Over the last decade, there has been growing interest in the plastic degradation capabilities of insect because herbivorous insects may be a valuable resource for microorganisms that can break down synthetic plastics. Insects that can digest plastics using their gut microbiota are gaining interest for use in bioremediation, although their environmental benefits remain unknown. However, most plastics biodegraded by insect gut microbes are polyethylene, polystyrene with little knowledge available on the gut microbiome of insects capable of degrading other synthetic plastics. Therefore, there is an urgent need to secure microbial resources based on insect-microbiome interactions and promote end-of-life solutions for synthetic plastics.

Plastics are widely used in industries in human society and because of their structural stability, degradation is a serious global issue. To estimate the degradation of plastic, 31 edible mushrooms were cultured with the selected plastic films (polyethylene [PE], polystyrene [PS], and poly(ethylene terephthalate) [PET]) for 3 months at 25 °C. Measuring the weight of the films showed that four species of mushrooms, namely Porostereum spadiceum, Ganoderma lucidum, Coprinellus micaceus, and Pleurotus ostreatus, exhibited the highest degrees of plastic degradation. In addition, the mushrooms and fungi that exhibited the most significant plastic degradation were cross-cultured to promote this degradation. As a result, cross-cultivation of G. lucidum and Aspergillus niger showed a weight loss of 2.49% for the PET film. For the PS film, Aspergillus nidulans showed a weight loss of 4.06%. Cross-cultivation of A. nidulans and C. micaceus, which showed a weight loss of 2.95%, was noted as an alternative for PS biodegradation, but is harmful to humans. These bio-degradation effects of edible mushroom will contribute to the development of alternatives for eco-friendly plastic degradation.

The purpose of this study is to review the available literature on the effectiveness of fibers in preventing early-age shrinkage cracking on cementitious concrete. The overview describes the widely used ASTM C1579 (Standard Test Method for Evaluating Plastic Shrinkage Cracking of Restrained Fiber Reinforced Concrete (Using a Steel Form Insert) for plastic shrinkage cracking. The past literature used crack length, width, or area to describe and quantify cracks on concrete specimens. To keep things simple, this review expresses the length, width or area as a percentage of the control specimen. Finally, the study establishes a relationship between fiber volume and aspect ratio on plastic shrinkage and compressive strength of concrete. It was concluded that fiber is sufficient enough to mitigate plastic shrinkage cracking. An increase in fiber volume and aspect ratio reduces the early-age cracking of concrete but harm its compressive strength.

Understanding the behavior of soil under cyclic loading conditions is essential for assessing its response to seismic events and potential liquefaction. This study investigates the effect of non-plastic fines content (FC) on excess pore pressure generation in medium-density sand-silt mixtures subjected to strain-controlled cyclic direct simple shear (CDSS) tests. The investigation is conducted by analyzing excess pore pressure (EPP) ratios and the number of cycles to liquefaction (Ncyc-liq) under varying shear strain levels and FC values. The study uses Jumunjin sand and silica silt with FC values ranging from 0% to 40% and shear strain levels of 0.1%, 0.2%, 0.5%, and 1.0%. The findings indicate that the EPP ratio increases rapidly during loading cycles, with higher shear strain levels generating more EPP and requiring fewer cycles to reach liquefaction. At 1.0% and 0.5% shear strain levels, FC has a limited effect on Ncyc-liq. However, at a lower shear strain level of 0.2%, increasing FC from 0 to 10% reduces Ncyc-liq from 42 to 27, and as FC increases further, Ncyc-liq also increases. In summary, this study provides valuable insights into the behavior of soil under cyclic loading conditions. It highlights the significance of shear strain levels and FC values in excess pore pressure generation and liquefaction susceptibility.

