• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.2
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• pp.5-12
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• 1998

Exploitation of the papermaking technology to reduce the strength loss that accompanies when using recycled papers as raw materials for papermaking is one of the most important issues imposed upon today's paper industry. Multi-layer sheet forming technology has been suggested as a way that provides some answers to this issue. In this study strength properties of single- and two-layer handsheets formed with recycled fiber and unbleached softwood kraft pulp have been examined to quantify the benefits when using two-layer sheet forming technology rather than a conventional single layer sheet forming precess. Single- and two-layer handsheets were made from 50% of OCC and 50% of Sw-UKP and their strength properties were evaluated. Also the strength properties made from Sw-UKP and OCC sheets were determined. A multihead, which can be attached on the top of hand- sheet former, was used to form two-layer sheets. Maximum strength properties could be obtained in the freeness range of 500∼300mL CSF for Sw-UKP Most of the strength properties was reduced by 30∼35% when 50% OCC was blended with UKP. Decrease of strength properties, however, could be reduced by employing a two-layer sheet forming method. Creator strengths could be obtained when UKP was positioned at the top layer of two layered sheets indicating greater UKP fines retention due to the filtration effect of the OCC layer formed prior to UKP layer contributed the strength improvement. Two-layer sheet showed lower Scott internal bond strength than single layer sheet. By incorporating some of UKP fibers into OCC layer this reduction could be reduced.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.4
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• pp.7-14
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• 2001

Recycled fibers usually give slow drainage in the paper forming process, which limits the application of more refining to the recycled fibers for improving paper strength and formation. To use recycled fibers more effectively, especially OCC, developing very efficient handling technique of short fibers and fines is inevitable. We tried to make hard flocs of fractionated short fibers and fines, which were the main cause of slow drainage, by adding excessive amount of retention aid selectively on them. This technique was proved to increase drainage considerably, but to decrease strength properties, compared to the conventional technique of adding the same amount of polymers to the whole furnish in the lab test. The bonding capability of short fibers and fines in Korean OCC was very poor. Various chemical treatment on the short fibers and fines of the Korean OCC did not improve their bonding and optical properties. One of the reasons of no improvement in their properties was their high amount of ashes.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.63-75
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• 2003

• Journal of Korea Foundry Society
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• v.28 no.4
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• pp.154-159
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• 2008

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2005.04a
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• pp.100-107
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• 2005

• The KIPS Transactions:PartD
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• v.8D no.2
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• pp.132-144
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• 2001

The broadcast environment is asymmetric communication aspect that is typically much greater communication capacity available from server to clients than in the opposite direction. In addition, most of mobile computing systems only allow the generation of read-only transactions from mobile clients for retrieving different types of information such as stock data, traffic information and news updates. Since previous concurrency control protocols, however, do not consider such a particular characteristics, the performance degradation occurs when those schemes are applied to the broadcast environment having quite a high data contention. In this paper, we propose OCC/2VTS (Optimistic Concurrency Control based on 2-Version and TimeStamp) that is most appropriate for broadcast environment. OCC/2VTS lets each client process and commit query transactions for itself by using two version data in cache. If the values of appropriate data items are not changed twice by invalidation report after a query transaction starts, the query transaction is committed safely independent of commitment of update transactions. OCC/2VTS decreases the number of informing server for the purpose of commitment. Due to broadcasting the validation reports including updated recent values, it reduces the opportunity of requesting a recent data values of server as well. As a result, OCC/2VTS makes full use of the asymmetric bandwidth. It also improves transaction throughput by increasing the query transaction commit ratio as much as possible.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.185-194
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• 2002

