Abstract  The present work demonstrates the application of a hydrodynamic cavitation reactor for the synthesis of biodiesel with used frying oil as a feedstock. The synthesis involved the transesterification of used frying oil (UFO) with methanol in the presence of potassium hydroxide as a catalyst. The effect of geometry and upstream pressure of a cavitating orifice plate on the rate of transesterification reaction has been studied. It is observed that the micro level turbulence created by hydrodynamic cavitation somewhat overcomes the mass transfer limitations for triphasic transesterification reaction. The significant effects of upstream pressure on the rate of formation of methyl esters have been seen. It has been observed that flow geometry of orifice plate plays a crucial role in process intensification. With an optimized plate geometry of 2 mm hole diameter and 25 holes, more than 95% of triglycerides have been converted to methyl esters in 10 min of reaction time with cavitational yield of 1.28 x 10(-3) (Grams of methyl esters produced per Joule of energy supplied). The potential of UFO to produce good quality methyl esters has been demonstrated. (c) 2012 Elsevier B.V. All rights reserved.

Abstract  This work describes the electrochemical behavior of Ni(II) pyromellitic acid (PMA) film immobilized on the surface of bimetallic Au-Pt inorganic-organic hybrid nanocomposite carbon nanotube glassy carbon electrode and its electrocatalytic activity toward oxidation of glucose. The surface structure and composition of the sensor was characterized by scanning electron microscopy (SEM). Electrocatalytic oxidation of glucose on the surface of modified electrode was investigated with cyclic voltammetry and rotating disk electrode (RDE) voltammetry methods. The results showed that nickel pyromellitic acid films on bimetallic Au-Pt inorganic-organic hybrid nanocomposite carbon nanotube glassy carbon electrode have excellent electrochemical catalytic activity toward glucose oxidation. The hydrodynamic amperometry at rotating modified electrode at constant potential versus reference electrode was used for detection of glucose. Under optimized conditions, the calibration plots are linear in the concentration range of 100 nM to 100 mu M and detection limit was found to be 55 nM. The modified electrode showed reproducible behavior and a high level of stability during electrochemical experiments, making it particularly suitable for analytical purposes. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  The plant products are the most promising source for their biological activity against various pests. The strong inhibition of Acetylcholinesterase (AchE: EC 3.1.1.7) is the principal underlying mechanism of action of most of the potential pesticides. In the present study, the newly moulted penultimate instar nymphs of the desert locust Schistocerca gregaria were treated with methanolic (at concentration levels: 7.5 or 3.7%), petroleum ether or n-butanolic (at 30 or 15%) extract from the wild herb Fagonia bruguieri. The AchE activity was determined in the haemolymph and fat body of the last instar nymphs and newly formed adult females. Along the nymphal life, remarkably induced AchE activity was unexceptionally observed in the haemolymph, especially of the early- and mid-aged nymphs. With regard to the enzyme activity in the fat body of S. gregaria nymphs, pronouncedly inhibited activity in the early-aged nymphs, regardless of the extract or its concentration level. The strongest prohibiting effect was exhibited by both the petroleum ether and n-butanolic extracts. On the contrast, AchE activity was enhanced in the fat body of all nymphs other than the early-aged ones. The F bruguieri extracts exerted a potent inhibitory action on the AchE activity in the haemolymph of the newly emerged adults of S. gregaria. Such action was reversed on the AchE activity in the fat body of adults, whatever the extract or concentration level. The present results suggest that the wild herb F. bruguieri may prove to be a probable candidate for the development of biopesticides to control the populations of the desert locust as safer, ecofriendly and economic alternatives to the synthetic pesticides.

