• Title/Summary/Keyword: Early Age Concrete

Search Result 585, Processing Time 0.02 seconds

A Consideration on the Electromagnetic Properties of Road Pavement Using Ground Penetrating Radar (GPR) (지표투과레이더(GPR)에 의한 도로포장의 전자기적 특성값 고찰)

  • Rhee, Jiyoung;Shim, Jaewon;Lee, Sangrae;Lee, Kang-Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.40 no.3
    • /
    • pp.285-294
    • /
    • 2020
  • This study investigated the use of Ground Penetrating Radar (GPR) over a two-decade period on public roads, focusing on the electromagnetic characteristics of the pavement dielectrics and attenuation. From the results, a typical range of characteristic value, influencing factors, and a correction method were suggested. The typical dielectrics of asphalt pavements were 4-7, as measured by an air-coupled 1 GHz GPR antenna. The dielectrics of concrete pavements were very large in the early age, but were drastically reduced with ageing. Ten years on, collection was in the range of 6-12. The dielectrics were proportional to the relative humidity (R.H.) of the atmosphere. The effects were reduced to one eighth with an overlay. Attenuation generally increased with thickness of the road layer, and also increased where there was damage. The GPR results could also vary depending on the weather conditions as well as on the characteristics of the GPR equipment, even at the same frequency. Therefore, GPR surveys should be performed on road surfaces without debris on a single, fine day. The reliability of the GPR analysis could be improved by cores and equipment calibration with other non-destructive test surveys.

A Study on the Introduction of Linear Programming Model into the Management of Korean Coastal and Offshore Fisheries (한국 연근해어업의 합리적 관리를 위한 LP모형의 도입방안에 관한 연구)

  • 박장일
    • The Journal of Fisheries Business Administration
    • /
    • v.25 no.1
    • /
    • pp.37-59
    • /
    • 1994
  • Many studies to cope with the present problems of Korean coastal and offshore fisheries has been performed, but these were done partly in necessities and general studies for Korean inshore and offshore fisheries are in early stage. Most of these studies adopted analytical way of approach for each fishery individually and they could not reflect the effect of correlated interaction among fisheries on the several common species/stocks, and thus optimal effort allocation was impossible. To consider general fisheries and optimal effort allocation among competing mixed species, a linear programming (LP) approach is applied in this study and introduced into 16 important inshore and offshore fisheries with 13 constraining species which were chosen by annual yield order. This study is not based on the biological interaction among species (i.e., prey - predator system) but the technological interaction between species and fishing efforts. For the application of LP model in these fisheries, the standardization of fishing efforts through different fishing gears could not be successful and a new way of effort standardization through CPUE for vessel tonnage was originated. Total standardized fishing effort on a particular species i, Ei, is computed as the linear summation of standardized fishing effort generated by each fishery j. That is, (equation omitted) where $f_{j}$ is the total vessel tonnage of fishery j and aij is the coefficients contributing to the standardized fishing effort per ton for species i taken in fishery j. The total fishing effort level on species i due to both directed fishing and by - catch can thus be accounted in the aij's. Optimal effort allocation among the j fisheries may be considered a minimizing problem (minimize $\Sigma$ $f_{j}$), subject to the constraints that standardized fishing effort levels on particular species are maintained at, above, and below certain predefined levels. Fishing effort goals for individual species can be based on various biological and/or economic criteria, i.e., fishing effort level generating maximum sustainable yield and/or maximum economic yield. But in this study the $F_{0.1}$ criteria which was accepted as an approximate level for $F_{mey}$ by Outland and Boerema's (1973) study. The findings of this study are, (1) LP model can be applied to the Korean inshore and offshore fisheries giobally. (2) Through a new way of combining multiple different fisheries' efforts for a particular species together generating standardized fishing effort, Schaefer curve could be applied to the complex system successfully. (3) The results of this study for total reduction scale were mostly the same as those of prior studies, but different much from the individual scales of reduction. This study showed the necessities for exploitation of more concrete parameters to put into consideration of profitability of fisheries and social factors, and this model can be modified according to the actual constraints. Also, considering the age structure of stocks, this model can be developed into better one for better fisheries management.ent.

  • PDF

Evaluation on Mechanical Performance and Chloride Ion Penetration Resistance of On-Site Shotcrete Made with Slurry-Type Accelerator (슬러리형 급결제를 활용한 현장적용 숏크리트의 역학적 성능 및 염해저항성 평가)

  • Kim, Hyun-Wook;Yoo, Yong-Sun;Han, Jin-Kyu;Chung, Chul-Woo
    • Journal of the Korea Institute of Building Construction
    • /
    • v.18 no.6
    • /
    • pp.507-515
    • /
    • 2018
  • The purpose of this research is to develop a slurry-type accelerator that contains various beneficial properties such as reduction of dust generation, lower alkalinity, early age strength development, etc., and uses such slurry type accelerator to produce high performance shotcrete that present excellent resistant against chloride ion penetration. In this work, shotcrete mixtures of 0.44 and 0.338 water-to-binder ratio (w/b) were produced at construction site using slurry-type accelerator. The mechanical properties and chloride ion penetration resistance of such shotcrete (including base concrete) were evaluated. According to the experimental results, the slurry-type accelerator was successfully used to produce both w/b 0.44 and 0.338 shotcretes. The 1 day and 28 day compressive strength of shotcrete were found to be closer to or higher than 10MPa and 40MPa, respectively. The w/b 0.338 shotcrete that used 40% replacement of blast furnace slag showed lower compressive strength than w/b 0.44 shotcrete without any mineral admixture at 1 day. However, the compressive strength with 40% blast furnace slag increased significantly at 28 day. Moreover, there was more than 50% increase in chloride ion penetration resistance with blast furnace slag, showing its strong potential for higher performance shotcrete application.

