• Title/Summary/Keyword: Natural draft

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Derivation of Threshold Values for Groundwater in Romania, in order to Distinguish Point & Diffuse Pollution from Natural Background Levels

  • Radu, E.;Balaet, Ruxandra;Vliegenthart, F.;Schipper, P.
    • Environmental Engineering Research
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    • v.15 no.2
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    • pp.85-91
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    • 2010
  • Romania aims to adopt and implement the European Union's legislation, also including that for the field of water management. Like other countries, groundwater in Romania is locally polluted from point sources, such as leaking landfills, as well as from diffuse pollution sources, include fertilizers, pesticides and leakages from sewers, in urbanized areas. Diffuse pollution can also occur indirectly, by over-exploitation of groundwater wells, resulting in salt water intrusion, as well as from mining and exploitation of mineral aggregates. Romania has quite an intensive monitoring scheme to measure groundwater quality in phreatic and confined aquifers. The purpose of the work resumed in this paper was to derive natural background levels (NBL) for groundwater in order to distinguish the natural elevated concentrations of some substances (natural phenomena) from point and diffuse pollution (anthropogenic phenomena). Based on these NBLs, threshold values (TV) for groundwater will be set according to the requirements of the European Water Framework Directive and the related Groundwater Directive. This paper describes the results of a study for the derivation of NBL and TV in a pilot Groundwater Body. Also, the process and draft results for extrapolating this work for all Romanian groundwater bodies is explained, as well as points for future consideration with respect to monitoring and management.

The Issues and Characteristics of the Preliminary Draft Convention on International Contracts Concluded or Evidenced by Data Message (전자계약에 관한 국제협약 예비초안의 논점과 특징에 관한 고찰)

  • Choi, Seok-Beom;Park, Jong-Suk
    • International Commerce and Information Review
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    • v.5 no.1
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    • pp.85-100
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    • 2003
  • Legal rules applying to the commerce and international commerce in particular contracts, proper law, jurisdiction and so on, have improved with time and experience. Engaging in e-commerce on the World Wide Web may expose the company to the risk of being sued in any foreign country where Internet user can establish a legal claim. The modem law of contracts is highly sophisticated and difficult to understand. With contracts created in cyberspace, the basic rules are no difference that we can find. However, there are situations in e-commerce that are altogether new and to which the existing rules cannot apply. Here uncertainty and business risk is too high for trading partners to deal with certainty. Therefore existing law must change to e-commerce law so that it provides certainty and enforceability over e-commerce. UNCITRAL Working Group on Electronic Commerce prepared the Preliminary Draft Convention on [International] Contracts Concluded or Evidenced by Data Message from the thirty-ninth session in 2002 which applies to international contracts concluded or evidenced by means of data messages. An electronic contract is concluded when the acceptance of an offer becomes effective, and an offer becomes effective when it is received by the offeree, and an acceptance of an offer becomes effective when the indication of assent is received by the offeror according to this Convention. Electronic contract may be concluded by the interaction of an automated computer system and natural person or by the interaction of automated computer systems, and a contract formed by a natural person that accesses an automated computer system of another person has no legal effect in case the neutral person made a material error in a data message.

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The influence of internal ring beams on the internal pressure for large cooling towers with wind-thermal coupling effect

  • Ke, Shitang;Yu, Wei;Ge, Yaojun;Zhao, in;Cao, Shuyang
    • Wind and Structures
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    • v.28 no.1
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    • pp.1-17
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    • 2019
  • Internal ring beams are primary components of new ring-stiffened cooling towers. In this study, numerical simulation of the internal flow field of a cooling tower with three ring beams under wind-thermal coupling effect is performed. The studied cooling tower is a 220-m super-large hyperbolic indirect natural draft cooling tower that is under construction in China and will be the World's highest cooling tower, the influence of peripheral radiators in operating cooling tower is also considered. Based on the simulation, the three-dimensional effect and distribution pattern of the wind loads on inner surface of the cooling tower is summarized, the average wind pressure distributions on the inner surface before and after the addition of the ring beams are analyzed, and the influence pattern of ring beams on the internal pressure coefficient value is derived. The action mechanisms behind the air flows inside the tower are compared. In addition, the effects of internal ring beams on temperature field characteristics, turbulence kinetic energy distribution, and wind resistance are analyzed. Finally, the internal pressure coefficients are suggested for ring-stiffened cooling towers under wind-thermal coupling effect. The study shows that the influence of internal stiffening ring beams on the internal pressure and flow of cooling towers should not be ignored, and the wind-thermal coupling effect should also be considered in the numerical simulation of cooling tower flow fields. The primary conclusions presented in this paper offer references for determining the internal suction of such ring-stiffened cooling towers.