Abstract  The dynamics of photoisomerization of 3,3' diethyloxadicarbocyanine iodide (DODCI) has been investigated inside micellar environment formed by a surfactant-like ionic liquid, 1-butyl-3-methylimidazolium octyl sulfate ([C(4)mim][C8SO4]) and also in binary mixture of another ionic liquid, N,N,N-trimethyl-N-propyl ammonium bis- (trifluoromethanesulfonyl) imide, (N-3111][Tf2N]) with methanol, acetonitrile, and n-propanol by using steady-state and picosecond time-resolved fluorescence spectroscopy. The entrapment of DODCI into the [C(4)mim][C8SO4] micellar environment led to the enhanced fluorescence intensity along with similar to 13 nm red shift in the emission maxima. A sharp increase in the fluorescence quantum yield (Phi) and the lifetime (tau(f)) near the critical micelle concentration (cmc) range is observed followed by saturation at higher concentration. As a result of partitioning of the probe molecules in the micellar phase from water, the nonradiative rate constant (k(nr)) of DODCI decreases 2.7 times than in water. The retardation of isomerization rate is due to high microviscosity of the micellar system compared to bulk water. In order to understand how the rate of isomerization depends on polarity as well as viscosity, we have measured isomerization rate in neat [N-3111][Tf2N] and its mixtures with polar solvents, like methanol, acetonitrile, and n-propanol. The addition of methanol and n-propanol increases the polarity, but viscosity of the medium decreases. The nonradiative rate constant that represents the rate of photoisomerization decreases with the addition of the polar solvent in [N-3111] [Tf2N]. Complete analysis of all the experimental results indicate that viscosity is the sole parameter that regulates the rate of photoisomerization. Temperature-dependent k(nr) are used to determine the activation energy (E-a) in 100 mM [C(4)mim][C8SO4] solution and neat [N-3111][Tf2N] system.

Abstract  The optimal utilisation of fuels such as hydrogen and methanol in micro fuel cells (MFC) in combination with effective fuel storage solutions can offer much longer operational and standby time and shorter recharging time compared to batteries. Therefore, MFCs have an immense potential to replace or to be used in combination with batteries for portable power applications. However, the overall fuel cell system is required to be compact to suit the appliance, have a simple support system, manufacturable at a mass scale with low cost materials and fabrication technologies, and have lifetimes significantly longer than batteries. In a fuel cell stack, the interconnect plates occupy majority of the volume of the stack, and reducing their size (thickness) and weight would be enormously beneficial in terms of improving the power density of the device. Therefore, the purpose of this study is to investigate design options of the interconnect plate for operation of the stack under ambient and passive conditions. Three stacks (power output in the 3-12 W-e range) were built using two designs and lifetime tests were performed up to 21,000 h using industrial grade hydrogen under both constant and simulated cyclic loads. The voltage-current characteristics of the stacks were analysed by model equations and the overall performance was assessed by performing energy balance calculations. The major source of cell degradation, increasing amplitude of voltage fluctuations and manifestation of limiting current behaviour for some cells have been discussed and appear to be related to the poisoning of Pt catalyst by impurities such as S, Hg and CO present in the industrial grade hydrogen used in the study, leading to increasing loss of electrochemical active surface area of the catalyst with time. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Abstract  This study demonstrates the use of MALDI-TOF/TOF CID fragmentation for the identification of expected and ""unexpected'' side products in a complex mixture of melt polymerized poly(butylene adipate) (PBA), which aged at room temperature, unexposed to direct sunlight and extreme temperature fluxuations. Expected products include PBA structures terminated with butanediol, adipic acid and buteneol (due to dehydration during synthesis); as well as cyclic architectures with no terminal groups. Additionally, side products were observed containing ""unexpected'' terminal groups such as glycol, propenyl, methanol, and aldehydes. Low energy fragmentation pathways and computational data are presented to verify the structural assignments of the identified structures, followed by discussion of their probable origin. 1,5-Hydrogen shift reactions were identified as the major low-energy fragmentation pathway.

