• Title, Summary, Keyword: B/C ratio

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Economic Feasibility Analysis for Development of Small Hydropower Using Agricultural Reservoirs (농업용 저수지의 소수력 개발을 위한 경제성 분석)

  • Woo, Jae-Yeoul;Kim, Jin-Soo;Jang, Hoon;Kim, Young-Hyeon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.53 no.2
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    • pp.53-60
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    • 2011
  • This study was conducted to investigate the effect of hydropower factors (watershed, gross head), operation ratio and unit electricity cost on the benefit-cost ratio (B/C ratio) of small hydropower using agricultural reservoirs. The equation of B/C ratio was expressed as a function of watershed area, gross head, operation ratio and unit electricity cost. The benefit increased with watershed area, gross head and unit electricity cost, while the cost increased with watershed area and gross head but decreased with operation ratio. The B/C ratio increased with watershed area, gross head, operation ratio and unit electricity cost. While the effect of gross head on the B/C ratio decreased with watershed area, the effect of operation ratio and unit electricity cost on the B/C ratio increased with watershed area. The operation ratio is an important factor to affect the B/C ratio and therefore we need to develop hydropower for the heightened dams to expect high operation ratio due to continuous water release. The unit electricity cost is also an important factor to affect the B/C ratio and the B/C ratio was always below 1 unless unit electricity cost is over 60 Won/kWh under given conditions. The reservoirs with economic feasibility for small hydropower development were three in 21 when the equation of B/C ratio was appled to the study reservoirs. The results can be used to choose the appropriate reservoir with economic feasibility for development of small hydropower.

An Analysis of the Reinforced Concrete Circular Ring Sector Plates with Arbitrary Boundary Conditions (任意의 境界條件을 갖는 鐵筋콘크리트 扇形板의 解析(II) - 第 2報 鐵筋比 및 邊長比의 影響 -)

  • Jo, Jin-Gu
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.34 no.1
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    • pp.78-86
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    • 1992
  • This paper aims at investigating the effect of steel ratio and the magnitude of edge-ratio on the mechanical characteristics of reinforced concrete ring sector plate. The influence of steel bars was taken into account by coupling stiffness matrix of the steel bar element with that of the concrete plate element without dealing with separate element of steel bar and by establishing the composite stiffness matrix, which leads to the desirable result which does not increase th number of element could be obtained. Through case studies with 6 cases various steel ratios in ring sector plate supported at four edges and 4 cases with different open angles, the influence of the steel ratio was examined. A numerical analysis to find out the effect of the steel ratio d ue to above mentioned cases was carried out by 4 boundary conditions ; all edges clamped (B.C-1), all edges simply supported (B.C-2), curvilinear two edges clamped and other edges free (B.C-3) and curvilinear two edges simply supported and other edges free(B.C-4). The main results obtained are summarized as follows : 1. The effect of steel ratio on the magnitude of lateral deflection and x-directional bending moment at the center of sector plate and the midpoint of outer and inner curvilinear edges is almost the same up to $30^{\circ}$ of open angle. Beyond $30^{\circ}$ of the angle, the larger the angle, the greater the effect of ratio. 2. In design works using balanced steel ratio, the effect of steel bar can be ignored. But for larger open angles, especially greater than $90^{\circ}$, it proves desirable to consider the effect of steel bar. 3. The effect of the arc length of center circle/straight edge on lateral deflection and bending moment is remarkable in B.C-2. For larger open angle, the effect is also noted except for B.C-3 which turn out hardly affected. 4. The effect of the radius of curvature/straight side length on lateral deflection and x-directional bending moment is noted in B.C-2. As open angle increases, B.C-1 and B.C-3 almost agree and B.C-2 approaches B.C-4.

