• Computers and Concrete
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• v.16 no.6
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• pp.865-880
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• 2015

Standard test method for bulk electrical conductivity (ASTM C1760) provides a rapid indication of the concrete's resistance to the penetration of chloride ions by diffusion. In this paper a new approach for assessing the bulk electrical conductivity of saturated specimens of hardened concrete is presented. The test involves saturating concrete specimens with a 5 M NaCl solution before measuring the conductivity of the samples. By saturating specimens with a highly conductive solution, they showed virtually the same pore solution conductivity. Different concrete samples yield different conductivity primarily due to differences in their pore structure. The feasibility of the method has been demonstrated by testing different concrete mixtures consisting ordinary and blended cement of silica fume (SF) and calcined perlite powder (CPP). Two standard test methods of RCPT (ASTM C1202) and Bulk Conductivity (ASTM C1760) were also applied to all of the samples. The results show that for concretes containing SF and CPP, the proposed method is less sensitive towards the variations in the pore solution conductivity in comparison with RCPT and Bulk Conductivity tests. It seems that this method is suitable for the assessment of the performance and durability of different concretes containing supplementary cementitious materials.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.205-211
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• 2023

Hydrogen gas is light and diffuses very quickly. Therefore, when a leakage accident occurs, the damage is great, so a technology that can quickly measure the leakage in the air at a long distance is needed. In order to develop hydrogen gas leaked in the atmosphere in a non-contact manner, an experiment was performed to measure hydrogen gas using a lidar technology using the Raman effect. Hydrogen Raman signals were detected using a UV LED light source, which is a Raman light source, and a spectrometer in the ultraviolet region including an optical filter in the 400-430 nm band. To develop this, a Raman lidar optical structure was designed to measure the hydrogen Raman signal at a certain distance, and the hydrogen Raman spectrum was confirmed using a standard gas to evaluate the performance of this optical structure. The linearity was found to be 0.99 using hydrogen standard gas (10, 50, 100, 500, 1,000 ppm). Accordingly, a Raman lidar capable of measuring hydrogen gas rapidly diffusing in the air in an open state was developed to improve the limitations of existing hydrogen sensors.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1148-1153
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• 2006

Signal measuring system to analyze ion concentrations in biofilm was constructed with ion selective microeleclrode and electrometer. In order to evaluate the performance and applicability of signal measuring system, the following characteristics, such as slope of calibration curve, detection limit, variation of response according to the time, and potentiometric selectivity coefficient, were investigated. The slope of calibration curve showed high degree of association for primary ion concentration. The response of the system was log-linear in standard solution down to $10{\mu}M$ and signal measuring system was not sensitive for interfering ions. In comparison with commercial electrometer, the fabricated electrometer system had similar tendencies for the slope of calibration curve, detection limit, and response time. Therefore the signal measuring system could be used to investigate ion profiles in biofilm as a cost effective and reliable measuring system.

• Clean Technology
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• v.23 no.2
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• pp.181-187
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• 2017

The perfluorocompounds (PFCs) emitted from the semiconductor and display manufacture is treated by abatement systems which use various technologies, such as combustion, thermal, plasma, catalyst. However, it is required that the system should overcome their drawbacks with excess energy consumption and low removal efficiency. The new technology using combination of pressure swing adsorption and excess enthalpy combustion for the reduction of PFCs emissions were developed and analyzed its characteristics. PFCs concentration ratio and PFCs loss factor were calculated from measuring concentration of PFCs at the calculated by comparing concentration of PFCs at the combustor's inlet and outlet. There were performance evaluations with various gas flow for comparing energy consumption and removal efficiency with existing equipments. The concentration ratio and the loss factor of PFCs were 1.65, 8.2%, respectively, when the total gas flow of the pressure swing absorption (PSA) inlet was 204 liter per minute (LPM) and $CF_4$ concentration was 1412 ppm. In comparison with existing system at constant condition, $CF_4$ removal efficiency for a porous media combustion (PMC) showed the improvement more than 16% and the consumed energy was also reduced up to approximately 41%. Then, the total gas flow introduced into PMC and $CF_4$ concentration were 91-LPM and 2335 ppm, respectively, and the destruction and removal efficiency of $CF_4$ was about 96% at 19-LPM $CH_4$, and 40-LPM $O_2$.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.4 s.152
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• pp.542-553
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• 2006

The purpose of this study were to analyse of craniofacial shape by 3D and to develope of head models for Korean adults with gender and age groups. The 3D measurement technique adapted in this study was a novel approach compared that the same technique has been commonly used in measuring human bodies. The data and the model of head analysis can be used as a basic reference in developing various head related items such as hat, helmet, gas mask, ear phone, and etc. In this study, heads of 836 Korean adults were measured in 3D, analyzed by statistical methods, and modelized in 3D by gender and age groups. From the basic statistical data analysis, vertex-tragion and the length between the pupils were the longest in their twenties for both men and women, and grew shorter in elderly groups. In all categories, a significant difference appeared between men and women in their 20's, but the differences were less noticeable in elderly groups. Compared to the one size standard head model of the Korea Occupational Safety and Health Agency, the above three-dimensional standard head model would provide a more through fit because gender and age groups were sub-divided and analyzed in 3D.

