• Title/Summary/Keyword: Mass loss rates

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Effects of Muscle Mass and Fiber Number of Longissimus dorsi Muscle on Post-mortem Metabolic Rate and Pork Quality

  • Ryu, Youn-Chul;Choi, Young-Min;Kim, Byoung-Chul
    • Food Science and Biotechnology
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    • v.14 no.5
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    • pp.667-671
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    • 2005
  • The aim of this study is to investigate the effects of the muscle mass and fiber number on post-mortem metabolic rates and pork quality. Carcass traits, muscle fiber characteristics, and type of fiber composition were evaluated using a sample of 200 cross-bred pigs. The muscle mass was divided into two groups according to carcass weight and loin-eye area measurements (heavy or light). In addition, the muscle histological characteristics were divided into two groups according to the muscle fiber density and total number of muscle fibers (high or low). All the carcass traits were significantly different in the muscle mass groups. Increasing weight significantly affected the cross-sectional area (CSA) of all fibers. The low group, which had a low muscle fiber number indicating a larger CSA of fibers, and especially the heavy-low group had the highest CSA levels of fibers. The fiber number percentage and the area percentage were significantly different in the groups categorized by fiber number. The heavy-high group indicated a normal rate of pH decline and the R-value. In addition, pigs with a heavy muscle mass and high muscle fiber number indicated normal drip loss, lightness, and protein denaturation. The present results suggest that increasing the total muscle fiber number has a beneficial effect on increasing the muscle mass without deteriorating the meat quality.

The Effect of Sleep Loss on Energy and Metabolism (호르몬수면상실이 에너지와 대사에 미치는 영향)

  • Kang, Seung-Gul
    • Sleep Medicine and Psychophysiology
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    • v.19 no.1
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    • pp.5-10
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    • 2012
  • The release of hormones and the metabolism of human body are controlled by the circadian rhythm related to sleep-wake cycle. Growth hormone, prolactin, thyroid stimulating hormone, cortisol, glucose, and insulin-secretion rates fluctuate according to the sleep-wake cycle. In addition, sleep is related to the appetite regulation and carbohydrate and other energy metabolism. Hypocretin (orexin), an excitatory neuropeptide, regulates waking and diet intake, and the poor sleep increases diet intake. The short sleep duration increases one's body mass index and impairs the function of the endocrine and metabolism, causing increases in the risk of glucose intolerance and diabetes. The poor sleep quality and sleep disorders have similar impact on the metabolic function. In short, the sleep loss and the poor quality of sleep have a detrimental effect on the endocrine and energy metabolism. The improvement of sleep quality by the future research and appropriate clinical treatment would contribute to the decrease of the metabolic diseases such as diabetes.

Design and Performance Analysis of Conical Solar Concentrator

  • Na, Mun Soo;Hwang, Joon Yeal;Hwang, Seong Geun;Lee, Joo Hee;Lee, Gwi Hyun
    • Journal of Biosystems Engineering
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    • v.43 no.1
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    • pp.21-29
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    • 2018
  • Purpose: The objective of this study is to evaluate the performance of the conical solar concentrator (CSC) system, whose design is focused on increasing its collecting efficiency by determining the optimal conical angle through a theoretical study. Methods: The design and thermal performance analysis of a solar concentrator system based on a $45^{\circ}$ conical concentrator were conducted utilizing different mass flow rates. For an accurate comparison of these flow rates, three equivalent systems were tested under the same operating conditions, such as the incident direct solar radiation, and ambient and inlet temperatures. In order to minimize heat loss, the optimal double tube absorber length was selected by considering the law of reflection. A series of experiments utilizing water as operating fluid and two-axis solar tracking systems were performed under a clear or cloudless sky. Results: The analysis results of the CSC system according to varying mass flow rates showed that the collecting efficiency tended to increase as the flow rate increased. However, the collecting efficiency decreased as the flow rate increased beyond the optimal value. In order to optimize the collecting efficiency, the conical angle, which is a design factor of CSC, was selected to be $45^{\circ}$ because its use theoretically yielded a low heat loss. The collecting efficiency was observed to be lowest at 0.03 kg/s and highest at 0.06 kg/s. All efficiencies were reduced over time because of variations in ambient and inlet temperatures throughout the day. The maximum efficiency calculated at an optimum flow rate of 0.06 kg/s was 85%, which is higher than those of the other flow rates. Conclusions: It was reasonable to set the conical angle and mass flow rate to achieve the maximum CSC system efficiency in this study at $45^{\circ}$ and 0.06 kg/s, respectively.

