• Applied Biological Chemistry
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• v.26 no.2
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• pp.104-109
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• 1983

Gas chromatographic method for the analysis of phorate(0,0-diethyl S-ethyl-thiomethyl phosphorithioate) and its metabolites in soil and vegetables was studied by using a mixed phase column(10% DC-200+8% Reoplex-400+2% QF-1 on Gas Chrom Q, $1.8{\times}2mm$ i.d, borosilicate glass column). This column can separate completely phorate and its four metabolites except phoratoxon sulfoxide. Retention time of standard mixture ranged 1.8 to 16.1 minutes at column temperature programming from 130 to $200^{\circ}C$ at $5^{\circ}C/min$ and detector sensitivity was also very high(0.05 to 1.05ng). Recoveries from soil and vegetables untreated but fortified with phorate and its three major metabolites at 0.05 and 0.5ppm levels were above 90% for phorate, phorate sulfoxide and phorate sulfone while recovery of phoratoxon metabolite was about 84%.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.1-8
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• 2009

Photobioreactor (PBR) that houses and cultivates microalgae providing a suitable environment for its growth, such as light, nutrients, CO2, heat, etc. is now getting more popular in the last decade. Among the many types of PBRs, the bubble column type is very attractive because of its simple construction and easy operation. However, despite the availability of these PBRs, only a few of them can be practically used for mass production. Many limitations still holdback their use especially during their scale-up. To enlarge the culture volume and productivity while supplying optimum environmental conditions, various PBR structures and process control are needed to be investigated. In this study, computational fluid dynamics (CFD) was economically used to design a bubble-column type PBR taking the place of field experiments. CFD is a promising technique which can simulate the growth and production of microalgae in the PBR. To study bubble column PBR with CFD, the most important factor is the possibility of realizing bubble. In this study, multi-phase models which are generally used to realize bubbles were compared by theoretical approaches and comparing in a 2D simulation. As a result, the VOF (volume of fluid) model was found to be the most effective model to realize the bubbles shape as well as the flow inside PBR which may be induced by bubble injection. Considering the accuracy and economical efficiency, 0.005 second time step size was chosen for 2.5 mm mesh size. These results will be used as criteria for scale-up in the PBR simulation.

• Korean Journal of Food Science and Technology
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• v.8 no.2
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• pp.85-89
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• 1976

The separation and determination of dicarbonyls such as diacetyl, methylglyoxal and triose reductone in their mixed aqueous solution were carried out by means of gas chromatography with transformation of these compounds into quinoxaline derivatives with o-phenylenediamine. A column used for this experiment was consisted of Celite 545 (80-100 mesh) coated with 5% Silicon Gum SE-30. The column temperature was $180^{\circ}C$. It is desirable that this approach will be applicable to dicabonyl study in gas chromatographic determination.

• Journal of Fashion Business
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• v.13 no.2
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• pp.78-86
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• 2009

When scouring and contraction finishing at $90^{\circ}C$ using Relaxer or Rotary Washer contraction and weight loss ratio in warp and weft directions were excellent. Also surface state of fabric after drying or sanding treatment was excellent without crease. Low melting polyester fabric showed a complete melting bond by heat setting(P/S) at above $160^{\circ}C$. The alkali hydrolysis reaction of polyester showed the breakpoint in the weight loss behavior test, polyester yarn showed a breakpoint ranging from 25% to 28%. This is due to the difference of the hydrolysis rate between regular polyester and soluble polyester. Initially the soluble polyester was eluted and micro-fibrillized 5 times faster than a regular polyester. At a later time, a regular polyester was reduced weight to impart a proper flexibility and drape property to the fabric. As a result of surface sanding finishing, the surface of interior fabric showed a surface state most stabilized when using Mesh No. 220 in mono 0.2d after elution finishing. When the rotation direction of sanding roller was pro-, pro-, pro-, and retro-direction, a directional effect of tuft was not shown, a writing effect as suede was exhibited and a surface state was even. Sublimation fastness was 3-4 class for polyester and 2-4 class for nylon. Light fastness 3-4 class after lapse of 100 hours and 2-4 class after lapse of 160 hours. Abrasion fastness was 3-4 class on wet and 4-5 class on dry Laundry fastness was 2-4 class. As such, the abrasion fastness is slightly reduced upon wetting and the use thereof for interior is excellent, whereas laundry fastness is slightly lowered.

