• Title/Summary/Keyword: Loss Correlations

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Quantum Coherent Dissociation in a Hybrid Atom-light System with Photon Loss

  • Xiaoyang Yuan;Jialu Yin;Jiahao Xu;Yixiao Huang;Zhengda Hu
    • Current Optics and Photonics
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    • v.8 no.1
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    • pp.105-111
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    • 2024
  • We investigate the effect of photon loss on pair production in a hybrid atom-light system. The loss of light field not only affects the generation of photons, but also prevents the generation of atomic collective excitation, although the atoms are not influenced directly. We propose an unbalanced homodyne detection of the number of atomic collective excitation that overcomes the challenge caused by counting uncertainty in practical measurement. In discussion, we show that the intermode correlations and the number correlation is closely related to the initial input state, while the quadrature correlations are independent of the initial state and always exhibit opposite intermode correlations even in the presence of loss.

A Canonical Correlation Analysis of the Relationship between Menu Management Variables and Performance in Contract-Foodservice Operations (위탁 급식 점포의 메뉴 운영 요인과 성과의 연관성에 관한 연구)

  • Park, Ju-Yeon;Kim, Tae-Hee
    • Journal of the East Asian Society of Dietary Life
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    • v.18 no.6
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    • pp.1089-1098
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    • 2008
  • The principal objective of this study was to reveal the relationship between the menu management indicators and menu performance indicators in contract-foodservice operations. Menu indicators differed according to the type of business, type of contract, type of serving, and number of service lines. In accordance with the results of our correlation analysis, we noted significant correlations between menu performance indicators and menu management indicators. The first of these was the correlation between the food cost ration and meal counts, food loss, and the use of prepared vegetables. The second of these was the correlation between food cost per meal and forecasting error, food loss, and inventory turnover. The last of these correlations was the negative correlation between menu CSI(customer satisfaction index) and the use of prepared vegetables. According to the results of our canonical correlation analysis, 2 significant functions were identified. In the first function, we noted significant correlations between meal counts, use of prepared vegetables, food loss, and food cost ratio. Additionally, we noted significant correlations between forecasting error, inventory turnover, food loss, and food cost per meal in the second function. Menu management indicators had no influence on customer satisfaction.

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Performance analysis of mixed-flow fans considering the low flow characteristics (저유량 특성을 고려한 사류 송풍기의 성능 해석)

  • Oh, Hyoung Woo;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.110-115
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    • 2000
  • The mean streamline analysis using the empirical loss correlations has been developed for performance prediction of industrial mixed-flow fan impellers in the present study. New simple, but effective, models for the additional Euler input work characteristic and an internal recirculation loss due to internal flow reversal under the low flowrate conditions are proposed in this paper. Comparison of overall performance predictions with six sets of test data of mixed-flow fans is accomplished to demonstrate the accuracy of the proposed models. Predicted performance curves by the present set of loss models agree fairly well with experimental data for a variety of mixed-flow fan impellers over the entire operating conditions. The prediction method presented herein can be used efficiently in the conceptual design phase of mixed-flow fan impellers.

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The Influence of the Grief of loss on the Subjective well-being in the Elderly (고령자의 상실감이 주관적 안녕감에 미치는 영향)

  • Hun Yoon ;Soon Chul Lee ;Ju Seok Oh
    • Korean Journal of Culture and Social Issue
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    • v.13 no.2
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    • pp.1-15
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    • 2007
  • The purpose of this study is to find how the factors of "Grief of loss" affect on the subjective well-being of elderly('the satisfaction with life', 'the positive affect', 'the negative affect). One hundred of subjects, over age 65, participated in the survey and we could find that the "Grief of loss" was composed of four sub-factors('economical loss', 'loss from being parted by death', 'loss of physical functions', 'loss of relations'). These four sub-factors of "Grief of loss" showed negative correlations with the scores of the satisfaction with life. However, three other sub-factors except 'loss from being parted by death' showed negative correlations with the scores of 'the positive affect'. On the other hand, other three sub-factors except 'economical loss' showed positive correlations with the scores of 'the negative affect'. Especially, the 'economical loss' was affecting on 'the negative affect' and 'the positive affect' significantly. Also, 'loss of relations' was affecting on both 'the negative affect' and 'the satisfaction with life''. Two out of the four sub-factors, 'economical loss' and 'loss from being parted by death', showed no significant effects on the subjective well-being. This results insists us that the emotional supports, especially from their offspring, are truly important for elderly to overcome their Grief of loss('loss of physical functions', 'loss of relations')

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Windmilling Characteristics of Centrifugal-Flow Turbojets

  • Yoo, Il-Su;Song, Seung Jin;Lim, Jin Shik
    • Journal of Mechanical Science and Technology
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    • v.18 no.11
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    • pp.2021-2031
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    • 2004
  • A new nondimensional method for predicting the windmilling performance of centrifugal -flow turbojet engines in flight has been developed. The method incorporates loss correlations to estimate the performance of major engine components. Given basic engine geometry, flight Mach number, and ambient conditions, this method predicts transient and steady-state windmilling performance. Thus, this method can be used during the preliminary design stage when detailed hardware geometry and component performance data are not yet available. A nondimensional time parameter is newly defined, and using this parameter, the transient performance of different types of turbojets (e.g. centrifugal vs. axial) is compared. In addition, the predictions' sensitivity to loss correlations, slip factors, and inlet ambient temperatures are analyzed.

