• Title/Summary/Keyword: average density

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Understanding the seasonal status of fisheries resource in the East China Sea by using bottom trawl (저층트롤을 이용한 동중국해 해역의 계절별 수산자원 현황)

  • Hyoung-Ho SHIN;Jungkwan LEE;Geunchang PARK;Byeong Gwon LIM;Doo Jin HWANG;Kyounghoon LEE
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.59 no.3
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    • pp.231-241
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    • 2023
  • This study was investigated in order to find composition and density of fisheries resource using bottom trawl in April, July, August, and November 2022 in the East China Sea. The average density of fisheries resource was estimated using the swept area method. As a result, 35 species were collected from the East China Sea. These included 21 fishes, six crustaceans, six cephalopods and two echinoderms. Seasonally, the average density of crustacean individuals per unit area were highest in November (692.1 inds./km2), while cephalopod individuals per unit area were highest in August (39.4 inds./km2). The average density of fish individuals per unit area were highest in August at 355.0 (inds./km2).

An Experimental Study on the Characteristics of Moxa Combustion (II) - On the Density of Moxa Material - (애구(艾灸)의 연소(燃燒) 특성(特性)에 관한 실험적(實驗的) 연구(硏究)(II) - 애주(艾炷)의 밀도(密度)를 중심(中心)으로 -)

  • Park, Young-Bae;Kang, Sung-Keel;Huh, Wung
    • Journal of The Association for Neo Medicine
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    • v.1 no.1
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    • pp.103-113
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    • 1996
  • It is thought that the quantity and quality of the heat stimulation and the mechanism of heating process are important to understand the moxa-combustion. In order to get the basic data on the effective moxa-combustion method, combustion temperature changes (average temperature, peak temperature, average gradient temperature and maximum gradient temperature) of the heating period were measured respectively by the density of moxa material. For the experiment, samples of $300mg/0.26cm^3$ , $400mg/0.26cm^3$ and $500mg/0.26cm^3$ of moxa material were molded in a conical mold with each 10mm in diameter and height. 1. The average temperature and peak temperature of heating period on the moxa-combustion showed higher in the $400mg/0.26cm^3$ and $300mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. 2. The average gradient temperature of heating period on the moxa-combustion rose quickly in the $300mg/0.26cm^3$, $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in that order and the maximum gradient temperature rose more quickly in the $300mg/0.26cm^3$ and $400mg/0.26cm^3$ than in the $500mg/0.26cm^3$ sample respectively. According to the above results, it is concluded that the density of moxa material is (the) more important (factor) than the weight or volume of moxa material on the combustion temperature changes of the heating period for the evaluation of the quality and quantity of moxa-combustion.

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Infection Status with the Metacercariae of Heterophyid Trematode in Mullet and Goby Collected from Western Coastal Areas of Cholla-do, Korea

  • Sohn, Woon-Mok;Moon, Byung-Chul
    • Biomedical Science Letters
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    • v.7 no.1
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    • pp.31-37
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    • 2001
  • The present study was performed to investigate the infection status of heterophyid fluke metacercariae in mullets and gobies collected from some coastal areas of cholla-do. The collected fishes were transferred to the laboratory, artificially digested with pepsin-HCI solution and examined under a stereomicroscope. In 70 mullets examined, the metacercariae of Heterophyes nocens (in 28.6% of fish), Heterophyopsis continua (in 2.9%), Pygidiopsis summa (in 32.9%) and Stictodora spp. (in 14.3%) were detected. The metacercariae of H nocens were detected in mullets from Shinan-gun (in 60.0% of fish), Muan-gun (in 54.4%), Hampyong-gun (in 25.0%) and Yonggwang-gun (in 16.7%). The average metacercarial density per infected fish were 7.6,34, 10 and 5 in each areas. A total of 7 metacercariae of H. continua was detected in only 2 mullets from Hampyong-gun. The metacercariae of p. summa were detected in mullets from Haenam-gun (in 80.0% offish), Muan-gun (in 27.3%), Hampyong-gun (in 16.7%) and Puan-gun (in 100%). The average metacercarial density per infected fish were 350, 14, 5 and 97 in each areas. The metacercariae of Stictodora spp. were detected in mullets from Shinan-gun (in 26.7% offish), Hampyong-gun (in 33.3%) and Puan-gun (in 20.0%). The average metacercarial density per infected fish were 2.8, 18.8 and 2.5 in each areas. In 70 gobies examined, the Metacercariae of H nocens (in 15.7% of fish), H continua (in 47.1%) and Stictodora spp. (in 48.6%) were detected. The metacercariae of H. nocens were detected in gobies from Shinan-gun (in 50.0% of fish) and Yonggwang-gun (in 10.0%). The average metacercarial density per infected fish were 71 and 2 in each areas. The metacercariae of H. continua were detected in gobies from Shinan-gun (in 65.0% of fish), Hampyong-gun (in 70.0%) and Yonggwang-gun (in 60.0%). The average metacercarial density per infected fish were 5.7,6.6 and 3.2 in each areas. The metacercariae of Stictodora spp. were detected in gobies from Shinan-gun (in 80.0% offish), Hampyong-gun (in 70.0%) and Puan-gun (in 40.0%). The average metacercarial density per infected fish were 149,203 and 5.5 in each areas. From the above results, it was confirmed that the mullet and goby from some coastal areas of cholla-do are infected with numerous metacercariae of heterophyid trematodes.

