Autor: Zeman, S. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Evaluation of Oxygen Permeability of Polyethylene Films
Autorzy:: Zeman, S.
Kubík, L.
Tematy:: folia polietylenowa
przepuszczalność tlenu
ściółkowanie
oxygen permeability
polyethylene film
packaging
mulching; Pokaż więcej
Wydawca:: Uniwersytet Warmińsko-Mazurski w Olsztynie
Powiązania:: https://bibliotekanauki.pl/articles/298114.pdf Link otwiera się w nowym oknie
Opis:: The paper dealt with the evaluation of the oxygen permeability of the polyethylene films applied in the mulching and food packaging. The construction of the equipment is discussed. The design and the construction of the equipment was realized with applying of the standard EN STN 77 0333.The measurement of the permeability of the oxygen trough the polyethylene Bralen 2-63 with 9% colored concentrate Maxithen HP 533041 - violet film was realized by means of modified method. The values of the permeability Px, 1794.25 cm3*m-2*d-1. (0.1 Mpa)-1 of the oxygen trough the film of the thickness of 50 µm was evaluated. The coefficient of permeability P, 4.2560*10-16 mol*m-1*s-1*Pa-1, coefficient of diffusion D, 4.3999*10-10 m2*s-1 and solubility coefficient of the gas in the film Sp, 9.6735*10-7 mol*m-3*Pa-1 were determined.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Characteristics of Melt Cast Compositions Based on cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d] imidazole (BCHMX)/TNT
Autorzy:: Elbeih, A.
Zeman, S.
Tematy:: nitramines
BCHMX
sensitivity
detonation
brisance; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358268.pdf Link otwiera się w nowym oknie
Opis:: cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5 d]imidazole (BCHMX) is a new bicyclic nitramine which has been prepared using a two-stage synthetic method. In this work, a new melt cast composition based on BCHMX/TNT (60/40 by wt.) was prepared. For comparison purposes, Composition B based on RDX (1,3,5-trinitro1,3,5-triazacyclohexane)/TNT (60/40 by wt.), and HMX (1,3,5,7-tetranitro-1,3,5,7tetraazacyclooctane)/TNT (60/40 by wt.) were also studied. Impact and friction sensitivities of these compositions and of the individual explosives were determined. The detonation velocities were measured experimentally. The performance of the compositions prepared was studied by measuring the brisance using the Kast method. The detonation parameters of the compositions and the individual explosives were calculated using the EXPLO5 thermodynamic code. The results show that mixing these nitramines with TNT decreases their sensitivities. BCHMX/TNT is more sensitive to impact and friction than Composition B while it has higher detonation parameters, at the same level as HMX/TNT. In comparison, BCHMX/TNT has the highest relative brisance of the compositions studied. It is postulated that the higher performance characteristics of BCHMX and compositions based on it, in comparison with those of HMX, are due to a higher positive heat of formation for this nitramine.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Path to ε-HNIW with Reduced Impact Sensitivity
Autorzy:: Elbeih, A.
Husarova, A.
Zeman, S.
Tematy:: HNIW
crystallization
thermal stability
impact sensitivity
SEM; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358508.pdf Link otwiera się w nowym oknie
Opis:: New purification method was applied to obtain epsilon HNIW (ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, ε-HNIW) which has low impact sensitivity. The method is based on removing the impurities from a solution of alpha HNIW (ε-HNIW) by a chemical reaction to obtain pure epsilon form. For comparison, selected different published methods for recrystallization of HNIW to obtain the epsilon form were studied. All the selected methods are based on solvent-antisolvent technique. The optimum parameters, such as type of solvent and anti-solvent, volume ratio of solvent to anti-solvent, rate of addition, speed of stirring, etc., were applied to enhance the crystal size and shape of ε-HNIW. Checking the polymorphs of the obtained HNIW was done by Fourier transform infrared spectroscopy (FTIR). The thermal stability of the prepared samples was studied by using differential thermal analysis technique (DTA). Qualitative analysis of the crystal size and shape was done using scanning electron microscope (SEM) devise. Quantitative measurement of the crystals sizes for the studied samples was determined by Laser scattering particle size distribution analyzer. Impact sensitivity was measured by falling hammer test. The results indicate that all the applied methods of recrystallization give ε-HNIW. The impact sensitivity of HNIW decreases by obtaining small particles with regular shape. All the used published methods produce ε-HNIW with higher impact sensitivity than other nitramines. While the obtained crystals from the new method has regular smooth surface, with small particle size and its impact sensitivity is lower than RDX and HMX.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Effect of polar plasticizers on the characteristics of selected cyclic nitramines
Autorzy:: Elbeih, A.
Zeman, S.
Pachman, J.
Tematy:: energetic materials
polymers
sensitivity
combustion
thermal stability; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358627.pdf Link otwiera się w nowym oknie
Opis:: Dioctyl sebacate (DOS) is a plasticizer used with oily material for the softening of polyisobutylene binder (PIB) to form a polymeric matrix. This matrix was used for the preparation of various plastic explosives. The following energetic cyclic nitramines were used as explosive fillers: BCHMX (cis-1,3,4,6- tetranitrooctahydroimidazo [4,5 d]imidazole), ε-HNIW (ε-2,4,6,8,10,12- hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), RDX (1,3,5-trinitro-1,3,5- triazacyclohexane), and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane). For comparison, Fluorel binder was used for the preparation of several plastic bonded explosives (PBXs) based on the same selected explosives. Impact and friction sensitivities of the prepared samples and the pure explosive fillers were measured. The thermal stability was studied using differential thermal analysis (DTA). High performance liquid chromatography (HPLC) was used to detect the presence of BCHMX dissolved in dioctyl sebacate (DOS). The heat of combustion of the prepared samples and of the pure explosive fillers was measured using a bomb calorimetry. The results show that PIB softened by plasticizer (DOS) has a greater positive effect on decreasing the impact sensitivity of the studied pure explosives than Fluorel binder. On the other hand, the plasticizer acts as a solvent for the energetic materials and decreases the decomposition temperature of these plastic explosives.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

