• International Journal of High-Rise Buildings
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• v.8 no.2
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• pp.101-106
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• 2019

Assessing the energy performance of supertall buildings often does not consider variations in energy consumption due to the change of environmental conditions such as temperature, pressure, and wind speed associated with differing elevations. Some modelers account for these changing conditions by using a conventional temperature lapse rate, but not many studies confirm to the appropriateness of applying it to tall buildings. This paper presents and discusses simulated annual energy consumption results from a 600 m tall skyscraper floor plate located in Dubai, UAE, assessed using ground level weather data, a conventional temperature lapse rate of $6.5^{\circ}C/km$, and more accurate simulated 600 m weather data. A typical office floorplate, with ASHRAE 90.1-2010 standards and systems applied, was evaluated using the EnergyPlus engine through the OpenStudio graphical user interface. The results presented in this paper indicate that by using ground level weather data, energy consumption at the top of the building can be overestimated by upwards of 4%. Furthermore, by only using a lapse rate, heating energy is overestimated by up to 96% due to local weather phenomenon such as temperature inversion, which can only be conveyed using simulated weather data. In addition, sizing and energy consumption of fans, which are dependent both on wind and atmospheric pressure, are not accurately captured using a temperature lapse rate. These results show that that it is important, with the ever increasing construction of supertall buildings, to be able to account for variations in climatic conditions along the height of the building. Adequately modeling these conditions using simulated weather data will help designers and engineers correctly size mechanical systems, potentially decreasing overall building energy consumption, and ensuring that these systems are able to provide the necessary indoor conditions to maintain occupant comfort levels.

• Applied Biological Chemistry
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• v.31 no.3
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• pp.298-307
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• 1988

The kinds of volatiles in tomato fruits during storage were increased with the period of climacteric rise. The increasing and decreasing rate of their contents were slower under subatmospheric pressure-low temperature (SAP-L) than under normal atmospheric pressure-normal temperature (NAP-N). High contents of 2-hexanone, n-pentanol, and ethanol were decreased at the early period of storage and then increased. The content of n-octanol and furfural were increased, while that of n-butanol, cyclohexanone, and phenylacetaldehyde was decreased during storage. On the other hand, the content of trans, trans-2,4-decadienol, benzyl alcohol, and 2-heptanone was not changed during storage.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.204-210
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• 2014

Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.

• Design & Manufacturing
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• v.2 no.4
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• pp.37-43
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• 2008

Supplementary features in injection molded products, which are boss, rib and snap fit, are mainly located in the products. These features might make molding flow improper in injection processing and consequently give rise to some of molding troubles such as short shot and hesitation. The sink mark on boss parts is generated by the volumetric shrinkage that is caused by both the molding thickness and the closed boss height. The volumetric shrinkage is affected by packing pressure and its amount tends to decrease by increasing the packing pressure. The packing pressure can therefore increase flow rate to a boss part and causes the sink mark depth to increase. As the molding thickness and the closed boss height in the boss part can increase the part volume, these may yield bad solidifying and also extend the molding cycle. In this paper, both the injection molding test and the flow analysis were carried out to investigate the effect of sink marks generated in the boss part of injection molded products.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.202-212
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• 2008

A three-dimensional computation was conducted to understand effects of the low Reynolds number on the loss characteristics in a transonic axial compressor, Rotor67. As a gas turbine becomes smaller in size and it is operated at high altitude, the operating condition frequently lies at low Reynolds number. It is generally known that wall boundary layers are thickened and a large separation occurs on the blade surface in axial turbomachinery as the Reynolds number decreases. In this study, it was found that the large viscosity did not affect on the bow shock at the leading edge but significantly did on the location and the intensity of the passage shock. The passage shock moved upstream towards leading edge and its intensity decreased at the low Reynolds number. This change had large effects on the performance as well as the internal flows such as the pressure distribution on the blade surface, tip leakage flow and separation. The total pressure rise and the adiabatic efficiency decreased about 3% individually at the same normalized mass flow rate at the low Reynolds number. In order to analyze this performance drop caused by the low Reynolds number, the total pressure loss was scrutinized through major loss categories such as profile loss, tip leakage loss, endwall loss and shock loss.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.72-78
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• 2003

In the present paper, computational studies on the hydrodynamic behavior of the inducer for the rocket-engine turbopump are presented including the effect of the mass flow rate. As the mass flow rate is increased, the inducer showed better performance with weak back flows which may have deleterious effects upon the anti-cavitation ability. But the adopted inducer showed low head rise with high volume flow rates, which may be caused by the small passage area near the trailing edge. The static pressure distributions at the shroud surface are compared with experimental results showing very good agreements except near the leading edge where strong back flows are present. The overall performance of the inducer such as, efficiency, head rise is also compared with experiments. The computational results are generally in good agreements with experimental ones near the design point, but two results show discrepancy at the high flow rate.

