• 제목/요약/키워드: scale effects

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Simultaneous Removal of Organic Pollutants, Nitrogen, and Phosphorus from Livestock Wastewater by Microbubble-Oxygen in a Single Reactor (단일반응기에서 마이크로버블-산소를 이용한 가축분뇨의 유기오염물질, 질소 및 인의 동시 제거)

  • Jang, Jae Kyung;Jin, Yu Jeong;Kang, Sukwon;Kim, Taeyoung;Paek, Yee;Sung, Je Hoon;Kim, Young Hwa
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.11
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    • pp.599-606
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    • 2017
  • The effects of microbubble-oxygen physicochemical method for the removal of organic pollutants, nitrogen, and phosphorus contained in animal manure were investigated using a laboratory scale single reactor. The characteristics of used livestock manure were $36,894{\pm}5,024mg\;TCOD/L$, $22,031{\pm}2,018mg\;SCOD/L$, $4,150{\pm}35mg\;NH_4-N/L$, and $659{\pm}113mg\;PO_4-P/L$. It was confirmed that the amount of organic pollutants, nitrogen, and phosphorus removal was increased by the use of oxygen rather than air as the gas supplied with the microbubble, and by input of larger oxygen amount. When the oxygen was fed with 600 mL flow rate per minute, TCOD and phosphorus removal were 2.5 times and 5.6 times higher than those of air supplied. As the microbubble-oxygen reaction time was longer, the removal rate of nutrients increased gradually. The removal rates of ammonium and phosphorus reach to $41.03{\pm}0.20%$ and $65.49{\pm}1.39%$, respectively, after 24 hours. When the coagulation treatment method was applied to increase phosphorus removal rate from the effluent of microbubble-oxygen treatment, the phosphorus was removed up to 92.7%. However, the removal rate of organic pollutants (TCOD) was as small as $28.7{\pm}0.2%$ within the first 6 hours, and then the negligible removal of TCOD was recorded. This study suggests that microbubble-oxygen can be applied not only livestock manure but also aeration tank of various wastewater treatment plant, which can reduce the load on the associated unit process and produce stable high-quality effluent.

Association between Satisfaction with Assistive Technology Devices and Psychosocial Impact among Some Mentally or Physically Disabled Children (뇌병변 및 지체 장애아의 보조공학기기 사용 만족도와 심리사회적 영향의 관련성)

  • Jang, Kyoung-Lae;Ryu, So Yeon;Park, Jong;Han, Mi Ah
    • Journal of agricultural medicine and community health
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    • v.42 no.3
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    • pp.132-144
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    • 2017
  • Objectives: The purpose of this study was to identify the association between satisfaction with assistive technology devices and psychosocial impact among some mentally or physically disabled children. Methods: The study subjects were 120 disabled children and their primary caregivers who were using rental assistive technology devices in Gwangju and Jeollanam-Do. Data were collected by structured questionnaire composed of general characteristics of subjects, characteristics related with using assistive devices. Quebec User Evaluation of Satisfaction with assistive Technology 2.0 (QUEST 2.0) and Psychosocial Impact of Assistive Device Scale (PIADS). The statistical analysis were performed by descriptive statistics, t-test, ANOVA and Pearson's correlational analysis. Results: The total mean score for QUEST 2.0 was $4.08{\pm}0.66$ (satisfaction with devices, $4.01{\pm}0.70$; satisfaction with the assistive devices service, $4.14{\pm}0.90$) and the mean of PIADS was $1.00{\pm}0.75$ (ability, $0.99{\pm}0.78$; adaptability, $1.04{\pm}0.86$; self-respect, $0.99{\pm}0.74$). The scores of PIADS was statistically significant difference according to usage time of assistive devices. The PIADS was significantly positive correlated with QUEST 2.0 Conclusions: The mentally or physically disabled children reported that the higher level of satisfaction and the more positive impact of psychosocial aspect with assistive technology devices. It would be necessary to perform further studies for addressing the effects of assistive technology devices.

