RESIDUAL STRENGTH OF STRUCTURAL STEELS: SN400, SM520 AND SM570

This paper presents post-fire mechanical properties of mild to high-strength steels commonly used in building structures in Korea. Steel is one of the main materials for building construction due to fast construction, light weight, and high seismic resistance. However, steel usually loses its strength and stiffness at elevated temperatures, especially over 600°C. But steel can regain some of its original mechanical properties after cooling down from the fire. Therefore, it is important to accurately evaluate the reliable performance of steel to reuse or repair the structures. For this reason, an experimental study was performed to examine the post-fire mechanical properties of steel plates SN400, SM520 and SM570 after cooling down from elevated temperatures up to 900°C. The post-fire stress-strain curves, elastic modulus, yield and ultimate strengths and residual factors were obtained and discussed

Nanocomposite hydrogel actuators hybridized with various dimensional nanomaterials for stimuli responsiveness enhancement

Hydrogel actuators, that convert external energy, such as pH, light, heat, magnetic field, and ion strength, into mechanical motion, have been utilized in sensors, artificial muscles, and soft robotics. For a practicality of the hydrogel actuators in a wide range of fields, an establishment of robust mechanical properties and rapid response are required. Several solutions have been proposed, for example, setting porous and anisotropy structures to hydrogels with nanocomposite materials to improve the response speed and deformation efficiency. In this review paper, we focused on hydrogel actuators including various nanocomposite by categorizing the dimensional aspects of additive materials. Moreover, we described the role of diverse additive materials in terms of the improvement of mechanical property and deformation efficiency of the hydrogel actuators. We assumed that this review will provide a beneficial guidance for strategies of developing nanocomposite hydrogel actuators and outlooks for the future research directions.11Ysciescopu

カンコク ヘナム グン ノ ベイサク ノウカ ニ オケル キコウ ヘンドウ ノ ニンシキ ニ カンスル ブンセキ

本研究では韓国ヘナム郡の米作農家における気候変動の認識に関して分析した。ロジットモデルとプロビットモデルを用いて、気候変動の認識の決定要素を検定した。結果として、米作農家の気候変動の認識は高いこと(83.6%)が示された。年齢については負の値であり、高齢者であるほど認識が少ない。つまり若年層が強く気候変動を認識していた。教育については正の値であり、高学歴であるほど強く気候変動を認識していた。そして気候情報の入手については正の値であり、情報アクセスを改善することによって、強く気候変動を認識させることができると分かった。本研究から気候変動情報、教育、訓練における適切な政策プログラムが提供される。This study analyzes perception to climate change of rice farmers in Haenam district, Korea. A logit model and a probit model are used to examine the determinants of perception to climate change. The results indicate that rice farmers\u27 perception of climate change appear to be high(83.6 percent). The findings indicate that age, education and access to climate information have a significant impact on perception to climate change. This study provides some appropriate policy program of information on climate change, education and training

Recurred pneumocephalus in a head trauma patient following positive pressure mask ventilation during induction of anesthesia -A case report-

Pneumocephalus is a condition which usually results from head trauma. It has been known that iatrogenic pneumocephalus can occur as a complication of positive pressure mask ventilation during induction of anesthesia or ventilatory care for head trauma patients. We report a case of mask ventilation during anesthesia induction in a 50-year-old male patient with head trauma. Initial pneumocephalus associated with cerebrospinal fluid leakage was diagnosed immediate following head injury involving facial sinuses. He was managed with emergent lumbar drainage and supportive care. Pneumocephalus recurred following positive pressure mask ventilation (PPMV) during anesthesia induction for surgery on the right arm. Recurred pneumocephalus was managed with high flow oxygen and supportive care. Anesthesiologists should be aware of pneumocephalus as a potential complication of PPMV in head trauma patients, even after resolution of previous pneumocephalus

Ductographic Findings of Breast Cancer

Ductography has become the gold standard for the evaluation of patients exhibiting pathologic nipple discharges. In nine patients (age range, 29-67 years; median age, 51 years) with invasive (n=5) or intraductal (n=4) cancer, ductographic findings were recorded, then correlated with mammographic and sonographic findings. Common ductographic findings included complete ductal obstruction, multiple irregular filling defects in the nondilated peripheral ducts, ductal wall irregularities, periductal contrast extravasation, and ductal displacement. Faint microcalcifications or ill-defined masses, which were not opacified by contrast material, were often discovered adjacent to ductal abnormalities. Mammographically and sonographically occult diffusely spreading intraductal cancers often manifested as pathologic nipple discharge. In such cases, meticulous ductographic examinations and interpretations were crucial in order not to miss breast cancers