In 2006, Cambodian Agriculture Research and Development Institute (CARDI) bred a high-quality tomato ‘Neang Pich’ variety. Since ‘Neang Pich’ is susceptible to Sclerotium rolfsii (S. rolfsii), it is severely affected the production major tomato growing regions. This study was conducted to evaluate the effect of seven S. rolfsii tolerant rootstocks on growth and yield in graft cultivation of ‘Neang Pich’ tomato. ‘Neang Pich’ seedlings were used as scion and non-grafted control. Six eggplant genotypes (‘2017053’, ‘2017062’, ‘17CJVC2’, ‘No. 80’, ‘VI041979A’, ‘VI041996’) and a commercial tomato variety (‘Hulk’) were used as rootstock. The grafted and non-grafted tomatoes were grown in a plastic greenhouse and open field. The survival rate of plants did not differ between plastic greenhouse (80.2%) and open field (79.5%). The top and root fresh weight of plants grown in a plastic greenhouse increased by 77% and 11% compared to the open field and the dry weight increased by 48% and 10%, respectively. The top (309 g) and root (18.9 g) fresh weight, and the top (90.5 g) and root (6.39 g) dry weight depending on rootstock were the highest in plants grafted onto ‘2017062’. The yield of tomatoes in a plastic greenhouse (19.5 MT/ha) was 65% higher than that of open field (11.8 MT/ha). The yield of tomatoes depending on rootstock were the highest in ‘2017062’ (17.8 MT/ha). The effect of cultivation practice and grafting on pH and sugar content (oBrix) of the fruit was non-significant difference (p0.05). The scion diameter, top fresh weight, fruit weight and yield (MT/ha) were significant difference (p0.05) in the interaction effect between tomato cultivation practices (plastic greenhouse and open field) and rootstock.

The tribology characteristics of the graphene coated PA6 were evaluated with scratch experiments. As a result, the following conclusions were obtained. The PA6 of the graphene coating shows a 0.1 improvement in friction coefficient and a lower abrasion depth than PA6 in the variable pressure-type scratch experiments. PA6 of the graphene coating showed a lower friction coefficient of 0.2 or more than PA6 in the friction coefficient in the static pressure scratch experiments, indicating that wear resistance was improved. In both the variable and the static pressure type scratch experiments, the tip depth of graphene-coated PA6 shows a thinner wear depth than PA6, showing the effect of graphene. The graphene content showed excellent tribology characteristics at 3%, and there was no difference in tribology characteristics at higher contents.

The need for lightweight yet strong materials is being demanded in all industries. Carbon fiber-reinforced plastic is a material with increased strength by attaching carbon fiber to plastic, and is widely used in the aerospace industry, ships, automobiles, and civil engineering based on its low density. Carbon-reinforced fiber plastic is a material widely used in parts and manufactured products, and structural analysis simulation is required during design, and application of actual material properties is necessary for accurate structural analysis simulation. In the case of carbon-reinforced fiber plastics, it is reported that there is a porosity of around 0.5% to 6%, and it is necessary to check the change in material properties according to the porosity and pore shape. It was confirmed by applying the method. It was confirmed that the change in elastic modulus according to the porosity was 10.7% different from the base material when the porosity was 6.0%, and the Poisson's ratio was confirmed to be less than 3.0%. It was confirmed that the elliptical spherical pore derived different material properties from the spherical pore depending on the pore shape, and it was confirmed that the shape of the pore had to be confirmed to derive equivalent material properties.

Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO2 enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO2 enrichment in greenhouse tomatoes. The growth of tomato treated with CO2 enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO2 was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO2 treatment group than control. CO2 enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.

This study aimed to develop an optimal greenhouse model for strawberry seedling during the summer high-temperature period based on the results of field surveys. We conducted a survey on the structure types of 46 strawberry seedling farms nationwide, including width, ridge height, eaves height, ventilation method, seedling bed width, and spacing. Based on the survey results, we derived the optimal greenhouse model by considering various factors. The greenhouse width was set at 14 meters to maximize the efficiency of seedling beds and overall space. The height was determined at 2 meters, taking into account ventilation during the summer season. To reduce stress on the supporting structure due to snow loads, we established a reinforcement installation angle of 50 degrees. We analyzed two different models that use support beams with dimensions of φ48.1×2.1t and φ59.9×3.2t, respectively, to ensure structural safety against meteorological disasters, considering regional design wind speeds and snow accumulation. We utilized these developed greenhouse model to conduct strawberry seedling experiments, resulting in a high survival rate of average 93.2%. These findings confirm the usefulness of the strawberry seedling greenhouse in improving the seedling environment and enhancing overall efficiency.

