ALBERT

Description: Although catchment storage is an intrinsic control on the rainfall-runoff response of streams, direct measurement remains a major challenge. Coupled models that integrate long-term hydrometric and isotope tracer data are useful tools that can provide insights into the dynamics of catchment storage and the volumes of water involved. In this study, we use a tracer-aided hydrological model to characterize catchment storage as a dynamic control on system function related to streamflow generation, which also allows direct estimation of the non-stationarity of water ages. We show that in a wet Scottish upland catchment dominated by runoff generation from riparian peats (histosols) with high water storage, non-stationarity in water age distributions are only clearly detectable during more extreme wet and dry periods. This is explained by the frequency and longevity of hydrological connectivity and the associated relative importance of flow paths contributing younger or older waters to the stream. Generally, these saturated riparian soils represent large mixing zones that buffer the time variance of water age and integrate catchment-scale partial mixing processes. Although storage simulations depend on model performance, which is influenced by input variability and the degree of isotopic damping in the stream, a longer-term storage analysis of this model indicates a system which is only sensitive to more extreme hydroclimatic variability. This article is protected by copyright. All rights reserved.

Description: 2-Pivaloylpterin, an acylated derivative of the biochemically relevant pterin [2-amino-4-oxo-(3 H )pteridine] heterocyclus, undergoes stepwise metallation by the 1, 1′-bis(diphenylphosphanyl)ferrocene-copper(I) cation, [(dppf)Cu] + . The final product obtained, [Cu 3 (dppf)(μ 2 -dppf)(PP)(PP-H + )] 2 (BF 4 ) 4 , could be structurally characterized to reveal coordinative saturation with binding of central Cu + ions to N 1 ,N 3 ,O 4 ,N 5 ,N 8 and pivaloyl-O donor atoms.

Description: Abstract . Two coordination polymers, namely, {[Cd(cdpc)(hmt)(H 2 O)] · H 2 O} n ( 1 ), and [Mn(Hcdpc) 2 (4, 4′-bpy)(H 2 O)] n ( 2 ), were constructed by synergistic assembly through the mixed-ligand synthetic strategy (H 2 cdpc = 1-carboxymethyl-3, 5-dimethyl-1H-pyrazole-4-carboxylic acid, hmt = hexamethylenetetramine, and 4, 4′-bpy = 4, 4′-dipyridine). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Single X-ray diffraction analysis reveals that complex 1 is a 2D 4-connected sql sheet, and complex 2 is an interesting 1D loop chain. The two complexes are further expanded to 3D supramolecular structure through non-covalent bonds. Besides, luminescent properties of two complexes in the solid state and magnetic property of 2 were also investigated.

Description: The chemical preparation, structure, luminescence, and electronic properties are given for a new potassium holmium cyclotetraphosphate KHoP 4 O 12 , a promising optics material for applications. Single-crystal X-ray diffraction analysis shows that the newly synthesized compound crystallizes in the monoclinic system with space group C 2/ c and Z = 4. [P 4 O 12 ] 4– anionic rings and HoO 8 polyhedra display a three-dimensional (3D) framework by corner-sharing. The ten-coordinated potassium atoms are located in the delimited tunnels. KHoP 4 O 12 exhibits the blue light emission under the excitation of 330 nm. To gain further insights into electronic properties of crystal KHoP 4 O 12 , theoretical calculation based on density functional theory (DFT) was performed using the total-energy code CASTEP with the LDA + U approach. The calculated bandgap with U = 3.0–3.5 eV is in good agreement with the experimental measurement.

Description: The possibility of predicting the droplet size distribution from the particle size distribution was investigated. For that purpose, suspensions of different types of materials were dried in a laboratory-scale spray drier. Drying of suspensions was performed with different sizes of two-fluid nozzles. Droplet size distribution was evaluated from the data obtained for spray drying of bismuth molybdate suspension. The method was validated experimentally with other tested materials. Investigated systems involve processes of drying, crystallization, and coating. The proposed methodology can be applied when nonagglomerated particles, spherical particles, or spherical agglomerates were obtained by spray drying. Spray drying is a unique drying process since formation of solid phase and drying occur simultaneously. Droplet size distribution produced by a two-fluid nozzle during spray drying of bismuth molybdate suspension was evaluated simply from the particle size distribution. The proposed methodology enables prediction of the particle size distribution obtained by spray drying.

Description: The influence of vibration parameters on the segregation phenomenon of a binary mixture in a vibration fluidized bed is investigated. Initially, the mixture composed of spherical balls with different densities but same diameter is in a perfect mixing state in the bed. The motion of particles is simulated based on the discrete element method. The effects of friction coefficient, vibration frequency, amplitudes, and gas velocity are analyzed. The coefficient of segregation to the degree of particle segregation is calculated for different operating conditions. The segregation degree in the vibration fluidized bed is found to be higher than that in the bed without vibration. The curve for the segregation degree exhibits a single peak value which represents the optimal segregation result. The impact of vibration on gas phase- and particle flow is not yet clarified due to the complex motion of particles in vibrated fluidized beds. Discrete particle simulation is used to investigate the segregation behavior of binary mixtures in a fluidized bed. The effect of vibration parameters and suitable operating conditions for segregation, particle distribution, and particle motion are evaluated.

Description: The effects of a turbulence-generating grid on fluid mixing and a passive chemical reaction are experimentally investigated in a liquid shear mixing layer under a nonpremixed condition. The grid is installed at three streamwise locations to find the optimal location to promote the chemical reaction. The results show that the grid generates disturbances at small scales that enhance fluid mixing and the chemical reaction. However, the turbulence intensity and mass diffusion in the mixing layers with the grid decrease rapidly and become even smaller than those in the mixing layer without the grid in a downstream region. Therefore, in the present study, the chemical production is maximized when the grid is installed at where the flow is turning to a developed mixing layer. Installation of a turbulence-generating grid is advantageous to promote fluid mixing and chemical reaction in a free shear flow in which the reactive fluids are introduced under a nonpremixed condition. Special attention is needed regarding the location of the grid to maximize the promotion effect since it could be better to install it in the downstream region rather than the upstream region.

Description: Bubble splitting in 2D gas-solid freely bubbling fluidized beds is experimentally investigated using digital image analysis. The quantitative results can be applied for the development of a new breakage model for bubbly fluidized beds, especially discrete bubble models. The variation of splitting frequency with bubble diameter, new resulting bubble volumes, positions, and also the assumptions of mass and momentum conservation for bubbles after breakage are studied in detail. Small bubbles are found to be more stable than large ones and nearly all mother bubbles split into two almost equally sized daughter bubbles. The momentum of gas bubbles in the vertical direction remains approximately constant after breakage, whereas that of bubbles in the horizontal direction changes with no clear trend. The effect of fluidizing gas velocity in breakage frequency is also examined. The behavior of gas bubbles plays a key role in heat- and mass-transfer operations in fluidized beds. Bubble splitting for Geldart B-type particles under varying conditions was investigated in a pseudo-2D gas-solid fluidized bed by digital image analysis. The quantitative results can facilitate the development of new breakage models for bubbly fluidized beds and are particularly relevant for discrete bubble modeling.

Description: For the application of microreactors in industrial processes, more scaling-up strategies are still required except of the original concept, the numbering-up. A more maneuverable and economic approach, combining both similarity-up and numbering-up, is introduced as an example for an innovative strategy. CFD simulation is also applied to assist analysis and optimization of fluid distribution. Based on this concept, named similarity-up + numbering-up + simulation, a pilot-plant microsieve dispersion minireactor used to proceed the reaction of cyclohexanecarboxylic acid and oleum is designed and tested experimentally. With the contribution of similarity-up, the treating capacity of the core unit is significantly increased. Ten parallel units are integrated to form a correspondingly enhanced capacity of the microreactor which exhibits low pressure drop, stable operating performance, and excellent main product selectivity. For industrial applications of microreactors, more flexible and economic scaling-up strategies are required. A scale-up approach for a microsieve dispersion reactor is proposed, combining similarity-up and numbering-up of the core unit with CFD simulation-based device structure optimization. Low fabrication cost, low pressure drop, and excellent main product selectivity can be achieved by this strategy.

Description: The facile synthesis, molecular structure, and reactivity of [Cu(C 7 H 7 NH 2 )Cl] 4 ( 1 ) towards dioxygen and derivatives is reported. The compound could easily be prepared in good yields by mixing CuCl and benzylamine under inert conditions in dichloromethane. Surprisingly this copper(I) compound, a copper(I) tetramer with Cu I ··· Cu I interactions of 2.89 Å, was formed instead of an expected cubane cluster. Oxidation reactions led to formation of μ-oxido-species as intermediates, however 1 did not show any catalytic activity in the activation of CH bonds. In contrast it turned out that 1 was quite stable towards oxidation. Analogous reactions with CuBr or CuI were different and neither cluster units or polynuclear copper(I) complexes were obtained.

Description: A new design of conjugated heat transfer in double-pass parallel-plate laminar countercurrent operations of power law fluids under wall isoflux was investigated experimentally and theoretically. The analytical solutions were obtained with a superposition model by introducing an eigenfunction expansion in terms of a power series for the homogeneous part and an asymptotic solution for the inhomogeneous part. The influence of the power law index on the average Nusselt numbers with the various design and operating parameters is also delineated. The theoretical predictions of the experimental results are represented graphically. The heat transfer performance was considerably improved when compared with a single-pass parallel-plate heat exchanger (without inserting a solid separator sheet). Suitable adjustments of the solid separator sheet position can effectively enhance the heat transfer efficiencies for such a recycling double-pass device, as compared with the efficiencies of single- and double-pass devices.

Description: The effect of different factors, such as pH of the medium (1.5 〈 pH 〈 4.0; 1 × 10 –4 mol · L –1 〈 [SO 4 2– ] 〈 1 × 10 –1 mol · L –1 ), the concentration of extracting agent, temperature and the type of the solvent, on the extraction of vanadium(V) by trioctylamine was studied. It was shown that the extraction of vanadium(V) by trioctylamine at 25 ± 0.5 °C takes place in the pH range 2.0–3.5 and the extracting complex contains decavanadate anion H 2 V 10 O 28 4– and four molecules of the extracting agent. This allows the reaction of vanadium(V) extraction by trioctylamine to be described by the following equation: 2( R 3 NH) 2 SO 4 + H 2 V 10 O 28 4– ( R 3 NH) 4 H 2 V 10 O 28 + 2SO 4 . The effect of the length of the alkyl chain of alcohol (propyl, butyl, isododecyl alcohol) on the homogeneity of the system V V -TOA-toluene-alcohol was investigated. It was established that the solubility of the extracting complexes of vanadium(V) with trioctylamine can be increased by using isododecyl alcohol C 12 H 25 OH as a modifying agent. It was shown that under optimal conditions in the presence of isododecyl alcohol at temperatures above 25 °C in the pH interval 2.0–3.5 trioctylamine extracts vanadium(V) with a high distribution coefficient (lg D V V 〉 2).

Description: In order to study emulsification phenomena, devices generating well-defined flow conditions are essential. Thus, emulsification of drop collectives under laminar shear flow is commonly performed in cylindrical Couette or Searle devices. In these devices, the flow conditions in the shear gap and in the volume underneath the rotor are often different, which can lead to inhomogeneous product properties and may complicate sample taking. Here, a novel cone-cone shear cell is presented to study emulsification processes. The flow inside the device is examined using numerical simulations. The numerical simulations indicate that simple shear flow is realized all over the sample volume in the cone-cone shear cell. The experimental results show that the drop breakup in the cone-cone shear cell is equivalent to the breakup under simple shear realized in the shear gap of a conventional device, i.e., the Searle device. Critical capillary numbers are calculated from the experimental data and show breakup behavior as predicted by single-drop experiments. Thus, the cone-cone shear cell proved to be suitable to study emulsification mechanisms in simple shear flow. Emulsion-based products are widely used in the food, chemical, and pharmaceutical industries. A novel cone-cone shear cell to study emulsification characteristics is described. The flow conditions inside the shear cell are validated via numerical simulations and experimental results.