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Thermal and Mechanical Properties of ZrB2-SiC Ceramics Fabricated by Hot Pressing with Change in Ratio of Submicron to Nano Size of SiC (서브마이크론/나노 크기의 SiC 비율변화에 따른 ZrB2-SiC 세라믹스의 열적, 기계적 특성)

  • Kim, Seongwon;Chae, Jung-Min;Lee, Sung-Min;Oh, Yoon-Suk;Kim, Hyung-Tae
    • Journal of the Korean Ceramic Society
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    • v.50 no.6
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    • pp.410-415
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    • 2013
  • $ZrB_2$-SiC ceramics are fabricated via hot pressing with different ratios of submicron or nano-sized SiC in a $ZrB_2$-20 vol%SiC system, in order to examine the effect of the SiC size ratio on the microstructures and physical properties, such as thermal conductivity, hardness, and flexural strength, of $ZrB_2$-SiC ceramics. Five different $ZrB_2$-SiC ceramics ($ZrB_2$-20 vol%[(1-x)SiC + xnanoSiC] where x = 0.0, 0.2, 0.5, 0.8, 1.0) are prepared in this study. The mean SiC particle sizes in the sintered bodies are highly dependent on the ratio of nano-sized SiC. The thermal conductivities of the $ZrB_2$-SiC ceramics increase with the ratio of nano-sized SiC, which is consistent with the percolation behavior. In addition, the $ZrB_2$-SiC ceramics with smaller mean SiC particle sizes exhibit enhanced mechanical properties, such as hardness and flexural strength, which can be explained using the Hall-Petch relation.

Investment Beneficial Analysis of Culture of Mountain Medical Plant Resources - Open field Culture of Schizandra - (산지약용식물자원의 재배 투자 수익성 분석 - 오미자 노지재배 -)

  • Park, Yong-Bae;Kim, Jae-Sung;Kim, Ki-Dong
    • Journal of Korean Society of Forest Science
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    • v.99 no.6
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    • pp.808-815
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    • 2010
  • This study is to give informations about management Situations and investment returns to someone who will newly cultivate schizandra or expand area of culture. This study used IRR, B/C Ratio and NPV for beneficial analysis. We surveyed fifty one among schizandra cultivation farmhouses in chief producing districts Gangwon Inje, Gyeongbuk Munkyung, Kyungnam Sancheong and Jeonnam Whasoon in Korea from May till September in 2009. So this study surveyed about inputted labors and materials, land price and etc. by working process to calculate producing and operating cost. Fruits of schizandra are sold from 5,000 won to 6,000 won per kg at locals. And IRR(Internal Rate of Returns), B/C Ratio and incomes ratio is calculated by three senarios 5,000 won, 5,500 won and 6,000 won per kg at locals. Discount rate is 3.00%. As the result of this study IRRs are -16.00%, -6.91%, 0.40% one after another and B/C Ratios are 0.81, 0.89, 0.97 one after another. And schizandra cultivation isn't profitable. When price of schizandra fruits is 6,200 won per kg, IRR is 3.00% and B/C Ratio is 1.00. Therefore, if price of schizandra fruits is over 6,200 won per kg, we judge that it is profitable. And income ratio is 23.9% on 6,200 won per kg.

A Case Study of Hospital Business Analysis (병원경영분석에 관한 사례연구)

  • Lee, Eun-Hyung;Jung, Key-Sun;Do, Key-Hyun;Kim, Young-Bae
    • Korea Journal of Hospital Management
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    • v.17 no.1
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    • pp.79-112
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    • 2012
  • The purpose of this study is to examine the differences of profitability based on the analysis of business and medical service performances of four hospitals in Incheon area with similar size. and to compare hospitals with the best and the worst performances and analyze the factors behind the differences. The differences could be caused by differences in medical service statistics, number of staff, and financial results, etc. The data was acquired through the homepage of the National Tax Service(financial statements for the fiscal year 2009) and the Medical Record Association of Incheon(medical service statistics for the years 2008 and 2009) along with questionnaire survey to the hospitals(personnel data for the year 2009). The results of the study are as follows. Medical profits to medical revenues ratio for the hospitals(referred as Hospital A, B, C, and D) shows, in order, C(8.2%), A(8.0%), B(7.8%), and D(7.4%). However, net income to medical revenues ratio shows otherwise: C(8.5%), D(5.8%), A(3.0%), and B(0.6%). Hospital B shows a high medical profit to revenue ratio but the lowest net income to revenue ratio due to large interest expenses. The leverage ratio of Hospital B is the highest (419.6%), resulting in a very low interest coverage ratio(1.1). On the other hand, Hospital C shows favorable results in both profit ratios, with 8.2% and 8.5% each. Hospital C has the lowest leverage ratio(53.0%) and the highest interest coverage ratio(34.9). Therefore, the results show Hospital C has the best performance while Hospital B the worst. The two hospitals(B and C) show similar results in certain areas and big differences in other areas. The area that has the biggest influence on financial results turns out leverage ratio. Hospital B shows 'very good' to 'good' results in terms of medical service statistics in general. However, the leverage ratio is too high and the liquidity ratio too low, resulting in a very low profit ratio. The results of this study have some limitations in terms of generalization as only four hospitals in Incheon area were selected for the study, resulting in a deficiency in the representativeness of the sample. Further studies with bigger sample size and deeper analysis are expected in this area.

