• Title/Summary/Keyword: normal mixtures

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Compressive, shear and torsional strength of beams made of self-compacting concrete

  • Mazloom, Moosa;Saffari, Amirali;Mehrvand, Morteza
    • Computers and Concrete
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    • v.15 no.6
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    • pp.935-950
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    • 2015
  • The aim of this study is to provide experimental data regarding the compressive, shear and torsional strength of self-compacting concrete (SCC) used in rectangular beams, and then comparing the results with the equations presented by the CSA A23.3-04 and ACI 318-11. In fact, the gathered information in this field is quite useful for calibrating the computer models of other researchers. The other goal of this study was to investigate the effects of silica fume and superplasticizer dosages on the mechanical properties of SCC. In this research, SCC is made based on 16 different type mixing layout. Also two normal concrete (NC) or vibrating concrete are constructed to compare the results of SCC and NC. This work concentrated on concrete mixes having water/binder ratios of 0.45 and 0.35, which contained constant total binder contents of $400kg/m^3$ and $500kg/m^3$, respectively. The percentages of silica fume that replaced cement were 0% and 10%. The superplasticizer dosages utilized in the mixtures were 0.4%, 0.8%, 1.2% and 1.6% of the weight of cement. Beam dimensions used in this test were $30{\times}30{\times}120cm^3$. The results of this research indicated that shear and torsional strength of SCC beams to be used in computer models can be calculated utilizing the equations presented in CSA A23.3-04 and ACI 318-11.

Targeted chiral lipidomics analysis of bioactive eicosanoid lipids in cellular systems

  • Lee, Seon-Hwa;Blair, Ian A.
    • BMB Reports
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    • v.42 no.7
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    • pp.401-410
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    • 2009
  • We have developed a targeted lipidomics approach that makes it possible to directly analyze chiral eicosanoid lipids generated in cellular systems. The eicosanoids, including prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs) and alcohols (HETEs), have been implicated as potent lipid mediators of various biological processes. Enzymatic formations of eicosanoids are regioselective and enantioselective, whereas reactive oxygen species (ROS)-mediated formation proceeds with no stereo-selectivity. To distinguish between enzymatic and non-enzymatic pathways of eicosanoid formation, it is necessary to resolve enantiomeric forms as well as regioisomers. High sensitivity is also required to analyze the eicosanoid lipids that are usually present as trace amounts (pM level) in biological fluids. A discovery of liquid chromatography-electron capture atmospheric pressure chemical ionization/mass spectrometry (LC-ECAPCI/MS) allows us to couple normal phase chiral chromatography without loss of sensitivity. Analytical specificity was obtained by the use of collision-induced dissociation (CID) and tandem MS (MS/MS). With combination of stable isotope dilution methodology, complex mixtures of regioisomeric and enantiomeric eicosanoids have been resolved and quantified in biological samples with high sensitivity and specificity. Targeted chiral lipidomics profiles of bioactive eicosanoid lipids obtained from various cell systems and their biological implications have been discussed.

Quality Poultry Meat Production (양질의 닭고기 생산 방안)

  • 남기홍
    • Korean Journal of Poultry Science
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    • v.26 no.1
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    • pp.1-25
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    • 1999
  • Concerns about meat quality, including chicken meat, for the human diet has led to many attempts to manipulate the carcass fat and increase the eating quality. For actual eating quality, the birds must be grown and finished in a manner that results in meat that are tender, succulent and of good flavor, as well as being free from any foreign taint, flavor or safety hazard. Tenderization treatment with high voltage(820V) electrical stimulation and prechill muscle tensioning would improve the tenderness of chicken meat. Proper programs for the withdrawal of feed and water require a team approach for maximizing yield of meat and minimizing carcass contamination. Also effding of supplemental levels of-tocopherol to poultry with vegetable or fish oils increases of desirable polyunsaturated fatty acid(PUFA) content and stablizes the meat against rancidity and fish off-flavors. The nutritional effects of varying dietary ingredients on broiler carcass fat content are also important. Increasing the levels of energy in the ration increases the carcass fat content, while increasing the proteing levels decreases carcass fat content. Supplement-tation of poultry diets with amino acids such as methionine, lysine, glycine and tryptophan as well as amino acid such as well as amino acid mixtures can reduce body fat deposition. Normal stress leads to chicken muscular damage resulting in reduced meat quality, but this can be controlled by preslaughter management practices. Feed manufactures can utilize ntilize nutrient modulation to control pale soft exudative(PSE)syndrome. Finally, the success in poultry meat production depends on the consistent achievement of carefully selected levels of quality. Quality assurance should be the wider function of incorporating quality into the production system and the combination of motivating quality into actions and operations.

