• Title/Summary/Keyword: Secondary Sources

Search Result 451, Processing Time 0.024 seconds

Chemical Leaching of Silver from Diverse Resources (다양한 자원으로부터 은의 화학적 침출)

  • Xing, Weidong;Lee, Manseung
    • Resources Recycling
    • /
    • v.26 no.1
    • /
    • pp.3-10
    • /
    • 2017
  • The special properties of silver are often indispensable in the manufacture of advanced materials. Therefore, it is of importance to develop a process to recover silver which is necessary for the production of advanced materials from diverse resources. In this manuscript, the developed processes for the leaching of silver from diverse resources are reviewed. For this purpose, the advantages and disadvantages of using some inorganic acids (nitric and sulfuric acid) and their mixture with other oxidizing agents (ozone, oxygen, hydrogen peroxide and ferric ion) were investigated. Moreover, the leaching of silver with thiourea and thiosulfate was compared over those by inorganic acids in terms of environmental effect.

Study on High Efficiency Boosting-up Circuit for Renewable Energy Application (신재생에너지용 연계형 인버터의 고효율 승압에 관한 연구)

  • Jung, Tae-Uk;Kim, Ju-Yong;Choi, Se-Kwon;Cho, Jun-Seok;Kho, Hee-Seok
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
    • /
    • 2009.05a
    • /
    • pp.336-339
    • /
    • 2009
  • In this paper, such as battery power or solar energy and fuel cells generated from Renewable energy sources, high voltage to low voltage DC-DC Converter for converting the design of the study. System consists of low voltage ($24{\sim}28$ [VDC]) and Boosts the voltage (270 [VDC]) for a 3 [kW] DC-DC converter and control circuit is configured as, Power switch the ST Tomson's Automotive low voltage high current MOSFET switches STE250NS10S (temperature 250A) was applied to the two parallel. Also, Controller's processor used ATMEGA128, and Gate Drive applies and composed Photo Coupler TLP250. development. Input voltage (24V) and output voltage (270V) for Conversion in the H-bridge converter topology of the circuit output side power and voltage to control the implementation of the Phase shift angle control applied. And, 3kW of power to pass appropriate specification of the secondary side as interpreted by the high frequency transformer, and the experimental production and analysis of the experiment

  • PDF

A Study on the Quasi-3-Dimensional Compressible Flow Calculation by Introduction of Viscous Loss Model in Axial-Flow Compressor (점성 손실모델 도입에 의한 축류 압축기 준 3차원 압축성 유동해석)

  • 조강래;이진호;김주환
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.13 no.5
    • /
    • pp.1044-1051
    • /
    • 1989
  • A numerical calculation is carried out for the analysis of 3-dimensional compressible flow field in axial-flow rotating blades by using finite element method. The calculation of flow in impellers plays a dominant role in the theoretical research and design of turbomachines. Three-dimensional flow fields can be obtained by the quasi-three-dimensional iterative calculation of the flows both on blade-to-blade stream surfaces and hub-to-shroud stream surfaces with the introduction of viscous loss model in order to consider a loss due to viscosity of fluid. In devising the loss model, four primary sources of losses were identified: (1) blade profile loss (2) end wall loss (3) secondary flow loss (4) tip-leakage loss. For the consideration of an axially parabolic distribution of loss, the results of present calcullation are well agreed with the results by experiment, thus the introduction of loss model is proved to be valid.

