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        검색결과 37

        1.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The air dilution olfactory method to measure complex odors needs to store and carry odor samples from the field sampling until the analysis in laboratories. Until the analysis of sample in the laboratory, odor dilution factor (odor sensitivity) in the sample bag may decrease over time depending on the characteristics of each odor substances. This is one of the limitation for the air dilution olfactory method. Thus, the air dilution device enable to measure without loss in complex odors of samples. Recently, many studies on the performance test of on-site air dilution devices, i.e., field olfactometer, has been conducted to figure out the feasibility of the field olfactometers. In this study, seven odor samples were collected from five odor emission source sites. And comparative analysis with the air dilution olfactory method was carried out to assess the field applicability of the olfactometer. As results, the performance of the field olfactometer used in this study is regared as the affordable method. The dilution factors from between two methods showed the similar values, indicating low values of standard deviations. In order to ensure the accuracy and precision of measurement data using the field olfactometer, methodology minimized variables (that may affect measurement) needs to establish.
        4,000원
        2.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to present a practical application method for measuring the setting time of concrete in the field, considering different concrete blending and curing environments. METHODS : In the experimental environment of the concrete setting experiment, a mold was made in the laboratory, and the curing temperature was performed at laboratory room temperature (20-25 ℃), heater (30 ℃), and dryer (40 ℃). In the field, the experimental method was performed in summer and autumn, setting experiments on penetration resistance, ultrasonic pulse velocity, and semi-calorimeter. RESULTS : The result of the concrete setting time experiment was that the early setting time was achieved in the combination of filash and slag when the concrete was mixed, and the setting time in the curing environment was the same as the early setting time in the field. The setting time measurement method shows the correlation of the high crystal coefficient at UPV with 0.99 based on PR and the good ratio of 92 % to 107 % on average. In addition, the semi-calorimeter shows a good crystal coefficient of 0.96 to 0.99 and a good setting time of 88 % to 101 % on average. CONCLUSIONS : The analysis of the setting time of the concrete shows that the curing temperature is more affected than the mixture, and it is considered that the UPV test, which evaluates the reliability of the degree of purification, is easy to sampie among the three methods.
        4,000원
        4.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the advancement of industrialization, modern industry had sophisticated technology, and manufacturers also demanded high-precision measurement accuracy. Improving the quality level by increasing the reliability of measurement results as well as accurate measurement is a key issue to increase the competitiveness of today's manufacturing industry. In general, measurement results depend on tolerances in the industrial field, and it may be difficult to guarantee the reliability of the data in the case of an industry that deals with precision parts. Currently, measurement uncertainty is mainly applied to the calibration and test fields of instruments. This study is aim to apply measurement uncertainty as a way to improve the accurate analysis and reliability of measurement results in the industrial field. For this, precision parts connected by shaft and hole were selected among geometric elements, and roundness and cylindricity were measured using a roundness measuring instrument and CMM. And, taking into account the environment in which these measurements were made, factors affecting the measurement results were derived, and a mathematical model was established to calculate the measurement uncertainty. Applying uncertainty in the field in this way is expected to improve the level of quality and accurate analysis of measurement results.
