본 연구에서는 건열처리를 통해 알팔파 종자에 접종된 Bacillus cereus ATCC 12480, Listeria monocytogenes ATCC SSA81, Staphylococcus aureus ATCC 6538, Escherichia coli O157:H7 ATCC 43894, Salmonella Typhimurium ATCC 14028을 발아율에 영향 없이 불활성화 시키는 조건(65oC 에서 21일, 70oC에서 16일, 75oC에서 10일, 80oC에서 7일)을 조사하였다. 알팔파 종자를 6-7 log CFU/g 수준으로 접종 하고 65, 70, 75, 80oC로 건열처리 한 후, 발아율을 확인 하였다. 알팔파 종자의 발아율은 시장에 유통되고 있는 알 팔파 새싹의 발아율 기준인 70%로 설정하였다. 알팔파 종 자에서 B. cereus는 65oC에서 21일, 70oC에서 18일, 75oC 에서 14일, 80oC에서 4일, Listeria monocytogenes는 65oC에서 21일, 70oC에서 18일, 75oC에서 12일, 80oC에서 7일, S. aureus는 65oC에서 18일, 70oC에서 18일, 75oC에서 11 일, 80oC에서 4일, E. coli O157:H7은 65oC에서 21일, 70oC 에서 18일, 75oC에서 12일, 80oC에서 6일, Sal. Typhimurium 은 65oC에서 24일, 70oC에서 22일, 75oC에서 14일, 80oC 에서 7일 이상 건열처리 하였을 때 완전히 불활성화 되었 다. 모든 균주는 65oC에서 80oC로 온도가 상승할 때 특정 온도에서 세균의 90%를 죽이는 데 필요한 시간인 D-값 (R2=0.5656−0.7957)이 유의미하게 감소하였다(P<0.05). 80oC 에서 7일간 건열처리 하였을 때 발아율이 70% 미만으로 감소하였기 때문에 75oC에서 14일간 건열처리 하는 것이 알팔파 종자의 안전성을 확보하는데 있어 가장 효과적인 방법이다. 이 연구는 알팔파 종자의 안전성을 확보하고 일 정한 품질의 새싹을 생산하는데 기초자료로 이용될 것으 로 기대된다.
In this paper, a heat exchange system using cooling dehumidification and mixing process was proposed as an experimental study for a white smoke reduction heat exchanger system under winter condition. The white smoke reduction heat exchange system is divided into an EA part, SA part, W part and mixing zone. For the operating conditions, three types (Cases 1, 2, and 3) were selected depending on whether EA fan, SA fan, and A-W heat exchanger were operated. In addition, in order to visualize the white smoke exhausted from the mixing zone, it was photographed using CCTV. In order to investigate the performance of the white smoke reduction heat exchange system, the temperature reduction rate and absolute humidity reduction rate of EA and the heat recovery rate of W were calculated. The temperature change of EA and SA according to operating conditions was most effective in Case 3, and the temperature and absolute humidity at the outlet of the mixing zone were greatly reduced. From the results of the white smoke visualization, it was confirmed that the white smoke generation mechanism was different depending on the operating conditions, and the amount of white smoke generation was greatly reduced.
도시화로 인한 열섬현상은 매년 심각해지고 있으며 도시 내의 온도증가로 인한 피해 또한 증가되고 있다. 최근 도시녹지 조성을 통한 온도저감이 도시열섬현상의 해결방안으로 부각되고 있다. 본 연구에서는 도시 공원녹지의 지형적 특징에 따른 주변 온도저감 효과를 분석하였다. 이를 위해 위성영상을 통해 서울시의 지표면 온도를 구축하였으며 서울시 내의 공원녹지와 녹지 주변에 대한 온도 분석을 실시하였다. 또한 유사한 주변 환경을 가진 공원녹지들을 추출하 고 각 녹지의 지형 요소에 따른 주변 온도저감 효과 분석을 실시하였다. 그 결과 녹지의 고도범위, 부피, 경사도가 증가함에 따라 주변 온도저감효과도 증가하는 것으로 나타났다. 이러한 결과는 향후 공원조성 시 지형적 요소 고려 뿐만 아니라 도시계획 차원에서의 바람길 조성 정책에도 영향을 줄 수 있을 것으로 보인다.
