Local wind patterns for modeling renewable energy systems by means of cluster analysis techniques

A method based on cluster analysis techniques is proposed in order to obtain representative local wind patterns. Modeling renewable energy systems, in an accurate way which strongly depends on wind loads, requires reliable data to analyze their response and evaluate their performance. Otherwise poor agreement with the models may be obtained. In a case study for La Paz, Baja California Sur, Mexico, four different wind patterns were obtained from a one-year data set recorded at 10-min intervals.     

Factors controlling flavors binding constants to cyclodextrins and their applications in foods

The binding constants of 14 different flavors (Maltol, Furaneol, Vanillin, Methyl Cinnamate, Cineole, Citral, Menthol, Geraniol, Camphor, Nootkatone, Eugenol, p-vinil Guayacol and Limonene) to cyclodextrins (α-cyclodextrin and β-cyclodextrin) have been determined by an UV–Vis spectrophotometric technique. In all cases the binding constant of flavors to β-cyclodextrin are bigger than the corresponding one to α-cyclodextrin. This fact is due to the different size of cyclodextrin cavity. As well as, a relationship between log P of each flavor and the binding constants was found, proving that the driving force for host–guest complex formation is hydrophobic/hydrophilic interactions.     

Feasibility study for the installation of HVAC for a spa by means of energy recovery from thermal water—Part II: Energy analysis

The use of a low temperature geothermal spring together with the heat energy still contained in waste water from the different therapy systems installed in a spa (shower, jets, bathrooms, jacuzzis, pools, ventilation processes) can significantly reduce the operating and maintenance costs of the installation. This covers part of the air conditioning needs of the building and of the heating of thermal water to the appropriate temperature for therapeutic use.In the first part of the study, an analysis of the spring's situation was made, calculating the thermal water needs and presenting the consumption according to the operation schedule on different types of day. In this way, the contribution the spring was capable of giving was compared and the evolution of the thermal water in the tanks was studied. In the second part, the climatic conditions that the spa should meet are studied, along with the loads that it should support, the energy reclaimed from the different heat focuses and the repercussions on the final solution.     

Polycyclic aromatic hydrocarbons in smoke from different woods and their transfer during traditional smoking into chorizo sausages with collagen and tripe casings

Polycyclic aromatic hydrocarbons (PAHs), at least those with high molecular mass, are classified as probable human carcinogens by the US Environmental Protection Agency. The importance of the material used to generate smoke is indicated by the attention that the European Union is paying to list the wood that can be used to produce smoking flavour agents. The paper examines the dependence on the nature of the wood used for smoking on the formation of eight PAHs (selected as markers of PAHs) and transfer of these PAHs into traditional Spanish smoked chorizo sausages with collagen and tripe casings. The results showed that the kind of combustion performed on different materials seriously affected the PAH levels in the smoke generated. Ignition and firing of the material with a flame compared with heating produced more PAHs in the smoke. The levels of PAHs found in the meat and in the collagen and tripe casings of the smoked chorizo samples suggest that the collagen-based casings behave as a better barrier to PAHs.     

General model to build awnings and external walls with optimum shading interaction

A general model is proposed to optimize the shading interaction between an awning and an external wall that project shadows on the facade of a construction. The original method was presented by the authors in Renewable Energy 28 (2003): 111, for a particular shading proposal. They emphasize the advantage of a one-dimensional approach to solve the problem of this interaction, analyzing the shadows projected by these elements from a side view. The generalized method, presented in this paper, is useful for architects to design shelter projects with more alternatives in the use of such shading devices. The general model also permits study and evaluation of any strategy chosen by the builder to shadow a facade, with an emphasis on windowpane shading, through graphical outputs of the solar performance.     

Effects of a chemical company fire on the occurrence of polycyclic aromatic hydrocarbons in plant foods

On Friday, September 1, 2006, the facilities of a chemicals distributor in the Spanish town of Caldas de Reis, were almost completely destroyed as a result of a fire. Comprehensive liquid chromatography-fluorescence detection (LC-FD) analyses were performed on plant foods to determine the toxic impact of this kind of accident on population. PAHs from a polluted atmosphere are generally transferred to plants by particle-phase deposition on the waxy leaf cuticle or by uptake in the gas phase through stomata. PAH levels in all samples were not alarming (total PAHs were below 4.240 ng/g) and the PAH profiles were similar, with the exception of peppers, in all vegetal materials (5-to-4 rings ratio of 1–2), suggesting the similarity in source type (the fire). PAH concentrations in plants were related to their surface exposed to air, indicating that the contribution of soil/water PAHs to plants (aerial part) accumulation was insignificant.     

