• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.814-817
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• 2004

Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on. durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three countermeasures such as increase in design strength upto $350kg/cm^2$, application of ggbf slag powder, and concrete sealer. Of these, the method of increase in design strength upto $350kg/cm^2$ showed better durability for deterioration by de-icer salt.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.523-526
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• 2005

In order to traffic safety during winter season, snowfall and cold area has been spread the deicing chemicals, and the spraying amount is increasing every year. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, the source of substantial cost penalties due to their corrosive action and acceleration to deterioration concrete structures. Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three methods such as increase in design strength upto 32MPa application of granulated blast furnace slag powder, and concrete sealer. Of these, the method of increase in design strength upto 32MPa showed better durability for deterioration by de-icer salt.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.221-224
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• 2005

In order to traffic safety during winter season, snowfall and cold area has been spread the deicing chemicals, and the spraying amount is increasing every year. Use of deicing chemicals has been and will continue to be a major part of highway snow and ice control methods. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. Extensive use of chloride deicers is, however, the source of substantial cost penalties due to their corrosive action and acceleration to deterioration concrete structures. Deterioration due to de-icer salt occurs in practice in concrete pavement, dike, barrier and similar structure. This paper reports the results of effect of de-icer salt on durability of concrete structure in winter. To protect concrete structure from damage by de-icer salt in winter, the exposure test was performed using three methods such as increase in design strength upto 35MPa application of granulated blast furnace slag powder, and concrete sealer. Of these, the method of increase in design strength upto 35MPa showed better durability for deterioration by de-icer salt.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2006.09a
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• pp.105-108
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• 2006

본 준설토 투기장은 국제도시 부산의 관문이 될 부산신항만 입구부에 위치한 관계로 아름답고 튼튼한 호안이 될 수 있도록 하였다. 본 사업은 부산신항만 개발 중 발생하는 준설토를 수용하는 호안 축조공사로서, 적용된 설계사례 및 설계특화내용을 설명하고자 한다. 지형적 특성상 복잡한 형태의 고파랑작용으로 수리학적으로 월파, 반사파, 연파를 제어하는 경사호안 구조물을 도입하였고, 개선된 S.C.P 연약지반 처리공법을 적용하여 기초굴착 없는 친환경적이고 배수기능을 향상시킨 융기토 유용형 S.C.P공법을 적용하였다. 호안전구간은 친수 개념을 도입하였으며, 호남도 주변 해양생태계 보호를 위하여 미티케이션 개념을 도입하여 환경복원 계획 및 생태형 친수호안을 구상하였다.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.46-52
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• 2001

SMAC method, one of the numerical simulation techniques, is modified from the original MAC method for the time-dependent variation of fluid flows. The Navier-Stokes equations for incompressible time-dependent viscous flow are applied, and Also marker particles which present the visualization of fluid flows are used. In this study, two-dimensional numerical simulations of the overtopping are carried out by SMAC method, and the simulation results are visualized, In addition to, motion pictures are made for efficient visualization of the simulation results. This numerical simulation could also be applied to the design of coastal structures as dike and revetment.

• Geomechanics and Engineering
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• v.6 no.1
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• pp.65-77
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• 2014

Geosynthetic tubes inflated with water, clay slurry or sand have been widely used for large dike construction in land reclamation projects. In this paper, analytical solutions for geosynthetic tube resting on rigid foundation is presented by adopting an approach similar to that presented by Leshchinsky et al. (1996). The proposed method allows a quick preliminary design to be made for using a closed-form solution. To simplify the analysis, relationships between geometrical parameters and pumping pressure are established using numerical method. The analytical solutions were compared with several existing solutions and good agreements were achieved.

