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Wyszukujesz frazę "Zeman, M." wg kryterium: Autor


Wyświetlanie 1-9 z 9
Tytuł:
Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel
Autorzy:
Węglowski, M. St.
Zeman, M.
Grocholewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/355256.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultra-high strength steel
weldability
Weldox 1300 steel
physical simulation
Opis:
In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 127-132
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmiany geochemiczne kwaśnych odcieków z kopalni Smolnik (Karpaty Zachodnie, Słowacja
Geochemical evolution of acid mine drainage quality at the locality of Smolnik (Western Carpathians, Slovakia)
Autorzy:
Slesarova, A.
Zeman, J.
Kusnierova, M.
Powiązania:
https://bibliotekanauki.pl/articles/319429.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
kwaśny odciek z kopalni
metale ciężkie
trendy zmian
procesy geochemiczne
acid mine drainage
heavy metals
evolution trend
geochemical processes
Opis:
Kwaśne odcieki z kopalń (AMD) są zaliczane do największych zagrożeń środowiskowych. Powstają one w wyniku naturalnego utleniania minerałów siarczkowych - głównie pirytu - narażonych na równoczesne działanie wody i tlenu, i negatywnie wpływają na ekologię środowiska wodnego. Artykuł przedstawia wyniki monitoringu odwadniania kopalni Smolnik od roku 1986 do 2004 oraz analizę zjawisk geochemicznych występujących w trakcie odwadniania.
Acid mine drainage is considered among the worst environmental problems associated with mining activity. AMD originates as a result of the natural oxidation of sulphide minerals, mainly pyrite when exposed to the combined action of water and oxygen and negative affects the whole ecology of aquatic environment. The article presents the results of the monitoring of acid mine drainage quality's evolution at the locality of Smolnik from year 1986 till 2004 and the assumed geochemical processes occurred within the generation of acid mine drainage.
Źródło:
Inżynieria Mineralna; 2006, R. 7, nr 2, 2; 37-41
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent Advances in the Study of the Initiation of Nitramines by Impact Using Their 15N NMR Chemical Shifts
Autorzy:
Jungová, M.
Zeman, S.
Yan, Q.-L.
Powiązania:
https://bibliotekanauki.pl/articles/358278.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
impact sensitivity
initiation
15N NMR chemical shifts
Opis:
The relationship between the 15N NMR chemical shifts of aza nitrogen atoms in twelve nitramines and the impact sensitivity of these compounds, expressed as the drop energy, Edr, has been analyzed from the point of view of recently published findings. This relationship appears to be the best method for identifying the key atoms at the reaction centre of a given molecule. These atoms might be taken as “chemical hot spots”. The absence of any solid state influence on the chemical shifts, which were here determined in solution, does not have a fundamental influence on the reaction centre identification. The relationship discussed here confirms the close molecular structural dependence for drop energies (impact sensitivities) obtained for individual energetic materials (EMs) by means of a standard impact tester (Julius Peters) with the detection of the 50% probability of initiation based on acoustic detection. The dependence of impact sensitivity on specific crystal surfaces, using samples of individual EMs obtained by screening, should be investigated more extensively.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 3; 383-393
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent advances in the study of the initiation of energetic materials rusing characteristics of their thermal decomposition. Part I, Cyclic nitramines
Autorzy:
Zeman, S.
Yan, Q.-L.
Vlček, M.
Powiązania:
https://bibliotekanauki.pl/articles/358411.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
arrhenius parameters
detonation velocity
explosives
initiation
manometric method
nitramines
Opis:
Arrhenius parameters, Ea and log A, of 17 cyclic nitramines, derived from the Russian vacuum manometric method (SMM) and compatible thermoanalytical methods, have been used in this study. The detonation velocity, D, at maximum theoretical crystal density, of the nitramines in this study was taken as a characteristic of their detonation. On the basis of known relationships between their Ea and D2 values (modified Evans-Polanyi-Semenov equation), the specific influence of some physicochemical properties on their thermal decomposition was shown. A new logarithmic relationship was found between the rate constant k, of the unimolecular thermal decomposition of the nitramines studied at 230 °C, and their D values. A fundamental characteristic of this new relationship rests on the equivalency of the primary fission processes in the low-temperature thermal decomposition and on the detonation initiation of the nitramines under study. Both these relationships confirm the problems encountered in the kinetic specification of the thermal decomposition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12hexaazaisowurtzitane (HNIW, CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). These problems, and also the possible influence of the pre-decomposition states on the thermal decomposition of the nitramines studied, are discussed.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 2; 173-189
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relative Explosive Strength and Detonation Characteristics of Some Explosive Mixtures Containing Urea and Peroxides
Autorzy:
Hussein, A. K.