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Septo-optic dysplasia plus diagnosed in a middle-aged woman

  • Oh, Seung Tae;Kang, Mi-Ri;Oh, Seong-il;Kim, Eung Gyu;Kim, Sang Jin;Seo, Jung Hwa;Chung, Eun Joo;Ji, Ki-Hwan
    • Annals of Clinical Neurophysiology
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    • v.20 no.2
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    • pp.85-88
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    • 2018
  • Septo-optic dysplasia is a congenital anomaly with diverse phenotypes from normal to mixtures of visual abnormality, endocrine dysfunction, psychomotor retardations and epileptic seizures. It is characterized by optic atrophy, pituitary dysfunction and midline structure abnormalities in corpus callosum or septum pellucidum. Diagnosis of septo-optic dysplasia plus is made when cortical malformations accompanied. Here we report a middle-aged woman with septo-optic dysplasia plus having unilateral optic atrophy, agenesis of septum pellucidum and cortical malformations.

Prediction of elastic modulus of steel-fiber reinforced concrete (SFRC) using fuzzy logic

  • Gencoglu, Mustafa;Uygunoglu, Tayfun;Demir, Fuat;Guler, Kadir
    • Computers and Concrete
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    • v.9 no.5
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    • pp.389-402
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    • 2012
  • In this study, the modulus of elasticity of low, normal and high strength steel fiber reinforced concrete has been predicted by developing a fuzzy logic model. The fuzzy models were formed as simple rules using only linguistic variables. A fuzzy logic algorithm was devised for estimating the elastic modulus of SFRC from compressive strength. Fibers used in all of the mixes were made of steel, and they were in different volume fractions and aspect ratios. Fiber volume fractions of the concrete mixtures have changed between 0.25%-6%. The results of the proposed approach in this study were compared with the results of equations in standards and codes for elastic modulus of SFRC. Error estimation was also carried out for each approach. In the study, the lowest error deviation was obtained in proposed fuzzy logic approach. The fuzzy logic approach was rather useful to quickly and easily predict the elastic modulus of SFRC.

Properties of recycled green building materials applied in lightweight aggregate concrete

  • Wang, Her-Yung;Hsiao, Darn-Horng;Wang, Shi-Yang
    • Computers and Concrete
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    • v.10 no.2
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    • pp.95-104
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    • 2012
  • This study uses recycled green building materials based on a Taiwan-made recycled mineral admixture (including fly ash, slag, glass sand and rubber powder) as replacements for fine aggregates in concrete and tests the properties of the resulting mixtures. Fine aggregate contents of 5% and 10% were replaced by waste LCD glass sand and waste tire rubber powder, respectively. According to ACI concrete-mixture design, the above materials were mixed into lightweight aggregate concrete at a constant water-to-binder ratio (W/B = 0.4). Hardening (mechanical), non-destructive and durability tests were then performed at curing ages of 7, 28, 56 and 91 days and the engineering properties were studied. The results of these experiments showed that, although they vary with the type of recycling green building material added, the slumps of these admixtures meet design requirements. Lightweight aggregate yields better hardened properties than normal-weight concrete, indicating that green building materials can be successfully applied in lightweight aggregate concrete, enabling an increase in the use of green building materials, the improved utilization of waste resources, and environmental protection. In addition to representing an important part of a "sustainable cycle of development", green building materials represent a beneficial reutilization of waste resources.

