Magnetic nanoparticles in nanofluid have a unique ability in that they can be influenced by an external magnetic field, making them a promising heat-exchanging fluid to meet the demands of highly efficient thermal systems. The parametric impact of the magnetic field (static and time-varying) on the heat exchanging rate of Fe3O4 nanoparticles and water-based ferrofluid was investigated in this study. The experimental setup for generating a variable frequency magnetic field and analyzing the thermal behavior of ferrofluid is presented. Temperature data was obtained as heat is transferred from heated water to the ferrofluid used as a coolant. An enhancement of the heat transfer of the magnetic nanofluid was observed when varying the magnetic field frequency, through experimental analysis. The concentration of Fe3O4 nanoparticles in the ferrofluid was varied (0.5 wt%, 1 wt%)to study the impact of nanoparticle loading on heat transfer. An alternative approach for controlling the heat exchange rate in thermal systems is proposed, utilizing the magnetic tunability of the ferrofluid.

Background: Heat stress during summer impairs reproductive performance in sows, causing summer infertility. Cytochrome P450 1A2 (CYP1A2) plays a crucial role in steroid hormone metabolism in the liver and has been shown to be upregulated under stress conditions. However, the effect of seasonal heat stress on CYP1A2 expression in sow ovaries remains poorly understood. Methods: Ovaries were collected from crossbred sows during different seasons in Korea. The control group (CON) was exposed to optimal temperatures for swine rearing (22.0-24.5℃) during spring, while the heat-stressed group (HS) experienced high temperatures (30.5-37.0℃) during summer. Temperature-humidity index (THI) was calculated to assess thermal stress severity. CYP1A2 expression was analyzed using Western blotting and immunohistochemistry (IHC), and these values were statistically compared with THI by Pearson’s correlation analysis. Results: The HS exhibited significantly higher THI values compared to the CON (88.11 vs. 66.67). Western blot analysis revealed significant upregulation of CYP1A2 expression in the HS compared to CON (1.89 vs. 1.00). IHC demonstrated that CYP1A2 was specifically localized in granulosa cells of mature follicles, with a significantly higher proportion of CYP1A2-positive follicles in the HS (15.92%) compared to CON (9.08%). When the obtained values were compared with THI values, CYP1A2 expression showed a strong positive correlation with THI (r = 0.41 and 0.74). Conclusions: This study revealed that heat stress can alter the ovarian microenvironment, including the expression of CYP1A2. These findings emphasize the need for effective thermal management strategies to mitigate heat stress-induced reproductive dysfunction in livestock production.

고속 스핀 에코를 이용한 T2 강조 영상에서 재자화 펄스의 FA 크기 변화에 따라 발생하는 전자파 유도 열을 정량적 으로 측정하고, 상변화 물질의 열 저장 특성을 활용하여 열 발생을 효과적으로 감소시킬 수 있는 방안을 모색하고자 하였다.실험에서는 상변화 물질을 적용한 조건과 적용하지 않은 조건에서 각각 FA의 증가에 따른 온도 변화를 평가 하였으며, 그 결과는 다음과 같다. 고속 스핀 에코 기반 T2 강조 영상에서 FA 크기의 증가에 따라 계산된 SAR 값은 상변화 물질 적용 여부와 관계없이 각각 0.64±0.048, 0.87±0.042, 1.33±0.042, 1.88±0.031 W/kg로 유사한 경향을 보였다.온도 변화 분석 결과, 상변화 물질을 적용하지 않은 조건에서 돼지 비계의 초기 스캔 온도는 19.3°C였으며, FA 증가에 따라 최대 21.9°C까지 상승하여 총 2.6°C의 온도 증가가 관찰되었다. 반면, 상변화 물질 을 적용한 조건에서는 동일한 초기 온도 19.3°C에서 19.7°C까지 상승하는 데 그쳐 0.4°C의 온도 증가만 나타났으며, 두 조건 간 약 2.2°C의 온도 차이를 보였다. 한편, 돼지 비계에 온열 경피 패치를 부착한 조건에서도 유사한 경향이 나타났다. 상변화 물질을 적용하지 않은 경우, 스캔 시작 온도 20.6°C에서 23.1°C로 총 2.5°C 상승하였으나, 상변화 물질을 적용한 경우에는 20.1°C에서 20.5°C로 0.4°C 상승하는 데 그쳐 약 2.1°C의 차이를 나타냈다. 이와 같은 결과 는 상변화 물질이 반복되는 고주파 자극에 의해 유도되는 온도 상승을 효과적으로 억제할 수 있음을 확인하였다. 전자파 흡수율 및 열 발생 저감에 대한 과학적 근거를 제공함으로써, 향후 MRI 검사 환경의 안전성 향상에 기초자료 로 활용되기를 기대한다.

