• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.60-66
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• 2007

The first Korean cold room facility for ice mechanics experiments was assembled in 2004. Since then, the $4m{\times}6m$ cold room facility has been used, extensively under various environmental and loading conditions. After reviewing published references on cold room testing methods and also by trial and error, the standard procedures for testing and preparing laboratory ice material were established for the measurement of basic ice properties. In this paper, laboratory experimental techniques with the cold room facility and standard procedures established for ice material properties are introduced. Test specimens include laboratory-grown fresh water ice and frozen soils. Tests are carried out for unconfined compressive strength. Preparation and dimension of the specimen are the most important issues arising in cold room tests. The details of specimen preparation, testing procedure and strength test results are also discussed.

• Journal of Korea Foundry Society
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• v.35 no.6
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• pp.170-177
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• 2015

Segregation during solidification and homogenization during thermal exposure in GTD 111 were investigated. The microstructures of as-cast, standard heat-treated, and thermally exposed specimens were observed by SEM. A compositional analysis of each specimen was conducted by EDS. The dendrite core was enriched in W and Co, though lower levels of Ti and Ta were observed. An unexpected phase, in this case like the ${\eta}$ phase, was observed due to segregation near the ${\gamma}-{\gamma}^{\prime}$ eutectic in the standard heat-treated specimen. Segregation also induced microstructural evolution near the ${\gamma}-{\gamma}^{\prime}$ eutectic during the standard heat treatment. A quantitative analysis and microstructural observations showed that the thermal exposure at a high temperature enhanced the chemical homogeneity of the alloy.

• Geomechanics and Engineering
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• v.37 no.2
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• pp.109-122
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• 2024

Standard triaxial cells are commonly used to measure the mechanical behavior of saturated soils. However, this type of standard system is difficult to use for unsaturated soil specimens since it cannot measure the changes in the pore-air volume and pressure. This paper proposes to extend the measurement possibilities of the standard triaxial testing device in a simple way and to adapt it to partially saturated soils. The system is supplied by two hygrometers installed at each end of the cylindrical unsaturated specimen to measure local relative humidity, which allows the derivation of suction. The volumetric strain of the specimen is calculated by analyzing digital photos captured from the outside of the transparent cell wall. Specimens made of kaolin clay, having different hydraulic properties, were tested to verify the reliability of the measurements, and thus, the relevance of the proposed techniques to study the mechanical behavior of unsaturated soils.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.781-784
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• 2008

Recently as application of high-strength concrete on concrete structures has been on the rise, use of non-standard specimen is increasing. Therefore, this study investigated the effect of specimen's size effect, ratio of height/diameter and curing conditions on concrete compressive strength. Results of experiments showed that as size of specimen increased as much as 1 mm, standard design compressive strength of 24MPa fell as much as0.15MPa 40MPa fell as much as 0.1MPa 80MPa fell as much as 0.3MPa, and it indicates that as the level of strength is intensified, the decrement of compressive strength increases. As ratio of height/diameter increased as much as 1.0, compressive strength of 24MPa fell as much as 2.9MPa 40MPa fell as much as 3.7MPa 80MPa fell as much as 9.8MPa, and it means that as strength of concrete is higher, influence of ratio of height/diameter becomes bigger.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.87-92
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• 2014

The Notched Ring Test(NRT) has proven to be very useful in determining the slow crack growth behavior of polyethylene pressure pipes. In particular, the test is simple and an order of magnitude shorter in experimental times as compared to the currently used Notched Pipe Test(NPT), which makes this method attractive for use as the accelerated slow crack growth test. In addition, since the NRT specimen is taken directly from the pipe, having maintained the cross-section, processing induced artifacts that would affect the slow crack growth behavior are not altered. This makes the direct comparison to the slow crack growth specimen in pipe from more meaningful. In this study, for comparison with other available slow crack growth methods, including the NPT, the stress intensity factor equation for NRT specimen was developed and demonstrated of its accuracy within 3% of that obtained from the finite element analysis. The equation was derived using a flexure formula of curved beam bending along with numerically determined geometric factors. The accuracy of the equation was successfully tested on 63, 110, 140, 160, 250, and 400 mm nominal pipe diameters, with crack depth ranging from 15 % to 45 % of the pipe wall thickness, and for standard dimensional ratio(SDR) of 9, 11, and 13.6. Using this equation the slow crack results from 110SDR11 NRT specimen were compared to that from the NPT specimen, which demonstrated that the NRT specimen was equivalent to the NPT specimen in creating the slow crack, however in much shorter experimental times.