Density Effects on the Size of 2-1 Korean Pine and 1-1 Jack Pine Nursery Stock (잣나무 2-1 묘(苗)와 방크스소나무 1-1 묘(苗)의 생장(生長)에 미치는 밀도효과(密度効果))

  • Ma, Sang Kyu
    • Journal of Korean Society of Forest Science
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    • v.32 no.1
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    • pp.1-8
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    • 1976
  • One of the most common needle leaf species used in planting in Korea is korean pine (Pinus koraiensis S. et Z.), and jack pine (Pinus banksiana Lamb.) is one of the test species for suitability. The relation of nursery bed density of 2-1 korean pine and 1-1 jack pine was studied at the Kwang Nung Nursery, Central Branch Station of Forest Research Institute, and about 40km north of Seoul. Nursery bed density of 2-1 korean pine, which ranged from 36 to 324 trees per square meters and of 1-1 jack pine, which ranged from 25 to 169 trees per square meters, had a marked effect on caliper, height, dry weight and percent and amount of plantable stock. The soil physical and chemical properties is silt plus clay, 50.55 percent; organic matter, 2.09 percent; total nitrogen, 0.13 percent; available phosphorus, 253.25 ppm; exchangeable potash, 0.46 m.e/100g; and pH, 5.58. As the density of the nursery seedling stand of 2-1 korean pine increases, the average tree height increases (Fig. 1A), but in 1-1 jack pine density do not affect to increase or decrease the average tree height. As the density of nursery bed increases, the average stem caliper (at 2cm above ground line) and dry weight decrease (Fig. 1B), but the decreasing rate is more seriously in 1-1 jack pine than 2-1 korean pine (Fig.5). As increasing the density of nursery bed, the T/R ratio of trees of the test species increase. Also the dry weight of leaf, stem and root parts are decreasing in proportion to the increase of stand density, but the drop rate of jack pine is more rapid than korean pine (table. 1) The patent facts of difference of growth characteristics between 2-1 korean pine and 1-1 jack pine were studied. These facts should be used to select the scale of stand density at the nursery bed or the plantable site. Korean pine is demanded high density, on the other hand in jack pine low density are more suitable to manage the stand density. Stands of comparatively low density had the greatest percentage of high-quality stock, and the stands of high density had less than the high quality trees of low density. An important criterion of the best density is percent and number of high-quality trees produced per square meter of bed area. Stem caliper and stem height of seedling is used in most public nurseries to sort seedling into plantable grades. The stock grade standard has set at 4.5mm caliper and 16cm height of 2-1 korean pine as the minimum desired stem caliper and height. By the result studies, the plantable stock grade standards of 2-1 korean pine used at stem height 16cm and stem caliper 4.5mm from public nurseries should be reformed to stem height 18cm and stem caliper 4.0mm by the growth characteristics and the tree distribution of stem height and caliper of relation to density. For the 2-1 korean pine, best density should be about 160 to 200 trees per square meter according to soil fertility. For the 1-1 jack pine, the suitable standard of plantable stock should be at stem height 25cm and caliper 6mm (at 2cm above ground line) and best density was about 100 to 120 trees.

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Investigation of Requirement and Demand toward for Functional Traditional Hangwa(Korean Cookies) of Tradition (기능성 전통 한과류 요구도 및 수요도 조사)