본 연구에서는 인쇄 회로 열교환기 채널에서의 응력 집중 해석을 수행하였다. 응력 집중이 발생하는 응력 집중부의 응력을 도출하 기 위해 전체 시스템의 해석 결과를 활용하는 부모델링 기법을 사용하였다. 미세한 기하학적 형상과 비가역적 소성 변형을 고려한 부 모델의 탄성 및 소성 해석을 수행하였다. 탄성 및 소성 해석에서 얻은 응력을 통해 미세한 기하학적 형상이 PCHE의 응력 분포에 미치 는 영향을 파악하였다. 탄성 해석과 소성 해석에서의 최대 폰 미제스 응력을 비교하여 응력 집중부의 응력 집중 경향과 소성 변형을 확인하였다.

The role of the gut microbiota in colorectal cancer (CRC) development has garnered attention, highlighting probiotics as potential adjuncts in CRC prevention and treatment. In recent years, probiotics and their derivatives have demonstrated mechanisms that may contribute to anticancer properties. This study investigates the cytotoxic effects of Bifidobacterium bifidum KCTC 3357, Lacticaseibacillus rhamnosus KCTC 5033, Limosilactobacillus reuteri VA 103, Bacillus galactosidilyticus VA 107, and Lactococcus taiwanensis VE101 on CT-26 mouse colon carcinoma cells using live cells, heat-killed cells (paraprobiotics), and cell-free supernatants (CFS, postbiotics) through an MTT assay. The results indicate that live bacterial strains, such as KCTC 3357, VA 103, and VA 107, promoted CT-26 cell viability, while heat-killed cells and CFS exhibited dose-dependent cytotoxicity. Inactivated forms of KCTC 3357 and VE 101, as well as CFS at 10 mg/mL concentration of KCTC 5033, VA 103, and VE 101, showed the strongest antiproliferative effects. These findings suggest that non-viable probiotic derivatives, such as paraprobiotics and postbiotics, offer promising therapeutic potential for CRC, providing a safer and more stable alternative to live probiotics. However, further research is required to explore their mechanisms of action, in vivo efficacy, and potential clinical applications.

This study was conducted to investigate the effects of pretreatments and soybean oil on the physicochemical properties of mung bean starch and the textural properties of gels. Dry heat and microwave heat treatments were used as pretreatments to enhance the textural and storage qualities of mung bean starch gels. Pretreatment and the addition of soybean oil increased the swelling power and solubility of starch; particularly, dry heat treatment significantly increased the solubility of starch. In the RVA test, microwave heat treatment increased pasting viscosity, whereas dry heat treatment reduced pasting viscosity over all temperature ranges. Both pretreatments increased the peak time and gelatinization temperature. Dry heat treatment significantly increased the hardness, gumminess, and chewiness of mung bean starch gels compared to microwave heat treatment, however, reduced cohesiveness and adhesiveness. The addition of soybean oil slightly increased the fracture strain. No significant difference was observed in the water-holding capacity due to pretreatment and oil addition. These results confirmed that the textural characteristics of the mung bean starch gel were affected by pre-heat treatment of the starches.

본 연구는 시멘트 산업의 대체연료(폐합성수지 등) 사용량 증대에 따라 이를 활용한 탄소배출 저감 및 시멘트/콘크리트 제조 적용 기술 및 방안에 대해 검토하고자 했으며, 향후 시멘트 산업의 탄소중립 실현을 위한 기초 자료로써 활용하고자 한다. 시멘트 제조 에 있어 폐합성수지 사용은 경제적 장점과 높은 발열량으로 인해 연료로서의 가치가 높은 것으로 나타났으며, 열경화성 수지는 부가가 치가 높은 저탄소 시멘트 복합체의 비반응성 골재로 작용할 수 있는 것으로 확인되었으며, 감마선 조사는 다양한 폐플라스틱의 성능 평가에 적용되는 것으로 확인되었다.