Abstract  BACKGROUND: Chitosan (AC) and five hydroalcoholic extracts from Lithospermum erythrorhizon (SE), Rheum palmatum (RE), Thymus vulgaris (AT), Lippia citriodora (PLX) and a mixture of Rosmarinus officinalis, Salvia lavandulifolia and Thymus mastichina (LA) were tested for antimicrobial activity against bacteria, yeasts and filamentous fungi using two broth dilution methods. The effects of adding single extracts on naturally occurring micro-organisms and sensory qualities of raw tomato juice were also evaluated. RESULTS: SE extract exhibited the strongest activity, with minimum inhibitory concentrations (MICs) of 100-400 mu g mL-1 for Gram-positive and 1600-3200 mu g mL-1 for Gram-negative bacteria. Enterobacter aerogenes showed the greatest susceptibility to AC (MIC 1600 mu g mL-1). Lethal effects of extracts and AC were achieved at a minimum bactericidal concentration (MBC)/MIC ratio of 2 in 88% of assays. SE and RE extracts and AC also exhibited antifungal effect against yeasts, but they had no activity on filamentous fungi. Control and 100 mg L-1 SE-added tomato juices did not differ in acceptance, but this SE concentration was not effective in the control of microbial load throughout cold storage. CONCLUSION: Results confirm the antimicrobial potential of the plant extracts, but additional research is needed until the agents responsible for the activities have been determined in order to use them as natural constituents of multiple-barrier food preservation systems. Copyright (C) 2012 Society of Chemical Industry

Abstract  We report an effective and simplified procedure for the synthesis of cross-linked alkaline anion-exchange membranes (AEMs). A new monomer containing two tertiary amine groups on 4,4a2-dihydroxydiphenyl ether (DABPE) is used in nucleophilic aromatic substitution step-growth copolymerization with 4,4a2-difluorobenzophenone, 2,2a2,6,6a2-tetramethyl-4,4a2-biphenol to obtain the corresponding poly(arylene ether ketone) copolymers containing tertiary amine groups. After partial quaternization, the residual tertiary amine groups of the polymer react with p-xylylene dichloride to produce a cross-linked membrane, which is followed by anion exchange with hydroxide ions. The resulting cross-linked membranes exhibit high hydroxide ion conductivity (above 10a2 S cma1 at room temperature), good mechanical properties, and reduced water uptake relative to the linear uncross-linked membrane. This facile synthetic approach enables the preparation of cross-linked materials with the potential to meet the demands of hydrogen-powered fuel cells as well as direct methanol fuel cells.

Abstract  We have shown that low viscosity alkyl or hydroxyalkyl ammonium formate (ILs) can dissolve agarose, and higher dissolution can be achieved in the mixed, alkyl or hydroxyalkyl ammonium + imidazolium or pyridinium ILs. The polarity parameters alpha , beta , pi *, E sub(T)(30) and E sub(T) super(N) of these IL systems were measured to explain their dissolution ability for agarose. Dissolved agarose was either regenerated using methanol as a precipitating solvent or ionogels were formed by cooling the agarose-IL solutions to ambient temperature. Exceptionally high strength ionogels were obtained from the agarose solutions in N-(2-hydroxyethyl)ammonium formate or its mixture with 1-butyl-3-methylimidazolium chloride. Regenerated material and ionogels are characterized for their possible degradation/conformational changes and gel properties (thermal hysteresis, strength, viscoelasticity and conductivity) respectively. A high strength, high conducting ionogel was demonstrated to be able to build an electrochromic window. Such ionogels can also be utilized for other soft matter electronic devices and biomedical applications.

Abstract  Thermodynamic restrictions and simultaneous effects of operational conditions on the homogeneous rhodium-catalyzed carbonylation of methanol are studied in this line of research. It is shown that the general NRTL-Virial model can be appropriated to study thermodynamics of the carbonylation. It is obtained that the reaction is kinetically and thermodynamically reasonable at temperatures above 420K and below 520K, respectively. Moreover, at carbon monoxide partial pressures above 10 bar, the reaction rate is independent of the partial pressure. These results are in full accord with those reported in the literature. In addition, P-CO > 2 bar is necessary for initializing the reaction. The parameters involved in the rate expression, equilibrium constants, CO solubility, and rate constant, are determined. The equilibrium constants are calculated with B3LYP/SDD ab initio method, and the value of Henry's coefficient for CO (H-CO) is determined as a function of temperature and methyl acetate conversion. The results predicted by this function agree well with those proposed by the general NRTL-Virial model with the errors below 11%. The Variation of CO solubility with acetic acid and methyl acetate concentrations is in good agreement with that obtained by others. It is found that the determined parameters give satisfactory predictions in modeling and simulation of the reaction.