Performance Analysis of Three-Dimensional Transonic Centrifugal Compressor Diffuser (3차원 천음속 원심압축기 디퓨져 성능연구)

  • Kim, Sang Dug;Song, Dong Joo
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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    • pp.217-222
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    • 1998
  • CSCM upwind flux difference splitting compressible Navier-Stokes method has been used to predict the transonic flows in centrifugal compressor diffuser. The modified cyclic TDMA and the mass flux boundary conditions were used as boundary conditions of the diffuser analysis. With the mass flux boundary condition and the $130{\times}80{\times}40$ grid, the compressible upwind Navier-Stokes method predicted the transonic diffuser flowfield successfully. Plow changes in the impeller exit region due to the strong interaction between impeller exit and vaned diffuser, broad flow separation on the suction surface near hub and shroud was observed from the results of the mass flow rates 6.0 and 6.2kg/s at 27000 rpm. The static pressure increased and the total pressure decreased through the flow passage of the channel diffuser, which were predicted better from the three-dimensional analysis than from the two-dimensional analysis due to the strong effect of the three-dimensional flow. The mass averaged loss coefficients and pressure coefficients were also studied.

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Atmospheric Corrosion of Hot Dip Zinc Coated Steel in Coastal and Rural Areas of Vietnam

  • Tru, Nguyen Nhi;Duyen, Le Khac;Han, Tran Mai
    • Corrosion Science and Technology
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    • v.16 no.5
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    • pp.241-246
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    • 2017
  • The comparative results of corrosion testing in humid tropical atmosphere in rural and coastal areas for hot dipped zinc coatings are presented below. The test was conducted in outdoor conditions over a period of five years. The mass loss and other performance characteristics of two types of zinc coatings were evaluated, analysed and discussed in relation to the climatic and environmental parameters. The corrosion rates of the coatings exposed to coastal conditions were about three times higher than the corrosion rates appreciated in rural conditions. The data demonstrates that the corrosion process obeys an equation of the form $M=At^n$, where M is the loss of metal and t is the time of exposure. A and n are constants which values depend on the environmental characteristics and the physicochemical behavior of the corrosion products respectively. Corrosion is strongly influenced by atmospheric time of wetness (TOW) and airborne salinity. The nature and composition of corrosion products are also considered. Simonkolleite, a major crystalline phase, was found in the zinc corrosion products exposed to coastal conditions, while zinc hydroxide and zinc hydrosulfate are easily found in rural settings.

Study on Engineering Barrier Role in Nuclear Waste Disposal

  • Hua, Zhang;Jianwen, Yang;Baojun, Li;Shanggeng, Luo
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.02a
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    • pp.73-82
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    • 2004
  • This paper studies the leaching behaviors of pyrochlore-rich synroc incorporated 46.8wt% simulated actinides waste under the five simulated geological disposal media, which included the bentonite, granite, granite + ferroferric oxide, granite + cement, bentonite + ferroferric oxide, respectively. The mass loss rates reached to equilibrium after 182 day and was 10-7 g/$\textrm{mm}^2{\cdot}d$. That suggests the mass loss rate of pyrochlore-rich synroc, loaded 46.8wt% actinides waste, was very low. The surfaces of the leached specimens were analyzed by XRD, SEM/EDS. The experimental results show that the pyrochlore-rich synroc samples in the systems, which contained bentonite and cement, have two new phases formed on the leached specimens surface at $90^{\circ}C$ for 728d; The bentonite and cement can retard the elements leaching; $Fe_3O_4$ can speed the elements leaching; Expect for Ti ion depleted on the sample surface, other ion, such as U, Zr, AI, Ca, were in equable states and Ba ion was enriched during test time, which indicated the simulated disposal media have good ability to retard the leaching behavior of the pyrochlore-rich synroc.

