An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet.

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.     

Assessing organo-clay dispersion in polymer layered silicate nanocomposites: A SAXS approach

A SAXS method for the quantitative assessment of the morphology of polymer layered silicate nanocomposites is proposed. Fitting the SAXS patterns, the number of clay layers, the periodicity of the layers in the tactoids, the thickness of the regions interposed between the clay platelets and their distributions can be measured. A good agreement with TEM data was obtained, avoiding the inconsistencies with microscopical observations often reported in the literature.     

Comparison of a modified Sugiura procedure with portal systemic shunt for prevention of recurrent variceal bleeding in cirrhosis

BACKGROUND: There is no agreement on the management of patients with cirrhosis and recurrent variceal bleeding after failure of medical or endoscopic treatments or both. Portal systemic shunts are highly effective in preventing rebleeding but are associated with a high incidence of chronic encephalopathy. This study compared the results of a slightly modified Sugiura procedure (esophageal transection plus esophagogastric devascularization plus splenectomy) with those of nonselective portal systemic shunts in patients with previous variceal bleeding. METHODS: Fifty-four patients were included in this randomized controlled study between January 1984 and April 1989. The major end point was chronic encephalopathy. Secondary end points were recurrent variceal bleeding, survival, ascites, and hepatocellular carcinoma. RESULTS: Twenty-seven patients were assigned to each group. The rate of chronic encephalopathy was significantly (p = 0.002) lower after modified Sugiura procedure than after portal systemic shunt. Recurrent variceal bleeding was more frequent after modified Sugiura procedure than after portal systemic shunt, but the difference is not significant. One-, two-, and three-year survival rates were 93%, 81%, and 67%, respectively, in the modified Sugiura group and 78%, 66%, and 39%, respectively, in the portal systemic shunt group (p = 0.044). CONCLUSIONS: These results suggest that the modified Sugiura procedure is better overall than the nonselective portal systemic shunt in the management of patients with cirrhosis and recurrent variceal bleeding. Although the rebleeding rate is higher after the modified Sugiura procedure, this does not seem to affect mortality in these patients.     

Transmission loss allocation through equivalent bilateral exchanges and economical analysis

A new loss allocation (LA) scheme based on the principle of equivalent bilateral exchanges (EBEs) is presented and compared with other available techniques. Formulation and results from extensive simulations including consistency tests show that the suggested methodology has several desirable properties: It is flow-based, requiring only a solved load flow for its implementation; it is not dependent on the choice of a slack bus; it is straightforward to apply; undesirable negative loss allocation is not produced; and low volatilities are shaped. An economic analysis with various LA methods is also carried out when these are integrated into a combined economic dispatch/load flow dispatch strategy, a likely scenario for LA in a real system. This combined dispatch strategy yields prices charged to the loads and rates received by the generators that account for loss allocation and loss supply. Results show that these economic indexes are very close to the marginal costs derived from an optimal power flow (OPF) approach with the advantage of reducing volatility.     

Evaluation of Slow Crack Growth Resistance in Ceramics for High-Temperature Applications

The slow (subcritical) crack growth (SCG) resistance of Si₃N₄ and SiC ceramics has been evaluated by a stepwise loading test on bending bars precracked by Vickers indentation. Three highly refractory materials were selected for the evaluation: i.e., (1) high-purity Si₃N₄ sintered by hot isostatic pressing (HIP) without additives and (2,3) α - and β - SiC pressureless sintered with B and C addition. Under the hypothesis of linear elastic behavior at high temperature, which was found satisfied in the present materials, the SCG resistance was expressed in terms of initial stress intensity factor critical for SCG failure within a predetermined lifetime. The present method was found useful in shortening the testing time and consistent with other traditional fatigue tests (e.g., static-fatigue test): It is recommended as a screening test for materials under research and development. Among the materials tested in the present study, the highest SCG resistance up to 1440°C was found in the high-purity Si₃N₄ without additives.     

Unusual essential oils with aromatic properties

Summary The essential oil obtained by steam distillation of cinchona bark (Cinchona spp.,Rubiaceae family) — a plant well known for its pharmacological properties, also employed in the food industry, especially in making liqueurs - was investigated. The oil, of completely unknown chemical composition, was analyzed by GLC and GLC/MS after separation on a silica gel column, and one hundred components were identified. The presence of 2-hexyl-3-methylmaleic anhydride is rather unusual.

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Ungewöhnliche ätherische Öle mit aromatischen Eigenschaften. Die flüchtigen Aromastoffe der China-Rinde

Zusammenfassung Es wurde ätherisches Öl analysiert, das durch Wasserdampfdestillation von Chinarinde (Cinchona spp. derRubiaceae-Familie) gewonnen wurde. Diese Pflanze ist aufgrund ihrer pharmakologischen Eigenschaften bekannt und wird auch in der Lebensmittelindustrie verwendet, ganz besonders für die Likör- und Magenbitterherstellung. Die chemische Zusammensetzung dieses Öls war unbekannt. Nach Abtrennung auf einer Kieselgelsäule wurden im Öl mit GLC und GLC/MS etwa 100 Verbindungen identifiziert. Das Vorhandensein von 2-Hexyl-3-methyl-maleinsäureanhydrid ist ziemlich ungewöhnlich.

     

Epoxide polymerization

Summary Poly(propylene oxide), PPO, obtained using diphenylzinc, Ph₂Zn, and using the diphenylzinc-water system at various molar ratios H₂O/Ph₂Zn, were studied through ¹H NMR and IR spectroscopy establishing that the polymerization initiates by coordition of propylene oxide (PO) to a terminal zinc atom of the active species followed by consecutive insertions of PO units at this zinc atom. The PPO obtained showed Ph-and HO-, HO-and HO-end-groups depending on the molar ratio H₂O/Ph²Zn used, and also HO-and PhO-end-groups when oxygen was present in the polymerization system.