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Enhancement of Dewaterability of Sewage Sludge by Ultrasonification and Electric Field Treatment (초음파와 전기장 처리에 의한 하수슬러지 탈수성 향상)

  • Mo, Woojong;Han, Jisun;Ahn, Changmin;Yoon, Soonuk;Seok, Heejung;Kim, Changgyun
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.1
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    • pp.23-30
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    • 2013
  • The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

Chemical Devulcanization for the Recycling of Rubber Powder of Waste Tires and Mechanical Properties (폐타이어 고무분말 재활용을 위한 화학적 탈황과 기계적 물성 평가)

  • An, Ju-Young;Park, Jong-Moon;Bang, Daesuk;Kim, Bong-seok;Oh, Myung-Hoon
    • Resources Recycling
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    • v.24 no.3
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    • pp.59-65
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    • 2015
  • Recycling of vulcanized rubber products is a serious problem in the world. A quantity of generated waste tires becomes much more and more because of increasing demands on automobiles, resulted in the cause of serious secondary pollution by sulfur component that is crosslinked to incineration or landfill. In addition, crosslinked surfur is used to interfere with the binding of the raw material rubber. In this study, we analyzed the degree of devulcanization by the chemical devulcanization. Devulcanization ratio of the samples were systematically analysed by variables such as time and temperature. In addition, the effect of swelling method as a pre-treatment process was also measured. A rubber specimen was deepened in a organic 2-buthanol solutions during various times of 1 ~ 5 hrs at 100, 150, $200^{\circ}C$ respectively, then to calculate the crosslink density and the number average molecular weight by using a parallel expansion process, which showed devulcanization degree of analyzed samples quantitatively. Also, the mechanical properties were measured with the samples prepared by using a hot press.

Study on the Realities in Seoul Subway Crimes: Criminal Psychology (서울지하철 범죄 실태에 대한 범죄심리학적 연구)

  • Rim, Sang-Gon
    • Korean Security Journal
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    • no.7
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    • pp.233-285
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    • 2004
  • ‘Defined legally as a violation of law' (Sutherland, E. H. Principles of Criminology, Lippincott, Chicago, 1939) Crime within the group is essentially and primarily antisocial in that the criminal who is welfare of his group acts instead against it and breaks the principles of social solidarity not merely by not doing what these principles prescribe, but by doing something exactly opposites. Any program set up to attack crime and delinquent behavior at their sources. A program of his nature needs the constant and comprehensive collaboration of psychiatrists, social works, educations, lawmakers, and public officials, since crime is a social problem and it should be treated as such. Some crime preventives which should be mentioned are as follows, (1) The insurance that every child will be decently born and that his home life be socially and economically adequate; without socially mature parents the chid is handicapped at the start; thus parental education, integrated with the public school system, should be developed now. (2) A more meaningful educational program which would emphasize ideals of citizenship, moral integrity, and respect for the law and the police. (3) A periodic check made for potential delinquents throughout the public schools and treatment provided if possible; and if not, proper segregation in institutions. (4) Careful attention paid to press, movies, and radio so that crime may no longer appear to be glamorous. This can be done by women's clubs, civic bodies, and other educational groups exerting pressure on the movie syndicates and broadcasting companies to free their productions of the tawdry and lurid characteristics of crime and criminals. Aggression associated with the phallic stage of development, The child ordinarily comprehends sexual intercourse as an aggressive and sadistic act on the part of the male, and specifically on the part of the penis. Evidence that the penis is phantasied as a weapon of violence and destruction come from unconscious productions of normal adults. Limerick, for instance, often refer to the penis as square, or too large, etc., so that intercourse is dangerous and painful for the partner, This may wall be a projection of the male's own fear of coitus. A certain portion of the death-instinct always remains within the person; it is called 'primal sadism' and according to Freud is identical with masochism. 'After the chief part of it(the death instinct) has been directed outwards towards objects, there remains as a residuum within the organism the true erotogenic masochism, which on the one hand becomes a component of the libido and on the other still has the subject itself for a object.' Criminalism, compulsive-neurotic frequent repetition of criminal acts in a compulsive manner. Like most symptoms of the compulsive-neurotic, such antisocial act are closely rated to feelings of hostility and aggression, often against the father. Because these acts are symptomatic, they afford only temporary relief and are therefore repeated. One patient with compulsive-neurotic criminalism was apprehended after breaking into hardware store and stealing money. He later confessed to many similar incidents over the preceding two years. At the same time it was apparent that he stole only for the sake of stealing. He did not need the money he thus obtained and had no special plans for using it.