Load-carrying Capacity Evaluation Method for RC Slab Bridges using the Damage Evaluation Process (손상도 평가 프로세스를 이용한 RC 슬래브 교량의 공용내하력 평가 방안)

  • Lee, Hee-Hyun;Kim, Yuhee;Jeon, Jun-Chang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.5
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    • pp.543-553
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    • 2023
  • This study was conducted to propose a simple method to evaluate the load-carrying capacity of RC slab bridges, which have been most frequently constructed in Korea. A number of RC slab bridges have been considerably deteriorated associate with the long service year. However, since these bridges are not included in the 1st and 2nd class infrastructures due to their short span length, they have been relatively neglected compared to other bridge types in terms of safety management. In the previous theoretical study, a process (draft) was proposed for evaluating the damage of RC slab bridges using the relationship between the displacement response ratio and the stiffness reduction rate derived by the measured displacement and natural frequency. In this paper, to verify the validity of the proposed damage evaluation process (draft), the results to the actual bridges were compared with the safety grade and the Matsui's deterioration index. In addition, to enhance the practical applicability of the existing process (draft), an improved method approximately evaluating the load-carrying capacity using only the measured natural frequency was presented. If an error of 10% of the load-carrying capacity is allowed, it is judged that the proposed damage evaluation process can be appropriately used not only for evaluating the safety of RC slab bridges, but also for determining priorities for their maintenance.

Randomizing Sequences of Finite Length (유한 순서열의 임의화)

  • Huh, Myung-Hoe;Lee, Yong-Goo
    • The Korean Journal of Applied Statistics
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    • v.23 no.1
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    • pp.189-196
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    • 2010
  • It is never an easy task to physically randomize the sequence of cards. For instance, US 1970 draft lottery resulted in a social turmoil since the outcome sequence of 366 birthday numbers showed a significant relationship with the input order (Wikipedia, "Draft Lottery 1969", Retrieved 2009/05/01). We are motivated by Laplace's 1825 book titled Philosophical Essay on Probabilities that says "Suppose that the numbers 1, 2, ..., 100 are placed, according to their natural ordering, in an urn, and suppose further that, after having shaken the urn, to shuffle the numbers, one draws one number. It is clear that if the shuffling has been properly done, each number will have the same chance of being drawn. But if we fear that there are small differences between them depending on the order in which the numbers were put into the urn, we can decrease these differences considerably by placing these numbers in a second urn in the order in which they are drawn from the first urn, and then shaking the second urn to shuffle the numbers. These differences, already imperceptible in the second urn, would be diminished more and more by using a third urn, a fourth urn, &c." (translated by Andrew 1. Dale, 1995, Springer. pp. 35-36). Laplace foresaw what would happen to us in 150 years later, and, even more, suggested the possible tool to handle the problem. But he did omit the detailed arguments for the solution. Thus we would like to write the supplement in modern terms for Laplace in this research note. We formulate the problem with a lottery box model, to which Markov chain theory can be applied. By applying Markov chains repeatedly, one expects the uniform distribution on k states as stationary distribution. Additionally, we show that the probability of even-number of successes in binomial distribution with trials and the success probability $\theta$ approaches to 0.5, as n increases to infinity. Our theory is illustrated to the cases of truncated geometric distribution and the US 1970 draft lottery.

