• Title/Summary/Keyword: temperature limit

Search Result 1,360, Processing Time 0.029 seconds

Convergence Study on the Thermal Stress According to the Structure of Automotive Heating Seat (자동차 난방 시트의 구조에 따른 열응력 해석에 대한 융합 연구)

  • Choi, Gye-Gwang;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
    • /
    • v.10 no.7
    • /
    • pp.169-174
    • /
    • 2019
  • Because the warm and cozy demand of automotive driving seat increases, the research development of heating seat has been actively made. In this study, the thermal stress analysis and the structural analysis were carried out with three kinds of heating seats of A, B and C. By executing the thermal analysis with the same material, model A was shown to have the heat transfer better than model B or model C at the study result. So, it could be seen that the heat transfers became different each other though models had the same material according to the configuration of product. Adding the hot wire in order to expect the safer heating can be better heating, but there is the limit on the aspect considering the capability in contrast to the price of product. Generally, model B is thought to be safest thermally than model A or model C in every respect. As the design data of the automotive heating seat product with the durability and safety acquired by this study result are used, the artistic environment can be promoted by being grafted onto the automotive driving seat.

Studies on mycotoxins using LC-MS/MS for the forage produced in Incheon

  • Ra, Do Kyung;Choi, Jae Yeon;Lee, Ju Ho;Nam, Ji Hyun;Lee, Jeoung Gu;Lee, Sung Mo
    • Korean Journal of Veterinary Service
    • /
    • v.42 no.3
    • /
    • pp.127-133
    • /
    • 2019
  • The purpose of this study was to investigate the contamination level of representative mycotoxins that have adverse effects on livestock by using LC-MS/MS method and to utilize the results as basic data for the establishment of quality control system for feed, and to provide information on production and storage. A total of nine mycotoxins, including aflatoxin $B_1$, aflatoxin $B_2$, aflatoxin $G_1$, aflatoxin $G_2$, ochratoxin A, fumonisin $B_1$, fumonisin $B_2$, deoxynivalenol (DON), zearalenone (ZEN) were simultaneously analyzed in LC-MS/MS under ESI positive mode. Fumonisin $B_1$ and fumonisin $B_2$ were detected from 3 cases of 75 forage produced in Incheon area, the detection rate was 4.0%. The detection concentration was 0.01~0.02 mg/kg, which was lower than the domestic recommended limit. Fumonisins were detected in a slightly different manner from the results of mycotoxin studies reported in Korea, which is attributed to the high temperature and dry summer weather of the year. The result of LC-MS/MS method performance of 9 mycotoxins, the recovery of DON was quite low as $41.53{\pm}3.91%$ that is not suitable for simultaneous analysis. This is probably due to that the extract solution used in this study was not suitable for the extraction of DON, along with the characteristics of a very dry forage. For the study of mycotoxins in Incheon area forage for the first time, further investigation is needed for the safe supply of livestock products.

Current status and issues on prevention from the biological damage of cultural property (국내 문화재 생물피해 방제의 현황과 과제)

  • Choi, Yu Ri;Kang, Dai Ill
    • Korean Journal of Heritage: History & Science
    • /
    • v.48 no.3
    • /
    • pp.138-153
    • /
    • 2015
  • For preventing the biological damage domestically, insect damage control method using chemical medicine has been applied. However, it is trend to avoid existing chemical medicine such as Methyl bromide because of the problem of being harmful to human body and environment. Therefore, the research for new medicine to replace this has been done and the interest to the physical treatment such as temperature(high & low) treatment, hypoxic treatment, carbon dioxide treatment, and radiation treatment has increased. However the systematic application standard and way has not been established. Therefore, in this research, we are going to organize present condition of domestic cultural asset preventing biological damage after the 1980's. It will also consider the direction through the characteristic of technology, limit, and replacement medicine by examining the past research.

The Design of Application Model using Manufacturing Data in Protection Film Process for Smart Manufacturing Innovation (스마트 제조혁신을 위한 보호필름 공정 제조데이터의 활용모델 설계)

  • Cha, ByungRae;Park, Sun;Lee, Seong-ho;Shin, Byeong-Chun;Kim, JongWon
    • Smart Media Journal
    • /
    • v.8 no.3
    • /
    • pp.95-103
    • /
    • 2019
  • The global manufacturing industry has reached the limit to growth due to a long-term recession, the rise of labor cost and raw material. As a solution to these difficulties, we promote the 4th Industry Revolution based on ICT and sensor technology. Following this trend, this paper proposes the design of a model using manufacturing data in the protection film process for smart manufacturing innovation. In the protective film process, the manufacturing data of temperature, pressure, humidity, and motion and thermal image are acquired by various sensors for the raw material blending, stirring, extrusion, and inspection processes. While the acquired manufacturing data is stored in mass storage, A.I. platform provides time-series image analysis and its visualization.

