• 제목/요약/키워드: shear effect

검색결과 4,334건 처리시간 0.036초

Effect of Sodium Bicarbonate Injection in Pre-rigor Porcine M. Longissimus lumborum on Pork Quality

  • Yang, H.S.;Moon, S.S.;Jeong, J.Y.;Choi, S.G.;Joo, S.T.;Park, G.B.
    • Asian-Australasian Journal of Animal Sciences
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    • 제19권6호
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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.

괭생이모자반(Sargassum horneri)으로부터 추출한 다당의 이화학적 특성 (Isolation and Characterization of Polysaccharides Purified from Brown Alga Sargassum horneri)

  • 구재근;정성우
    • 한국수산과학회지
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    • 제53권5호
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    • pp.681-687
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    • 2020
  • Physicochemical properties of fucoidan and alginate extracted from Sargassium horneri were investigated. The alginates were extracted and purified via three different routes (CaCl2, HCl and ethanol routes), and their rheological properties at various concentrations and temperatures were determined. The yield of fucoidan was 3.08%, and it was mainly composed of fucose and galactose. Fourier-transform infrared spectrum of fucoidan showed strong absorption band at 1,254 and 827 cm-1 corresponding to the sulfate group. Flow behavior of the alginate solution was characterized using the power-law model. The consistency index increased with increasing concentrations. The sodium alginate solution (1.5%) exhibited Newtonian behavior when extracted via the CaCl2 and HCl routes, while it exhibited pseudoplastic behavior when extracted via the ethanol route. The effect of temperature on the flow behavior was investigated in terms of the activation energy (Ea), which was obtained using the Arrhenius equation. The Ea value corresponding to the alginate solution decreased with increasing shear rates. The Ea values corresponding to the alginate solutions purified via the CaCl2, HCl, and ethanol routes were 13.54-18.64 kJ/mol, 13.42-19.21 kJ/mol, and 9.51-10.67 kJ/mol, respectively. The low Ea values corresponding to the solutions extracted via the ethanol route suggest that the flow behavior does not depend significantly on temperature.

CFD Study on the Influence of Atmospheric Stability on Near-field Pollutant Dispersion from Rooftop Emissions

  • Jeong, Sang Jin;Kim, A Ra
    • Asian Journal of Atmospheric Environment
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    • 제12권1호
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    • pp.47-58
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    • 2018
  • The aim of this work is to investigate the effect of atmospheric stability on near-field pollutant dispersion from rooftop emissions of a single cubic building using computational fluid dynamics (CFD). This paper used the shear stress transport (here after SST) k-${\omega}$ model for predicting the flow and pollutant dispersion around an isolated cubic building. CFD simulations were performed with two emission rates and six atmospheric stability conditions. The results of the simulations were compared with the data from wind tunnel experiments and the result of simulations obtained by previous studies in neutral atmospheric condition. The results indicate that the reattachment length on the roof ($X_R$) obtained by computations show good agreement with the experimental results. However, the reattachment length of the rooftop of the building ($X_F$) is greatly overestimated compared to the findings of wind tunnel test. The result also shows that the general distribution of dimensionless concentration given by SST k-${\omega}$ at the side and leeward wall surfaces is similar to that of the experiment. In unstable conditions, the length of the rooftop cavity was decreased. In stable conditions, the horizontal velocity in the lower part around the building was increased and the vertical velocity around the building was decreased. Stratification increased the horizontal cavity length and width near surface and unstable stratification decreased the horizontal cavity length and width near surface. Maintained stability increases the lateral spread of the plume on the leeward surface. The concentration levels close to the ground's surface under stable conditions were higher than under unstable and neutral conditions.

Supplementary effects of higher levels of various disaccharides on processing yield, quality properties and sensory attributes of Chinese - style pork jerky

  • Chen, Chih-Ming;Lin, Hsien-Tang
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권12호
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    • pp.1773-1783
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    • 2017
  • Objective: This study evaluated the supplementary effect of higher concentrations of various disaccharides on processing yield, major physicochemical properties, and sensory attributes of Chinese-style pork jerky (CSPJ). Methods: CSPJ samples were prepared by marinating sliced ham (4 mm) with three dissaccharides, including sucrose, lactose, and maltose, at 0%, 15%, 18%, 21%, and 24%. Subsequently, the CSPJ samples were dried and roasted. The moisture content, water activity, crude protein, moisture-to-protein ratio, pH, processing yield, shear force, color, and sensory attributes of the CSPJ samples were evaluated. Results: The quality characteristics of CSPJ samples prepared with sucrose were more acceptable. By contrast, CSPJ samples prepared with lactose showed the lowest scores. However, the processing yield and moisture content were the highest for CSPJ samples prepared with lactose, which may be associated with improved benefits for cost reduction. Furthermore, sucrose and lactose supplementation resulted in contrasting quality characteristics; for example, CSPJ samples with sucrose and maltose supplementation had higher sensory scores for color than samples with lactose supplementation. Additionally, most quality characteristics of CSPJ samples with sucrose supplementation contrasted with those of the samples with lactose supplementation; for example, the samples with sucrose supplementation had higher scores for sensory attributes than those with lactose supplementation. Conclusion: Sucrose supplementation up to 21% to 24% was associated with the highest overall acceptability scores (5.19 to 5.80), enhanced quality characteristics, increased processing yield, and reduced production cost.

