Yuzu (Citrus junos) undergoes traditional processing to create preserved yuzu with a sugar content of 50%. This study aimed to produce low-sugar yuzu syrup using artificial or natural sweeteners instead of sugar. Among artificial sweeteners, maltitol showed minimal browning and lack of deposition at high temperatures. The addition of xanthan gum (0.2%) and carboxymethyl cellulose (0.2%) resolved the issue of layer separation and viscosity decrease of yuzu syrup. Alternatively, grain syrup, a natural sweetener, improved viscosity and homogeneity without the additives. Yuzu syrups were developed using yuzu juice and preserved yuzu, with maltitol (20~40%) or grain syrup (50~70%) as the sweetener. Yuzu syrups containing 35% maltitol (M35) or 55% grain syrup (G55) had less than 5% and 10% free sugar, respectively. These syrups exhibited taste patterns similar to commercial yuzu syrup in analysis using an electronic tongue. Furthermore, M35 and G55 contained yuzu flavonoids at concentrations of 19.82 mg/g and 24.09 mg/g, respectively. Antioxidant activity (DPPH, ABTS radical scavenging) of M35 and G55 was equivalent to 10.55, 17.59 mg/100 g of Vitamin C and 97.39, 33.92 mg/100 g of Vitamin C, respectively. Consequently, M35 and G55 offer promising alternatives to preserved yuzu, providing low-sugar yuzu syrups enriched with functional ingredients.

본 연구에서는 중공사형 이산화탄소 분리막 모듈을 사용하여 수소개질기 배가스로부터 이산화탄소 포집을 목적 으로 한 분리막 공정 최적화 연구를 진행하였다. 랩스케일의 소형 분리막 모듈을 사용하여 혼합기체를 대상으로 이산화탄소 순도 90% 및 회수율 90%을 달성하는 2단 공정 조건을 도출하였다. 막 면적이 정해진 모듈의 분리막 공정에서는 스테이지-컷, 주입부 및 투과부 압력에 따라서 포집 순도 및 회수율이 모두 다르게 나타나기 때문에 운전 조건에 대한 최적화가 필수적이 다. 본 연구에서는 다양한 운전 조건에서 1단 분리막에서 보이는 공정 포집 효율의 한계를 확인하고, 높은 순도와 회수율을 동시에 달성하기 위한 2단 회수 공정을 최적화하였다.

PURPOSES : In this study, the resources and energy consumed to produce hot mix asphalt mixtures and hot mix reclaimed asphalt mixtures in asphalt concrete plants were estimated and the emissions from the detailed processes of the production process were evaluated based on TRACI(the tool for the reduction and assessment of chemical and other environmental impacts). METHODS : To estimate the energy consumption of the aggregate drying process, which consumes a significant amount of energy in the production process, an energy consumption calculation model based on the thermal equilibrium equation was used, and the energy consumed for material transportation, storage, and operation of other facilities was cited from the literature. RESULTS : For the system boundary conditions established and the inventory considered, the emissions to produce one ton of hot mix reclaimed asphalt mix are greater than the emissions to produce one ton of hot mix asphalt mix for a number of key impact categories. The process of producing hot mix reclaimed asphalt mixtures was evaluated to consume more resources and energy in the production of recycled aggregates and heating for drying than in the production of hot mix asphalt mixtures, but less resources and energy in the production of binders and natural virgin aggregates and the heating to heat these materials. CONCLUSIONS : The results of the emissions assessment using the life cycle inventory for the production of hot mix asphalt mixtures were generally similar to the results understood in the field and in much of the literatures, confirming the reliability of the methodology. However, in order to evaluate the dominance of specific processes or mixtures, it is believed that the construction of a wide range of inventory databases after inventory redesign is necessary for a specific and rigorous assessment.

