• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.256-259
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• 2008

Ejector system is a device to transport a low-pressure secondary flow by using a high-pressure primary flow. Ejector system is, in general, composed of a primary nozzle, a mixing section, a casing part for suction of secondary flow and a diffuser. It can induce the secondary flow or affect the secondary chamber pressure by both shear stress and pressure drop which are generated in the primary jet boundary. Ejector system is simple in construction and has no moving parts, so it can not only compress and transport a massive capacity of fluid without trouble, but also has little need for maintenance. Ejectors are widely used in a range of applications such as a turbine-based combined-cycle propulsion system and a high altitude test facility for rocket engine, pressure recovery system, desalination plant and ejector ramjet etc. The primary interest of this study is to set up an applicable model and operating conditions for an ejector in the condition of sonic and subsonic, which can be extended to the hydrogen fuel cell vehicle. Experimental and theoretical investigation on the sonic and subsonic ejectors with a converging-diverging diffuser was carried out. Optimization technique and numerical simulation was adopted for an optimal geometry design and satisfying the required performance at design point of ejector for hydrogen recirculation. Also, some ejectors with a various of nozzle throat and mixing chamber diameter were manufactured precisely and tested for the comparison with the calculation results.

• Steel and Composite Structures
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• v.26 no.6
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• pp.719-731
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• 2018

Concrete filled steel tubular (CFST) laced columns have been widely used in high rise buildings in China. Compared to solid-web columns, this type of columns has a larger cross-section with less weight. In this paper, four concrete filled steel tubular laced columns consisting of 4 main steel-concrete tubes were tested under cyclic loading. Hysteresis and failure mechanisms were studied based on the results from the lateral cyclic loading tests. The influence of each design parameter on restoring forces was investigated, including axial compression ratio, slenderness ratio, and the size of lacing tubes. The test results show that all specimens fail in compression-bending-shear and/or compression-bending mode. Overall, the hysteresis curves appear in a full bow shape, indicating that the laced columns have a good seismic performance. The bearing capacity of the columns decreases with the increasing slenderness ratio, while increases with an increasing axial compression ratio. For the columns with a smaller axial compression ratio (< 0.3), their ductility is increased. Furthermore, with the increasing slenderness ratio, the yield displacement increases, the bending failure characteristic is more obvious, and the hysteretic loops become stouter. The results obtained from the numerical analyses were compared with the experimental results. It was found that the numerical analysis results agree well with the experimental results.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.898-904
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• 2006

Effects of sodium bicarbonate (SBC) injection on meat quality and functionality of porcine M. longissimus lumborum were investigated. Fifteen pigs ($100{\pm}5kg$) were randomly selected at a commercial slaughter plant. After slaughtering the loins were dissected from the carcass before chilling at approximately 30 minutes post mortem. The loins were divided into four cuts for sample treatment, and SBC of 0.25 M, 0.40 M and 0.75 M was injected (2% w/w) using a syringe. As SBC injection level was increased, muscle pH increased significantly (p<0.05). SBC injection decreased lightness ($L^*$) values on the surface of muscle. Moreover, with injection of SBC, drip loss %, cooking loss % and shear force were significantly (p<0.05) decreased, whereas WHC and $Na^+$ content were significantly (p<0.05) increased. From panel testing of uncooked pork loin, no significant differences (p>0.05) were found in aroma, off-flavor and drip between injection of SBC at different levels and the control, although color and acceptability were significantly lower (p<0.05) in control pork loin compare with injection of SBC at 0.75 M. In cooked pork loin from the panel test, aroma, flavour, off-flavour and juiciness were found to be similar (p>0.05) on all treatments, but tenderness and acceptability were significantly higher (p<0.05) with injection of SBC at 0.75 M than for control loin. Myofibrillar protein solubility of muscles treated with SBC was significantly (p<0.05) higher than that of the control, although no significant differences (p>0.05) were found in sarcoplasmic protein solubility between the treatments. These results indicated that SBC injection into pre-rigor porcine M. longissimus lumborum could improve ultimate pork quality characteristics such as meat color, water-holding capacity, and could inhibit muscle protein denaturation due to an increase in muscle pH.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.1
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• pp.89-99
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• 2016

The effects of retail cut type on chemical, quality and nutritional characteristics of horse meat were studied. Jeju female breed horses (n = 9) at 32-mo-old were slaughtered and the carcasses at 24 h post-mortem were fabricated into 10 retail cuts including: tender-loin, loin, strip-loin, shoulder-chuck-roll, shoulder-clod, top-round, outside-round, brisket, short-plate-brisket, and shank. The results revealed that all of parameters (chemical, meat quality and nutritional composition) examined significantly (p<0.05) differed between the cuts. The chemical composition range (minimum to maximum) of cuts was found as such: moisture 65.06% to 71.69%; protein 19.07% to 21.28%; collagen 1.40% to 2.45%; fat 2.56% to 12.14% and cholesterol 55.76 to 79.50 mg/100 g. Shoulder-chuck-roll had the highest pH and water-holding capacity, while top-round had the highest cooking loss. Shear force ranged between the cuts from $2.80kg/cm^2$ to $4.98kg/cm^2$. The Cu, Fe, and Zn contents ranged between the cuts from 1.52 mg/kg to 2.75 mg/kg, 21.25 mg/kg to 30.85 mg/kg, and 16.51 mg/kg to 40.42 mg/kg, respectively. Additionally, most of the cuts studied showed favorable polyunsaturated fatty acid/saturated fatty acid, n-3/n-6 and essential amino acid/non-essential amino acid ratios.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.4
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• pp.522-528
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• 2018