An Overview of the Microfinance Sector in Bangladesh

  • Mia, Md Aslam
    • Asian Journal of Business Environment
    • /
    • v.7 no.2
    • /
    • pp.31-38
    • /
    • 2017
  • Purpose - While microfinance institutions(MFIs) from Bangladesh, such as Grameen Bank, received worldwide recognition and the Nobel Peace Prize in 2006, however, there is a paucity of research that provided a comprehensive discussion on the characteristics of the microfinance industry. Hence, the aim of this paper is to discuss some important aspects of the microfinance sector in Bangladesh. Research design, data, and methodology - This study used secondary sources of data, such as annual reports of the Microcredit Regulatory Authority (MRA) and the World Bank database in its descriptive analysis. Results - This study found that Bangladesh has made remarkable progress in her socio-economic and economic development in the last few decades. It is also generally perceived that microfinance has placed significant contribution on such socio-economic development. While microfinance observed unprecedented growth domestically, however, the regulatory framework is still rather weak, and a majority of the MFIs are found to be concentrated in the well-off areas (e.g., Dhaka, Chittagong etc.). Conclusions - The findings are significantly important for the parties who are interested to know the microfinance sector in Bangladesh. To some extent, the findings of this study will provide policy implications that may benefit the industry.

Energy Efficient LED Lighting Design to utilize the Sun Light (태양광 활용을 위한 효율적 LED 조명기구 설계 방안)

  • Jeong, Hak-Geun;Han, Soo-Bin;Jang, Cheol-Yong
    • Journal of the Korean Solar Energy Society
    • /
    • v.31 no.2
    • /
    • pp.31-36
    • /
    • 2011
  • LED is expected as an environmentally friendly next generation light source with its good reliability and long lifetime. The light sources for illumination have a variety of applications in the indoor and outdoor, and the variation of optical power and color rendering of the light source limits their applications. Therefore, it is necessary to research the LED lamp and its luminaire to minimize the variation of dynamic characteristics and to improve the color rendering due to that illuminating environment. Daylight is very good light source to human and can be used as primary or a secondary light source with benefits of energy, productivity and health.This paper presents the design method of LED lighting system to improve poor property in terms of CR(color redering) characteristic to use daylight effectively.

Management Accounting in the Era of Digitalization

  • ALAM, Md. Saiful;HOSSAIN, Dewan Mahboob
    • The Journal of Industrial Distribution & Business
    • /
    • v.12 no.11
    • /
    • pp.1-8
    • /
    • 2021
  • Purpose: For the last few decades, human civilization has observed an enormous change due to digitalization. However, question remains whether and how management accounting has been transformed to meet the demand of the digitalization. This paper provides a literary illustration of such transformation in the context of a digitalized world. Research design, data and methodology: This is a conceptual study based on extant literature. Therefore, the secondary sources of materials were used. Materials include literatures published in this domain, archival documents, and other publicly available data. Results: Drawing from literary evidence, the paper first highlights the evolving character of management accounting. Then it illustrates the changing landscape in the milieu of global and institutional settings with a focus in accounting profession. It further demonstrates the digitalization impact in management accounting. Here it also identifies the changing role of management accountants. Conclusions: The paper is critical for the management accounting professionals in identifying the attributes and nature of management accounting in the contemporary world. It also provides a sketch of the potential skillset that management accounting professionals should embrace to tackle the challenges of the new environment.

E-Government Practice, Challenges and Future Prospects in Developing Countries: the Case of Ethiopia

  • Denbu, Meleket Sahlu;Kim, Yun Seon
    • Asia Pacific Journal of Business Review
    • /
    • v.4 no.1
    • /
    • pp.61-77
    • /
    • 2019
  • This article explored the status of E-Government initiative in developing countries by taking the case of Ethiopia. The study had analyzed the practice, challenges and the future prospect of the E-Government initiative in the country. The paper had used both secondary and primary sources of data. In identifying the practice and future prospects of the E-Government imitative, related works in the area were reviewed and appraised. In ascertaining the major challenges, structured and semi-structured interviews were carried out with selected stakeholders from the government office and the private sector. The result of the study had shown that the country had registered a promising progress in E-Government index in the past four years ranking at 157th in the year 2014, which was standing at 172nd in the year 2012. Above all, high- level political commitment and the design of specific actions plans that are linked to the national sustainable development priorities were the key success factors. Nevertheless, there are still enormous challenges that have to be tackled for citizens to drive the benefits arising from the implementation of E-Government initiative. The study had identified limited cross-sectoral connectivity, lack of intra-organizational connectivity, low human resource capacity, language barrier, lack of awareness and absence of appropriate legal and regulatory framework as major challenges. Finally, the study forwarded constructive suggestion that can be adopted in the way forward of the E-Government initiative.