• Journal of Environmental Impact Assessment
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• v.17 no.4
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• pp.225-233
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• 2008

An Environmental Specimen Bank (ESB) is an archive for samples that can be used to document and assess the quality of the environment in which we live. An ESB program looks at changes in the concentration of human and environmental specimens over long periods of time through retrospective analysis of archived samples of a particular area collected at regular intervals. The idea of ESB was first proposed by German and American scientists in the early 1970s and has been established since 1979 in Germany, USA, and Japan. Korea plans to establish a National Environmental Specimen Bank (NESB) in 2010. The NESB will be able to assess and improve the quality of analytical measurements as well as to compare the past and current environmental quality as a time capsule. The concept and design for the NESB facility was developed and its Standard Operation Procedures (SOPs) are being developed based on an evaluation of ESBs and SOPs of Germany, USA, and Japan. Environmental specimens proposed for banking are based on typical representatives of every level of the food chain from each type of ecosystem that are widely distributed thus enabling comparisons between different sampling areas. Through retrospective analysis of environmental specimens, the NESB will improve the reliability of environmental monitoring, ecological risk assessment, and health impact assessment.

• Journal of Welding and Joining
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• v.26 no.2
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• pp.43-49
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• 2008

Fatigue cracks due to thermal stratification or corrosion in pipelines of nuclear power plants can cause serious problems on reactor cooling system. Therefore, the development of an integrated technology including fabrication of standard specimens and their practical usage is needed to enhance the reliability of nondestructive testing. The test material was austenitic STS 304, which is used as pipelines in the Reactor Coolant System of a nuclear power plants. The best condition for fabrication of thermal fatigue cracks at the notch plate was selected using the thermal stress analysis of ANSYS. The specimen was installed from the tensile tester and underwent continuos tension loads of 51,000N. Then, after the specimen was heated to $450^{\circ}C$ for 1 minute using HF induction heater, it was cooled to $20^{\circ}C$ in 1 minute using a mixture of dry ice and water. The initial crack was generated at 17,000 cycles, 560 hours later (1cycle/2min.) and the depth of the thermal fatigue crack reached about 40% of the thickness of the specimen at 22,000 cycles. As a results of optical microscope and SEM analysis, it is confirmed that fabricated thermal fatigue cracks have the same characteristics as real fatigue cracks in nuclear power plants. The crack shape and size were identified.

• Journal of Environmental Impact Assessment
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• v.21 no.2
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• pp.327-338
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• 2012

Environmental specimen banks provide the baselines for the scientists and decision makers to do research using the past and present specimens to expect the possible contaminant implications of the future. Many chemicals that are considered harmless now but not found may be found and pose threats in the future. Collected specimens of animals and plants should be conserved without contamination for future analysis. To ensure the availability of samples for the retrospective analysis, the establishment and maintenance of specimen banks in the developing and developed nations has become absolutely necessary. National Environmental Specimen Bank (NESB) established at National Institute of Environmental Research (NIER) in 2009. For the application of NESB, several activities such as standard operating procedures (SOPs) development have been prepared. This study applied the guidelines for sampling and sample treatment of five environmental specimens which had been prepared from 2007 to 2009. The target species were shoots of red pine and Korean pine, leaves of Mongolian oak, eggs of domestic pigeon and muscles and livers of common carp. The NESB will enhance the quality of environmental assessment and environmental monitoring based on real time and retrospective analysis.

• Land and Housing Review
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• v.6 no.1
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• pp.11-19
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• 2015

This paper presents experimental results on detailing of boundary element transverse reinforcement, proposed to alleviate placement detailing of special shear wall experiencing difficulty in construction at the sites due to recently reinforced seismic regulations, according to the type and placement interval of transverse reinforcement. As a result of experiment, crack and destruction aspects of SSWR series specimen that employed the proposed detailing of transverse reinforcement showed similar trend as SSW series specimen that used closed hoop. Predicted maximum strength values were exceeded. Also as a result of comparing energy dissipation ability, SSWR2 specimen that follows alleviated placement detailing was found to have similar seismic performance as special shear wall SSW2 specimen based on the existing design standard. As it satisfies the deformation angle condition of 1.5% provided in the design standard, SSWR2 can be used as the main lateral force resistance element in structures.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.186-199
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• 2002

This is a brief review and discussion for present status and prospects of quality evaluation in medicinal plants as oriental medicine materials (OMM). Quality in medicinal plants could be defined as the combination of origin, external appearance, effectiveness and safety, and be evaluated by plant taxonomic, morphological, physiochemical and biological methods. For high-quality improvement and standardization of OMM, medicinal plants should be produced through using proper species or good variety and standard cultivation method in suitable cultivation area. Standardizing of quality means to meet with minimum qualifying criteria of OMM in the market while improving of quality to be over standard quality of medicinal piano in production. For making new high quality and standardized products, we need to keep standard field plants, standard OMM, standard plant specimen, and standard compounds. Researchers and administration have to study and propose the quality factors and their evaluating techniques and criteria, so high-quality and standardized produce of medicinal plane could be produced and distributed under the control of the relevant regulations, and would be contributed to increasing of national health.