• Title/Summary/Keyword: self-starting

Search Result 297, Processing Time 0.027 seconds

The Role of Information Sharing and Social Community in the Evolution of Collaborative Food Networks

  • Bolici, Francesco
    • Agribusiness and Information Management
    • /
    • v.3 no.1
    • /
    • pp.1-10
    • /
    • 2011
  • In this exploratory analysis, we investigate the genesis and the evolution of local food-purchasing networks created and operated by consumers. In details, we describe how collecting and sharing information about food-products can become a central activity for some consumers' communities and how these communities are starting to play an active role in the food supply chain. We define this community-based food-purchasing model as collaborative food network (CFN), and we analytically describe its characteristics and differences with respect to the traditional and industrialized agrifood supply chain models. A collaborative food network community in Italy, known as GAS ("Gruppi di Acquisto Solidale" - "Solidarity Purchasing Groups"), is introduced as an example of our analytical model. We will use this empirical example to present the strengths and weaknesses of the CFN model.

  • PDF

Effects of Sr on the Electrical Properties of PZT Ceramics Prepared by Self-propagating High-temperature Synthesis (자전연소반응법에 의해 제조된 PZT의 전기적 특성에 미치는 Sr의 영향)

  • Yang, Beom-Seok;Shin, Chang-Yun;Won, Chang-Whan
    • Journal of the Korean Ceramic Society
    • /
    • v.45 no.11
    • /
    • pp.713-718
    • /
    • 2008
  • PSZT are selected and SHS are applied to each system. The sintering properties of PSZT powders showed $7.754g/cm^3$ of sintered density and $4{\mu}m$ of grain size at sintering temperature of $1250^{\circ}C$. Curie temperature lowered gradually from $363.6^{\circ}C\;to\;319.2^{\circ}C$ and relative dielectric constants increased rapidly by a quantity of Sr. This remarkable contrast in dielectric properties with powder preparation methods, in this study, was not due to grain size and sintered density but rather a crystallinity and sinterability of synthesized powders, extra-supplied Pb during reaction, mol fraction of rhombohedral phase and purity of starting materials.

Synthesis of Pentasil Zeolites (펜타실 제올라이트의 합성에 관한 연구)

  • Ahn, Byung-Joon;Chon, Hak-Ze
    • Journal of the Korean Chemical Society
    • /
    • v.32 no.2
    • /
    • pp.149-155
    • /
    • 1988
  • Pentasil zeolites, including ZSM-5, ZSM-8, ZSM-11 and silicalites, were synthesized using various organic cations. Synthesis run was carried out in a Parr pressure reactor of $2{\ell}$ capacity and a self-constructed reactor with a magnetic stirring system. The reactant materials used are colloidal silica (Snowtex), sodium aluminate, sodium chloride, TEA, TPA, TBA, Choline and water. The composition of starting materials and the reaction temperature were found to be important factors for the synthesis of uniform pentasil zeolites.

  • PDF

A Basic Study on Position Fixing by Free Gyros (자유자이로를 이용한 위치결정에 관한 기초 연구)

  • Park, Sok-Chu;Jeong, Tae-Gweon
    • Journal of Navigation and Port Research
    • /
    • v.28 no.8
    • /
    • pp.653-657
    • /
    • 2004
  • The authors aim to design further an upgraded and self-contained position fixing system to meet the future commercial requirements. As a first step this paper is to investigate the theoretical structure of position fixing based on the nature of free gyro, in which the tilt angles of the two spin axes at an arbitrary position are measured respectively and the elapsed time with respect to a reference position or starting point is observed And it illustrates some limitations to be expected in this system.

Transient Characteristics of Electromagnet Type Linear Hybrid Motor (전자석형 리니어 하이브리드모터의 과도특성 해석)

  • Jeon, Hye-Jeong;Jeon, Woo-Jin;Lee, Ju;Kamiya, Yushi
    • Proceedings of the KIEE Conference
    • /
    • 2000.07b
    • /
    • pp.879-881
    • /
    • 2000
  • This paper treats the electromagnet type linear synchronous motor with induction operation. The proposed motor consists of the primary winding energized by variable frequency supplies and the secondary having an additional solid-conductor besides the field finding. The conductor is useful for not only the self-starting but also the damping effect In the synchronous drive. From the investigation by the experiment and the finite element analysis coupled with both electric circuit and motion equation we verify that the proposed motor is effective for practical use.

