• Title/Summary/Keyword: Nuclear architecture

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Composition Changes in Cement Matrix of RC Column Exposed to Fire (화재에 노출된 RC기둥 시멘트 매트릭스의 구성성분 변화)

  • Kim, Jung-Joong;Youm, Kwang-Soo
    • Journal of the Korea Concrete Institute
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    • v.26 no.3
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    • pp.369-375
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    • 2014
  • This study examined the changes of microstructural compositions in cement matrix according to the depth from the surface of a reinforced concrete (RC) column exposed to fire. The RC column was exposed to a standard fire for 180 minutes. After the fire test, core samples passing through the column section were obtained. Using the core samples, the remaining fractions of calcium-silicate-hydrates (C-S-H) and calcium hydroxide in cement matrix at the surface, the depth of 40 mm and 80 mm and the center (175 mm) were examined using thermal gravimetric analysis (TGA) and X-ray diffraction analysis (XRDA). Using nuclear magnetic resonance (NMR) technique, the silicate polymerization of C-S-H in cement matrix was also evaluated. The experimental results indicated that the amount of C-S-H loss at the center of column experiencing the transferred fire temperature of $236^{\circ}C$ has been underestimated as the TGA results showed the highest C-S-H contents are located at the depth of 80 mm, where the transferred fire temperature is $419^{\circ}C$. Moreover, the destruction of silicate connections at the center was observed as similar as that at the depth of 40 mm, where the transferred fire temperature was $618^{\circ}C$. This might be attributed to the temperature changes during cooling time after the fire test was neglected. Due to the relatively low thermal conductivity of concrete, the high temperature, which can affect the change of microstructure in cements, will hold longer at the center of the column than other depth.

A Numerical Model to Evaluate Fire-Resistant Capacity of the Reinforced Concrete Members (화재에 손상된 철근콘크리트 부재의 수치모델 및 내화성능해석)

  • Hwang, Jin-Wook;Ha, Sang-Hee;Lee, Yong-Hoon;Kim, Wha-Jung;Kwak, Hyo-Gyoung
    • Journal of the Korea Concrete Institute
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    • v.25 no.5
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    • pp.497-508
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    • 2013
  • This paper introduces a numerical model which can evaluate the fire-resistant capacity of reinforced concrete members. On the basis of the transient heat transfer considering the heat conduction, convection and radiation, time-dependent temperature distribution across a section is determined. A layered fiber section method is adopted to consider non-linear material properties depending on the temperature and varying with the position of a fiber. Furthermore, effects of non-mechanical strains of each fiber like thermal expansion, transient strain and creep strain are reflected on the non-linear structural analysis to take into account the extreme temperature variation induced by the fire. Analysis results by the numerical model are compared with experimental data from the standard fire tests to validate an exactness of the introduced numerical model. Also, time-dependent changes in the resisting capacities of reinforced concrete members exposed to fire are investigated through the analyses and, the resisting capacities evaluated are compared with those determined by the design code.

An Experimental Study on the Development of Electromagnetic Shielding Concrete Wall for Shielding High-altitude Electromagnetic Pulse (HEMP) (고고도 전자기파(HEMP)차폐를 위한 전자파 차폐 콘크리트 벽체 개발에 관한 실험적 연구)

  • Choi, Hyun-Jun;Kim, Hyung-Chul;Lim, Sang-Woo;Lee, Han-Seung
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.169-177
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    • 2017
  • Rather than causing damage from heat, blast, and radiation of a regular nuclear weapon, recently, it is predicted that North Korea has been inventing high altitude electromagnetic pulse (HEMP) missile in order to incapacitate electronic equipment. HEMP shielding facility is used for military purpose today. Despite the electromagnetic shielding effects from high quality compression plates, problems may include such as the possibility of electromagnetic influx resulting in the welding of the compression plates, and difficulties and high cost of construction. Therefore, in this study, a high electrical conducting material was added to the concrete experimental subject to ensure the shielding effect through electromagnetic waves to for the concrete structure, instead of building a shielding facility separately for the structure. Also, among the experimental subjects, 100 ${\mu}m$ of Iron-Aluminum alloy metal spraying coat was applied to two types with the highest shielding effect, and to two types with the lowest shielding effect. The result of the experiment indicates that experimental subjects added with a high electrical conductivity material did not meet the minimum shielding criteria of MIL-STD-118-125-1 standard, but all the experimental material applied to the metal spraying coating satisfied the minimum shielding criteria. In conclusion, it is considered that 100 µm of Iron-Aluminum alloy metal spraying coat contains high efficiency in the HEMP shielding.

