Study of photoactivity of tungsten trioxide (WO3) for water splitting

The paper presents the properties of WO₃ films considering the possibility to build a photoelectrochemical cell (PECC) for hydrogen production. The photocurrent response of the PECC containing WO₃/TCO as photoanode and Pt as cathode was analysed. The morphology, crystalline structure and electrical aspects were investigated. Tungsten trioxide (WO₃) thin film with porous morphology and high crystallinity was obtained using the spray pyrolysis deposition technique.     

Gas-to-Particle Conversion in the Particle Precipitation–Aided Chemical Vapor Deposition Process I. Synthesis of the Binary Compound Titanium Nitride

Particle precipitation-aided chemical vapor deposition (PP-CVD) is a modification of the conventional CVD process, where an aerosol is formed in the gas phase at an elevated temperature, and particles are deposited on a cooled substrate. The synthesis of titanium nitride (TiN), using titanium tetrachloride vapor (TiCl₄), nitrogen (N₂), ammonia (NH₃), and hydrogen (H₂), by the PP-CVD process is studied. TiN is formed by a heterogeneous reaction, using TiCl₄, N₂, H₂, whereas simultaneously TiCl₄ and NH₃ react to form an aerosol. The activation energy of this homogeneous reaction is on the order of 100 kJ/mol. The powder formation process is determined by the dissociation of a titanium containing intermediate species. At low temperature differences between substrate and gas phase (i.e., < 2 K), only dense columnar microstructures, with growth rates of around 20 μm/h, are observed. At these temperature differences no particle deposition is observed. The layers are formed by a molecular diffusion controlled CVD growth mechanism. Porous coherent layers are found in experiments, where intermediate temperature differences are applied (i.e., approximately 2–10 K). The observed interconnection of the particles has to originate from a heterogeneous reaction. Apparently, under these conditions the heterogeneous reaction is fast enough, with respect to the particle precipitation rate, to interconnect the precipitated particles. A further increase in temperature difference between the susceptor and the gas phase only leads to loose powder deposits. In principle, the PPCVD process is a suitable method for the synthesis of thin porous layers of ceramics. To obtain uniform coherent porous layers two separate reaction mechanisms are required under the same experimental conditions. There should be a homogeneous reaction in the gas phase as well as a heterogeneous reaction, which is controlled by surface kinetics, in order to interconnect precipitated particles to obtain a coherent porous layer. Porous ceramic layers can be formed as long as the particle precipitation rate is slow enough with respect to the heterogeneous reaction rate.     

Gas-to-Particle Conversion in the Particle Precipitation–Aided Chemical Vapor Deposition Process II. Synthesis of the Perovskite Oxide Yttrium Chromite

In the particle precipitation-aided chemical vapor deposition process, an aerosol is formed in the gas phase at elevated temperatures. The particles are deposited on a cooled substrate. Coherent layers with a controlled porosity can be obtained by a simultaneous heterogeneous reaction, which interconnects the deposited particles. The synthesis of submicrometer powder of the perovskite oxide yttrium chromite (YCrO₃) by gas to particle conversion, which is the first step of the PP-CVD process, has been investigated, and preliminary results are shown. The powders have been synthesized using yttrium trichloride vapor (YCl₃), chromium trichloride vapor (CrCl₃), and steam and oxygen as reactants. The influence of the input molar ratio of the elements on the composition and characteristics of the powders has been investigated. Phase composition has been determined by X-ray diffraction (XRD). The powders have been characterized by transmission electron microscopy (TEM) and sedimentation field flow fractionation (SF³). At a reaction temperature of 1283 K the powders consist of chromium sesquioxide (Cr₂O₃), or a mixture of Cr₂O₃ and YCrO₃. At stoichiometric input amounts of metal chlorides and steam the formation of YCrO₃ seems to be favored. Two typical particle size distributions have been observed. The primary particle size ranges from 5 to 30 nm for small particles, and from 40 to 250 nm for large particles, depending on the process conditions. The particles tend to be agglomerated. The weight of the agglomerates is independent of the primary particle diameter.     

