Science and technology of polymeric ablative materials for thermal protection systems and propulsion devices: A review

Ferrocene derivatives constitute an important class of organometallic compounds with not only an extensive range of biological activities but also diverse industrial as well as material science applications. These stimulating features of ferrocene derivatives spurred us to review the recent advances in synthesis methods and biological and other applications reported in the latest literature. An effort has been made to summarize the recent developments in synthetic methods providing access to ferrocene scaffolds and the useful medicinal and material applications, including agricultural, catalytic, polymer, conducting, redox mediating, ferrocenyl stationary phase, rocket propellant and ion sensing applications. Ferrocene-based bulky metallocenes are also discussed.

Recent advances in the synthesis, biological activities and various applications of ferrocene derivatives

The employment of burning rate suppressants in the solid rocket propellant formulation is long known. Different research activities have been conducted to well understand the mechanism of suppression, but literature about the action of oxamide (OXA) and azodicarbonamide (ADA) on the thermal decomposition of composite propellant is still scarce. The focus of this study is on investigating the effect of burning rate suppressants on the thermal behavior and decomposition kinetics of composite solid propellants. Thermogravimetric analysis (TG) and differential thermal analysis have been used to identify the changes in the thermal and kinetic behaviors of coolant-based propellants. Two main decomposition stages were observed. It was found that OXA played an inhibition effect on both stages, whereas the ADA acts as a catalyst in the first stage and as coolant in the second one. The activation energy dependent on the conversion rate was estimated by two model-free integral methods: Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) based on the TG data obtained at different heating rates. The mechanism of action of coolants on the decomposition of solid propellants was confirmed by the kinetic investigation as well.

Thermal behavior and decomposition kinetics of composite solid propellants in the presence of amide burning rate suppressants

Recent research progress in the synthesis and properties of burning rate catalysts based on ferrocene-containing polymers and derivatives

EPDM based heat shielding materials for Solid Rocket Motors: A comparative study of different fibrous reinforcements

The study carried out so far on the application of ethylene-propylene diene rubber (EPDM) in the field of insulation of case bonded solid rocket motors has been reviewed. The various studies by the authors (unpublished work) have also been reported. All these findings bring out the excellent potential of EPDM as insulator in view of its ageing resistance, low-temperature flexibility, low erosion rate, and low specific gravity.

http://publications.drdo.gov.in/ojs/index.php/dsj/article/download/1894/936

Ethylene-propylene Diene Rubber as a Futuristic Elastomer for Insulation of Solid Rocket Motors

Ethylene-propylene diene terpolymer (EPDM)-based insulation system is being globallyused for case-bonded solid rocket motors. A study was undertaken using EPDM as base polymer,blended with hypalon and liquid EPDM and filled with fibrous and non-fibrous fillers. Theseformulations were evaluated as rocket motor insulation system. The basic objective of the studywas to develop an insulation system based on EPDM for case-bonded applications. A series ofrocket motor insulator compositions based on EPDM, filled with particulate and fibrous fillerslike precipitated silica, fumed silica, aramid, and carbon fibres have been studied for mechanical,rheological, thermal, and interface properties. Compositions based on particulate fillers wereoptimised for the filler content. Comparatively, fumed silica was found to be superior as fillerin terms of mechanical and interface properties. Addition of fibrous filler (5 parts) improved thepeel strength, and reduced the thermal conductivity and erosion rate. All the compositions wereevaluated for sulphur and peroxide curing. Superior mechanical properties were achieved forsulphur-cured products, whereas peroxide-cured products exhibited an excellent ageing resistance.Rocket motors were insulated with optimised composition and propellant cast, and the motorswere evaluated by conducting static test in end-burning mode. Defence Science Journal, 2008, 58(1), pp.94-102 , DOI : http://dx.doi.org/10.14429/dsj.58.1628

http://publications.drdo.gov.in/ojs/index.php/dsj/article/download/1628/726

Filled Ethylene-propylene Diene Terpolymer Elastomer as ThermalInsulator for Case-bonded Solid Rocket Motors

