This paper explores the potential application of carbon nanotubes (CNTs) in the construction industry, as CNTs can effectively serve as nano-fillers, bridging the voids and holes in cement structures. However, the limited dispersibility of CNTs in water necessitates the use of dispersing agents for achieving uniform dispersion. In this study, two kinds of cement superplasticizers, polycarboxylate ether (PCE) and sulfonated naphthalene formaldehyde (SNF) were employed as dispersing agents to improve the interfacial affinity between CNTs and cement, and to enhance the strength of the cement nanocomposites. Contact angle experiments revealed that the utilization of PCE and SNF effectively addressed the interface issues between CNTs and cement. As a result, the cement nanocomposite with a CNT to PCE ratio of 1:2 exhibited an approximately 6.6% increase in compressive strength (73.05 MPa), while the CNT:SNF 1:2 cement composite showed a 4.7% increase (71.72 MPa) compared to plain cement (68.52 MPa). In addition, the rate of crack generation in cement nanocomposites with CNTs and dispersing agents was found to be slower than that of plain cement. The resulting cement nanocomposites, characterized by enhanced strength and durability, can be utilized as safer materials in the construction industry.
This study aimed to develop the in vitro method using domestic commercial diets to estimate nutrient digestibility in dogs. The existing in vitro method were tested and compared with literature data to develop new in vitro method. The development of in vitro method progressed as follows: modification of pepsin solution to an activated form and supplementation with 1% lipase. All the in vitro method progressed to 4 hours of stomach simulation and 2 hours of small intestine simulation. In vivo digestibility was measured using the same diets as beagle dogs. The supplementation of lipase methods showed significantly improved (p < 0.05) DM, OM, and EE than the existing and modified pepsin solution methods. The correlation between in vitro and in vivo data in DM, OM, and EE digestibility was high (r2 = 0.889, 0.907, and 0.721, respectively), and the correlation between in vitro and in vivo data in CP and GE digestibility was medium (r2 = 0.681 and 0.536, respectively). The current in vitro method is similar to in vivo digestibility and helps potentially predict digestibility for dogs. In conclusion, this developed in vitro method suggests that it can help estimate the nutrient digestibility of dogs' diets without in vivo experiments.
Valgus Kolbe, 1909 is a small genus of Cetoniinae, with 20 described species worldwide. In Korea, only one species, Valgus koreanus Sawada, have been recorded. Species of this genus have been known that they are commonly associated with termite colonies. They feed on the wall of termite burrows in logs or standing dead trees. In this study, we report a new species of this genus, Valgus gwangneungensis sp. nov.. We provide a key to the species of Valgus, description of the new species and photographs of habitus and male aedeagus.
M. pruinosa has been found on 98 families and 345 species of plants, indicating a wide host range. Since its first report in a persimmon orchard in Gimhae in 2009, it had spread to 126 municipalities over 12,429 ha. Because of powerful dispersal ability, it’s difficult to control with insecticides. Therefore, it is necessary to reduce the population density through the release of M. pruinosa’s natural enemy, N. typhlocybae. N. typhlocybae females prey on or externally parasitize the nymphs of M. pruinosa. This natural enemy was introduced from Italy in 2017 through an international cooperative project between National Institute of Agricultural Sciences and University of Padova for controlling the sporadic pest, Metcalfa pruinosa. This study reported the results of mass rearing N. typhlocybae indoors and releasing them outdoors from 2020 to 2023 in 21 regions nationwide, showing an average parasitism rate of 27.3% and an average production of 7.9 cocoons per host, suggesting the possibility of their establishment in Korea.
We investigated the effects of fluctuating temperature on development and fertility of M. persicae at different temperature conditions, 10, 15, 20, 25, 28, and 30±5℃, respectively. In this study, we collected detailed data on development periods, and fertility of M. persicae at six different temperatures. We analyzed the life table parameters of M. persicae using age-stage, two-sex life table program. The intrinsic and finite rate of increase were the highest at 25±5℃. The fertiltiy was the highest at 20±5℃.
