• Title/Summary/Keyword: replacement level

Search Result 807, Processing Time 0.031 seconds

The Effect of Replacement Level of Recycled Aggregate on the Properties of High-Performance Concrete (고성능 콘크리트의 특성에 미치는 재생골재 치환율의 영향)

  • Yang Keun-Hyeok;Kim Yong-Seok
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.11a
    • /
    • pp.181-184
    • /
    • 2004
  • The objective of this experimental study is to grasp the effect of replacement level of high-quality recycled aggregate on the properties of high-performance concrete. The mixing types were divided into two series based on containing $0\%\;and\;15\%$ fly-ash. Replacement level of recycled aggregate ranged from $0\%\;to\;100\%$. Test results showed that the initial slump and the fluid velocity were independent on the replacement level of recycled aggregate, and the loss of compressive strength was almost $20\%$ with the recycled aggregate only.

  • PDF

Preventive Replacement Model Based on Substitutive Characteristics : the case of periodic observation (대용특성을 이용한 예방정비모형 : 주기적으로 관측하는 경우)

  • Gu, Ja-Hang;Jang, Jung-Sun;Kim, Won-Jung
    • Journal of Korean Society for Quality Management
    • /
    • v.20 no.2
    • /
    • pp.33-43
    • /
    • 1992
  • Items are assumed to fail by degradation. An appropriate stochastic model of such item is a cumulative process in which an item can fail only when the total amount of wear exceeds a prespecified failure level. This paper presents replacement policy in which an item is replaced at a certain level of wear before failure or at failure, whichever occurs first. Yet, when measuring the item wear level is very expensive, destructive or time-consuming, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. The item's wear level could usually be estimated by monitoring such substitutive characteristics only except for a breakdown, which may be observed immediately at its occurrence. The purpose of this paper is to find an optimal periodic replacement policy based on such substitutive characteristics that balance the cost of replacement with the cost of failure and result in a minimum total long-run average cost per unit time. The optimal level of substitutive characteristics to replace the item is obtained. Numerical example illustrate how the model can be used to determine the optimal replacement policy.

  • PDF

Effect of Isolated Soy Protein on Sponge Cake Quality (분리대두단백이 스폰지 케일의 품질에 미치는 영향)

  • 이경애
    • Korean journal of food and cookery science
    • /
    • v.13 no.3
    • /
    • pp.299-303
    • /
    • 1997
  • The effects of partial replacement of flour with isolated soy protein (ISP) on sponge cake quality were investigated. The replacement did not cause any significant changes in physical characteristics of sponge cakes including specific gravity, specific volume and expansion ratio. As the level of ISP replacement increased, the sponge cakes were darker in color, harder, chewier and drier than control groups. The textural characteristics (hardness, cohesiveness, springiness, gumminess and chewiness) of the sponge cakes also increased as the level of flour replacement increased. Up to 15% of the flour could be replaced by ISP without diminishing the sponge cake quality.

  • PDF

The Effect of Recycled Coarse Aggregate Replacement Level on the Mechanical Properties of Concrete (순환굵은골재 치환율에 따른 콘크리트의 역학적 특성)

  • Jeon, Esther;Yun, Hyun-Do;You, Young-Chan;Lee, Sea-Hyun;Shim, Jong-Woo;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.505-508
    • /
    • 2006
  • This experimental study is to evaluate the effects of recycled coarse aggregate replacement level on the mechanical properties of concrete produced at Batcher plant. The main test parameter was replacement level of recycled coarse aggregate with the ratio of 0, 30, 60 and 100% to the natural coarse aggregate. From the test results, it was found that compressive strength, elastic modulus and splitting strength are decreased with the increased proportion of replacement level. Therefore, some design coefficients or recommendations for elastic modulus and splitting strength of concrete need to be reconsidered with minor reduction factor of '0.85'.