This study selected two labor-intensive processes in harsh environments among domestic food production processes. It analyzed their improvement effectiveness using 3-dimensional (3D) simulation. The selected processes were the “frozen storage source transfer and dismantling process” (Case 1) and the “heavily loaded box transfer process” (Case 2). The layout, process sequence, man-hours, and output of each process were measured during a visit to a real food manufacturing factory. Based on the data measured, the 3D simulation model was visually analyzed to evaluate the operational processes. The number of workers, work rate, and throughput were also used as comparison and verification indicators before and after the improvement. The throughput of Case 1 and Case 2 increased by 44.8% and 69.7%, respectively, compared to the previous one, while the utilization rate showed high values despite the decrease, confirming that the actual selected process alone is a high-fatigue and high-risk process for workers. As a result of this study, it was determined that 3D simulation can provide a visual comparison to assess whether the actual process improvement has been accurately designed and implemented. Additionally, it was confirmed that preliminary verification of the process improvement is achievable.

The thermocatalytic decomposition of methane is a promising method for hydrogen production. To determine the cause of carbonaceous catalyst deactivation and to produce high-value carbon, methane decomposition behavior and deactivated catalysts were analyzed. The surface properties and crystallinity of a commercial activated carbon material, MSP20, used as a methane decomposition catalyst, varied with the reaction time at a reaction temperature of 900 °C. During the initial reaction, MSP20 provided a methane conversion of ≥ 50%; however, the catalyst exhibited rapid deactivation as crystalline carbon grew at surface defects; after 15 min of reaction, approximately 33% methane conversion was maintained. With increasing reaction time, the specific surface area of the catalyst decreased, whereas crystallinity increased. The R-square value of the conversion–crystallinity relationship was significantly higher than that of the conversion–specific surface area relationship; however, neither profile was linear. The activity of the activated carbon catalyst for methane decomposition is mainly determined by the complex actions of the specific surface area and defect sites. The activity was maintained after an initial sharp decline caused by the continuous growth of crystalline carbon product. This study presents the application of carbonaceous catalysts for the decomposition reaction of methane to form COx- free hydrogen, while simultaneously yielding porous carbon materials with an improved electrical conductivity.

This study presents the synthesis, characterization, and utilization of marine macroalgae-derived bio-carbon catalysts (BC and KOH-AC) for the efficient conversion of waste cooking oil (WCO) into biodiesel. The biochar (BC) was produced through slow pyrolysis of macroalgal biomass, which was subsequently activated with potassium hydroxide (KOH) to produce a KOH-modified activated carbon (KOH-AC) catalyst. Advanced characterization techniques, including SEM, EDX, XRD, FTIR, and TGA, were used to examine the physicochemical characteristics of the catalysts. The synthesized catalysts were utilized to produce biodiesel from WCO, and the results revealed that the highest biodiesel yields, 98.96%, and 47.54%, were obtained using KOH-AC and BC catalysts, respectively, under optimal reaction conditions of 66 °C temperature, 12.3 M/O molar ratio, 130 min time, and 3.08 wt.% catalyst loading via RSM optimization. The kinetic and thermodynamic parameters, such as k, Ea, ΔH, ΔS, and ΔG, were determined to be 0.0346 min− 1, 43.31 kJ mol− 1, 38.98 kJ mol− 1, − 158.38 J K− 1 mol− 1, and 92.58 kJ mol− 1, respectively. The KOH-AC catalyst was recycled up to five times, with a significant biodiesel yield of 80.37%. The fuel properties of the biodiesel met ASTM (D6751) specifications, ensuring that it has excellent fuel characteristics and can be used as an alternative fuel.

Recently, in the case of the root industry, although it is a basic industry that forms the basis of manufacturing competitiveness, there continues to be a shortage of manpower due to reasons such as dangerous working environments, industrial economic difficulties, and low wage systems. In addition, the demand for automation of production lines using robots is increasing due to a shrinking labor market due to a decrease in the working population due to aging, higher wages, shorter working hours, and limitations of foreign workers. In this study, a system was developed to automate the injection molding process for producing ball valves for automobiles by applying robot system. The applied process flow consists of alignment and insertion of insert parts, and removal, transfer, and loading of the product after injection molding, which is currently performed manually. Through the application of the developed robot automation system, the cycle time was improved by more than 30% and the defect rate was reduced by more than 70%.

