Biomedical subjects

Mohammad Hossein Keshavarz

Publications and source records attributed to Mohammad Hossein Keshavarz.

18 recordsLinked to original sources

PubMed2006

New method for calculating densities of nitroaromatic explosive compounds.

A new model has been introduced for simple calculation of crystal density of an important class of organic explosives, namely nitroaromatic energetic compounds. This model is based on the fundamental correlation. The introduced procedure has been applied to 60 well-known and new synthesized organic nitroaromatic explosives. The results show that the present method gives comparable prediction respect to well-developed group additivity method for estimation of crystal density of organic explosives. The introduced simple method can be applied to any complex nitroaromatic explosive that contains the elements of carbon, hydrogen, nitrogen and oxygen with no difficulties.

Crystallization↗

PubMed2006

Prediction of shock sensitivity of explosives based on small-scale gap test.

A new method is described to predict shock sensitivity of C(a)H(b)N(c)O(d) explosives without using any experimental data. It can determine shock sensitivity based on small-scale gap test as the pressure required to initiate material pressed to 90%, 95% and 98% of theoretical maximum density. Three essential parameters would be needed in the new scheme which contain a+b/2-d, the existence of alpha-C-H linkage in nitroaromatic compounds or NNO(2) functional group and difference of the number of amino and nitro groups attached to aromatic ring. Predicted shock sensitivities in some well-known explosives have a root mean square (rms) deviation of 3.97, 4.02 and 5.89kbar of experiment to initiate pressure of material pressed to 90%, 95% and 98% of theoretical maximum density, respectively.

Explosions↗

PubMed2006

Quick estimation of heats of detonation of aromatic energetic compounds from structural parameters.

In this paper, a simple procedure is introduced for a quick and reliable estimation of detonation heats of aromatic energetic compounds without considering heats of formation of energetic compounds. This method does not use any experimental or computed data of energetic materials. The methodology assumes that the heat of detonation of an energetic compound with composition of C(a)H(b)N(c)O(d) can be obtained from the number of nitrogens, ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some specific functional groups. There is no need to use any assumed decomposition products to calculate heats of detonation for energetic compounds. Predicted heats of detonation of pure energetic compounds with the product H(2)O in the liquid state for 31 aromatic energetic compounds have a root mean square (rms) of deviation of 0.32 kJ/g from experiment. The new method gives good results with respect to two empirical methods which use measured heats of formation of explosives with two sets of decomposition gases.

Explosive Agents↗

PubMed2006

Prediction of densities of acyclic and cyclic nitramines, nitrate esters and nitroaliphatic compounds for evaluation of their detonation performance.

A novel approach to density prediction by elemental composition is developed for various important classes of explosives. Some correlations based on two different models are introduced for 82 different energetic compounds whose molecules contain functional groups common to C(a)H(b)N(c)O(d) explosives. These include acyclic and cyclic nitramines, nitrate esters and nitroaliphatic compounds. Of the 69 well-known and recently new synthesized organic explosives for which direct comparison could be made with Tarver group additivity method, root mean square (rms) of deviation for 19 acyclic and cyclic nitramines is 2.839 and 3.412 while for 50 nitrate esters and nitroaliphatic explosives is 1.936 and 1.752 for new and Tarver's method, respectively. This method is the simplest procedure for calculating density of energetic compounds which gives good results as compared to well-developed group additivity method for estimation density of organic explosives.

Aniline Compounds↗

PubMed2006

Detonation velocity of pure and mixed CHNO explosives at maximum nominal density.

In this paper, a simple approach is introduced to predict detonation velocity of pure and mixed explosives at maximum nominal density. This technique may be applied to any pure or mixed explosives that contain elements of carbon, hydrogen, nitrogen and oxygen. The new method requires only elemental composition and some specific structural parameters. The introduced correlation can easily be applied for determining maximum expected detonation velocity of any new CHNO explosive without using its crystal density. Calculated detonation velocities by this procedure for both pure and composite explosive formulations show good agreement with respect to measured detonation velocity at maximum nominal density.

Carbon↗

PubMed2006

Determining heats of detonation of non-aromatic energetic compounds without considering their heats of formation.

A new procedure is introduced for calculating heats of detonation of non-aromatic energetic compounds through ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some structural parameters. There is no need to use heats of formation of non-aromatic energetic compounds that are usually needed by the other methods. Moreover, this much simple method does not use any experimental and computed data of energetic materials. Predicted heats of detonation for 28 non-aromatic energetic compounds have a root mean square (rms) of deviation of 0.54 kJ/g from experiment, which show good agreement with respect to measured values. The new method is the simplest procedure for predicting heats of detonation and provides reliable results which are comparable with the other methods.