Most of mobile computing systems allow mostly read-only transactions from mobile clients for retrieving various types of Information such as stock data, traffic information and news updates. Since previous concurrence control protocols, however, do not consider such a particular characteristics, the performance degradation occurs when previous schemes are applied to the broadcast environment. In this paper, we propose OCC/UTF(Optimistic Concurrence Control with Update Transaction First) that is most appropriate for broadcast environment. OCC/UTF lets a query transaction, that has already read the data item which was invalidated by update transaction, read again the same data item without the abort of the query transaction due to non-serializability. Therefore, serializable order is maintained and the query transaction is committed safely regardless of commitment of update transactions. In OCC/UTF, Clients need not require server to commit their query transactions. Because of broadcasting the validation reports including values updated recently to clients, it reduces the overhead of requesting recent values from the server and the server need not also re-broadcast the newest values. As a result, OCC/UTF makes full use of the asymmetric bandwidth. It can also improve transaction throughput by increasing the commit ratio of query transactions as much as possible.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.367-373
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• 1999

Increasing consumer demand for recycle of most paper products is challenging manufacturers to use lower value raw materials while maintaining high quality. This study was carried out to investigate the composition of old corrugated containers (OCC) and to manufacture printing and writing papers of over 85% (ISO) brightness by ECF and TCF bleaching from OCC. Fiber length of American old corrugated container (AOCC) was longer than that of Korean old corrugated container (KOCC) in fiber length. The former was composed of unbleached kraft pulp (UKP) of about 80 percentage, the latter about 20 percentage. OCC is feasible for manufacturing of pulps i.e., AOCC is for printing and writing papers and KOCC is for whiteboards, in the aspects of brightness and mechanical properties on the other hand, the cost of manufacturing upgraded papers by OCC is high because of bleaching chemicals. Neverthless, considering various aspects, especially environment, there are many advantages in recycling. In case of the treated AOCC pulp, over 85% (ISO) brightness can be achieved through TCF or ECF bleaching step, while the treated KOCC pulp did not allow high brightness through TCF bleaching. The tensile index of the bleached KOCC pulp was lower than that of the bleached AOCC pulp, but the burst and tear index of KOCC was higher than that of AOCC.

• Ocean and Polar Research
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• v.42 no.1
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• pp.49-61
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• 2020

We analyzed the morphological characteristics of OCC (Ocean Core Complexes) in the middle part of the Central Indian Ridge (MCIR) using high-resolution geophysical data recorded on the Deep-Tow SideScan Sonar IMI-30 system. In terms of slope-gradient variations calculated from the high-resolution bathymetry data, the normal faults formed by seafloor spreading were associated generally with slopes > 30° and resulted in high backscatter intensities, which reflect more topographic effects than acoustic medium variation. However, the areas associated with gentle slopes < 10° tend to show the backscatter intensities reflecting the acoustic characteristic of the medium. We show that the detachment faults exposing the OCCs were initiated with high-angle normal faults (58°) exhibiting outward and inward dips of a breakaway zone. In order to examine the spatial distribution of OCC structures, we characterized the transition from magmatic-dominant seafloor with abyssal hills to tectonic-dominant seafloor with OCC using the down-slope direction variation. The slope direction of the seafloor generally tends to be perpendicular to the ridge azimuth in the magmatic-dominant zone, whereas it becomes parallel to the given ridge azimuth near the OCC structures. Therefore, this spatial change of seafloor slope directions indicates that the formation of OCC structures is causally associated with the tectonic-dominant spreading rather than magmatic extension. These results also suggest that the topographical characteristics of seafloor spreading and OCC structures can be distinguished using high-resolution geophysical data. Thus, we propose that the high-resolution bathymetry and backscatter intensity data can help select potential areas of exploitation of hydrothermal deposits in MCIR effectively.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.3 s.32
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• pp.71-76
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• 2004

The power consumption of TEC for Laser diode cooling was predicted by 3-D FEM simulation and verified by experiment. The operating conditions such as power consumption of Laser diode, set temperature, ambient temperature, resistance of thermal path was considered to estimate the TEC power consumption. Using 3-D FEM simulation, the relation between TEC configuration defined by the pellet dimension and the number and power consumption was investigated for low power consumption scheme. As a result, as the thermal resistance of the pellet increased, the power consumption decreased.