• Wind and Structures
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• v.29 no.6
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• pp.405-416
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• 2019

Aerodynamic characteristic of a small scale wind turbine under the influence of an incoming uniform wind field is studied using k-ω Shear Stress Transport turbulence model. Firstly, the lift and drag characteristics of the blade section consisting of S826 airfoil is studied using 2D simulations at a Reynolds number of 1×10⁵. After that, the full turbine including the rotational effects of the blade is simulated using Multiple Reference Frames (MRF) and Sliding Mesh Interface (SMI) numerical techniques. The differences between the two techniques are quantified. It is then followed by a detailed comparison of the turbine's power/thrust output and the associated wake development at three tip speeds ratios (λ = 3, 6, 10). The phenomenon of blockage effect and spatial features of the flow are explained and linked to the turbines power output. Validation of wake profiles patterns at multiple locations downstream is also performed at each λ. The present work aims to evaluate the potential of the numerical methods in reproducing wind tunnel experimental results such that the method can be applied to full-scale turbines operating under realistic conditions in which observation data is scarce or lacking.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.359-370
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• 2006

The objective of this study was to investigate the effect of excessive occlusal loading on stress distribution on four type of cervical lesion, using a three dimensional finite element analysis (3D FEA). The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. Four different lesion configurations representative of the various types observed clinically for teeth were studied. A static point load of 500N was applied to the buccal and lingual cusp (Load A and B). The principal stresses in lesion apex, and vertical sectioned margin of cervical wall were analyzed. The results were as follows 1. The patterns of stress distribution were similar but the magnitude was different in four types of lesion 2. The peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 3. The compressive stress under load A and the tensile stress under load B were dominant stress. 4. Under the load, lesion can be increased and harmful to tooth structure unless restored.

• Advances in concrete construction
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• v.5 no.5
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• pp.451-468
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• 2017

The problem of reducing the self-weight of reinforced concrete structures is very important issue. There are two approaches which may be used to reduced member weight. The first is tackled through reducing the cross sectional area by using voids and the second through using light weight materials. Reducing the weight of slabs is very important as it constitutes the effective portion of dead loads in the structural building. Eleven slab specimens was casted in this research. The slabs are made one way though using two simple supports. The tested specimens comprised three reference solid slabs and eight styropor block slabs having (23% and 29%) reduction in weight. The voids in slabs were made using styropor at the ineffective concrete zones in resisting the tensile stresses. All slab specimens have the dimensions ($1100{\times}600{\times}120mm$) except one solid specimens has depth 85 mm (to give reduction in weight of 29% which is equal to the styropor block slab reduction). Two loading positions or cases (A and B) (as two-line monotonic loads) with shear span to effective depth ratio of (a/d=3, 2) respectively, were used to trace the structural behavior of styropor block slab. The best results are obtained for styropor block slab strengthened by minimum shear reinforcement with weight reduction of (29%). The increase in the strength capacity was (8.6% and 5.7%) compared to the solid slabs under loading cases A and B respectively. Despite the appearance of cracks in styropor block slab with loads lesser than those in the solid slab, the development and width of cracks in styropor block slab is significantly restricted as a result of presence a mesh of reinforcement in upper concrete portion.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.61-70
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• 1986

