Showing 7 results for mahyari
Zahra Khodadadipour, Seyed Ghorban Hosseini, Mojtaba Mahyari, Javad Mohebbi,
Volume 13, Issue 3 (9-2018)
Abstract
Nanoparticles (NPs) tend to agglomerate consequently their catalytic activities decrease during propellant operation. Therefore, loading the nanoparticles onto the support is a general method to prevent the agglomeration and maintain the catalytic activities of the nanoparticles. Three dimensional (3D) graphene has high surface area and porous structur. Furthermore,, 3D-graphene is an efficient support to grow and anchor NPs with high loading and better dispersity. In this study, firstly CuCr2O4 spinel NPs and CuCr2O4@3D-GFs nanocomposite were synthesized. Thenthe the structure and size of the particles were determined by XRD,FESEM and TG. The as-prepared CuCr2O4 NPs and CuCr2O4@3D-GFs nanocomposite were used as a promising catalyst for the thermal decomposition of ammonium perchlorate (AP) and their catalytic performance was investigated by differential scanning calorimetry and thermal gravimetric analysis (DSC/TGA). Thermal decomposition of AP in the presence 4 wt % CuCr2O4 NPs and 2 and 4 wt % CuCr2O4@3D-GFs nanocomposite prepared by solvent-antisolvent method showed that two exothermic peaks of AP merges into one peak and high-temperature decomposition appeared at 348, 332 and 321°C, respectively.
Soodabeh Morovatipoor, Fathollahi, Seyed Ghorban Hosseini, Mojtaba Mahyari,
Volume 15, Issue 1 (3-2019)
Abstract
The oxidant forms the most part of the propellants, and ammonium perchlorate is the most applicable oxidizer in composite solid propellants. Therefore, its thermal decomposition and immunity properties have been a great effect on the propellants properties. The using of polymeric additives is one of the different methods for improving the thermal and immunological properties of ammonium perchlorate. The types of additive materials are usually selected based on the applicable purpose. In this research, the effects of polymeric additives materials are investigating due to improve the sensitivity, the increase of thermal and chemical stability, and also the prevention of ammonium perchlorate particle agglomeration that have been used up to now.
Manoochehr Fathollahi, Mohsen Goodarzi, Mojtaba Mahyari, Seyed Gorban Hosseni, Mohammad Ali Zarei,
Volume 17, Issue 1 (10-2022)
Abstract
Being non-polar and considerably high electrical resistivity are significant drawbacks of the crystalline paraffin wax used for desensitizing energetic materials. Herein, as a practical approach to improve the wax properties, maleic-anhydride was reacted with paraffin wax in the presence of a free-radical initiator. Then, the reaction success was approved by employing Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) to spot carboxyl groups onto the aliphatic backbone. In addition, the thermal properties of the modified wax were investigated using differential-scanning-calorimetry and thermogravimetry analysis (DSC-TGA). Finally, to estimate the improvement in the wax polarity, an experiment was designed in which HMX coated via a two-step procedure was conducted for DSC and tribocharing tests. The second layer utilized 0.5 w% glyceline as a deep eutectic solvent (DES). In brief, our observation exhibited that the modified wax caused a 50% decrease in charge accumulation compared to the unmodified paraffin. In addition, our experimental outcomes .showed that the modified paraffin exhibited a better distribution over the substrate surface than the unmodified one
Dr Mojtaba Mahyari, Mr Iman Shater Khabazi, Dr Fatemehe Abrishami, Dr Seyed Ghorban Hoseini,
Volume 17, Issue 2 (9-2022)
Abstract
In this paper, the effect of nanocatalytic metal-organic framework based on copper metal and bis-tetrazolamine (CuBTA) ligand functionalized with cobalt (II) oxide nanoparticles on the thermal decomposition behavior of ammonium perchlorate (AP), using differential survey calorimetry (DSC) has been reviewed. First, the metal-organic framework (CuBTA) was synthesized from the raw materials of copper chloride and bistetrazole amine using the solvothermal method and with the help of .... Then, using cobalt (II) nitrate and co-precipitation method, the desired metal-organic framework was functionalized with cobalt (II) oxide nanoparticles. Fuzzy studies were performed with X-ray diffraction pattern (XRD) apparatus, as well as formation investigations using Fourier transform infrared spectroscopy (FT-IR). The results of thermal decomposition of ammonium perchlorate in the presence of metal-organic framework (CuBTA) and nanoparticle functionalized framework showed that 5% by weight of the catalyst, the thermal decomposition temperature of ammonium perchlorate was 34.1 °C and 91.1 °C. Reduced for the metal-organic framework and the metal-organic framework functionalized by nanoparticles, respectively. The combustion enthalpies of 1570 J.g-1 and 1375 J.g-1 were obtained in the same way.