Integrated synthesis and extraction of short‐chain fatty acid esters by supercritical carbon dioxide

We developed an efficient, integrated reaction‐extraction process for the production of short‐chain fatty acid ethyl esters (FAEE) from milk fat, using carbon dioxide as the only processing solvent. FAEE were synthesized using a short‐chain fatty acid selective lipase. The expansion of the liquid mixture of reactants by dense carbon dioxide enhanced the apparent lipase selectivity. In situ extraction of FAEE by a continuous flow of supercritical carbon dioxide proved to increase the lipase production rate. When the integrated process was operated with alternated periods of synthesis and product removal, the overall selectivity for short‐chain FAEE increased as well, as a result of the combination of the selectivities of lipase and extraction solvent. A two‐fold increase of the lipase productivity was achieved at these conditions, compared to a single batch reaction. The developed process enables the synthesis and isolation of high‐value fatty acid derivatives from a natural source such as milk fat. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Determination of phenol, guaiacol and 4-methylguaiacol in wood smoke and smoked fish-products by gas-liquid chromatography

Summary The determination of phenol, guaiacol and 4-methylguaiacol in smoke and smoked fish products is described. An alkaline fish homogenate is extracted with ethyl ether in order to remove the lipids. After protein precipitation, the phenols are isolated by extraction with chloroform. The chloroform extract is analysed by gas chromatography using a packed column and a flame ionisation detector. Some losses of the phenols during the isolation procedure have been observed. The analytical method developed has been applied to smoke and smoked fish samples from a cold-smoking experiment with a modern smoking kiln.

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Bestimmung von Phenol, Guajacol und 4-Methylguajacol im Holzrauch und in geräucherten Fischerzeugnissen mittels Gas-Flüssigkeit-Chromatographie

Zusammenfassung Die Bestimmung von Phenol, Guajacol und 4-Methylguajacol im Holzrauch und in geräucherten Fischerzeugnissen wird beschrieben. Ein alkalischer, homogenisierter Fischbrei wird mit Äther extrahiert, um die Fette zu entfernen. Nach der Eiweißfällung mit Trichloressigsäure werden die Phenole mittels Chloroform isoliert. Der Chloroform-extrakt wird gaschromatographisch analysiert. Geringe Verluste der Phenolen während der Isolierung wurden festgestellt. Die entwickelte Methode eignet sich zur Analysierung der Räucherrauchs und von Fischproben aus einer modernen Kaltrauchanlage.

     

Nonlinear sorption of three alcohol ethoxylates to marine sediment: a combined Langmuir and linear sorption process?

Alcohol ethoxylates (AE) are nonionic surfactants mainly used in laundry cleaning products. The relation between particle bound and freely dissolved concentrations is an important entity in risk assessment. The mechanistic understanding of AE sorption is still poor, hampering extrapolations from laboratory studies to the field. We studied the sorption of three AE with 8 EO units but with increasing alkyl chains (C10, C12, and C14) to a marine sediment. Solid-phase microextraction, using polyacrylate as the extraction phase, was applied to measure freely dissolved concentrations in pore water. A model that combines a Langmuir and a linear sorption term fitted the nonlinear sorption data to sediment well. At low aqueous concentrations, adsorption dominates over absorption leading to higher distribution coefficients for AE at low field concentrations. This dual-mode model offers the possibility to extrapolate to other AE homologues and other marine sediments and also from high to low field concentrations.     

The Effect of Aliphatic Carboxylic Acids on Olfaction-Based Host-Seeking of the Malaria Mosquito <Emphasis Type="Italic">Anopheles gambiae sensu stricto</Emphasis>

The role of aliphatic carboxylic acids in host-seeking response of the malaria mosquito Anopheles gambiae sensu stricto was examined both in a dual-choice olfactometer and with indoor traps. A basic attractive blend of ammonia + lactic acid served as internal standard odor. Single carboxylic acids were tested in a tripartite blend with ammonia + lactic acid. Four different airflow stream rates (0.5, 5, 50, and 100 ml/min) carrying the compounds were tested for their effect on trap entry response in the olfactometer. In the olfactometer, propanoic acid, butanoic acid, 3-methylbutanoic acid, pentanoic acid, heptanoic acid, octanoic acid, and tetradecanoic acid increased attraction relative to the basic blend. While several carboxylic acids were attractive only at one or two flow rates, tetradecanoic acid was attractive at all flow rates tested. Heptanoic acid was attractive at the lowest flow rate (0.5 ml/min), but repellent at 5 and 50 ml/min. Mixing the air stream laden with these 7 carboxylic acids together with the headspace of the basic blend increased attraction in two quantitative compositions. Subtraction of single acids from the most attractive blend revealed that 3-methylbutanoic acid had a negative effect on trap entry response. In the absence of tetradecanoic acid, the blend was repellent. In assays with MM-X traps, both a blend of 7 carboxylic acids + ammonia + lactic acid (all applied from low density polyethylene-sachets) and a simple blend of ammonia + lactic acid + tetradecanoic acid were attractive. The results show that carboxylic acids play an essential role in the host-seeking behavior of An. gambiae, and that the contribution to blend attractiveness depends on the specific compound studied.     