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Molecular Analysis of Spontaneous Mutations in erm(A) and erm(C) Selected In vitro as a Constitutive MLS$_B$ Resistant Staphylococci (MLS$_B$계 항생물질 유도 내성 세균에서 In vitro로 선발된 지속성 내성형 erm(A)와 erm(C)의 분자적 특성 규명)

  • Yoon, Eun-Jeong;Jin, Sung-Hye;Choi, Eung-Chil;Shim, Mi-Ja
    • YAKHAK HOEJI
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    • v.51 no.2
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    • pp.108-114
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    • 2007
  • The predominant Macrolides-Lincosamide-Streptogramin B (MLS$_B$) antibiotics resistance genes in staphylococci are erm(A) and erm(C). There is the phenomenon that the ratio of constitutively MLS$_B$ antibiotics resistance (cMLS) in erm(A) is much higher than in erm(C). Thus, we confirmed that the difference of the mutation ratio between erm(A) and erm(C) makes the phenomenon. We examined 8 staphylococci carrying inducibly expressed (iMLS) erm(A) or erm(C) genes. After overnight incubation in the presence of the non-inducer MLS$_B$ antibiotics, spontaneous mutants constitutively expressed MLS$_B$ resistance were selected. Against our expectation, the mutation ratio of erm(A) was lower than erm(C). Therefore, possibilities of other factors determining the ratio of cMLS phenotype might be concerned. All the mutants showed sequence alterations in translational attenuator and all the alterations seemed to give rise to change the second structure of mRNA to express constitutively. For erm(A), 4 different types of sequence deletions ranging from 72 bp to 122 bp and 3 different types of duplications ranging 24 bp to 93 bp were detected. Also, there were 9 different types of duplications ranging 15bp to 154bp in erm(C).

Fatty Acid Composition of Korean Pumpkins (한국 호박의 지방산 조성)

  • 남현근;고대희
    • The Korean Journal of Food And Nutrition
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    • v.7 no.2
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    • pp.95-99
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    • 1994
  • In order to investigate the fatty acid composition of Korean pumpkins, this study was designed. Three samples of Korean pumpkins, A(yellowish ripe), B(unripe, 30 days old) and C(unripe, 20 days old) were used for fatty acid analysis by gas chromatography. The results were as follows : Pumkin C, B and A showed 10, 12 and 15 kinds of fatty acids, respectively. In case of palmitic acid(C16:0), pumpkin C, B and A showed 22.5%, 22.9% and 26.6%, respectively. In case of u linolenic acid(C18:3), pumpkin C, B and A showed 22.6%, 23.6% and 44.8%, respectively. In case of palmitoleic acid(Cl6:1), pumpkin C. B and A showed 12.4%, 10.1% and 0.5%, respectively. In case of oleic acid(C18:1), pumpkin C. B and A showed 9.2%, 7.7% and 2.8%, respectively, In case of stearic acid(C18:0), pumpkin C, B and A showed B.S%, 3.7% and 3.5%, respectively. The ratio of P/S was 1.4, 1.6 and 1.9 for sample C, B and A, respectively. The ratio of w-3/w-6 was 1.1, 0.9 and 2.6 for sample C, B and A, respectively. Through this study, the ripe pumpkin(sample A) was thought to be good enough in nutritional aspects of fatty acids, particularly a-linoleic acid, Cl8 : 3(u-3) series.