  • PDF

Fundamental materials research in view of predicting the performance of concrete structures

  • Breugel, K. van
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.1-12
    • /
    • 2006
  • For advanced civil engineering structures a service life of hundred up to hundred fifty and even two hundred years is sometimes required. The prediction of the performance of concrete structures over such a long period requires accurate and reliable predictive models. Most of the presently used, mostly experience based models don't have the quality and reliability that is required for reliable long-term predictions. The models designers are searching for should be based on an accurate description of the relevant degradation mechanisms. The starting point of such models is a realistic description of the microstructure of the concrete. In this presentation the need and the role of fundamental microstructural models for predicting the performance of concrete structures will be presented. An example will be given of a microstructural model with a proven potential for long-term predictions. Besides this also the role of models in general, i.e. in the whole design and execution process of concrete structures, will be dealt with. Finally recent trends in concrete research will be presented, like the research on self-healing cement-bases systems.

  • PDF

Brightness special Quality change of wireless electrodeless fluorescent lamp by ferrite change (페라이트 변화에 따른 무전극 형광램프의 휘도 특성 변화)

  • Pack, Gwang-Hyoen;Yang, Jong-Kyung;Lee, Jong-Chang;Choi, Yung-Sung;Park, Dae-Hee
    • Proceedings of the KIEE Conference
    • /
    • 2004.11a
    • /
    • pp.171-176
    • /
    • 2004
  • An electric power efficiency of electrodeless fluorescent lamp has big relative propertye of gas in lamp, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. We used magnetic substance that open self-examination material of electrodeless fluorescent lamp antenna. Ferrite that is used in this experiment was Mn-Zn type. Coill turn was changed from 13th to 15th turn to recognize brightness change of lamp by winding number. Optical equipment that used in an experiment was used to measure brightness (LS-100). When an electrodeless fluorescent lamp was made using and T company's PE22, was it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.

  • PDF

A Study on the Analysis of the Magnetic Fields Generated by the operation of Electric Appliances (전기기구의 운전중에 발생되는 자계성분해석에 관한 연구)

  • Lee, Bok-Hee;Park, Hyung-Ki;Chung, Seung-Soo;Paek, Yong-Hyun
    • Proceedings of the KIEE Conference
    • /
    • 1993.07b
    • /
    • pp.575-577
    • /
    • 1993
  • In this study, the reponse characteristic of the time-changing magnetic field measurement system by using the self-integrated magnetic sensor is investigated. The measurement system has the frequency bandwidth of 40[Hz]-50[kHz]. The time-changing magnetic fields generated by the operations of small-size electric machines are investigated. The magnetic field generated by the starting and/or the operation of electric appliances mainly includes the odd harmonics such as the third, the fifth, the seventh, and so on.

  • PDF

Electrochemical Properties of Carbonized Phenol Resin (탄화된 페놀레진의 전기화학적 성질)

  • 김한주;박종은;홍지숙;류부형;박수길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1999.11a
    • /
    • pp.629-632
    • /
    • 1999
  • For replacing Li metal ai Lithium ton Bakery(LIB) system. we used carbon powder material which prepared by pyrolysis of phenol resin as starting material. It became amorphous carbon by pyrolysis through it\`s self condensation by thermal treatment. Amorphous carbon can be doped with Li intercalation and deintercalation because it has wide interlayer. however it has a problem with structural destroy causing weak carbon-carbon bond. So. we used ZnCl$_2$ as the pore-forming agent. This inorganic salt used together with the resin serves not only as the pore-forming agent to form open pores, which grow Into a three-dimensional network structure in the cured material, foul also as the microstructure-controlling agent to form a loose structure dope with bulky dopants. We analyzed SEM in order to find to different of structure. and can calculate distance of interlayer. CV test showed oxidation and reduction

  • PDF

Anodic Aluminum Oxide (AAO) for Nanotechnology Applications

  • Lee, U
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.02a
    • /
    • pp.33-33
    • /
    • 2010
  • Recently, a self-organizing process that occurs during the anodization of aluminum in acidic electrolytes has attracted a vast amount of research attentions, coupled with the ever-increasing demand for the development of effective, inexpensive and technologically simple methods for the synthesis of low-dimensional nanostructures over a macroscopic area overcoming many of the drawbacks of conventional lithographic techniques. In this presentation, recent progress in the fabrication of ordered nanoporous anodic aluminum oxide (AAO), including conventional anodization techniques, newly developed pulse anodization, hard anodization processes, and generic approaches to three-dimensional pore structures with periodically modulated diameters. Discussion will also cover the applications of AAO for the development of structurally well-defined extended arrays of low-dimensional nanostructures, such as nanodots, nanotubes, and nanowires, which could be model systems in investigating a diverse range of research problems in chemistry and physics and also be starting materials in realizing advanced electronic devices.

  • PDF