Mohammad Ali Zarei, Dariush Fallah, Mohsen Akbaripour, Seyyed Morteza Razavi, Mojtaba Mahyari, Saeed Tavangar,
Volume 18, Issue 2 (9-2023)
Abstract
Today, vacuum stability test is one of the best methods to investigation the compatibility of different plasticizers and polymers. In this research, the compatibility of polydimethylsiloxane resin with trimethylolethane trinitrate energetic plasticizer was investigated. The applied approaches included vacuum stability test (VST) and glass transition temperature determination using DSC analysis. The acceptance limit of TMETN plasticizer by polydimethylsiloxane resin was determined using retardation and it was found that this polymer can accept the plasticizer at least 20% (w/w). Investigating the glass transition temperature with DSC analysis test showed that polydimethylsiloxane has good compatibility with TMETN plasticizer. The amount of gas released from the sample in standard conditions (VR) in the VST test was calculated as 4.77 cm3, which was within the allowed range and indicates the compatibility of TMETN plasticizer with polydimethylsiloxane.
Dr. Ali Reza Zarei, Mr. Ahmad Bagheri, Dr. Abbas Besharati, Dr. Mojtaba Mahyari,
Volume 19, Issue 4 (12-2024)
Abstract
In this study, the metal-organic framework imidazole-67 (ZIF-67) was used as an effective adsorbent for the preconcentration and separation of explosives. First, the metal-organic framework was synthesized and characterized by SEM, XRD, and FT-IR techniques. Subsequently, the synthesized compound was used as an adsorbent for the separation and preconcentration of nitroaromatic and nitramine explosives based on the solid phase extraction (SPE) technique. Finally, the explosive compounds were measured using high-performance liquid chromatography with UV detection (HPLC-UV). The parameters affecting the adsorption and desorption process, including pH, type of desorption solvents, contact time, adsorbent amount, and adsorption capacity, were investigated and the optimal values were obtained for them. Under optimal conditions, the method is linear for the determination of TNT, 2,4-DNT, RDX and HMX in the range of 0.10-200, 0.5-200, 0.8-200 and 0.10-200 µg L-1, respectively. Also, this technique was used for the extraction of solid phase explosives from water samples and satisfactory results were obtained. The relative recovery (RR) was in the range of 98-104% and the preconcentration factor was 10. Therefore, considering the advantages such as ease of preparation, high efficiency and reusability, the ZIF-67 structure was proposed as an excellent candidate for the adsorption and preconcentration of explosives.
Dr Narges , Dr Mohammadali Zarei, Dr Mojtaba Mahyari, Miss Zeynab Mohammadpour,
Volume 20, Issue 1 (1-2026)
Abstract
This study developed computational models to predict two critical explosive performance metrics—heat of detonation (Q) and detonation velocity (D)—in high-energy metal-organic frameworks (HE-MOFs) containing tetrazole ligands. Applied quantitative structure-property relationship (QSPR) methods and multiple linear regression (MLR) to correlate these detonation properties with molecular descriptors derived from the compounds' topological and spatial features. Two strong models for predicting Q, and D, with a coefficient of determination (R²) of 0.916, 0.819. Average absolute deviations (AAD), and the root mean square deviation (RMSD) of 0.278–0.357 kcal g⁻¹ for Q and 0.482–0.590 km s⁻¹ for D, indicating moderate predictive accuracy. Moreover, Validation metrics (QLOO2
= 0.940, QLMO2
= 0.983 for Q; QLOO2 = 0.837, QLMO2= 0.876 for D) confirming model reliability. These results can complement experimental studies and guide managing risks associated with chemical explosive materials.
