Tuning the Reactivity of Nanoenergetic Gas Generators Based on Bismuth and Iodine oxidizers

There is a growing interest on novel energetic materials called Nanoenergetic Gas- Generators (NGGs) which are potential alternatives to traditional energetic materials including pyrotechnics, propellants, primers and solid rocket fuels. NGGs are formulations that utilize metal powders as a fuel and oxides or hydroxides as oxidizers that can rapidly release large amount of heat and gaseous products to generate shock waves. The heat and pressure discharge, impact sensitivity, long term stability and other critical properties depend on the particle size and shape, as well as assembling procedure and intermixing degree between the components. The extremely high energy density and the ability to tune the dynamic properties of the energetic system makes NGGs ideal candidates to dilute or replace traditional energetic materials for emerging applications. In terms of energy density, performance and controllability of dynamic properties, the energetic materials based on bismuth and iodine compounds are exceptional among the NGGs. The thermodynamic calculations and experimental study confirm that NGGs based on iodine and bismuth compounds mixed with aluminum nanoparticles are the most powerful formulations to date and can be used potentially in microthrusters technology with high thrust-to-weight ratio with controlled combustion and exhaust velocity for space applications. The resulting nano thermites generated significant value of pressure discharge up to 14.8 kPa m3/g. They can also be integrated with carbon nanotubes to form laminar composite yarns with high power actuation of up to 4700 W/kg, or be used in other emerging applications such as biocidal agents to effectively destroy harmful bacteria in seconds, with 22 mg/m2 minimal content over infected area

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Combustion synthesis in nanostructured reactive systems

New classes of reactive systems which are characterized by nanosized-scale and possessing extremely high reactivity, as compared to similar reactive systems with micro-scale heterogeneity, have attracted attention of researchers. In this review article, the recent developments and trends in combustion science towards the synthesis of nanostructured reactive systems are presented. The emphasis is on combustion of nano-structured reactive systems which includes mechanically induced composite particles, sol-gels, super thermites and multilayer nano-foils. Various applications of combustion synthesized nanostructured reactive systems are also discussed

Thermodynamic analysis of TiO2-Al-C-ZrO2 combustion synthesis system

Combustion Synthesis of Al2O3-TiC-ZrO2 nanocomposites by reaction of TiO2-Al-C-ZrO2 system is a new method with advantages of simplicity and efficiency. Thermodynamic analysis of TiO2-Al-C-ZrO2 system is very important for obtaining ideal phases. In the present work, the possible combustion products are discussed by a new approach of overlapped Phase Stability Diagram (PSD) of Al-O-N, Ti-O-N, Zr-O-N and C-O-N systems. Thermodynamic analysis shows that the desired combustion product is a mixture of Al2O3, TiC and ZrO2. The microstructure and the phase compositions of the combustion products are studied by using X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), respectively.Combustion Synthesis of Al2O3-TiC-ZrO2 nanocomposites by reaction of TiO2-Al-C-ZrO2 system is a new method with advantages of simplicity and efficiency. Thermodynamic analysis of TiO2-Al-C-ZrO2 system is very important for obtaining ideal phases. In the present work, the possible combustion products are discussed by a new approach of overlapped Phase Stability Diagram (PSD) of Al-O-N, Ti-O-N, Zr-O-N and C-O-N systems. Thermodynamic analysis shows that the desired combustion product is a mixture of Al2O3, TiC and ZrO2. The microstructure and the phase compositions of the combustion products are studied by using X-ray Diffraction Analysis (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), respectively