Occurrence of fungicide and insecticide residues in trade samples of leafy vegetables

The aim of this work was to report on a total of 23 fungicides and insecticides residues in 75 green and leafy vegetables (Swiss chards, Spinaches and Lettuces) collected from Ourense (NW Spain) by Spring 2007. The pesticides in the study samples were extracted with acetonitrile; the extracts were then cleaned-up by solid-phase extraction and concentrated before determination by PTV (Programmable Temperature Vaporization Injector) – GC-ITMS. Use of analyte protectants mixtures provided the best results in terms of effective compensation for matrix-induced enhancement effect. Pesticide residues were determined above the maxima residue limits (MRL) in 15 of the 75 analyzed samples, with a total of 18 violations of the MRL (three of the samples did not fulfil with two different pesticide MRL). The highest concentrations of fungicides were found in lettuce (procymidone, 12 mg/kg) and the highest concentrations of insecticides were found in Swiss chard (cypermethrin, 6 mg/kg). More positives for fungicides were detected and at larger concentrations than insecticides, especially for lettuces. Accumulation of pesticides in lettuces is higher than for the other leafy vegetables. The findings of this study pointed to the following recommendation: the need for a monitoring program for residues of iprodione and procymidone, together with cypermethrin, in food crops at the national level.     

Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks: The case of squaramide

A well-established strategy to synthesize heterogeneous,metal-organic framework(MOF)catalysts that exhibit nanoconfinement effects,and specific pores with highly-localized catalytic sites,is to use organic linkers containing organocatalytic centers.Here,we report that by combining this linker approach with reticular chemistry,and exploiting three-dimensioanl(3D)MOF-structural data from the Cambridge Structural Database,we have designed four heterogeneous MOF-based catalysts for standard organic transformations.These programmable MOFs are isoreticular versions of pcu IRMOF-16,feu UiO-68 and pillared-pcu SNU-8X,the three most common topologies of MOFs built from the organic linker p.p'-terphenyldicarboxylic acid(tpdc).To synthesize the four squaramide-based MOFs,we designed and synthesized a linker,4,4’-((3,4-dioxocyclobut-1-ene-1,2-diyl)bis(azanedyil))dibenzoic acid(Sq_tpdc),which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers.Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena.Therefore,the four MOFs share the same organocatalytic squaramide moiety,but confine it within distinct pore environments.We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations:a Friedel-Crafts alkylation and an epoxide ring-opening.Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences.     

Metal-organic Frameworks Incorporating Multiple Metal Elements

The obtaining of materials incorporating multiple metal elements is of interest because the combination of various metal cations results in the achievement of new and enhanced properties. Metal-organic frameworks (MOFs) offer a suitable platform to combine multiple metal elements due to their modular nature and highly controllable structure. The incorporation of various metal elements into MOFs might be accomplished by following different synthetic approaches, which in turn determine the way in which the various metal elements are arranged in the framework. In this contribution, we will overview the formation of multi-metal MOFs by the introduction of new metal sites in the organic linkers, or in the inorganic secondary building units through cation exchange process, or one-pot synthesis.     

Efficacy of new commercial formulations to control downy mildew and dissipation of their active fungicides in wine after good agricultural practices

BACKGROUND: The efficacy of common fungicides to control downy mildew (Plasmopara viticola) in vines decreases when the same commercial formulations are applied over several years. For this reason, new commercial formulations (containing new fungicides) have to offer to grape‐growers to increase the efficacy of antifungal treatments. The efficacy of five new commercial formulations (Cabrio Top, Equation Pro, Fantic M, Mikal Premium and Fobeci) to control downy mildew in an experimental vineyard producing white grapes (Vitis vinifera cv. Godello) was studied. All these products have in common a new fungicide (pyraclostrobin, famoxadone, benalaxyl‐M, iprovalicarb and benalaxyl, respectively) in their chemical formulation. RESULTS: Two commercial formulations, Cabrio Top and Fobeci, gave the highest efficacy to control this fungal disease. Once treated white grapes were harvested, the fate of these fungicides from vine to wine was studied. The white winemaking process allowed the dissipation of fungicide residues in high percentages (～95%), except for iprovalicarb (45%). Concentrations in final filtered white wines were close to or lower than 0.01 mg L^?1 for all detected fungicides except iprovalicarb and fludioxonil. The following dissipation rate was found: famoxadone > cyprodinil > pyraclostrobin > benalaxyl > folpet > fludioxonil > benalaxyl‐M > penconazole > iprovalicarb. CONCLUSION: From the data obtained in the vinification process, estimated maximum residue levels for white wines were proposed for future EU legislation to control the presence of pesticides in white wines. Thereby one helps to assure also the wine quality and protection of consumer health. Copyright © 2009 Society of Chemical Industry