• Title/Summary/Keyword: efficiency of scale

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Particle relaxation method for structural parameters identification based on Monte Carlo Filter

  • Sato, Tadanobu;Tanaka, Youhei
    • Smart Structures and Systems
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    • v.11 no.1
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    • pp.53-67
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    • 2013
  • In this paper we apply Monte Carlo Filter to identifying dynamic parameters of structural systems and improve the efficiency of this algorithm. The algorithms using Monte Carlo Filter so far has not been practical to apply to structural identification for large scale structural systems because computation time increases exponentially as the degrees of freedom of the system increase. To overcome this problem, we developed a method being able to reduce number of particles which express possible structural response state vector. In MCF there are two steps which are the prediction and filtering processes. The idea is very simple. The prediction process remains intact but the filtering process is conducted at each node of structural system in the proposed method. We named this algorithm as relaxation Monte Carlo Filter (RMCF) and demonstrate its efficiency to identify large degree of freedom systems. Moreover to increase searching field and speed up convergence time of structural parameters we proposed an algorithm combining the Genetic Algorithm with RMCF and named GARMCF. Using shaking table test data of a model structure we also demonstrate the efficiency of proposed algorithm.

Effect of high-energy neutron source on predicting the proton beam current in the ADS design

  • Zheng, Youqi;Li, Xunzhao;Wu, Hongchun
    • Nuclear Engineering and Technology
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    • v.49 no.8
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    • pp.1600-1609
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    • 2017
  • The accelerator-driven subcritical system (ADS) is driven by a neutron source from spallation reactions introduced by the injected proton beam. Part of the neutron source has energy as high as a few hundred MeV to a few GeV. The effects of high-energy source neutrons ($E_n$ > 20 MeV) are usually approximated by energy cut-off treatment in practical core calculations, which can overestimate the predicted proton beam current in the ADS design. This article intends to quantize this effect and propose a way to solve this problem. To evaluate the effects of high-energy neutrons in the subcritical core, two models are established aiming to cover the features of current experimental facilities and industrial-scale ADS in the future. The results show that high-energy neutrons with $E_n$ > 20 MeV are of small fraction (2.6%) in the neutron source, but their contribution to the source efficiency is about 23% for the large scale ADS. Based on this, a neutron source efficiency correction factor is proposed. Tests show that the new correction method works well in the ADS calculation. This method can effectively improve the accuracy of the prediction of the proton beam current.

Control of Turbid Water Transport with Filamentous Mat (섬모상 매트에 의한 탁수이동차단에 관한 실험적 연구)

  • Yu, Jianghua;Yi, Qitao;Kim, Youngchul
    • Journal of Korean Society on Water Environment
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    • v.26 no.1
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    • pp.44-51
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    • 2010
  • A lab-scale apparatus for turbid water transport control was tested and examined. The channel had a dimension of $100cm{\times}30cm{\times}15cm$ (length${\times}$hight${\times}$width). And the turbidity water was prepared using two types of particles, bentonite and loess. The channel equipped with filamentous mat was operated under various shock load conditions. In the control channel, instantly, turbid water mixed with the clean water inside the channel and turbidity prevails the entire channel. While in the mat-equipped channel, it increases only at the bottom. Overall, the filamentous mat gave capture efficiency of 70~90% compared with the control group. The capture efficiency of turbid particles decreased with increased input turbidity flux. The result of experimental run on how turbid particles are separated in the mat channel shows that settling, filtration and attachment are the main processes. Meanwhile, turbidity was diffused from the channel bottom due to turbidity gradient before and after mat zone. The particle size before mat zone was lightly coarser than that after mat zone.

Efficiency Increase and Input Power Decrease of Converted Prototype Pump Performance

  • Oshima, Masao
    • International Journal of Fluid Machinery and Systems
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    • v.9 no.3
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    • pp.205-212
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    • 2016
  • The performance of a prototype pump converted from that of its model pump shows an increase in efficiency brought about by a decrease in friction loss. As the friction force working on impeller blades causes partial peripheral motion on the outlet flow from the impeller, the increase in the prototype's efficiency causes also a decrease in its input power. This paper discusses results of analyses on the behavior of the theoretical head or input power of a prototype pump. The equation of friction-drag coefficient for a flat plate was applied for the analysis of hydraulic loss in impeller blade passages. It was revealed that the friction-drag of a flat plate could be, to a certain degree, substituted for the friction drag of impeller blades, i.e. as a means for analyzing the relationship between a prototype pump's efficiency increase and input power decrease.

A Note on the Efficiency Based Reliability Measures for Heterogeneous Populations

  • Cha, Ji-Hwan
    • Communications for Statistical Applications and Methods
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    • v.18 no.2
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    • pp.201-211
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    • 2011
  • In many cases, populations in the real world are composed of different subpopulations. Furthermore, in addition to the heterogeneity in the lifetimes of items, there also could be the heterogeneity in the efficiency or performance of items. In this case, the reliability measures should be defined in a different way. In this article, we consider the mixture of stochastically ordered subpopulations. Efficiency based reliability measures are defined when the performance of items in the subpopulations has different levels. Discrete and continuous mixing models are studied. The concept of the association between the lifetime and the performance of items in subpopulations is defined. It is shown that the consideration of efficiency can change the shape of the mixture failure rate dramatically especially when the lifetime and the performance of items in subpopulations are negatively associated. Furthermore, the modelling method proposed in this paper is applied to the case when the stress levels of the operating environment of items are different.

