Oxidation Catalysts Based on Antimony Mixed Oxides with Rutile-Type Structures

Several authors have correlated catalyst structure to catalytic behavior in selective oxidation reactions. Sleight [1] reviewed the importance of the scheelite structure for the allylic oxidation and ammonoxidation of olefins; Grasselli and co-workers [2–4] extensively examined the relationship between structure and catalytic activity of bismuth-molybdates, uranium-antirnonates, and bismuth-cerium molybdates. Bordes and Courtine [5] correlated the activity in mild oxidation of 1-butene to the properties of the structure of vanadium-phosphorus oxides. However, little attention has been given in the literature to the role of the rutile structure in allylic oxidation reactions even though the high activity and selectivity of antimony oxides stabilized in matrices with rutile structure (SnO₂ and FeSbO₄) in olefins oxidation and ammonoxidation have been known for several years. Furthermore, Tables 1 and 2 indicate that the kinetic and catalytic behavior of antimony-based catalysts in allylic oxidation reactions are very different from that of molybdate-based catalysts. This suggests that antimony- and molybdate-based catalysts are two distinct classes of catalysts of allylic oxidation, in agreement with a recent suggestion by Grasselli et al. [13].     

Fabrication of microstructures on different materials by diode-pumped solid state laser writing for microfluidics applications

Laser writing attached many attentions for fabrication micro-channels in microfluidics devices and lab-on-chip devices for biomedical applications. In this study, micro-channels were fabricated on different materials as masters using nanosecond diode-pumped solid state (DPSS) laser writing for imprinting on glass and polymer microfluidics devices. Good quality microstructures were fabricated on silicon, nickel alloy, cooper/brass and alumina, respectively by laser writing which proved that the nanosecond DPSS laser is suitable for rapid prototyping and rapid manufacturing of surface microstructures on different substrates as mask-less exposure system of imprinting.     

Resource management model and performance evaluation for satellite communications

Efficient resource management is mandatory to achieve maximum system capacity for next generation communications systems. Resource management deals with the available spectral band, time, power, and space for a transmission signal. It includes (i) the frequency planning, (ii) the selection of transmit power, and (iii) the assignment of the channels and access nodes to the users. The paper presents a generalized notation as well as graph algorithms for resource management problems. Impairment graphs can be used for frequency planning, whereas flow graphs are suitable for channel access problems. To evaluate the performance of the resource management, service criteria (such as blocking or the carrier to interference ratio C/I) or efficiency criteria (bandwidth requirements) can be derived from the graphs. The resource management techniques are applied to satellite networks with non‐geostationary orbits yielding time‐variant network topologies. As a simple example, the channel assignment and capacity optimization of the EuroSky Way system are shown. Furthermore, a comparison of fixed, dynamic and hybrid channel allocation schemes (FCA, DCA, HCA) for a typical MEO satellite scenario is given. Satellite diversity and its impact on bandwidth requirement and transmission quality is also examined. Finally, it is shown how spread spectrum systems can be investigated with the presented tools. Copyright © 2001 John Wiley & Sons, Ltd.     

Bio-ethanol production by fermentation of ricotta cheese whey as an effective alternative non-vegetable source

The aim of the present paper is to investigate the feasibility of bio-ethanol production by batch fermentation of ricotta cheese whey (“Scotta”), a dairy industry waste characterized by lactose concentration ranging from 4.5% to 5.0% (w/w) and, with respect to traditional (raw) whey, by much lower protein content. Scotta, therefore, could represent an effective non-vegetable source for renewable energy production. The microrganism used to carry out the fermentation processes was the yeast Kluyveromyces marxianus. Preliminary experiments, performed in aerobic conditions on different volumes of scotta, have shown the actual growth of the yeast. The subsequent fermentation experiments were carried out, in anaerobic conditions, on three different substrates: scotta, raw cheese whey and deproteinized whey. The experimental data have demonstrated the process feasibility: scotta is an excellent substrate for fermentation and exhibits better performance with respect to both raw cheese whey and deproteinized whey. Complete lactose consumption, indeed, was observed in the shortest time (13 h) and with the highest ethanol yield (97% of the theoretical value).     

Hyperazeotropic ethanol salted-out by extractive distillation. Theoretical evaluation and experimental check

A distillation process for the production of hyperazeotropic ethanol from a dilute wine obtained from the fermentation of biomass has been studied. This process utilizes the coupling of a soft preconcentration stage and of a dehydration stage based on the salting-out effect produced by calcium chloride on the ethanol in an aqueous solution, with the disappearance of the azeotrope. The salt is employed in a close cycle, due to the presence of a regeneration stage, therefore no consumption of calcium chloride is noticed.

The distillation process utilizes one column consisting of two sections operating at different pressures in order to reach an efficient heat recovery.

In this paper, a simplified flow-sheet of the process and the principal operating conditions of the distillation column are illustrated. When compared with other processes, conventional or under development, this one is characterized by the promising reduction of the specific energy requirement.

The operating conditions chosen for the distillation with salt have been experimentally checked using a laboratory column running continuously with calcium chloride as salting-out agent. Moreover, the experiments confirmed the reliability of the mathematical model of the process. Further experiments are in progress with the aim of utilizing a mixture of salts which can be fed from the bottom of the dehydration section back to the fermentor, so that the salt regeneration stage can be reduced.     

