fed starter feed and whole wheat in a free choice feeding system have a higher efficiency in terms of daily gain, final live weight, and an economic advantage may be obtained from free choice feeding due to a reduced protein intake and feed cost.

• 한국기후변화학회지
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• 제1권2호
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• pp.163-177
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• 2010

본 논문은 1,185세대가 거주하고 있는 공동주택을 대상지로 하여 정부지원제도인 '태양광주택보급사업'과 '발전차액지원제도'를 각각 활용하여 PV 시스템 도입을 도입할 경우의 경제성을 비교 분석하였다. 각 시나리오별 분석 결과, 수익으로 전력판매수익 만을 고려한 경우, NPV가 보조금 지원제도는 -560백만원으로 분석되었고, 발전차액지원제도는 -87백만원으로 분석되었다. 전력판매수익과 온실가스 배출권 수익을 함께 고려한 경우에도 NPV가 보조금 지원제도는 -530백만원으로 분석되었고, 발전차액지원제도는 -57백만원으로 분석되어 모두 수익성이 없는 사업으로 나타났다. PV 시스템 도입으로 인해 회피되는 대기오염물질로 인한 사회적 편익을 함께 분석한 결과도 그 편익이 미미하여 여전히 경제성이 없는 것으로 평가된다. 할인율과 초기비용의 변동을 기준으로 민감도 분석을 한 경우, 보조금 지원제도의 경우에는 할인율을 3%까지 낮추고, 초기 설비 투자 비용을 정부 제시기준 단가인 721만원/kW에서 650만원/kW로 낮춘 것에 배출권 수익까지 포함한 경우에도 여전히 사업성이 없는 사업으로 나타났지만, 발전차액 지원 제도의 경우에는 배출권 수익을 포함하지 않고도 할인율 약 7.2%와 초기 설비투자비용 684만원/kW에서 각각 손익분기점이 되면서 수익성이 있는 사업으로 전환되어 발전차액지원제도가 PV 시스템 도입에 훨씬 유리한 것으로 나타났다. 사회적 비용을 고려한 경우에는 보조금제도를 활용한 모든 시나리오는 배출권 수익과 환경편익을 모두 포함하여도 수익성이 없는 사업으로 나타났으나, 발전차액지원제도를 활용한 시나리오의 경우에는 배출권 수입을 제외하고도 할인율 7.2%와 초기비용 686만원/kW가 각각 손익분기점이 되면서 수익성이 있는 사업으로 전환되었다. 본 연구의 결과, 할인율이 7.2% 이하가 되든지 초기 설비투자비용이 정부 제시 기준 단가보다 4.9% 낮아진다면 발전차액지원제도 하에서도 공동주택의 태양광발전시스템이 경제성을 갖는 것으로 분석되었다. 우리나라의 높은 아파트 보급률과 PV 시스템 도입으로 발생하는 긍정적인 사회적 환경적 편익을 고려하면 공동주택의 태양광 시설 설치에 대해 발전차액지원제도를 확대 지원함으로써 화석연료의 사용을 절감하고, 온실가스 배출을 줄여서 에너지자급도 제고와 기후변화에 대한 대응을 통해 녹색성장에 기여할 수 있을 것으로 생각된다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권9호
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• pp.1205-1212
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• 2010

The aim of the present study was to evaluate the effects of replacing 70% of the protein from fish meal by protein from ensiled or dry cassava leaves and sweet potato vines on the performance and carcass characters of growing F1 (Large White${\times}$Mong Cai) pigs in Central Vietnam. Twenty-five crossbred pigs (Large White${\times}$Mong Cai) with an initial weight of 19.7 kg (SD = 0.84) were allocated randomly to five treatment groups with 5 animals per group (3 males and 2 females). Pigs were kept individually in pens ($2.0{\times}0.8\;m$) and fed one of five diets over 90 days. The control diet was formulated with fish meal (FM) as the protein source while the other four diets were formulated by replacing 70% of fish meal protein by protein from ensiled cassava leaves (ECL), dry cassava leaves (DCL), dry sweet potato vines (DSPV) or ensiled sweet potato vines (ESPV). Animals were fed their diets at 4% of BW. Results showed that final BW, ADG, DMI and feed conversion ratio (FCR) among the experimental treatments were not significantly different (p>0.05). ECL or DCL and ESPV reduced feed cost per unit gain by 8-17.5% compared to the fish meal diet. There were no significant differences in carcass characters among the diets (p>0.05). Lean meat percentages and protein deposition ranged 41.5-45.8% and 40.2-52.9 g/d, respectively. Using ensiled or dry cassava leaves and sweet potato vine can replace at least 70% of the protein from fish meal (or 35% of total diet CP) without significant effects on performance and carcass traits of growing (20-65 kg) pigs. Including cassava leaves and sweet potato vines could improve feed cost and therefore has economic benefits.