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A Study on the Reliability Index and Customer Density of Distribution System (배전계통의 신뢰도 지수와 수용가 밀도에 관한 연구)

  • Bae, In-Su;Kim, Jin-O
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.9
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    • pp.1646-1650
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    • 2011
  • SAIDI(System Average Interruption Duration Index) is the index that signifies the power quality of customers. SAIDI is also used to know how well utilities operate their systems. The annual interruption time in the areas that consists of widely distributed customers, is generally longer than that in the areas that consists of heavily concentrated customers. The Reliability index of huge system is not necessarily better or worse than that of small system, because SAIDI is irrelevant to the total amount of power sold or the total number of customers. This paper proposes a customer density very relevant to SAIDI. The proposed customer density is used to modify the existing SAIDI to more clearly express the service level of power supply. A modified WSAIDI(weighted SAIDI) can be a useful indicator helping utilities improve the reliability of their systems and customers evaluate the service level of receiving power.

Prediction of MCFC Performance Using Three Dimensional Heat and fluid Flow Analysis with Electrochemical Reaction (전기 화학 반응을 포함한 3차원 열유동 해석을 이용한 용융탄산염 연료전지의 성능예측)

  • Cho H. M.;Lee K. W.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.219-224
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    • 2003
  • An analysis procedure for the MCFC channel flow has been developed to predict the fuel cell performance. As for the electrochemical reaction, among several chemical reaction models, one that fits the data best is adopted after a comprehensive comparative study. The Wavier-Stokes, energy, and species equations are solved to obtain the velocity, temperature and concentration fields for a specified average current density. The procedure is iterative as the local current density, or the reaction rate, is allowed to vary with the gas composition. A series of calculations are then carried out to examine the effects of gas flow rate, gas composition, gas usage rate, inlet gas temperature, and average current density on the fuel cell performance. The fuel cell characteristics, such as the temperature, current density distributions, and the concentration fields, for various operating conditions are presented and discussed.

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The Correlation among Growth Development, Bone Mineral Density of Carpus and Nutrient Intakes in Preschool Children (미취학 아동에 있어 신체발달, 손목 골밀도 및 영양섭취와의 상관성)

  • 명금희;나현주;최미경;김애정
    • Journal of the East Asian Society of Dietary Life
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    • v.14 no.2
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    • pp.113-122
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    • 2004
  • This study was conducted to examine the correlation among growth development, bone mineral density, and nutrient intakes in preschool children. A total of 62 preschool children measured the anthropometric characteristics and the bone mineral density of carpus using DEXA. The questionnaires categorized to determine health status, life style, dietary behaviors, and dietary intakes were filled out by children's mothers. The average ages of the study subjects were 62.4 months in boys and 62.1 months in girls. The birth height and weight of the subjects were 50.9 cm and 3.4 kg in boys and 50.3 cm and 3.3 kg in girls, respectively. The average height, weight, % body fat, and obesity index were 111.7 cm, 19.6 kg, 15.0%, -2.1% in boys and 109.4 cm, 18.7 kg, 17.5%, 0.2% in girls, respectively. The bone mineral density in carpus was 0.25 g/cm$^2$ in boys and 0.24 g/cm$^2$. In girls. Proportions of children having regular meals were 69.0%, 94.7%, and 69.0% for breakfast, lunch, and dinner, respectively. The major reasons for irregular meal were poor appetite and lack of time for breakfast and snacks for dinner. Most of the children(52.6%) had breakfast with the whole family together, and all the children had lunch and dinner with a part of the family. Most of the children answered they had snack more than once a day, and 64.3% had an unbalanced diet. The intakes of energy, calcium, iron, zinc, vitamin A, vitamin B$_1$, niacin, and vitamin C did not meet the Korean RDAs. Average bone mineral density in carpus was positively correlated to the body weight, the total body water, the lean body mass, and the obesity index, respectively(p<0.01, p<0.01, p<0.01 and p<0.01). The body weight, the total body water, and the lean body mass showed the significant negative correlations with the animal iron intake(p<0.05, p<0.01 and p<0.01). The bone mineral density in the distal carpus was negatively correlated to the animal protein intake and the animal iron intake(p<0.05 and p<0.05). And the bone mineral density in the ultradis carpus and the average bone mineral density in the carpus were positively correlated to the plant calcium intake(p<0.05 and p<0.05). Therefore, more systematic studies to investigate the roles of protein, iron, and calcium in growth development of preschool children were required.