Description: Hydrocracking of a bitumen-derived asphaltene over NiMo/ γ -Al 2 O 3 was investigated in a microbatch reactor at varying temperatures. The molar kinetics of asphaltene cracking reaction was examined by fitting the experimental data. Below a defined temperature, the molar reaction showed the first-order kinetic feature while at higher temperatures secondary reactions such as coke formation became significant, causing deviation of the reaction behavior from the proposed first-order kinetic model. Selectivity analysis proved that dominant products varied from gases to liquids to gases with increasing temperature, shifting the dominant reaction from C–S bonds cleavage to C–C bonds cleavage. Catalytic hydrocracking could be a proper choice for asphaltene upgrading but the reaction conditions still need to be optimized. Hydrocracking of a bitumen-derived asphaltene over a NiMo/ γ -Al 2 O 3 catalyst in a microbatch reactor at varying temperatures was analyzed. The molar kinetics of asphaltene cracking reaction was evaluated by fitting the experimental data.

Description: The tetraalkyldigallium(II) compound R 2 Ga–Ga R 2 ( 1 ) [ R = CH(SiMe 3 ) 2 ] reacted with amino and hydroxo functionalized carboxylic acids by retention of the Ga–Ga bond and release of CH 2 (SiMe 3 ) 2 . New heterocyclic or cage-like compounds were formed with three, two, or six Ga–Ga bonds in a single molecule. The latter dodecagallium compounds encapsulated THF or dioxane molecules in their molecular cavities (carcerands), the other compounds have up to six THF molecules coordinated by N–H ··· O hydrogen bonds.

Description: Two different types of metals (Cu and Ni) and the effect of CeO 2 addition to produce a CeO 2 -ZrO 2 co-supporter were investigated through the water-gas shift (WGS) reaction. It was found that the WGS activity could be enhanced with CeO 2 addition. At relatively high temperature, Ni-loaded catalysts exhibited higher CO conversion while Cu-loaded catalysts demonstrated better performance at low temperatures. The stability and yield of the CO 2 and H 2 products of the Cu catalysts were higher than those of the Ni catalysts. These results may be caused by an irreversible adsorption of CO on Ni and the reverse WGS reaction occurring on the Ni catalysts. In situ diffuse-reflection infrared Fourier transform spectroscopy data suggests that the WGS mechanism likely proceeded via formate species. The water-gas shift reaction (WGS), as an alternative way to produce H 2 and convert poisonous CO into CO 2 , was carried out using Cu and Ni loaded onto CeO 2 -ZrO 2 as catalysts. The Ni-loaded catalysts exhibited higher CO conversion at high temperature while the Cu-loaded catalysts performed better at low temperature. The WGS reaction was found to occur via the formation of formate species.

Description: Reduction of chalcogen-rich Pb:Ch (1:2) phases in ethane-1,2-diamine ( en ) by elemental alkali metals results in the formation of solutions of [Pb 2 Ch 3 ] 2– of high purity and abundance. In contrast, application of the same reaction conditions to a binary Bi:Te (1:2) phase yields the mononuclear [BiTe 3 ] 3– anion. Instead of the expected [Tl 2 Te 3 ] 4– or [Tl 2 Te 2 ] 2– anions, analogous reactions with a Tl:Te (1:1) phase end up with a C–C-bond cleavage of the solvent en with formation of a salt of the telluridocyanate (N≡C–Te) – anion. Side reactions of en and elemental cesium are presented and metalate solutions are investigated with NMR spectroscopy.

Description: Seven lanthanide containing strand-like coordination polymers and dimeric complexes were obtained in a reversible reaction from 1, 3-thiazole (thz) and Ln Cl 3 ( Ln = La, Ce, Pr, Nd). The reactions do not require activation and render coordination polymers accessible at room temperature, already. The product constitutions depend on the lanthanide and the thiazole-to-halide ratio. For lanthanum and cerium formation of the coordination polymers 1 ∞ [ Ln Cl 3 (thz) 3 ] · thz as well as dimeric complexes [ Ln 2 Cl 6 (thz) 8 ] · 3thz were observed. For praseodymium and neodymium dimeric complexes were observed with and without non-coordinating thz. Upon heating, the compounds release thiazole under re-formation of Ln Cl 3 , the formation reaction thus being a thermally reversible reaction. Compounds and conversion processes were characterized by temperature dependent X-ray powder and single-crystal X-ray diffraction, in-situ temperature dependent gas phase IR spectroscopy, DTA/TG, and elemental analysis.

Description: Power ultrasound is applied for cooling crystallization to control and modify the particle size and crystal habit of an active pharmaceutical ingredient, phenacetin. Operating parameters including sonication intensity and duration, solution concentration, and cooling rate are studied and compared. With respect to mean particle size, the effect of sonication intensity is most significant. In addition, the crystal habit of recrystallized phenacetin is modified substantially and shows an elliptic shape. Recrystallized phenacetin also provides an enhanced dissolution rate compared with the original sample. These results prove that ultrasonic crystallization is an efficient tool for controlling the solid-state properties of an active pharmaceutical ingredient. Ultrasonic crystallization is a promising process for controlling the different stages of crystallization. Cooling crystallization applying power ultrasound is adopted for recrystallization of a nonsteroidal anti-inflammatory drug, phenacetin. The mean particle size can be managed by adjusting sonication intensity and duration. Phenacetin crystals with a regular crystal habit and an elliptic shape are obtained.

Description: In a variety of reactions in the chemical industry, eggshell catalysts with a thin active layer are applied; they are often crushed for laboratory testing. The destruction of the shell can be avoided by a special reactor design. The presented advanced TEMKIN reactor is a further development of the reactor system for testing eggshell catalysts on the laboratory scale published by Temkin and Kul'kova in 1969. It is suitable for kinetic studies and for the detailed investigation of deactivation processes, as shown on the example of selective hydrogenation of acetylene. The advanced TEMKIN reactor is well suitable for testing of uncrushed industrial eggshell catalysts because of its defined flow pattern and excellent mass and heat transport properties. Because of its simple and robust design, all technical requirements are fulfilled for a fast, competitive, and accurate optimization of prototypes as well as already established catalysts for industrial applications.

Description: A bench-scale submerged membrane bioreactor (SMBR) was employed to treat vegetable oil plant wastewater with complete sludge retention. Treatment performance and membrane fouling of the SMBR were investigated. The system stably removed high amounts of total organic carbon, oil, and ammonia from vegetable oil wastewater and reduced the chemical oxygen demand, demonstrating the great potential of the SMBR in removing pollutants. The membrane fouling layer was not only governed by deposition of organic substances composed of extracellular polymeric substances like proteins, polysaccharides etc., and oil substances but also by inorganic elements. Organic foulants coupled to inorganic precipitation enhanced the formation of a gel layer and triggered severe membrane fouling in the SMBR. Treatment and disposal of vegetable oil wastewaters (VOWs) represents one of the principal problems for vegetable oil producing countries. A bench-scale submerged membrane bioreactor was applied to treat VOWs with complete sludge retention. Treatment performance and membrane fouling were investigated. The experimental results demonstrated the great potential of this membrane bioreactor in removing pollutants.

Description: Adsorption processes are frequently applied to separate traces of hazardous and toxic substances from gas streams. Hence, knowledge of sorption characteristics of these substances on standard adsorbents is essential. Sorption of hexanal and acetaldehyde from a nitrogen gas stream in trace concentrations on activated carbon and ordered mesoporous carbon-based adsorbents (CMK) is studied. A magnetic suspension balance and an attached gaschromatograph-mass spectrometer were used to analyze the sorption process both gravimetrically and spectrometrically. Both types of adsorbents show a higher capacity for hexanal than acetaldehyde. The activated carbon exhibits considerable differences in regard to desorption of hexanal compared to the mesoporous CMK. Information on sorption characteristics of hazardous substances is essential to design separation processes. Adsorption and desorption of the toxic acetaldehyde and the intensely odorous hexanal on activated carbon and periodic mesoporous carbon were studied. Magnetic suspension balances were used to analyze the sorption processes. Both adsorbents exhibit a higher capacity for hexanal than acetaldehyde.

Description: High-solids biomass slurries exhibit non-Newtonian behavior with a yield stress and require high power input for mixing. The goals were to determine the effect of scale and geometry on power number P 0 , and estimate the power for mixing a pretreated biomass slurry in a 3.8 million L hydrolysis reactor of conventional design. A lab-scale computational fluid dynamics model was validated against experimental data and then scaled up. A pitched-blade turbine and A310 hydrofoil were tested for various geometric arrangements. Flow was transitional; laminar and turbulence models resulted in equivalent P 0 which increased with scale. The ratio of impeller diameter to tank diameter affected P 0 for both impellers, but impeller clearance to tank diameter affected P 0 only for the A310. At least 2 MW is required to operate at this scale. High-solids biomass slurries are characterized by non-Newtonian behavior with a yield stress and high power input demand for mixing. A computational fluid dynamics model was developed to predict power requirements of non-Newtonian lignocellulosic slurry in an industrial-scale hydrolysis reactor with conventional mixing impellers. The lab-scale model was validated against experimental data and then scaled up.

Description: The effect of NaCl added in different quantities on thermodynamic properties, granulometric characteristics, and structure of glycine in a crystallization process was investigated. Solubilities of α - and γ -polymorphs in the presence of varying amounts of NaCl were analyzed. In order to examine the impact of the additive on granulometric properties of glycine, crystal morphology was examined by observing crystals under a scanning electron microscope. Crystal size distribution was determined by sieve analysis. By X-ray diffraction analysis, the critical concentration of NaCl at which the structure of glycine changed, could be defined. The purity of obtained polymorphs was confirmed by Fourier transform infrared spectroscopy. Interactions between additives and crystallizing phase influence crystallization processes. Batch-cooling crystallization of glycine with different amounts of added NaCl is described, causing changes in solubility, metastable zone width, supersaturation, final mass of crystals, granulometric properties, and structure. Process conditions for a conversion of α- into a γ- glycine structure are defined.

Description: Cryogenic air separation as the most important part of an integrated gasification combined cycle is a widely used operation unit for producing large quantities of high-purity oxygen and nitrogen. However, cryogenic distillation requires a large amount of energy due to the work needed to compress the air feed. An improved heat-integrated air separation column (HIASC) is proposed. The requirements of high-purity separation in the industrial cryogenic air separation process are achieved. An optimization model of the heat transfer coefficient ( UA ), a key parameter in column structure design and operation, is presented. The optimized UA value is obtained within the accepted value range reported in the international open literature, which ensures the practicability of the improved HIASC. An improved heat-integrated air separation column is proposed. With the new heat-integrated and thermally coupled structure, the pressure of the high-pressure column and the energy consumption decrease significantly compared with the conventional air separation column. The mathematic model and parameter analysis are presented. An optimization model for the heat transfer coefficient is proposed.

Description: Functional mesoporous Mo–SiO 2 materials were synthesized by a one-pot and facile room-temperature procedure, and characterized by X-ray diffraction, TEM, Raman spectroscopy, FT-IR, diffuse reflectance spectra, and BET analysis. The experimental results demonstrated that the mesoporous materials presented a high dispersion of molybdenum species and excellent catalytic activity for the removal of dibenzothiophene (DBT) without organic solvents as extractants. The catalytic performance on different sulfur-containing compounds was also investigated in detail. After recycling for eight times, the removal of the oxidation desulfurization system could still reach high values. GC-MS analysis detected the oxidation product of DBT. A mechanism was proposed for the absorptive oxidation process of sulfur compounds. The removal of sulfur compounds from petroleum is of utmost importance for stringent fuel specifications and environment pollution. Functional mesoporous Mo–SiO 2 materials were synthesized by a facile procedure and were characterized by a high dispersion of molybdenum species and excellent catalytic activity for the removal of dibenzothiophene under mild conditions without organic solvents as extractants.