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The Study on PR Communication with Editorial References on TV Programs (TV 프로그램을 통한 방송사의 자사 홍보활동 연구)

  • Park, Joo-Yeun
    • Korean journal of communication and information
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    • v.31
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    • pp.193-223
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    • 2005
  • As the number of TV channels rapidly grows, the systematic marketing and PR communication of broadcasters are becoming more and more important. To overcome the challenges the sharply increased competition poses, TV stations ave to intensify their strategic marketing efforts. This paper analyses the editorial information aired about the broadcasters and their TV programming as part of the PR efforts made. This present research project is based on one week periods of analysis of TV programming produced and aired by German broadcasters. The program analysis of the five TV channels included in this study revealed a total of 406 cases in which editorial references were made. The result shows no systematic differences between the public and commercial Broadcasters. Channel-specific differences are, however, obvious. PR communication embedded in the regular programs is increasingly tied to media organization and frequently occurs in the reporting of journalistic content. The high number of promotions as part of informational, and even more so as part of magazine and news formats, must be viewed as problematic. Program related branding and the specific tools used to promote the programs provided further evidence regarding the importance of media economic factors. TV channels not only promote their own programs, but also those of affiliated stations, and the increasing influence of economic considerations will have long-range consequences on the variety and quality of the journalistic output. The study furthermore revealed that TV channels utilize program promotion at any time of the day.

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Preparation and Characteristics of Konjac Noodle-added Mugwort (쑥을 첨가한 곤약국수의 제조 및 특성)

  • Kim, Seog-Ji
    • Journal of the East Asian Society of Dietary Life
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    • v.23 no.5
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    • pp.613-619
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    • 2013
  • Konjac gel is known as a low calorie food, because the main component is water. Mugwort has been used for food and medicine for a long time due to itsfunctional property, which contains a lot of vitamins and minerals. Therefore, konjac noodle-added mugwort was prepared. The konjac gel was made by from a centrifuge after adding water, alkali and mugwort power in konjac flour. The centrifuge was used to remove air in the gel. After centrifuging by heating the gel in boiling water for one hour, konjac noodle was made by pressing using a flat heating press. The results are as follows. In the drying process of mugwort freeze drying after blanching in 1% $NaHCO_3$ solution is better than other drying methods. The physical properties (hardness, elasticity, cohesiveness, gumminess) of konjac gel were measured with a Rheometer. The optimum processing conditions were decided by these measured values. The optimum condition of making konjac gel is 9% concentration of konjac flour, a ph of 12.0, $Na_3PO_4$ coagulant and 1.5% concentration of mugwort power in konjac flour.

Review of 24th Seoul IAPD Congress (제 24회 서울 세계소아치과학회 개관(槪觀))

  • Lee, Sangho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.41 no.1
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    • pp.93-118
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    • 2014
  • The Korean Academy of Pediatric Dentistry hosted the $24^{th}$ IAPD Congress in Seoul, Korea on June 12-15, 2013. The main theme of the congress was the "New visions in Pediatric Dentistry" A total number of 1,855 participants, including exhibitors and press from 67 countries, participated in the 24th IAPD Congress. The scientific program consists of 85 invited lectures, 126 oral presentations, and 553 poster presentations. 46 companies and organizations have supported and participated in Seoul IAPD Congress. Overall the congress was a success in terms of high attendance rate from 67 countries over the world. Considering the fact that Korea is located in the far-east, the number of overseas delegates(943) are remarkable. Also it is desirable to have over 100 delegates from developing countries which eventually aim to collaborate worldwide. The scientific program covered a variety of topics and many of the delegates stayed in the session room until the last day of the congress. Although it could have been more beneficial to allot more time for each speaker to discuss further, the program fit the Congress theme "New Visions for Paediatric Dentistry". All social event tickets were sold out early and it attracted participants with interesting program enabling participants to interact and exchange ideas outside of the meeting.

An Evaluation of Exposure to Petroleum Based Dry Cleaning Solvent Used in Commercial Dry Cleaning Shops (석유계 솔벤트를 사용하는 세탁소 작업자의 노출평가)

  • Jeong, Jee Yeon;Yi, Gwang Yong;Lee, Byung kyu;Lee, Naroo;Kim, Bong Yeon;Kim, Kwang Jong
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.15 no.1
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    • pp.19-26
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    • 2005
  • In previous report, we presented that petroleum based solvents used in dry cleaning shop was almost similar to stoddard solvent defined by ACGIH and NIOSH, and the occupational exposure standard of stoddard solvent could be used in total exposure assessment of those solvents. The specific aim of the this study was to evaluate of the solvent exposure used in commercial dry cleaning shops by using occupational exposure standard of stoddard solvent. We conducted first survey of 8 self-employed dry cleaning shops and 5 factory type dry cleaning shops from July to August, and second survey of the same shops from October to November in 2002. The exposure concentration to the solvent during loading and unloading activity of vented dry cleaning machine was 489.2ppm(GM), 270.3ppm(GM), respectively, which was almost excursion limit(500ppm) of ACGIH, and exceed the ceiling limit(312ppm) of NIOSH. The time-weighted average (TWA) worker exposure to the solvent was 21.3ppm(GM) at self-employed shops, 20.7ppm(GM) at factory type shops on first survey, and 31.1ppm(GM), 33.7ppm(GM), respectively on second survey. The TWA exposure concentration of workers with spotting and cleaning machine operating job was 25.4ppm(GM), which was 2.9 times higher than the TWA exposure concentration, 8.8ppm(GM) of press workers. All TWA exposure concentrations was lower than OEL(100ppm) of stoddard solvent. We found that the most heavy exposure process at dry cleaning was loading, unloading process, and the vent of dry cleaning machine was the main emission source for workers exposure to petroleum based solvent.