This paper presents a finite-difference method (FDM)-based heat-transfer model for predicting black-ice formation on asphalt pavements and establishes decision criteria using only meteorological data. Black ice is a major cause of winter road accidents and forms under specific surface temperature and moisture conditions; however, its accurate prediction remains challenging owing to dynamic environmental interactions. The FDM incorporates thermodynamic properties, initial pavement-temperature profiles, and surface heat-transfer mechanisms, i.e., radiation, convection, and conduction. Sensitivity analysis shows the necessity of a 28-d stabilization period for reliable winter predictions. Black-ice prediction logic evaluates the surface conditions, relative humidity, wind speed, and latent-heat accumulation to assess phase changes. Field data from Nonsancheon Bridge were used for validation, where a maximum prediction accuracy of 64% is indicated in specific cases despite the overestimation of surface temperatures compared with sensor measurements. These findings highlight the challenges posed by wet surface conditions and prolonged latent-heat retention, which extend the predicted freezing duration. This study provides a theoretically grounded methodology for predicting black ice on various road structures without necessitating additional measurements. Future studies shall focus on enhancing the model by integrating vehicle-induced heat effects, solar radiation, and improved weather-prediction data while comparing the FDM with machine-learning approaches for performance optimization. The results of this study offer a foundation for developing efficient road-safety measures during winter.

본 논문에서는 국내외 신재생에너지 정책 동향을 분석하고 히트펌프의 종류에 따른 농업적 적용 연구 분석을 통해 적용 성을 평가하고자 하였다. 국내에서는 설치비용이 상대적으로 많이 소요되고 보급율이 낮지만, 탄소중립을 위한 열 부문 온실가스 감축의 대안으로 주목할 필요가 있다. 히트펌프는 신 재생에너지원의 이용효율을 극대화하고 친환경적인 난방 및 냉방 솔루션을 제공함에 있어서 중요한 역할을 한다. 외국에 서는 신재생 열에너지 공급 의무화 제도로 건축물 내 열에너 지 사용량의 일정비율을 신재생에너지를 통해 공급하도록 의 무화하고 있으며, 신재생 열에너지 차액 지원 제도를 통해 신 재생에너지 이용 설비와 화석연료 이용 설비 간의 비용 차이 를 보상하고 있다. 우리나라 원예시설의 온실 난방도 예전에 는 80%가 유류였지만, 최근에는 고유가로 인하여 유류가 60%, 전기가 30%를 차지하고 있는 것으로 나타나고 있다. 따 라서, 전기로의 전환을 보여주고 있으며, 추후 농사용 전기 요 금 정책 변화 및 요금 인상 등에 대응 하기 위한 히트펌프 활용, 보급의 확대가 필요할 것으로 생각된다. 특히, 우리나라는 에 너지 가격적인 측면만을 볼 때는 히트펌프 보급에 매우 유리 한 여건에 있는 것이 사실이다. 외국과 비교하여 도시가스와 전력요금이 GDP대비 낮은 수준이며, 전력요금 대비 가스요 금은 상대적으로 비싼 수준이어서 히트펌프 보급에 의한 경제 성이 있다(Kim, 2016). 최근 전기요금이 인상되었지만, 농사 용 전기요금(저압)은 kWh당 59.5원으로 OECD 평균 전기요 금에 비교하여 저렴한 편이기 때문에 히트펌프 적용에 따른 효과는 크다고 할 수 있다. 우리나라는 겨울철 외기온도가 낮게 형성되는 기후적 특성 으로 인하여 난방 효율이 저하 문제로 AHP는 난방기로서의 관심이 크지 않은 실정이지만, AHP 보급은 화석연료, 가스 등 연료 사용 보일러 교체에 따른 온실가스 저감 효과를 나타낼 수 있다. 우리나라도 EU 등의 사례에서 알 수 있듯이 공기열 을 재생에너지로 인정함으로써 탄소중립실현을 위한 수단으 로 이용할 수 있을 것으로 기대된다. GHP 경우에는 지하에 파 이프 시스템이 매설되기 때문에 부지 소유 조건에 따라 시공 가능 여부가 결정될 수도 있으며, GHP의 적용 방식에 따라 굴 착 비용이 많이 소요될 수 있다. 지하수, 하천수, 해수, 폐수 등 에 포함된 열원으로부터 흡수하여 난방 및 냉방을 제공하는 시스템으로 축열시스템과 심야전기 활용 시에는 운전비를 크 게 절감할 수 있는 것으로 알려져 있다. 그러나, 슬러지(이물 질)가 유입·퇴적되면 효율이 저하되거나 고장을 일으킬 가능 성이 있기 때문에 유지관리에 대한 노력이 더 요구된다. 히트펌프를 적용하는데 있어서 다양한 요소들을 고려해야 한다. 히트펌프를 적용하려고 하는 지리적 조건에 따라 적합 한 히트펌프를 선정하는 것과 히트펌프를 적용하고자 하는 원 예시설의 크기에 적합한 용량을 선정하는 것이 효율적인 에너 지 이용을 위해 주요하다. 또한, 주 열원과 보조 열원을 결합한 시스템인 하이브리드 히트펌프를 이용하여 두 가지 열원을 최 적화하여 사용함으로써 에너지 효율성을 극대화하기 위한 노력도 필요하다. 히트펌프의 이용 확대를 위해서는 정부의 보 조금이나 세제 혜택을 통해 초기 비용 부담을 완화하는 것은 중요하지만, 그와 동시에 히트펌프의 에너지 효율을 향상 시 킬 수 있는 연구개발에도 투자가 필요할 것으로 사료된다. 이 로부터 히트펌프에 대한 기술 발전을 촉진하고, 보다 경제적 이고 지속 가능한 에너지 솔루션을 제공할 수 있기 때문이다.