Natural Frequency of 2-Dimensional Cylinders in Heaving; Frequency-Domain Analysis (상하동요하는 2차원 주상체의 고유진동수; 주파수 영역 해석)

  • Song, Je-Ha;Lee, Seung-Joon
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.1
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    • pp.25-33
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    • 2015
  • Following the previous works on the natural frequency of heaving circular cylinder, i.e. Lee and Lee (2013) and Kim and Lee (2013), an investigation of the same spirit on the 2-dimensional cylinder of Lewis form has been conducted. As before, the natural frequency is defined as that corresponding to the local maximum of the MCFR (Modulus of Complex Frequency Response), which is given by the equation of motion in the frequency domain analysis. Hydrodynamic coefficients were found by using the Ursell-Tasai method, and numerical results for them were obtained up to much higher frequencies than before, for which the method was known as numerically unstable in the past. For a wide range of H, the beam-draft ratio, and ${\sigma}$, the sectional area coefficient, including their practical ranges for a ship, results for the natural frequency were computed and presented in this work. Two approximate values for the natural frequency, one proposed by Lee (2008) and another one by the damped harmonic oscillator, were also compared with the current results, and for most cases it was observed that the current result is between the two values. Our numerical results showed that the values of the local maximum of MCFR as well as the natural frequencye increase as ${\sigma}$ increases while H decreases. At present, extension of the present finding to the 3-dimensional ship via the approximate theory like the strip method looks promising.

Proposal on the Creation of a New Space Organization for the Moon and Celestial Bodies' Exploitation (달과 천체 개발을 위한 새로운 우주기구의 창설에 관한 제안)

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
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    • v.29 no.1
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    • pp.161-198
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    • 2014
  • The idea of creating an International Space Exploitation Agency (tentative title: hereinafter referred to ISEA) is only my academic and theoretical opinion. It is necessary for us to establish ISEA as an international organization for the efficient and rapid exploitation of natural resources in the moon and other celestial bodies. The creation of ISEA as a new international organization is based on the Article 11, 5 and Article 18 of the 1979 Moon Agreement. In order to create it as a preliminary procedure, it needs to make the Draft for the Convention on the Establishment an ISEA among the space-faring countries. The main contents of this paper is composed of (1) introduction, (2) joint exploitation of the natural resources (Heliumn-3, etc.) in the moon and ISEA, (3) activities for the exploitation of moon and other celestial bodies by the space-faring powers, (4) legal problems and Solution for the exploitation and mining rights of the natural resources in the moon, mars and celestial bodies, (5) procedure of creating an ISEA, (6) the principal points that need to be included in the draft for the ISEA convention, (7) conclusion. The creation of an ISEA would lead to a strengthening of the cooperation among the States deemed essential by the global community towards joint undertakings in space and would act as a catalyst for the efforts on the exploitation of the natural resources moon, mars, Venus, Mercury and other celestial bodies and allow resources, technology, manpower and finances to be centrally managed in an independent fashion to the benefit of the space-faring countries. It is desirable and necessary for us to create ISEA in order to promote cooperation in the field of space policy, law, science technology and industry etc. among the space-faring countries. The creation of the ISEA will be promoted the international cooperation among the space-faring countries in exploration and exploitations of the natural resources in the moon, Mars, Venus, Mercury and other celestial bodies. Finally, it should be noted that the political drive will be necessary not only to set up the organization ISEA, but also study a subsequent measures. It is also necessary for us to create the ISEA in order to develop the space industry, to strengthen friendly relations and to promote research cooperation among the space-faring countries based on the new ideology and creative ideas. If the heads (president or prime minister) of the space super-powers including the UNCOPUOS will be agreed to establish ISEA at a summit conference, 1 believe that it is possible to establish an ISEA in the near future.

