The corrosion behavior of sputter-deposited aluminum-tungsten alloys

Thin films on aluminum-tungsten alloys were prepared by co-deposition of pure aluminum and pure tungsten, each sputtered by an independently controlled magnetron source, on glass and sapphire substrates. Completely amorphous films were obtained in the Al₈₀W₂₀-Al₆₇W₃₃ composition range. Passivity and corrosion behavior of amorphous Al-W alloys were investigated in 1 M deaerated hydrochloric acid solution using polarization and impedance spectroscopy measurements and have been correlated with the properties of pure alloy components. Tungsten and sputter-deposited Al-W thin films are inherently passive materials while aluminum undergoes pitting corrosion in hydrochloric acid solution. The passive film formed at the OCP on each alloy possesses excellent electric and dielectric properties comparable to those of the isolating film on tungsten. The absolute impedance increases with increasing tungsten content in the alloy. According to electrochemical polarization measurements, alloying Al with W in solid solution significantly enhances the material's resistance to pitting corrosion by shifting the breakdown potential above 2000 mV (Al₆₇W₃₃) and lowering the corrosion rate at the OCP by more than two orders of magnitude. The most likely mechanism explaining the passivity of amorphous Al-W alloys, the Solute Vacancy Interaction Model (SVIM), involves the formation of complexes between highly oxidized solute atoms (W⁺⁶) and mobile cation vacancies, which restrict the transport of Cl⁻ through the oxide film and inhibit its breakdown in hydrochloric acid solution. The role that film stress relaxation effects and microscopic defects in amorphous Al-W films, of the some composition, and deposited on various substrates play in their corrosion resistance is discussed.     

Utilities in the sky?: Comparison of space-based and terrestrial solar power systems

Could huge arrays of space-based solar power systems one day supply utility scale electricity to the electric power grid on earth? How realistic a possibility is this option for alternative energy supply at the moment? Finley R. Shapiro, USA compares space-based and terrestrial solar power systems.     

Analyse de la représentation typique de verbes de procès.

Studied the representational structure of process verbs among preschool children and adults. Three experiments were conducted with a total of 80 French preschool children (5–6 yrs) and 80 French university students. In Exp 1, Ss were presented with 12 verbs and were asked to speak a sentence using the verbs. Use of the verbs as a completed action or as a circumstance was recorded. In Exp 2, the Ss were asked to act out or to mark the action/circumstance of the verb on a drawing representing the verb in a sentence. In Exps 3 and 4, Ss were presented with a list of verbs and asked to indicate whether they represented finished actions or uncompleted actions/circumstances. The number of responses indicating a completed or an uncompleted action/circumstance was compared. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instructional texts rewritten by five expert teams: Revisions and retention improvements.

700 undergraduates were tested in 3 experiments on original or rewritten versions of 52 instructional texts about Army job tasks, general science, philosophy, and history. Five experts had rewritten various sets of the texts and stated hypotheses about the efficacious features of their revisions. We tested their hypotheses and several others. Recall and recognition tests were given immediately and after a 24-hr delay. Results showed that revisions made by 3 of the 5 experts improved retention of text information. The kind and number of revisions and improvements varied across the text sets. Most expert hypotheses were not supported, and they made many revisions they were declaratively unaware of. Some of our hypotheses about the revision features were supported, but different features were effective for different sets of texts. It was concluded that some experts have effective knowledge about improving instructional text, but it exists primarily in procedural form. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antimutagenic activity of phenolic compounds, oligosaccharides and quinolizidinic alkaloids from Lupinus campestris seeds.

There are some foods that contain mutagenic or carcinogenic agents, some of which occur naturally and others that may be formed during preparation or cooking. Several foods such as legumes, also contain natural antimutagens and/or anticarcinogens. Lupine is one such legume that contains high amounts of protein (40%) and oils (14%). About 90 species of lupine have been reported throughout Mexico. However, the use of this crop as a source of food has been limited by the presence of antinutritional agents such as phenolic compounds (PC), carbohydrates (CH) and quinolizidinic alkaloids (Qas). It has also been suggested that consuming these compounds can affect human health and may even reduce the risk of disease. The objective of this work was to determine the effect of PC, CH and Qas, isolated and quantified from Lupinus campestris on the mutagenicity of 1-nitropyrene (1-NP) as a model mutagen and we used the Salmonella typhimurium tester strain YG1024 by the Kado microsuspension method. The results indicate that L. campestris seeds have 11 mg (+)catechin equivalent g(-1) seed coat; 120.3 mg g(-1) seeds and 2.13 mg g(-1) seeds of PC, CH and Qas, respectively. 1-NP mutagenicity was inhibited by 86% for PC, 76% for CH and 75% for Qas at concentrations of 200, 512 and 13.6 microg/tube, respectively.     

A personal computer based system used in electromyography for interpretation and reporting

Programs for rule based electromyography (EMG) interpretation and reporting are described. A number of parameters are obtained during an EMG investigation. The combination of these data leads to a neurophysiological conclusion. Knowledge from the literature, research and experience is the basis for rule development. Rules have been developed for 14 of the most commonly used classifications of an EMG. The syntax is relatively easy and the user may change the rules, add rules or apply the system for other types of data. The results are displayed in a new graphical way. The system presented here is part of an integrated EMG laboratory with administrative routines, distributed databases for storage of results and routines for automatic report generation.     

Simultaneous sulfide and acetate oxidation under denitrifying conditions using an inverse fluidized bed reactor

BACKGROUND: Simultaneous removal of sulfur, nitrogen and carbon compounds from wastewaters is a commercially important biological process. The objective was to evaluate the influence of the CH₃COO^?/NO₃^? molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR). RESULTS: Three molar ratios of CH₃COO^?/NO₃^? (0.85, 0.72 and 0.62) with a constant S^2?/NO₃^? molar ratio of 0.13 were evaluated. At a CH₃COO^?/NO₃^? molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N₂ yield (g N₂ g^?1 NO₃^?‐N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic‐C g^?1 CH₃COO^?‐C consumed. Sulfide was partially oxidized to S⁰, and 71% of the S^2? consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH₃COO^?/NO₃^? molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N₂ and inorganic‐C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S⁰, with a yield of 0.92 g SO₄^2?‐S g^?1 S^2? consumed. CONCLUSIONS: The CH₃COO^?/NO₃^? molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S⁰ or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO₂, S⁰ and N₂ as the major end products. Copyright © 2008 Society of Chemical Industry