PURPOSES : This study aims to reduce the urban heat island phenomenon via utilization of porous asphalt pavements.
METHODS : One of the many known functions of porous asphalt is that it reduces the urban heat island phenomenon. Indoor experiments
were conducted to compare the surface temperature of sprinkled dense-graded and porous asphalt and outdoor experiments were conducted
to verify the difference between the two asphalt pavements under external conditions.
RESULTS : The results of the indoor experiment demonstrated that the temperatures of the two pavements were similar and that the porous
asphalt pavement exhibited low temperature when sprinkled; the temperature of the porous asphalt was approximately 2 °C lower than that
of the dense-graded asphalt pavement. The results of the outdoor experiment showed that the peak temperatures of the two pavements were
approximately the same as usual. However, it was confirmed that the surface temperature of the porous asphalt pavement at night after sunset
was lower than that of the dense-graded asphalt pavement and that the peak temperature dropped for approximately 1~2 days after the rainfall..
CONCLUSIONS : Porous asphalt pavement has a lower surface temperature than normal dense-graded asphalt pavement, under the
presence of moisture in the pavement. In addition, it was confirmed that the lower surface temperature of the porous asphalt pavement is due
to the low heat emission of the pavement at night. Accordingly, it is believed that the application of the porous asphalt pavement will not only
have known effects but also significant impacts on the reduction of urban heat island phenomena.
The estimation of heat source model is very important for heat transfer analysis with finite element method. Part I of this study used adaptive simulated annealing which is one of the global optimization algorithm for anticipating the parameters of the Goldak model. Although the analysis with 3D model which depicted the real situation produced the correct answer, that took too much time with moving heat source model based on Fortran and Abaqus. This research suggests the procedure which can reduce time with maintaining quality of analysis. The lead time with 2D model is reduced by 90% comparing that of 3D model, the temperature distribution is similar to each other. That is based on the saturation of heat transfer among the direction of heat source movement. Adaptive simulated annealing with 2D model can be used to estimate more proper heat source model and which could enhance to reduce the resources and time for experiments.
In this study, a white smoke reduction simple prediction model of white smoke reduction heat exchange system was developed by using EES. In order to verify the reliability of the EES model, it was compared with the computational results. The developed EES predictive model was used to calculate the temperature and absolute humidity of the mixed SA and EA according to the change of cooling water capacity, flow rate ratio of SA/EA, and SA inlet temperature. The difference between final temperature and absolute humidity at the outlet of the mixer calculated by computational analysis and EES was within 1.4% and 3.6%. As the cooling water capacity and the inlet flow rate ratio increased, and as the inlet air temperature decreased, the temperature and absolute humidity of the mixer decreased. The most influential factor in the white smoke reduction effect among the design variables of the white smoke reduction heat exchange system was the flow rate ratio of SA/EA.
The results of internal temperature. productivity and immunity analysis of the laying hen house by the thermal environment and the supply of cold drinking water were as follows. The external temperature was changed from the minimum of 18℃ at night and the maximum of 36℃ during the day, and the internal temperature of the laying hens varied from 20~31℃. Thermal imaging analysis showed that the body temperature of the laying hen decreased by 2.4℃ with the supply of drinking water. The laying hen amount increased 2.36g and laying hen rate increased 3.62%p. Albumin increased 6.1%, decreased AST 15%, and decreased cholesterol 12.7%. Immune activators increased and T cells and B cells increased to increase immunity.