TONYMOLY Cosmetic Company: A Small but Smart Marketing Player

  • Song, Ji-Hee;Lee, Sungho
    • Asia Marketing Journal
    • /
    • v.15 no.1
    • /
    • pp.169-188
    • /
    • 2013
  • Established in 2006 as the forward integration effort by Taesung Industry, the major cosmetic packaging company, TONYMOLY has phenomenally grown to one of the major cosmetic brand companies in the submarket called, 'one brand-shop' of cosmetic market since 2008, after overcoming the crisis of 'going out of business' in a couple of early years. Within a relatively short period of time, TONYMOLY's performances have dramatically improved in terms of metrics such as growth in sales revenue, the number of stores, the average sales per store, transaction value per customer, the number of monthly transactions, the number of membership-based customers, and overseas sales. In this case study, we have examined TONYMOLY's recent marketing activities which may explain the plausible reasons behind the substantial growth of a small but smart cosmetic company. Above all, the first key success factor of TONYMOLY would be found in its adherence to the clear philosophy of the customer value proposition and/or the differentiated position of TONYMOLY as a brand of providing value. Second, this brand concept of value was first penetrated and welcomed among the foothold customer target group of mid and late teens with appropriate products, while the target groups were later expanded into the age group of twenties along with expansion of relevant products. Third, its differentiation efforts have been concrete and meaningful by utilizing unique ingredients in its product development and marketing efforts, unique fun packaging, and continuously introducing new hit-selling products as well as managing steady-selling products. Fourth, TONYMOLY has been smart enough to use its limited marketing money efficiently and effectively in its marketing communication activities. Viral marketing, PPL, and concentrated media planning and execution turned out to produce effective and efficient market-based performances such as awareness, word-of-mouth, and sales. Lastly, the marketing leadership of CEO and top management, emphasizing communications and interactions, was confirmed in the relationship quality with and trust level of its franchisees and internal employees. These key success factors may explain the recent phenomenal market performances of TONYMOLY. Despite recent successes, the major issues are presented for TONYMOLY to consider for maintaining its sustainable advantages and growth. The first issue concerns TONYMOLY's choice of growth philosophy between product/brand-centric marketing and customer-centric marketing. The second challenging issue relates to how TONYMOLY can cope with 'growing pains' plausibly accompanied with the rapid growth.

  • PDF

Study on the Effect of Bizcool Education Satisfaction to Career Awareness - Focused on the Differences among Students (창업교육(Bizcool) 만족도가 진로인식에 미치는 영향 연구)

  • Moon, Kyoung Mok;Yang, Young Seok;Kim, MyoungSook
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.8 no.4
    • /
    • pp.9-23
    • /
    • 2013
  • 'Entrepreneurship' spread like fashion, then it was a term that is no stranger to the youth. Entrepreneurship education for young people is being activated. Recently conducted many educational institutions, as well 'Bizcool' entrepreneurship education. Performance will be clear that the purpose of education and, where appropriate, external training. Currently operating business through 'Bizcool' homepage, 'Bizcool' budget is concentrated in high school. Entrepreneurship education are made aware of the need to equip the correct career awareness is spreading. Preliminary founder, as well as for students. Students will be more structured training support. And many more will be supported by the budget. Therefore, the present study is to analyze the impact of entrepreneurship education career awareness satisfaction. And try to give elementary school students, middle school students, high school students due to the difference in effective entrepreneurship education and ways to activate. The first result, entrepreneurship education training information satisfaction has a significant impact on the career awareness. Satisfaction of the second result, entrepreneurship education teaching methods have a significant impact on the career awareness. The third result, operating the way entrepreneurship education has a significant impact on the recognition of the career satisfaction. The difference between the fourth result, depending on the satisfaction of the entrepreneurship education, career awareness, depending on the level of education does not represent. This study, the results of entrepreneurship education has a positive impact on the career recognition. And have a positive 'Bizcool' education could help implication. However, did not differ according to the difference in student career awareness. So I think it would need more concrete preparation. Also want to provide entrepreneurship education opportunities to students based on the results of this study a little more evenly. Career awareness for students through entrepreneurship education from an early age who would establish the correct values. And students will have a huge impact on the development of the society. The purpose of this study was a survey of students who participated in the 2012 'Bizcool Camp'. This study derives meaningful results. But will need to be interpreted with caution. Some students are first surveyed who participated in the 2012 'Bizcool Camp'. Therefore, there is a limit to generalize the findings. Second, junior high school students surveyed rate is low. So there are limits to students representing the difference. Third, most survey respondents per participant. Therefore, the study subjects, as there is a limit. This study, the impact of career awareness, youth entrepreneurship education satisfaction were analyzed by student differences. The results of this study, more study will be needed for students.

  • PDF