• Title/Summary/Keyword: thermal studies

Search Result 1,822, Processing Time 0.024 seconds

Thermal Characteristics of Epoxy-Nanocomposites filled Several Types Nano Layered Silicate Particles (나노층상실리케이트가 충진된 에폭시-나노콤포지트의 열적특성 연구)

  • Park, Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.21 no.8
    • /
    • pp.749-754
    • /
    • 2008
  • A large number of studies on the various characteristics of epoxy-layered silicate nanocomposites, such as electric and mechanical, morphology have been conducted and contributed to improve their characteristics. However, studies on the effects of its thermal conductivities in the thermal properties are not enough, even though there are some excellent evaluations for its insulation performances. Thermal properties will cause thermal degradation and significantly affect the reliability of these epoxy-layered silicate nanocomposites. In the results of the analysis of epoxy-layered silicate nanocomposites $T_g$ for various types of organoclays (10A, 15A, 20A, 30B, and 93A), it showed an excellent thermal property of 10A. Also, it represented low values in storage modulus and mechanical Tan (Delta) at a high temperature section 140$^{\circ}C$ and excellent thermal properties due to its movement to the high temperature section in the case of the property of 10A in the measurement of DMA elastics and mechanical losses. In the results of the measurement of thermal conductivities, power ultrasonic applications represented a significant increase in thermal conductivities in the case of the applications of power ultrasonic and planetary centrifugal mixers. Based on these results, it is necessary to perform related studies because it can be applied as useful materials for future power facilities applications in mold and impregnate insulation.

Effect of Bentonite Type on Thermal Conductivity in a HLW Repository

  • Lee, Gi-Jun;Yoon, Seok;Cho, Won-Jin
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.19 no.3
    • /
    • pp.331-338
    • /
    • 2021
  • Extensive studies have been conducted on thermal conductivity of bentonite buffer materials, as it affects the safety performance of barriers engineered to contain high-level radioactive waste. Bentonite is composed of several minerals, and studies have shown that the difference in the thermal conductivity of bentonites is due to the variation in their mineral composition. However, the specific reasons contributing to the difference, especially with regard to the thermal conductivity of bentonites with similar mineral composition, have not been elucidated. Therefore, in this study, bentonites with significantly different thermal conductivities, but of similar mineral compositions, are investigated. Most bentonites contain more than 60% of montmorillonite. Therefore, it is believed that the exchangeable cations of montmorillonite could affect the thermal conductivity of bentonites. The effect of bentonite type was comparatively analyzed and was verified through the effective medium model for thermal conductivity. Our results show that Ca-type bentonites have a higher thermal conductivity than Na-type bentonites.

Thermal Infrared Remote Sensing Data Utilization for Urban Heat Island and Urban Planning Studies

  • Lee, Hye Kyung
    • Journal of KIBIM
    • /
    • v.7 no.2
    • /
    • pp.36-43
    • /
    • 2017
  • Population growth and rapid urbanization has been converting large amounts of rural vegetation into urbanized areas. This human induced change has increased temperature in urban areas in comparison to adjacent rural regions. Various studies regarding to urban heat island have been conducted in different disciplines in order to analyze the environmental issue. Especially, different types of thermal infrared remote sensing data are applied to urban heat island research. This article reviews research focusing on thermal infrared remote sensing for urban heat island and urban planning studies. Seven studies of analyses for the relationships between urban heat island and other dependent indicators in urban planning discipline are reviewed. Despite of different types of thermal infrared remote sensing data, units of analysis, land use and land cover, and other dependent variable, each study results in meaningful outputs which can be implemented in urban planning strategies. As the application of thermal infrared remote sensing data is critical to measure urban heat island, it is important to understand its advantages and disadvantages for better analyses of urban heat island based on this review. Despite of its limitations - spatial resolution, overpass time, and revisiting cycle, it is meaningful to conduct future research on urban heat island with thermal infrared remote sensing data as well as its application to urban planning disciplines. Based on the results from this review, future research with remotely sensed data of urban heat island and urban planning could be modified and better results and mitigation strategies could be developed.

Assessment on Thermal Environment and Human Thermal Comfort in Residential Building Block through Field Measurement (실측을 통한 공동주택 단지 내에서의 온열환경 및 거주자 쾌적감 평가에 관한 연구)

  • Lim, Jong-Yeon;Hwang, Hyo-Keun;Song, Doo-Sam;Kim, Tae-Yeon
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2008.04a
    • /
    • pp.311-317
    • /
    • 2008
  • As outdoor environment become worse due to concentration of population in large cities, the importance of environmental control strategies such as the arrangement of green space or water space and ventilation paths, has been increasingly recognized. However, most of the studies focus on the assessment on outdoor thermal environment, few studies focus on the interrelationship between thermal environment in residential block and human thermal comfort. The aims of this study is to develop the outdoor planning method to reduce the heating/cooling load in an apartment unit or entire block by the sustainable approaches in outdoor environmental design. In this paper, on the basis of the prior studies, the effect of the outdoor thermal environment on human thermal comfort will be analysed.