Some ferrocene derivatives like 2,4-dinitrophenylhydrazine derivative of acetyl ferrocene, 1-pyrrolidinylmethyl ferrocene, di-ter-butyl ferrocene and 1,3-diferrocenyl-l-butene (DFB) have been synthesised and characterised by infrared, nuclear magnetic resonance, ultraviolet, iron content, etc. To study the effect of their incorporation on performance, ammonium perchlorate/hydroxyl-terminated polybutadiene-based composite propellants containing these derivatives have been prepared and studied for burn rates, tensile strength and percentage elongation followed by their static test evaluation. A comparison of the properties of propellant containing solid and liquid ferrocene derivatives has been made with those containing Fe/sub 2/O/sub 3/ and n-butyl ferrocene, respectively. The data clearly indicates that these ferrocene derivatives are better than Fe/sub 2/O/sub 3/ and n-butyl errocene. Also, DFB is the best among these derivatives. Like composite propellants, DFB increases burn rate in fuel-rich propellants also.

http://publications.drdo.gov.in/ojs/index.php/dsj/article/download/3800/2187

Evaluation of Ferrocene Derivatives as Burn Rate Modifiers in AP/HTPB-Based Composite Propellants

Received: 2013-30-03 Revised: 2013-05-24 Accepted: 2013-05-29 Diarrhea in farm animals, especially in neonatal calves is one of the most challenging clinical syndromes encountered by practicing large animal’s veterinary practitioners throughout the world. Therefore looking into the intricacy of early age calf diarrhea primarily due to E. coli, the present study was designed to perform the isolation and identification of involved E. coli strains in calf diarrhea and also to establish their drug sensitivity pattern. During the study period total 109 faecal samples were collected from diarrheic cattle and buffalo calves less than three months of age from the university teaching veterinary clinics complex, DUVASU, Mathura, University dairy farm, nearby gaushalas located at Vrindavan and Mathura along with the Veterinary Hospitals of western Utter Pradesh located in district Muzaffarnagar, Baghpat, Meerut, Gautambudh Nagar, Ghaziabad and Saharanpur. After laboratory confirmation out of 109 processed samples, only 41 were positive for E. coli. Out of these 41 isolates only 13 revealed the toxin production, hence were pathogenic. On the basis of drug sensitivity test, Amikacin (87.80% sensitivity), Aztreonam (73.17%) and Gentamicin (51.21%) were found to be the effective drugs which could prohibit the growth of E. coli isolates obtained during sudy. However, the presence of 100% resistance against Ampicillin, Cefdinir, Co-trimoxazole, Cloxacillin, Erythyromycin, Lincomycin, Penicillin, Rifampin, Tetracyclin and Vancomycin is matter of concern particularly the resistance against Norfloxacin and Pefloxacin as fluroquinoles are very commonly used in cases of gastroenteritis. All copyrights reserved to Nexus® academic publishers

Incidence and Drug Resistance Pattern of Collibacillosis in Cattle and Buffalo Calves in Western Utter Pradesh in India

A number of composite propellant compositions based on various burn rate suppressants were formulated and studied with the aim to select a suitable burn rate suppressant for reducing the burn rate of the basic propellant composition. Theoretical properties of the compositions were computed by using NASA CEC-71 program and the burn rate performance was evaluated. In addition, sensitivity, thermal, and mechanical properties of the compositions were also evaluated. The composition containing 60% AP, 10% Al, 20% binder, and 10% burn rate suppressant (melamine) was insensitive to friction and impact (28.8 kg and 0.56 m) and showed 90% weight loss. The formulation was found to be relatively superior.

Manoj Gupta

Papers

Ethylene-propylene Diene Rubber as a Futuristic Elastomer for Insulation of Solid Rocket Motors

Filled Ethylene-propylene Diene Terpolymer Elastomer as ThermalInsulator for Case-bonded Solid Rocket Motors

Evaluation of Ferrocene Derivatives as Burn Rate Modifiers in AP/HTPB-Based Composite Propellants

Incidence and Drug Resistance Pattern of Collibacillosis in Cattle and Buffalo Calves in Western Utter Pradesh in India

Study of Burn Rate Suppressants in AP‐Based Composite Propellants