• Journal of Industrial Technology
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• v.21 no.A
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• pp.7-14
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• 2001

In building structure, the story height can be minimized by providing openings in beams which serves for the utility equipments passing through. The dead space in false ceiling thus put to economical use in the form of a substantial reduction in materials and construction cost. In the case of steel structure, there is no critical risk in the structural strength because of reinforcing methods of stiffness and steel plate but in the case of reinforced concrete structure, proper provision should be made in designing these openings, otherwise there is a risk that these opening will possibly weaken the structural strength of the building frame to a critical degree. In this paper, for the numerical analysis of the reinforced concrete beams with circular opening in the web, expecting stress concentration of the circular opening, reinforcing methods were studied. Twenty test pieces with each different reinforcing methods were tested and their resisting forces were defined. From the numerical analysis and test results, the followings were founded;(1)high shear stress distributed around the openings reduce the shearing strength, (2)from the numerical analysis, the maximum tensile stress occurred at opening nodes 1,7, these phenomena were agreed with the test results, (3)reinforcing method around openings have to carried out for stopping diagonal cracks, and (4)both, by steel plate, and wire mesh, are effective reinforcing methods.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.8-15
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• 2008

Wastewoods (logging residues) generated in Korea were used to make lignocellulosic fillers for papermaking. Lignocellulosic fillers could play great roles to increase retention efficiency and thus decrease turbidity of white water in papermaking process. In addition, lignocellulosic fillers could be used to improve physical properties of paper through their high affinity to cellulosic fibers, leading to the less use of chemical additives like retention aids. Wastewoods including Pinus densiflora and Quercus variabilis were chemically and mechanically treated for making fine particles passing through 100 mesh wire. The newly generated fillers showed larger particle size distribution than ground calcium carbonates but similar distribution to talc. In particular, pretreatment by hot water was more effective to generate smaller particle size than by alkali treatment. Lignocellulosic particles mixed with ground calcium carbonates under intense hybridizing condition greatly contributed to surface coverage of organic fillers in addition to filling to lumen and pits.

• Fire Science and Engineering
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• v.22 no.5
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• pp.83-89
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• 2008

Using the high expansion foam generator of ISO 7203-2 which spray 6 liter at 5 bar, foam generation characteristics was studied. Wind flow rate, foam screen, concentration of foam agent solution and concentration of salt of water were varied to find the effect of the parameters on foam generation. Research result showed that expansion ratio of foam was increased with wind flow rate. The expansion ratio of foam in the perforated type standard screen was higher than the wire mesh screen. Expansion ratio and drainage time were increased with increase of foam solution concentration. But a increase of salt concentration in solution showed the decrease of expansion ratio and drainage time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.417-424
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• 1987

The seeds of three barley varieties of which initial seed vigor were different were used to measure seed vigor of accelerated aging techniques. A vigor index derived from the product of percent germination and plumule length was used to estimate seed vigor. The index was compared with the results of other tests. The results of warm germination test well suited to the measurements of seed vigor at the advanced stages of seed deterioration. Other vigor measurements except ATP and GADA values, showed close relationships with the vigor index. The measurements of plumule length in cold test and tetrazolium test were found to be appropriate for predicting seed quality.

• Carbon letters
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• v.4 no.4
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• pp.168-174
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• 2003

Silver nitrate ($AgNO_3$) powder was mixed into a reformed pitch precursor. Then, the silver-containing pitch was melt spun to form round and "C" shape fibers. A wire mesh was inserted prior to the nozzle to improve the spinnability of the silvercontaining precursor pitch. Silver particles in the carbon fibers (CFs) were detected by XRD and TEM. These tests showed that silver particles were uniformly distributed and the total amount of silver remained constant during stabilization and carbonization. Next, the silver-containing CFs were activated by steam diluted in nitrogen gas. Silver particles accelerated the activation rate, but the specific surface areas of the silver-containing ACFs were similar to those of non-silver containing ACFs at the same burn-off levels. The specific surface area of the C-shaped activated carbon fibers was larger than that of the round activated carbon fibers. The likely reason is that the surface area of a C-shaped CF is about two times larger than that of a round CF when equivalent cross-sectional areas are compared. A small amount of silver particles in the periphery of the CFs was removed during the activation, but the remainder of silver was stayed within the ACFs.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.103-110
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• 2007

Concrete is a material that will crack during its service life by its very nature. For bridge decks this is especially significant as these cracks allow accelerated ingress of chlorides and the subsequent corrosion of the reinforcing steel and deck deterioration. Very-early strength latex-modified concrete (below ; VES-LMC) was developed in order to realize early-opening-to-traffic bridge deck concrete. Although there has been little research to document the degree of cracking in VES-LMC overlay, there has been a general perception among highway agencies that overlay cracking of VES-LMC, particularly early-age cracking, is a one of problems which should be solved. The purpose of this study was to analyze the cause of map, transverse and longitudinal cracking in VES-LMC and to provide a control methods for minimizing the occurrence of cracks. The proposed prevention against map and transverse cracking was verified by field applications. VES cement was modified, the unit cement contents was reduced into $360kg/m^3$ from $390kg/m^3$, the maximum size of coarse aggregate was increase into 19mm from 13mm, wire mesh and steel fibers were incorporated in concrete mixture.