Description: The level set method is combined with the concentration transformation method to solve the interphase mass transfer process. However, the artificial diffusion generated in the mass transfer convection term across the interface is inevitable, especially when large shape deformation is encountered at high Reynolds numbers. A semi-Lagrangian advection scheme is introduced to overcome this disadvantage. The methyl isobutyl ketone (MIBK)-acetic acid-water system is adopted to study the unsteady mass transport process accompanied with the Marangoni effect of a single deformable drop ascending in the infinite continuous phase. The predicted overall mass transfer coefficients agree with experimental data very well. The configuration of Marangoni convection is revealed and its effect on the interphase mass transfer process is investigated. The solute-induced Marangoni effect on an ascending drop driven by buoyancy is numerically simulated based on the level set method. The semi-Lagrangian convection scheme is introduced to eliminate the artificial diffusion. Compared with literature data, the present algorithm with the semi-Lagrangian convection scheme significantly suppressed the numerical diffusion and achieved much better predictions.

Description: The surface properties of solvent-based (SB) and water-based (WB) coatings and their impact on fouling during convective heat transfer of CaSO 4 solutions were investigated. Experiments demonstrated that the SB coatings had generally better non-adhesive characteristics, especially at higher values of the electron donor component since the deposits could easily be washed away. For the SB coatings, a longer induction period compared to those of untreated surfaces was observed and a significant reduction of the fouling rate could be achieved. Further analysis of surfaces revealed that SB coatings enhanced the acid-base repulsive force and thus reduced the deposit/solid adhesion energy. For the WB coatings, the Liftshitz-van der Waals attractive force plays a decisive role in the adhesion process due to the higher apolar component of the surface energy. Recent technological advances have given impetus in altering surface properties to mitigate fouling of heat transfer surfaces. The attempted coatings in this study demonstrated that they can extend the induction period of the fouling processes of CaSO 4 deposits by four times. This was but mostly due to their higher electron donor component of the surface energy compared to stainless-steel substrate.

Description: The structural and vibrational data for the CF 3 XX CF 3 ( X = O, S, Se, Te) molecules were compared using DFT quantum chemistry calculations. The experimental vibrational frequencies and their assignments to the different normal modes of vibration could be confirmed. The data was also used to define a scaled quantum mechanics force field and sets of derived internal force constants for each molecule. A linear relationship between the experimental X – X bond lengths and the corresponding force constants was found. Additionally, some calculations for the mixed molecule CF 3 SOCF 3 were made.

Description: Ultrasonic hot embossing of polymers is an alternative to reduce fabrication costs of microreactors. An ultrasonic welding machine is used to melt a stack of thermoplastic foils and adapting them to a short-time milled aluminum mold showing the inversed design of the desired microfluidic cavities. Two micromixers were fabricated this way providing a low degree of axial dispersion and pressure loss. Stability analysis is successfully performed for a wide temperature range and high pressure. Mixing of colored aqueous solutions and neutralization reactions are implemented to both systems for defined volume flow rates and optically investigated via microscope. Reaction progress is automatically determined with a MATLAB script by reference to the consequential color change of the neutralization reaction with a color indicator. Typical mixing characteristics are identified for both mixers. Ultrasonic hot embossing of chemically resistant polymers as a simple and cost-effective fabrication method of microstructures and an optical analysis tool for tracing the progress of chemical reactions are introduced and evaluated. The simplicity of the fabrication method itself and good similarities of produced polymer micromixers with conventional ones made of other materials are pointed out.

Description: The existing screening and characterization systems for biocatalysts operate in batch mode, which could make catalyst selection and process development inaccurate when continuous operation mode is required in industry. A significant improvement of an innovative screening system based on miniaturized multiple membrane reactors formerly presented by the author is outlined, which enables continuous feeding of substrates and continuous removal of products. Although the presented screening system was originally designed for homogeneous enzymatic reactions, it can be used without further modifications for continuous catalysis with polymer-bound chemical catalysts or for quasi-homogeneous systems like reverse micelles. Currently available screening and characterization systems for biocatalysis are not sufficiently suitable for process description and scale-up of results to pilot- or full-scale reactors often operated in continuous mode. Hydrolysis of N -acetyl- L -methio-nine served as model reaction for an innovative continuous characterization system, implementing a precise dosing system.

Description: The synthesis of n -butyl levulinate, one of the most important biodiesel additives, by catalytic esterification of biomass-derived levulinic acid (LA) with n -butanol over modified H-ZSM-5 (micro/meso-HZ-5) in a closed-batch system is reported for the first time. The optimization of the reaction conditions such as the reactant molar ratio, the catalyst loading, the reaction time and the temperature was performed in view to maximize the yield of n -butyl levulinate. Micro/meso-HZ-5 was found to be the most efficient catalyst, with 98 % yield of n -butyl levulinate and a reusability for six cycles, which is higher than reported in the literature. A possible catalytic mechanism for the esterification reaction is also proposed. A second-order pseudo-homogeneous model with R 2  〉 0.97 confirmed that the esterification reaction is performed in the kinetic regime due to the high activation energy of 23.84 kJ mol −1 . The modified zeolite catalyst H-ZSM-5 (micro/meso-HZ-5) was used as heterogeneous acid catalyst in the esterification of renewable levulinic acid with n -butanol to produce n -butyl levulinate in a closed system. Micro/meso-HZ-5 turned out to be an efficient catalyst with 98 % yield of n -butyl levulinate and high reusability.

Description: The coordination polymer [Zn(bpdc)(bimb)(H 2 O)] n ( 1 ) [H 2 bpdc = biphenyl-3,4′-di carboxylate, bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene] was constructed under hydrothermal conditions. The structure of complex 1 was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, XRD, IR spectroscopy, and TG analysis. Complex 1 shows an exceptional self-penetrating 4-connected net derived from a threefold interpenetrating 6 3 -hcb subnet. Furthermore, the luminescent property of complex 1 is investigated

Description: The new dithiophosphate anion P 2 S 6 (OEt) 2 2– was obtained from the reaction of commercially available P 4 S 10 with Na 2 S in pyridine, subsequent ethanolysis and isolated as the stable bis(pyridinium) salt 1 . The molecular structure of 1 in the crystal was determined by single-crystal X-ray diffraction and reveals a PSSP dihedral angle of 87.3(1)° within the anion. The compound is a rare representative of a thiodiphosphate anion with a disulfide bridge between the two phosphorus atoms.

Description: The ureates of the alkali metals Na – Cs were synthesized from urea and the metals in liquid ammonia at temperatures below 50 °C. The crystal structures were determined using single-crystal X-ray diffraction. NaCN 2 H 3 O crystallizes in the monoclinic system [ P 2 1 / c , Z = 16, a = 17.529(1) Å, b = 6.4784(5) Å, c = 10.8211(9) Å, β = 96.938(1)°]. All other ureates are orthorhombic, with KCN 2 H 3 O and RbCN 2 H 3 O being isotypic [ Pbca , Z = 8, KCN 2 H 3 O: a = 7.102(4) Å, b = 7.221(4) Å, c = 13.533(8) Å; RbCN 2 H 3 O: a = 7.1973(8) Å, b = 7.3531(8) Å, c = 13.921(2) Å]. CsCN 2 H 3 O adopts a smaller unit cell [ P 2 1 2 1 2 1 , Z = 4, a = 6.3520(3) Å, b = 7.1645(4) Å, c = 9.0911(5) Å]. The ureates of K, Rb, and Cs contain hydrogen-bond networks, the imino nitrogen atom acting as the hydrogen-bond acceptor in CsCN 2 H 3 O. In KCN 2 H 3 O and RbCN 2 H 3 O, however, the carbonyl oxygen atom accepts the hydrogen bonds.

Description: Phosphorus (P) is one of the major limiting nutrient in many freshwater ecosystems. During the last decade, attention has been focused on the fluxes of suspended sediment and particulate P through freshwater drainage systems because of severe eutrophication effects in aquatic ecosystems. Hence, the analysis and prediction of phosphorus and sediment dynamics constitutes an important element for ecological conservation and restoration of freshwater ecosystems. In that sense, the development ofa suitable prediction model is justified and the present work is devoted to the validation and application of a predictive Soluble Reactive Phosphorus (SRP) uptake and sedimentation models, to a real riparian system of the middle Ebro river floodplain. Both models are coupled to a fully distributed 2D shallow water flow numerical model. The SRP uptake model is validated using data from three field experiments. The model predictions show a good accuracy for SRP concentration, where the linear regressions between measured and calculated of the three experiments were significant ( r 2  ≥ 0.62; p  ≤ 0.05), and a Nash-Sutcliffe coefficient (E) that ranged from 0.54 to 0.62. The sedimentation model is validated using field data collected during 2 real flooding events within the same river reach. The comparison between calculated and measured sediment deposition showed a significant linear regression ( p  ≤ 0.05; r 2  = 0.97) and an E that ranged from 0.63 to 0.78. Subsequently, the complete model that includes flow dynamics, solute transport, SRP uptake and sedimentation is used to simulate and analyze floodplain sediment deposition, river nutrient contribution and SRP uptake. According to this analysis, the main SRP uptake process appears to be the sediment sorption. The analysis also reveals the presence of a lateral gradient of hydrological connectivity that decreases with distance from the river, and controls the river matter contribution to the floodplain. This article is protected by copyright. All rights reserved.

Description: The inherent effects of global sea surface temperature (SST) anomalies on hydrological cycle and vegetation cover complicate the structure of tropical climate at the regional scale. Assessing hydrological processes related to climate forcing is important in Central America because it is surrounded by both the Pacific and Atlantic oceans and two continental landmasses. In this study, the use of high-resolution remote sensing imagery in wavelet analysis helps identify nonstationary characteristics of hydrological and ecological responses. The wavelet-based empirical orthogonal function (WEOF) further reflects the nonlinear relationship between the Atlantic and Pacific SST and the greenness of a pristine forested site in Panama, La Amistad International Park. Integrated WEOF and descriptive statistics for data analysis reveal a higher temporal variability in terrestrial precipitation relative to in-situ land surface temperature and its probable effects on the presence of dry periods. Such teleconnection signals of SST were identified as a driving force of decline in tropical forest greenness during dry periods. The results of our remote sensing-based wavelet analysis showed intrannual high frequency and biennial to triennial low frequency signals between enhanced vegetation index (EVI)/precipitation datasets and SST indices in both Atlantic and Pacific oceans. A spatiotemporal priority search further confirmed the importance of the effects of the El Niño-Southern Oscillation (ENSO) over terrestrial responses in the selected study site. Coincidence of the effect of ENSO teleconnection patterns on precipitation and vegetation suggest possible impacts of El Niño-associated droughts in Central America, accompanied by reduced rainfall, especially during the first months of rainy season (June, July and August), and decline in vegetation cover during the dry season (March and April). This article is protected by copyright. All rights reserved.

Description: Chromium tricarbonyl η 6 complexes of 3 cyclacene are considered quantum chemically at the levels of B3LYP/6-31G(d), B3LYP/6-31++G(d, p), B3LYP/LANL2DZ, and RF/6-31G(d, p)//B3LYP/6-31++G(d, p). One of the complexes involves the top ring (A-type) and the other one (B-type) makes use of ring of the acene belt of the cyclacene in the complex formation. Energy calculations reveal that B-type complex is more stable than A-type. Some geometrical and quantum chemical properties were obtained. Additionally, vibrational and UV/Vis spectra of the complexes were produced.

Description: Three mononuclear copper(II) complexes of copper nitrate with 2, 6-bis(pyrazol-1-yl)pyridine ( bPzPy ) and 2, 6-bis(3′,5′-dimethylpyrazol-1-yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO 3 ) 2 ] ( 1 ), [Cu(bPzPy)(H 2 O)(NO 3 ) 2 ] ( 2 ) and [Cu(bdmPzPy)(NO 3 ) 2 ] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X-ray structure analysis of complexes 1 and 2 revealed a five-coordinate copper atom in 1 , whereas 2 contains a six-coordinate (4+2) Cu II ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D-chains in a zipper-like motif.