Objective: This study evaluated inclusion of buckwheat silage to the diet of growing lambs in terms of meat quality as compared to maize silage. Methods: Buckwheat, rich in total phenols (TP, 33 g/kg dry matter [DM]), was harvested at the end of the milk stage and ensiled in 40 kg plastic bags after wilting (294 g/kg silage DM). A total of 18 growing lambs ($21.6{\pm}1.2$) were individually fed isonitrogenous and isoenergetic total mixed rations (TMR) for 75 d that either contained buckwheat or maize silage at DM proportions of 0.50. At the end of feeding trail all lambs were slaughtered to assess carcass characteristics and meat quality. Results: Buckwheat silage increased (p<0.01) the DM intake of lambs as compared to maize silage, but had no effects (p>0.05) on live weight gain and feed efficiency. Carcass weight, dressing percentage, meat pH, water holding capacity, cooking loss, shear force ($kg/cm^2$), and total viable bacteria count of meat did not differ (p>0.05) between the treatments. However, TP content of meat increased (p<0.001) by feeding buckwheat TMR. Feeding buckwheat TMR also decreased (p<0.05) the b* values of meat. Conclusion: The results provide that buckwheat silage is palatable and could successfully include TMR of growing lambs with no adverse effects on performance, carcass and meat quality. Additionally, feeding buckwheat silage to lambs offers increased TP in meat.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.18-25
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• 2012

This paper estimates the ductility of reinforced concrete columns according to configurations of transverse reinforcement. A total of 8 reinforced concrete columns were cast and tested in flexure. The test variables in this study were the configurations, yield strength, and amount of transverse reinforcement. The specimens had a cross-section of $250{\times}250mm$ and had a shear span-to-depth ratio of 4.1 to induce flexural failure. In the test, cyclic lateral load was applied to the specimens with a constant axial load. The experimental result indicated that the specimens with proposed configurations of transverse reinforcement showed higher ductility and energy dissipation capacity than the specimens with rectangular tie.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.25-32
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• 2016

The pile-cap connection part which transfers foundation loads through pile body is critical element regarding flexural and shear force because the change of area, stress, and stiffness occurs in the this region suddenly. The purpose of this study is to investigate the structural behavior of pile-cap connection dependent on fabrication methods using conventional PHC pile and composite PHC pile. A series of test under cyclic lateral load was performed and the connection behavior was discussed. From the test results, it was found that the initial rotational stiffness of pile-cap connection was affected by the length of pile-head inserted in footing and the location of longitudinal reinforcing bars. The types of pile and location of longitudinal reinforcing bars governed the behavior of pile-cap connection regarding load-carrying capacity, ductility, and energy dissipation.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.277-282
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• 2005

The current study was conducted to investigate the effect of organic selenium in mushroom cultured media (MCM) on beef quality. Each five of 20 Hanwoo steers(20 - 24 month, approximately 613 kg) were assigned to four levels of the selenium content(O.l, 0.3, 0.6, 0.9 dry matter based ppm), and the feeding treatments were enforced for 12 weeks. The results showed that m. longissimus from the 0.1 ppm feeding supplementation had greatly higher intramuscular fat content than other treatments(13.1 %). In meat color, the 0.1 ppm treatment showed the lowest lightness(CIE $L^*$)(P< 0.05) and had a tendency to have lower redness(CIE $a^*$). The treatment had no noticeable effect on moisture, protein, and ash content, cooking loss, water-holding capacity and purge loss. The 0.3 ppm treatment resulted in the toughest meat(assessed by WB-shear force) with 4.54 kg / inch', while other groups showed a similar toughness ranging from 3.3 to 3.7 kg/ inchl . Sensory characteristics in juiciness and flavor intensity had a tendency of increasing as organic selenium concentration increased, but tenderness was not influenced by the contents. The result indicated that the organic selenium feeding affects meat qualities to different extent, and further study is required to examine anti-oxidant effect of selenium in vivo.

• Korean Journal of Poultry Science
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• v.35 no.2
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• pp.191-196
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• 2008

This study was carried out to investigate the changes in carcass characteristics during slaughter process and to evaluate the physical properties of ostrich muscles. After blooding, pH of carcass was declined rapidly and showed 5.89 of final pH, whilst temperature was slightly decreased during slaughter process. Carcass of ostrich yielded 49.3%. For the comparison between muscles, m. gastrocneminus and m. iliofemoralis externus showed a significantly high pH (P<0.05). The muscle of which pH tended to be high in water holding capacity (WHC), however, m. gastrocneminus showed a significantly low WHC (P<0.05) due to low moisture content. M. obturatorius medialis showed the significantly lower shear force, whilst m. gastrocneminus was higher than other muscles (P<0.05). Therefore the results indicated that the production of high quality carcass was to reduce the time during slaughter process, and that high WHC and tenderness of ostrich meat had a potential application as a substitutional species to other animals.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.191-195
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• 2016

This study aimed to investigate the physicochemical properties of chicken breast ham manufactured with broiler (BR), spent broiler breeder hen (SBBH), and spent laying hen (SLH). The water holding capacity and final yield of chicken breast ham manufactured with SLH was significantly lower than chicken breast ham manufactured with BR and SBBH (P<0.05). The lightness and redness of chicken breast ham manufactured with SBBH were significantly higher than those of chicken breast ham manufactured with SLH (P<0.05). The yellowness of chicken breast ham manufactured with BR and SLH was significantly higher than that of chicken breast ham manufactured with SBBH (P<0.05). The shear force of chicken breast ham manufactured with SLH was the highest. The tenderness and overall acceptability of chicken breast ham manufactured with BR and SBBH were significantly higher than those of chicken breast ham manufactured with SLH. Therefore, SBBH and SLH can lead to various textures of chicken breast hams.