This study focused on the genomic analysis of Anopheles kleini and Anopheles pullus, both vectors of vivax malaria within the Anopheles Hyrcanus group. Using Illumina NovaSeq600 and Oxford Nanopore platforms, we identified 126 and 116 contigs, along with 40,420 and 32,749 genes from An. kleini and An. pullus, respectively. The assembled genome sizes were 282 Mb for An. kleini and 247 Mb for An. pullus, which are within a similar range to the sizes previously estimated by digital PCR (249 Mb and 226 Mb). We are currently also estimating the genome sizes of other Anopheles spp. and manually curating key genes determining vectorial capacity.
Bacillus thuringiensis (Bt) is widely used as an environmentally friendly insecticide compared to chemical insecticides. However, challenges such as difficulty in direct practical application, limited efficacy duration, and stability have been identified. To solve these issues, formulation-based research is being extensively conducted. In this study, the high insecticidal activity strain Bt IMBL-B9, identified in previous research, was subjected to large-scale cultivation using a fermentor. Subsequently, various formulations were developed through formulation processes. and characteristics such as their wettability, suspensibility and particle size were assessed to select the optimized formulation.
Spodoptera exigua is one of the worldwide distributed agricultural pest insects and has been known to show high resistance to conventional chemical insecticides. Autographa california multiple nucleopolyhedrovirus (AcMNPV) has been used as eco-friendly biological control agent for S. exigua, as it exhibits high level of host specificity, stability and safety. In this study, for formulation of AcMNPV, the optimal conditions for mass-production of AcMNPV polyhedra was established using S. exigua larvae. Mass-produced AcMNPV polyhedra was formulated as wettable powder using microencapsulation method and its control efficacy against S. exigua was evaluated both in laboratory and semi-field experiment. Chinese cabbage treated with the AcMNPV formulation showed significantly reduced damage rates, suggesting that the AcMNPV formulation in this study could be useful for control of S. exigua
The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) will provide all-sky spectral survey data covering optical to mid-infrared wavelengths with a spatial resolution of 6.′′2, which can be widely used to study galaxy formation and evolution. We investigate the galaxy-galaxy blending in SPHEREx datasets using the mock galaxy catalogs generated from cosmological simulations and observational data. Only ∼0.7% of the galaxies will be blended with other galaxies in all-sky survey data with a limiting magnitude of 19 AB mag. However, the fraction of blended galaxies dramatically increases to ∼7–9% in the deep survey area around the ecliptic poles, where the depth reaches ∼22 AB mag. We examine the impact of the blending in the number count and luminosity function analyses using the SPHEREx data. We find that the number count can be overestimated by up to 10–20% in the deep regions due to the flux boosting, suggesting that the impact of galaxy-galaxy blending on the number count is moderate. However, galaxy-galaxy blending can marginally change the luminosity function by up to 50% over a wide range of redshifts. As we only employ the magnitude limit at Ks-band for the source detection, the blending fractions determined in this study should be regarded as lower limits.
