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Tungsten-Steel Composites and FGMs Produced by Hot Pressing
Matějíček, Jiří ; Boldyryeva, Hanna ; Brožek, Vlastimil ; Čižmárová, E. ; Pala, Zdeněk
Tungsten-steel composites and FGMs are being developed for potential application in plasma facing components of fusion devices. In this study, uniform composites and graded layers produced from tungsten and steel powders by hot pressing were investigated. Formation of dense composites with uniform distribution and good bonding of the phases was observed. A thin layer of intermetallic phase Fe7W6 formed at the interfaces. Thermal and mechanical properties of the composites in the as-produced and annealed state were characterized.
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Breathing Apparatus equipment in the Units of the Fire Rescue Service of the South Bohemia Region
SOKOL, Karel
The Fire Rescue Service of the Czech Republic is one of the fundamental components of the Integrated Rescue System. Its overall development and modern equipment allows for a very effective way to provide assistance in all types of emergencies. The breathing apparatus equipment is one of the many parts of the common personal protective equipment that allows firefighters to remain within even a stifling environment. The aim of this thesis was to make a full analysis of the numbers and the range of age in use of these kinds of breathing apparatuses and cylinders, which belong to the units of the equipment in the Fire Rescue Service of the South Bohemia Region. Furthermore, I have made a comparison between the two basic types of air breathing apparatuses that are being used, in terms of the protection period, which have been provided to the users (carriers). The participants of this inquiry were members of the FRS of the South Bohemia Region, which include the separation of chemical and technical services into the various local departments. I have received the data from twenty different fire stations in total. In the questionnaire which was given, I collected the data from the respondents, according to their age and added the number of different types of breathing apparatus and cylinders and period or time of use to this study. The data was collected during February and March 2010. Hypothesis 1: the number of pieces of the breathing apparatus equipment in the South Bohemia Fire Rescue units is sufficient; this was confirmed. The result has been compared with the numerical data collected from the indicated positions in the current legislation set to 1.7 times of the number of the members serving in one inning. Hypothesis 2: that these breathing apparatuses meet the requirements of all of the current legislation; this has not been confirmed. The result shows a comparison of the technical parameters of the instruments and technical conditions, as reported by the Interior Ministry decree No. 255/1999 Coll. as amended, regarding the technical conditions kind of fire. The results will be used to establish the financial balance sheet and the planned purchases of the pressurized breathing apparatus equipment and the used variations of the composite cylinders.
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Preparation and properties of MgO-Ni(Fe) nanocrystalline composite
Schneeweiss, Oldřich ; Pizúrová, Naděžda ; Jirásková, Yvonna ; Žák, Tomáš ; Bezdička, Petr ; Večerníková, Eva
We have prepared MgO-Ni(Fe) nanocrystalline composites by controlled heat treatment of compacted spark synthesized nanocrystalline powders. Besides particle sizes and their chemical compositions, influence of interaction with surrounding atmosphere and adsorbed gases on phase composition and magnetic properties were investigated. Mössbauer spectroscopy, x-ray diffraction and TEM were used for phase analysis. Thermomagnetic curves and DTA/TG measurements were applied for detection of changes in structure and phase composition during heat treatments. The simultaneous gas analysis using mass spectroscopy by heating yielded information on adsorbed and dissolved gases and their reactions with the nanoparticles.
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