Description: The organic-inorganic hybrid compounds, [Cu 2 Cl 6 ] 2– ( 1 ), [Fe 2 Cl 6 O] 2– ( 2 ), and [FeCl 4 ] – ( 3 ), based on [(C 8 H 12 NO)(18-crown-6)] + (C 8 H 12 NO = 4-methoxybenzylammonium) supramolecular cations, were synthesized and structurally characterized. Crystal structure analyses and thermal and dielectric studies showed that compounds 1 and 2 have similar crystal packings and undergo reversible phase transitions at 230 K and 358 K, respectively. Compound 3 shows a phase transition at 361 K, though its crystal structure is remarkably different from 1 and 2 . These results indicate that the phase transitions may arise from the [(C 8 H 12 NO)(18-crown-6)] + supramolecular cations. The role of the chlorometalate anions is to tune the crystal packings and thus the phase transition points and types.

Description: This paper evaluates the IBIS land surface model using daily soil moisture data over a three-year period (2005–2007) at a semi-arid site in southeastern Australia, the Stanley catchment, using the Monte-Carlo GLUE approach. The model was satisfactorily calibrated for both the surface 30 cm and full profile 90 cm. However, full-profile calibration was not as good as that for the surface, which results from some deficiencies in the evapotranspiration component in IBIS. Relatively small differences in simulated soil moisture were associated with large discrepancies in the predictions of surface runoff, drainage and evapotranspiration. We conclude that while land surface schemes may be effective at simulating heat fluxes they may be ineffective for prediction of hydrology unless the soil moisture is accurately estimated. Sensitivity analyses indicated that the soil moisture simulations were most sensitive to soil parameters, and the wilting point was the most identifiable parameter. Significant interactions existed between three soils parameters: porosity, saturated hydraulic conductivity and Campbell “b” exponent so they could not be identified independent of each other. There were no significant differences in parameter sensitivity and interaction for different hydroclimatic years. Even though the data record contained a very dry year and another year with a very large rainfall event, this indicated that the soil model could be calibrated without the data needing to explore the extreme range of dry and wet conditions. IBIS was much less sensitive to vegetation parameters. The leaf area index (LAI) could affect the mean of daily soil moisture time series when LAI 〈 1, while the variance of the soil moisture time series was sensitive to LAI 〉 1. IBIS was insensitive to the Jackson rooting parameter, suggesting that the effect of the rooting depth distribution on predictions of hydrology was insignificant. This article is protected by copyright. All rights reserved.

Description: The chemical bonding in the intermetallic compounds ZnPd and ZnPt with the tetragonal CuTi type of structure, and in the chemically related intermetallic compounds ZnNi, ZnCu, ZnAg, and ZnAu with the cubic CsCl type of structure, is examined applying the electron localizability approach. The analysis of the chemical bonding reveals charge transfer from zinc to the transition metal ( TM ), in line with the respective electronegativities. While in ZnNi, ZnCu, and ZnAg as well as ZnPd and ZnPt the Zn– TM interactions are described by multi-center bonding and ionic interactions, mainly ionic interactions are found in the intermetallic compound ZnAu. Going from ZnNi over ZnPd to ZnPt, a gradual change from isotropic to more and more anisotropic distribution of the atomic interactions is detected, resulting in a more pronounced tetragonal distortion.

Description: Two new three-dimensional frameworks with zeolite-like channels were prepared in the presence of 1,6-diaminohexane. Cu 1.5 (H 3 N–(CH 2 ) 6 –NH 3 ) 0.5 [C 6 H 2 (COO) 4 ] · 5H 2 O ( 1 ) crystallizes in the triclinic space group P with a = 772.56(7), b = 1110.36(7), c = 1111.98(8) pm, α = 98.720(7)°, β = 108.246(9)°, and γ = 95.559(7)°. Cu 2 (H 3 N–(CH 2 ) 6 –NH 3 ) 0.5 (OH)[C 6 H 2 (COO) 4 ] · 3H 2 O ( 2 ) crystallizes in the monoclinic space group P2 / c with a = 1159.34(11), b = 1059.44(7), c = 1582.2(2) pm, and β = 106.130(11)°. The Cu 2+ coordination polyhedra are connected by [C 6 H 2 (COO) 4 ] 4– anions to yield three-dimensional frameworks with wide centrosymmetric channel-like voids. Complex 1 reveals voids extending along [100] with diagonals of 900 pm and 300 pm, whereas in complex 2 the diagonal of the nearly rectangular crossection of the channels extending parallel to [001] is 900 pm. The negative excess charges of the frameworks are compensated by [H 3 N–(CH 2 ) 6 –NH 3 ] 2+ cations, which occupy the voids along with water molecules. The [H 3 N–(CH 2 ) 6 –NH 3 ] 2+ cations are not connected to Cu 2+ and have served as templates.

Description: The molecular alumosiloxanes (O-SiPh 2 -O-SiPh 2 -O) 3 Al 2 and (O-SiPh 2 -O-SiPh 2 -O) 4 [Al(OH)] 4 react either with water in diethyl ether, or with 1,4-butane-diol to form the new macro-cyclic compounds Al 6 (OH) 8 (O-SiPh 2 -O-SiPh 2 -O) 4 (O-SiPh 2 -O-SiPh 2 -OH) 2 ·6H 2 O ( 2 ) or Al 6 (OH) 8 (O-SiPh 2 -O-SiPh 2 -O) 4 (O-SiPh 2 -O-SiPh 2 -O-CH 2 –CH 2 –CH 2 –CH 2 –OH) 2 ( 3 ). As shown by single crystal structure analyses, both compounds 2 and 3 have a center of symmetry, resemble each other structurally and display in their center an [Al 2 (OH) 8 ] 2– unit, which is coordinated in a similar fashion to a 24-membered [Al 4 (O-SiPh 2 -O-SiPh 2 -O) 4 ] 2+ cycle branched at two aluminum atoms displaying either two (O-SiPh 2 -O-SiPh 2 -OH) ( 2 ) or two (O-SiPh 2 -O-SiPh 2 -O-CH 2 –CH 2 –CH 2 –CH 2 –OH) ( 3 ) arms. The [Al 2 (OH) 8 ] 2– groups are connected to the cycles through oxygen atoms of their hydroxide groups which link to the aluminum atoms of the ring (of the four aluminum atoms in the ring two have a double contact and two a single). Parallel to this bonding, the aluminum atoms of [Al 2 (OH) 8 ] 2– have either a water molecule in their coordination sphere, which is incorporated in a complex hydrogen bridged network including the silanol function ( 2 ), or are bonded to the –CH 2 -OH group of the siloxane-alcohol arm of the cycle ( 3 ). The aluminum atoms of the central part are in both compounds in the centers of two distorted edge sharing oxygen octahedra (mean Al–O = 1.881(7) Å ( 2 ), 1.893(7) Å ( 3 )), while the other four aluminum atoms display a tetrahedral oxygen environment (Al–O = 1.752(8) Å ( 2 ), 1.754(8) Å ( 3 )). Whereas all hydroxy groups of the [Al 2 (OH) 8 ] 2– unit in 2 are engaged in hydrogen bonding including further water molecules which make part of the network, the [Al 2 (OH) 8 ] 2– unit in 3 shows fewer hydrogen bridges. We have here a rare example of the same chemical species in a more hydrophilic and a less hydrophilic surrounding. This allows a detailed study of the impact of secondary hydrogen bonding on the structure.

Description: The mechanochemical synthesis offers an easy access to obtain alkaline earth metal terephthalates M (C 8 H 4 O 4 ) · n H 2 O ( M = Ca, Sr, Ba). In the presented study we describe for the first time the mechanochemical synthesis of powders of Ca(C 8 H 4 O 4 ) · 3H 2 O, Ca(C 8 H 4 O 4 ), Sr(C 8 H 4 O 4 ) · H 2 O, and Ba(C 8 H 4 O 4 ), which so far were only synthesized as single crystals from aqueous solutions or by reactions in an autoclave. Furthermore, a new hydrate Ba(C 8 H 4 O 4 ) · 2(1.5)H 2 O, not described so far in the literature, was prepared. All compounds were characterized by X-ray powder diffraction, thermal analysis, elemental analysis, FT-IR, and MAS NMR spectroscopic measurements.

Description: Over the past few decades ground water has become an essential commodity due to increased demand as a result of growing population, industrialization, urbanization etc. The water supply situation is expected to become more severe in the future because of continued unsustainable water use and projected change in hydro-meteorological parameters due to climate change. This study is based on the integrated approach of Remote Sensing (RS), Geographical Information System (GIS) and Multi-Criteria Decision Making (MCDM) techniques to determine the most important contributing factors that affect the ground water resources and to delineate the ground water potential zones. Ten thematic layers viz. geomorphology, geology, soil, topographic elevation (DEM), land use/land cover, drainage density, lineament density, proximity of surface water bodies, surface temperature and post-monsoon ground water depth were considered for the present study. These thematic layers were selected for ground water prospecting based on literature, discussion with the experts of Central Ground Water Board (CGWB), Government of India, field observations, geophysical investigation and multivariate techniques. The thematic layers and their features were assigned suitable weights on the Saaty's scale according to their relative significance for ground water occurrence. The assigned weights of the layers and their features were normalized by using Analytic Hierarchy Process (AHP) and eigenvector method. Finally, the selected thematic maps were integrated using weighted linear combination method to create the final ground water potential zone map. The final output map shows different zones of ground water potential, viz., very good (16%), good (35%), moderate (28%) low (17%) and very low (2.1%). The ground water potential zone map was finally validated using the discharge and ground water depth data from 28 and 98 pumping wells respectively which showed good correlation. This article is protected by copyright. All rights reserved.

Description: Bank erosion is the main source of suspended sediment (SS) and diffuse total phosphorus (TP) in many lowland catchments. This study compared a physically based sediment routing method (Physical method), which distinguishes between stream bed and bank erosion, with the original sediment routing method (Original method) within the Soil and Water Assessment Tool (SWAT) version 2009, for simulating SS and TP losses from a lowland catchment. A SWAT model was set up for the lowland River Odense catchment in Denmark and calibrated against observed stream flow and phosphate (PO 4 ) loads. Based on an initial calibration of hydrological and PO 4 parameters, the SWAT model with the Original method (Original model) and the SWAT model with the Physical method (Physical model) were calibrated separately against observed SS and TP loads. The SWAT model simulated daily stream flow well, but underestimated PO 4 loads. The Physical model simulated daily SS and TP better than the Original model. The simulated contribution of bank erosion to SS in the Physical model (99%) was close to the estimated contribution from in-situ erosion measurements (90-94%). Compared with the Original method, the Physical method is not only more conceptually correct, but also improves model performance. This article is protected by copyright. All rights reserved.

Description: This paper focuses on surface-subsurface water exchange in a steep coarse-bedded stream with step-pool morphology. We use both flume experiments and numerical modelling to investigate the influence of stream discharge, channel slope and sediment hydraulic conductivity on hyporheic exchange. The model step-pool reach, whose topography is scaled from a natural river, consists of 3 step-pool units with 0.1 m step heights, discharges ranging between base and over bankfull flows (scaled values of 0.3-4.5 L/s) and slopes of 4 and 8%. Results indicate that the deepest hyporheic flow occurs with the steeper slope and at moderate discharges and downwelling fluxes at the base of steps are highest at the largest stream discharges. In contrast to pool-riffle morphology, these findings show that steep slopes cause deeper surface-subsurface exchanges than gentle slopes. Numerical simulation results show that the portion of the hyporheic zone influenced by surface water temperature increases with sediment hydraulic conductivity. These experiments and numerical simulations emphasize the importance of topography, sediment permeability and roughness elements along the channel surface in governing the locations and magnitude of downwelling fluxes and hyporheic exchange. Our results show that hyporheic zones in these steep streams are thicker than previously expected by extending the results from streams with pool-riffle bed forms. This article is protected by copyright. All rights reserved.