Zeman, S.
Suceska, M.
Jungova, M.
Powiązania:
https://bibliotekanauki.pl/articles/403797.pdf
Data publikacji:
2017
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
urea
hydrogen peroxide
perchlorate
nitrates
ballistic mortar
Explo5
Opis:
Several mixtures, based on urea, urea hydrogen peroxide complex (UHP), triacetone triperoxide (TATP) with some inorganic oxidants were studied by means of ballistics mortar with TNT as a reference standard. The detonation pressure, P, detonation velocity, D, detonation heat, Q, and volume of gaseous product at standard temperature and pressure conditions (STP condition) were calculated by the mean of Explo5 V6.3. The relatively high explosive strength of some samples relative to the TNT charge, focuses on the positive influence of hydrogen peroxide presence in these mixtures, with advantage in the form of its complex with urea (i.e. as UHP). This influence connects with hydroxi-radical in the mixture under its initiation (as the first intermediate of this initiation reaction).
Źródło:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2017, 8, 3 (29); 23-32
2081-5891
Pojawia się w:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Different Polymeric Matrices on the Sensitivity and Performance of Interesting Cyclic Nitramines
Autorzy:
Elbeih, A.
Zeman, S.
Jungova, M.
Akstein, Z.
Powiązania:
https://bibliotekanauki.pl/articles/358359.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
HNIW
BCHMX
RDX
HMX
sensitivity
performance
Opis:
Different polymeric matrices, based on butadiene-styrene rubber, polymethyl-methacrylate and silicone binders, were investigated for their ability to decrease the sensitivity of explosives to different mechanical stimuli. A series of plastic explosives based on four different nitramines, namely RDX (1,3,5-trinitro- 1,3,5-triazacyclohexane), β-HMX (β-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane), BCHMX (bicycloHMX, cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5- d ]imidazole) and ε -HNIW (ε -2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-CL-20), bonded by the selected polymeric matrices were prepared. Sensitivity to impact of all of the plastic explosives prepared as well as of the pure explosives, was measured using the fall hammer test. Sensitivity to friction was determined using the BAM friction test. The performance was studied using the ballistic mortar test and the results were recorded relative to TNT (trinitrotoluene) as reference. By comparing the results of impact and friction sensitivities, it is obvious that the mechanism of transfer of the friction force to the reaction center of the nitramine molecule should be different from that of impact energy transfer. The silicone binder appeared to be the best polymer for decreasing the sensitivity of explosives. The results of the ballistic mortar proved that the performance of the plastic explosives prepared is affected by the type and weight percentage of the binder in each sample.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 2; 131-138
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fortifcation of W/O Emulsions by Demilitarized Explosives. Part I. Use of TNT
Autorzy:
Němec, O.
Jungová, M.
Mareček, R.
Novotný, M.
Zeman, S.
Šelešovský, J.
Powiązania:
https://bibliotekanauki.pl/articles/358504.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
demilitarized explosives
detonation
emulsion
TNT
Opis:
This paper presents a study of the relationship between detonation velocities, D, and relative explosive strength (RS) of fortifed W/O emulsion explosives, on the one hand, and the grain size and quality of the demilitarized TNT used for this fortifcation, on the other. It has been found that demilitarized TNT having a grain size below 400 μm could give acceptable results both in terms of initiation and detonation velocity and the RS values. Demilitarized TNT, however, is not a reliable sensitizer even in a micronized state, and therefore using TNT necessitates simultaneous sensitizing of the fnal W/O explosive with microballoons and it has no signifcantly better infuence on the performance of the resulting explosives. The small-scale cook-off test of such a W/O mixture fortifed by 50% by wt. of TNT has shown that such a mixture is a relatively safe explosive.