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Comparison of Correlations of Saturated Vapor Density for Some Refrigerants (냉매의 포화증기밀도 상관식 비교)

  • Park, Kyoung-Kuhn;Kang, Byung-Ha;Jang, Si-Youl
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.6
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    • pp.457-463
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    • 2007
  • Various correlations of saturated vapor density in a truncated power series form are tested and compared in this study. Saturated vapor density correlation can be expressed relating logarithmic reduced density to the reduced temperature. Five types of correlation has been investigated using saturated vapor density data for 22 pure substance refrigerants from ASHRAE (American Society of Heating, Reftigerating and Air-Conditioning Engineers, Inc.) property tables and NIST (National Institute of Standards and Technology) Chemistry Webbook. Correlations are fitted to the data points by least squares method. Data points are equally weighted. The best type of correlation among the five types is suggested. The results obtained indicate that the best correlations with 3, 4, and 5 terms yield average AAD's (Average Absolute Deviation) of 0.27%, 0.04%, and 0.02%, respectively, while widely used conventional correlations with 3, 4, and 5 terms yield those of 1.19%, 0.61%, and 0.17%. The suggested type of correlation could reduce the number of terms while improving performance.

A Microscopic Analysis on the Fundamental Diagram and Driver Behavior (교통기본도와 운전자 행태에 대한 미시적 분석)

  • Kim, Taewan
    • International Journal of Highway Engineering
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    • v.14 no.6
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    • pp.183-190
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    • 2012
  • PURPOSES : The fundamental diagram provides basic information necessary in the analysis of traffic flow and highway operation. When traffic flow is congested, the density-flow points in the fundamental diagram are widely scattered and move in a stochastic manner. This paper investigates the pattern of density-flow point transitions and identifies car-following behaviors underlying the density-flow transitions. METHODS : From a microscopic analysis of 722 fundamental diagrams of NGSIM data, a total of 20 transition patterns of fundamental diagrams are identified. Prominent features of the transition patterns are explained by the behavior of the leader and follower. RESULTS : It is found out that the average speed and the speed difference between the leader and the follower critically determine the density-flow transition pattern. The density-flow path is very sensitive to the values of vehicle speed and spacing especially at low speed and high density such that most fluctuations in the fundamental diagram in the congested regime is due to the noise of speed and spacing variations. CONCLUSIONS : The result of this study suggests that the average speed, the speed difference between the leader and the follower, and the random variations of speed and spacing are dominant factors that explain the transition patterns of a fundamental diagram.

Pore Characteristics of Porous Alumina Ceramics Fabricated from Boehmite Hydrosol and Alumina Particles (Boehmite 수화졸의 알루미나로 제조한 다공성 알루미나 세라믹스의 기공특성)

  • 오경영
    • Journal of the Korean Ceramic Society
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    • v.33 no.5
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    • pp.547-555
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    • 1996
  • Porous alumina ceramics were fabricated by pseudo-boehmite phydosol-gel process within/without commercial $\alpha$-alumina particles average 1 and 40 micron respectively. The pore characteristics of fired specimens were studied by the measurement of bulk density total porosity thyermal analysis pore volume pore distribution BET area XRD and SEM. with increasing of firing temperature pore volume and BET surface area were decreased and the average pore size was increased to approximately 146$\AA$ upto 80$0^{\circ}C$ by de-watering of [OH] and formation of $\alpha$-alumina. The fired relative density of the alumina-dispersed specimen with average 1 micron particle was increased with the amounts of dispersed particle by bimodal packing theory which is compared to the ones of specimen including of average 40 micron particle. It was confirmed that the percola-tion threshold in porous ceramics with coarser particle (40 micron) has formed between the transformed-alumina from hydrogel and dispersed-alumina of above 50 vol% particle and the total porosity was increased at the threshold point above.

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Asymptotics of the Variance Ratio Test for MA Unit Root Processes

  • Lee, Jin
    • Communications for Statistical Applications and Methods
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    • v.17 no.2
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    • pp.223-229
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    • 2010
  • We consider the asymptotic results of the variance ratio statistic when the underlying processes have moving average(MA) unit roots. This degenerate situation of zero spectral density near the origin cause the limit of the variance ratio to become zero. Its asymptotic behaviors are different from non-degenerating case, where the convergence rate of the variance ratio statistic is formally derived.