Rapid progress in experimental methodology has made it possible to generate and study highly reactive organometallic fragments in the gas phase. While experimental investigations have focused mainly on the reactivity and thermochemical stability of such species [l-7], parallel developments in ab initio theory have provided descriptions of the molecular and electronic structures of these molecul...

Aluminium-silicon alloys have gained increasing market share in the automotive and aerospace industry because of increased environmental demands. These alloys have a high strength-to-weight ratio, good corrosion resistance, castability and recycling potential. However, variations in properties and limited performance at elevated temperature are restricting these alloys from use at elevated temp...

Nitinol, a group of nearly equiatomic shape memory and superelastic NiTi alloys, is being extensively explored for medical applications. Release of Ni in the human body, a potential problem with Nitinol implant devices, has stimulated a great deal of research on its surface modifications and coatings. In order to use any of the developed surfaces in implant designs, it is important to understan...

welders exposure to nickel and hexavalent chromium in welding fumes is associated with increase of cancer risk in welders. in this study we calculated cancer risk due to exposure to these compounds in welders.the role of exposure parameters in welders on derived incremental lifetime cancer risk were determined by stochastic modeling of cancer risk. input parameters were determined by field inve...

A regression model to predict the thermal expansion coefficient (averaged from room temperature to 538’C) of nonmagnetic nickel-base alloys and austenitic steels was obt,ained. The thermal expansion values used in the regression modelling were ta.kcn from published data bases of commercial alloys. An experimental verification of the model was also conducted on 23 nickel-base laborat,ory heats o...

The determination of four potentially toxic heavy metals, arsenic, chromium, lead and nickel in twelve plant species used for the treatment of perceived HIV and AIDS-associated opportunistic infections by traditional healers in Ngamiland District in Northern Botswana, a metal mining area, was carried out using atomic absorption spectrometry. The medicinal plants; Dichrostachys cinerea, Maerua a...

Water and sediment samples were collected from 20 location of the Buriganga river of Bangladesh during Summer and Winter 2009 to determine the spatial distribution, seasonal and temporal variation of different heavy metal contents. Sequential extraction procedure was employed in sediment samples for the geochemical partitioning of the metals. Total trace metal content in water and sediment samp...

INTRODUCTION Treatment with fixed orthodontic appliances in the corrosive environment of the oral cavity warrants in-vivo investigations of biocompatibility. METHODS Eighteen control and 28 treated subjects were evaluated longitudinally. Four combinations of brackets and archwires were tested. Buccal mucosa cell samples were collected before treatment, and 3 and 6 months after appliance place...

A regional model for atmospheric photochemistry and particulate matter is used to predict the fate and transport of five trace metals: lead, manganese, total chromium, nickel, and cadmium over the continental United States during January and July 2001. Predicted concentrations of the metals are compared to observations. Lead predictions have the lowest mean differences with observations and the...