  • Bok, Hye-Ja;Choi, Soo-Keun
    • Journal of the East Asian Society of Dietary Life
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    • v.18 no.5
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    • pp.692-701
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    • 2008
  • This study was conducted with 150 adults of 20 years or older, all of whom lived in Seoul. The awareness of traditional Hangwa (Korean cookies) was shown to be relatively low, with 2.9 points on average, and the intake of traditional Hangwa for a month was 2.1 times. For the reason that traditional Hangwa couldn't become popular, and the opinion that the reason was because the price is expensive was the highest, at 3.8. The next highest reasons given were because it is difficult to buy, and because it is inconvenient to eat, at 3.0. The traditional Hangwa was shown to enjoy positive awareness as opposed to negative awareness, while the manufacturing sanitation was also recognized to be relatively clean, with 2.6 points assigned to the opinion that it doesn't taste good, and 2.7 points assigned to the opinion that the manufacturing sanitation is unclean. With regard to the excellence of traditional Hangwa, the response that 'our tradition can be handed down' was the most often encountered, with a score of 3.9. The traditional Hangwa was appraised as excellent, with 3.6 points assigned to the opinion 'it suits our body because it is made with our agricultural products' and 3.4% for each opinion 'safe ingredients are used' and 'all ingredients are good for health'. With regard to the level of agreement for the development of functional traditional Hangwa, the positive group was higher than 25.3% of the negative group, with 27.3% for 'agree very much' and 22.0% for 'agree'. When converted into a 5-point scale for the development of functional traditional Hangwa, the group that was positive toward its development was high, with 3.4 points on average. All categories of excellence awareness were correlated with the level of agreement for the development of a functional food product (p<0.001). Consumer awareness toward the addition of traditional Hangwa functionality was generally positive, with 3.3 points or higher on average, and awareness of the aging suppression and diabetes control effects of Hangwa was also high, with 3.5 points. Next were Hangwa for diet, Hangwa for blood pressure control, Hangwa for mineral supple-mentation and vitamin additive-type Hangwa, with 3.4 for each, and Hangwa for health preservation, with 3.3 in order. With regard to the degree of interest toward functional traditional Hangwa for the treatment of diseases, obese patients cited aging suppression, at 3.2, and vitamin additive Hangwa, at 3.0, while Hangwa for dieting was assigned 2.8 points. Patients with high blood pressure, blood circulation, and diabetes were all shown as having a high degree of interest in all items, while evidencing particular interest toward Hangwa for diabetes control and Hangwa for blood pressure control. With regard to intention to purchase while developing functional traditional Hangwa, the group asserting intention to purchase was higher than 60% for all items except for Hangwa for diabetes control (58.7%). The Hangwa for aging suppression was highest, at 68.6%, and shown as having intention to purchase during development in the order of vitamin additive Hangwa at 68.0%, Hangwa for mineral supplementation at 64.6%, each of Hangwa for health preservation and Hangwa for blood pressure control at 62.7%, Hangwa for diet at 62.6% and Hangwa for diabetes control at 58.7%. The considerations during the development of functional traditional Hangwa were in the following order: storage at 4.1 points, taste and level of function at 3.9 points, size at 3.5 points, and packing at 3.4 points.

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Effects of Low Storing Temperature on Respiration Rate and Internal Quality of Fresh Ginseng(Panax ginseng C. A. Meyer) (저온저장 온도가 수삼(Panax ginseng C. A. Meyer)의 호흡률 및 내적 품질에 미치는 영향)

  • Kim, Hee-Su;Hong, Seok-In;Jeong, Moon-Cheol;Kim, Gun-Hee;Kim, Dong-Man
    • Food Science and Preservation
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    • v.18 no.4
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    • pp.467-474
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    • 2011
  • As a serial study to investigate optimum storing temperature of fresh ginseng (Panax ginseng C. A. Meyer), the respiration rate and internal quality of the ginseng was compared during storage for 16 weeks at $-3^{\circ}C$, $-1.5^{\circ}C$ and $0^{\circ}C$. At initial storage period, respiration rate of fresh ginseng was lower at lower temperature, but thereafter it was negligible. Changes in the firmness of fresh ginseng were not significantly different by the storage temperature. The soluble solids content in fresh ginseng was rapidly increased in the early part of storage, and fresh ginseng stored at a lower temperature had a lower content of soluble solids. The iodine-stained color for starch of the main root was rapidly changed for 4 weeks, and L value of the color was the highest in the center, followed by the cambium and the cortex. pH were a little change depending upon the storage temperature, and as a whole, pH was the lowest at $-3^{\circ}C$, followed by $-1.5^{\circ}C$ and $0^{\circ}C$. Although the content of crude saponin tended to somewhat increased as the storage period passed, the effect of storage temperature on changes in the content was not clear. In the sensory evaluation of 'unique flavor' of fresh ginseng using 5 point scale, higher than 3 point was marked for 8 weeks at $-3^{\circ}C$, 14 weeks at $-1.5^{\circ}C$ and 16 weeks at $-0^{\circ}C$ during storage (p < 0.05).