• International Journal of Knowledge Content Development & Technology
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• v.12 no.1
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• pp.49-65
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• 2022

This study examined e-resources usage among polytechnic students in Southwest Nigeria. A descriptive research design was adopted for this study and the population consisted of polytechnic students from The Polytechnic, Ibadan and Federal Polytechnic, Ede. There were 9671 students from both polytechnics. A multi-stage sampling technique was employed with a sample fraction of 5% was drawn from the total number of students in each faculty amounting to 381. A structured questionnaire was the major instrument used for data collection and the questionnaire was pre-tested using Cronbach-alpha to determine the reliability co-efficient. Data obtained was analyzed using SPSS. The study found that the students from both polytechnics are aware of the e-resources and that the e-resources were mainly used for research, class assignment and to update knowledge. The problem such as epileptic power supply, poor internet connection and so on was identified. The study concluded that polytechnic students could benefit immensely from the enormous usage of e-resources particularly for teaching, learning and research. Based on the findings, recommendations were made.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.5
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• pp.43-51
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• 1998

In design and management of sea0dikes, engineers need to study various transient seepage conditions through dikes not only for the sea water infiltration into dikes due to cyclic rises of sea water level also for the seepage flow out from dikes toward the sea due to cyclic drawdown of sea water level. Characteristics of seepage flow toward the sea from dikes are more complicated than as known and remained unclearly. The case of such seepage flow may be explained by figuring out seepage characteristics in filter as a part of sea-dikes. Filters in most sea-dikes in Korea are inevitably placed with reversely inclined shape due to field construction conditions. Most computer programs for seepage analysis based on the various numerical methods give practically acceptable results, but for the case of reversely inclined section of filters any verification to apply them might be needed. In this study, large scaled model tests were executed to verify and understand seepage flow through earth-filled sea-dikes. The results from numerical analysis and model tests show some remarkable differences in pore pressure distribution under cyclic changes of see level, and some of the results need to be considered in design and construction practices with further study.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.35-41
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• 2007

In general, coastal damage is mostly occurred by the action of complex factors, like severe water waves. If the maximum storm surge height combines with high tide, severe water waves will overflow coastal structures. Consequently, it can be the cause of lost lives and severe property damage. In this study, using the numerical model, the storm surge was simulated to examine its fluctuation characteristics at the coast in front of Noksan industrial complex, Korea. Moreover, the shallow water wave is estimated by applying wind field, design water level considering storm surge height for typhoon Maemi to SWAN model. Under the condition of shallow water wave, obtained by the SWAN model, the wave overtopping rate for the dike in front of Noksan industrial complex is calculated a hydraulic model test. Finally, based on the calculated wave-overtopping rate, the inundation regime for Noksan industrial complex was predicted. And, numerically predicted inundation regimes and depths are compared with results in a field survey, and the results agree fairly well. Therefore, the inundation modelthis study is a useful tool for predicting inundation regime, due to the coastal flood of severe water wave.

• International Journal of Knowledge Content Development & Technology
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• v.14 no.1
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• pp.33-52
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• 2024

This study examined the virtual methods of service delivery being deployed by librarians in private universities in Nigeria. The objective of the study was to analyse the virtual methods of service delivery among librarians and determine the predominant method used among the librarians. Survey research design was adopted for the study. Total enumeration technique was adopted for the study. A population of 181 librarians from 45 private universities in Southern Nigeria were involved. Data were gathered, analysed and presented using frequency counts, percentages, mean and standard deviation. The study found that librarians used different virtual methods of service delivery. Library website 157 (90%) and e-mail 132 (76.3%) were the prominent electronic media used by librarians while Facebook 59 (34%) and Whatsapp 57 (32.9%) were the predominant social media platforms applied for service delivery by librarians. Electronic media were more used for latest publications arrival, as well as library education and document delivery services while social media were more used for reference services and selective dissemination of information. In conclusion, virtual methods of service delivery were deployed by librarians in private universities for service delivery. In comparing the virtual methods, librarians used more of electronic media than social media to deliver services to their users. Therefore, electronic media were predominantly used than social media, many of the virtual methods were found to be underutilised while recommendations were proffered.