• Molecules and Cells
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• v.45 no.2
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• pp.76-83
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• 2022

Neurons-on-a-Chip technology has been developed to provide diverse in vitro neuro-tools to study neuritogenesis, synaptogensis, axon guidance, and network dynamics. The two core enabling technologies are soft-lithography and microelectrode array technology. Soft lithography technology made it possible to fabricate microstamps and microfluidic channel devices with a simple replica molding method in a biological laboratory and innovatively reduced the turn-around time from assay design to chip fabrication, facilitating various experimental designs. To control nerve cell behaviors at the single cell level via chemical cues, surface biofunctionalization methods and micropatterning techniques were developed. Microelectrode chip technology, which provides a functional readout by measuring the electrophysiological signals from individual neurons, has become a popular platform to investigate neural information processing in networks. Due to these key advances, it is possible to study the relationship between the network structure and functions, and they have opened a new era of neurobiology and will become standard tools in the near future.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.1-6
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• 2004

Measurements of circular motion accuracy of NC lathe have achieved with ball bar systems proposed by Bryan, but the ball bar systems have ifluenced on the measuring data by way of the accuracy of the balls and the contacts of balls and bar seats. Therefore in this study, error data during of circular motion of ATC(Automatic Tool Changer) of NC lathe will be acquired by reading zx plane coordinates using two optical linear scales. Two optical linear scales of measuring unit are fixed on z-x plane of NC lathe, and the moving part is fixed to ATC and then is made to receive data of coordinates of the ATC at constant time intervals using tick pulses comming out from computer. And then, error data files of radial direction of circular motion are calculated with the data read, and the aspect of circular motion are modeled to plots, and are analysed by means of statistical treatments of circularity, means, standard deviations etc.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.864-873
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• 2013

In developing countries, biogas energy production is seen as a technology that can provide clean energy in poor regions and reduce pollution caused by animal manure. Laboratories in these countries have little access to advanced gas measuring equipment, which may limit research aimed at improving local adapted biogas production. They may also be unable to produce valid estimates of an international standard that can be used for articles published in international peer-reviewed science journals. This study tested and validated methods for measuring total biogas and methane ($CH_4$) production using batch fermentation and for characterizing the biomass. The biochemical methane potential (BMP) ($CH_4$ NL $kg^{-1}$ VS) of pig manure, cow manure and cellulose determined with the Moller and VDI methods was not significantly different in this test (p>0.05). The biodegradability using a ratio of BMP and theoretical BMP (TBMP) was slightly higher using the Hansen method, but differences were not significant. Degradation rate assessed by methane formation rate showed wide variation within the batch method tested. The first-order kinetics constant k for the cumulative methane production curve was highest when two animal manures were fermented using the VDI 4630 method, indicating that this method was able to reach steady conditions in a shorter time, reducing fermentation duration. In precision tests, the repeatability of the relative standard deviation (RSDr) for all batch methods was very low (4.8 to 8.1%), while the reproducibility of the relative standard deviation (RSDR) varied widely, from 7.3 to 19.8%. In determination of biomethane concentration, the values obtained using the liquid replacement method (LRM) were comparable to those obtained using gas chromatography (GC). This indicates that the LRM method could be used to determine biomethane concentration in biogas in laboratories with limited access to GC.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.62
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• pp.33-48
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• 2001

International transfer of technology is not a simple mechanical progress obtaining technology from overseas, but a sysmetic progress for advancing ability of domestic research development through technology, men of talent, advanced management and its experience. In this progress, it is a important yardstick measuring a country's standard of technology & productivity and self-reliance of industrialization whether countries have introduced some technologies or settled them somehow or not. Through these views, this paper is dealing in major features on each stage in connection with economic system's change, strategy of economic development and industrialization of China regarding transfer technology in China extended during five decades after war.

• Journal of Sensor Science and Technology
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• v.4 no.2
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• pp.3-6
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• 1995

Type K thermocouples having multi-junction for measuring the temperature gradient of the furnace were fabricated. The obtained results on the temperature gradient of the electric furnace maintained at $800^{\circ}C$ were consistent with those for the reference grade type S thermocouple, which was carefully calibrated, within the permitted error limit of the type K thermocouple. It was suggested that noble metal multi-junction thermocouples be suitable for more accurate temperature gradient measurements.