Effects of red glasswort as sodium chloride substitute on the physicochemical properties of pork loin ham

  • Jeong, Tae-Jun;Kim, Tae-Kyung;Kim, Hyun-Wook;Choi, Yun-Sang
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권4호
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    • pp.662-669
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    • 2020
  • Objective: This study was conducted to evaluate the effect of red glasswort (RG) (Salicornia herbacea L.) curing on the physicochemical, textural and sensory properties of cooked pork loin ham (M. longissimus thoracis et lumborum). Methods: All treatments were cured with different salt and RG powder levels. RG0 treatment was prepared with only 4% NaCl (w/w) as a control, and RG25, 3% NaCl:1% RG (w/w); RG50, 2% NaCl:2% RG (w/w); RG75, 1% NaCl:3% RG (w/w); RG100, 0% NaCl:4% RG (w/w) treatments were prepared sequentially. All samples were individually vacuum packaged in polyethylene bags and stored for 7 d at 3℃±1℃. Results: The results showed that as the rate of RG substitution increased, pH value, redness, myofibrillar protein solubility, and myofibrillar fragmentation index increased (p<0.05), but salt concentration and shear force decreased (p<0.05). However, there were no significant differences in cooking loss and moisture content. In terms of sensory evaluation, RG100 exhibited higher scores in tenderness and juiciness than RG0 (p<0.05). Conclusion: The partial substitution of NaCl by RG could improve the physicochemical properties, textural and sensory characteristics of cooked pork loin. Therefore, it is suggested that RG as a natural salt replacer could be an effective ingredient for developing low-sodium cured hams.

수치모형에 의한 연안해역 해수운동의 분석 (Analysis of the Hydraulic Behaviour in the Nearshore Zone by a Numerical Model)

  • 이희영;정선길
    • 물과 미래
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    • 제27권2호
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    • pp.73-83
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    • 1994
  • 확산현상, 표사유동 및 인간의 여러 활동이 실제 연안해역에서 일어나므로 연안해역 해수운동의 물리적 특성을 파악하고 해석하는 것은 중요한 의미를 지닌다. 본 연구에서는 연안해역에서의 파랑변형과 평균해수위 변동 그리고 연안유속 분포양상에 대해 여러 인자들이 미치는 영향을 2차원 유한차분 모형(ADI, Up-wind)을 이용하여 분석하였다. 계산결과로는 수치모형을 해저경사가 일정한 2차원 지형에 적용하여 해저경사, 입사파고, 파향각, 파주기, 마찰계수 및 수평확산계수가 연안해역 특히 쇄파대내에서 파랑변형, 평균해수위 변동 및 연안유속 분포에 미치는 영향을 분석하였다.

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굴곡 융착면을 이용한 고밀도폴리에틸렌 관의 버트 융착 공정에서의 열유체 거동 수치모사 (Numerical Simulation of Heat and Flow Behaviors in Butt-fusion Welding Process of HDPE Pipes with Curved Fusion Surface)

  • 유재현;최선웅;안경현;오주석
    • Korean Chemical Engineering Research
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    • 제55권4호
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    • pp.561-566
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    • 2017
  • 폴리머 재질의 관을 융착 시키기 위해서는 버트 융착 공정을 거치는데, 최근 융착면에 굴곡을 주어 융착 강도를 높이고자 하는 시도가 있었다. 본 연구에서는 융착면의 굴곡이 폴리머의 열유체 거동 및 융착 강도에 어떠한 영향을 미칠 것인지 2차원 축대칭 평면에서 유한요소법을 사용하여 살펴보았으며, 고밀도폴리에틸렌 관을 대상으로 하였다. 열유화 단계에서 융착면의 형상을 따라 굴곡진 상경계면이 나타남을 확인할 수 있었다. 접합 단계에서는 굴곡진 상경계면과 융착면 사이에서의 멜트의 압착 흐름이 나타남을 확인할 수 있었으며, 굴곡융착부의 낮은 전단율은 관의 축과 수직 방향 배향을 완화시켜 융착부 강도 향상에 도움을 줄 수 있을 것으로 예상된다.