Multidimensional Analysis of Unstructured Data and Trends in Architectural Review Opinions of Small and Medium-Sized Apartment Projects (다차원 분석방법을 활용한 중소규모 공동주택 건축심의 의견의 경향과 비정형 데이터로서의 특성분석)

  • Kim, Jinhee;Hwang, Taeeon;Kim, Jae-Sik;Huh, Youngki
    • Korean Journal of Construction Engineering and Management
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    • v.24 no.6
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    • pp.74-80
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    • 2023
  • This study examines the characteristics of architectural review opinions as unstructured data, focusing on the most challenging risk for developers of small and medium-sized apartment projects in response to the increasing number of single-person households in Korea. Using multidimensional analysis methods, the study analyzes the review opinions of 25 projects in B City. Correspondence analysis and MDS (Multidimensional Scale) analysis show that, consistent with prior research, the keywords related to 'structure' and 'planning' dominate architectural review opinions in B City. While the MDS model's stress is very poor at 34.4%, correspondence analysis reveals that this is due to the characteristics of unstructured data in architectural reviews. In addition, the non-structured data analyzed in this study, such as architectural review opinions, exhibited a probability distribution with low kurtosis and high skewness, as they involved various combinations and occurrences of data depending on the discretion of the review committee members and the specific formats of different local governments. This often led to the emergence of keywords that differed significantly from commonly mentioned terms. Although the study has some limitations, it provides a foundation for future detailed analysis by identifying the characteristics of architectural review opinions as unstructured data.

Edible mushroom (Pleurotus cornucopiae) extract vs. glibenclamide on alloxan induced diabetes: sub-acute in vivo study of Nrf2 expression and renal toxicity

  • Chinedu Godwin Uzomba;Uchenna Kenneth Ezemagu;Mary-Sonia Ofoegbu;Njoku Lydia;Essien Goodness;Chinedum Emelike;Uchewa Obinna;Alo Joseph Nwafor;Ejikeme Felix Mbajiorgu
    • Anatomy and Cell Biology
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    • v.57 no.3
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    • pp.446-458
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    • 2024
  • The study aims to compare the action of Pleurotus cornucopiae and glibenclamide on alloxan-induced diabetes and ascertain how an aqueous extract of the edible mushroom regulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), oxidative stress biomarkers and renal toxicity in a diabetic male Wistar rat model. Twenty-five adult male Wistar rats were randomly grouped into five groups with five rats per. Group 1 and those in the treatment groups received normal feed and water ad libitum. Group 2 received intraperitoneal administration of alloxan monohydrate (150 mg/kg body weight). Group 3 received alloxan monohydrate and glibenclamide (5 mg/kg body weight bwt), group 4 received alloxan monohydrate plus the extract (250 mg/kg bwt) and group 5 received alloxan monohydrate plus the extract (500 mg/kg bwt). The administration of glibenclamide plus the extract was oral for 14 days. Glibenclamide and the extract lowered blood glucose level, catalase, and glutathione peroxidase activities, increased the superoxide dismutase (SOD) activity in rats with alloxan induced diabetes. The extract at 500 mg/kg bwt reduced the plasma urea and sodium concentration in the treated rats. The extract and glibenclamide could detoxify alloxan and restore its induced renal degeneration and glomeruli atrophy, intra renal hemorrhage and inflammation and oxidative biomarkers through activation of Nrf2 expression. The drug glibenclamide and P. cornucopiae have appreciable hypoglycemic activity and potential to restore the normal renal architecture in the rats, hence they offer similar curative effects. Additionally, the extract at 500 mg/kg bwt activated SOD and Nrf2 expression more than glibenclamide in rats with alloxan-induced diabetes.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Correlation of Proliferating Cell Nuclear Antigen (PCNA) Expression and S-phase Fraction, Survival Rate in Primary Non-Small Cell Lung Cancer (원발성 비소세포 폐암에서 PCNA의 발현정도와 암세포의 분열능 및 생존률과의 관계)

