Infrared spectroscopic studies of adsorption and catalysis: IV. Aliphatic ketones on silica-supported nickel

The adsorption and decarbonylation of acetone, acetone-d₆, and diethylketone on silica-supported nickel have been studied between 25 and 200 °C using infrared spectroscopy. After a short period of adsorption, two surface species were observed spectroscopically at 25 °. The main one is considered to be the associatively adsorbed ketone R₂CM-OM (M = surface metal atom). The minor one is a carbonyl-containing species possibly involving a complete acetone molecule held to a metal site through a relatively weak σ-bonded interaction with the carbon atom of the carbonyl group, or a π-bonded interaction with the carbonyl group as a whole. Over longer periods of time, bands were observed which are attributable to R₂CH · OSi groups (Si = surface silicon atom of the support). These probably result from the reduction of the ketone to R₂CHOH molecules which then react with OH groups of the silica surface. The hydrogen needed for the reduction process may arise from disproportionation of some of the dissociatively adsorbed species.     

Comparison of various methods for the extraction of total lipids,fatty acids,cholesterol, and other sterols from food products

Seven methods were used to compare the efficiency of total lipid extraction from 13 samples of eight different food products. The methyl esters of fatty acids and the butyrate esters of sterols were prepared and analyzed by gas liquid chromatography. On the basis of total lipid recovered and amounts of fatty acids and sterols present, a chloroform: methanol procedure was selected as the most effective method.     

A methodology for conducting municipal computerization studies

As urban problems become more complex and as accountability and cost minimization become more of a requirement than simply a suggestion computerization is being relied upon to handle the large amounts of data upon which public administrators base decisions. Interdisciplinary teams of faculty and staff from Texas A&M University, in the areas of urban planning, computing science, industrial engineering and accounting, have been involved in studies dealing with several aspects of computerization within municipal organizations. Experience shows that the participation and support of public administrators is vital to the success of the implementation management of computerized systems.This paper develops a staged methodology useful in conducting municipal computerization studies. Investigation of the benefits and disadvantages of computerizing existing manual systems or of a major upgrade of a present computer system is performed via a four staged process. The process highlights the role of the municipal administrator, study team, potential users of the system, and the citizens.When the administrator, the study team members and the future users have a clear understanding of the goals of the system and their goals, the study has a very high chance of being successful. The Texas A&M teams use the methodology discussed here to make a concentrated effort to ensure that all parties have a part in formulating their goals and to understand their role in the design and implementation of the system.     

Burning radionuclide question: what happens to iodine, cesium and chlorine in biomass fires?

Authorization is an important functionality that every hospital information system (HIS) should provide. An authorization mechanism permits information to be accessed only by properly authorized users. Authorization models and mechanisms have been widely investigated within the framework of HISs. However, their implementation into existing systems, that do not any longer meet increased authorization requirements, requires a major redesign effort. This paper describes a front end authorization mechanism that has been developed in an attempt to enhance the security features of an existing HIS without extensive modifications to the system structure.     

The scanning optical microscope (extracts on near-field microscopy)—from a 1975 report

The following consists of extracts concerning near-field microscopy from a Progress Report prepared in April 1975 as Oxford University Engineering Laboratory Report No. 1883/77, describing work initiated by the late Professor R. Kompfner. Preliminary experimental work on near-field microscopy is outlined, and a theory for contrast formation is presented.     

11-beta-hydroxysteroid dehydrogenase activity and gene expression in the hypertensive Bianchi-Milan rat

OBJECTIVE: 11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD), by converting the active steroids cortisol and corticosterone to their inactive metabolites, regulates steroid exposure to the mineralocorticoid and glucocorticoid receptors. We explored the hypothesis that a defect in 11 beta-HSD could result in overstimulation of either the mineralocorticoid or glucocorticoid receptors with subsequent hypertension in an established animal model of hypertension, the Bianchi-Milan hypertensive (BMH) rat. DESIGN AND METHODS: Groups of BMH rats with established hypertension (42-46 days old) and prehypertensive rats (22 days old) were compared with age-matched normotensive control rats. Kidney and liver 11 beta-HSD and glucocorticoid receptor messenger RNA (mRNA) levels were assessed by Northern and dot-blot analyses, and 11 beta-HSD activity as percentage conversion of [3H]-corticosterone to [3H]11-dehydrocorticosterone by tissue homogenate. RESULTS: Hepatic 11 beta-HSD activity and gene expression were significantly reduced in the hypertensive BMH rat compared with its normotensive genetic control. 11 beta-HSD activity was also reduced in the prehypertensive BMH rat (aged 25 days) from hypertensive parents, excluding hypertension per se as the cause of the abnormality. Plasma corticosterone was higher in the hypertensive rats. There was no difference in renal 11 beta-HSD activity or gene expression between hypertensive and normotensive BMH rats, or in glucocorticoid receptor gene expression in the liver or kidney. CONCLUSIONS: Normal levels of renal 11 beta-HSD mRNA and activity are found in the BMH rat. However, the hypertensive BMH rat does demonstrate impaired hepatic 11 beta-HSD activity which occurs at a pretranslational level, although it is not clear how this relates to the pathogenesis of hypertension in this model.     

Improving energy efficiency in manufacturing using peer benchmarking to influence machine design innovation

Clean Technologies and Environmental Policy - Energy efficiency in manufacturing is important for overall sustainability of society. This paper combines three observations to improve an overlooked...     

Three dimensional thermal mechanical coupled simulation during hot rolling of aluminium alloy 3003

Rolling passes of a pass schedule supplied by an aluminium company and containing reliable measured data of roll load and torque is considered. Percentage reductions range from 6% to 20% and are analysed by a commercial thermo-mechanical coupled FEM program FORGE3 V5.3. An inverse analysis method is adopted to match the calculated rolling force and torque with the measured rolling force and torque by treating the friction law and the friction coefficient as free parameters. Three widely accepted friction laws are investigated; Tresca friction, Coulomb friction and viscoplastic friction. The use of viscoplastic friction is shown to yield both more reliable and more accurate results than other models. Significantly the friction coefficient can be traced to remain constant throughout the pass schedule of the breakdown rolling. The contact pressure distribution is then studied with different thickness reductions and compared with published experimental results. The predicted and experimental agreement is such that the load calculation can be regarded as satisfactory. Acceptable agreement is also obtained with the measured torque values. The distribution of equivalent strain, temperature and the stress in the roll gap and the lateral profile are discussed.     

Synthesis and characterisation of a porous Al scaffold sintered from NaAlH<Subscript>4</Subscript>

A simple and cost-effective method for the synthesis of a porous Al scaffold has been optimised using only NaAlH₄ and TiCl₃. The starting materials were compacted into a pellet and sintered under dynamic vacuum to remove the Na and H₂. The sintering conditions, such as vacuum level, temperature, and time, were the key factors that influenced both the extraction of Na and H₂ from the pellet and the overall porosity. Quantitative phase analysis by X-ray diffraction revealed that after the sintering process, the as-prepared porous Al scaffold consisted primarily of Al. Morphological observations conducted by scanning electron microscopy showed that the scaffold exhibited an open network of pores with a small number of mesopores and no formation of micropores. The specific surface area of the scaffold was determined to be 7.9 ± 0.1 and 6.0 ± 0.5 m²/g by the Brunauer–Emmet–Teller method and from small-angle X-ray scattering measurements, respectively. The total porosity of the Al scaffold was 44.6%.