Description: Robot in Laboratory. Copyright: Max Tactic – Fotolia.com.

Description: The objective of this analysis is to demonstrate the feasibility of using a composite L2 SMOS soil moisture product for determining drought conditions by taking advantage of its spatial and temporal resolution. The work investigates the potential relationships between soil moisture anomalies and two drought indices, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), both calculated on a ten-day basis. As the two drought indices can be applied to different time scales for precipitation series, the influence of time scale on the drought definition is also studied. The anomalies were calculated both for the in situ soil moisture by REMEDHUS (Soil Moisture Measurement Stations Network, Spain) and from the SMOS L2 soil moisture product. In general, in situ anomalies exhibit higher correlation coefficients for the drought indices than those of SMOS, except for the shortest time scale. As expected, the short-term remotely sensed anomalies have a high response to precipitation events. This effect may be due to the greater sensitivity of SMOS data to rainfall, as well as to the spatial averaged nature of its observations. The optimal time scale was one month for the SMOS values and ranged between 30 and 50 days for the in situ values. The use of evapotranspiration in the calculation of the indices did not improve the description of the anomalies. The relationship between indices and soil moisture conditions provides encouraging results. Indeed, this method generates preliminary but valuable insights for future satellite products. This article is protected by copyright. All rights reserved.

Description: The cage compound Ba 3 Ge 16 Ir 4 crystallizes with the Ba 3 Ge 16 Rh 4 type of crystal structure, which represents a hierarchical derivative of the BaAl 4 type. The crystal structure [Pearson symbol tI 46, space group I 4/ mmm ; a = 6.5312(2) Å, c = 22.2845(6) Å] was refined from single-crystal X-ray diffraction data. The phase was obtained after 10 d at 910 °C with small impurities of clathrate-I, BaGe 7 Ir 2 and α-Ge remaining at the grain boundaries. Ba 3 Ge 16 Ir 4 is a Pauli-paramagnetic metal, which becomes superconducting below T c = 5.1 K. Electronic structure and analysis of the chemical bonding were performed based on density functional theory calculations. The physical properties are discussed in comparison to the isotypic phase Ba 3 Ge 16 Rh 4 .

Description: Remote estimation of river discharge from river width variations is an intriguing method for gauging rivers without conventional measurements. Entirely cloud-free imagery of an entire river reach is often rare, but partial coverage is more frequent. Discharge is estimated from spatially discontinuous imagery via construction of multiple width-discharge rating curves within a 62 km reach of the Tanana River, Alaska. The resulting discharge error is as low as 6.7% RMSE. Imagery covering 〈20% of the study reach can be used. This article is protected by copyright. All rights reserved.

Description: Reports of abruptly declining flows of Canada's Athabasca River have prompted concern because this large, free-flowing river could be representative for northern North America, provides water for the massive Athabasca oil-sands projects, and flows to the extensive and biodiverse Peace-Athabasca, Slave and Mackenzie River deltas. To investigate historic hydrology along the river and its major tributaries we expanded the time series with interpolations for short data gaps; calculations of annual discharges from early, summer-only records; and by splicing records across sequential hydrometric gauges. These produced composite, century-long records (1913 to 2011) and trend detection with linear Pearson correlation provided similar outcomes to non-parametric Kendall τ−b tests. These revealed that the mountain and foothills reaches displayed slight increases in winter discharges versus larger declines in summer discharges, and consequently declining annual flows (~0.16%/yr at Hinton; p 〈 0.01). Conversely, with contrasting boreal contributions, the Athabasca River at Athabasca displayed no overall trend in monthly or annual flows, but there was correspondence with the Pacific Decadal Oscillation (PDO) that contributed to a temporary flow decline from 1970 to 2000. These findings from century-long records contrast with interpretations from numerous shorter-term studies, and emphasize the need for sufficient time series for hydrologic trend analyses. For Northern Hemisphere rivers, the study interval should be at least 80 years to span two PDO cycles and dampen the influence from phase transitions. Most prior trend analyses considered only a few decades and this weakens interpretations of the hydrologic consequences of climate change. This article is protected by copyright. All rights reserved.

Description: Four zinc(II) complexes, namely, Zn(Hdmpz) 2 (L1) 2 ( 1 ) (Hdmpz = 3, 5-dimethylpyrazole, HL1 = trichloroacetic acid), Zn(Hdmpz) 2 (L2) 2 ( 2 ) (HL2 = 2, 4-dichlorophenoxyacetic acid), [Zn 2 (μ-dmpz) 2 (Hdmpz) 2 (L3) 2 ] ( 3 ) (HL3 = 1-naphthylacetic acid), and [Zn(Hdmpz) 2 (L4) 2 ] · H 2 O ( 4 ) (HL4 = indole-3-acetic acid) were prepared and structurally characterized by different techniques including elemental analysis, IR spectroscopy, TG, and single-crystal X-ray diffraction analysis. The complexes display 2D to 3D structures with tetrahedral to pentagonal coordination around the central zinc atom. The X-ray studies suggested that 1 , 2 , and 4 are mononuclear complexes, whereas 3 is a centrosymmetric dinuclear complex. The pyrazole ligand is coordinated in both terminal as well as a bridging fashion in the dinuclear moiety but the pyrazole ligand in the mononuclear complexes is coordinated only in monodentate terminal fashion with its neutral N group. The carboxylate groups behave as monodentate ligands in 1 – 3 , whereas the carboxylate in 4 functioned as both monodentate and chelating bidentate ligand. On the basis of X-ray crystallographic study the rich intra- and intermolecular weak interactions such as classical hydrogen bonds, C–H ··· O, CH 3 ··· O, CH–Cl, Cl–Cl, C–H ··· π, CH 2 –π, CH 3 –π, O–π, and π–π are analyzed. All these noncovalent interactions help to assemble the discrete complexes into high-dimensional ordered superamolecular structures.

Description: Acetate trinuclear metal complexes of Zn II and Co II with the potentially tridentate Schiff base ligand, having mixed phenolate, imine, and pyridine donor groups, HL, were synthesized. The complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV/Vis spectroscopy, and magnetic measurements. Crystal structures of [ M 3 L 2 (OAc) 4 ] ( M = Zn II , Co II ) complexes, were also determined. The X-ray structures show the presence of trinuclear complexes with metal ions joined by phenolate and acetate bridging groups. The ligands coordinate to the metal ions through the imine nitrogen and their corresponding attached pyridyl and phenolate groups. The coordination environment for the metal ions is completed by bridging acetate anions to generate an octahedral coordination arrangement for the Co II complex and mixed distorted, bipyramidal trigonal and octahedral arrangements for the Zn II complex.

Description: Recent studies have suggested that the hydrologic connectivity of northern headwater catchments is likely controlled by antecedent moisture conditions and land cover patterns. A water storage model ( EWS ), based on water levels ( WLs ), specific yield ( Sy ) and surface elevation ( SE ) changes was compared to a basic water budget of a small, boreal, patterned fen (13 ha) during the ice-free period. Results showed that the EWS model reproduced well storage variations derived from the water budget. These results suggest that storage variations can be properly represented by the fluctuations of WLs when we consider the heterogeneous soil properties. However, storage deviations occurred at the daily scale and could be explained by a lack of information on water retention in unsaturated layers, canopy interceptions and preferential flows. Despite the significant impact of SE changes on the different peatland cover storage budgets (strings and lawns), using Sy mean values had low impact on storage estimations. This can be explained by the large proportion of pools and high WLs throughout the fen. At the fen scale, high storage in the pools seemed to reduce the Sy difference between strings and lawns. The results of this study provide new insights about the complex hydrological behaviour of northern catchments and allow for conceiving new hydrological modeling perspectives. This article is protected by copyright. All rights reserved.

Description: Starting from a flexible tri-carboxylic acid ligand H 3 L {H 3 L = 2,4,6-tris[(4′-carboxyphenoxy)methyl]-1,3,5-trimethylbenzene}, a 3D metal-organic framework [Zn(HL)(H 2 O)] n ( 1 ) and a 2D polymeric layered solid {[(CH 3 ) 2 NH 2 )] 2 [Cd 2 L 2 (DMA) 2 ]} n ( 2 ) were hydrothermally synthesized. The complexes were characterized by elemental analyses, FT-IR spectroscopy, TGA, and single-crystal X-ray diffraction. The X-ray structural analyses reveal that the complex 1 is an example of a doubly interpenetrated 3D helical MOF with mutually entwined right- and left-handed helices to form an overall racemic framework. Complex 2 is made up of fourfold interwoven 2D nets in the solid state.

Description: Oxidovanadium(IV) complexes, [VO(acac)(L)Cl] ( 1 ), [VO(cur)(L)Cl] ( 2 ), and [VO(scur)(L)Cl] ( 3 ) {acac = acetylacetonate, cur = curcumin monoanion, scur = diglucosylcurcumin monoanion, L = 11-(9-acridinyl)dipyrido[3, 2-a:2',3'-c]phenazine (acdppz)}, were prepared and characterized. The complexes are non-electrolytic in DMF and 1:1 electrolytic in aqueous DMF. The one-electron paramagnetic complexes showed a d-d band near 725 nm in aqueous DMF and green emission near 520 nm in aqueous DMSO. The complexes exhibited an irreversible V IV /V III redox response near –0.85 V versus SCE in aqueous DMF. The complexes showed good binding strengths to calf thymus DNA ( K b : 3.1 × 10 5 –9.6 × 10 5 M –1 ) and efficient pUC19 DNA photocleavage activity in red light of 705 and 785 nm by singlet oxygen ( 1 O 2 ) pathway. Complexes 1 and 2 exhibited significant photocytotoxicity (IC 50 : 0.1–1.0 μM) in visible light (400–700 nm) with low dark toxicity (IC 50 : 〉20 μM) in HeLa and HaCaT cells. Complex 3 was cytotoxic in both light and dark. DNA ladder formation experiments indicated cell death via apoptotic pathway. Confocal microscopy done with 1 and 2 revealed primarily cytosolic localization of the complexes with significant presence of the complex in the mitochondria as evidenced from the imaging data using mitotracker red.

Description: The coordination polymer [Cd(HL)(BPDA)] n · n H 2 O ( 1 ) based on 3-(5-(pyridin-4-yl)-1 H -1,2,4-triazol-3-yl)pyridine (HL) and 1,1′-biphenyl-4,4′-dicarboxylic acid (H 2 BPDA) was hydrothermally synthesized and characterized by single-crystal X-ray diffraction, XRPD, IR spectroscopy, and elemental analysis. The asymmetric unit of compound 1 consists of one crystallographically independent Cd II ion, one HL ligand, “two half” BPDA 2– ligand, and one lattice water molecule. There are two crystallographically different BDPA 2– moieties, but each of them is placed in a symmetry element. The BPDA 2– ligands and Cd II ions connected to2D sheet, and the 2D sheets are connected to a 3D MOF by the HL ligands. Each dimeric Cd II unit links six nearest neighbors through the BPDA 2– and HL ligands, and the dimeric Cd II units are centrosymmetric. Two parallel HL ligands connect two dimeric Cd II units, generating long Cd2–HL–Cd2–HL rings, also centrosymmetric. So we can define the dimeric Cd II unit as a 6-connected node. Thus, the 3D structure can be described as a threefold parallel interpenetrated bsn beta-Sn topology. In addition, the optical properties of compound 1 and the free ligand H L were investigated.

Description: The 4-connected dmp -type cadmium(II)-isonicotinate framework [Cd(isonic) 2 (H 2 O)] n · n (DMA) ( 1 ) (isonic = isonicotinate, DMA = N , N ′-dimethylacetamide) was obtained by the solvothermal reactions of Cd(NO 3 ) 2 and isonicotinic acid (Hisonic). Compound 1 features a 3D porous framework with the opened channels occupied by the lattice DMA molecules. Thermal analysis reveals that such framework remains much stable after removal the free DMA molecules. CO 2 adsorption measurement shows that such framework exhibits notable CO 2 adsorption behavior.