• Steel and Composite Structures
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• v.20 no.6
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• pp.1305-1322
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• 2016

This paper presents the results of experimental and numerical model analyses on partially encased composite columns under concentric loads. The main objective of this study is to evaluate the influence of replacing the conventional longitudinal and transverse steel bars by welded wire mesh on the structural behavior of these members under concentric loads. To achieve these goals experimental tests on four specimens of partially encased composite columns submitted to axial loading were performed and the results were promising in terms of replacing the traditional reinforcement by steel meshes. In addition, a numerical FE model was developed using the software DIANA$^{(R)}$ with FX+. The experimental results were used to validate the numerical model. Satisfactory agreement between experimental and numerical results was observed in both capacity and deformability of the composite columns. Despite of the simplifying assumptions of perfect bond between steel and concrete, the numerical model adequately represented the columns behavior. A finite element parametric study was performed and parameters including thickness of the steel profile and the concrete and steel strengths were evaluated. The parametrical study results found no significant changes in the partially encased columns behavior due to variations of the steel profile thickness or yield strength. However, significant changes in the post peak behavior were observed when using high strength concrete and these results suggest a change in the failure mode.

• The Korean Journal of Physiology
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• v.11 no.2
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• pp.67-71
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• 1977

This study was undertaken to investigate the effect of cingulate cortical ablation upon gastric secretion and its components in rats. 23 male rats were divided into the cingulate(N=9) and the operated control(N= 14) groups. Cingulate cortex was ablated through a slit-shaped opening(1 mm in width, 5 mm in length) which was made symmetrically on both sides of, and parallel to, the sagittal suture by removing a bone flap from frontal bone on each side. In the operated control group, the surgical procedure was ended by the removal of the bone flap. Under light ether anesthesia, experimental animals were placed in a restraining jacket of fine mesh wire and gastric juice was collected for 5 hours via a canula which had been inserted through the anterior abdominal wall into the antral portion of the lumen of the stomach. Volume of the gastric juice was measured, and total acid output and free acid output were titrated with 0.04 N NaOH solution by using phenolphthalein and Topfer's reagent at indicator, and chloride ion output was estimated by means of chloridometer. Results obtained were that volume, total acid output, free acid output and chloride ion output of the gastric juice were higher significantly in the cingulate group than in the operated control group. It is inferred from the above results that the cingulate cortex exerts a fascilitatory influence upon gastric secretion and acid output in rats.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.192-193
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• 2015

음극방식은 피방식체를 일정 전위로 음극분극 하는 원리로써 외부전원을 인가하거나 비전위의 금속을 희생양극으로 연결하여 방식하는 방법이다. 해수 중에서 음극방식을 실시할 경우 음극 표면에 용존산소 환원반응과 수소발생반응이 일어나 $OH^-$ 이온이 발생하게 된다. 이러한 반응에 의해 생성되는 석회질 피막 (Calcareous deposit)은 강구조물의 부식방지를 위한 물리적인 방호벽 역할을 하면서 용존산소의 확산 및 이동을 억제하며, 전류밀도를 감소시킨다. Potentiostat 및 rectifier를 이용하여 정전위 및 정전류 조건에서 형성된 석회질 피막을 SEM, EDS, XRD를 통해 분석하고 이를 바탕으로 양극의 종류(Al, Zn) 및 1, 5, $10mA/m^2$의 전류밀도 조건에서 실제 강관에 형성된 석회질 피막의 메커니즘을 해명하였다. 또한 석회질 피막 형성 시 Steel Wire Mesh를 설치하여 그 영향에 대해서도 분석하였다. 석회질 피막의 내구성은 침지-자연전위 및 밀착성 테스트를 통해 평가되었다.

• Computers and Concrete
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• v.11 no.5
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• pp.383-397
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• 2013

Two-dimensional tensile stresses are occurring at the back of the anchorage of the tendons of prestressed concrete bridges. A new method named "tensile stress region" for the design of the reinforcement is presented in this paper. The basic idea of this approach is the division of an anchor block into several slices, which are described by the tensile stress region. The orthogonal reinforcing wire mesh can be designed in each slice to resist the tensile stresses. Additionally the sum of the depth of every slice defined by the tensile stress region is used to control the required length of the longitudinal reinforcement bars. An example for the reinforcement design of an anchorage block of an external prestressed concrete bridge is analyzed by means of the new presented method and a finite element model is established to compare the results. Furthermore the influence of the transverse and vertical prestressing on the ordinary reinforcement design is taken into account. The results show that the amount of reinforcement bars at the anchorage block is influenced by the layout of the transverse and the vertical prestressing tendons. Using the "tensile stress region" method, the ordinary reinforcement bars can be designed more precisely compared to the design codes, and arranged according to the stress state in every slice.