Abstract  Seven aliphatic dicarboxylic acids (C3-C9) along with phthalic acid, pinic acid and pinonic acid were determined in 35 aerosol (PM10) samples collected over the year at Vavihill sampling station in south of Sweden. Mixture of dichloromethane and methanol (ratio 1:3) was preferred over water for extraction of samples and extraction was assisted by ultrasonic agitation. Analytes were derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) containing 1% trimethylsilyl chloride and analyzed using gas chromatography/mass spectrometry. Among studied analytes, azelaic acid was found maximum with an average concentration of 6.0 plus or minus 3.6 ng m super(-3) and minimum concentration was found for pimelic acid (1.06 plus or minus 0.63 ng m super(-3)). A correlation coefficients analysis was used for defining the possible sources of analytes. Higher dicarboxylic acids (C7-C9) showed a strong correlation with each other (correlation coefficients (r) range, 0.96-0.97). Pinic and pinonic acids showed an increase in concentration during summer. Lower carbon number dicarboxylic acids (C3-C6) and phthalic acid were found strongly correlated, but showed a poor correlation with higher carbon number dicarboxylic acids (C7-C9), suggesting a different source for them. Biomass burning, vehicle exhaust, photo-oxidation of volatile organic compounds (natural and anthropogenic emissions) were possible sources for dicarboxylic acids.

Abstract  Coal based polygeneration, a technology that couples power generation and chemical production, is a promising solution to the challenges of fossil fuel depletion and greenhouse gas emissions. Carbon monoxide shift process is a key unit in polygeneration, which adjusts hydrogen and CO ratio according to the requirements of downstream processes. Usually steam is added to shift the gas composition extensively, which contributes considerably to the energy efficiency penalty. This paper presents a polygeneration system with a low steam demand CO shift process, based on a recently developed catalyst QDB-04. Compared with a conventional CO shift, the proposed process is characterized by a low steam to CO ratio in the feeding syngas, and the steam required for the CO shift can be significantly reduced. A model of the proposed CO shift process was developed and its performance was compared with a conventional CO shift. Key system parameters were chosen to integrate the low steam CO shift process in a methanol/power polygeneration system. Based on flowsheet simulation, an energy assessment was performed to compare the proposed polygeneration system with a conventional one. Results show that the polygeneration with the low steam CO shift process has considerable energy savings over the conventional scheme.

Abstract  This paper describes biodiesel production using heterogeneous alkaline catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction, in the search for more profitable and sustainable alternatives regarding biodiesel production. The heterogeneous catalytic process has many differences from that currently used in industrial homogeneous processes. The main advantage is that it requires lower investment costs, as there is no need for separation steps such as methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This paper also describes experimental work towards the development of new heterogeneous alkaline catalysts able to produce biodiesel from vegetable oils. The research has resulted in the selection of CaO and CaO modified with alkaline and alkaline earth metal catalysts. They show very good catalytic performances with high activity and stability. In fact, biodiesel (FAME) yields higher than 94% were observed in several consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production.

Abstract  The latest developments of the jet compression refrigeration and hybrid jet compression refrigeration systems are presented. From theoretical and experimental studies, their operating conditions and the coefficients of performance are given. Also, the importance of the working fluid in the performance of the system is emphasized in conjunction with the intercooler, which allows the use of two different refrigerants at a time in the jet and compressor subsystems. Searching appropriate refrigerants, some theoretical and experimental studies show the advantages of using R134a in these systems. However, the use of hydrocarbon refrigerants is proposed as a good option, although research and some safety procedures have to be developed before applying these ""nature friendly"" refrigerants. (C) 2011 Elsevier Ltd and IIR.