Description: The reaction of the basic bismuth nitrate [Bi 6 O 4 (OH) 4 (NO 3 ) 6 ] · H 2 O with either thiosalicylic acid or sulfuric acid gave the novel bismuth hydrogen sulfate [Bi 2 (SO 4 ) 2 (dmso) 8 ](HSO 4 ) 2 ( 1 ) (DMSO = dimethyl sulfoxide). The formation of sulfate ions is observed in the presence of either Bi 3+ or [Bi 6 O 4 (OH) 4 ] 6+ indicating bismuth-induced oxidation of thiosalicylic acid. Compound 1 was characterized by elemental analysis, infrared spectroscopy, thermal analysis (TGA), and temperature dependent in situ X-ray powder diffraction. Crystals suitable for single crystal structure analysis were obtained from a DMSO/acetone solution. The title compound 1 crystallizes in the triclinic space group P with the following lattice parameters: a = 9.5240(4) Å, b = 9.9535(4) Å, c = 12.6620(5) Å, α = 109.943(4)°, β = 93.952(3)°, γ = 102.868(3)°, V = 1086.17(8) Å 3 , and Z = 1. Analysis of the thermally induced decomposition revealed the formation of Bi 2 O(SO 4 ) 2 and Bi 2 O 2 (SO 4 ) as intermediate products and Bi 28 O 32 (SO 4 ) 10 as final product.

Description: Recently, the synthesis of hexadentate ligands based on N , N ′-bis-(2,2′-bipyridine-6-ylmethyl)-2,2′-biphenylenediamine ( 1a – d ) and the corresponding iron(II) complexes ( 3a – d ) was reported by our group. In this contribution we present the synthesis of the analogous cobalt(II) complexes 4a – d . Together with the iron(II) complex the electrochemical behavior of the complexes 3 and 4 was investigated by cyclic voltammetry (CV). The aminomethyl substructure was identified as the main source of ligand degradation caused by chemical oxidation with air. Upon exposure to air the amine group in complexes 3 and 4 is oxidized to imine and even amide groups. Some examples ( 8 , 9 ) of the oxidation products were characterized by X-ray structure analysis. In order to increase the robustness of the Fe II and Co II complexes towards oxidation, the ligand scaffold of 1a was modified by N -methylation of the amino group yielding the tertiary amine 2 . The corresponding iron(II) and cobalt(II) complexes employing 2 as ligand were synthesized {[Fe( 2 )][PF 6 ] 2 ( 5 ), [Co( 2 )][PF 6 ] 2 ( 6 )} and fully characterized, their redox behavior and spin-state was investigated by CV and Evans' method. It was found, that the introduced N -methyl group leads to a substantial anodic shift of the M II – M III redox potential and the stabilization of Fe II and Co II high-spin state. By means of X-ray structure analysis these effects could be explained by repulsive steric effects of the methyl group.

Description: The intermetallic compounds Y 2 RuB 6 , Y 2 ReB 6 , Y 2 RhSi 3 , YRh 2 Si, and YPdSi were synthesized from the elements by arc-melting and subsequent annealing in sealed silica ampoules. The samples were studied by X-ray diffraction on powders. The structures of Y 2 RuB 6 and Y 2 RhSi 3 were refined from single crystal diffraction data: Y 2 ReB 6 type, Pbam , a = 916.3(2) pm, b = 1150.3(3) pm, c = 364.37(9) pm, wR 2 = 0.1056, 942 F 2 values, 38 variables for Y 2 RuB 6 and Er 2 RhSi 3 type, a = 812.6(2), c = 787.2(1) pm, wR 2 = 0.0682, 369 F 2 values, 17 variables for Y 2 RhSi 3 . The five compounds are characterized by two or three (YPdSi), crystallographically independent yttrium sites, which were all well resolved in 89 Y solid state NMR spectra. The NMR signal shifts were correlated with the density of states of the s electrons at the Fermi level, resulting in a non-ambiguous assignment of the NMR signals to the various sites in the crystal structures.

Description: The title complexes were obtained by reactions of [(η 5 -C 5 H 5 )(CO) 2 Fe] – , [(η 5 -C 5 H 4 CH 3 )(CO) 2 Fe] – , [Re(CO) 5 ] – , or [Mn(CO) 5 ] – with the mixed anhydride from the respective pyridine carboxylic acid and pivalic acid or with isonicotinic acid chloride, and were characterized by spectroscopic data and elemental analysis.

Description: The N -(2, 6-diisopropylphenyl)- N ′-benzoylthiourea ligand (shown as L ) ( 1 ) was synthesized and characterized. Reactions of 1 with CuCl 2 and CuBr 2 afforded the monomeric L 2 CuCl ( 2 ) and dimeric [ L BrCu(μ- L )] 2 ( 3 ), respectively, due to the reduction of Cu II . The reaction of 1 and CuCl gave the same product L 2 CuCl ( 2 ), while the treatment of 1 with CuBr led to the formation of a rare example of adamantanoid cage ( L Cu) 2 (μ- L ) 2 Cu 2 (μ-Br) 4 ( 4 ) containing enantiomeric couple. The product of 1 and CuI was found to be dimeric [ L ICu(μ- L )] 2 ( 5 ), which is isomorphous to 3 . All compounds obtained were fully characterized by elemental analysis, IR, 1 H NMR and 13 C NMR spectroscopy, and single-crystal X-ray diffraction.

Description: Thermodynamic data for gaseous SiF 2 and SiCl 2 known from literature show that these binary subhalides are formed nearly quantitatively at 1376 °C and 1076 °C, respectively, as products of the reaction of elemental silicon with SiF 4 or SiCl 4 at 1 × 10 –2 mbar. Applying the co-condensation technique SiF 2 as well as SiCl 2 can be trapped at –196 °C and prepared in synthetic scale. Herein, first analysis of metastable SiF 2 and SiCl 2 solutions are presented, showing that SiF 2 is more reactive than SiCl 2 leading to compounds of low boiling point of so far unknown composition. The metastable SiCl 2 solution can be used as a SiCl 2 source, which is shown by the trapping reaction with Idipp [Idipp = 1, 3-bis(2, 6- i Pr 2 -C 6 H 3 )imidazol-2-ylidene] leading to Idipp-SiCl 2 . The reactivity of the solution might be fine-tuned by changing the donor opening the door for further applications.

Description: Minor changes to seasonal air temperature and precipitation can have a substantial impact on the availability of water resources within large watersheds. Two such watersheds, the north-flowing Mackenzie and east-flowing Saskatchewan Basins have been identified as highly vulnerable to such changes, and, therefore, selected for study as part of the Climatic Redistribution of western Canadian Water Resources (CROCWR) project. CROCWR aims to evaluate spatial and temporal changes to water resource distribution through the analysis of a suite of hydroclimatic and streamflow variables. As part of this analysis, dominant summer (May-Oct) circulation patterns at 500-hPa for 1950-2011 are identified using the method of Self-Organizing Maps (SOM). Surface climate variables associated with these patterns are then identified, including both daily air temperature and precipitation, and seasonal Standardized Precipitation-Evapotranspiration Index (SPEI) values. Statistical methods are applied to assess the relationships between dominant circulation patterns and the Southern Oscillation Index (SOI) and Pacific Decadal Oscillation (PDO). Results indicate that mid-summer (Jul-Aug) is dominated by a split-flow blocking pattern, resulting in cool (warm), wet (dry) conditions in the southern (northern) portion of the study area. By contrast, the shoulder season (May and Oct) is dominated by a trough of low-pressure over the North Pacific Ocean. The frequency of weak split-flow blocking is higher during positive SOI and negative PDO, while ridging over the western continent is more frequent during negative SOI and positive PDO. Results from this analysis increase our knowledge of processes controlling the distribution of summer water resources in western Canada. This article is protected by copyright. All rights reserved.

Description: Lithium transition metal silicates, Li 2 M SiO 4 ( M = Fe, Mn, Co), have attracted much interest as positive electrodes for Li-ion batteries due to their high theoretical capacities and their rich crystal chemistry. Low (β) and high (γ) temperature forms of these tetrahedral structures differ in the ordering/distribution of cations within tetrahedral sites of an hcp based packing of oxygen. We have carried out VT powder neutron and X-ray diffraction on Li 2 M SiO 4 ( M = Fe, Mn) to characterize the rich polymorphism observed across the Li 2 M SiO 4 ( M = Fe, Mn) system as a function of temperature. For Li 2 FeSiO 4 below 500 °C a β II phase was observed with slight Li/Fe disorder. Above this temperature there was a sluggish transition to the γ s phase, which was observed up to ca. 820 °C, with the γ II polymorph seen at highest temperatures. Excellent agreement with phases obtained by quenching was observed, except that the γ phases exhibit a statistical distribution of Li/Fe, in contrast to the well-ordered structures of quenched phases. The Li 2 MnSiO 4 polymorphism is less complex, the β II phase is stable from room temperature to 750 °C, at which temperature it transforms to the γ structure with disordered Li/Mn.

Description: Ag@Au core-shell nanoparticles were synthesized by using a fluorescent dipeptide β -Ala-Trp in water medium and at a room temperature without using any external reducing and stabilizing agents. The shell thickness of gold in core-shell Ag@Au nanoparticles has also been varied by changing the concentration of the gold(III) precursor keeping the other conditions same. The optical property of these core-shell nanoparticles varies with the shell thickness. Interestingly, these core-shell nanoparticles exhibit good catalytic property for the reduction of nitrophenols to aminophenols and nitroanilines to aminoanilines. A series of nitrophenol and nitroaniline compounds were taken as substrates for reduction. Moreover, this core-shell nanoparticle displays remarkable difference in catalytic property for reduction of nitro group with the variation of shell thickness. This catalyst (Ag@Au core-shell nanoparticle) can also be recycled for several times indicating its reusability.

Description: Two coordination polymers, namely {[Mn(2,4′-bpdc)(bimb)(H 2 O) 0.5 ] · 0.5H 2 O} n ( 1 ) and [Mn(4,4′-bpdc)(bimb)] n · 2.5H 2 O ( 2 ) [2,4′-bpdc = biphenyl-2,4′-dicarboxylate, 4,4′-bpdc = biphenyl-4,4′-dicarboxylate, and bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene], were hydrothermally synthesized by reactions of manganese(II) salt with the rigid ligand 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene and isomeric biphenyl dicarboxylate ligands. Complex 1 has an unusual 6-connected three-dimensional (3D) architecture with point symbol (4 4 .6 11 ). Complex 2 has also a 3D structure with two-interpenetrated pcu topology with point symbol (4 12 .6 3 ). Structural comparisons show that the positions of the carboxylate groups in the ligand backbone play an important role in governing the structural topologies of these complexes.

Description: Polyethersulfone (PES) was blended with poly( D,L -lactide) (PDLLA) to prepare asymmetric membranes using the phase inversion method. The effects of the blend ratios and poly(ethylene glycol) (PEG) as additive on the membrane structure, properties, and performance were investigated. The membranes were characterized by contact angle determination, scanning electron microscopy, porosity measurement, thermogravimetric analysis, degradation tests in compost, and dynamic tests for pure water flux and bakery product wastewater treatment. PES and PEG slightly reduced the membrane contact angle. Increasing the PDLLA concentration in the blend membranes enhanced the membrane degradation in compost and also the membrane porosity. The permeate flux of the membranes was improved, but the rejection of pollution indices did not change noticeably. Porous membranes have been widely applied in the fields of dialysis, clarification, and purification. The composition of membranes prepared by blending polyethersulfone with poly( D,L -lactide) (PDLLA) affected their characteristics. Increases in the concentrations of PDLLA and the additive poly(ethylene glycol) led to more porous structures, causing higher fluxes.