  • PDF

The Effect of Recycled Coarse Aggregates Replacement Level on Localized Fracture and Acoustic Emission of Concrete in Compression (순환굵은골재 치환율에 따른 콘크리트의 압축파괴 및 음향방출특성)

  • Kim, Yun-Su;Yun, Hyun-Do;You, Young-Chan
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.249-252
    • /
    • 2006
  • When concrete is subjected to uniaxial compression, the failure process is normally initialed from a localized zone. The localization of failure governs structural behaviors of concrete. In this paper, the compressive strength and failure behavior of recycled coarse aggregate concrete with different replacement level of recycled coarse aggregates are investigated using acoustic emission(AE). AE characteristics of concrete were investigated during the entire loading period. For these purpose, four recycled coarse aggregate replacement level (i.e 0%, 30%, 60% and 100%) were considered in this paper. Result from this study show AE signal, AE method can apply to investigate a compressive failure mode according to recycled coarse replacement level.

  • PDF

A Study on a Preventive Replacement Model by the Dynamic Programming Method (동적 계획법에 의한 예방교체모형에 관한 연구)

  • 조재립;황의철
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.10 no.16
    • /
    • pp.75-80
    • /
    • 1987
  • This paper is deals with the preventive replacement for the equipment which fails only when the total amount of damage reaches a prespecified failure level. Most of replacement model use time as their decision variable, but it is not appropriate for the cases in which failures dependent on their cumulative damage levels. In this paper, a new type preventive replacement model is introduced in which an equipment is replaced before failure when the cumulative damage reaches a certain level or replaced on failure, whichever occures first. The optimal replacement damage levels which minimize total expected cost are obtained by the Dynamic programming Method when the number of use of the equipment is finite. A numerical example is also presented. The optimal preventive replacement policy when the equipment will be used for a finite time span is also discussed.

  • PDF

Effect of Partial Replacement of Concentrates with Barhar (Artocarpus lakocha) Leaves on Growth Performance of Kids Fed a Mixed Jungle Grass-based Diet

  • Das, A.;De, D.;Katole, S.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.24 no.1
    • /
    • pp.45-55
    • /
    • 2011
  • A feeding trial was conducted to study the replacement value of concentrates with Barhar (Artocarpus lakocha) leaves on growth performance of kids fed a mixed jungle grass-based diet. Fifteen Sikkim local kids, about 4 months of age and body weight ranging from 5.8 to 9.2 kg, were randomly distributed into three groups of five. Kids were stall fed ad lib with mixed jungle grass collected from the nearby forest and native scrubland. The kids in group I received supplementary concentrate (Maize 35%, mustard cake 32%, rice bran 30%, mineral mixture 2% and common salt 1%) at approximately 2% of BW. For groups II and III, 25 and 50% of the concentrate was replaced with Barhar (Artocarpus lakocha) leaves, respectively. Total dry matter intake (DMI) was not significantly different among groups. Digestibility of CP decreased (p<0.05) and that of NDF increased (p<0.01) with increasing level of Barhar leaves in the diet. Digestibility of ADF (p<0.01), hemi cellulose (p<0.05) and cellulose (p<0.01) was higher in groups II and III than in group I. Ruminal pH and TVFA concentration were not significantly different among groups. Rumen ammonia-N concentration decreased (p<0.01) with increased level of Barhar leaves in the diet. Similarly, plasma urea nitrogen and blood glucose levels were reduced (p<0.05) with increasing level of Barhar leaves in the diet. Replacement of concentrate with Barhar resulted in reduced Hb and lower serum iron concentration. Levels of other serum metabolites including minerals were not altered by the replacement. Average daily gain (ADG) was 53.3, 54.4 and 41.8 g/d in groups I, II and III, respectively. ADG was not adversely affected when the level of replacement was restricted to 25%. However, at 50% of replacement ADG was significantly lower than the control (p<0.05). Thus, it was concluded that Barhar leaves might replace 25% of the supplemental concentrate for growing Sikkim local kids fed on a mixed jungle grass-based diet.

