Removal of Phorbol Ester from Jatropha Seedcake Using Ozonation and Solar Irradiation

Jatropha curcas is a well-known source of non-edible vegetable oil that is being promoted as an energy source and high quality feedstock in biodiesel production, especially in developing countries. The potential that the resulting seedcake by-product from jatropha oil extraction (?70% by volume) could also be used as a component in animal feed raises the prospect that a commercially viable jatropha-based industry could be developed. To date, however, the use of jatropha seedcake in livestock feed formulation has been constrained by the presence of phorbol esters (PE), which are known promutagenic and toxic compounds, and by the inability to eliminate PE by cost-effective means. Using seedcake by-product collected from a commercial facility in West Africa that processes jatropha biodiesel, this study demonstrates cost-effective measures of eliminating PE from jatropha seedcake using a combination of solar irradiation and ozonation.     

Structure and Wear Resistance of Coatings on Titanium Alloy and Steels Obtained by Electrospark Alloying with AlN ― ZrB2 Material

We have studied the process of electrospark alloying of titanium alloy VT6 and steels with a composite material based on AlN ZrB₂ with ZrSi₂ additive. We have established that Al₂SiO₅ and ZrSiO₄ forming in the coating directly during its formation play the role of a solid lubricant. Under optimal conditions for electrospark alloying of the titanium alloy, the coefficient of friction is 0.13, the wear is 6 m/km for a sliding velocity of 14 m/sec and a load of 2.56 MPa. Ceramics based on AlN ZrB₂ can be recommended for use as wear-resistant and corrosion-resistant coatings.     

Corrosion of Titanium-Aluminum Intermetallides. Part 2. Electrolytic Oxidation of γ‐TiAl,TiAl3, and α2‐Ti3Al in Sea Water

Potentiodynamic polarization, XRD, Auger electron spectroscopy, and scanning electron microscopy have been applied to determine the mechanisms of electrolytic corrosion of the intermetallides TiAl, TiAl₃, and ₂Ti₃Al in 3% NaCl solution with the addition of MgSO₄ in comparison with the corrosion of the pure metals (Al and Ti). There is comparatively high corrosion resistance in TiAl and Ti₃Al because of the protective action from thin films of rutile TiO₂. Evidence is obtained for the differences between these intermetallides from the appearance of pure titanium on deep anodic polarization (above +0.15 V for TiAl and +0.7 V for Ti₃Al): the aluminum and titanium enter the solution in the forms of Al³⁺ and TiO²⁺ and intermetallides dissolve rapidly. The final solid-state products from anodic oxidation in that case are rutile, magnesium aluminate, and also magnesium and sodium titanates. In addition to pure titanium, TiAl and ₂Ti₃Al as constructional materials may be recommended for use in sea water.     

The formation of Fe–Ga–In nanocomposite particles using mechanochemical interaction of Fe with the Ga–In eutectic

Mechanochemical interaction of Fe powder with the liquid Ga–In eutectic in the Fe-rich concentration corner of the Fe–Ga–In phase diagram was studied and compared with binary Fe–Ga and Fe–In specimens. Slow formation of diluted solid solutions in the Fe–In system was confirmed. In the Fe–Ga system, the dominant concentrated A2 solid solution is formed with H_eff?=?236 kOe, accompanied by ordered D0₃ and L1₂ phases. The Fe–Ga–In system features a stationary equilibrium between the concentrated A2 phase and D0₃ in the iron matrix.     

Nanomaterials for Heterogeneous Combustion

Nanophase materials and nanocomposites, characterized by an ultra fine grain size (less than 100 nm) have attracted wide spread interest in recent years by virtue of their unusual mechanical, electrical, optical, magnetic, and energetic properties. Studies have shown that the thermal behavior of nano‐scaled materials is quite different from micron‐sized powders. Nanosized metallic and explosive powders have been used as solid propellant and explosive mixtures to increase efficiency. At the same time recent studies reveal that the presence of nanosized metals in propellants does not necessary translate into an increased burning rate and burning temperature. The reasons of this effect are far from being clear. This paper presents a new approach to the production of nanocomposites of some energetic materials – ammonium nitrite, cyclotrimethylene trinitramine (RDX), and aluminum – by the vacuum co‐deposition technique. The thermal behavior of the synthesized nanopowder and nanocomposites is investigated. A substantial difference in burning rate of RDX nanopowder has been found in comparison to micron‐sized material. Experimental results allow investigating the effects of nanosized materials on the combustion characteristics.     

Interactions between Polymeric Dispersants and Calcium Silicate Hydrates

To better understand the mechanism of interaction between hydrating silicate-based cements and polymeric dispersants of the type used as superplasticizers in modern construction concretes, two different types of polymeric dispersant were added (at concentrations of 1 and 10 g/L) during the synthesis of calcium silicate hydrate (C-S-H) via the pozzolanic reaction in dilute slurries of lime and reactive silica, at Ca/Si ratios in the range of 0.66–1.50. Although both polymers gave degrees of adsorption of >79% in all cases studied, no significant structural modifications of the resulting C-S-H products were observed via X-ray diffraction or ²⁹Si magic angle spinning–nuclear magnetic resonance. These results differ from recent work in which it was shown that similar types of polymer could intercalate into the interlayers of C-S-H that was made using an alternative process. It is suggested that the process by which the C-S-H is formed may have a strong influence on whether C-S-H can intercalate polymers. This observation is relevant to understanding the fate of such polymers in concrete.     

Oxidation of ZrB2–SiC–ZrSi2 ceramics in oxygen

The oxidation of ZrB₂–SiC and ZrB₂–SiC–ZrSi₂ ceramics of different composition has been studied experimentally at 1500 °C in pure oxygen for up to 50 h. ZrB₂–SiC–ZrSi₂ ceramics proved to be the most oxidation-resistant at ZrSi₂ contents of less then 4 wt%. These ceramics were more oxidation-resistant than ZrB₂–SiC ceramics. An analytical model of growth kinetics for a multilayered scale based on an oxidation–diffusion balance was developed and tested.     

Structure and Properties of TiB2 ― AlN Coatings Made by Spark and Laser Methods

Studies have been done on how various concentrated energy forms (spark discharge and laser beam) affect the formation, composition, and structure of coatings made from the new composite material TiB₂ ― AlN (1:1). The working surfaces have been examined by x-ray phase analysis, microprobe, and metallography. It is found that the composition and structure of a spark coating differ from those of the depositing electrode. The TiB₂ ― AlN material is recommended for hardening low-carbon steels.