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.

The spherical mesophases are the main precursors for the high tap density of carbonaceous anode batteries. However, it is challenging to control mesophase size without coalescence and no deformation since it quickly coalesces into a regular large sphere. Here, we propose a feasible extraction method to refine the spherical size of mesophase using benzene. Thermogravimetric and differential scanning calorimetry analysis of untreated pitch revealed that the maximum temperature for mesophase nucleation should not exceed 410 °C to provoke the nucleation of mesophase spheres while maintaining a high pyrolysis yield. The extraction results showed that the extraction weight tends to decrease with an increase in the solvent ratio. There is an exponential relationship between the influence of solvent ratio and the ability for extraction. The solubility of the spherical mesophase in benzene is size-dependent and can dissolve selectively spherical mesophases smaller than 5 μm. Consequently, a monodisperse spherical mesophase was obtained. The reason for forming uniform mesophase spheres can be explained by their thermodynamic state, as described by the “two-step” classical nucleation theory. Benzene effectively improves the size distribution of spherical mesophase by dissolving small sizes while retaining large ones.

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%.

This study aimed to assess and determine the optimal model for predicting the full bloom date of ‘Fuji’ apples across South Korea. We evaluated the performance of four distinct models: the Development Rate Model (DVR)1, DVR2, the Chill Days (CD) model, and a sequentially integrated approach that combined the Dynamic model (DM) and the Growing Degree Hours (GDH) model. The full bloom dates and air temperatures were collected over a three-year period from six orchards located in the major apple production regions of South Korea: Pocheon, Hwaseong, Geochang, Cheongsong, Gunwi, and Chungju. Among these models, the one that combined DM for calculating chilling accumulation and the GDH model for estimating heat accumulation in sequence demonstrated the most accurate predictive performance, in contrast to the CD model that exhibited the lowest predictive precision. Furthermore, the DVR1 model exhibited an underestimation error at orchard located in Hwaseong. It projected a faster progression of the full bloom dates than the actual observations. This area is characterized by minimal diurnal temperature ranges, where the daily minimum temperature is high and the daily maximum temperature is relatively low. Therefore, to achieve a comprehensive prediction of the blooming date of ‘Fuji’ apples across South Korea, it is recommended to integrate a DM model for calculating the necessary chilling accumulation to break dormancy with a GDH model for estimating the requisite heat accumulation for flowering after dormancy release. This results in a combined DM+GDH model recognized as the most effective approach. However, further data collection and evaluation from different regions are needed to further refine its accuracy and applicability.

This study was conducted to investigate the growth characteristics of cucumber (Cucumis sativus L. ‘Joeunbaekdadagi’) and tomato (Solanum lycopersicum L. ‘Dotaerang Dia’) seedlings by light intensities and CO2 concentrations in a closed-type plant production system (CPPS). Cucumber and tomato seeds were sown in 50-cell trays and germinated in CPPS at air temperature 25 ± 1°C and relative humidity 50 ± 10% for 4 days. After germination, the CO2 concentrations and light intensity treatment were treated at 500 (ambient), 1,000, and 1,500 μmol·mol-1 and 100, 200, and 300 μmol·m-2·s-1 photosynthetic photon flux density (PPFD), respectively. The leaf area of cucumber showed the highest value in CO2 1,500 μmol·mol-1. However, the leaf area of the tomato had no significant difference in CO2 concentrations and light intensities treatments. In cucumber and tomato both seedlings, the growth and quality such as compactness and leaf area rate were increased with the increase of light intensity, and there were highest in 300 μmol·m-2·s-1. The root surface and number of root tips of cucumber and tomato seedlings were significantly increased with the increase in light intensity. In conclusion, the regulation of the CO2 concentrations and light intensity can control the growth and quality of cucumber and tomato seedlings in CPPS, especially, increasing the light intensity can improve more significantly the growth and quality of seedlings.

PURPOSES : In this study, energy-consuming processes in asphalt plants were evaluated, and the drying and mixing processes were characterized using a thermal equilibrium equation-based model to quantitatively estimate the amount of energy consumed during the production of mixtures in asphalt concrete plants. METHODS : An energy consumption model based on the thermal equilibrium equation was used to estimate the energy consumption of the aggregate drying process that consumes the maximum energy; the energy consumed for material transportation, storage, and operation of other facilities was cited from the literature. The results were compared with the actual results obtained for recycled hot asphalt mixtures and recycled warm mix asphalt mixtures, and a sensitivity analysis was performed by varying the conditions. RESULTS : An analysis of the main processes required to produce asphalt mixtures showed that the water content had the largest impact on energy consumption (approximately 80%). This quantitatively supports the opinion of field practitioners that maximum energy is consumed during aggregate drying. Although some discrepancies were observed, the results were found to be reasonable and within the range of typical measurements. CONCLUSIONS : The thermal energy consumption estimation model provides consistent results that reflect the characteristics of the mixture and can be used to derive the thermal energy consumption rates for individual materials, such as aggregates and binders. This can be used to identify the priorities for process optimization within a plant.

