• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.4
• /
• pp.534-540
• /
• 2003

This study was conducted to investigate the effect of supplementation of galacto-oligosaccharides (GOS) on methane emission, nutrient digestibility, energy utilization and blood metabolites by Holstein cows fed silages. In two sequential digestion and respiratory trials, two non-lactating Holstein cows were arranged to a balanced incomplete block design. Experimental diets consisted of two silage types; orchardgrass (Dactylis glomerata L.) based silage (OS), mixed silage (orchardgrass based silage and alfalfa (Medicago sativa L.) silage) (MS), while two GOS levels were without supplementation (0) and 2% of dry matter intake supplementation (2). Four combination diets were OS-0, OS-2, MS-0 and MS-2. Significant effects of silage types and GOS supplementation levels were not observed for DM and OM intake. Whereas the digestibility of OM, NDF and ADF was significantly (p<0.05) higher in cows fed OS with and without GOS compared cows fed MS diets. As percentage of GE intake, fecal energy loss for OS diets was significantly (p<0.05) declined than for MS diets. In contrast, cows fed MS diets had lower (p<0.05) urine energy loss as a proportion of GE intake compared to OS diets. Energy loss as CH4 and heat production was numerically increased when cows fed both OS and MS with GOS supplementation. Compared to OS, CH4 emission in cows fed MS was numerically decreased by 10.8 %. Methane conversion ratio (energy loss as CH4 per unit of GE intake) for OS-0, OS-2, MS-0 and MS-2 were 7.1, 7.2, 6.8 and 7.0, respectively. Plasma of glucose and urea-N concentration were significantly (p<0.05) elevated from 1 h to 6 h after feeding, otherwise total protein in plasma was declined (p<0.01) at 6 after feeding.

• Aerospace Engineering and Technology
• /
• v.12 no.2
• /
• pp.83-90
• /
• 2013

In this paper, the energy flows related to cryogenic propellant tank ullage were understood and pressurization efficiency of the tank was calculated using propellant feeding test data with the help of calculation program. The related energy flow terms and calculation method of each terms were described. Three test data of different tank pressure and incoming pressurant temperature were used. Under the test conditions, the pressurization efficiency was low in the range of 13.9%~19.3%. The proportion of energy loss to the incoming pressurant energy was in the range of 55.2%~67.6%. The energy loss to the propellant tank wall was the biggest one. If the temperature of incoming pressurant was the same, the rates of each energy flows to the incoming energy were almost the same regardless of the propellant tank pressure. The collapse factor of propellant tank was calculated using test data, and the relation of it to the heat loss rate was observed.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.27 no.5
• /
• pp.295-303
• /
• 2015

The eigenfunction expansion method is appled for the wave scattering by a vertical slotted, where both the inertial and quadratic drag terms are involved. Quadratic drag term representing the energy loss is linearized by the application of socalled equivalent linearization. The drag coefficient, which was empirically determined by Yoon et al.(2006) and Huang(2007) is used. Analytical results are verified by comparison to the experimental results conducted by Kwon et al.(2014) and Zhu and Chwang(2001). Using the developed design tool, the effect of energy loss by a vertical slotted wall is estimated with various design parameters, such as porosity, submergence depth, shape of slits and wave characteristics. It is found that the maximum value of energy loss across the slotted wall is generated at porosity value less than P = 0.1. The present solutions can provide a good predictive tools to estimate the wave absorbing efficiency by a slotted-wall breakwater.

• Journal of Energy Engineering
• /
• v.20 no.4
• /
• pp.303-308
• /
• 2011

The present study has been carried out to predict the heat transfer characteristics of reverse heat loss method for a residential refrigerator by using numerical analysis and corresponding experiment. From the measured values of temperature and heat input, one can conclude that, the temperature inside the refrigerator has a nearly linear relationship with heat input. The effect of gasket heat loss was examined with the change of thermal conductivity of gasket region. The appropriate thermal conductivity of gasket region was acquired from the comparison of heat losses with the experimental result and numerical analysis. The result of calculated heat losses had accuracy within 1.8% error with the experimental result. With the selected thermal conductivity of gasket region, the effectiveness of reverse heat loss method was examined with the change of thermal conductivity of vacuum insulation panel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.824-828
• /
• 2007

In this paper Statistical Energy Analysis has been considered to predict middle, high frequency air borne interior noise. PIM method is used for verification. Damping loss factor and coupling loss factor have been derived from the response(SPL) of sub systems when the power is applied. The airborne SEA model of vehicle is modeled through AutoSea2. Insulation material's absorption coefficient and transmission loss are acquired from closed form solution and experiment.

• Journal of KSNVE
• /
• v.7 no.4
• /
• pp.589-596
• /
• 1997

A energy equation for a thin plate and surrounding fluid is derived. The equation essentially determines the relation between internal loss of thin plate, energy of acoustic radiation, and structure intensity. We attempted to use this relation to measure internal loss of thin plate. The significance of this approach is that internal loss at any point of a thin plate can be measured. The quality of this measure is dicated by the accuracy of associated measurement systems such as structure and acoustic intensity measurements. A strain gauge bridge system has been developed to measure structure intensity of thin plate. Its performance is tested by experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.166-171
• /
• 2002

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.323.1-323
• /
• 2002

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system usiong 4-microphone impedance tube is proposed, based on the idea calculating the full transger matrix of the acoustical sample to test. The theoretical backgroung and measurement system are introduced, and finally the measurement results are verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.658-661
• /
• 2003

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.179-180
• /
• 2015

The task of measuring losses becomes more challenging with ever increasing efficiencies and operating frequencies in power electronics applications. Generally, the process of traditional switching loss calculation in flyback converter is very complicated. MOSFET drain-source voltage and current waveforms are needed to calculate switching loss. However, as we know in switched capacitor converter, switching loss can be easily calculated by charge and energy conservation law with known initial and final capacitor voltages. In this paper, the same method is applied to fly-back converter switching loss analysis to simplify calculation procedure.