Glass-alumina Composites Prepared by Melt-infiltration: II. Kinetic Studies (용융침투법으로 제조한 유리-알루미나 복합체: II. Kinetic 연구)

  • Lee, Deuk-Yong;Jang, Joo-Wung;Lee, Myung-Hyun;Lee, Jun-Kwang;Kim, Dae-Joon;Park, Il-Seok
    • Journal of the Korean Ceramic Society
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    • v.39 no.2
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    • pp.145-152
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    • 2002
  • Four commercial alumina powders having different particle size of $0.5{\mu}m,\;2.8{\mu}m,\;12{\mu}m,\;and\;45{\mu}m$ were presintered at 1120$^{\circ}C$ for 2h and then lanthanum aluminosilicate glass was infiltrated at 1100$^{\circ}C$ for 2h in the interval of 0.1h to investigate the penetration kinetic of the glass into the alumina preforms. The infiltration distance is parabolic with respect to time as described by the Washburn equation and the penetration rate constant, K, increases with raising the alumina particle size. The strength of glass-alumina composites increases as the alumina particle size reaches to 2.8${\mu}m$ due to the increase in packing, however, decreases with further increasing the alumina particle size. The fracture toughness of the composites rises with increasing the alumina particle size due to the crack bowing and the interaction between crack and alumina particles.

A Critical Review on the Critical Communication Studies in Korea (한국의 비판언론학에 대한 비판적 성찰: 문화연구와 정치경제학을 중심으로)

  • Cho, Hang-Je
    • Korean journal of communication and information
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    • v.43
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    • pp.7-46
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    • 2008
  • The purpose of this essay explores a critical review of the Korean critical communication studies focused on the problematic of cultural studies and political economy in 2000s. The findings are as follows; The 'consumer turn' or 'audience turn' in new revisionism modelling John Fiske's cultural studies has been interpreted not to complement but to substitute the necessary criticism of the post-authoritarian media establishment of Korea at that time, arising identity crisis of Korean cultural studies as one of the critical camp. On other side, however, some political economy studies close to the unilinear theses of orthodox marxism has been appraised to neglect the complex process and structure of media and cultural production as well. While the press war between the market-dominant dailies and some progressive dailies has given rise to a whole debate as expected in consolidating period of Korean emerging democracy, the conjucturalism as modelled by Hall's 'authoritarian populism' failed to initiate a new theo tical practice in Korea. Finally, this review essay propose the some new research issues that would converge cultural studies and political economy, modernism and postmodernism; citizenship vs 'cultural citizenship'(valuing the private identity and gender) or Habermasian public sphere vs 'cultural public sphere', the culture of production, (modern)citizen/(postmodern)consumer(recently debated in English media policy), 'differentiation' in capitalist production and 'difference' in consumer sovereignty, 21c future vision of public service broadcasting as one of the 20c institutions.

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Seismic safety assessment of eynel highway steel bridge using ambient vibration measurements

  • Altunisik, Ahmet Can;Bayraktar, Alemdar;Ozdemir, Hasan
    • Smart Structures and Systems
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    • v.10 no.2
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    • pp.131-154
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    • 2012
  • In this paper, it is aimed to determine the seismic behaviour of highway bridges by nondestructive testing using ambient vibration measurements. Eynel Highway Bridge which has arch type structural system with a total length of 216 m and located in the Ayvaclk county of Samsun, Turkey is selected as an application. The bridge connects the villages which are separated with Suat U$\breve{g}$urlu Dam Lake. A three dimensional finite element model is first established for a highway bridge using project drawings and an analytical modal analysis is then performed to generate natural frequencies and mode shapes in the three orthogonal directions. The ambient vibration measurements are carried out on the bridge deck under natural excitation such as traffic, human walking and wind loads using Operational Modal Analysis. Sensitive seismic accelerometers are used to collect signals obtained from the experimental tests. To obtain experimental dynamic characteristics, two output-only system identification techniques are employed namely, Enhanced Frequency Domain Decomposition technique in the frequency domain and Stochastic Subspace Identification technique in time domain. Analytical and experimental dynamic characteristic are compared with each other and finite element model of the bridge is updated by changing of boundary conditions to reduce the differences between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of highway bridges. After finite element model updating, maximum differences between the natural frequencies are reduced averagely from 23% to 3%. The updated finite element model reflects the dynamic characteristics of the bridge better, and it can be used to predict the dynamic response under complex external forces. It is also helpful for further damage identification and health condition monitoring. Analytical model of the bridge before and after model updating is analyzed using 1992 Erzincan earthquake record to determine the seismic behaviour. It can be seen from the analysis results that displacements increase by the height of bridge columns and along to middle point of the deck and main arches. Bending moments have an increasing trend along to first and last 50 m and have a decreasing trend long to the middle of the main arches.