Effect of nitrogen sources and 2, 4-D treatment on indirect regeneration of ginger (Zingiber officinale Rosc.) using leaf base explants

  • Mehaboob, Valiyaparambath Musfir;Faizal, Kunnampalli;Raja, Palusamy;Thiagu, Ganesan;Aslam, Abubakker;Shajahan, Appakan
    • Journal of Plant Biotechnology
    • /
    • v.46 no.1
    • /
    • pp.17-21
    • /
    • 2019
  • Ginger is an important monocotyledonous plant belonging to the family Zingiberaceae. The objective of this study was to investigate the regeneration potential of ginger using leaf base explants. Auxins such as 2, 4-D and NAA in combination with BA were used for initiation of callus. Different combinations of both ammonium ($NH^{4+}$) and nitrate ($NO^{3-}$) were also studied for efficient callus production. High frequency of white friable calli was observed on modified Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 2, 4-D, 0.5 mg/L NAA and 0.5 mg/L BA. The highest shoot induction (92.33%), shootlets number ($7.33{\pm}0.33$) and length ($88.33{\pm}4.40$) mm were achieved on MS media containing 0.5 mg/L BA. Regenerated shoots were transferred to in vitro rooting media containing 1.0 mg/L IBA. Afterwards, plantlets with well-developed root and shoot system were subjected to a twostep hardening process. 71% of plantlets survived after secondary hardening without any abnormal morphology.

A Study on the Career Development of an Artist: The Case of KAWS (미술가의 경력형성에 관한 연구 - 카우스(KAWS)를 중심으로 -)

  • Lee, Jin Woo
    • Korean Association of Arts Management
    • /
    • no.53
    • /
    • pp.47-69
    • /
    • 2020
  • This paper aims to understand the agents which have an impact upon artists' career development. By critically exploring previous research, this article conceptualizes the roles of intermediaries such as art schools, galleries, critics, and collectors in influencing the careers for artists. The qualitative case study is conducted by selecting KAWS as an intrinsic case. This study collects secondary data about the career trajectory of KAWS by various sources, which are analyzed according to the conceptual framework. The outcome of this research clarifies previous research from a sociological point of view in which highlights the significant importance of the art world's gallery, critics, media and collectors in developing the artist's career. In this paper, more importantly, the public attention to artists is construed as one of the agents influencing the career development of artists.

Report of 21 unrecorded bacterial species in Korea belonging to the phylum Actinobacteria, discovered during the survey in 2020

  • Ham, You Ju;Jeong, Ji Won;Im, Wan-Taek;Kim, Won-Yong;Yoon, Jeong-Hun;Kim, Myung Kyum;Seong, Chi Nam;Kim, Seung Bum
    • Journal of Species Research
    • /
    • v.11 no.1
    • /
    • pp.1-9
    • /
    • 2022
  • The phylum Actinobacteria includes many groups of aerobic, Gram-stain-positive, rod, or filamentous shaped bacteria. Actinobacteria are known for multicellular differentiation in some groups, and also for production of various secondary metabolites such as antibiotics. During a series of extensive surveys of indigenous prokaryotic species diversity in Korea, bacterial strains belonging to Actinobacteria were isolated from various sources of terrestrial environments. A total of 21 bacterial strains, belonging to 10 genera in 8 families, were isolated as unrecorded species in Korea. Among them, 11 were assigned to the family Streptomycetaceae, two species assigned to each of the families Microbacteriaceae, Mycobacteriaceae and Nocardioidaceae, and one species assigned to each of the families Euzebyaceae, Corynebacteriaceae, Micrococcaceae and Intrasporangiaceae. At the genus level, Streptomyces (10 species) was the most abundant, followed by Microbacterium and Mycolicibacterium(2 species each), and one species in each of the genera Corynebacterium, Euzebya, Arthrobacter, Terracoccus, Kribbella, Nocardioides and Yinghuangia. The detailed descriptions of each unrecorded species are provided.