• Geomechanics and Engineering
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• v.9 no.6
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• pp.743-755
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• 2015

It is well known that the quality of sample significantly determines the accuracy of soil parameters for laboratory testing. Although sampling disturbance has been studied over the last few decades, the theoretical investigation of soil disturbance due to sampling penetration has been rarely reported. In this paper, an analytical solution for estimating the soil disturbance due to sampling penetration was presented using cavity expansion method. Analytical results in several cases reveal that the soil at different location along the sample centerline experiences distinct phases of strain during the process of sampling penetration. The magnitude of induced strain is dependent on the position of the soil element within the sampler and the sampler geometry expressed as diameter-thickness ratio D/t and length-diameter ratio L/D. Effects of sampler features on soil disturbance were also studied. It is found that the induced maximum strain decreases exponentially with increasing diameter-thickness ratio, indicating that the sampling disturbance will reduce with increasing diameter or decreasing wall thickness of sampler. It is also found that a large length-diameter ratio does not necessarily reduce the disturbance. An optimal length-diameter ratio is suggested for the further design of improved sampler in this study.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.129-134
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• 2014

We have developed a cost-effective and facile method to manufacture a pouch-type chemical vapor sampler. Originally, the sampler was developed by U. S. Army Natick Soldier Research, Development, and Engineering Center(NSRDEC) to determine the protective capability of individual protective ensembles or Man-in-Simulant Test (MIST). They used a selectively permeable high density polyethylene(HDPE) as front membrane and aluminum/ Nylon barrier film as an impermeable back sheet in order to mimic the actual adsorption process that occurs when the skin is exposed to chemical weapons. However, it costs over twenty dollars per sampler and the minimum of quantity is 2500 per order. In addition, it is inconvenient to employ a variety of adsorbents into the sampler, which could prevent MIST researchers to do various tests for development of MIST methodologies. Here, we report the simple method to manufacture the sampler in a laboratory scale. All the materials we used are easily obtainable and inexpensive. In addition, all the procedures we perform are generally known. We used methyl salicylate(MeS) vapor to be adsorbed into the sampler and employed several different adsorbents to evaluate the performance of samplers. The results obtained by home-made samplers and commercially avaliable one showed no significant differences. Also, MeS vapor was selectively adsorbed into the sampler depending on adsorbents. We conclude that home-made samplers are capable of collecting any kind of chemical vapor for a variety of purposes.

• Communications of the Korean Mathematical Society
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• v.14 no.3
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• pp.629-629
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• 1999

• Journal of Environmental Science International
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• v.2 no.3
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• pp.207-216
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• 1993

The concentrations of $SO_2$ and $SO_3$ were measured to estimate a new developed long time exposure $SO_2$ sampler at Onsan industrial area considering the meteorological factors from June to October, 1992. The mean concentration of $SO_3$ by $PbO_2$ method was 0.924 mg $SO_3 / 10cm^2$ $PbO_2$/day and their high values were shown in the center of the industrial area, which show potential pollution due to the increase of industrial activities and micrometeorological factors in and around the sites. As a result of statistical correlation between $SO_2$ concentration by new sampling method and $SO_3$ concentration by $PbO_2$ method in July and August, 1992, correlation coefficients were high (r=0.87, 0.91) and shown more than 0.83 value in the high concentration data set, which was arbitrarily divided into 7~10${\mu}l$$SO_2$ concentration in an attempt to further investigate these relationships. Therefore, use of new developed long time exposure TEX>$SO_2$ sampler is good for TEX>$SO_2$ measurement and valuable for estimation of air quality in the urban and industrial area. Key Words : a new developed long time exposure TEX>$SO_2$ sampler, correlation coefficients, high, $SO_2$ measurement, estimation of air Quality.

• Ocean and Polar Research
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• v.22 no.2
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• pp.57-67
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• 2000

Time-selective self-triggering water sampler, AUTTLE developed by Jin et al. (1999) has been improved in order to prevent pre-deposition of suspended sediments (SS) before sampling. By using two solenoids, the improved sampler is able to be moored or deployed with inclination. Its position is changed to horizontal position by activating the first solenoid, and then the endcaps of the sampling bottle are closed by the second solenoid that is driven three times to minimize possible failure of sampling. An external control unit for setting sampling time has been also constructed. Additionally, the electric circuit housing of the sampler has been modified to be detached from the sampling bottle when operating manually. Its performance has been confirmed through flume tests and a field experiment. It will serve as a valuable tool in the various fields of oceanography and environmental engineering, especially where seawater sampling synchronized at several sites and/or the information in storm period is important.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.158-164
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• 1999