Internal and external algorithms for the points-in-regions problem—the inside join of geo-relational algebra

We consider the problem of collectively locating a set of points within a set of disjoint polygonal regions when neither for points nor for regions preprocessing is allowed. This problem arises in geometric database systems. More specifically it is equivalent to computing theinside join of geo-relational algebra, a conceptual model for geo-data management. We describe efficient algorithms for solving this problem based on plane-sweep and divide-and-conquer, requiringO(n(logn) +t) andO(n(log² n) +t) time, respectively, andO(n) space, wheren is the total number of points and edges, and (is the number of reported (point, region) pairs. Since the algorithms are meant to be practically useful we consider as well as the internal versions-running completely in main memory-versions that run internally but use much less than linear space and versions that run externally, that is, require only a constant amount of internal memory regardless of the amount of data to be processed. Comparing plane-sweep and divide-and-conquer, it turns out that divide-and-conquer can be expected to perform much better in the external case even though it has a higher internal asymptotic worst-case complexity. An interesting theoretical by-product is a new general technique for handling arbitrarily large sets of objects clustered on a singlex-coordinate within a planar divide-and-conquer algorithm and a proof that the resulting “unbalanced” dividing does not lead to a more than logarithmic height of the tree of recursive calls.     

Bicyclo‐orthoester as a low‐shrinkage additive in cationic UV curing

A commercially available bicyclo‐orthoester (BOE) was used as low‐shrinkage additive for cationic UV curing of epoxy resins. A high reactivity of BOE by ring‐opening homopolymerization has been observed under cationic UV curing conditions. The BOE and trimethylolpropane triglycidyl ether monomers are compatible and give rise to a cured copolymeric network, under UV irradiation, with a flexibilization increase by increasing the BOE content in the photocurable formulation. Shrinkage after photopolymerization shows a linear reduction by increasing the BOE content in the photocurable formulation; a volume expansion upon polymerization is reached in the presence of 50 wt% of the additive. Copyright © 2007 Society of Chemical Industry     

Production of mycotoxins byFusarium species isolated in Germany

Summary Cultures ofFusarium tricinctum 434 formed large amounts of the trichothecene mycotoxins deoxynivalenol (DON) and 3-acetyldeoxynivalenol (AcDON), as well as the macrocyclic secondary metabolite zearalenone on moistened, autoclaved maize, rice and oats. The formation of zearalenone was low, with levels from 15 to 72 mg/kg as compared to the trichothecene production with maximum quantities of 917 mg/kg of AcDON on rice and 750 mg/kg DON on oats. In the cultures ofF. graminearum 183, total mycotoxin amounts found were lower, with maximum levels of zearalenone up to 150 mg/kg and AcDON up to 160 mg/kg on rice. DON, however, was produced in quantities of about 740 mg/kg on rice.

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Produktion von Mykotoxinen durch in Deutschland isolierte Fusarium-Arten1. Zeitverlauf der Deoxynivalenol-, 3-Acetyldeoxynivalenol-, und Zearalenon-Bildung auf festen Substraten

Zusammenfassung Kulturen vonFusarium tricinctum 434 bildeten auf feuchtem, autoklaviertem Mais, Reis bzw. Hafer relativ hohe Mengen der Trichothecen-Mykotoxine Deoxynivalenol (DON) und 3-Acetyldeoxynivalenol (AcDON) sowie das zu den makrocyclischen Lactonen zählende Mykotoxin Zearalenon. Die Zearalenonbildung war mit Werten von 15 bis 72 mg/kg gegenüber der Trichothecenproduktion mit maximal 917 mg/kg AcDON auf Reis und 750 mg/kg DON auf Hafer deutlich niedriger. In den Kulturen vonF. graminearum 183 wurden insgesamt geringere Toxinmengen gefunden mit maximalen Zearalenon-konzentrationen bis zu 150 mg/kg sowie AcDON Mengen bis zu 160 mg/kg auf Reis. Dagegen erreichte die DON-Bildung auf Reis 740 mg/kg.

     

Einige numerische und experimentelle Untersuchungen zur Plastifizierung eines Fadenverbundwerkstoffes

Durch Modifikation wird die Prandtl-Reuss-Theorie so erweitert, daß im elastisch-plastischen Übergangsbereich die Formänderungskinematik zutreffender beschrieben wird. Mit Hilfe der FEM-Theorie wird nun das elastisch-plastische Modell eines einachsigen Fadenverbundwerkstoffs mit metallischer Matrix beschrieben. Unter transversaler Normalbelastung zeigt dieser Verbund eine rasche Ausdehnung lokaler plastischer Zonen in der Matrix. Die Theorie wird versuchstechnisch verifiziert.     

Isolation of a hydroxytyrosol-rich extract from olive leaves (<Emphasis Type="Italic">Olea Europaea</Emphasis> L.) and evaluation of its antioxidant properties and bioactivity

In this research, a phenol extract of high hydroxytyrosol (OLPE) content was obtained from olive leaves (Olea europaea L.), and subsequently tested under different contexts. The method used to obtain the OLPE basically involved two steps: the use of strongly-acid aqueous steam, generated from 10% HCl (v/v) at 100°C, to directly hydrolyse the native complex phenols from integral olive leaves, and OLPE recovery by liquid–liquid extraction with ethyl acetate. Hydrolysis time was 1 h. Finally, the dried extract was dissolved in distilled water. The OLPE total phenols were determined by Folin–Ciocalteu’s method and by HPLC analysis. Hydroxytyrosol was about 92% of the total phenols present in OLPE, and the yield was about 0.2% on fresh leaves. OLPE showed antioxidant effects on different food lipids and did not inhibit lactic acid bacteria growth; however, it showed cytotoxicity on NIH/3T3 fibroblasts and human umbilical vein endothelial cells at concentrations higher than 0.32 mM (as hydroxytyrosol).