  • PDF

Thermal Strain Measurement of Austin Stainless Steel (SS304) during a Heating-cooling Process

  • Ha, Ngoc San;Le, Vinh Tung;Goo, Nam Seo;Kim, Jae Young
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.18 no.2
    • /
    • pp.206-214
    • /
    • 2017
  • In this study, measurement of thermophysical properties of materials at high temperatures was performed. This experiment employed a heater device to heat the material to a high temperature. The images of the specimen surface due to thermal load at various temperatures were recorded using charge-coupled device (CCD) cameras. Afterwards, the full-field thermal deformation of the specimen was determined using the digital image correlation (DIC) method. The capability and accuracy of the proposed technique are verified by two experiments: (1) thermal deformation and strain measurement of a stainless steel specimen that was heated to $590^{\circ}C$ and (2) thermal expansion and thermal contraction measurements of specimen in the process of heating and cooling. This research focused on two goals: first, obtaining the temperature dependence of the coefficient of thermal expansion, which can be used as data input for finite element simulation; and second, investigating the capability of the DIC method in measuring full-field thermal deformation and strain. The results of the measured coefficient of thermal expansion were close to the values available in the handbook. The measurement results were in good agreement with finite element method simulation results. The results reveal that DIC is an effective and accurate technique for measuring full-field high-temperature thermal strain in engineering fields such as aerospace engineering.

Applications of Non-Thermal Atmospheric Pressure Plasma in Dentistry (상온 대기압 플라즈마의 치의학적 응용)

  • Uhm, Soo-Hyuk;Kwon, Jae-Sung;Lee, Eun-Jung;Lee, Jung-Hwan;Kim, Kyoung-Nam
    • The Journal of the Korean dental association
    • /
    • v.52 no.12
    • /
    • pp.783-794
    • /
    • 2014
  • Since the introduction of non-thermal atmospheric pressure plasma in the field of the dentistry, numerous applications have been investigated. Especially with its advantages over existing vacuum plasma in terms of portability, low cost, and non-thermal damage, it can be directly applied in the oral cavity, giving number of potentials for dental application. First, possible application of non-thermal atmospheric pressure plasma in the field of dentistry is relation to dental caries and periodontal diseases. Teeth and alveolar bones are one of the strongest bony structures in our body, but it cannot be regenerated when they are damaged by dental caries or periodontal disease. Hence many studies to prevent such diseases have been carried out, though no perfect solution has been found yet. With recent studies of modifying surfaces through non-thermal atmospheric pressure application that can prevent attachment of bacteria, or studies on bactericidal effects of non-thermal atmospheric pressure plasma can be applied here to prevent oral pathogen and 'biofilm' attachment to the surface of teeth or directly eliminate the dental caries/periodontal disease causing germs. Secondly, non-thermal atmospheric pressure application will be useful on the surface of dental implant. It is well known that the success of dental implant surgery depends on the process known as 'osseointegration' that result from osteoblast attachment, proliferation and differentiation. As the application of non-thermal atmospheric pressure plasma on the surface of dental implant just before its introduction by the chair-side of dental surgery. Despite its long history, the generation of non-thermal atmospheric pressure plasma has been greatly increased with its application in dentistry.

Comparison of Thermal Ablation and Surgery for Low-Risk Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

  • Hyun Jin Kim;Se Jin Cho;Jung Hwan Baek
    • Korean Journal of Radiology
    • /
    • v.22 no.10
    • /
    • pp.1730-1741
    • /
    • 2021
  • Objective: Although thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), comparison of treatment outcomes between thermal ablation and surgery has not yet been systematically evaluated. This study aimed to compare the efficacy and safety of thermal ablation and surgery for the treatment of low-risk PTMCs. Materials and Methods: Ovid-MEDLINE and EMBASE databases were searched for studies reporting comparisons of treatment results between thermal ablation and surgery for patients with low-risk PTMC published up to April 6, 2020. The analysis evaluated the efficacy (local tumor recurrence, occurrence of new tumor, metastasis, and rescue surgery) and safety (complication rate) of thermal ablation and surgery. Results: This systematic review included four studies with a total of 339 PTMCs in 339 patients who underwent thermal ablation and 320 PTMCs in 314 patients who underwent surgery. There was no local tumor recurrence or distant metastasis in either group. There was no significant difference in the pooled proportion of lymph node metastasis (2.6% with thermal ablation vs. 3.3% with surgery, p = 0.65), occurrence of new tumors (1.4% with thermal ablation vs. 1.3% with surgery, p = 0.85), or rescue surgery (2.6% with thermal ablation vs. 1.6% with surgery, p = 0.62). However, the pooled complication rate was significantly higher in the surgery group than in the ablation group (3.3% with thermal ablation vs. 7.8% with surgery, p = 0.03). Conclusion: Both thermal ablation and surgery are effective and safe options for the management of low-risk PTMCs, with thermal ablation achieving a lower complication rate. Therefore, thermal ablation may be considered as an alternative treatment option for low-risk PTMC in patients who refuse surgery and active surveillance or are ineligible for surgery.