        4,000원
        5.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to analyze the crack and vertical behaviors of a continuously reinforced concrete pavement (CRCP) under three different steel ratios (0.6%, 0.7%, and 0.8%) using field measurement data acquired from isolated concrete slabs with transverse cracks. METHODS : Using an LVDT and a crack gauge, CRCP behavior data are acquired by segmenting a concrete slab into multiple sections based on the similarity in the longitudinal steel ratio of each section. To examine the vertical behavior of CRCP based on longitudinal steel ratios, three field experiments are conducted in February, May, and September three years after project completion. The minimum and maximum ambient temperature data for each section are acquired during the experiments. Using the data acquired, the vertical and crack behaviors of CRCP with 0.6% of longitudinal steel ratios are analyzed. In addition, the effect of the steel ratio on the vertical behavior as well as seasonal vertical behaviors are examined. RESULTS : Analysis of the vertical behavior of concrete slabs with a 0.6% steel ratio shows that the minimum vertical displacement occurred at the center of the slab, whereas a significant vertical displacement is detected on the edges of the slab. Based on examining vertical displacements formed along the direction of transverse cracks, it is observed that the vertical behavior is prominent around the shoulders, whereas similar vertical behaviors are observed at the center and joints of the slab. Furthermore, it is discovered that the minimum crack occurred at the center of the transverse cracks, whereas the maximum crack occurred on the shoulders and joints. Furthermore, it appears that the daily displacements of the vertical behavior at the center of the slab constitute approximately one-half of the daily displacements on the joints. Based on the results of vertical behavior as a function of the longitudinal steel ratios, it is discovered that steel ratios of 0.7% and 0.8% yield the most prominent vertical behaviors around the edge of the shoulder in the winter, spring, and fall seasons. The seasonal deviations of the vertical behaviors based on the measuring positions of the longitudinal steel ratios appear less significant at the center of the slab than those on the shoulder. In particular, for the slab with a steel ratio of 0.8%, subtle vertical behaviors are observed at the center. It is discovered that the seasonal deviation of the vertical behavior measurements varying by the measuring locations of the steel ratios appears less significant at the center of the slab than at the shoulder, and that it decreases with the steel ratio. CONCLUSIONS : CRCP generates cracks on the slab; however, they are managed by rebars in the CRCP. This study reveals that the major vertical and crack behaviors of CRCP occur around the shoulders than at the center of the CRCP slab. Therefore, new methods for managing cracks on the CRCP shoulder should be developed to improve the performance of CRCP. It is hoped that the results presented herein will be useful for the advanced analysis of CRCP behaviors.
        4,000원
        6.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구에서는 RC 연결구조를 갖는 교량의 장기거동을 확인하기 위한 현장조사를 수행한다. 우선, 온도계 센서, 변위 센서, 변형률게이지를 설치하고, 3년 6개월동안 현장계측을 수행하였다. 현장계측 결과, 수축변위는 동일한 온도변화에서 흉벽에 작용하는 뒷채움제의 토압의 영향으로 인해 신장변위보다 크게 나타났다. 또한, 상부구조 변위는 하부구조의 강성의 영향으로 인해 하부구조보다 크게 나타났다. 변형률 측정 결과, 보강재의 응력은 온도변화에 따른 압축응력과 인장응력의 반복이 원인인 것으로 나타났다.
        4,000원
        7.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study primarily aims to develop and evaluate a Smart Station - a novel underground pipeline measure system - to overcome the challenges of conventional surveying methods. METHODS : This study built two prototypes of the Smart Station. By reflecting issues revealed through the field tests of the first prototype, this study produced the second Smart Station prototype. The organization of the hardware units in the second prototype was reconfigured to maximize its usability for operators in the field. Furthermore, by developing the ‘Digital Twin X’, an integrated Smart Station management software suite, the second prototype was capable of 1) producing a digital workbook for field operators, 2) managing underground pipeline information, and 3) displaying 3-dimensional maps in and around an underground pipeline. The applicability of the second prototype was examined through three field tests conducted in one open space location, where no urban valley effects were expected, and two locations in a downtown area, with urban valley effects. Given the actual field installation of underground pipelines, this study collected data via both conventional surveying methods and the Smart Station to evaluate the performance of the Smart Station. Analyzing the field data, this study examined the data collection time and position accuracy of an underground pipeline measured by the Smart Station. RESULTS : The field test results revealed that both the conventional surveying method and the Smart Station produced similar performances in data collection time and measurement accuracy in the open space test location. However, in the case of downtown locations affected by urban valley effects, the Smart Station achieved 100 % measurement accuracy while the conventional surveying method achieved 93 % accuracy. It was also observed during the field test that no data were collected due to the constraints of the work schedule and various field conditions (e.g., weather and/or traffic congestion). The data collection times at the open space locations were 10 s for both the conventional surveying method and the Smart Station. However, the data collection times at the downtown locations appeared to be 10 s and 360 s by the Smart Station and the conventional surveying methods, respectively, thereby proving that the Smart Station outperforms the conventional method in its measurement efficiency. CONCLUSIONS : It is envisioned that the Smart Station produces higher work efficiency for field operators as it enables them to collect high accuracy data in a timely and quick manner and not only build a database for the collected data but also vividly visualize it in the field. In the future, it is necessary to conduct additional field tests under various conditions for the in-depth investigation of a Smart Station. In addition, it is expected that the Smart Station will be enhanced by coupling augmented reality (AR) technologies.