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Effects of DC Substrate Bias Power Sources and Reactant Gas Ratio on Synthesis and Tribological Properties of Ternary B-C-N Coatings (기판 바이어스 DC 전원의 종류와 반응가스 분압비가 3성분계 B-C-N 코팅막의 합성과 마찰 특성에 미치는 영향)

  • Jeong, Da-Woon;Kim, Doo-In;Kim, Kwang-Ho
    • Journal of the Korean institute of surface engineering
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    • v.44 no.2
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    • pp.60-67
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    • 2011
  • Ternary B-C-N coatings were deposited on Si(100) wafer substrate from $B_4C$ target by RF magnetron sputtering technique in $Ar+N_2+CH_4$ gas mixture. In this work, the effect of reactant gas ratio, $CH_4/(N_2+CH_4)$ on the composition, kinds and amounts of bonding states comprising B-C-N coatings were investigated using two different bias power sources of continuous and unipolar DCs. In addition, the tribological properties of coatings were studied with the composition and bonding state of coating. It was found that the substrate bias power had an effect on chemical composition, and all of the obtained coatings were nearly amorphous. Main bonding states of coatings were revealed from FTIR analyses to be h-BN, C-C, C-N, and B-C. The amount of C-C bonging mainly increased with increase of the reactant gas ratio. From our studies, both C-C and h-BN bonding states improved the tribological properties but B-C one was found to be harmful on those. The best coating from tribological points of view was found to be $BC_{1.9}N_{2.3}$ composition.

Study on the fabrication and the growth mechanism of Bi-2223 superconducting phase by diffusion method (확산법에 의한 Bi-2223 초전도상의 제조 및 성장기구에 관한 연구)

  • 최성환;최효상;한태희;황종선;한병성
    • Electrical & Electronic Materials
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    • v.7 no.4
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    • pp.281-288
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    • 1994
  • According to spread volume of B(BiPbCuO) layer, composition ratio and each stage of sintering process, we studied stability of high Tc superconductor phase and generation and growth movement of superconducting phase. The dual layer composed of SrCaCuO and BiPbCuO compound were prepared to develop the Bi-2223 superconductor[108K] through interaction and diffusion during sintering process. The dual layer samples were sintered at 830.deg. C for 0-210 hours. From the result, the optimum conditions were : spread volume(A:B=1:0.6), sintering time(210h) and composition ratio(A:S $r_{2}$C $a_{2}$C $u_{2}$- $O_{x}$, B:B $i_{1.9}$P $b_{0.5}$C $u_{3}$ $O_{y}$) at 830.deg. C.. C.C.C.

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Rheological Evaluation of Cooked Rice with Milk (우유첨가 취반미의 물성에 관한 연구)

  • 김경자;강선희;곽연주
    • Korean journal of food and cookery science
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    • v.7 no.4
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    • pp.71-86
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    • 1991
  • This study was attempted to enhance nutritional value of cooked rice by adding milk in cooking water. Cooked and soaked rice with five different levels of milk in cooking water (0%, A: 30%, B: 50%, C: 70%, D: 100%, E) was tested for rheological parameters, fine structural changes, sensory evaluation. 1. Water absorbance of raw rice in cooking water with varying amountes of milk, was tested at $5^{\circ}C$ and $15^{\circ}C$ for 2 hours. Water absorption ratio was decreased as milk content was increased and soaking temperature was low. Time for maximum water absorption of sample A was 40 min at 1$15^{\circ}C$ but for sample B to D, it was not reached until 120 min. 2. Electronmicroscopic observation revealed that starch granules of rice lost their regular forms by soaking for 90 minutes, but recovered most of initial regularity after 24 hours. Increase in milk content of soaking water decreased marginal sharpness of the starch granule, presumably due to reduced swelling of the granule. 3. Degree of gelatinization of cooked rice was highest in sample A and progressively decreased as milk content was increased. It was, however, increased in all samples when the cooking water to rice ratio was raised from 160% to 180%. During 4 hour storage, rates of retrogradation were not different between A and B samples, but those of C, D and E were about 2.5 times higher than A and B under the optimal condition of 170% cooking water to rice ratio. This was in the order reverse to hardness order of AC>A, D>E at cooking water to rice ratios of 160% and 170%, above which A sample surpassed the rest of samples. 4. Sensory evaluation conducted by fifteen university students as panelists showed that there were more significant differences among five samples in flavour, texture than appearance and a notable preference for b and C over A, D and E.

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