  • Yang, Sei-Hoon;Kim, Hak-Ryul;Gu, Ki-Seon;Jung, Byung-Hak;Jeong, Eun-Taik
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.4
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    • pp.756-765
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    • 1997
  • Background : To study the prognosis of patients with lung cancer, many investigators have reported the methods to detect cell proliferation in tissues including PCNA, thymidine autoradiography, flow cytometry and Ki-67. PCNA, also known as cyclin, is a cell related nuclear protein with 36KD intranuclear polypeptide that is maximally elevated in S phase of proliferating cells. In this study, PCNA was identified by paraffin-embedding tissue using immunohistochemistry which has an advantage of simplicity and maintenance of tissue architecture. The variation of PCNA expression is known to be related with proliferating fraction, histologic type, anatomic(TNM) stage, degree of cell differentiation, S-phase fraction and survival rate. We analyzed the correlation between PCNA expression and S-phase fraction, survival. Method : To investigate expression of PCNA in primary lung cancer, we used immunohistochemical stain to paraffin-embedded sections of 57 resected primary non-small cell lung cancer specimen and the results were analyzed according to the cell type, cell differentiation, TNM stage, S-phase fraction and survival. Results : PCNA expression was divided into five group according to degree of staging(-, +, ++, +++, ++++). Squamous cell type showed high positivity than in adenocarcinoma. Nonsignificant difference related to TNM stage was noticed. Nonsignificant difference related to degree of cell differentiation was noticed. S-phase fraction was increased with advance of PCNA positivity, but it could not reach the statistic significance. The 2 year survival rate and median survival time were -50% 13 months, +75% 41.3 months, ++73% 33.6 months, +++67% 29.0 months, ++++25% 9 months with statistic significance (P<0.05, Kaplan-Meier, generalized Wilcox). Conclusion : From this study, PCNA expression was high positive in squamous cell cancer. And, there was no relationship between PCNA positivity and TNM stage, cellular differentiation or S-phase fraction. But, the patients with high positive PCNA staining showed poor survival rate than the patients with lower positive PCNA staining (p<0.05). It was concluded that PCNA immunostaining is a simple and useful method for survival prediction in paraffin embedded tissue of non-small cell lung cancer.

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Predictive Factors for Prognosis of Neonatal Intrahepatic Cholestasis : Non-Familial, Non-Metabolic, Non-Syndromic Cholestasis (신생아 간내 담즙 정체증의 예후 인자: 비가족성, 비대사성, 비증후성 담즙 정체증)

  • Kim, Hyung Suck;Lee, Chang Hoon;Kim, In Ju;Park, Jae Hong
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.7 no.2
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    • pp.208-214
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    • 2004
  • Purpose: The prognosis of neonates with cholestasis is not clear. Some factors, such as high peak bilirubin levels and liver histologic findings have been claimed to affect the prognosis adversely. Our study aims to define which factors influence the prognosis of neonatal intrahepatic cholestasis. Methods: Retrospective reviews of the medical records were performed in 32 cases with neonatal intrahepatic cholestasis, who were admitted to Department of Pediatrics, Pusan National University Hospital from July 1995 to July 2002. Neonates were classified into 2 groups according to the duration of elevated serum alanine aminotransferase (ALT) levels more or less than 6 months. The data, such as biochemical, histopathologic and radiologic findings, were compared in both groups. Biochemical data included mean peak level of serum ALT, total bilirubin, direct bilirubin, and alkaline phosphatase. Histologic parameters related to lobular architecture, fibrosis, inflammatory infiltration and degenerative features of hepatocytes were arbitrary estimated on a scale of 1 to 3. Results: There were 19 males and 13 females, whose mean age was 48 days (14~77 days). The peak serum ALT levels were higher in the poor outcome group. Ductular proliferation and portoportal bridging were more severe in the poor outcome group. But the degree of multinucleated hepatocytes, hepatocellular swelling and canalicular plug did not appear to be significantly related to the long-term outcome. The DISIDA scintigraphy by visualization time of gall bladder and intestine was not useful in predicting outcome of neonatal intrahepatic cholestasis. Conclusion: Neonates who have intrahepatic cholestasis with high serum ALT levels, severe ductular proliferation and portoportal bridging in the liver biopsy specimen should be carefully followed up because they may have a poor prognosis.

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