2022년부터 2023년까지 제주도내 키위 시설재배지를 대상으로 계절 초기 볼록총채벌레 발생 경향을 확인하 기 위해서 토양 표면의 잡초, 토양 표면 상단으로부터 60cm, 키위나무를 유인한 덕 상단 15cm에서 10일 간격으로 발생 조사하였다. 하우스 내부에서 발생하는 잡초 10종을 채집하여 조사한 결과, 갈퀴덩굴, 광대나물, 개불알풀, 별꽃, 뽀리뱅이, 황새냉이 6종에서 볼록총채벌레가 지속적으로 관찰되었다. 계절 초기 월동 성충의 비산시기를 확인하기 위해 토양 표면 60cm 위쪽에 설치한 황색 끈끈이트랩에서 2월 하순~3월 중순부터 볼록총채벌레의 발생을 확인하였다. 시설하우스 내부(덕 상단 15cm)와 외부(측장 높이)에 설치한 황색 끈끈이트랩을 비교해보면 시설 내·외부의 볼록총채벌레의 밀도가 증가하고 감소하는 시기가 유사하였다. 종합적인 고찰을 통하여, 발생 양상을 고려한 적절한 방제전략 수립이 요구된다.

In this study, we evaluate artificial neural network (ANN) models that estimate the positions of gamma-ray sources from plastic scintillating fiber (PSF)-based radiation detection systems using different filtering ratios. The PSF-based radiation detection system consists of a single-stranded PSF, two photomultiplier tubes (PMTs) that transform the scintillation signals into electric signals, amplifiers, and a data acquisition system (DAQ). The source used to evaluate the system is Cs-137, with a photopeak of 662 keV and a dose rate of about 5 μSv/h. We construct ANN models with the same structure but different training data. For the training data, we selected a measurement time of 1 minute to secure a sufficient number of data points. Conversely, we chose a measurement time of 10 seconds for extracting time-difference data from the primary data, followed by filtering. During the filtering process, we identified the peak heights of the gaussian-fitted curves obtained from the histogram of the time-difference data, and extracted the data located above the height which is equal to the peak height multiplied by a predetermined percentage. We used percentage values of 0, 20, 40, and 60 for the filtering. The results indicate that the filtering has an effect on the position estimation error, which we define as the absolute value of the difference between the estimated source position and the actual source position. The estimation of the ANN model trained with raw data for the training data shows a total average error of 1.391 m, while the ANN model trained with 20%-filtered data for the training data shows a total average error of 0.263 m. Similarly, the 40%-filtered data result shows a total average error of 0.119 m, and the 60%-filtered data result shows a total average error of 0.0452 m. From the perspective of the total average error, it is clear that the more data are filtered, the more accurate the result is. Further study will be conducted to optimize the filtering ratio for the system and measuring time by evaluating stabilization time for position estimation of the source.

지구의 약 2/3를 차지하는 바다는 수억 종 유기체의 터전이며 이산화탄소를 흡수하며 기후변화 완화에 중요한 역할을 한다. 또한 바다는 해양자원을 제공 하고 무역의 중요한 교통로 역할을 한다. 그러나 우리 삶과 매우 밀접한 관계 가 있는 해양이 플라스틱으로 인해 파괴되고 있다. 매일 800만 개의 쓰레기가 바다로 유입되어 다양한 해양 생물이 쓰레기에 얽히거나 쓰레기를 섭취함으로 써 직접적인 영향을 받고 있다. 이처럼 해양환경에 부정적 영향을 미치는 해양 플라스틱에 대응하기 위해 2022년 3월 나이로비에서 열린 유엔환경총회 (UNEA)에서는 해양 플라스틱을 직접적으로 규제하는 법적 구속력을 지닌 국 제조약을 제정하기로 합의하였다. 이는 해양 플라스틱으로 인해 날로 심각해지 고 있는 해양환경에 매우 긍정적이라 할 수 있다. 육지를 기반으로 한 해양오 염으로부터 해양환경을 보호하기 위한 국제사회의 노력은 수 세기 동안 연성법의 형태로 발전되어 왔다. 이런 연성법은 새로 제정될 해양 플라스틱 조약에 분명 제시하는 시사점이 있을 것이다. 그러므로 본 논문에서는 연성법의 내용 을 교리적 법률연구를 통해 살펴보고, 이를 통해 새로운 국제조약에 필수적으 로 포함되어야 할 규정에 대해 제안하고자 한다.