Źródło:
Central European Journal of Energetic Materials; 2011, 8, 3; 193-207
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Stability and Detonation Characteristics of Pressed and Elastic Explosives on the Basis of Selected Cyclic Nitramines
Autorzy:
Elbeih, A.
Pachmáň, J.
Zeman, S.
Trzciński, W. A.
Akstein, Z.
Sućeska, M.
Powiązania:
https://bibliotekanauki.pl/articles/358014.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
detonation
C4 matrix
BCHMX
HMX
HNIW
RDX
stability
Viton
Opis:
Bicyclo-HM X (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d] imidazole or BCHM X) was studied as a plastic explosive bonded with the C4 matrix and with Viton A. Also a series of nitramines namely RDX (1,3,5-trinitro-1,3,5=triazinane), HM X (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) and HNIW (ĺ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ĺ-CL-20) were studied for comparison with the same types of binders. The detonation velocity, D, of all prepared mixtures was measured. Their thermal stability was determined using non-isothermal differential thermal analysis (DTA). While the C4 matrix lowers the thermal stability of the resulting explosives, Viton A enhances this stability. Approximate relationships between the peaks of exothermic decomposition and the D values were found. The detonation parameters were also calculated by means of Kamlet & Jacobs method, CHEETAH and improved EXPLO5 code for all the mixtures. From the measured D values and the calculated detonation parameters, it is obvious that the detonation parameters of BCHM X-mixtures are very close to HM X-explosives and better than those of RDX-mixtures. It was found that the C4 matrix reduces the difference between the values of energy of detonation in the studied C4 mixtures. As expected, the pressed HNIW-Viton A mixture has the highest detonation parameters of all of the prepared mixtures.
Źródło:
Central European Journal of Energetic Materials; 2010, 7, 3; 217-232
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concerning the shock sensitivity of cyclic nitramines incorporated into a polyisobutylene matrix
Autorzy:
Pelikán, W.
Zeman, S.
Yan, Q. L.
Erben, M.
Elbeih, A.
Akštein, Z.
Powiązania:
https://bibliotekanauki.pl/articles/358036.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
BCHMX
β-HMX
RDX
ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane
CL-20
gap test
impact
Opis:
Two types of plastic bonded explosives (PBXs) based on ε-2,4,6,8,10,12hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-HNIW, CL-20), and PBXs based on 1,3,5-trinitro-1,3,5-triazinane (RDX), β-1,3,4,7-tetranitro-1,3,5,7-tetrazocane (β-HMX) and cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole (bicycloHMX, BCHMX) were prepared using a polyisobutylene binder with dioctylsebacate (DOS) as plasticizer, i.e. a C4 matrix. One version of the ε-HNIW PBX is a product with reduced sensitivity (RS-ε-HNIW). All these PBXs, referenced respectively as RS-ε-HNIW-C4, ε-HNIW-C4, RDX-C4, HMX-C4 and BCHMX-C4, were tested using the Small Scale Gap Test according to STANAG 4488. The results of the gap test on the PBXs with RDX, β-HMX and BCHMX correspond to the impact sensitivities of the original crystalline nitramines. This is not entirely valid for ε-HNIW. In other words, PBXs with RS-ε-HNIW cannot achieve as low a shock sensitivity as would be expected from the differences obtained from the impact sensitivities between RDX, β-HMX and BCHMX, on the one hand, and RS-εHNIW on the other. It is shown that the morphological stability of RS-ε-HNIW in the C4 matrix is insufficient. However, further development and use of RS-ε-HNIW as a filler of PBXs would seem to be both desirable and beneficial. Despite the relatively high impact sensitivity of crystalline BCHMX, the shock sensitivity of its analogous C4 PBX is already good, and comparable with that of RS-ε-HNIW.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 2; 219-235
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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