In this study, the temperature, the absolute humidity, and the turbulent flow characteristics of exhaust air and supply air in the mixer were studied while changing the shape of the mixer of the white smoke reducing heat exchange system. Using Solidworks, the mixer of the white smoke reduction heat exchange system was created by 3-D model. Also, the mixed flow of supply air and exhaust air inside the mixer under the uniform inlet conditions was computed, using the solidworks flow simulation. Two types of improvement models were selected by using a perforated plate and a guide vane as a turbulent mixing flow control method of the mixer. The mean temperature and mean absolute humidity of the mixture were greatly decreased according to the internal shapes of Case 1, 2, and 3. The temperature difference between the inlet and outlet of the mixer Case 3 was 26℃. The exit temperature and absolute humidity reduction rates of Case 3 were 26.2% and 48.1%, respectively, compared with Case 1.
In this study, the characteristics of the heat flow on SA(supply air) side of the white smoke reducing heat exchange system according to the change of SA velocity were analyzed in the winter condition (outside temperature 0℃). Also, the mixing process of SA and the EA(exhaust air) is presented in the psychrometric chart to confirm the possibility of reducing white smoke. Solidworks flow simulation was used to analyze the heat flow on the heat exchange system under uniform conditions. As the inflow velocity of SA increased, the temperature of SA decreased due to the convective heat transfer improvement due to the active flow in SA system. And the outlet temperature and absolute humidity of the mixing zone decreased significantly. At SA velocity 7 m/s, the outlet temperature and absolute humidity decreased to about 58% and 82%, respectively.
In this study, effects of reducing white smoke at a heat exchange system for white smoke reduction were studied in the winter season. For this purpose, the heat transfer processes on the exhaust air were investigated by Solidworks. Five wave heat exchangers of air-to-air and air-to-water type were applied for the exhaust air heat recovery. The analytical condition of the exhaust air was fixed and the computational analysis was performed according to the change of SA(supply air) inlet velocities. In order to evaluate the performance of the heat exchange system for white smoke reduction, W(water)/SA recovered capacities and the temperature/ absolute humidity reduction rate were calculated. As SA inlet velocity increased, the exit temperature and absolute humidity of the mixing zone were reduced by up to about 40℃ and 0.12kg/kg respectively. Also, W/SA recovered capacities increased linearly up to about 35%.
In the present study, the white reduction system was designed and manufactured to evaluate the performance of a heat exchange system using a wave heat exchanger. The reducing effect of white smoke and the amount of heat recovered from cooling water were investigated experimentally using the cooling and dehumidifying method. The white smoke reduction system consists of two parts; the generating part and the reducing part of white smoke. Experimental conditions on EA(exhaust air) and SW(supply water) were fixed. And the outlet temperature and absolute humidity of EA were measured according to inlet velocity of SA(supply air). The outlet temperatures and absolute humidities of EA gradually decreased as inlet velocities of SA increased. From the experimental results, we can see that the absolute humidity reduction rate of EA was max. 84%, and the heat recovery rate of SW was max. 42%.
This study was conducted to develop a heat interception permeability aggregate pavement material that resists increase of air temperature and has permeability by decreasing pavement temperature of city in summer. For this study, a heat interception polymer binder mixed with heat interception material and polyurethane binder. And the study made heat interception permeability aggregate pavement material by mixing heat interception polymer binder. Using the materials, the study conducted flexural strength test and temperature reduction effect experiment. As the result, flexural strength was 5.43MPa average and the temperature reduction effect was effective up to maximum 16 degrees Celsius compared to current asphalt concrete.
