• Nuclear Engineering and Technology
• /
• v.48 no.1
• /
• pp.211-217
• /
• 2016

Most nuclear power plants now utilize solid grounded low voltage systems. For safety and reliability reasons, the low voltage (LV) high resistance grounding (HRG) system is also increasingly used in the pulp and paper, petroleum and chemical, and semiconductor industries. Fault detection is easiest and fastest with a solidly grounded system. However, a solidly grounded system has many limitations such as severe fault damage, poor reliability on essential circuits, and electrical noise caused by the high magnitude of ground fault currents. This paper will briefly address the strengths and weaknesses of LV grounding systems. An example of a low voltage HRG system in the LV system of a nuclear power plant will be presented. The HRG system is highly recommended for LV systems of nuclear power plants if sufficient considerations are provided to prevent nuisance tripping of ground fault relays and to avoid the deterioration of system reliability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.5
• /
• pp.97-107
• /
• 2001

Many power plants in the thermal and hydraulic utilities, the pulp and the paper industry are faced with high maintenance and down time due to the aged excitation system. For the life extension of the aged power plants, the static excitation system of triple module redundancy type had been developed by KEPRI(Korea Electric Power Research Institute). This paper will discuss the design conception and the application results of system which includes the power control devices(thyristors, GTO), power potential transformer(excitation transformer) and triple module redundancy controller(voltage regulator).

• Journal of Industrial Convergence
• /
• v.12 no.2
• /
• pp.16-23
• /
• 2014

The aim of this study is to find the strategic industries that fulfills the on-site demands of the Gyeonggi province region related to the advancement and development of the local industries. As the results of the analysis, the 4 major strategic industries in the Gyeonggi province region were determined to be (1) electronic component, computer, visual, acoustic and telecommunication equipment manufacturing, (2) pulp, paper and paper product manufacturing, (3) medical substances and pharmaceutical product manufacturing, and (4) rubber and plastic product manufacturing. The industry of concordance between the 4 major strategic industry of the Gyeonggi province determined in this Study and the 13 future growth engine industry of Korea was the area of intelligent semiconductor. Accordingly, it was analyzed that there is a need to strategically cultivate the electrical and electronic telecommunication device industry, which is ranked the $1^{st}$among the strategic industries of Gyeonggi province by generating synergic effects with the policy of the government for nurturing of intelligent semiconductor industry.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.16 no.3
• /
• pp.157-170
• /
• 1998

To investigate the most effective way of cellulase utilization on paper making process and the systematic way of how to combine its components for better use, purified two major cellulase were applied to bleached kraft pulp at various dosage in the refining process and estimated the synergism effect of each components in the characteristics of papermaking fiber. freeness was not changed by $C_1$ Component dosage but strongly increased by Cx Component dosage. Drop in fiber viscosity, increase in WQV, fiber shortening and fine generation was strongly influenced by Cx Component, it seems to be that Cx Component works a hydrogenate that breaks hydrogen bonding in fiber and enhances pooling effect of fiber. $C_1$ Component was little influenced these characteristics of fiber but considered to help to make fiber surface smooth.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.466-469
• /
• 2002

Many power plants in the thermal and hydraulic utilities, the pulp and the paper industry are faced with high maintenance and down time due to the aged excitation system. For the life extension of the aged power plants, the static excitation system with SCPT type had been developed by KEPRI(Korea Electric Power Research Institute) This paper will discuss the design conception and the application results of system which includes the phase controlled rectifiers of the shunt type, SCPT and redundant analog controller.

• Proceedings of the KIEE Conference
• /
• 1998.07a
• /
• pp.263-265
• /
• 1998

This paper presents a design and Analysis of Induction Heating Roll. Heating roll is one of the induction heating's application, widespread for print, pulp, fiber industry, and so forth. In this paper, at first, treated that heating roll's characteristics equation, design method of heating roll, and then design roll. The second, analysis designed roll using FEM.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.1
• /
• pp.52-58
• /
• 2015

White ledger usually includes white office paper, computer paper, and copy machine paper. Because these grades need high optical properties, fluorescent whitening agents (FWAs) are widely used in the papermaking process. FWAs are the most powerful and effective chemical used to obtain high CIE whiteness and ISO brightness in papers. The rising demand for white or ultra-white papers has increased the use of FWAs. However, FWAs used in white ledger can restrict its use, even though white ledger is widely used as a raw material in paperboard mills. Therefore, it is necessary to develop methods to control FWAs from white ledger to increase its use in paperboard mills. In this study, the behaviors of disulpho fluorescent whitening agent (D-FWA), tetrasulpo fluorescent whitening agent (T-FWA), and hexasulpho fluorescent whitening agent (H-FWA) during the recycling process were identified as a first step to remove FWAs from white ledger. We prepared four types of papers (dyed with D-FWA, T-FWA, and H-FWA), disintegrated these papers, and made handsheets. This recycling process was carried out three times in a laboratory. After each round of recycling, the hand-sheets' CIE whiteness and fluorescence index were measured, and the distribution of FWAs in the Z-direction was observed using CLSM images. FWA reductions in the model papers were calculated using fluorescence indices as a function of the number of recycling. FWAs in handsheets containing T-FWA and H-FWA decreased linearly as a function of the number of recycling, but D-FWA did not show a significant reduction in the fluorescence index after recycling. T-FWA and H-FWA showed similar distributions of D-FWA after recycling. Therefore, as much T-FWA and H-FWA as possible must be detached in the early processes of papermaking at paperboard mills.