Abstract  (S)-Warfarin 7-hydroxylation and midazolam 1'-hydroxylation are among the preferred probe substrate reactions for CYP2C9 and CYP3A4/5, respectively. The impact of solvents on enzyme activity, kinetic parameters, and predicted in vivo hepatic clearance (Cl(H)) associated with each reaction has not been evaluated. The effects of increasing concentrations [0.1-2% (v/v)] of six organic solvents (acetonitrile, methanol, ethanol, dimethyl sulfoxide, acetone, isopropanol) were first tested on each reaction using human liver microsomes (HLMs), human intestinal microsomes (midazolam 1'-hydroxylation only), and recombinant enzymes. Across enzyme sources, relative to water, acetonitrile and methanol had the least inhibitory effect on (S)-warfarin 7-hydroxylation (0-58 and 9-96%, respectively); acetonitrile, methanol, and ethanol had the least inhibitory effect on midazolam 1'-hydroxylation (0-29, 0-22, and 0-20%, respectively). Using HLMs, both acetonitrile and methanol (0.1-2%) decreased the V(max) (32-60 and 24-65%, respectively) whereas methanol (2%) increased the K(m) (100%) of (S)-warfarin-hydroxylation. (S)-Warfarin Cl(H) was underpredicted by 21-65% (acetonitrile) and 13-84% (methanol). Acetonitrile, methanol, and ethanol had minimal to modest impact on both the kinetics of midazolam 1'-hydroxylation (10-24%) and predicted midazolam Cl(H) (2-20%). In conclusion, either acetonitrile or methanol at ≤0.1% is recommended as the primary organic solvent for the (S)-warfarin 7-hydroxylation reaction; acetonitrile is preferred if higher solvent concentrations are required. Acetonitrile, methanol, and ethanol at ≤2% are recommended as primary organic solvents for the midazolam 1'-hydroxylation reaction. This information should facilitate optimization of experimental conditions and improve the interpretation and accuracy of in vitro-in vivo predictions involving these two preferred cytochrome P450 probe substrate reactions.

Abstract  In this paper, a method for the detection of norbixin and tartrazine in sugar by means of resonance Raman spectroscopy is presented. The extraction was done in four steps using methanol and the measurements were performed in aqueous solution. The excitation wavelength was 514 nm for norbixin and 488 nm for tartrazine samples. The characteristic resonance Raman signals of the dyes were fitted by different functions. Depending on the R² values of the different fits, each spectrum was classified as positive or negative response. A detection limit of 250 ng g⁻¹ for norbixin and 989 ng g⁻¹ for tartrazine in solid sugar samples could be reached by logistic regression.

Abstract  The present investigation was focused on improving the feasibility of large scale applications of a solid phase extraction (SPE) procedure dedicated to the recovery of polyphenols from olive mill wastewaters (OMWs). To this aim, a previously developed SPE procedure was optimized in terms of contact time without negatively affecting the overall process productivity. The possibility of regenerating and recycling both the solid phase (Amberlite XAD16 non-polar resin) and the extraction solvent (acidified ethanol) was also demonstrated. In particular, the resin was successfully reused in 10 consecutive SPE cycles (including washing and reactivation steps), allowing almost constant polyphenols adsorption and desorption ratios (81.44 +/- 0.91% and 52.69 +/- 5.57%, respectively). Up to 695 mL of ethanol per liter of exhausted extraction solvent were recovered by means of a rotary evaporator. Furthermore, the solvent conventionally used for resin activation (i.e., methanol) was successfully substituted by a more biocompatible solvent (i.e., ethanol). An ORAC value corresponding to 6979 mu M of Trolox equivalents was observed for the concentrated polyphenolic solution, obtained as a result of rotary evaporator operations. Importantly, no substantial loss of radical scavenging and antioxidant activities occurred by means of the aforementioned operations dedicated to the recovery of ethanol from the obtained polyphenolic solution.