Carbon↗

PubMed2006

Novel correlation for predicting impact sensitivity of nitroheterocyclic energetic molecules.

A novel correlation is introduced for predicting impact sensitivity of a variety nitroheterocyclic molecular types, such as nitropyridines, nitroimidazoles, nitropyrazoles, nitrofurazanes, nitrotriazoles and nitropyrimidines. This approach is based on elemental composition and two structural parameters of C(a)H(b)N(c)O(d) nitroheterocyclic energetic compounds. The results for mentioned compounds are compared with complex neural networks computations which use compositional and topological descriptors. Root mean square (rms) of deviation of different nitroheterocyclic molecules including nitropyridines, nitroimidazoles, nitropyrazoles, nitrofurazanes, nitrotriazoles and nitropyrimidines are 58 and 71cm for new correlation and neural networks computations methods, respectively.

Explosive Agents↗

PubMed2006

Approximate prediction of melting point of nitramines, nitrate esters, nitrate salts and nitroaliphatics energetic compounds.

A simple new procedure is introduced to predict melting point of selected class of energetic compounds containing nitramines, nitrate esters, nitrate salts and nitroaliphatics energetic compounds. The number of nitrogen and oxygen as well as the number of nitramine group and the contribution of some specific functional groups would be needed in the new method. Energetic compounds should contain at least one of the functional groups including N-NO(2), C-ONO(2) or nonaromatic C-NO(2). Calculated melting point for 33 nitramines, nitrate esters, nitrate salt and nitroaliphatics are compared with experimental data. Predicted melting points have average deviation of 5.4% for these energetic compounds.

Aniline Compounds↗

PubMed2006

Velocity of detonation at any initial density without using heat of formation of explosives.

The simplest method is introduced for reliable estimating the detonation velocity of large class of CHNO explosives based elemental composition and specific structural groups. There is no need to use heat of formation and the other experimental data for calculation of detonation velocity in the new procedure. Only elemental composition and the number of special structural groups without using heat of formation of explosive is sufficient for reliable desk calculation of detonation velocity. The results show good agreement with experimental values with respect to computed results obtained by complex computer code using BKWS and BKWR equations of state. Predicted velocities of detonation have root-mean-square (rms) percent deviation of 2.2, 5.9 and 5.3 from experimental data for new method, BKWS and BKWR equations of state, respectively.

Explosions↗

PubMed2006

Detonation temperature of high explosives from structural parameters.

A new scheme is introduced for calculating detonation temperature of different classes of high explosives. The ratio of oxygen to carbon and hydrogen to oxygen as well as specific structural parameters are the fundamental factors in the new method. An empirical new correlation is used to calculate detonation temperature of energetic compounds without considering heat contents of explosives and detonation products. Calculated detonation temperatures for both pure and explosive formulations show good agreement with respect to measured detonation temperatures and complicated computer code using BKWR and BKWS equations of state. Predicted detonation temperatures have root-mean-square (rms) percent deviation of 4.6, 14.2 and 4.6 from measured values for new method, BKWR and BKWS equations of state, respectively.

Explosive Agents↗

PubMed2006

Determination of performance of non-ideal aluminized explosives.

Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

Explosions↗

PubMed2006

A simple procedure for calculating condensed phase heat of formation of nitroaromatic energetic materials.

A simple procedure has been introduced for calculating solid and liquid heats of formation of nitroaromatic energetic compounds. This model assumes that the heat of formation of a nitroaromatic compound of composition C(a)H(b)N(c)O(d) can be expressed as a new correlation which depends on elemental composition and various structural and special functional group parameters. Condensed phase heats of formation predicted using the method described herein and complicated quantum mechanical computations [B.M. Rice, J. Hare, Thermochem. Acta 384 (2002) 377] have a root mean square (rms) deviation of 5.9 and 11.1 kcal/mol for 19 well-known organic nitroaromatic compounds. Predicted heats of formation for 29 polycyclic nitroaromatic energetic compounds have a rms deviation from experiment of 10.6 kcal/mol. The results show that the present method gives comparable prediction respect to the other methods such as complex quantum mechanical computation.

Algorithms↗

PubMed2006

Theoretical prediction of condensed phase heat of formation of nitramines, nitrate esters, nitroaliphatics and related energetic compounds.