This study was conducted to investigate changes in immunoglobulin G (IgG) concentration, nutrient content, and microbial communities of fresh and heat-treated Holstein colostrum collected from a colostrum bank operated by a local agricultural technology center in Gyeongsangbuk-do, South Korea. Of the 16 colostrum samples, 8 were heated at 60℃ for 30 min under a pressure of 0.9–1 bar. The colostrum samples were stored at −70℃ until use, at which time they were thawed at 50–55℃ in a water bath to analyze IgG levels, chemical composition, and microbiome, which was identified by 16S rRNA gene sequencing using the Illumina MiSeq-PE250 platform. The IgG concentrations were similar in fresh and heat-treated colostrum. The fat, protein, and lactose contents also did not differ in these samples. However, somatic cell count (SCC) was lower in heat-treated colostrum than those in fresh colostrum (p<0.05). At the phylum level for the microbiome of fresh colostrum, Proteobacteria (44.16%) was the most abundant taxa, followed by Bacteroidota (33.26%), Firmicutes (10.04%), Actinobacteriota (7.14%), and a marginal difference in the order of abundance was observed in heat-treated colostrum. At the genus level, bacteria belonging to Sphingomonas, Delftia, Ochrobactrum, Simplicispira, and Lactobacillus were more abundant (p<0.05) in the heat-treated colostrum, while the abundance of Acinetobacter in the fresh colostrum was four times more (p<0.05) than that in the heat-treated colostrum. Our results demonstrated that heating does not affect IgG level and colostrum composition but reduces SCC (p<0.05), suggesting that heat-treated colostrum can potentially be put to further use (e.g., feeding Hanwoo calves) without compromising its quality. Differences in the microbiome between the fresh and heat-treated colostrum were limited. Further studies are required to extensively investigate the quality and safety of colostrum collected from dairy farms to ensure better utilization and processing at a local agricultural technology center.

