Magnesium - an important component of high-energy compositions

Magnesium is a widely used component in high-energy compositions. Mixtures containing this metal can be found in show and military pyrotechnics, rocket propellants and various explosive masses. Magnesium containing compositions have high combustion temperature, which allows one to achieve the desired special effect. Two important stages in designing new high-energy mixtures, i.e. compatibility of substances and optimal composition, were described. The calculations were based on mixtures containing magnesium. In line with the standard STANAG 4147, using differential scanning calorimetry, compatibilities of mixtures of magnesium with octogen (HMX) and magnesium with hekzaazahekzanitroizowurzitane (CL-20) were examined. Magnesium is compatible with these nitroamines. An optimal composition which ensures the maximum combustion temperature and specific impulse was determined using the calculation programme isp2001. The optimum composition of the Mg : HMX composition burns at a lower temperature than the Mg : CL-20 mixture. The combustion temperature was 3493K for the former mixture and 3807K for the latter one. The specific impulse determined for both compositions was 273s. The specific impulse was established for mixtures with different shares of magnesium. The mixture containing in octogen reached the maximum specific impulse at 5% Mg, while the mixture containing CL-20 reached the highest specific impulse at 15% of this metal. The dependence of the specific impulse of rocket propellant containing polybutadiene with terminal hydroxyl groups (HTPB), ammonium perchlorate and magnesium was examined. The maximum value of the impulse increases with a decreasing amount of the binder. When another binder such as for poly(glycidyl azide) (GAP) was used, a reverse relationship was observed. The specific impulse increased with an increased binder content. The influence of various oxidants on the combustion temperature of pyrotechnic mixtures was defined. The highest combustion temperature was achieved for compositions with the magnesium content in the range of 20 to 45%. The effect on combustion temperature of the oxidants polytetrafluoroethylene, potassium chlorate and iron oxide was compared

Magnez - istotny składnik mieszanin wysokoenergetycznych

Magnesium is a widely used component in high-energy compositions. Mixtures containing this metal can be found in show and military pyrotechnics, rocket propellants and various explosive masses. Magnesium containing compositions have high combustion temperature, which allows one to achieve the desired special effect. Two important stages in designing new high-energy mixtures, i.e. compatibility of substances and optimal composition, were described. The calculations were based on mixtures containing magnesium. In line with the standard STANAG 4147, using differential scanning calorimetry, compatibilities of mixtures of magnesium with octogen (HMX) and magnesium with hekzaazahekzanitroizowurzitane (CL-20) were examined. Magnesium is compatible with these nitroamines. An optimal composition which ensures the maximum combustion temperature and specific impulse was determined using the calculation programme isp2001. The optimum composition of the Mg : HMX composition burns at a lower temperature than the Mg : CL-20 mixture. The combustion temperature was 3493K for the former mixture and 3807K for the latter one. The specific impulse determined for both compositions was 273s. The specific impulse was established for mixtures with different shares of magnesium. The mixture containing in octogen reached the maximum specific impulse at 5% Mg, while the mixture containing CL-20 reached the highest specific impulse at 15% of this metal. The dependence of the specific impulse of rocket propellant containing polybutadiene with terminal hydroxyl groups (HTPB), ammonium perchlorate and magnesium was examined. The maximum value of the impulse increases with a decreasing amount of the binder. When another binder such as for poly(glycidyl azide) (GAP) was used, a reverse relationship was observed. The specific impulse increased with an increased binder content. The influence of various oxidants on the combustion temperature of pyrotechnic mixtures was defined. The highest combustion temperature was achieved for compositions with the magnesium content in the range of 20 to 45%. The effect on combustion temperature of the oxidants polytetrafluoroethylene, potassium chlorate and iron oxide was compared

Badanie indeksu krystaliczności drewna dębowego pochodzącego z zabytkowej stolarki budowlanej

The influence of oak wood age on the crystallinity index of cellulose was determined. Antique wood originating from Warsaw woodwork from the middle of the 18th century, the turn of XIXth and 20th century and the middle of the 20th century was analysed. It was reported, using FTIR spectrometry, that the crystallinity index increases with wood age. It is consistent with previous examinations in other papers and shows that the chosen method of crystallinity index analysis is correct.Wraz z upływem czasu stare drewniane okna, drzwi, podłogi podobnie jak i inne elementy stolarki budowlanej nabierają wartości muzealnej i dlatego, jako świadectwo kultury materialnej minionych stuleci powinno zostać zachowane dla przyszłych pokoleń. Za pozostawieniem tych elementów, poza argumentami dotyczącymi wartości zabytkowych i estetycznych, przemawiają właściwości samego drewna, które pomimo upływu czasu często nie ulegają istotnym zmianom, a materiał ten zachowuje pełne funkcje użytkowe. Wobec panujących obecnie niejednoznacznych poglądów na temat skutków długotrwałego starzenia się drewna, istnieje potrzeba podejmowania możliwie wielostronnych badań zmierzających do określenia właściwości zabytkowego drewna. Celem niniejszych badań było określenie indeksu krystaliczności celulozy w drewnie pochodzącym z zabytkowej warszawskiej stolarki budowlanej z połowy 18, przełomu 19 i 20 wieku, a także z połowy 20 wieku w porównaniu do drewna pozyskanego współcześnie. Analizę stopnia krystaliczności celulozy przeprowadzono metodą spektrometrii w podczerwieni FTIR przy użyciu modelu Nicolet 6700, Thermo Fisher Scientific Inc. Wyniki przeprowadzonych badań pozwalają stwierdzić, że w zabytkowym drewnie, w porównaniu do drewna pozyskanego współcześnie, następuje zmiana indeksu krystaliczności celulozy. Wielkość zmian uzależniona jest od wieku drewna. Największym indeksem krystaliczności celulozy charakteryzuje się drewno elementów stolarki budowlanej z 18 wieku, a najmniejszą różnicę wykazało drewno pochodzące z zabytkowych elementów z połowy 20 wieku. Obserwacje te potwierdzają z fachowej literatury, co świadczy także na korzyść wybranej metody określania indeksu krystaliczności