In accordance with a rapid growth of demani on aquatic animals, researches of the unused fishery resources On the deep sea b~d in the Korean Waters has been and will be required. The authors carried out a series of fishing experiments to investigate the available resources and to find the effective fishing method on the deep sea bed of the Korean East Sea. In the experiments, 19 kinds of traps which are different from each other in shape, mesh size and entrance diameter were used. The fishing experiments w~r;; carried out in four areas of 20Dm, 600.'11, 800m and 1000.'11 deep respectively, by the Pusan 402 (30:) GT) and the Pusan 403 (279GT), the training ships of National Fisheries University of Pusan, during August, 1986. The catc~ were analyzed with the size, the depth and the construction of traps. The results obtained can be summarized as follows: 1. Main species of the catch w~re pink shrimp, Pandalus bolelis, a kind of welks, Buccimum striatissimum and a kind of larg~ crabs. Chiono8cetes japonicus and the another species were few. 2. The CPUE value (expressed by the number of catch per trap in this paper) of pink shrimp was the highest in the depth of 20J-n around, and the value in the depth of 600.'11 or more decreased gradually with an increase of the depth. But, the value of Buccimum straitissimum was much higher in the depth of 6:J:)!1I or more than that in the depth of 200m around. On the other hand, the value of Chion:Jecetes japonjcus was very low in general. 3. The iniividual body size of the catch differed with the depth. Pink shrimps caught in the depth of 200m around were smaller than those in the depth of 600.'11 or more. In contrast with this, Baccimum striatissim:t.m caught in the depth of 200m around were larger than those in the depth of 600.'11 or more. 4. Depending on the selection curve in Ishida's method for the mesh size of trap webbing, the carapace length of pink shrimp and the shell length of Buccimum striatissimum which are equivalent to 100% relative catching efficiency can be estimated about 3.5cm and 6.5cm or so respectively. 5. The number of catch of pink shrimp and Buccimum striatissimum by the 60.'1'1.'11 entrance diameter of trap were less than that by the 90mm, 120mm and 150mm, even thogh the diffierence am~r, g 9:Jmm, 120.'11.'11 and 150:1'.'11 are not so large.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.479-484
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• 2008

The application of microwave technology has been investigated in the remediation of diesel-contaminated soil. The paper deals with economic assessment by means of cost analysis and degradation characteristics at different microwave powers for total petroleum hydrocarbon (TPH) in diesel contaminated soils. The soils from S Mountain around the D University were sampled. The samples were screened with 2.0 mm mesh and dried for 6 hours before the diesel was added into the dried soils. The diesel-contaminated soil (3,300 mg THP/kg soil) was prepared with diesel (S Co.). The drying process was carried out in a microwave oven, a standard household appliance with a 2,450 MHz frequency and 700 W of power. The experiments were conducted from 0 to 20 minutes as the microwave powers increased from 350W to 500W to 700W. The concentrations of TPH were analysed using a gas chromatography/mass spectrometer (GC/MS). The initial concentration of TPH was 3,300 mg TPH/kg soil. The weight of contaminated soil was 200g. The concentration of TPH was decreased to 1,828 mg TPH/kg soil (44.7%), 1,347 mg TPH/kg soil (59.2%) and 1,014 mg TPH/kg soil (69.3%) at 350W, 500W and 700W for 15 minutes respectively. In addition, the curve was best fit with first order kinetics using the least-square method. The ranges of a first order rate constant k and r-square were $0.0298{\sim}0.0375min^{-1}$ and $0.9373{\sim}0.9541$ respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.241-248
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• 1986

New Paint, Stapol N-6200D, products from Song Woun Industrial Co. Ltd., was tested on its chemical effect on fouling organisms attached to fishing nets. Two kinds of fishing nets with different mesh size, 5 mm (cage culture net) and 33 mm (set net) were painted and attached to $1m^2$ PVC quadrates. The quadrates with painted or non-painted fishing nets were placed at the surface water layer of southern coast of Korea. Monthly species composition and abundance of fouling organisms were analysed as well as total weight of fouling organisms including mud on fishing nets. On the other hand, anti-fouling effect of the organisms and mud on different color paints was studied and the durability of chemical effect of painted fishing net on fouling organisms was also estimated.