Background: South Korea has recently faced record-high temperatures, which have adversely affected dairy production. Holstein cows, the primary dairy breed globally, are particularly sensitive to heat stress. In contrast, Jersey cows have shown greater heat tolerance, as demonstrated by phenotypic studies. Methods: We investigated physiological and molecular responses to heat stress in Holstein and Jersey cows by measuring rectal temperature, milk yield, and average daily gain, confirming Holstein cows’ greater vulnerability. To explore molecular mechanisms, we analyzed circulating microRNA profiles from whole blood samples collected under heat stress and normal conditions using microRNA-sequencing. Differential expression patterns were compared between the two breeds to identify biological pathways associated with heat stress. Results: Four microRNAs (bta-miR-20b, bta-miR-1246, bta-miR-2284x, and bta-miR- 2284y) were significantly differentially expressed in both breeds under heat stress (|FC| ≥ 2, p < 0.05). Notably, bta-miR-20b and bta-miR-1246 were linked to corpus luteum function and progesterone biosynthesis, while bta-miR-2284x and bta-miR- 2284y were associated with immune responses. A comparison of 11 potential heat stress-related microRNAs identified in previous studies of Holstein cows revealed consistent expression trends in Jersey cows, albeit with lower fold changes, suggesting their superior heat resilience. Conclusions: Our study highlights the physiological and microRNA-based differences in heat stress responses between Holstein and Jersey cows. Jersey cows exhibited greater resilience, supported by more stable microRNA expression profiles and improved heat stress indicators, making them a promising breed for dairy production in increasingly hot climates.

Fetal Bovine Serum (FBS) plays a crucial role in animal cell culture; however, the increasing number of bovine fetuses used and sacrificed solely for FBS collection has raised ethical concerns globally. The welfare of fetuses during FBS blood collection has become a key focus of debate among animal welfare and ethics organizations worldwide. Previous studies indicate that heat-inactivated coelomic fluid (HI-CF) from the earthworm Perionyx excavatus may serve as a viable FBS alternative in adherent cell cultures. This study evaluates the potential of HI-CF as an FBS substitute during the in vitro maturation (IVM) stage of bovine embryo culture, with a focus on improving developmental rate through antioxidation effects. In this study, 2% HI-CF was incorporated into IVM media, assessing its impact on cell growth, differentiation, and the expression of genes related to antioxidation. The group of 2% of HI-CF exhibited a trend toward increased cleavage and blastocyst development rates compared to the control group. Although antioxidant genes such as NRF2 and GSR showed no statistically significant differences between the control and treatment groups, a trend toward increased expression was observed. Conversely, GPX1 displayed a trend of decreased expression. Notably, IGF1 and NQO1 were significant upregulated (p < 0.05) in the 2% HI-CF group. Additionally, oocytes stained with H2DCFDA showed a significantly reduced ROS levels (p < 0.05) in the 2% HI-CF group compared with controls. These findings suggest that HI-CF's antioxidative effects support enhanced cell growth and blastocyst development rate, surpassing those observed with FBS. Consequently, HI-CF shows promise as an effective alternative to FBS in vitro maturation of bovine oocytes.

This study was conducted using mold heat. By developing the cleaning process technology, the production test was improved by twice, and the heat washing time reduction test and defect rate were also reduced. We designed an automatic production system for automatic heat torches and devised an automated continuous process system to improve the mold process. The production capacity test doubled the production rate of the product per 1 hour from the target of 500 to 1,040 per hour, and the heat cleaning time reduction test measured the time from the beginning of heat injection to the product sample during the production process and the end time, which shortened the development target of 5 seconds (sec) to 2.78 seconds (sec), and the defect rate was reduced to 4.25% as a result of the defect rate test. The system development of this project has doubled the production volume

Microreactors, a type of Small Modular Reactor (SMR) under 20 MWt, are being developed globally for use in remote areas, utilizing fourth-generation nuclear technology for enhanced safety. However, there are no established standards for their commercialization. This study reviews road transport regulations for microreactors and proposes necessary design loads and evaluation criteria for their transport. Transport concepts were identified through a review of overseas developments, with requirements derived for both accident and normal conditions. The study also presents an approach for evaluating transport stability based on land-based nuclear plant regulations, considering load conditions from drops and puncture impacts, as well as random vibrations during road transport. This work aims to support the design of mobile reactor transport systems and contribute to new regulatory and licensing procedures for advanced reactors.