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Luminosities and Rates of Mass Loss of Some Galactic Wolf-Rayet Stars (은하 볼프-레이에 별의 광도와 질량손실률)

  • Woo, Jong-Ok
    • Publications of The Korean Astronomical Society
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    • v.4 no.1
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    • pp.16-30
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    • 1989
  • We present recent data of absolute measurements of flux emmitted in the visible continua of some galactic Wolf-Rayet stars, carried out by means of a two-channel scanner built up cooperatively by the Observatoire de Lyon and the Laboratoire d'Astronomie Spatiale. Our measurements lead to the determination of stellar angular diameters which enable us to compute log $L_*/L_{\odot}$ and to locate the WR stars in the HR diagram: The WR stars are cooler than the zero age main sequence (ZAMS) and the WN7, WN8 types appear more luminous than other subclasses. The stellar wind terminal velocities, $V_{\infty}$, deduced from the empirical relation of the effective temperatures by Underhil1(1983) and $V_{\infty}$ adopted from the work of Willis(1982) show about 2,000km/s. We derived the rate of mass loss for the program stars from the formula, $\dot{M}={\varepsilon}(T_{eff})\;L/V_{\infty}{\cdot}c$ by using the obtained effective temperatures, luminosities and $V_{\infty}$ in this work. Their values range from $\dot{M}=1.4{\times}10^{-5}$ to $\dot{M}=5.8{\times}10^{-5}\;\dot{M}_{\odot}/yr$.

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Nutritional Management in Patients with Chronic Obstructive Pulmonary Disease (만성폐쇄성폐질환 환자의 영양관리)

  • Lee, Kwan-Ho
    • Journal of Yeungnam Medical Science
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    • v.21 no.2
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    • pp.133-142
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    • 2004
  • Chronic obstructive pulmonary disease(COPD) is characterized by a not entirely reversible limitation in the airflow. An airflow limitation is progressive and associated with an abnormal inflammatory response of the lung to gases and harmful particles. In COPD, the weight loss is commonly observed and there is a negative impact on the respiratory as well as skeletal muscle function. The pathophysiological mechanisms that result in weight loss in COPD are not fully understood. However, the mechanisms of weight loss in COPD may be the result of an increased energy expenditure unbalanced by an adequate dietary intake. The commonly occurring weight loss and muscle wasting in COPD patients adversely affect the respiratory and peripheral muscle function, the exercise capacity, the health status, and even the survival rates. Therefore, it is very valuable to include management strategies that the increase energy balance in order to increase the weight and fat free mass. A Better understanding of the molecular and cellular pathological mechanisms of COPD can improve the many new directions for both the basic and clinical investigations. The Nutritional supply is an important components of a multidisciplinary pulmonary rehabilitation program. Future studies combining an exercise program, the role of anabolic steroids, nutritional individualization, a more targeted nutritional therapy, and the development of new drugs including anti-cytokines is needed for the effective management of COPD.

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The Change of Biomechanical Milieu after Removal of mstnnnentation in lrunbar Arthrodesis Stiffness of fusion Mass: Finite Element Analysis (척추 유합술 후, 인접 분절의 스트레스에 대한 척추경 나사못에 대한 영향)

  • Kang, Kyoung-Tak;Chun, Heoung-Jae;Son, Ju-Hyun;Kim, Ho-Joong
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.664-667
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    • 2008
  • Since the advent of pedicle screw fixation system, posterior spinal fusion has markedly increased This intemal fixation system has been reported to enhance the fusion rates, thereby becoming very popular procedure in posterior spinal arthrodesis. Although some previous studies have shown the complications of spinal instruments removal, i.e. loss of correction and spinal collapse in scoliosis or long spine fusion patients, there has been no study describing the benefit or complications in lumbar spinal fusion surgery of one or two level. In order to clarify the effect of removal of instruments on mechanical motion profile, we simulated a finite element model of instrumented posterolateral fused lumbar spine model, and investigated the change of mechanical motion profiles after the removal of instrumentation.

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A Sensitivity Analysis of Centrifugal Compressors Empirical Models

  • Baek, Je-Hyun;Sungho Yoon
    • Journal of Mechanical Science and Technology
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    • v.15 no.9
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    • pp.1292-1301
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    • 2001
  • The mean-line method using empirical models is the most practical method of predicting off-design performance. To gain insight into the empirical models, the influence of empirical models on the performance prediction results is investigated. We found that, in the two-zone model, the secondary flow mass fraction has a considerable effect at high mass flow-rates on the performance prediction curves. In the TEIS model, the first element changes the slope of the performance curves as well as the stable operating range. The second element makes the performance curves move up and down as it increases or decreases. It is also discovered that the slip factor affects pressure ratio, but it has little effect on efficiency. Finally, this study reveals that the skin friction coefficient has significant effect on both the pressure ratio curve and the efficiency curve. These results show the limitations of the present empirical models, and more resonable empirical models are reeded.

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