Effect of hydrofluoric acid-based etchant at an elevated temperature on the bond strength and surface topography of Y-TZP ceramics

  • Yu, Mi-Kyung;Lim, Myung-Jin;Na, Noo-Ri;Lee, Kwang-Won
    • Restorative Dentistry and Endodontics
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    • 제45권1호
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    • pp.6.1-6.8
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    • 2020
  • Objectives: This study investigated the effects of a hydrofluoric acid (HA; solution of hydrogen fluoride [HF] in water)-based smart etching (SE) solution at an elevated temperature on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics in terms of bond strength and morphological changes. Materials and Methods: Eighty sintered Y-TZP specimens were prepared for shear bond strength (SBS) testing. The bonding surface of the Y-TZP specimens was treated with 37% phosphoric acid etching at 20℃-25℃, 4% HA etching at 20℃-25℃, or HA-based SE at 70℃-80℃. In all groups, zirconia primers were applied to the bonding surface of Y-TZP. For each group, 2 types of resin cement (with or without methacryloyloxydecyl dihydrogen phosphate [MDP]) were used. SBS testing was performed. Topographic changes of the etched Y-TZP surface were analyzed using scanning electron microscopy and atomic force microscopy. The results were analyzed and compared using 2-way analysis of variance. Results: Regardless of the type of resin cement, the highest bond strength was measured in the SE group, with significant differences compared to the other groups (p < 0.05). In all groups, MDP-containing resin cement yielded significantly higher bond strength values than MDP-free resin cement (p < 0.05). It was also shown that the Y-TZP surface was etched by the SE solution, causing a large change in the surface topography. Conclusions: Bond strength significantly improved when a heated HA-based SE solution was applied to the Y-TZP surface, and the etched Y-TZP surface was more irregular and had higher surface roughness.

등대구조물의 면진시스템 적용방안 연구 (Application of Isolation System to the Lighthouse Structure)

  • 허무원;천영수;김동영
    • 한국구조물진단유지관리공학회 논문집
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    • 제17권1호
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    • pp.27-36
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    • 2013
  • 본 연구에서는 등대 구조물을 대상으로 한 면진기술 적용방안을 제시함으로써 지진에 대해 무방비상태에 놓여 있는 등대구조물의 지진안전도 확보방안을 제시하였다. 또한, 제안된 면진기술 적용방안을 활용하여 내진설계 이전에 지어진 등대를 대상으로 등대전체를 면진하였을 경우와 등대 렌즈만을 면진하였을 경우에 대하여 면진효과를 분석해 보았다. 해석결과, 등대 전체를 면진화하였을 경우 최대응답가속도와 층전단력 측면에서 충분한 면진효과를 얻은 반면, 등대 렌즈만을 면진화한 경우에는 렌즈부의 면진효과는 유효한 것으로 나타났으나 등대 자체의 안전이 확보되지 못한 상황에서는 등대의 파괴가 선행될 가능성이 있음에 주의할 필요가 있는 것으로 나타났다. 또한 등대전체와 렌즈를 동시에 면진화한 경우 비 면진구조 대비 유효한 면진효과는 나타내었지만, 최대응답가속도가 등대전체를 면진화한 경우보다 증가하는 경향을 나타내었으며, 렌즈의 면진화로 인한 층전단력의 감소가 미소함으로 이중면진의 적용으로 인한 실효성은 그 효과가 크지 않은 것으로 나타났다.

능이버섯 첨가가 우육의 물리화학적 및 관능적 특성에 미치는 영향 (Effects of the Sarcodon aspratus on the Physicochemical and Sensory Properties of Cooked Beef)

  • 송영선;이승아;조정원;이종호;조재선
    • 한국식품영양과학회지
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    • 제30권2호
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    • pp.266-272
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    • 2001
  • An instrumental analysis of cooked beef was carried out along with sensory evaluation to find out the effect of Sarcodon aspratus on the physicochemical and sensory characteristics in comparision with kiwi fruit and pear. Transmission electron microscopy showed the muscle fiber started to be degraded when treated with Sarcodon aspratus(1,000unit) for 10 min at $25^{\circ}C$. No distinct sarcomere, A-band, and Z-line was observed when treated with Sarcodon aspratus for 60 min at same condition. The moisture content of cooked beef was increased in proportion to the increment of Sarcodon aspratus, kiwi fruit and pear. In the texture, shear force of cooked beef was decreased with the increment of Sarcodon aspratus, kiwi fruit and pear. In terms of color, L-value was decreased by addition of Sarcodon aspratus, whereas L-value was increased by addition of kiwi fruit and pear in dose-dependent manners. a-value and b-value was decreased with the increment of Sarcodon aspratus, kiwi fruit and pear. There were significant differences (p<0.05) in the sensory characteristics of the samples in which control was most preferred in taste and flavor. As the content of Sarcodon aspratus, kiwi fruit and pear was increased, the score of juiciness and tenderness was increased. In the overall acceptance, score of 0.05~0.1% Sarcodon aspratus and 10% pear was not different from that of control. Therefore, it can be concluded that 0.05~0.1% addition of Sarcodon aspratus might be desirable for the improvement of texture and juiciness of cooked beef.

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