The heat transfer characteristics of double-pipe spiral heat exchanger using aluminum oxide nano-fluid were investigated by three different sizes of curvature size, experimentally. Five concentration of nano-fluid as working fluid were made and tested to analyze the heat transfer characteristics. As results, the heat transfer performance was improved at 0.25% of nano-fluid due to high thermal conductivity, however, as the concentration of nanofluid increased (~2.0%), the heat transfer performance deteriorated due to the increase in thermal resistance caused by the sedimentation of particles in the flow path. In addition, the nano-fluid has a higher pressure drop than water due to its high density and viscosity. The optimal range for heat transfer enhancement of nano-fluid was found to be less than 4.0 LPM in flow rate and 0.25% of nano-fluid concentration in this study.

초음속 혹은 극초음속 미사일의 레이돔은 공력 가열로 인해 과도한 열유속에 노출된다. 또한 미사일은 발사 후 속도와 고도가 변화 하면서 이에 따라 레이돔에 가해지는 열유속이 변화한다. 이러한 열부하에 의해 레이돔의 온도가 소재의 허용 온도를 초과하면, 레이 돔은 레이더를 보호하는 기능을 상실하게 된다. 따라서 비행 시나리오에 따른 레이돔의 열전달 특성을 고려하여 레이돔을 설계해야 한다. 본 연구에서는 준-비정상 기법을 적용하여 가상의 비행 시나리오에서의 레이돔의 열전달 특성을 분석하고 준-비정상 기법의 정 확도와 효율성을 평가하였다. 준-비정상 기법을 적용하여 시간에 따른 레이돔 외벽의 열유속과 온도 분포를 도출하였으며, 15초 이후 레이돔 외벽의 온도가 소재의 허용 온도 이상으로 가열되는 부분이 있는 것을 확인하였다. 또한 준-비정상 기법을 통해 도출된 결과 와 비정상 해석 결과를 비교하여 레이돔 평균 온도 측면에서 15% 이내의 오차로 예측할 수 있고 해석 소요 시간은 75%가 단축되는 것 을 확인하여 준-비정상 기법의 효율성을 입증하였다.

In this study, copper oxide, manganese oxide and zeolite, clays containing catalysts were prepared to remove hydrogen sulfide emitted in odor of industry. In order to change the heat treatment temperature, a catalyst was prepared 100 degrees from 600 degrees to 1,000 degrees. GC-MS was used to confirm the hydrogen sulfide removal performance. Although the removal performance produced at 600 degrees was maintained by and large, the removal performance decreased as the temperature increased. In particular, the catalyst manufactured at 900 and 1000 degrees had low removal performance. To find out the cause of the decrease in removal performance, the analytical devices XRD, BET, XRF were used. In order to confirm the properties of the catalyst before and after adsorption, SEM-EDS and CS were used. As a result of analyzing the Cu-Mn catalyst, it was confirmed that the material was adsorbed on the surface. To confirm the adsorbent material, SEM-Mapping was employed. And it was verified that the sulfur was adsorbed. Measuring the SEM-EDS 3Point, it was confirmed to be about 25.09%. Another test method CS analyzer (Carbon/Sulfur Detector) was also deployed. As a result of the test, sulfur was confirmed to be about 27.2%. So comparing the two sets of data, it was verified that sulfur was adsorbed on the surface.

Intense pulsed light (IPL), also known as high-intensity pulse light (HIPL), is an emerging non-thermal technology that uses light pulses of short duration, ranging from ultraviolet to infrared wavelengths, for microbial inactivation. This study aimed to investigate the sterilization of Saccharomyces cerevisiae in apple juice using IPL and mild heat. As the light intensity and treatment temperature increased, S. cerevisiae showed higher inactivation levels. When treated at 600 V and 50 °C for 10 min, clear and cloudy juices showed reductions of 3.95 log and 3.58 log, respectively. In terms of quality changes in apple juice due to pulsed light treatment, Brix and pH showed no change or a slight increase as light intensity, treatment temperature, and treatment time increased. Titratable acidity showed almost no change or a slight decrease. Color values showed a tendency for L and b values to decrease and a value to increase as light intensity, treatment temperature, and treatment time increased. Pulsed-light technology appears to be effective in sterilizing both clear and cloudy juices when combined with appropriate temperatures.