Floc-based sequential partial nitritation and anammox at full scale with contrasting N2O emissions

New Activated Sludge (NAS^®) is a hybrid, floc-based nitrogen removal process without carbon addition, based on the control of sludge retention times (SRT) and dissolved oxygen (DO) levels. The aim of this study was to examine the performance of a retrofitted four-stage NAS^® plant, including on-line measurements of greenhouse gas emissions (N₂O and CH₄). The plant treated anaerobically digested industrial wastewater, containing 264 mg N L⁻¹, 1154 mg chemical oxygen demand (COD) L⁻¹ and an inorganic carbon alkalinity of 34 meq L⁻¹. The batch-fed partial nitritation step received an overall nitrogen loading rate of 0.18-0.22 kg N m⁻³ d⁻¹, thereby oxidized nitrogen to nitrite (45-47%) and some nitrate (13-15%), but also to N₂O (5.1-6.6%). This was achieved at a SRT of 1.7 d and DO around 1.0 mg O₂ L⁻¹. Subsequently, anammox, denitrification and nitrification compartments were followed by a final settler, at an overall SRT of 46 d. None of the latter three reactors emitted N₂O. In the anammox step, 0.26 kg N m⁻³ d⁻¹ was removed, with an estimated contribution of 71% by the genus Kuenenia, which constituted 3.1% of the biomass. Overall, a nitrogen removal efficiency of 95% was obtained, yielding a dischargeable effluent. Retrofitting floc-based nitrification/denitrification with carbon addition to NAS^® allowed to save 40% of the operational wastewater treatment costs. Yet, a decrease of the N₂O emissions by about 50% is necessary in order to obtain a CO₂ neutral footprint. The impact of emitted CH₄ was 20 times lower.     

Reexamining psychokinesis: Comment on B?sch, Steinkamp, and Boller (2006).

H. B?sch, F. Steinkamp, and E. Boller's (see record 2006-08436-001) review of the evidence for psychokinesis confirms many of the authors' earlier findings. The authors agree with B?sch et al. that existing studies provide statistical evidence for psychokinesis, that the evidence is generally of high methodological quality, and that effect sizes are distributed heterogeneously. B?sch et al. postulated the heterogeneity is attributable to selective reporting and thus that psychokinesis is "not proven." However, B?sch et al. assumed that effect size is entirely independent of sample size. For these experiments, this assumption is incorrect; it also guarantees heterogeneity. The authors maintain that selective reporting is an implausible explanation for the observed data and hence that these studies provide evidence for a genuine psychokinetic effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The referents of trait inferences: The impact of trait concepts versus actor–trait links on subsequent judgments.

The authors investigated the hypothesis that when trait inferences refer to abstract behavior labels they act as a general interpretation frame and lead to assimilation in subsequent judgments of an ambiguous target, whereas when they refer to a specific actor–trait link they will be used as a scale anchor and lead to contrast. Similar to G. B. Moskowitz and R. J. Roman's (see record 1992-31124-001) study, participants who were instructed to memorize trait-implying sentences showed assimilation, and participants who were instructed to form an impression of the actors in these sentences showed contrast. However, exposure to trait-implying sentences that described actors with real names and were accompanied with photos of the actors resulted in contrast under both memorization and impression instructions (Experiment 1). Furthermore, contrast ensued when trait-implying sentences were accompanied with information that suggested a person attribution, whereas assimilation ensued when that information suggested a situation attribution, independent of processing goals (Experiment 2). These findings are interpreted as support for referent-based explanations of the consequences of trait inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)