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.

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.

2022년 10월부터 2023년 5월까지 친환경 딸기재배 농가에서 점박이응애는 칠레이리애응애와 사막이리응애, 진딧물은 콜레마니진디벌을 대상으로 하는 천적처리구와 유기농자재를 사용하는 관행방제구에서 천적의 해 충 밀도억제 효과를 조사하였다. 천적처리구에서 점박이응애 성충 밀도는 잎당 1.5마리 이하, 알은 4개 이하로 관리되었고, 사막이리응애는 잎당 최대 0.4마리까지 증가하여 점박이응애 밀도억제에 많은 영향을 미친것으로 보인다. 반면, 관행방제구에서 점박이응애 밀도는 천적 방사구에 비하여 오히려 많은 발생량을 보였지만, 3월 9일부터는 사막이리응애의 증가와 유기농자재의 효과로 점박이응애 밀도는 급격하게 감소하였다. 진딧물 천적 처리구에서 진딧물 밀도는 1월부터 발생하였으며 3월 상순에 잎당 0.3마리까지 증가하였으나 이후 감소하였고, 콜레마니진디벌은 진딧물 발생이 많지 않아 3.9마리/㎡(2회) 방사하는 데 그쳤다. 한편, 관행방제구 포장의 진딧 물은 유기농자재의 영향으로 거의 발생하지 않았다.

In this study, the MoS2 nanoparticles grown on crumpled 3D graphene microball (3D GM–MoS2) was synthesized using a microfluidic droplet generator with thermal evaporation-driven capillary compression and hydrothermal reaction. The morphology and size of 3D GM–MoS2 are controlled by the concentration of nano-sized graphene oxide (GO) and the flow rate of oil phase on the droplet generator. The 3D GM–MoS2 with fully sphere-shape and uniform size (~ 5 μm), and homogeneous growth of MoS2 nanoparticles could be synthesized at the flow rate of the oil phase of 60 μL/min with the optimized GO concentration of 1.0 mg/mL, and ( NH4)2MoS4 concentration of 2.0 mg/mL.

본 연구는 지속가능한 유기농업의 실천을 위하여 국내 작부체계와 농업환경에 적합한 한국형 현장적용 기법을 구축하고자 수행하였다. 본 연구의 기본 개념은‘Natural Enemy in First (NE가 먼저)’로 해충 발생시기의 예찰 없이 주 작물을 정식함과 동시에 천적과 선발한 보조식물을 혼합 적용해서 해충발생 이전에 천적을 포장에 먼저 정착시키는 생물적 방제기법이다. 미끌애꽃노린재 서식처로 Portulaca sp.를, 콜레마니진디벌 서식처로 옥수수를 선발하여 시설 토마토에서 방제효과를 확인하였다. 미끌애꽃노린재 단독처리와 천적 서식처(Portulaca sp.) 혼합처리구에서 관행방제 처리구(약제처리)대비, 각각 82%, 73%의 총채벌레 밀도 억제 효과를 확인할 수 있었다. 진딧물의 경우, 모든 처리구에서 3줄기 당 평균 0.5마리 이하의 낮은 밀도를 유지하였다.

It was available to store both nymphs and adults of Geocoris pallidipennis at 5℃ for 3 weeks without negative effects on their survival, fecundity, and Bamisia tabaci nymph predation. Up to 140 days, it was also possible to store Micromus angulatus adults at low temperature, showing approximately 50% cumulative survival rate, but over 2 week cold storage was not suitable for their fecundity. With the increase of cold storage duration, the aphid predation by M. angulatus decreased, but it could be possible to cold store until 5 weeks without a significant effect on their aphid predation. Thus, short term cold storage of G. pallidipennis and M. angulatus could be useful for inundative biological control.

Three ambrosia beetle species, Xyleborus glabratus, Monarthrum mali, and Euwallacea fornicatus belong to subfamily, Scolytinae, showing similar morphology and body size, but their flight capability and patterns showed species-specific. Body length of Xyleborus glabratus and Monarthrum mali was negatively correlated with flight capabilities; shorter beetles performed longer average flights, longer single flights, total flight distance, and total flight time. Elytral length also was negatively correlated with flight distance in X. glabratus and M. mali. Conversely, only average flight time of E. fornicatus was positively correlated with body length, pronotal width, and elytral length. Body length had no effect on the flight velocity of any of the three beetle species examined. Therefore, our results indicate that body size characteristics of ambrosia beetles differentially influence on their dispersal by species.