The Effects of Self-Congruity and Functional Congruity on e-WOM: The Moderating Role of Self-Construal in Tourism (중국 관광객의 온라인 구전에 대한 자아일치성과 기능일치성의 효과: 자기해석의 조절효과를 중심으로)

  • Yang, Qin;Lee, Young-Chan
    • The Journal of Information Systems
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    • v.25 no.1
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    • pp.1-23
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    • 2016
  • Purpose Self-congruity deals with the effect of symbolic value-expressive attributes on consumer decision and behavior, which is the theoretical foundation of the "non-utilitarian destination positioning". Functional congruity refers to utilitarian evaluation of a product or service by consumers. In addition, recent years, social network services, especially mobile social network services have created many opportunities for e-WOM communication that enables consumers to share personal consumption related information anywhere at any time. Moreover, self-construal is a hot and popular topic that has been discussed in the field of modem psychology as well as in marketing area. This study aims to examine the moderating effect of self-construal on the relationship between self-congruity, functional congruity and tourists' positive electronic word of mouth (e-WOM). Design/methodology/approach In order to verify the hypotheses, we developed a questionnaire with 32 survey items. We measured all the items on a five-point Likert-type scale. We used Sojump.com to collect questionnaire and gathered 218 responses from whom have visited Korea before. After a pilot test, we analyzed the main survey data by using SPSS 20.0 and AMOS 18.0, and employed structural equation modeling to test the hypotheses. We first estimated the measurement model for its overall fit, reliability and validity through a confirmatory factor analysis and used common method bias test to make sure that whether measures are affected by common-method variance. Then we tested the hypotheses through the structural model and used regression analysis to measure moderating effect of self-construal. Findings The results reveal that the effect of self-congruity on tourists' positive e-WOM is stronger for tourists with an independent self-construal compared with those with interdependent self-construal. Moreover, it shows that the effect of functional congruity on tourists' positive e-WOM becomes salient when tourists' self-construal is primed to be interdependent rather than independent. We expect that the results of this study can provide important implications for academic and practical perspective.

A Study on Culture Studies for the Circuit of Culture of Policy Discourse: Focus on Cultural Representations and Signifying Practices (정책담론의 문화흐름에 대한 문화연구: 문화적 표상과 의미의 실체를 중심으로)

  • Kim, Man-Ki
    • Journal of Digital Convergence
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    • v.9 no.3
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    • pp.69-79
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    • 2011
  • This study is the text discourse of agenda setting through media policy on the three communities. The materials of subjects are the 71 text discourses that appeared in the columns, the special manuscripts, and the comments on the contemporary topics in 33 media. The subjects focuses on the metaphor, metonymy, and binary transposition. This kind of connotation tends to be imploded into people through media, so that it produces hyperreality. This process produces the regulation and strengthens the reality through the circuit of culture. Thus this research tries to develop the theoretical foundation for analysing the text discourse produced by the media. Also it focuses on widening the research scope to study the effects that the circuit of culture provides on the politics, society, and economics. Therefore The first, the objective meanings(denotation)which the referents of the community as T'PALACE, I'PARK, and STARCITY are 'larger scale', 'high and skyscraper', 'the rich people and the plutocrats who have very high academic career' and ' the residence place for the famous stars and successful CEOs', etc. and the subjective meanings, connotations which the referents of the community are 'The first street' transposes '1%' 'their own space' into the characteristics of the wealth of Gangnam district or Korean wealth', the additional significations which the metaphors such as 'the noble community', 'the sample for the high -level residential space', and 'the greed of 1%'. Conclusion, The significations of the symbols became imploded into the population and circulated along with the cultural streams through the media. The referents are recreated and consumed among the other communities such as the named 'PALACE', 'I'PARK', 'STARCITY' in the other areas. This kind of ideology tends to create the myths such as 'the 1% rich people of Gangnam', 'the first street of Korean wealth', and create the regulation such as 'the compound taxes for the real-estates', 'the policy of reducing the taxes for the rich', 'the policy of reducing the taxes for the 1% of the rich'. Also these regulations make the politicians operate new policies and are being utilized as 'slogan' for the politicians.

