The variations of internal temperature, relative humidity (RH) and gas concentration in the pallet modified atmosphere package (MAP), using polyamide (PA) film and linear low density polyethylene (LLDPE) film, were investigated to extend the shelf life of tomatoes and paprikas. The temperature and RH inside the MAP were higher than that in the cold room, but there was no water condensation inside the MA film. The ethylene concentration in the MAP was maintained below 10 ppm. Oxygen level was stabilized at 2 to 5% during the storage and carbon dioxide level was also stabilized at 15 to 20%. The weight loss of the MAP tomatoes and paprikas was lower than that of the control because the RH in the pallet MAP was higher than that of the cold room. The fungal decay rate in the pallet MAP was also lower than that in the control due to a low oxygen concentration rate. There were no significant differences in the soluble solids, titratable acidity and Hunter’s color, but differences did exist in the hardness between the MAP and the control. So, this pallet MAP method was effective at extending the shelf life of tomatoes and paprikas considering the weight loss, fungal decay and hardness.

In this study, we utilize the cross and partial correlation analyses in order to investigate the dependence of power energy consumption on the temperature. To this end, we use a time series data that consists of three attributes : an hourly measured electric power consumption, temperature, and humidity. We, in particular, divide the yearly data into monthly base, and estimate the cross correlation coefficients between all possible pairs of attributes for each monthly based data. We found that temperature and power consumption are negatively correlated in the winter; positively correlated in the summer. A similar trend was found between humid and power consumption. This implies that when temperature or humidity is relatively high or low, the power consumption increases due to the cooling and heating system at work. In contrast, the correlation between temperature and humid behaves differently from those between temperature and power consumption. These results can be used to effectively manage the power system.

We fabricated dual-phase free-standing polymeric membrane for high performance CO2/N2 separation, introducing amphiphilic, CO2-philic copolymer via one-step free radical polymerization, or (2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate)-graft-poly(oxyethylene methacrylate) (PBE). PBE filler partially interacts with Pebax polymer matrix to generate the interconnected CO2 philic network, exhibiting a microphase-separated, or dual-phase behavior in Pebax matrix. The performance of CO2/N2 separation was increased according to the PBE content, with the maximum selectivity at 5 wt%. The enhancement of Pebax/PBE CO2-philic membrane was attributed to the formation of CO2-philic channel consisting of ether oxygens and triazole groups. The best performance was CO2 permeability of 175.3 Barrer and CO2/N2 selectivity of 48.2.

As ZIF materials have their unique properties such as high surface area, tunable pore structure, thermal and chemical stability, they can be used in gas separation. In this work, we synthesized ZIF-8 seed layer by combining ZnO coating on the support and the conversion synthesis of ZnO layer in H-mIm solution to ZIF-8 layer, followed by the secondary growth synthesis for ZIF-8 membranes. The effect of solvent on conversion seeding had been investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate. The optimum solvent combination (water and methanol) was studied according to the thickness of the ZnO layer used in the conversion seeding. The obtained membranes showed excellent performance for propylene/propane gas separation. The thicker the ZnO layer, the lower the permeability.

General D-glass(Dielectric glass) fibers are adaptable to PCBs(Printed circuit boards) because they have a low dielectric constant of about 3.5~4.5. However, very few papers have appeared on the physical characteristics of D-glass fibers. D-glass fibers were fabricated via continuous spinning process using bulk D-glass. In order to fabricate the D-glass, raw materials were put into a Pt crucible, melted at 1650℃ for 2 hrs, and then annealed at 521 ± 10℃ for 2 hrs. We obtained transparent clear glass. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of 1368℃ to 1460℃, while the winder speed was between 100 rpm and 200 rpm. We investigated the physical properties of the D-glass fibers. The average diameters of the glass fibers were measured by optical microscope and FE-SEM. The average diameters of the D-glass fibers were 21.36 um at 100 rpm and 34.06 um at 200 rpm. The mechanical properties of the fibers were confirmed using a UTM(Universal materials testing machine). The average tensile strengths of the D-glass fibers were 467.03 MPa at 100 rpm and 522.60 MPa at 200 rpm.

We investigate the effect of the modification of cellulose acetate propionate as an organic vehicle for silver paste on solar cell efficiency. For the modification of cellulose acetate propionate, poly(ethylene glycol) is introduced to the hydroxyl groups of a cellulose acetate propionate backbone via esterification reaction. The chemical structure and composition of poly(ethylene glycol) functionalized cellulose acetate propionate is characterized by Attenuated total reflectance Fourier transform infrared, 1H nuclear magnetic resonance, differential scanning calorimetry and thermogravimetric analysis. Due to the effect of structural change for poly(ethylene glycol) functionalized cellulose acetate propionate on the viscosity of silver paste, the solar cell efficiency increases from 18.524% to 18.652 %. In addition, when ethylene carbonate, which has a structure similar to poly(ethylene glycol), is introduced to cellulose acetate propionate via ring opening polymerization, we find that the efficiency of the solar cell increases from 18.524% to 18.622%.

