• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.68-74
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• 2016

Nanofibrillated cellulose (NFC) was prepared from cotton linter after electron beam irradiation to investigate its effects on the manufacturing efficiency of the NFC preparation and the property changes by the treatment. Mechanical device (Super Masscolloider) was used to prepare the NFC and its passing frequency for each NFC preparation was recorded. More electron beam irradiation resulted in less passing frequency. Alpha cellulose content, molecular weight, crystallinity index, and thermal decomposition behavior of each treatment were lowered by electron beam treatment (10 and 100 kGy) and grinding process. NFC films were prepared to investigate their mechanical properties. There were little changes in tensile properties of the NFC films.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1219-1225
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• 2018

In this study, a comprehensive laboratory experimental programme was conducted on expansive soil with a high swelling potential to study the influence of different additive materials on swelling pressure and index properties. Lime, sand, multifilament fiber and fibrillated fiber were used for stabilization of expansive soil. Lime, sand and fibers were respectively added to the expansive soil at 0-7%, 0-80%, 0-0.5%. On each mixture that was prepared by the proportions mentioned above, Atterberg limits, compaction, and swelling pressure tests were conducted. From the result of these experiments, the swelling pressure-time relation could be replaced by a rectangular hyperbola established to facilitate the prediction of ultimate percent swelling with a few initial data points. The best type of additive and its optimum ratio for engineering purposes could be estimated rapidly by this approach.

• Computers and Concrete
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• v.17 no.1
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• pp.87-106
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• 2016

This paper deals with the reliability analysis of design formulations derived for predicting the punching shear capacity of FRP-reinforced two-way slabs. Firstly, a new design code formulation was derived by means of gene expression programming. This formulation differs from the existing ones as the slab length (L) was introduced in the equation. Next, the proposed formulation was tested for its generalization capability by a parametric study. Then, the stochastic analyses of derived and existing formulations were performed by Monte Carlo simulation. Finally, the reliability analyses of these equations were carried out based on the results of stochastic analysis and the ultimate state function of ASCE-7 and ACI-318 (2011). The results indicate that the prediction performance of new formulation is significantly higher as compared to available design equations and its reliability index is within acceptable limits.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.16-23
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• 2004

Recently the increased concerns about the cost reduction and environmental protection make the paper industry increase the closure level of papermaking system, which results in the buildup of organic and inorganic materials in the papermaking process water. Increase of the system closure causes deterioration of additive performance and provokes diverse problems in papermaking process and product quality. To investigate the effects of process water quality on the physical properties of fine papers handsheets were prepared with process water containing various amounts of inorganic and organic contaminants including calcium or sodium ions and oxidized or cationic starches. Inorgainc and organic materials did not show any significant effect on the physical properties of handsheets. Recycled GCC showed the same trends as inorganic and organic materials. The performance of cationic starch was deteriorated, however, in the recycled white water, which resulted in the reduction of tensile index of handsheets.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.4
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• pp.33-38
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• 2010

The effects of fillers on the wet end dewatering and paper properties were investigated in order to confirm the possibility that the fillers can be used as a means for saving energy in papermaking process. The performance of GCC, PCC and talcs were evaluated. The dewatering in wire and wet press was improved by the increase of filler addition, but it was observed that the dewatering behavior was depended by the filler characteristics. PCC was superior to other fillers in the bulk, opacity, air permeability and stiffness while the lowest tensile and burst index were obtained. We found that the response on the wet end dewatering and paper properties were affected greatly by the filler characteristics including particle shape and size.

• Journal of Technology Innovation
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• v.11 no.2
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• pp.151-173
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• 2003

This paper analyses the efficiency and productivity of R&D system across time (1991${\sim}$2000) and 16 OECD countries using multi-output and multi-input non-parametric frontier methods such as DEA (data envelopement analysis) and Malmquist productivity indexes. Malmquist productivity indexes are decomposed into two components measures, namely technical change and efficiency change. To calculate R&D efficiency and productivity, we used R&D stock and the number or researchers as R&D input proxies and the number of adjusted SCI papers and U.S. patent applications as R&D output proxies. Empirical result shows that Switzerland, Canada, U.S., Australia's R&D efficiencies are the highest and Korea's R&D productivity growth is the highest in the sample for the period. Technical efficiency growth was a more important source of productivity growth than technological innovation.

• Ocean and Polar Research
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• v.25 no.4
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• pp.437-446
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• 2003

Field measurements of directional waves were carried out during the summer of 2002 at two coastal sites in water of finite depth. A couple of general purpose instruments were used employing acoustic Doppler technology. The aim of the study was to investigate the spatial behavior of the directional movement of waves as they come ashore. In total,74 tests were carried out during which sea states of low to moderate intensity were recorded. A great number of these runs displayed bimodal characteristics of the spreading function at high frequencies. It was found that in general, the frequency-integrated directional width tends to broaden as the water shoals and when refraction effects are negligible. This is attributed to wave-wave interactions that become pronounced in shallow water. The same directional width showed, also, a tendency to increase with increasing peak frequency of the sea state spectrum. The behavior of the kurtosis of the spreading function was also examined. It was found that for higher frequencies this index tends to increase in wave spectra above a certain sea severity threshold.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.3
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• pp.57-64
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• 2000

This study was carried out to acquire basic data necessary for the use of non-wood pulp. It investigated various chemical pulping methods using bamboo to achieve higher yield lower kappa no. and then the physical properties of various pulps were tested. The results of this study were as follows. When various chemical pulps(Soda, Soda-AQ, Soda-AQ-H2O2, Soda-urea, AS, AS-AQ, Kraft) were produced with bamboo. the pulps with the higher yield and lower kappa no. were AS-AQ and Kraft. In the case of the breaking length Soda pulps(5.77∼6.46 km) showed the greatest and Soda-urea pulps(3.81∼4.522km) showed the lower value. Similarly for the burst index Soda pulps (3.28∼3.50 kPa$.$m2/g) were the best and Soda-urea pulps(2.29∼2.39 kPa$.$m2/g) were worst. On the other hand the tearing indexes of AS-AQ pulps(73.6∼89.7mN$.$m2/g) showed the tendency which was higher then those of other pulps.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.149-152
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• 1999

A new process for deinking of colored offset newsprint, i.e. enzyme treatment in cooperation with ultrasonic wave was developed in the present study. The physical characteristics such as fiber length, coarseness, crystallinity index of the deinked pulps were investigated and the sugar residues released from the treatment were analyzed. It was found that colored offset newsprint could be deinked effectively by cellulase treatment when ultrasonic wave was applied. The brightness increased by 5% ISO over that of control experiment and the pigment content was reduced markedly. Though the ultrasonic wave had little effect on the strength and crystallinity of the pulp, the treatment of enzyme combined with ultrasonic wave reduced the coarseness and fiber length to some extent. It was also found that ultrasonic wave could accelerate the hydrolysis of cellulose and hemicellulose during the cellulase treatment.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.191-198
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• 2010

This paper selects length of berth, area of yard, unloading capacity and number of berth as the input indexes, and cargo turnover as output index to research the source of turnover growth of 22 main ports in Korea. We gains the following results: in general, the trade ports in Korea are the stage of expansion period, the sources of turnover growth depends on the growth of factor inputs and could not be supported by TFP and technical progress. Especially in the west and east coast, TFP and technical progress is the block to the turnover growth. Four major factors to the increase of TFP are following: competition between ports, reform of property system, harbor-hinterland economic and international trade, modeling, imitation and innovation in management, technology and system.