• Journal of Conservation Science
• /
• v.5 no.1 s.5
• /
• pp.94-104
• /
• 1996

This study was carried on paper mulberry bast fibers, which were cut in the length of it's chip by three kinds. And they cooked by sodium hydroxide (NaOH) and ammonium oxalate (AMOX), and pulping process was studied to inquire some properties of hand made papers. The results were as follows. AMOX pulps had $10\~17\%$ higher than NaOH, but amounts of the residual lignin of it's pulps and residual ash were high, and it surely can't be superior. In the freeness of pulps, AMOX pulps were higher than that of NaOH, but they showed tendency to opposite in view of relation of chip's length kinds. For the AMOX pulps, the physical characteristics test results were higher long fiber pulps than short fiber pulps. Specially, in folding endurance long fiber pulps were a very strong. NaOH pulp's physical characteristics test had shown results that were opposite of there of the AMOX pulps, if the length of the fiber is longer, the strengthts generally decreased. To get the optimum fiber's length according to use of paper and pulping method, they must be fractionate chip's length. The long fibers in NaOH pulps affected the paper quality greatly to length of chips.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.196-197
• /
• 2013

This study is the experiment for manufacturing the Lightweight non-cement matrix based on the Blast furnace slag. And, the matrix was manufactured matrix by generating the bubble just by the reaction of KOH that is the alkali accelerator and paper ash, instead of the general foaming agent, that is the waste managed of incineration the pulp sludge generated in the process of manufacturing the paper. Consequently, the density according to the addition rate of KOH represented the tendency to increase. And it showed up that density of the matrix adding KOH 22.5% was the lowest. As to the strength test result, strength following addition rate of KOH increased. Since the bubble is generated in the reaction of KOH and paper ash, this shows the very low intensity but it is determined to be the result that the amount of vacant space is decreased because the bubble generated in the mixture process comes up as the specific gravity difference.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.34 no.5
• /
• pp.1-17
• /
• 2002

The immobilization and consolidation of the model coatings based on the plastic pigment and latex binder of known particle sizes were theoretically Studied in terms of the dense random packing of binary spheres and varying extent of latex film shrinkage. The porosity of the model coatings was calculated based on three proposed latex shrinkage models: Maximum, Minimum, and Linearly Decreasing Latex Shrinkage. The increasing extent of latex shrinkage was calculated up to the critical pigment volume concentration(CPVC) as a function of plastic pigment volume fractions, and the maximum latex shrinkage was estimated from the CPVC. Also, the number of pores and the average equivalent spherical pore diameters were calculated based on those proposed models. The opacity and gloss of the model coatings on polyester films were measured and their porosity was also determined by a simple coat weight-thickness method. As expected, various coating structure-property-composition relationships, such as opacity, gloss, porosity, etc., were shown to exhibit sharp transitions near the CPVC. The CPVC values determined by the opacity, gloss, and porosity vs. PVC relationships, respectively, agreed very well with each other. Especially, the CPVC's determined by the opacity and porosity vs. PVC curves were identical. The comparison between the theoretically calculated and experimental porosity values showed that the intermediate value between the maximum and minimum latex shrinkage would best fit the experimental porosity data. The effect of plastic pigment particle size on the optical properties and porosity of model coatings was also studied and it was observed that the coating opacity and porosity increased with increasing plastic pigment particle size, but the gloss decreased. The ink gloss of the uncalendered model coatings applied onto commercial sheet offset coated papers was shown to be affected by both the coating gloss and porosity: the higher the coating gloss, the higher the ink gloss, but the higher the coating porosity, the lower the ink gloss. Their printability was also studied in terms of the number of passes-to-fail and the rate of ink setting as a function of both plastic pigment volume fractions and plastic pigment particle sizes. A minimum crack-free temperature(MCR) of latex-bound coatings was proposed to better predict the behaviors of latexes as coating binders. The wet state of model coating dispersions, the surfaces of consolidated model coatings, and their internal structure were examined by both electron and atomic force microscopy, and their micrographs were found to be consistent with our immobilization and consolidation models.