• KLA journal
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• v.49 no.11
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• pp.2-3
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• 2008

• Analytical Science and Technology
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• v.22 no.4
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• pp.285-292
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• 2009

It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.14-27
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• 2020

Differential scanning calorimetry and numerical analysis were performed to estimate the performance degradation and ignition characteristics of the pyrotechnic device due to aging. The reaction kinetics extracted from the calorimetry are implemented into the numerical simulation of the igniter and the pyrotechnic delay, subjected to natural, thermal, and hygrothermal aging conditions. Also, combustion experiments are conducted to confirm that aging due to moisture is a major cause of performance failure of the pyrotechnic device as shown from the present numerical simulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.1-13
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• 2020

The characterization of aging of the pyrotechnic device is conducted thermally, chemically, and spectroscopically. The device is comprised of two parts: (i) igniter composed of Zr and (ii) pyrotechnic delay composed of ZrNi alloy. The thermally induced chemical reaction is identified through Differential Scanning Calorimetry (DSC) and Thermogravimetry Analysis (TGA). The peak deconvolution of the themo-chemical data is used to estimate the enthalpy change of each metallic fuel component. Laser Induced Breakdown Spectroscopy (LIBS) and X-ray Photoelectron Spectroscopy (XPS) are used for chemical species analysis. The decomposition of oxidants by moisture significantly affected the fuel aging, and the formation of oxide film and metal oxide on the fuel surface gave rise to the thermal energy decrease.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.23 no.4
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• pp.161-180
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• 2012

The international standard for the school library suggests that school librarians qualified for librarian and teacher should run the school library. And library assistants should support the teacher librarian to carry out a role as a teacher. Despite the difference of requirements, librarians without teachers' license are under the human resources for school library administration. Furthermore, the job description between the school librarian and librarian is not well-defined in Korea. The different requirements in the library standards and the school library related laws have led to weaken professionalism and social status of librarianship. The condition that teacher librarians are not in the school library have brought the pressure to overcome imperfect functions of the school library and unfairness of educational services. In order to solve these problems, it is necessary to strengthen teacher librarians' qualification system to improve their identity as educational subject specialist librarians. We ought to also build proper foundations of social recognition about librarianship through classifying the types of human resources in the school library into the teacher librarian, library paraprofessional and volunteers. Especially we should hold the job analysis based on administrator, teacher, service, leader, collaboration, and partner.