Thermal buckling analysis of embedded graphene-oxide powder-reinforced nanocomposite plates

  • Ebrahimi, Farzad;Nouraei, Mostafa;Dabbagh, Ali;Rabczuk, Timon
    • Advances in nano research
    • /
    • v.7 no.5
    • /
    • pp.293-310
    • /
    • 2019
  • In this paper, thermal-buckling behavior of the functionally graded (FG) nanocomposite plates reinforced with graphene oxide powder (GOP) is studied under three types of thermal loading once the plate is supposed to be rested on a two-parameter elastic foundation. The effective material properties of the nanocomposite plate are considered to be graded continuously through the thickness according to the Halpin-Tsai micromechanical scheme. Four types of GOPs' distribution namely uniform (U), X, V and O, are considered in a comparative way in order to find out the most efficient model of GOPs' distribution for the purpose of improving the stability limit of the structure. The governing equations of the plate have been derived based on a refined higher-order shear deformation plate theory incorporated with Hamilton's principle and solved analytically via Navier's solution for a simply supported GOP reinforced (GOPR) nanocomposite plate. Some new results are obtained by applying different thermal loadings to the plate according to the GOPs' negative coefficient of thermal expansion and considering both Winkler-type and Pasternak-type foundation models. Besides, detailed parametric studies have been carried out to reveal the influences of the different types of thermal loading, weight fraction of GOP, aspect and length-to-thickness ratios, distribution type, elastic foundation constants and so on, on the critical buckling load of nanocomposite plates. Moreover, the effects of thermal loadings with various types of temperature rise are investigated comparatively according to the graphical results. It is explicitly shown that the buckling behavior of an FG nanocomposite plate is significantly influenced by these effects.

Validation of Sanitation Management Standards for Vegetable Preparation with No-Cook Step Based on Microbiological Analysis (미생물 분석에 의한 채소류 비가열 조리공정의 위생관리 기준 유효성 평가)

  • Kim, Won-Kyeong;Ryu, Kyung
    • Journal of the Korean Dietetic Association
    • /
    • v.27 no.1
    • /
    • pp.45-58
    • /
    • 2021
  • This study evaluated the sanitation management standards for vegetable preparation processes without a cooking stage. The aerobic plate counts (APC), coliform counts, and Escherichia coli of the samples at each production step were analyzed, and microbial growth of the samples stored at different temperatures was measured. The validation was judged in accordance with the microbial criteria stipulated by the British PHLS. After washing and disinfection, the APCs of the two samples decreased to 3~4 log CFU/g in both seasons. Compared to the purchasing stage, the decrease in coliform counts was approximately 0~3 log CFU/g in both seasons; E. coli was not detected. The initial APC and coliform levels of two vegetable samples were 4~5 log CFU/g in both seasons, with an increase of 1 log CFU/g taking more than 6 h at 25℃ and 2 h at 35℃. More than 10 h at 25℃ and 6 h at 35℃ were required to increase the E. coli O157:H7 count by 1~2 log CFU/g for two seasoned samples. In conclusion, washing and disinfection effects and changes in microbial growth during room temperature storage were similar in the two vegetables. Despite the low sanitizing effect of the two vegetables, when cut vegetables were stored under the critical limit within 2 h at two different room temperatures, seasoned lettuce and chicory were at the 'satisfactory' or 'acceptable' levels of PHLS regardless of the storage temperatures. The validation of sanitation management standards applied to vegetable preparation with the no-cook step was approved.

Preparation and Characterization of Ordered Perovskite (CaLa) (MgMo) $_6$

  • Choy, Jin-Ho;Hong, Seung-Tae;Suh, Hyeong-Mi
    • Bulletin of the Korean Chemical Society
    • /
    • v.9 no.6
    • /
    • pp.345-349
    • /
    • 1988
  • The polycrystalline powder of (CaLa) (MgMo)$O_6$ has been prepared at $1350^{\circ}C$ in $H_2/H_2O$ and $N_2$ flowing atmosphere. The powder X-ray diffraction pattern indicates that (CaLa) (MgMo)$O_6$ has a monoclinic perovskite structure with the lattice constants $a_0=b_0=7.901(1){\AA}$, $c =7.875(1){\AA}\;and\;{\gamma}=89^{\circ}$16'(1'), which can be reduced to orthorhombic unit cell, a = 5.551(1) ${\AA}$, b = 5.622(1) ${\AA}$ and c = 7.875(1) ${\AA}$. The infrared spectrum shows two strong absorption bands with their maxima at 590($ν_3$) and 380($ν_4$) cm, which are attributed to $2T_{1u}$ modes indicating the existence of highly charged molybdenum octahedron $MoO_6$ in the crystal lattice. According to the magnetic susceptibility measurement, the compound follows the Curie-Weiss law below room temperature with the effective magnetic moment 1.83(1)$_{{\mu}B}$, which is well consistent with that of spin only value (1.73 $_{\mu}_B$) for $Mo^{5+}$ with $4d^1$-electronic configuration within the limit of experimental error. From the thermogravimetric analysis, it has been confirmed that (CaLa) (MgMo)$O_6$ decomposes gradually into $CaMoO_4,\;MoO_3,\;MgO,\;La_2O_3$ and unidentified phases due to the oxidation of $Mo^{5+}$ to $Mo^{6+}$.