        4,000원
        8.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        농업용 노외작업 기계는 작업속도가 변이하므로 경운 시비 방제 파종 작업등에서 주행속도를 정확하게 측정할 필요가 있다. 도플러 레이더는 포장에서 속도측정의 신뢰성이 있어 견인효율 또는 변량제어 연구 등에서 사용될 수 있을 것으로 판단된다. 따라서 본 연구에서는 도플러 레이더 속도계를 이용하여 주행속도를 측정할 때 콘크리트 견고지면에서 보정된 기준 변환계수를 포장실험에서도 적용이 가능한지에 대한 엄격한 통계적 검토와 검증을 수행하였다. 견고지면에서 얻은 기준 변환계수를 비교군으로 포장실험의 결과를 검증하기 위하여 Proc GLM을 사용하였다. 완전모델 의 분산분석 결과에서 유의하지 않은 교호항을 제거한 주 변수모델에 대하여도 유의하지 않았다. 사후분석에서 보수적이고 엄격한 Scheffe 방법으로 민감한 계수를 검정하였고 또한 유의하지 않았다. 기준 변환계수를 비교군으로 하여 대비처리(contrast) 하였고 유의하지 않았다. 견고지면에서 평가한 기준 변환계수(a0=0.0396)와 기준절편(y0=-0.0235)을 바탕으로 평가한 변환계수(a)의 절대오차(Erra)는 –0.415×10-3 이었고, 퍼센트 오차는 –1.18% 였다. 따라서 기준 변환계수는 포장작업의 주행속도의 환산계수로 사용되어도 측정치에 심각한 오차를 초래하지 않을 것이다.
        4,600원
        9.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to evaluate the odor occurrence of offensive leather odor in a district in Gyeonggi-do, where Jeil industrial complex is located, and its residential district, by using olfactory field frequency measurement (Gird Method). In addition, we measured the composite odor. The target points were 9 spots in Jeil industrial complex and 12 spots in the residential district, and we conducted the measurements 13 times each spot. As a result, odor occurrence in descending order was investigated as follows, leather industry > drug industry > food industry. Moreover, odor exposure of the industrial complex exceeded the industrial zone standard of 0.15 (=German odor standard) in all 9 spots (average 0.78). In addition, odor exposure of the residential district exceeded the residential zone standard of 0.10 (=German odor standard) in 12 spots (average 0.78). All the composite odors were below 20 (industrial zone standard). However, as the odor intensity of the sampling site and the lab analysis data showed a large deviation, we found that much supplementation is needed of the odor analysis techniques in the equipment measurement methods.
        4,000원
        10.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we conducted a survey on odor characteristics of single odor and collective odor facilities using the German olfactory odor method and carried out the odor frequency modeling. The influence of the odor from a sewage treatment plant, which is a single discharge facility, was strong in the eastern and northern parts of the plant and appeared to be in good agreement with the areas where the odor complaints were frequent. The German olfactory method reflects the odor complaints and odor occurrence characteristics of the receptors as compared with the domestic odor measurement method. The influence of the odor from the odor control area, which is a collecting and discharging facility, showed a tendency in which the sum of the odor occurrence frequency increased with the proximity of the odor discharge facility to the dense industrial complex. Furthermore, it was judged that it is not easy to extract the odor frequency results for individual facilities because the survey subject is the group discharge facility area. Therefore, it will be necessary to introduce a method to manage odor in the future. In this study, the measurement of odor frequency using the German olfactory odor method is partially applied to some odor sources. Appropriately, it is not applicable to various emission sources. However, the odor measurement method based on odor occurrence frequency and odor sensory can be used for investigation of the actual condition, permits of odor discharge facilities and the environmental review.