A Study on Performance Characteristics of Propane/Isobutane Refrigerant Mixtures in a Domestic Small Multi-Refrigeration System (프로판/이소부탄(R-290/R-600a) 혼합 냉매를 적용한 가정용 소형 멀티 냉동시스템의 성능특성에 관한 연구)

  • Kim Sanguk;Lee MooYeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.2 s.233
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    • pp.271-278
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    • 2005
  • In this paper, the performance of Kim-chi refrigerator with three evaporator and one compressor was investigated in employing $55\%$ propane and $45\%$ isobutane (R290/R600a) refrigerant mixture as an alternative refrigerant of R134a. The drop-in test was performed by varying both refrigerant charge and capillary tube length in order to find both the performance and reliability of a small multi-refrigeration system. Results show that the power consumption is decreased by about $15\%$ and COP is increased by about $10\%$, respectively as compared to the baseline system using R-134a. In addition, the propane/isobutane refrigerant mixture system took advantage of the minimization of modification and redesigning of system components because thermodynamic properties such as saturation pressure, temperature, normal boiling point(NBP) characteristics are similar to those of R134a. The reduction of sales cost is caused by the decrease of refrigerant cost per unit mass and refrigerant charge amount necessary for the refrigeration system.

Mineral Status of Soils and Forages in Southwestern Punjab-Pakistan: Micro-minerals

  • Khan, Zafar Iqbal;Hussain, A.;Ashraf, M.;McDowell, L.R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.8
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    • pp.1139-1147
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    • 2006
  • This study was conducted to evaluate the trace elemental nutritive values of soil and forages collected from southwestern part of the province of Punjab, Pakistan. Soil and forage samples were collected fortnightly for two seasons. The concentrations of some trace minerals varied greatly among seasons and sampling periods. Seasonal effects were found in all soil micro-minerals except zinc, while forage iron, zinc, and selenium were affected by seasonal changes. Sampling periods effects were observed in all soil minerals and in forage copper, iron, zinc, and manganese only. All soil mineral levels except cobalt and selenium were sufficiently high to meet the requirements of plants for normal growth during both seasons. In contrast, soil Co and Se levels were severely deficient during both seasons and considered inadequate for plant growth. Soil Fe, Zn, Co, and Se levels were higher, and Cu and Mn lower during winter than those during summer. Forage Zn levels during summer were at marginal deficient levels, and in contrast, all other forage micro-minerals were within the required range for ruminants during both seasons. Although forage mico-minerals were within the range required by the ruminants, they were not sufficiently high to prevent the predisposition to various diseases caused by nutrient deficiency. Consequently, grazing animals at this location need continued mineral supplementation of these elements with a mixtures of high bio-availability rather than of high micro-mineral contents to support optimum ruminant productivity.

Evaluation of Characteristic Improvement of Waste-Polyethylene Asphalt Concrete (폐폴리에틸렌 필름 재활용 아스팔트 콘크리트의 특성 분석)

  • Kim, Kwang-Woo;Li, Xing-Fan;Jeong, Seung-Ho;Lee, Soon-Jae;Lee, Gi-Ho
    • International Journal of Highway Engineering
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    • v.4 no.1 s.11
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    • pp.161-170
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    • 2002
  • This study is a fundamental research for recycling waste polyethylene film(WPF) in asphalt concrete for roadway pavement. The objective of this study is to develop technology of making waste polyethylene asphalt mixture and evaluate properties of the asphalt concrete containing WPF. Asphalt concrete for surface course of pavement was produced through an appropriate mix-design using dense-graded and gap-graded aggregates. Marshall mix design, indirect tensile strength test, wheel tracking test and tensile fatigue test were performed. Test result showed that some WPF asphalt mixtures had a high tensile property and good resistances against rutting and fatigue cracking, compared with normal asphalt mixture.

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Friction and Wear of Nitrogen Incorporated Diamond-like Carbon Films Under a Vacuum

  • Yoon, Eui-Sung;Kong, Hosung;Lee, Kwang-Ryeol;Oh, Jae-Eung
    • Tribology and Lubricants
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    • v.11 no.5
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    • pp.59-65
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    • 1995
  • Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum ($3 \times 10^{-5}$ Torr) using a ball (AISI 52100 steel)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor deposition method. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than that of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films were explained with the changes in chemical structures of the films. Result also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanisms and roles of the polymer-like wear debris were presented and discussed.