Thermal irritation of teeth during dental treatment procedures

  • Kwon, Su-Jung;Park, Yoon-Jung;Jun, Sang-Ho;Ahn, Jin-Soo;Lee, In-Bog;Cho, Byeong-Hoon;Son, Ho-Hyun;Seo, Deog-Gyu
    • Restorative Dentistry and Endodontics
    • /
    • v.38 no.3
    • /
    • pp.105-112
    • /
    • 2013
  • While it is reasonably well known that certain dental procedures increase the temperature of the tooth's surface, of greater interest is their potential damaging effect on the pulp and tooth-supporting tissues. Previous studies have investigated the responses of the pulp, periodontal ligament, and alveolar bone to thermal irritation and the temperature at which thermal damage is initiated. There are also many in vitro studies that have measured the temperature increase of the pulp and tooth-supporting tissues during restorative and endodontic procedures. This review article provides an overview of studies measuring temperature increases in tooth structures during several restorative and endodontic procedures, and proposes clinical guidelines for reducing potential thermal hazards to the pulp and supporting tissues.

The information system concept for thermal monitoring of a spent nuclear fuel storage container

  • Svitlana Alyokhina
    • Nuclear Engineering and Technology
    • /
    • v.55 no.10
    • /
    • pp.3898-3906
    • /
    • 2023
  • The paper notes that the most common way of handling spent nuclear fuel (SNF) of power reactors is its temporary long-term dry storage. At the same time, the operation of the dry spent fuel storage facilities almost never use the modern capabilities of information systems in safety control and collecting information for the next studies under implementation of aging management programs. The author proposes a structure of an information system that can be implemented in a dry spent fuel storage facility with ventilated storage containers. To control the thermal component of spent fuel storage safety, a database structure has been developed, which contains 5 tables. An algorithm for monitoring the thermal state of spent fuel was created for the proposed information system, which is based on the comparison of measured and forecast values of the safety criterion, in which the level of heating the ventilation air temperature was chosen. Predictive values of the safety criterion are obtained on the basis of previously published studies. The proposed algorithm is an implementation of the information function of the system. The proposed information system can be used for effective thermal monitoring and collecting information for the next studies under the implementation of aging management programs for spent fuel storage equipment, permanent control of spent fuel storage safety, staff training, etc.

A Review of the Domestic Study Trends on Obstetrics & Gynecological Diseases by Using Digital Infrared Thermal Imaging as a Diagnosis Instrument (한방여성의학 영역에서 진단 도구로 적외선 체열 검사(Digital Infrared Thermal Imaging, DITI)를 활용한 국내 연구 동향 분석)

  • Im, Ji-Yeong;Hwang, Deok-Sang;Lee, Jin-Moo;Lee, Chang-Hoon;Jang, Jun-Bock
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.33 no.3
    • /
    • pp.80-94
    • /
    • 2020
  • Objectives: The purpose of this review is to analyze the domestic study trends of clinical use of Digital Infrared Thermal Imaging (DITI) as a diagnosis instrument on obstetrics and gynecological diseases in Korean literature. Methods: We searched for clinical studies using DITI in the journal of Korean obstetrics & gynecology, National Digital Science Library, Research Information Sharing Service, Korean Medical Database up to May 2020. After searching studies, we selected studies and analyzed according to disease. Results: 18 clinical studies were published in two kinds of academic journals. There were 4 studies about dysmenorrhea and menopausal symptoms, 2 studies about postpartum disease and hypercryalgesia, 1 study about amenorrhea, premenstrual syndrome, leukorrhea, infertility, polycystic ovary syndrome and hot flush. Conception vessel was frequently used for DITI measurement, followed by stomach meridian. The temperatures of abdomen (CV4, CV12), face (HN3), upper and lower limb (PC8, LU4, LR3, ST32) were commonly measured. Conclusions: This study shows that DITI could be one of effective diagnosis instrument for obstetrics and gynecological diseases. More well-designed clinical studies using DITI will be needed.