Abstract  The synthesis of the bis-cyclometalated complexes [M(ptpy) (2)(S2COCH3)] (M = Rh, 1; M = Ir, 2; ptpy = 2-(p-tolyl)pyridinato) from [{M(mu-Cl)(ptpy)(2)}(2)], carbon disulfide and sodium methanolate as the base are described. Compound 1 and 2, respectively, were crystallized from dichloromethane/methanol and the molecular structures of both complexes were confirmed by single-crystal X-ray diffraction studies (both monoclinic, P2 (1)/c). The emission spectrum of 1 exhibited the new compound as a red-emitting complex. (C) 2012 Elsevier B. V. All rights reserved.

Abstract  Mesoporous tantalum phosphate was prepared from tantalum tartrate complex and ammonium dihydrogenphosphate, by using hexadecyltrimethylammonium bromide as surfactant, and ulterior calcination at 550 [deg]C. It exhibits a high specific surface area (256 m2 ga1) and strong acidity (1480 I14mol NH3 ga1), and it can be successfully used as solid catalyst in the transesterification of sunflower oil with methanol. With only 5 wt.% of this catalyst in relation to the oil, a 89 wt.% of biodiesel formation was attained at 200 [deg]C and after only 2 h of reaction. The catalyst is very stable and no leaching of tantalum or phosphorus species to the liquid medium was found. Moreover, this acid solid catalyst is able to simultaneously catalyse the esterification of free fatty acids (FFAs) and the transesterification of triglycerides, even in the presence of 9% of FFAs. Its catalytic performance is well maintained after three catalytic cycles, without any treatment and even in the presence of 5 wt.% of water. The use of a co-solvent do not enhanced the biodiesel formation.

Abstract  The objective of this work was to determine the glucose in alcoholic beverages using the simple and reliable glucose oxidase (GOx) biosensor. Glucose oxidase was immobilized on the surface of modified graphite electrode in mixed photocurable polymeric membranes of polyacrylamide (PAA)/polyvinylpyrolidone (PVP), taking advantage of both immobilizations; higher activity due to enzyme entrapment (PVP) and longer life of biosensor due to covalent bonding of enzyme (PAA). The surface of graphite electrode was modified with electrodeposited layer of indium (III) and ruthenium (III) hexacyanoferrate films to get faster electron transfer through the surface layer of the modified electrode. Voltammetric and amperometric measurements were performed under batch conditions. The response of biosensor was measured as a function of selected organic solvents (methanol, ethanol and isopropanol) containing phosphate buffer solution (pH = 6.5) at -100 mV against a reference Hg1Hg(2)Cl(2)13 M KCl electrode. Addition of 10% of methanol and ethanol increased, while higher volume fractions decreased the biosensor response. On the other hand isopropanol (10%) decomposed the photopolymeric membrane. Therefore, the determination of glucose in alcoholic beverages has been performed in phosphate buffer with 10% of ethanol. The linear range was obtained up to 0.8 mM (R-2 = 0.9925) for mixed solvents, as well as phosphate buffer (R-2 = 0.9996). The simple, fast and easy preparation of the biosensor, high activity and long life, if glucose was immobilized in mixed polymeric photocurable membrane, and reasonably accurate glucose determination, make the proposed procedure appropriate for quality control of the alcoholic beverages in mixed solvents. (C) 2011 Elsevier Ltd. All rights reserved.

Abstract  Sulfated zirconia catalysts obtained by employing chlorosulfuric acid show significantly higher activity in the esterification of fatty acids with different alcohols compared with catalysts made using sulfuric acid. The superior performance results from higher sulfur content, larger pores and stronger acid sites. These catalysts are robust and do not leach out sulfonic groups. Catalyst performance depends strongly on the sulfation reagent and the calcination conditions of the intermediate zirconium hydroxide. A series of kinetic experiments was carried out with lauric acid and various alcohols (methanol, 2 -ethylhexanol, propanols and butanols). The new catalysts are ca. five times faster when using primary alcohols independent of the alcohol chain length. When using secondary and tertiary alcohols the reaction rate drops considerably. This is explained by a linear free energy relationship of substituent reactivity. The kinetic investigation shows that chlorosulfated zirconia is suitable as a multiproduct catalyst for manufacturing fatty esters, by employing a catalytic reactive distillation process.