• Fire Science and Engineering
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• v.25 no.4
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• pp.103-109
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• 2011

In this study, we calculated the smoke movement at the fire area of the refuge floor which has the refuge safety area in case of fire in the high rise building by using a computational fluid dynamics (CFD) code of FLUENT (ver. 13.0). The buoyancy plume was applied using the temperature and flow velocity which represent 10 MW heat release rate in order to describe the fire, and the smoke movement was predicted using a species conservation equation. The pressurization system of smoke control was adopted with smoke control damper in refuge safety area, at the result, it is confirmed that the damper capacity was enough to smoke control in which the flow rate of supply was applied 25 $m^3/s$ in the case of the door at fire area opened only, and 50 $m^3/s$ in the doors at the fire area and lobby both opened case. They were satisfied in NFSC 501-A. Even though the door of fire area closed, there were smoke leakages at the gap between the door and wall. In addition, the refugee could be isolated in the fire area when the door of fire area closed during smoke control in the case of using the high damper flow rate of supply, 50 $m^3/s$. Therefore the proper damper flow rate of supply are needed in order to prevent the damage of refugee and this study proposes the suitable condition of damper capacity according to refuge scenario.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.9
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• pp.790-798
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• 2007

An experimental study was performed to investigate the effects of mixing quality, inlet pressure, nozzle diameter on CO, NO emission and radiation characteristics in porous ceramic fiber radiant burners. Observations of combustion characteristics occurring inside the burner system which was insulated fiber mat, were investigated by measuring emission and radiation characteristics. Combustion was achieved at the firing rate of $88{\sim}99\;kcal/hr$, inlet pressure of $100{\sim}250mmH_2O$. The fiber burner exhibit significant both spectral intensity peaks in the bands at $2.5{\mu}m\;and\;4.0{\mu}m$ relatively. There is a small difference in the variable mixing tube. However spectral intensity increased with the firing rate. CO emissions were found to be strongly dependent on the operating conditions. There was a tendency that CO concentration increased as the firing rate increases. the reason for rise of CO concentration is that is becomes it the relatively rich condition. Relatively low NO emission was observed for the whole operating range. The NO concentration is maximal at the firing rate of approximately 2850 kcal/hr and an air ratio of about 1.

• Journal of the Korean Ceramic Society
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• v.44 no.9
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• pp.529-535
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• 2007

Calcium oxide has been used as a demolition agent in fracturing rocks and old concrete structures, etc. With the agent, demolition work can be done in safety without a noise, vibration and any other pollution, since high expansive pressure is obtained gradually by only mixing the agents with water and pouring the slurry into boreholes. But application of the non-explosive demolition agent is a time-consuming job, especially in winter. Essentially, this problem is related to the reaction rate of calcium oxide with water. This study examines the influence of additives such as cement and anhydrite on expansion pressure of calcium oxide at different curing temperatures. The expansion pressure of calcium oxide began to increase steadily with the rise of the curing temperature. When mixing calcium oxide alone with water, blown-out shot occurred. But as additives were added to calcium oxide, the reaction of calcium oxide delayed and the expansion pressure showed gradual increment. Especially, anhydrite showed a superior delaying effect than cement on the reaction of calcium oxide.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.10027-10031
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• 2014

Background: We investigated the risk of cancer mortality according to obesity status and metabolic health status using sampled cohort data from the National Health Insurance system. Materials and Methods: Data on body mass index and fasting blood glucose in the sampled cohort database (n=363,881) were used to estimate risk of cancer mortality. Data were analyzed using a Cox proportional hazard model (Model 1 was adjusted for age, sex, systolic blood pressure, diastolic blood pressure, total cholesterol level and urinary protein; Model 2 was adjusted for Model 1 plus smoking status, alcohol intake and physical activity). Results: According to the obesity status, the mean hazard ratios were 0.82 [95% confidence interval (CI), 0.75-0.89] and 0.79 (95% CI, 0.72-0.85) for the overweight and obese groups, respectively, compared with the normal weight group. According to the metabolic health status, the mean hazard ratio was 1.26 (95% CI, 1.14-1.40) for the metabolically unhealthy group compared with the metabolically healthy group. The interaction between obesity status and metabolic health status on the risk of cancer mortality was not statistically significant (p=0.31). Conclusions: We found that the risk of cancer mortality decreased according to the obesity status and increased according to the metabolic health status. Given the rise in the rate of metabolic dysfunction, the mortality from cancer is also likely to rise. Treatment strategies targeting metabolic dysfunction may lead to reductions in the risk of death from cancer.