The Influence of Physical Resource Loss and Gain on Well-Being of People in Low-Income and the Mediating Role of Economic Stability (저소득층의 물리적 자원의 상실 및 획득이 안녕감에 미치는 영향과 경제적 안정의 매개 역할)

  • Park, Sunyoung
    • Korean Journal of Social Welfare
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    • v.65 no.2
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    • pp.335-356
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    • 2013
  • Physical resources are central to coping with economic hardships for people in low-income, yet life experiences such as resource loss and gain and their relationships with a sense of well-being received scarce attention. Thus this study investigated levels of loss and gain of physical resources, economic stability and well-being of 254 adults who participated in welfare-to-work programs; correlations and paths among these variables; and direct and indirect effects of economic stability by structural equation modeling. Major results were: first, the levels of resource loss and gain were below a moderate level and the level of gain was significantly higher than the loss level. Second, in the relationships with both economic stability and well-being, resource loss showed negative correlations, while resource gain showed significantly positive correlations. Third, the negative direct effect of resource loss either on the economic stability or on the well-being respectively was significant and the indirect effect on well-being through economic stability was also significant. Finally, the direct effect of resource gain on either economic stability or well-being was significant; and the indirect effect of resource gain on well-being was also significant. Thus in both models for resource loss and gain, the indirect effect of economic stability was significant, which supports partial mediation model. Based on these results, implications for social work practice and research were examined, particularly for enabling social work practice to utilize information regarding resource loss and gain, economic stability, and a sense of well-being that were embedded in the community life of people in low-income.

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Off-Design Performance Prediction of an Axial Flow Compressor Stage Using Simple Loss Correlations (간단한 손실모델을 이용한 단단축류압축기 탈설계점 성능예측)

  • 김병남;정명균
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.12
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    • pp.3357-3368
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    • 1994
  • Total pressure losses required to calculate the total-to-total efficiency are estimated by integrating empirical loss coefficients of four loss mechanisms along the mean-line of blades as follows; blade profile loss, secondary flow loss, end wall loss and tip clearance loss. The off-design points are obtained on the basis of Howell's off-design performance of a compressor cascade. Also, inlet-outlet air angles and camber angle are obtained from semi-empirical relations of transonic airfoils' minimum loss incidence and deviation angles. And nominal point is replaced by the design point. It is concluded that relatively simple loss models and Howell's off-design data permit us to calculate the off-design performance with satisfactory accuracy. And this method can be easily extended for off-design performance prediction of multi-stage compressors.

CFD ANALYSIS OF HEAVY LIQUID METAL FLOW IN THE CORE OF THE HELIOS LOOP

  • Batta, A.;Cho, Jae-Hyun;Class, A.G.;Hwang, Il-Soon
    • Nuclear Engineering and Technology
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    • v.42 no.6
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    • pp.656-661
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    • 2010
  • Lead-alloys are very attractive nuclear coolants due to their thermo-hydraulic, chemical, and neutronic properties. By utilizing the HELIOS (Heavy Eutectic liquid metal Loop for Integral test of Operability and Safety of PEACER$^2$) facility, a thermal hydraulic benchmarking study has been conducted for the prediction of pressure loss in lead-alloy cooled advanced nuclear energy systems (LACANES). The loop has several complex components that cannot be readily characterized with available pressure loss correlations. Among these components is the core, composed of a vessel, a barrel, heaters separated by complex spacers, and the plenum. Due to the complex shape of the core, its pressure loss is comparable to that of the rest of the loop. Detailed CFD simulations employing different CFD codes are used to determine the pressure loss, and it is found that the spacers contribute to nearly 90 percent of the total pressure loss. In the system codes, spacers are usually accounted for; however, due to the lack of correlations for the exact spacer geometry, the accuracy of models relies strongly on assumptions used for modeling spacers. CFD can be used to determine an appropriate correlation. However, application of CFD also requires careful choice of turbulence models and numerical meshes, which are selected based on extensive experience with liquid metal flow simulations for the KALLA lab. In this paper consistent results of CFX and Star-CD are obtained and compared to measured data. Measured data of the pressure loss of the core are obtained with a differential pressure transducer located between the core inlet and outlet at a flow rate of 13.57kg/s.

Mechanisms, Experimental Results, Empirical Correlations and Analytic Models of Beat Transfer in Containment Building Following a LOCA (냉각재 상실 사고시 격납 용기내에 있어서의 열전달에 관한 기구, 실험결과, 선험 관계식 및 해석적 모형들에 관한 고찰)

  • Jong Ho Choi;Soon Heung Chang
    • Nuclear Engineering and Technology
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    • v.15 no.2
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    • pp.123-134
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    • 1983
  • Estimates of the rate of heat removal from the containment atmosphere following a loss of colant accident (LOCA) are important to the prediction of containment peak pressure and temperature which are essential parameters in designing the containment building. An overall survey and discussion of mechanisms, experimental results, empirical correlations and analytical models that are relevant to the heat transfer inside the containment have been made. As a result of this review, the current state of the knowledge about tile containment heat transfer can be understood and it is known that more investigations are needed to avoid the misuse of various correlations.

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Off-design Performance Prediction of Centrifugal Pumps by Using TEIS model and Two-zone model (TEIS 모델과 두 영역 모델을 이용한 원심 펌프의 탈 설계 성능 예측)

  • Yoon, In-Ho;Baek, Je-Hyun
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.574-579
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    • 2000
  • In this study. an off-design performance prediction program for centrifugal pumps is developed. To estimate the losses in an impeller flow passage, two-zone model and two-element in series(TEIS) model are used. At impeller exit. the mixing process occurs with an increase in entropy. In two-zone model. there are both primary zone and secondary zone for an isentropic core flow and an average of all non-isentropic streamtubes respectively. The level of the core flow diffusion in an impeller was calculated by using TEIS model. While internal losses in an impeller an automatically estimated by using the above models, some empirical correlations far estimating external losses. far example, disk friction loss, recirculation loss and leakage loss are used. In order to analyze the vaneless diffuser flow. the momentum equations for the radial and tangential directions are used and solved together with continuity and energy equations.

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