An empirical approach is presented for calculation heats of formation of nitramines, nitrate esters, nitroaliphatics and related energetic compounds which contain at least one of the functional groups including N-NO(2), C-ONO(2) or nonaromatic C-NO(2). This approach is based on elemental composition and various structural and functional group parameters of C(a)H(b)N(c)O(d) energetic compounds. Heat of formation for 78 nitrocompounds including nitramines, nitrate esters, nitroaliphatics and the data obtained is compared with experimental data. Root mean square (rms) of deviation for 19 well known of mentioned energetic compounds are also compared with complex quantum mechanical computations which show 23.8 and 21.3 kJ/mol for new and quantum mechanical methods, respectively. Predicted condensed phase heats of formation for remainder 59 energetic molecules with complex molecular structures have a rms deviation from experiment of 42.3 kJ/mol.

Aniline Compounds↗

PubMed2005

A simple method to assess detonation temperature without using any experimental data and computer code.

Detonation temperature of C(a)H(b)N(c)O(d) explosives can be predicted from a, b, c, d and calculated gas phase heat of formation of explosives without using any assumed detonation products and experimental data. Two new correlations are introduced for calculation of detonation temperature of aromatic and non-aromatic explosive compounds so that it is shown here how simply calculated heat of formation by additivity rule and atomic composition are only necessary data for this simple prediction. Calculated detonation temperatures by the introduced correlations for both pure and explosive formulations show good agreement with respect to measured detonation temperatures and complicated computer codes. The average mean absolute error in detonation temperature is within about 7.0%.

Computers↗

PubMed2005

The simplest method for calculating energy output and Gurney velocity of explosives.

Two correlations are introduced for calculating Gurney velocity as a useful parameter for thermochemical estimation of explosive energy output. For CaHbNcOd explosives, only the chemical composition of high explosive as well as its condensed or estimated gas phase heat of formation, which later is calculated by group additivity rules, is needed for calculating Gurney velocity. The introduced simple correlations in the present work may be applied to any explosive that contains the elements of carbon, hydrogen, nitrogen and oxygen with no difficulties at any loading density. There is no need to use any assumed decomposition reaction in present work. Gurney velocity are calculated for different pure and explosive formulations and compared with measured Gurney velocity at specified loading density. The results show that the agreement is good for present method as compared to previous correlations.

Explosions↗

PubMed2005

Simple empirical method for prediction of impact sensitivity of selected class of explosives.

A new approach is described in this work to predict impact sensitivity of a variety of polynitroaliphatics, polynitroaromatics and the explosives containing N-NO2. This paper introduces some simple correlations for prediction of impact sensitivity of C(a)H(b)N(c)O(d) explosives using a, b, c, d, molecular weight and structure information of the explosive. The new correlations are applied to test different polynitroaromatics, benzofuroxans and nitramines. The results are compared with experimental data and some models of complex quantum mechanics computation. Predicted impact sensitivities for 46 explosives have a root mean square (rms) of deviation from experiment of 24 cm, which show good agreement with respect to measured values as compared to five different quantum mechanical models. Impact sensitivities for 58 polynitroaliphatics and related explosives are also calculated, and have a rms deviation from experiment of 40 cm.

Empirical Research↗

PubMed2005

A simple approach for determining detonation velocity of high explosive at any loading density.

A simple empirical relationship is introduced between detonation velocity at any loading density and chemical composition of high explosive as well as its gas phase heat of formation, which is calculated by group additivity rules. The present work may be applied to any explosive that contains the elements of carbon, hydrogen, nitrogen and oxygen with no difficulties. The new correlation can easily be applied for determining detonation velocity of explosives with loading densities less than 1g/cm3 as well as greater than 1g/cm3. Calculated detonation velocities by this procedure for both pure and explosive formulations show good agreement with respect to measured detonation velocity over a wide range of loading density.

Carbon↗

PubMed2005

Simple determination of performance of explosives without using any experimental data.

A simple procedure is introduced by which detonation pressure of CaHbNcOd explosives can be predicted from a, b, c, d and calculated gas phase heat of formation of explosives at any loading density without using any assumed detonation products and experimental data. It is shown here that the loading density, simply calculated heat of formation by additivity rule and atomic composition can be integrated into an empirical formula for predicting the detonation pressure of proposed explosives. Calculated detonation pressures by the introduced method for both pure and explosive formulations show good agreement with respect to measured detonation pressure over a wide range of loading density. The deviations are within about experimental errors.

Explosions↗