        4,300원
        11.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Despite increasing public concern following mass media coverage regarding the risk of radon to human health and the need to control it, there remains a lack of infrastructure for measuring and mitigating radon. Against this backdrop, this paper is part of an effort to formulate an environment-management framework that can help resolve environmental issues relating to radon, ease fears regarding the associated risks, and provide radon-specific quality services. This study aimed to suggest locally applicable measures for training experts specializing in the fields of measuring and mitigating radon mainly based on US cases in which radon measurement and mitigation certification programs have been systematically run and supervised. Given the lack of both awareness on radon and experts in Korean circumstances, it is necessary to come up with a scheme to develop a radon-specific education program and a framework for expert accreditation. Thus, as groundwork for their introduction considering local circumstances, top-down measures led by the relevant department of government-led organizations, which will act as the control tower, should first be implemented to best utilize the insufficient human resources in this area. In addition, more systematic and detailed educational programs and an expert certification system need to be developed in accordance with the established foundations, and to support their consistent operation, a relevant administrative system should be constructed.
        4,000원
        14.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Local Nusselt number and temperature field distribution within the compound duct with gap have been measured. Measurement of air and wall temperature span a range of gap width from 2mm to 6mm. Also, the Reynolds number is variated from 20,000 to 40,0000. In order to observe the correlations between gap width and turbulent heat transfer, the present measurement has tried to verify the enhancement effect of heat transfer when a gap exists within the compound channel. From this measurement, we could see that the pulsating flow has generated a strong turbulent flow mixing within the compound channel. And the turbulent flow mixing in the pulsating flow plays an effective role of enhancing the Nusselt number by making the fluid temperature uniformly within the compound channel.
        4,000원
        16.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 10년간 전세계적으로 아스팔트 포장을 재활용하는 기술이 급속도로 확산되고 있으며 노후 아스팔트 포장을 폼드 아스팔트 또는 유화 아스팔트를 사용하여 현장에서 바로 100% 재활용하는 현장 상온 재생 아스팔트 포장기술이 다양하게 적용되고 있다. 특히, 아이오와 주에서는 교통량이 적은 지방도로에서 기존 포장의 수명을 연장 시켜주는 현장 상온 재생 아스팔트 공법을 많이 적용하고 있다. 일반적으로 현장 상온 재생 아스팔트 포장층은 수분의 침투나 교통하중으로부터 보호하거나 포장설계를 만족시키기 위해 가열 아스팔트 포장으로 덧씌우기를 한다. 일반적으로 현장 상온 재생 아스팔트 포장층 위에 가열 아스팔트 포장으로 덧씌우기 할 시기는 대부분에 감독자들은 일정한 양생기간 또는 최대 함수비에 근거하여 결정하고 있다. 따라서, 본 연구에서는 감독자가 최적에 덧씌우기 아스팔트 포장 시기를 결정할 수 있도록 현장 상온 재생 아스팔트 포장층의 현장 함수비를 간단하게 측정하여 덧씌우기 시기를 결정할 수 있는 수분 감소계수를 개발하는 것이다. 먼저, 현장 상온 재생 아스팔트 포장층의 함수비를 TDR 함수량계를 사용하여 측정하였고 현장 상온 재생 아스팔트 포장이 시공되는 기간 동안에 강우량, 대기온도, 습도, 바람속도 등 기상정보를 수집하였다. 마지막으로 현장 상온 재생 아스팔트 포장의 초기 함수비, 대기온도, 습도, 바람속도를 변수로 하는 수분 감소계수를 개발하였다. 실제 현장 상온 재생 아스팔트 포장에서 측정한 값을 사용하여 개발한 수분 감소계수는 감독자가 연속적으로 현장 상온 재생 아스팔트 포장층의 함수비를 측정하지 않고 최적의 덧씌우기 포장 시점을 결정할 수 있다.
        4,000원
        18.
        2009.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.
        4,000원
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