A Study on The Performance of Ventilation and Maintaining Thermal Environment for a Combined Type Diffuser (급·배기 일체형 디퓨저의 환기 및 온열환경 유지성능에 대한 연구)

  • Lim, Seok-Young;Chang, Hyun-Jae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.6
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    • pp.232-241
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    • 2016
  • Installing a ventilator for an apartment house composed of over 100 dwelling units was mandated in 2006 to improve indoor air quality. In the case of mechanical ventilators, the air change rate is kept stable, however 68% of dwellers do not operate their ventilator because of an increased electrical bill and noise. In the case of natural ventilators, the former problems are settled, but there are concerns about cold draught and an increase of heating/cooling cost. Authors are developing a heat recovery type natural ventilator which is a natural ventilator equipped with total heat recovery element, and it is expected that those problems of mechanical ventilator and natural ventilator are resolved by this. The combined type diffuser of this study is an under developed fit to the heat recovery type natural ventilator above. There are no standards to evaluate the performance for this type of diffuser. Due to this issue this study investigated the performance of the ventilation and maintained a thermal environment for the combined type diffuser by comparing it with existing diffusers. The results revealed that the performances of the combined type of diffusers showed different features from the existing ones, and was estimated to be high enough in the performances above.

Development of Nutrition Education Materials for Prevention and Management of Diabetes Mellitus for Older Adults

  • Kim, Kyungwon;Hyunjoo Kang;Yun Ahn;Kim, Se-Hwa;Kim, Hee-Seon
    • Journal of Community Nutrition
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    • v.4 no.2
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    • pp.118-129
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    • 2002
  • Nutrition is important in the management of diabetes mellitus, however, there are few little education materials specifically designed for older adults. The objective of this study was to develop nutrition education materials for prevention and management of diabetes moll for older adults. Materials developed were a booklet and four leaflets. The contents of materials were based on lesson plans. After several revisions of the draft of materials, illustrations and icons appropriate to the contents were designed using illustrator 9.0 and Photoshop 6.0. The booklet was composed of five chapters and 40 pages. The first chapter began with an introduction about diabetes and diabetes management by diet, exercise and medication. The second chapter dealt with ideal body weight, calculation of adequate caloric intake and food exchange list. The third chapter provided information for meal planning and sample menus. The fourth chapter focused on practical tips on nutritional care of diabetes, by providing tips on reducing sugars, fat and salt, and suggestions on eating for special occasions. The fifth chapter dealt with information in case of low blood sugars, exercise and foot care. The topics of the four leaflets were “Diabetes, what is it and care”, “Food exchange list and meal planning”, “Healthy eating for diabetes”, “Special care for diabetes low blood sugars, exercise and foot care” Each leaflet was composed of six sections and was printed in large paper (B4 size) for older adults. The draft of educational materials were re-viewed by four nutrition professionals and finally pilot-tested with ten adults aged 50 and older. The characteristics of the developed materials are as follows, i) messages are delivered using simple, specific information, ⅱ) messages focused on practical applicable tips, ⅲ) various pictures, illustrations and artwork were created and inserted to enhance understanding and interest, ⅳ) sections including risk factor assessment, calculation of ideal body weight and meal planning were designed to induce the user's participation, ⅴ) sample menus and food pictures were inserted in the booklet, vi) characteristics of older adults and transformed characteristics are diversely used to help the user feel familiarity. These materials are self-explanatory and can be used by older adults. These materials also can be used widely in nutrition education at public health centers or senior centers.

Natural User Interface with Self-righting Feature using Gravity (중력에 기반한 자연스러운 사용자 인터페이스)

  • Kim, Seung-Chan;Lim, Jong-Gwan;Bianchi, Andrea;Koo, Seong-Yong;Kwon, Dong-Soo
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.384-389
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    • 2009
  • In general, gestures can be utilized in human-computer interaction area. Even though the acceleration information is most widely used for the detection of user’s intention, it is hard to use the information under the condition of zero or small variations of gesture velocity due to the inherent characteristics of the accelerometer. In this paper, a natural interaction method which does not require excessive gesture acceleration will be described. Taking advantages of the gravity, the system can generate various types of signals. Also, many problems such as initialization and draft error can be solved using restorative uprighting force of the system.

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