DIFFERENTIAL EFFECT OF A CHRONIC DOSE OF GAMMA IRRADIATION ON SHRUBS IN THE NORTHERN MOJAVE DESERT.

This report addresses the differential effect of a chronic dose of gamma irradiation on shrubs in the northern Mojave Desert

Energy Absorption Capacity of Prismatic Cellular Metals

There is a growing interest in developing ultra-lightweight armour for agile vehicles. The energy absorption capacity of candidate cellular materials with a range of prismatic structures has been studied while undergoing different impact velocities. The prismatic structures studied are appropriate to bullet resistant materials. Energy absorption per unit mass, and the distribution of plastic strain, has been used to assess the structures. This work was in collaboration with BAE SYSTEMS and led to a DTI: Competition of Ideas grant award (£300k).In this study the energy absorption capacity of prismatic cellular materials were examined using 2D Finite-Element (FE) simulations. The energy absorption capacity of many core topologies has been predicted under quasi-static compression. Subsequently, the dynamic impact behaviour of one of these structures, with good energy absorption characteristics, has been assessed for a range of impact velocities from 10 to 1000 m/s. As the impact speed increases, different deformation modes are noticed and the effects of stress wave propagation become more important. The importance of these studies is identified for the future development of lightweight, and impact-resistant, structured materials

THE ROLE OF SHRUBS ON REDISTRIBUTION OF MINERAL NUTRIENTS IN SOIL IN THE MOJAVE DESERT

Volume: 4Start Page: 124End Page: 13

Phosphines with N-Heterocyclic Boryl-Substituents : Ligands for Coordination Chemistry and Catalysis

Boryl-substituted phosphines NHB-P(R)Ph (R = H, Ph, NHB = N-heterocyclic boryl substituent) react with Fe-2(CO)(9) to give isolable Fe(CO)(4) complexes, two of which were characterized by single-crystal XRD studies. The electronic and steric properties for a series of the boryl phosphines were further assessed by evaluation of TEPs for in-situ formed complexes [RhCl(NHB-(PRR2)-R-1)(CO)(2)] (R-1, R-2 = H, Ph, Me, NMe2), and calculations of buried volumes for Fe(CO)(4) complexes. The results imply that the NHB-phosphines exhibit due to their conformational flexibility some variability in their steric bulk, and that some specimens may exhibit similar electron releasing power and steric demand as tBu(3)P. Studies of the amination of bromobenzene with 2,6-diisopropylaniline confirmed that these properties can be exploited to promote Pd-catalyzed C-N cross coupling reactions, and that formal replacement of a phenyl by a NHB substituent in the auxiliary phosphine has a beneficial effect on catalyst performance.Peer reviewe