Intravascular Hemolysis after Prosthetic Valve Replacement (인공판막 치환수술후의 용혈)

  • Jang, Won-Chae;Lee, Gye-Yeong;Kim, Sang-Hyeong
    • Journal of Chest Surgery
    • /
    • v.25 no.12
    • /
    • pp.1556-1562
    • /
    • 1992
  • Forty two consecutive patients who had had valve replacement with St. Jude Medical prosthesis were studied on a view point of intravascular hemolysis. Patients were consisted of 14 mitral valve replacement, and 7 aortic valve replacement, and 21 double, mitral and aortic, valve replacement. Serum LDH, indirect bilirubin, GOT, hemoglobin levels and ret-iculocyte count were pursued in postopeative 1st day, 3rd day, 7th day, 14th day and 21th day. Postoperatively, all patients were not detected paravalvular leakage on the ech-ocardiographical study. The patients with double valve replacement revealed higher levels of LDH on postopeative 14th day[P<0 05] than those with single valve replacement. Among the patients with single valve replacement, the patients with aortic valve replacement revealed slightly higher levels of entire postopeative data, but considered insignificant. There was correlation between the severity of hemolysis and the size of replaced aortic valve. In the postoperative LDH levels, the patients with small sized-aortic valve[less than 21mm in diameter] replacement revealed higher levels of postoperative 3rd day, 7th day and 14th day than those with large size[more than 23mm in diameter]. The patients with high level LDH of greater than 800 WU /L on postoperative 7th day were 61.9%[26 of 42]. The high LDH frequency of DVR was 71.4%[15 of 21], MVR 50.0%[7 of 14] and AVR, 57.1%[4 of 7]. The level of LDH declined gradualiy thereafter through postoperative 3 weeks. In conclusion, intravascular hemolysis after prosthetic valve replacement was dependent on position of valve replacement and size of valve. And this study supports the conventional valve selection and usage in our hospital. The patients with subclinical hemolysis after valve replacement should be placed on a close observation.

  • PDF

An Experimental Study on the Fundamental Properties of Electric Pole Recycled Aggregate(EPRA) and Characteristics of High Strength Concrete by Replacement Ratios of EPRA (폐전주 재생골재의 기초물성 및 대체율에 따른 고강도영역 재생골재 콘크리트의 특성에 관한 실험적 연구)

  • 이강우;이종호;강석표;최세진;최희용;김무한
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2001.05a
    • /
    • pp.495-500
    • /
    • 2001
  • In this study, it was analized and examined fundamental properties of Electric Pole Recycled Aggregate(EPRA) and hardened properties & chemical resistance with H$_2$SO$_4$by replacement ratios of EPRA, and the results are as follows 1) In the case of electric pole recycled coarse aggregate, All fundamental properties are better than that of normal recycled aggregate and both water absorption and amount of crushed loss are with level of natural aggregate 2) As the replacement ratio of electric pole recycled fine aggregate is increased strength development is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate 3) As the replacement ratio of electric pole recycled fine aggregate is increased chemical resistance is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate

  • PDF

Remote Cache Replacement Policy using Processor Locality in Multi-Processor System (다중 프로세서 시스템에서 프로세서 지역성을 이용한 원격 캐쉬 교체 정책)

  • Han Sang Yoon;Kwak Jong Wook;Jhang Seong Tae;Jhon Chu Shik
    • Journal of KIISE:Computer Systems and Theory
    • /
    • v.32 no.11_12
    • /
    • pp.541-556
    • /
    • 2005
  • The memory access latency of the system has been a primary factor of performance degradation in single-processor system and multi-processor system. The remote memory access latency takes a lot of overhead over the local memory access latency especially in the distributed shared-memory system. To resolve this problem, the multi-level cache architecture that contains a remote cache in the multi-processor system has been proposed. In this paper, we propose a new cache replacement policy that improves the performance of the multi-processor system with the remote cache. If the multi-level cache keeps the multi-level inclusion(MLI) property and uses the LRU(Least Recently Used) cache replacement policy, the LRU information of the higher-level cache(a processor cache) would be different with that of the lower-level cache(a remote cache). In this situation, the replacement of a remote cache line can induce the exchange of a processor cache line that is used by the processor. It is a main factor of performance degradation in a whole system. To alleviate this disadvantage of the LRU replacement polity, the new policy analyses tht processor's remote memory access pattern of each node and uses this information to reduce the number of invalidations of the useful cache line in the higher-level cache. The new replacement policy of the remote cache can improve the performance by $3.5\%$ in maximum and $2.5\%$ in average on SPLASH-2 benchmarks, compared to the general LRU cache replacement policy.