Photostability evaluation of Jawarishe Jalinoos

  • Shahnawaz, Shahnawaz;Rahman, Khaleequr;Sultana, Arshiya;Sultana, Shabiya
    • CELLMED
    • /
    • v.11 no.4
    • /
    • pp.18.1-18.8
    • /
    • 2021
  • Jawarishe Jalinoos (JJ) is an orally used formulation available in semisolid dosage form, prepared with powdered plant materials mixed in honey or sugar syrup. It has many admirable pharmacological effects and used in Unani medicine to treat various acute and chronic disorders since ancient times. The ICH Harmonised Tripartite Guideline stated that photostability testing should be an essential part of stability testing to confirm that light exposure does not result in an unacceptable change in drugs substance and finished products. To date, the effect of light on JJ is not studied, in this study photostability evaluation of JJ was carried out. The test sample was manufactured with genuine ingredients in the in-door pharmacy of the National Institute of Unani Medicine. JJ was packed in two transparent polyethylene terephthalate airtight containers. The first sample was analysed at zero-day and the second sample was placed in a stability chamber subjected to light challenge with an overall illumination of 1.2 million lux hours combined with near ultraviolet energy of 200-watt hours per square meter by using option 2, along with 30±2℃ temperature and relative humidity 70±5%. Analysis of both finished products showed no considerable changes in organoleptic characters. Less than 5% variation was observed in physicochemical parameters. HPTLC fingerprinting showed justifiable variation. Microbial load and specific counts were within the limit prescribed by WHO. As no unacceptable changes were noted in JJ subjecting to light challenge, it is concluded that JJ is a photostable Unani compound formulation.

Liquid Metal Enabled Thermo-Responsive Poly(N-isopropylacrylamide)Hydrogel for Reversible Electrical Switch (액체금속이 첨가된 온도 감응성 poly(N-isopropylacrylamide) 하이드로젤의 전기적 특성 변화 고찰)

  • Lim, Taehwan;Lee, Sohee;Yeo, Sang Young
    • Textile Coloration and Finishing
    • /
    • v.34 no.3
    • /
    • pp.207-216
    • /
    • 2022
  • Hydrogels have gained considerable attention in various fields due to their easily transformative ability by different stimulation. In addition, metal-based conductive additives can enable the hydrogels to be conductive with dimension change. Although the development of the additives offered enhanced electrical properties to the hydrogels, correspondingly enhanced mechanical properties may limit the volume and electrical properties switching after stimulation. Here we prepared poly(N-isopropylacrylamide) (PNIPAM) thermo-responsive hydrogel that has a 32℃ of low critical solution temperature and added liquid metal particles (LMPs) as conductive additives, possessing soft and stretchable benefits. The LMPs enabled PNIPAM (PNIPAM/LMPs) hydrogels to be constricted over 32℃ with a high volume switching ratio of 15.2 when deswelled. Once the LMPs are spontaneously oxidized in hydrogel culture, the LMPs can release gallium ions into the hydrogel nature. The released gallium ions and oxidized LMPs enhanced the modulus of the PNIPAM/LMPs hydrogel, triggering high mechanical stability during repeated swelling/deswelling behavior. Lastly, highly constricted PNIPAM/LMPs hydrogel provided a 5x106 of electrical switching after deswelling, and the switching ratio was closely maintained after repeated swelling/deswelling transformation. This study opens up opportunities for hydrogel use requiring thermo-responsive and high electrical switching fields.

Northern distribution limits and future suitable habitats of warm temperate evergreen broad-leaved tree species designated as climate-sensitive biological indicator species in South Korea

  • Sookyung, Shin;Jung-Hyun, Kim;Duhee, Kang;Jin-Seok, Kim;Hong Gu, Kang;Hyun-Do, Jang;Jongsung, Lee;Jeong Eun, Han;Hyun Kyung, Oh
    • Journal of Ecology and Environment
    • /
    • v.46 no.4
    • /
    • pp.292-303
    • /
    • 2022
  • Background: Climate change significantly influences the geographical distribution of plant species worldwide. Selecting indicator species allows for better-informed and more effective ecosystem management in response to climate change. The Korean Peninsula is the northernmost distribution zone of warm temperate evergreen broad-leaved (WTEB) species in Northeast Asia. Considering the ecological value of these species, we evaluated the current distribution range and future suitable habitat for 13 WTEB tree species designated as climate-sensitive biological indicator species. Results: Up-to-date and accurate WTEB species distribution maps were constructed using herbarium specimens and citizen science data from the Korea Biodiversity Observation Network. Current northern limits for several species have shifted to higher latitudes compared to previous records. For example, the northern latitude limit for Stauntonia hexaphylla is higher (37° 02' N, Deokjeokdo archipelago) than that reported previously (36° 13' N). The minimum temperature of the coldest month (Bio6) is the major factor influencing species distribution. Under future climate change scenarios, suitable habitats are predicted to expand toward higher latitudes inland and along the western coastal areas. Conclusions: Our results support the suitability of WTEB trees as significant biological indicators of species' responses to warming. The findings also suggest the need for consistent monitoring of species distribution shifts. This study provides an important baseline dataset for future monitoring and management of indicator species' responses to changing climate conditions in South Korea.