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.
Tematy:: impact sensitivity
initiation
15N NMR chemical shifts; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358278.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Recent Advances in the Study of the Initiation of Energetic Materials Using the Characteristics of Their Thermal Decomposition Part II. Using Simple Differential Thermal Analysis
Autorzy:: Zeman, S.
Yan, Q.-L.
Elbeih, A.
Tematy:: activation energy
detonation velocity
DTA
explosives
initiation
nitramines
PBX
thermal decomposition; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358712.pdf Link otwiera się w nowym oknie
Opis:: Simple Differential Thermal Analysis (DTA), with evaluation of its output by the Kissinger method, was used in the case of emulsion explosives and, as an advanced application, for several plastic bonded explosives (PBXs). In both of these kinds of explosive the square of their detonation velocities, D2, is used as their performance characteristic. A relationship between the slope of the Kissinger equation, EaT-1, and the D2 values makes it possible to formulate a possible mechanism for the initiation of emulsion explosives. Regarding PBXs, it would seem possible to postulate a change in the detonation chemistry of plastic bonded nitramines, depending on the pressure and temperature in the zone of the detonation wave, particularly in the case of CL-20 fillers. Binders with aromatic building units in their macromolecular structure seem to be less-favoured in terms of their thermal reactivity and performance than the final PBXs. These findings document the advantages of the above-mentioned application of simple DTA.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Some Relationships Among Thermal Properties, Detonation Parameters and Sensitivity of Nitramine Fillers in Formex Based PBXs
Autorzy:: Yan, Q. L.
Zeman, S.
Elbeih, A.
Tematy:: explosives
PBXs
detonation parameters; Pokaż więcej
Wydawca:: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Powiązania:: https://bibliotekanauki.pl/articles/403903.pdf Link otwiera się w nowym oknie
Opis:: Thermal behavior and decomposition kinetics of formex-bonded on some attractive cyclic nitramines (BCHMX, HMX, RDX and CL-20) were investigated by means of nonisothermal Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). Besides, their detonation parameters have been calculated by EXPLO 5 code. It was found that the effect of formex polymer base on thermal decomposition of HMX is different from other cyclic nitramines, namely, the formex base could increase the activation energy of HMX while decrease that of others. Besides, the logarithm of volume heat of detonation for formex based explosives is linearly dependent on their time constant of initiation. Furthermore, on one hand, except for RDX, the heat of detonation decreases with the increase of activation energy, and the spark energy and impact energy of cyclic nitramine fillers decreases with the increase of the critical temperature of their PBXs. On the other hand, except for HMX, the rate constant of PBXs is linearly dependent on the impact sensitivity of their pure nitramine fillers.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

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.
Tematy:: arrhenius parameters
detonation velocity
explosives
initiation
manometric method
nitramines; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358411.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Replacement of PETN by Bicyclo-HMX in Semtex 10
Autorzy:: Elbeih, A.
Pachman, J.
Zeman, S.
Akstein, Z.
Tematy:: chemical engineering
plastic explosive
detonation characteristics; Pokaż więcej
Wydawca:: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Powiązania:: https://bibliotekanauki.pl/articles/403386.pdf Link otwiera się w nowym oknie
Opis:: Bicyclo-HMX (BCHMX) was studied in the form of a plastic explosive bonded by the plastic matrix of the explosive Semtex 10 and the results were compared with the original Semtex 10 which contains PETN as an explosive filler. The tests included measurements in the sensitivity to impact and friction. The thermal stability was studied using differential thermal analysis (DTA) with the evaluation of the outputs using the Kissinger method. The detonation velocity was measured experimentally and the detonation characteristics were calculated by means of EXPLO 5 code and the Kamlet & Jacobs method. On the basis of mutual comparison of all the obtained results, it was concluded that replacement of PETN by Bicyclo-HMX enhances the friction sensitivity, thermal stability and the detonation parameters of the explosive Semtex 10, while the impact sensitivity is approximately the same. Calculated results of EXPLO 5 code showed good agreement with the experimental detonation velocities.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Contribution to the Synthesis of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane (TEX)
Autorzy:: Jalový, Z.
Matyáš, R.
Klasovitý, D.
Zeman, S.
Tematy:: 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.05,903,11]dodecane
TEX
1,4-diformyl-2,3,5,6-tetrahydroxypiperazine
tertiary amines
insensitive explosives; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358018.pdf Link otwiera się w nowym oknie
Opis:: The influence of the reaction conditions on 4,10-dinitro-2,6,8,12-tetraoxa- 4,10-diazatetracyclo[5.5.0.05,903,11]dodecane (TEX) yield was studied. TEX was prepared by the reaction of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine with glyoxal in nitric acid. The influence of the acidity of reaction mixture and ratios of starting materials on the yield of TEX was examined and synthesis was optimised. The highest yield (37%) was obtained at 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine/nitric acid molar ratio 67 and sulfuric acid/nitric acid molar ratio around 0.15. Starting material 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine was prepared from formamide and glyoxal using triethylamine or other tertiary amines to adjust suitable basicity. The best yield (84%) of 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine was reached at molar ratio triethylamine/formamide equal to 0.1.
Dostawca treści:: Biblioteka Nauki

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