Performance of a Pilot-scale Rice Husk Incinerator

  • Park, Seung J.;Kim, Myoung H.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1996.06c
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    • pp.906-917
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    • 1996
  • This study was conducted to find possible application areas of the by-products generated from the incineration of rice husk. To this end, a pilot-scale rice husk incinerator system was constructed and its performed test was carried. Major findings are summarized as follows. 1. The rice husk incinerator system developed in this study performed satisfactory in terms of thermal efficiencies. At the optimum operating conditions, thermal conversion efficiency and heat exchanger efficiency was 97% ad 60%, respectively, while overall thermal efficiency of the system was 58%. Under all conditions tested, temperatures in the combustion chamber were quite uniform and crystallization of SiO$_2$ in the ash was negligible. 2. NOx and SOx content in the flue gas was well below the legal limit but the CO concentration was around the legal limit. 3. Thermal energy from combustion was successfully recovered by a heat exchanger to provide hot water, ash was found a good supplementary cementing m terial, and the flue gas also was an acceptable $CO_2$ supplier to greenhouses.

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Pilot Scale Test of Non-woven Fabric Filter Separation Activated Sludge Process for Practical Application on Domestic Wastewater Reclamation (파일럿 규모의 침지식 부직포 여재 활성슬러지 공정의 시스템 처리 특성에 관한 연구)

  • Lee, Sang-Woo;Choi, Chul-hoi;Park, Young-mi;Seo, Gyu-Tae
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.2
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    • pp.289-294
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    • 2006
  • A pilot scale non-woven fabric filter separation activated sludge system was investigated for practical application on domestic wastewater reclamation and reuse. The system was operated in A/O (Anaerobic/Oxic) process with submerged filter module in the aerobic compartment. In the test of two types of filter materials ($70g/m^2$ and $35g/m^2$), the initial flux (0.42m/d) could be maintained for about three months by regular air backwashing of $70g/m^2$ filter at 0.3m water head. The removal efficiency of organic matter by the system was BOD 93.3%, CODcr 96.3%, SS 96.7%. The effluent quality was 7.8mg/L, 12mg/L and 5mg/L for BOD, CODcr and SS, respectively. The water quality was enough to meet a standard for domestic reuse without human contact. T-N removal efficiency was 49.9% at internal recycle rate 2Q and C/N ratio 3.3. The removal efficiency of T-P was 50% with average effluent concentration, 2.6mg/L.

Evaluation on the Efficiency of Cored Wire Feeding in Addition of Alloying Elements into Cu Melt (코어드 와이어 피딩에 의한 Cu 용탕에의 합금 첨가 시 효율 평가)

  • Kang, Bok-Hyun;Kim, Ki-Young
    • Journal of Korea Foundry Society
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    • v.33 no.6
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    • pp.248-253
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    • 2013
  • To add alloying elements into a pure copper melt, the wire-feeding efficiency of cored (alloy containing) wire was evaluated using a commercial, computational fluid-dynamics program. The model design was based on an industrial-scale production line. The variables calculated included wire feed rate, melt temperature, wire diameter, melt flow rate and wire temperature. Efficiency was evaluated after a series of calculations based on the penetration depth of the alloy-wire into the molten copper bath. Of the five variables investigated, the wire feed rate and wire diameter were the most influential factors affecting the feeding efficiency of the cored-wire.

A Study on Load Transfer Efficiency of Skewed Transverse Joint of Concrete Pavement by the Fatigue Test (피로실험에 의한 콘크리트 포장체 경사가로줄눈부의 하중전달율에 관한 연구)

  • Hwang, Seung-Eui;Bae, Ju-Seong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.203-211
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    • 2001
  • This paper presents load transfer efficiency of skewed transverse joint of jointed concrete pavement with the fatigue model test. A 1/12 scale model was used to satisfy the geometry, loading, material similitude, which are variables to the skew angel of transverse joint. As the test results by fatigue load 700kgf applied, the deflection and stress of transverse joint were decreased as to increasing of skew angle of transverse joint. In addition, load transfer efficiency of transverse joint with skew angle is better than the load transfer efficiency of transverse joint without skew angle.

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Treatment Efficiency and Organic Matter Characterization of Wastewater through Activated Sludge Process and Advanced Wastewater Treatment Process (활성슬러지공정과 고도처리공정에 따른 하수처리수의 처리효율과 유기물 특성)

  • Hong, JiHea;Sohn, Jinsik
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.6
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    • pp.807-813
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    • 2004
  • Wastewater was treated by two different treatment processes; activated sludge process and advanced wastewater treatment process (KNR process) using lab-scale experiment. Two treated wastewater showed good treatment efficiency of organic matter removal, up to 90% removal. Nitrogen and phosphorus were not effectively removed though activated sludge process, while KNR process showed good removal efficiency of nitrogen and phosphorus; 56% nitrogen removal and 95% phosphorus removal. KNR process showed better removal efficiency of organic matter, nitrogen, and phosphorus compared to activated sludge process. Organic matter characterization was tracked though measurement of UV scan, SUVA, and XAD fractionation. Treated wastewater showed higher SUVA value than wastewater influent, indicting less aromatic characteristic of organic matter. XAD fractionation showed hydrophilic fraction decreased though wastewater treatment, suggesting microbes preferentially digest hydrophilic and aliphatic molecules rather than hydrophobic and aromatic molecules of organic matter.