Description: The separation efficiency of a pilot-scale zigzag apparatus is investigated numerically using computational fluid dynamics simulations and discrete particle modeling in a coupled manner. The effects of various process variables, like particle size and air flow velocity, and of turbulence models were analyzed. The resulting changes concerning the process performance expressed by separation function and sharpness are discussed. Moreover, the residence time distribution was found to differ for fine and coarse particle discharges. Small particles are easily carried away by the fluid and respond immediately to almost every change in flow velocity. Therefore, they are affected by vortices, which increase their residence times compared to bigger particles. Zigzag air classifiers are superior to simple sieves for the separation of particles and are used in many industrial processes. The separation efficiency of a pilot-scale zigzag apparatus is studied using combined computational fluid dynamics simulations and discrete particle modeling. The process performance is discussed with respect to the chosen modeling approach and the operating conditions.

Description: Little research has examined whether forests reduce stream water eutrophication in agricultural areas during spring snowmelt periods. This study evaluated the role of forests in ameliorating deteriorated stream water quality in agricultural areas, including pasture, during snowmelt periods. Temporal variation in stream water quality at a mixed land-use basin (565 ha: pasture 13%, forestry 87%), northern Japan, was monitored for 7 years. Synoptic stream water sampling was also conducted at 16 sites across a wide range of forest and agricultural areas in a basin (18.3 km 2 ) in spring, summer, and fall. Atmospheric nitrogen (N) and phosphorus (P) deposition were measured for 4 years. The results showed that concentration pulses of nitrate (NO 3 – ), organic N (ON), and total P (TP) in stream water were observed when discharge increased during spring snowmelt. Their concentrations were high when silicate concentrations were low, suggesting surface water exported from pasture largely contributed to stream water pollution during snowmelt. Atmospheric N and P deposition (4.1 kg N ha –1 y –1 ; 0.09 kg P ha –1 y –1 , respectively) was too low to affect the background concentrations of N and P in streams from forested areas. Reduction of eutrophication caused by nutrients from pasture was mainly due to dilution by water containing low concentrations of N and P exported from forested areas, while in-stream reduction were not dominant processes. Results indicate that forests have a limited capacity to reduce the concentration pulses of N and P in stream water during snowmelt in this study basin. This article is protected by copyright. All rights reserved.

Description: The semirigid exo -bidentate ligand 1, 4-bis{[(2′-picolylaminoformyl)phenoxyl]methyl}-2, 5-bismethylbenzene (L) was designed, synthesized, and used as building blocks for constructing luminescent lanthanide polymers. Two new lanthanide coordination polymers were characterized by elemental analysis, X-ray diffraction analysis, and IR spectroscopy. The coordination polymers exhibit the metal-to-ligand molar ratio of 1:1 and the semirigid exo -bidentate ligand bridges lanthanide nitrates forming a zigzag chain, which further interconnected to three dimensional supramolecular structure in aid of cooperative C–H ··· O hydrogen bonds. The luminescence properties of the europium(III) complex are discussed in detail.

Description: In NLDAS-2 Noah simulation, the NLDAS team introduced an intermediate “fix” to constrain the surface exchange coefficient when the atmospheric boundary layer is stable. In the current NLDAS-2 Noah version, this fix is used for all stable cases including snow-free grid cells. In this study, we simply apply this fix to the grid cells in which both stable atmospheric boundary layer and snow exist simultaneously, excluding the snow-free grid cells as we recognize that the fix in NLDAS-2 is too strong. We conduct a 31-year (1979-2009) NLDAS-2 Noah interim (Noah-I) run, and use observed streamflow, evapotranspiration, land surface temperature, soil temperature, and ground heat flux to evaluate the results, including comparisons with the original NLDAS-2 Noah run. The results show that Noah-I has the same performance as NLDAS-2 Noah for snow water equivalent; however, Noah-I significantly improved the simulation of other hydrometeorological products as noted above when compared to NLDAS-2 Noah and the observations. This simple modification is being included in the next Noah version used in NLDAS. The hydrometeorological products from the improved NLDAS-2 Noah-I are being staged on the NCEP public server. This article is protected by copyright. All rights reserved.

Description: Large-scale watershed modelling presents a unique challenge in terms of physiographic and climatological heterogeneity and spatially varied hydrologic responses. In particular, the spatial variability in hydrologic processes may introduce a high degree of uncertainty in the modelling of a large watershed. This study assessed the uncertainties in annual/seasonal streamflow and annual peak flow simulations with respect to selection of climate data and model parameter sets for the Variable Infiltration Capacity (VIC) model of the Athabasca River Basin (ARB) in Alberta, Canada. Two high-resolution gridded climate data sets over the 1979 to 2010 period, and six different model parameter sets calibrated corresponding to different time periods and various hydrologic patterns, were employed to quantify the uncertainty in VIC simulations. Moreover, the possibility of an ensemble approach to predict hydrologic responses in the ARB has been investigated. The results indicated that stramflow simulations near the headwater and along the Athabasca River mainsteam have high uncertainty corresponding to selection of climate data mainly due to greater difference of precipitation between the two climate data sets, whereas sub-basin stations at low-elevations were more sensitive to the selection of parameter set for interflow-dominated runoff cycle. All stations showed higher uncertainty corresponding to the selection of parameter set for annual peak flows. In addition, this study confirmed that the ensemble means can provide more accurate and consistent hydrologic information for the low-elevation area where higher internal variability exists. This article is protected by copyright. All rights reserved.

Description: Multilayer covers are widely accepted reclamation designs in the oil sands region of northern Alberta, Canada, with an ultimate goal of revegetating to species characteristic of predisturbance native plant communities. To determine the optimal depth of reclamation material required to reclaim overburden shale from an oil sands mine, an evaluation was made of the long-term performance of six reclamation soil cover depths all placed over overburden. The measured soil water contents from different cover thicknesses at South Bison Hills located at the Syncrude Mine site north of Fort McMurray, Alberta were used to calibrate and validate a dual-porosity model in HYDRUS-1D. The calibrated and validated model was then used to evaluate the influence of cover thickness and climatic variability on plant available water for forest growth. The frequency distributions of actual transpiration (T r ) for six cover treatments with a range of leaf area index (LAI) cases were developed. These T r frequency distributions were then modified by coupling T r and LAI. The modified frequency distributions for annual T r for the six simulated cover thickness highlight the strong non-linearity between the distribution of T r over a long-term (60 year) climate cycle in that incremental increases in cover thickness do not produce proportional increases in T r . The results indicated that, once the cover thickness exceeds 100 cm, there is little incremental increase in the median value of T r over the 60 year climate cycle. This article is protected by copyright. All rights reserved.

Description: Within peatland ecosystems small deviations in surface elevation result in microforms that differ in depth to water-table, plant type and rate of biogeochemical cycling, possibly leading to differences in peat physical and hydrological properties that could feed back to whole ecosystem hydrological and biogeochemical function. However, hydrological parameters for peatland microforms have not been quantified. This study determined bulk density, pore size distribution and saturated hydraulic conductivity (K sat ) at hummocks and hollows of four, Sphagnum -dominated Canadian peatlands. Study sites included both a bog and poor fen in each of Alberta and Quebec allowing for investigation of differences in peat hydrophysical properties between microforms across a range of Sphagnum -dominated peatlands. Hydraulic conductivity was determined in the laboratory on peat from the surface (0.03-0.08 m) and the saturated zone (0.20 m below the local water-table position). Peatland type, climate region, microform and depth of peat were all significant descriptors of variation in K sat . Deeper peat was less conductive than surface peat. Hummocks generally had higher K sat than hollows at both surface and saturated zones, although differences between microforms varied between sites. Differences in K sat between samples were correlated with bulk density, von Post humification and macroporosity. These results indicate that there are microtopographical differences in peat hydrophysical properties; however, the strong decline in K sat with depth indicates that differences in the local water-table, resulting in a change in depth of water flow, is likely a stronger control on local K sat than microform type. This article is protected by copyright. All rights reserved.

Description: A regional, or pooled, approach to frequency analysis is explored in the context of the estimation of rainfall quantiles required for the formation of Intensity-Duration-Frequency (IDF) curves. Resampling experiments are used, in conjunction with two rainfall data sets with long record lengths, to explore the merits of a pooled approach to the estimation of extreme rainfall quantiles. The width of the 95% confidence interval for quantile estimates is used as the primary basis to evaluate the relative merits of pooled and single site estimates of rainfall quantiles. Recommendations are formulated for applying the regional approach to frequency analysis and these recommendations are used in the application of the regional approach to 40 sites with IDF data in southern Ontario, Canada. The results demonstrate that the regional approach is preferred to single site analysis for estimating extreme rainfall quantiles for conditions and data availability commonly encountered in practice. This article is protected by copyright. All rights reserved.

Description: Integrated river basin models should provide a spatially distributed representation of basin hydrology and transport processes to allow for spatially implementing specific management and conservation measures. To accomplish this, the Soil and Water Assessment Tool (SWAT) was modified by integrating a landscape routing model to simulate water flow across discretized routing units. This paper presents a grid-based version of the SWAT landscape model that has been developed to enhance the spatial representation of hydrology and transport processes. The modified model uses a new flow separation index that considers topographic features and soil properties to capture channel and landscape flow processes related to specific landscape positions. The resulting model is spatially fully distributed and includes surface, lateral, and groundwater fluxes in each grid cell of the watershed. Furthermore it more closely represents the spatially heterogeneous distributed flow and transport processes in a watershed. The model was calibrated and validated for the Little River Watershed (LRW) near Tifton, Georgia (USA). Water balance simulations as well as 30 the spatial distribution of surface runoff, subsurface flow and evapotranspiration are examined. Model results indicate that groundwater flow is the dominant landscape process in the LRW. Results are promising and satisfactory output was obtained with the presented grid-based SWAT landscape model. Nash-Sutcliffe model efficiencies for daily stream flow were 0.59 and 0.63 for calibration and validation periods and the model reasonably simulates the impact of the landscape position on surface runoff, subsurface flow and evapotranspiration. Additional revision of the model will likely be necessary to adequately represent temporal variations of transport and flow processes in a watershed. This article is protected by copyright. All rights reserved.

Description: Direct sediment inputs from forest roads at stream crossings are a major concern for water quality and aquatic habitat. Legacy road-stream crossing approaches, or the section of road leading to the stream, may have poor water and grade control upon reopening, thus increasing the potential for negative impacts to water quality. Rainfall simulation experiments were conducted on the entire running surface area associated with six reopened stream crossing approaches in the southwestern Virginia Piedmont physiographic region, USA. Event-based surface runoff and associated total suspended solids (TSS) concentrations were compared among a succession of gravel surfacing treatments that represented increasing intensities of best management practice (BMP) implementation. The three treatments were No Gravel (10-19% cover), Low Gravel (34-60% cover), and High Gravel (50-99% cover). Increased field hydraulic conductivity was associated with maximized surface cover, and ranged from 7.2 to 41.6, 11.9 to 46.3, and 16.0 to 58.6 mm h -1 , respectively, for the No Gravel, Low Gravel, and High Gravel treatments. Median TSS concentration of surface runoff for the No Gravel treatment (2.84 g L -1 ) was greater than Low Gravel (1.10 g L -1 ) and High Gravel (0.82 g L -1 ) by factors of 2.6 and 3.5, respectively. Stream crossing approaches with 90-99% surface cover had TSS concentrations below 1 g L -1 . Reducing the length of road segments that drain directly to the stream can reduce the costs associated with gravel surfacing. This research demonstrates that judicious and low-cost BMPs can ameliorate poor water control and soil erosion associated with reopening legacy roads. This article is protected by copyright. All rights reserved.

Description: In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes using a particle size analyzer and of sludge dewaterability based on the capillary suction time (CST) test were carried out. Synthetic raw water had small floc sizes, and synthetic domestic wastewater had both larger median floc sizes and a better correlation between sludge dewaterability and median floc sizes. The floc size distribution results showed that synthetic raw water is associated with a narrow particle size distribution. In comparison, synthetic domestic wastewater produced a wider distribution. However, the CST values were similar for both waters. Compared to synthetic wastewater, natural wastewater had the largest distribution with generally larger particle sizes. In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes and sludge dewaterability tests were carried out. The particle distribution results show that synthetic raw water is associated with a very narrow range of particles. In comparison, synthetic domestic wastewater produced a larger distribution. The capillary suction times were similar.