Abstract  Biogenic volatile organic compound (BVOC) emissions come from a variety of sources, including living above-ground foliar biomass and microbial decomposition of dead organic matter at the soil surface (litter and soil organic matter). There are, however, few reports that quantify the contributions of each component. Measurements of emission fluxes are now made above the vegetation canopy, but these include contributions from all sources. BVOC emission models currently include detailed parameterization of the emissions from foliar biomass but do not have an equally descriptive treatment of emissions from litter or other sources. We present here results of laboratory and field experiments to characterize the major parameters that control emissions from litter.Litter emissions are exponentially dependent on temperature. The moisture content of the litter plays a minor role, except during and immediately following rain events. The percentage of carbon readily available for microbial and other decomposition processes decreases with litter age. These 3 variables are combined in a model to explain over 50% of the variance of individual BVOC emission fluxes measured. The modeled results of litter emissions were compared with above-canopy fluxes. Litter emissions constituted less than 1% of above-canopy emissions for all BVOCs measured. A comparison of terpene oil pools in litter and live needles with above-canopy fluxes suggests that there may be another canopy terpene source in addition to needle storage or that some terpene emissions may be light-dependent.Ground enclosure measurements indicated that compensation point concentrations of BVOCs (equilibrium between BVOC emission and deposition) were usually higher than ambient air concentrations at the temperature of the measurements.

Abstract  In this study, a simple one-step method was developed to load small-sized Pt nanoparticles (3.1 +/- 0.3 nm) in large quantities (50 wt %) on aniline- functionalized and reduced graphene oxide (r-fGO). In the process, an ethylene glycol solution and aniline-functionalized moiety play the roles of reducing agent and stabilizer for the Pt nanoparticles, respectively, without damaging the graphite structures of the r-fGO. The Pt nanoparticles loading on the surface of r-fGO with uniform dispersion have a great effect on the electrical conductivity.

Abstract  The adsorption and reactivity of acetic acid on anatase TiO2(101) has been investigated with scanning tunneling microscopy (STM). At low coverage, acetic acid is observed to have a characteristic appearance in STM consistent with a dissociative bidentate binding geometry. At room temperature acetic acid has a relatively strong interaction with the anatase (101) surface and a near-unity sticking probability. When deposited at elevated temperatures (420 K), a saturated coverage displays a partially ordered superstructure with two domains across small regions of the anatase surface. The periodicity of these domains was found to be (2 X 1), again consistent with a bidentate binding geometry of the acetate to two neighboring Ti-5c sites along the [010] direction. Heating the acetate-covered surface to 570 K in ultrahigh vacuum resulted in clean desorption of similar to 90% of the molecules, leaving only a small fraction undesorbed that were mainly situated at the step edges of the anatase. STM tip pulsing of +6 V was also found to desorb acetate molecules from the surface.

Abstract  Measurements of (p, rho ,T) properties of seawater with absolute salinity SA=(31.684, 33.507, 37.372, 37.969, 40.164, 41.825, 44.811, 46.119, 48.600, 50.232, 52.449 and 55.529)gkg-1, temperature T=273.15-468.15K and pressures, p, up to 140MPa are reported with the reproducibility of the density measurements observed to be in the average percent deviation range Delta rho / rho = plus or minus 0.01-0.03%. The measurements are made with a new set up vibration-tube densimeter which is calibrated using double-distilled water (Wagner and Prus, 2002), methanol [(de Reuck and Craven, 1993), (Osada et al., 1999) and (Yokoyama and Uematsu, 2003)] and aqueous NaCl solutions [(Archer, 1992) and (Hilbert, 1979)]. Based on these measurements, an empirical expression for the density of seawater at high salinities has been developed as a function of salinity, pressure and temperature. The results can be used to extend the present equation of state of seawater to higher temperatures for pressure up to 140MPa.