The objectives of this study are to investigate the effect of plant type on the roof of a model building on the temperature of the interior space, and to provide the suitable plant species for a green roof. On the roof of scaled model building, grass (GR: Zoysia japonica), sedum (SE: Sedum makinoi Aurea), maekmundong (MM: Liriope platyphylla), and jasanhong (JH: Rhododendron schippenbachii) was planted. From June 28 to August 28, i.e., for 63 days, the internal and external temperature of the model building and the light intensity were measured and compared with the control model building (CON: no plant and substrate on the roof). With increased global radiation, the maximum temperature was increased from 28.2℃ to 51.74℃ for CON, from 27.2℃ to 47.7℃ for GR, from 27.7℃ to 49.3℃ for SE, from 27.9℃ to 48.3℃ for MM, from 27.5℃ to 48.9℃ for RD, whereas the outside temperature increased between 25.5℃ and 34.6℃. A positive linear relationship was observed between global radiation and the internal temperature (r=0.987-0.989) and hence, the temperature difference between the internal and external model building (ΔT) was larger with increased radiation. A positive linear relationship was shown between light intensity and ΔT at difference radiation levels. The regression coefficient was estimated as 0.99-1.00℃/[100W/m2] under 500 J/cm2, 1.10-1.15℃/[100W/m2] at averaged radiation 1,800J/cm2, whereas the large decrease in the coefficient, i.e., 0.76-0.86℃ /[100W/m2] was observed for above 1,800J/cm2 radiation level. The ΔT per unit of light intensity observed a significantly different between treatments. With the planted grass on the roof of the model building, the lowest ΔT per unit solar radiation was observed, which means that the covered roof with grass causes the building internal temperature to be less affected by the sun radiation.
In this study, the heat transfer characteristics of pilot wave heat exchanger for white smoke reduction system was investigated. The performance of the wave and honeycomb heat exchanger combined with the first stage, second stage and third stage was tested using a calorimeter. Air and water inlet/outlet temperature and flow rate, pressure drop and dehumidification amount were measured to compare the heat transfer performance according to the type and the combination of heat exchanger. The heat transfer rate and dehumidification amount of the wave heat exchanger were higher than that of the honeycomb heat exchanger, and the pressure drop was low. As the stage increased, the heat transfer rate and the increase of the dehumidification amount were more pronounced, and the pressure drop linearly increased. The wave heat exchanger had a lower flow resistance than the honeycomb heat exchanger with the honeycomb structure and had a higher heat transfer effect due to the convection, so the water outlet temperature was higher in the wave heat exchanger.
본 연구는 환경 친화적인 새싹채소류의 고품질화를 위한 경제적이고 효율적인 살균기술을 개발할 목적으로 국내산 적무 종자의 다양한 열처리 방법에 따른 발아율과 미생물 저감효과를 조사하였다. 열수처리는 60, 65, 70, 75, 80, 90℃에서 각각 30, 60초간 실시하였고, 건열처리는 70, 80, 90, 100℃에서 5분간 실시하였다. 열수 처리에 따른 미생물의 제어효과는 시간에 따른 유의적인 차이는 보이지 않았으나, 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 70℃ 이상의 온도에서 총세균수는 3 logs 이상의 감소를 보였으며, L. monocytogenes는 검출되지 않았다. 건열처리는 온도변화에 따른 유의적인 차이를 나타내었다 (p<0.001). 100℃에서 5분간 처리한 후 총세균과 L.monocytogenes 수는 3 logs 이하 감소하였다. 열수처리에 따른 발아율의 변화는 처리 전과 후 모두 시간에 따른 유의적인 차이는 보이지 않았으나, 75℃ 이상의 온도에서 온도증가에 따라 유의적으로 감소하였다(p<0.001). 한편, 열수처리 후 침지시킨 종자에서 발아가 더 촉진되는 것으로 나타났다. 건열처리에 따른 발아율은 80℃ 이상의 온도에서 온도 증가에 따라 유의적으로 감소하였다(p<0.001). 건열처리한 후 증류수에 3시간 침지시킨 종자의 발아율은 90℃ 이상의 온도에서 유의적으로 감소하였다(p<0.05). 결론적으로 적절한 열처리는 75℃, 30분 이상의 열수처리하는 방법으로, 적무 새싹채소의 종자의 미생물학적 안전성을증가시킴과동시에발아율을증가시키는것으로판단된다.