Description: The direct-ignition technology of an entrained-flow coal-water slurry gasifier with hot-oxygen burner (HOB) is presented. Experimental tests were carried out using diesel oil and coal-water slurry in a bench-scale entrained-flow opposed multi-burner (OMB) gasifier. Using a CCD camera equipped with high-temperature endoscope, flame images inside the gasifier were recorded and subsequently processed. The results show that the HOB diesel flame is more stable than the normal two-channel burner flame typically used. Entrained-flow coal-water slurry gasifiers can start up using the HOB directly without a higher preheated wall temperature. An HOB can potentially save gasifier preheating time and operation costs and enables a wide range of future applications. Entrained-flow gasification offers one of the cleanest ways to obtain energy from coal. The direct-ignition technology of an entrained-flow coal-water slurry gasifier with a new type of hot-oxygen burner (HOB) was extensively studied to prove the feasibility of the gasifier startup with this setup. The HOB permits to effectively decrease the gasifier preheating time and the system operation costs.

Description: Different approaches were analyzed to combine the tuneable micropore structure of carbide-derived carbons with a foam-like secondary porosity. The resulting structured catalyst supports were characterized in detail and applied in the model reaction of ethene hydrogenation. Preparation methods studied were dip-coating using polytetrafluoroethylene as binder on cellular metal structures, a chemical vapor deposition coating of the metal structures with thin carbide layers and subsequent conversion to carbide-derived carbon, and the partial or full conversion of carbide foams to carbon/carbide composites. For the binder method, optimal parameters for stable slurry preparation as well as for calcination of the slurry were obtained. It could further be demonstrated that the conversion of carbide foams into carbon/carbide composites leads to an appreciation between decreasing mechanical strength and increasing specific surface area. Structured catalysts are advantageous to conventional fixed-bed systems. Carbide-derived carbons with tuneable microporous structure were combined with a foamlike catalyst structure. The three preparation methods studied resulted in highly active catalysts. Optimal conditions for the easy-to-apply dip-coating method to stabilize the slurry for successful coating were determined and evaluated.

Description: An opposed multi-burner (OMB) entrained-flow gasifier with coal water slurry feeding is developed by the East China University of Science and Technology. A 3D model is employed to numerically simulate the gas flow field, motion of char particles, and distributions of temperature and gaseous components in an OMB gasifier and in a conceptual two-stage gasifier modified from the OMB gasifier (TS-OMB gasifier). Results show that the TS-OMB gasifier produces higher concentration and productivity of the effective gases (CO+H 2 ) with a slightly higher carbon conversion than the OMB gasifier. The reasons for the differences between these two types of gasifier are discussed by means of numerical simulation. This information is valuable for guiding the design of an advanced OMB gasifier. With an increasing demand for syngas, entrained-flow gasifiers for coal conversion are installed at the fastest pace due to advantages such as low pollutant emission. Simulations of the gas component distribution, amongst other key factors, in an opposed multi-burner (OMB) gasifier and modified two-stage OMB gasifier were compared. The results are valuable for future design of an advanced OMB gasifier.

Description: The following study discusses the synthesis of macroporous glass beads, featuring variable pore sizes, and their application as starting material for a double templating route according to the nanocasting principle. In the first step, the initial porous glass was filled with the carbon precursor, a mesophase pitch, which after the subsequent carbonization and dissolution of the glass matrix results in an inverse macroporous carbon replica. Afterwards, the carbon beads were filled with amorphous silica by a typical sol-gel-process. The next step can be divided into two phases. The silica gel phase was first “structured” inside the macropores of the inverse carbon replica by converting it into an ordered mesoporous phase via pseudomorphic transformation. This process demanded alkaline conditions and a surfactant, that finally converts the silica into hierarchically structured beads with the dimension and the pores of the initial glass and MCM-41 pores inside the walls. The final step comprised the template removal via calcination. The obtained materials were characterized by mercury intrusion, nitrogen adsorption, scanning electron microscopy, x-ray powder diffraction and particle size analysis. In comparison to the previously reported approaches, the new method allows a higher flexibility in the texture properties of the resulting hierarchically structured materials including a variable ratio between ordered mesopores and additional macropores by parallel control of the total porosity and wall thickness in the starting porous glass.

Description: New periodic mesoporous organosilicas were synthesized using [bis(triethoxysilyl)vinyl]aniline (BTEVA) and [bis(triethoxysilyl)vinyl]benzene (BTEVB) as precursors and by functionalizing the BTEVA PMO with aminopropyl groups. All PMO materials showed a high degree of hexagonal order in the respective P-XRDs as well as high surface areas with narrow pore size distributions. The PMOs together with activated carbon were investigated with regards to their hexanal adsorption capacity in a gravimetric apparatus with an attached GC-MS. For the amine PMOs two different regions during adsorption were found. In the first region loadings in the range of 30 wt% were reached by a fast adsorption process. In the second region the loading reached 50 wt% but with slower kinetics. In desorption experiments up to 150 °C the loading decreased from 50 wt% to 30 wt%, where an equilibrium state was observed. With GC-MS and NMR the first region could be assigned to a chemisorption process, where the hexanal forms an imine group with the amine function in a Schiff base reaction. The subsequent second region can be assigned to weaker and thus reversible physisorption. The total capacity (first and second region) is substantially higher for the amine PMOs than for the activated carbon. Due to the chemical bonding in the chemisorption process, the desorption behavior is completely different: compared to the activated carbon the bonding of hexanal is much stronger for the amine PMOs.

Description: The cover picture shows a section of the crystal structure of the coordination polymer Cu 1.5 (H 3 N-(CH 2 ) 6 -NH 3 ) 0.5 [C 6 H 2 (COO) 4 ]·5H 2 O( 1 ), which features channel-like voids accommodating hexane-1,6-diammonium cations that compensate for the negative charge of the three-dimensional framework. A space-filling view of the framework is inserted. The compound can be dehydrated to a trihydrate and rehydrated to the starting composition retaining the crystal structure. Cu 2 (H 3 N-(CH 2 ) 6 -NH 3 ) 0.5 (OH)[C 6 H 2 (COO) 4 ]·3H 2 O ( 2 ) has a similar framework structure with channels of different dimensions accommodating hexane-1,6-diammonium cations as well. The different compounds have been obtained from aqueous solution by employing the same method, however, at different temperatures. More details are discussed in the article by R. Köferstein and C. Robl on page 310ff.

Description: Groundwater modeling has emerged as a powerful tool to develop a sustainable management plan for efficient groundwater utilization and protection of this vital resource. This study deals with the development of five hybrid artificial neural network (ANN) models and their critical assessment for simulating spatio-temporal fluctuations of groundwater in an alluvial aquifer system. Unlike past studies, in this study, all the relevant input variables having significant influence on groundwater have been considered and the hybrid ANN technique (ANN-cum-Genetic Algorithm) has been used to simulate groundwater levels at 17 sites over the study area. The parameters of the ANN models were optimized using Genetic Algorithm (GA) optimization technique. The predictive ability of the five hybrid ANN models developed for each of the 17 sites was evaluated using six goodness-of-fit criteria and graphical indicators, together with adequate uncertainty analyses. The analysis of the results of this study revealed that the MLP-LM model is the most efficient in predicting monthly groundwater levels at almost all the 17 sites, while the RBF model is the least efficient. The GA technique was found to be superior to the commonly used trial-and-error method for determining optimal ANN architecture and internal parameters. Of the goodness-of-fit statistics used in this study, only RMSE, r 2 and NSE were found to be more powerful and useful in assessing the performance of the ANN models. It can be concluded that the hybrid ANN modeling approach can be effectively used for predicting spaio-temporal fluctuations of groundwater at basin or sub-basin scales. This article is protected by copyright. All rights reserved.

Description: Phosphorus (P) loss from agricultural watersheds has long been a critical water quality problem, the control of which has been the focus of considerable research and investment. Preventing P loss depends on accurately representing the hydrological and chemical processes governing P mobilization and transport. The Soil and Water Assessment Tool (SWAT) is a watershed model commonly used to predict runoff and non-point source pollution transport. SWAT simulates runoff employing either the curve number ( CN ) or Green and Ampt methods, both assume infiltration excess runoff, although shallow soils underlain by a restricting layer commonly generate saturation excess runoff from variable source areas (VSA). In this study, we compared traditional SWAT to a re-conceptualized version, SWAT-VSA, which represents VSA hydrology, in a complex agricultural watershed in east central Pennsylvania. The objectives of this research were to provide further evidence of SWAT-VSA's integrated and distributed predictive capabilities against measured surface runoff and stream P loads and to highlight the model's ability to drive sub-field management of P. Thus, we relied on a detailed field management database to parameterize the models. SWAT and SWAT-VSA predicted discharge similarly well (daily Nash-Sutcliffe Efficiencies of 0.61 and 0.66, respectively), but SWAT-VSA outperformed SWAT in predicting P export from the watershed. SWAT estimated lower P loss (0.0 - 0.25 kg ha -1 ) from agricultural fields than SWAT-VSA (0.0 - 1.0+ kg ha -1 ), which also identified critical source areas - those areas generating large runoff and P losses at the sub field level. These results support the use of SWAT-VSA in predicting watershed-scale P losses and identifying critical source areas of P loss in landscapes with VSA hydrology. This article is protected by copyright. All rights reserved.

Description: This article presents results of mercury in surface waters from Hunza River basin, Northern Areas, Pakistan. Small-scale gold mining activities along Hunza and Gilgit rivers are long known to be discharging mercury in the amalgamation and roasting processes. Previous studies reported high mercury concentrations in soils close to mining operations as well as serious health problems for miners. However, none of the studies have focused on the level of contamination in aqueous environments. This is the first study on the investigation of source and fate of sediment and river-borne mercury in Hunza River. Samples collected near panning sites showed higher mercury concentrations than critical levels established by the U.S. Environmental Protection Agency. The observed dissolved mercury concentrations ranged from 5.10 to 25.25 ng/L, whereas particulate-bound mercury ranged from 4.85 to 154.62 ng/L. Particulate phase mercury corresponded to more than 75% of the total observed mercury concentrations for all of the sampled rivers. Thus, suspended sediments represented the major pathway of the riverine mercury transport. A mass balance calculation suggested a 48.6 g/km 2 of annual mercury flux into Hunza River basin. The samples collected from the most affected river, Shimsal River, averaged to have 108 ng/L total mercury concentration. This number was close to the average soil mercury data from PMDC (2001) of 151 ng/L. The dominant source of contamination was shown to be the leaching of large quantities of mercury from the Hg-rich sediment and flood plain soil into the rivers rather than the direct release from mining activities. Significant decrease in both dissolved and particulate-bound mercury concentration downstream of Attabad Lake suggested that mercury is being accumulated or consumed in the lake. Although minimization or elimination of mercury loses from mining process seems important for the wellbeing of the miners, preventing remobilization of accumulated mercury is equally important in mercury control in this region. This article is protected by copyright. All rights reserved.

Description: Perovskite-type LaVO 2.78 N 0.10 powder was synthesized by thermal ammonolysis of the oxide precursor LaVO 4 . By X-ray, neutron, and electron diffraction an orthorhombic crystal structure with space group Pnma was identified. XANES spectra showed that the oxidation state of vanadium changes from 5+ in LaVO 4 to approximately 3+ in LaVO 2.78 N 0.10 . The temperature dependence of the electrical conductivity revealed an Arrhenius-type behavior with an activation energy of 0.103 eV in the temperature range of 119–302 K indicating that the conduction process is thermally activated band transition. Based on the positive Seebeck coefficient, holes were identified as the dominant charge carriers in the temperature range of 100–302 K. Both the Seebeck coefficient and the thermal conductivity showed an anomaly at 138 K, which is attributed to the Néel temperature for antiferromagnetic ordering according to magnetic susceptibility measurements.