A fixed-point iteration is proposed to integrate the stress and state variables in the incremental analysis of plastic deformation. The Conventional Newton–Raphson method requires a second-order derivative of the yield function to generate a complicated code, and the convergence cannot be guaranteed beforehand. The proposed fixed-point iteration does not require a second-order derivative of the yield function, and convergence is ensured for a given strain increment. The fixed-point iteration is easier to implement, and the computational time is shortened compared with the Newton–Raphson method. The plane-stress condition is considered for the biaxial loading conditions to confirm the convergence of the fixed-point iteration. 3-dimensional tensile specimen is considered to compare the computational times in the ABAQUS/explicit finite element analysis.

국내 건설현장에서 장스팬 구조물이 증가함에 따라 콘크리트와 강재를 조합한 충전형합성보의 적용이 증가하고 있 다. 충전형합성보는 경제적이며 시공성이 향상되고 콘크리트 축열효과에 따라 내화성도 우수하다. 충전형합성보 내부에 휨성능 을 향상시키기 위해 Re-bar로 보강하여 사용한다. 이는 콘크리트 균열에 의해 부식 되어 내력저하를 유발한다. CFRP Re-bar는 경량이며 내부식성이 우수하다. 그러나 임계온도가 250℃로 낮기 때문에 화재에 취약으로 적절한 내화피복재를 적용해야된다. 따라서 열전달해석을 통해 내부 CFRP Re-bar가 보강된 충전형합성보의 온도분포를 확인하였다. 온도 상승에 따른 휨내력을 산 정하여 피복두께를 제안하고자 한다. 해석결과 단면크기에 상관없이 콘크리트 피복두께 40mm와 뿜칠내화피복재 20mm를 적용 하면 표준화재에서 3시간 내화성능을 확보하는 것으로 평가되었다.

In this work, we report a direct preparation of a few-walled carbon nanotube (FWCNTs) and NiMgAl composites namely FWCNT-NiMgAl by pyrolysis of waste high-density polyethylene (HDPE) plastic at 800 °C with NiMgAl-layered double hydroxide (LDH) as catalysts. The composite formation is carried out in a single step using our lab-developed pyrolysis reactor. The NiMgAl-LDH catalyst was prepared by co-precipitation method and the FWCNTs were grown on the NiMgAl-LDH catalyst with FWCNT yield of 10% and FWCNT-NiMgAl composite yield of 55% whose quality is determined by Raman ID/IG ratio of 2.57. The average outer and inner diameter of the FWCNT are found to be 5.5 nm and 2.9 nm, respectively, from TEM and 2.92 nm from the outer RBM (radial breathing mode) band, which indicates the formation of a few-walled CNTs. FWCNT-NiMgAl is used for the fabrication of flexible supercapacitor electrodes on a polyethylene terephthalate (PET) sheet which achieved a specific capacitance of 432 Fg− 1 in a wide potential range (ΔV = 2) at a scan rate of 5 mV s− 1 in 2 M KOH electrolyte with a high energy density of 240 Wh kg− 1, whereas NiMgAl displayed a capacitance of 200 Fg− 1 with an energy density of 111 Wh kg− 1. The diffusion-type charge storage mechanism (pseudocapacitance) is found to be dominant with contributions of 73.2% and 69.75% for NiMgAl and FWCNT-NiMgAl, respectively. The highest specific capacitance and energy density are obtained for NiMgAl in 2 M KCl and for FWCNT-NiMgAl in 2 M NaOH electrolytes. However, the largest potential window is observed in KOH electrolyte for both NiMgAl and FWCNT-NiMgAl with value of ΔV = 2 V. The electrode material shows good stability in acidic electrolytes and also shows good capacitive stability at high frequencies maintaining a phase angle of 70°. The present work is a novel approach to fabricate low-cost multifunctional carbon composite nanomaterials and will contribute to the research on low-cost waste-derived CNT composite preparation and its application in flexible energy storage devices.