In this study, the CFD analysis was performed by changing the geometry of coil-tube diameter ratio, coil winding number, coil pitch, and cross section of the tube to investigate the heat flow characteristics of forced convection in a helical coil-tube heat exchanger using RSM (Reynolds Stress Model). As a result, the secondary flow was developed in the tube caused by the influence of centrifugal force. It improved the heat transfer on the outer side of the tube, but on the inner side was not performed well. And the temperature rose locally in the tube region. Also the pressure drop in the tube was proportional to the diameter ratio of the coil-tube and the inlet velocity, and it was found that pressure drop and friction factor were inversely proportional. When the coil winding number and coil pitch were increased, it affected heat transfer in the low speed range of 0.1 ~ 0.2 m/s, but did not affect the flow condition after this range.

The TRM method applied in this study is a method aiming at long span and low girder hight of the temporary bridge. When the preload is introduced to the girder member and the preload is removed after by welding the stiffener, a prestress is introduced through the stiffener to increase the load capacity of the member. Therefore, in this study, the structural performance improvement through the application of the TRM method was verified experimentally by the bending tests of the specimens with and without the TRM method.

본 연구는 경북지역 거세 한우의 출하체중에 따른 도체 특성 및 부분육 생산량을 조사하여 고기의 생 산성을 도체로부터 평가하기 위하여 실시하였다. 경북지역 거세 한우 51두를 도착체중 700kg미만, 701~750kg, 751~800kg, 801~850kg, 850kg초과 5그룹으로 나누어 가공단계별 중량변화, 도체규격, 대분할 부위 생산량 및 수율, 소분할 부위 생산량 및 수율, 부산물 생산량 및 수율을 조사하였다. 가공 단계별 중량변화는 한우의 출하체중이 증가함에 따라 온도체중, 냉도체중, 대분할육, 소분할육, 뼈량, 지방량이 증가하였다. 도체규격은 한우의 출하체중이 증가함에 따라 전장, 전사분체장, 흉장, 경폭, 흉 폭, 퇴폭, 흉위, 퇴위, 흉후가 증가하였다. 부산물 생산량은 한우의 출하체중이 증가함에 따라 머리, 앞 족, 뒷족, 가죽, 간, 소장, 배지방, 생식기, 신장, 기타지방량이 증가하였다. 도체부산물은 한우의 출하 체중이 증가함에 따라 사골, 꼬리반골, 도가니, 마구리, 잡뼈, 갈비뼈량이 증가하였다.

ZIFs (Zeolitic imdazolate frameworks)은 높은 화학적⋅열적 안정성, 높은 비표면적과 조절 가능한 기공구조로 최근 분리막 소재로 큰 관심을 받고 있다. 본 연구에서는 두 가지 종류의 다공성 지지체(α-alumina 및 YSZ)를 사용하여 in situ 성장법으로 ZIF-8 분리막을 합성하고, H2/CO2 기체 투과 특성을 조사하였다. 결함 없는 ZIF-8층을 합성하는데 있어, 기공이 작은 YSZ 지지체는 α-alumina 지지체 보다 더 적은 시간이 요구되었다. 합성시간이 3 h인 경우, α-alumina 및 YSZ 지지체 위에 형성된 ZIF-8 분리막은 약 10 정도의 H2/CO2 선택도를 보였다.

PURPOSES: This study develops various models that can estimate the pattern of road surface temperature changes using machine learning methods. METHODS : Both a thermal mapping system and weather forecast information were employed in order to collect data for developing the models. In previous studies, the authors defined road surface temperature data as a response, while vehicular ambient temperature, air temperature, and humidity were considered as predictors. In this research, two additional factors-road type and weather forecasts-were considered for the estimation of the road surface temperature change pattern. Finally, a total of six models for estimating the pattern of road surface temperature changes were developed using the MATLAB program, which provides the classification learner as a machine learning tool. RESULTS: Model 5 was considered the most superior owing to its high accuracy. It was seen that the accuracy of the model could increase when weather forecasts (e.g., Sky Status) were applied. A comparison between Models 4 and 5 showed that the influence of humidity on road surface temperature changes is negligible. CONCLUSIONS: Even though Models 4, 5, and 6 demonstrated the same performance in terms of average absolute error (AAE), Model 5 can be considered the optimal one from the point of view of accuracy.