Focusing on Hwaseokjeong in Paju, the work seeks to clarify the social production of Nujeong (樓亭: Korean traditional pavilions) space, which took place over the 1960s and 70s, and its cultural-political implications. To make the effort as such meaningful, a theoretical framework based not merely on the thesis of ‘social production of space’ advocated by Henri Lefebvre but especially on some discussions related to ‘state production of space’ is prepared, according to which Hwaseokjeong is analyzed and explained. As a consequence, two principal arguments are put forward: one is that Hwaseokjeong was a social space which had been built and constructed in accordance with the unique mode of production dominating Korean society at that time called ‘the state mode of production (le mode de production étatique )’; the other is that what lies beneath the denotation of a ‘social space of tradition restoration’ that Hwaseokjeong appears to carry is in fact the connotation of ‘infiltration of anti-communist ideology’. All of these claims are once again supported both by examining Roland Barthes's semiology and mythologies and by considering Hwaseokjeong's Pyeonaek (扁額: a plaque or framed text) as ‘the practice of naming power through J esa (題詞: inscribing dedications)’. While providing a succinct summary, the paper finally evaluates what ‘social production of space’ implies to social practices of architecture and related criticisms by taking into account the relationship between visibility and readability of space including buildings.

본 논문은 아시아에서 돈육 생산과 소비의 강국인 중국, 일본, 한국 3개국의 과거와 현재 돈육 산업을 조사하고 향후 돈육 생산과 소비를 예측하는 것을 목적으로 한다. 중국은 경제 시스템 변화와 가속화된 경제 성장으로 돈육의 생산과 소비에서 높은 순위를 차지할 수 있었고, 양돈 산업은 계속 발전할 것이며, 생산과 소비는 계속 증가할 것으로 예상된다. 일본의 돈육 생산량은 오랫동안 꾸준히 감소해 왔다. 일본은 돈육 수입량이 많아 순위가 높지만 수입량에 비해 소비가 크지 않아 수입량은 점차 줄어들 것으로 예상된다. 한국은 양돈산업의 발달과 대규모 농장 운영의 확대로 돈육 생산이 발달했고, 이를 통해 양돈 생산 분야에서 높은 순위를 차지하고 있다. 돈육의 소비도 지속적으로 증가하고 있다. 농업 부문의 경제적 측면에서는 돈육 생산과 소비의 비율이 계속 증가하고 있다. 중국, 일본, 한국의 돈육 생산과 소비는 농업부문뿐만 아니라 세계 경제에도 상당한 영향을 미칠 것이다.

유기농 논이용 콩-밀 생산체계에서 재배유형별 밀 파종 전 경운여부에 따라 경운/무경운 처리, 콩 재배시 비닐 피복 여부에 따라 피복/무피복 처리, 논의 생태적 개선 여부에 따라 개선/대조구 처리로 시험구를 조성하여 밀 재배 중 곤충자원의 출현 및 분포특성을 조사 비교하였다. 출현 곤충의 총 종수는 20종으로 경운 14종, 무경운 14종으로 차이는 없었고 피복 14종, 무피복 16종이었으며 개선구 18종, 대조구 13종으로 개선처리에서 곤충 출현 종수가 많았다. 출현 곤충의 총개체수는 경운 124개체, 무경운 76개체로 경운처리에서 많았고, 피복 100개체, 무피복 100개체로 차이가 없었으며 경운-무피복-개선에서 40개체로 가장 많았다. 유기농 밀에 피해를 주는 해충 으로 노린재류는 갈색날개노린재가 가장 많이 발생하였고, 메추리노린재, 시골가시허리노린재도 출현하였으 며 재배유형별 발생 개체수는 경운 81마리, 무경운 39마리로 경운에서 많았고, 무경운-피복-대조(7) = 무경운-무 피복-대조(7) < 무경운-무피복-개선(9) < 경운-피복-개선(12) < 경운-무피복-대조(13) < 무경운-피복-개선(16) < 경운-피복-대조(27) < 경운-무피복-개선(29) 순으로 발생하였다.

미국선녀벌레는 2009년 발견이후 현재 131개 시군에 15,730ha가 발생되고 있다. 주로 단감 등 10여종 이상의 작물을 흡즙하여 피해를 준다. 2017년 이탈리아 파도바 대학에서 천적인 선녀벌레집게벌(Neodryinus typhlocybae)을 도입하여 국립농업과학원에서 생태특성 조사, 대량사육 기술개발 및 미국선녀벌레 발생 현장에 방사하고 있다. 선녀벌레집게벌은 미국선녀벌레 어린약충(1~3령)에 기생하면 암컷의 비율이 낮고 수컷은 2화 성 개체가 많아져 생산이 비효율적이다. 본 연구에서 어린약충에 기생할 때 보다 노숙약충에 기생할 경우 3배정 도 암컷생산의 비율이 높아졌고, 월동하고 있는 고치들을 5월 중순 무렵에 20℃의 서늘한 곳에 보관하면 우화시 기를 상온에 놓아둔 것에 비해 10일 이상 늦추는 결과를 얻었다.