Methodologies for Enhancing Immersiveness in AR-based Product Design (증강현실 기반 제품 디자인의 몰입감 향상 기법)

  • Ha, Tae-Jin;Kim, Yeong-Mi;Ryu, Je-Ha;Woo, Woon-Tack
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.2 s.314
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    • pp.37-46
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    • 2007
  • In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

Plant Hardiness Zone Mapping Based on a Combined Risk Analysis Using Dormancy Depth Index and Low Temperature Extremes - A Case Study with "Campbell Early" Grapevine - (최저기온과 휴면심도 기반의 동해위험도를 활용한 'Campbell Early' 포도의 내동성 지도 제작)

  • Chung, U-Ran;Kim, Soo-Ock;Yun, Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.10 no.4
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    • pp.121-131
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    • 2008
  • This study was conducted to delineate temporal and spatial patterns of potential risk of cold injury by combining the short-term cold hardiness of Campbell Early grapevine and the IPCC projected climate winter season minimum temperature at a landscape scale. Gridded data sets of daily maximum and minimum temperature with a 270m cell spacing ("High Definition Digital Temperature Map", HD-DTM) were prepared for the current climatological normal year (1971-2000) based on observations at the 56 Korea Meteorological Administration (KMA) stations using a geospatial interpolation scheme for correcting land surface effects (e.g., land use, topography, and elevation). The same procedure was applied to the official temperature projection dataset covering South Korea (under the auspices of the IPCC-SRES A2 and A1B scenarios) for 2071-2100. The dormancy depth model was run with the gridded datasets to estimate the geographical pattern of any changes in the short-term cold hardiness of Campbell Early across South Korea for the current and future normal years (1971-2000 and 2071-2100). We combined this result with the projected mean annual minimum temperature for each period to obtain the potential risk of cold injury. Results showed that both the land areas with the normal cold-hardiness (-150 and below for dormancy depth) and those with the sub-threshold temperature for freezing damage ($-15^{\circ}C$ and below) will decrease in 2071-2100, reducing the freezing risk. Although more land area will encounter less risk in the future, the land area with higher risk (>70%) will expand from 14% at the current normal year to 23 (A1B) ${\sim}5%$ (A2) in the future. Our method can be applied to other deciduous fruit trees for delineating geographical shift of cold-hardiness zone under the projected climate change in the future, thereby providing valuable information for adaptation strategy in fruit industry.

Discounted Cost Model of Condition-Based Maintenance Regarding Cumulative Damage of Armor Units of Rubble-Mound Breakwaters as a Discrete-Time Stochastic Process (경사제 피복재의 누적피해를 이산시간 확률과정으로 고려한 조건기반 유지관리의 할인비용모형)

  • Lee, Cheol-Eung;Park, Dong-Heon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.2
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    • pp.109-120
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    • 2017
  • A discounted cost model for preventive maintenance of armor units of rubble-mound breakwaters is mathematically derived by combining the deterioration model based on a discrete-time stochastic process of shock occurrence with the cost model of renewal process together. The discounted cost model of condition-based maintenance proposed in this paper can take into account the nonlinearity of cumulative damage process as well as the discounting effect of cost. By comparing the present results with the previous other results, the verification is carried out satisfactorily. In addition, it is known from the sensitivity analysis on variables related to the model that the more often preventive maintenance should be implemented, the more crucial the level of importance of system is. However, the tendency is shown in reverse as the interest rate is increased. Meanwhile, the present model has been applied to the armor units of rubble-mound breakwaters. The parameters of damage intensity function have been estimated through the time-dependent prediction of the expected cumulative damage level obtained from the sample path method. In particular, it is confirmed that the shock occurrences can be considered to be a discrete-time stochastic process by investigating the effects of uncertainty of the shock occurrences on the expected cumulative damage level with homogeneous Poisson process and doubly stochastic Poisson process that are the continuous-time stochastic processes. It can be also seen that the stochastic process of cumulative damage would depend directly on the design conditions, thus the preventive maintenance would be varied due to those. Finally, the optimal periods and scale for the preventive maintenance of armor units of rubble-mound breakwaters can be quantitatively determined with the failure limits, the levels of importance of structure, and the interest rates.