The production process of ultra-pure water (UPW) involves dozens of unit processes such as reverse osmosis (RO), pretreatments, membrane degasifier, and several ion exchange processes. Recently, continuous electrodeionization (CEDI) has replaced the 2-bed and 3-tower (2B3T) ion exchange process. As a result, the majority of wastewater in UPW production now comes from the RO concentrate. The important of RO in UPW production is to produce high-quality water with a low ion concentration (around 1 mg/L) for CEDI feed water. Minimizing RO concentrate is essential to reduce the wastewater produced in the UPW production process. This can be achieved by maximizing the recovery of the RO system. However, increasing the recovery is limited by the water quality of the RO permeate. To ensure high-quality permeate water, the RO system is designed with a two-pass configuration. The recovery of each pass in the RO system is limited (e.g., < 85%) due to the expected increase in permeate water concentration at higher RO feed water concentrations. Interestingly, tests using 4-inch RO modules with low concentration feed water (≤ 35 mg/L as NaCl) revealed that the permeate concentration remains almost constant regardless of the feed water concentration. This implies that the recovery of the first RO pass can be increased as long as the average feed/concentrate concentration of the second RO pass is less than 35 mg/L. According to this design criterion for the RO system, the recovery of the first and second RO pass, with a feed water concentration of 250 mg/L as NaCl, can be increased up to 94.8% and 96.0%, respectively. Compared to the conventional RO system design (e.g., 70% and 80% for the first and second RO pass) for UPW production, this maximum recovery design reduces the volume of RO feed and concentrate by up to 38.4% and 89.2%, respectively.

Metal material production process machinery is becoming larger due to the development of industry. Since there are many overseas manufacturers of large machines used in industrial fields, there are limitations in investigating the manufacturer's noise prediction method and measurement method. A noise map was prepared to obtain information necessary for noise reduction and to effectively manage noise companies. It was modeled with the drawings provided to prepare the noise map and the results of the actual measurement of the site. In order to improve the noise environment of workers, there was a noise reduction effect when a soundproof wall was installed between the noise source and the worker's workplace.

The existing production and manufacturing process was manually operated and the cleaning process was not constant due to poor environmental conditions for several hours, so the production efficiency was significantly lowered and manufacturing cost was increased. In this R&D, productivity improved by doubling the production of 300 units per hour to 700 units, and in this development, manufacturing costs were lowered through this process improvement project based on automotive shoba automation technology.

난자의 성숙과정과 노화에 관한 이해는 인공수정과 체외수정 최적기를 판단하기 위하여 가장 중요한 연구내용으로 알려져 있다. 이러한 기작은 번식 호르몬들에 의하여 조절되는 것으로 알려져 있으나 난자 세포질 변화에 관한 내용은 잘 알려져 있지 않다. 본 연구에서는 산화질소물(nitric oxide, NO)이 난자 성숙과정에서 증가하는 것을 밝혔으며 난자의 미성숙단계(germinal vesicle stage, GV)와 난자핵막붕괴단계(germinal vesicle breakdown, GVBD) 및 성숙완료단계(metaphase II, MII)단계에서 생산되는 NO의 양을 비교하였다. 또한, 난자를 체외에서 배양할 때, MII단계로 성숙되지 않는 성장 단계의 난자에서는 NO의 증가 현상을 관찰할 수 없었고, 세포질이 불균일한 노화된 난자에서는 NO가 증가된 상태로 유지되는 특성이 있음을 밝혔다. 이러한 결과는 NO의 작용이 난자의 성숙과정과 난자 노화과정에서 중요한 기능을 담당하고 있음을 보여주고 있다.