Raman spectra of supported molybdena catalysts: II. Sulfided,used, and regenerated catalysts

Raman spectroscopy has been used to investigate the structural changes that two supported molybdenum oxide catalysts undergo upon specific chemical treatments. Molecular MoS₂ structures are indicated after sulfidation by a mixture of $\text{H}{}_2\text{H}{}_2\text{S}$. Catalyst samples used in a coal hydrodesulfurization process yield spectra dominated by intense scattering from carbon deposited in the pores of the catalyst. Spectra of used catalyst samples, subjected to controlled air-firing to 600 °C, show that all of the spectral features of the unused catalyst are not recovered after this “regeneration” procedure.     

Preparation and anisotropic mechanical behavior of highly‐oriented electrospun poly(butylene terephthalate) fibers

This work describes the effect of the speed of drum‐type rotating collector in an electrospinning process on the orientation of electrospun poly(butylene terephthalate) fiber mats, and its effect on the tensile properties. The degree of orientation increased with the increase in the drum speed (surface velocity) up to a critical level, and thereafter, wavy fibers were observed. The average diameter reduced and its distribution became narrower with increase in the velocity. The mechanical properties in a parallel direction improved about three times with increase in the surface velocity. The anisotropic mechanical behavior could be predicted with a simple classical equation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2017–2021, 2006     

Evidence aggregation networks for fuzzy logic inference

Fuzzy logic has been applied in many engineering disciplines. The problem of fuzzy logic inference is investigated as a question of aggregation of evidence. A fixed network architecture employing general fuzzy unions and intersections is proposed as a mechanism to implement fuzzy logic inference. It is shown that these networks possess desirable theoretical properties. Networks based on parameterized families of operators (such as Yager's union and intersection) have extra predictable properties and admit a training algorithm which produces sharper inference results than were earlier obtained. Simulation studies corroborate the theoretical properties.     

Sago starch saccharification and simultaneous ethanol fermentation by amyloglucosidase and Zymomonas mobilis

Simultaneous saccharification and ethanol fermentation (SSF) of sago starch was studied using amyloglucosidase (AMG) and Zymomonas mobilis. The optimal concentration of AMG and operating temperature for the SSF process were found to be 0.5% (v/w) and 35°C, respectively. Under these conditions with 150 g dm^?3 sago starch as a substrate, the final ethanol concentration obtained was 69.2 g dm^?3 and ethanol yield, Y_P/S, 0.50 g g^?1 (97% of theoretical yield). Sago starch in the concentration range of 100–200 g dm^?3 was efficiently converted into ethanol. When compared to a two-step process involving separate saccharification and fermentation stages, the SSF reduced the total process time by half.     

Suicide by fire: a contemporary method of political protest

Suicide by fire (self-incineration)for the purpose of political protest has appeared in several countries during the previous decade. In this paper, the history of this form of suicide has been explored. The authors examined all cases of suicide by fire reported in the London Times and New York Times between 1790 and 1972. Seventy-one per cent of these reported suicides occurred during the most recent decade, 1963 to 1972, with all cases of political self-incineration occurring during this period. The socio-cultural context in which this form of protest may occur, and the psychological factors in individuals who choose this method of suicide are both discussed. It is suggested that the occurrence of self-incineration as a means of political protest may be yielding to more aggressive acts of terrorism as popular methods of forcing political change.     

Single Particle and Collective Effects Observed in the Electron Beam of the Maryland ERA Experiment

The formation of rotating, relativistic electron beams with properties suitable for collective ion acceleration has been studied under a variety of experimental conditions. A straight, cylindrical, relativistic electron beam (typical energy 2-3 MeV, typical current 2-10 kA) is passed through a narrow magnetic cusp, and the resulting rotating downstream beam has been studied using a number of diagnostic techniques. Two current regimes have been investigated: one in which the self-fields of the downstream electron beam are small compared to the applied fields, and one in which the self-fields are comparable to the applied fields. The beam characteristics in both regimes have been compared to single particle expectations. Experiments have also been conducted in which the effect of an inner and outer conducting boundary on the time-resolved beam cross section has been measured. Results will be discussed in the context of collective ion acceleration experiments now in preparation.     

Solubility of nitrogen in CaO-SiO2-CaF2 slag system

Equilibrium experiments between gas and slag were carried out to understand the thermodynamic behaviour of nitrogen in the CaO-SiO₂-CaF₂ slag system at 1600°C. The solubility of nitrogen in this slag system increased as the oxygen potential decreased and as the reaction temperature increased. The values of the nitride capacity have a minimum at about 2.0 slag basicity, having higher values in both more acidic and basic regions. This may be explained by two mechanisms for nitrogen dissolution; incorporated nitride ion and free nitride ion state. In slag with 2.0 basicity or less, MgO content increased the nitride capacity slightly. At higher slag basicity, however, nitride capacity decreased with MgO content. The effects of BaO to substitute CaO on nitride capacity showed similar behaviour as MgO. This complex relationship between basicity of slag and nitride capacity is explained by using optical basicity. It was found that nitride capacity and optical basicity had a close relationship even in the different basic oxide systems.     

Modelling the P2Y purinoceptor using rhodopsin as template

The P2Y1 purinoceptor cloned from chick brain (Webb, T. et al (1993) FEBS Lett., 324, 219-225) is a 362 amino acid, 41 kDa protein. To locate residues tentatively involved in ligand recognition a molecular model of the P2Y purinoceptor has been constructed. The model was based on the primary sequence and structural homology with the G-protein coupled photoreceptor rhodopsin, in analogy to the method proposed by Ballesteros and Weinstein ((1995) Meth. Neurosci. 25, 366-428). Transmembrane helices were constructed from the amino acid sequence, minimized individually, and positioned in a helical bundle. The helical bundle was then minimized using the Amber forcefield in Discover (BIOSYM Technologies) to obtain the final model. Several residues that have been shown to be critical in ligand binding in other GPCRs are conserved in the P2Y1 purinoceptor. According to our model the side chains of these conserved residues are facing the internal cleft in which ligand binding likely occurs. The model also suggests four basic residues (H121 in TM3, H266 and K269 in TM6 and R299 in TM7) near the extracellular surface that might be involved in ligand binding. These basic residues might be essential in coordinating the triphosphate chain of the endogenous ligand adenosine 5'-triphosphate (ATP). Potential binding sites for agonists have been explored by docking several derivatives (including newly synthesized N6-derivatives) into the model. The N6-phenylethyl substituent is tolerated pharmacologically, and in our model this substituent occupies a region predominantly defined by aromatic residues such as F51 (TM1), Y100 (TM2) and F120 (TM3). The dimethylated analogue of ATP, N6,N6-dimethyl-adenosine 5'-triphosphate, is less well tolerated pharmacologically, and our model predicts that the attenuated activity is due to interference with hydrogen bonding capacity to Q296 (TM7).     

Adhesive capsulitis of the shoulder joint: usefulness of dynamic sonography

We studied the value of dynamic sonography in adhesive capsulitis of the shoulder joint in patients with clinically suspected frozen shoulder. The sonographic criterion of adhesive capsulitis was continuous limitation of the sliding movement of the supraspinatus tendon against the acromion of the scapula. Arthrography was regarded as a gold standard in the diagnosis of adhesive capsulitis against which the sonographic results were compared. Among 23 patients with arthrographically documented adhesive capsulitis, sonographic examination showed limitation of movement of the supraspinatus tendon in 21. This sonographic sign therefore has a sensitivity of 91%, a specificity of 100%, and an accuracy of 92% for detecting adhesive capsulitis, making dynamic sonography a reliable technique for the diagnosis of this condition.