This study was carried out to investigate total suspended particulates (TSP) in Iksan area collected by nine stages Anderson air sampler and High volume air sampler from Jul. 1996 to Jul. 1998.The results are as follows1. The average of TSP concentration to be collected by Anderson air sampler and High volume air sampler in Iksan city are $59{\mu}g/m^3$, $67{\mu}g/m^3$. It was below the level of environmental standard. 2. The average of TSP concentration by measured method are HVAS > AS > Gov. 3. The average of TSP concentration on seasonal change are higher spring than winter. It were $65.5{\mu}g/m^3$ of Spring, $57{\mu}g/m^3$ of Summer, $52.5{\mu}g/m^3$ of Fall, $61{\mu}g/m^3$ of Winter. 4. Particle size 3istribution of atmospheric particulate was divided into two groups, coarse group was made by particles larger than $1.1-2.1{\mu}m$ in diameter and fine groups smaller than $1.1-2.1{\mu}m$ in diameter. about 50% of total suspended particle measured by Anderson air sampler during the sampling period was coarse particle.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.483-491
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• 2004

The purpose of this study is to develop an ozone passive sampler and to evaluate its performance p-Acetamidophenol using as the reagent for ozone reacts specifically with the ambient ozone to produce a fluorescence material (p-acetamidopheonl dimer). The volume of absorbent solution and the extraction time determined at suitable conditions for measuring ozone were 100$\mu$L and 60 min, respectively. The changes of fluorescence were observed with incresing the storage period of passive samplers in ambient air. but the cool storage in a refrigerator did not remarkably influence the increase of fluorescence. The measurement for the precision oi the passive sampling was carried out with duplicate measurement of passive samplers. The intra-class correlation coefficients of passive samplers using dry and wet filters were 0.992 and 0.962, respectively The results from field validation tests indicated practical agreement (dry filter: r=0.963, wet filter: r=0.995) between the passive sampler and an UV photometric $O_3$ analyzer. The limit of quantification of ozone passive samplers with sampling time of 8 hr (wet filter) and 24 hr (dry filter) were 8.0 ppb and 2.7 ppb, respectively.

• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.788-791
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• 2001

An improved double-cylinder hammer-driven sampling device was designed to extract undisturbed soil cores. The improvements consist of 1) separation of hammer from the driving head, 2) a split inside cylinder, and 3) a plastic sample holder. Pushing the sampler deep into the soil before hammering would result in less compression of the sample. Core samples should be taken in soils of medium moisture content. The improved soil core sampler provides sufficiently accurate volumetric soil samples with original soil layers and soil cores of 40cm in length and 5cm in diameter.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.1-8
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• 2016

In this study, we investigated the applicability of a short-term carbon dioxide ($CO_2$) passive sampler using turbidity change in a solution containing barium hydroxide ($Ba(OH)_2$). The mass of $CO_2$ introduced into the $Ba(OH)_2$ aqueous solution was strongly correlated ($r^2=0.9565$) to the change in turbidity caused by its reaction with the solution. The sampling rates calculated for 1 h and 24 h were $42.4{\pm}5.4mL\;min^{-1}$ and $2.3{\pm}0.3mL\;min^{-1}$, respectively. Both unexposed (blank) and exposed samplers remained stable during the storage period of at least two weeks. The detection limits of the passive sampler for $CO_2$ were 81.5 ppm for 1 h and 61.5 ppm for 24 h. Based on the results, the passive sampler using the change of turbidity in the $Ba(OH)_2$ aqueous solution appears to be a suitable tool for measuring short-term atmospheric concentrations of $CO_2$.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.109-110
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• 2002

환경대기 중의 오염물질의 농도를 표시하고 계산하는 방법은 물질의 종류에 따라 다른 방법을 사용하지만 동일한 연구대상공간에서의 측정결과는 측정목적에 부합하는 방법으로 측정한 결과에 따라 유의미한 정보를 창출하게 된다. 본 연구에 사용된 Passive sampler법은 전원 및 기타장비, 기술 등이 필요치 않아 시ㆍ공간적 제약이 적어 광범위한 지역에 대한 동시 측정의 목적으로 활용될 수 있다.(UNEP/WHO, 1994). (중략)