산오이풀(Sanguisorba hakusanensis)은 한국의 자생식물 이며 정원소재로써 가치가 있지만, 생육 및 생리적 특성 및 정 원 적응 여부에 대하여 알려진 정보가 많지 않아 이용에 어려 움을 겪고 있다. 본 연구에서는 자생식물인 산오이풀의 관수 주기 및 NaCl 농도에 따른 생장, Fv/Fm, NPQ, 성분 변화, 무기성분 변화를 조사하여 내건 및 내염성 보유 여부, 생육 한 계 범위, 스트레스 환경에서 생육을 유지하기 위한 반응을 파 악하고자 했다. 실험 결과 NaCl 무처리구의 관수주기에 따른 성분 분석에서 엽록소 함량의 감소를 제외하고 유의한 차이가 나타나지 않았으나 이는 토양수분함량이 건조 스트레스를 유 발할 정도로 감소하지 않았기 때문으로 보인다. 염 처리에서 는 2주 이후 급격한 스트레스 반응이 나타났고 3주차부터 고 사하기 시작하여 6주차에 모든 개체가 최종 고사했다. 이러한 결과는 2주까지 염 스트레스에 의해 유발되는 2가지 스트레 스 중 초기에 나타나는 삼투 스트레스에는 저항하였으나 이후 나타나는 NPQ의 감소 등 이온 스트레스에 의해 유발된 광합 성 기구 붕괴로 인해 정상적인 생육을 유지할 수 없었기 때문 에 나타난 것으로 보인다. 그러나 무기이온 분석은 이온 스트 레스에 저항하기 위한 메커니즘의 존재 가능성을 시사하였다. 상대적으로 염 농도가 낮을 때에는 세포내 Ca2+ 및 K+ 수준이 높았는데, 이는 Ca2+ 수준이 높아짐에 따라 Na+를 세포 밖으 로 방출시키는 단백질, Na+를 K+와 함께 수송하는 단백질이 기능하여 Na+축적을 지연시키는 반응이 있었음을 시사한다. 그러나 NaCl을 고농도로 처리했을 때는 이러한 반응이 관찰 되지 않았다. 따라서 산오이풀은 염 스트레스에 의해 야기되 는 삼투 스트레스에 강한 저항성을 가지고 있고 이온 독성을 줄이기 위한 메커니즘으로 Na+ 세포내 축적을 지연시키는 것으로 보이지만, 심한 염 스트레스를 받았을 때 나타나는 급격 한 반응에서 이러한 메커니즘이 기능하지 못하고 이온독성에 매우 취약한 것으로 여겨진다. 본 연구를 통해 자생식물인 산 오이풀의 활용을 늘리는 데 기초적인 자료를 제공할 수 있을 것으로 생각된다.
Most of the radioactive wastes generated during the nuclear fuel processing activities conducted by KEPCO Nuclear Fuel Co., Ltd. are classified as the categories of intermediate and low-level radioactive waste. These radioactive waste materials are intended for permanent disposal at a designated disposal site, adhering strictly to the waste acceptance criteria. To facilitate the safe transportation of radioactive waste to the disposal site, it is necessary to ensure that the waste drums maintain a level of criticality that complies with the waste acceptance criteria. This necessitates the maintenance of subcritical conditions, under immersion or optimal neutron moderation conditions. This paper presents a criticality safety assessment of concrete radioactive waste under the most conservative conditions of immersion and moderation conditions for waste drums. Specifically, In order to send radioactive waste, which is the subject of criticality analysis, to a disposal facility, pre-processing operations must be performed to ensure compliance with waste accepatance criteria. To meet the physical characteristics required by the accepance criteria, particles below 0.2 mm should not be included. Thus, a 0.3 mm sieve is used to separate particles lager than 0.3 mm, and only those particles are placed in drums. The drums should be filled to achieve a filling ratio of at least 85%. A criticality analysis was conducted using the KENO-VI of SCALE. The Criticality Safety Analysis Results of varying the filling ratio of concrete drums from 85% to 100% presented in an effective multiplication factor of 0.22484. Additionally, the effective multiplication factor presented to be 0.25384 under the optimal moderation conditions. This demonstrates full compliance with the USL and criticality technology standards set as 0.95.
The bentonite buffer material is a crucial component for disposing of high-level radioactive waste (HLW). Several additives have been proposed to enhance the performance of bentonite buffer materials. In this study, unconfined compression tests were conducted on bentonite mixtures as well as pure bentonite buffer material. Joomunjin and silica sands were added at a 30% ratio, and graphite was added at 3% along with bentonite. The unconfined compression strength (UCS) and elastic modulus of pure bentonite were found to be 20% to 50% higher than those of bentonite mixtures under similar dry density and water content conditions. This decrease in strength can be attributed to the reduced cross-sectional area available for bearing the applied load in the bentonitemixture. Furthermore, the 3% graphite-bentonite mixture exhibited a 10% to 30% higher UCS and elastic modulus compared to the 30% sand-bentonite mixtures. However, since the strength properties of additive-bentonite mixtures are lower than those of pure bentonite, it is essential to evaluate thermohydraulic-mechanical functional criteria when considering the use of bentonite mixtures as buffer materials.