Sensing Cu2+ by controlling the aggregation properties of the fluorescent dye rhodamine 6G with the aid of polyelectrolytes bearing different linear aromatic density

The importance of the linear aromatic density of polyelectrolytes on the ability to bind and influence the state of aggregation of dyes such as rhodamine 6G is highlighted. The corresponding complexes present different interaction patterns with metal ions such as Cu²⁺, undergoing different spectroscopic changes. The chemical bases of these changes are discussed. The different polyelectrolytes studied, poly(sodium 4-styrenesulfonate), poly(sodium 4-styrenesulfonate-co-sodium maleate) at two different comonomer compositions (3:1 and 1:1), and poly(sodium acrylate-co-sodium maleate), bear different linear aromatic density and induce different R6G binding patterns, as seen by diafiltration and UV–vis spectroscopy of absorbance and fluorescence. As the linear aromatic density increases, smaller dye aggregates are induced in the systems. Thus, in the presence of a large excess of the polyelectrolyte showing the highest linear aromatic density, the dyes disperse on the polymer domain and no aggregation is detected. The interaction is less sensitive to the cleaving effect produced by the addition of NaCl 0.1M for the complexes that include the polyelectrolytes with the highest linear aromatic density. In the presence of Cu²⁺, the complexes formed with the polyelectrolytes showing the lowest linear aromatic density tend to cleave, producing the release of the dye from the polymer domain. On the contrary, the complexes formed with the polyelectrolytes showing the highest linear aromatic density effectively retain the dye in the presence of the divalent metal ion. Based on fluorescence changes by the addition of different amounts of Cu²⁺ to the solution, the potential of the polyelectrolyte/R6G complexes in applications as sensing materials is discussed.     

Multi-objective optimization minimizing cost and life cycle emissions of stand-alone PV–wind–diesel systems with batteries storage

This paper describes an application of the Strength Pareto Evolutionary Algorithm to the multi-objective optimization of a stand-alone PV–wind–diesel system with batteries storage. The objectives to be minimized are the levelized cost of energy (LCOE) and the equivalent carbon dioxide (CO₂) life cycle emissions (LCE).     

Contact length estimation in grinding using thermocouple measurement and numerical simulation

Important research efforts are being devoted to the analysis and optimization of grinding operations. Due to the large number of variables involved in the process, a deeper understanding of the nature of contact mechanics between wheel and workpiece is required. The possibility of a sound estimation of the actual contact length is a critical issue, since this is related to thermal phenomena, chip geometry and pressure distribution. In this work, a new methodology for the estimation of the actual contact length in grinding is presented. The proposal uses the theoretical definition using numerical simulation of an indicator that univocally determines accurately the contact time on the plot temperature vs. time as measured by contact thermocouples. Experimental results show an excellent fit with previous estimations of contact length found in literature. The method can be extended to the characterization of wheel topography.     

On the origin of the evolutionary computation species influences of Darwin’s theories on computer science

This paper presents a small sample of evidences of the direct and clear influence of the Darwin??s Theory of Evolution on the Computer Science field, putting the core seed of the well-known Evolutionary Computation and making Computer Science overcome some previous algorithmic limitations. The paper also shows how the more faithful to the Evolution Theory the algorithms, the better their performance and robustness, thus uncovering the crucial importance of the ideas collected in ??On the Origin of Species?? for the development of Computation and, indirectly through this, for the development of a great diversity of knowledge areas.     

Local impact of renewables on employment: Assessment methodology and case study

This paper presents an integrated method that assesses the socio-economic impact of establishing renewable energy on a regional scale, in particular on the creation of jobs. The method proposed is based on the collection, critical analysis and presentation of the results obtained using primary information sources considering the jobs created as the most direct measure of the socio-economic potential of renewable energy sources. Its design includes contributions extracted from a prior analysis of the existing assessment methods, to lessen the uncertainty of the job ratios often used in these types of analysis. The integrated method implemented has been applied to the autonomous community of Aragon (Spain) as a pilot case, through which the method has been tested and the indicators selected to analyse the socio-economic impact of renewable energy sources on the jobs created, the quality of the jobs and other factors related to the socio-economic development of a territory: technological development, per capita income, territorial development and human capital.     

Algorithms for coupled problems that preserve symmetries and the laws of thermodynamics: Part I: Monolithic integrators and their application to finite strain thermoelasticity

We propose discretizations for a general class of nonlinear, coupled, thermomechanical problems of evolution. The most salient feature of the new methods is that they rigorously preserve the two laws of thermodynamics as well as the symmetries of the systems they model. To formulate such methods we exploit the geometric structure afforded by the GENERIC formalism of non-equilibrium thermodynamics and we follow a systematic methodology that results in discrete evolution equations which mimic the GENERIC structure. As an illustration, a complete discretization of finite strain thermoelasticity is presented, using finite elements in space and a monolithic integrator in time. Simulations are provided which demonstrate the conservation features of the algorithm as well as its remarkable robustness.     

Environmental analysis of the logistics of agricultural products from roof top greenhouses in Mediterranean urban areas

BACKGROUND: As urban populations increase so does the amount of food transported to cities worldwide, and innovative agro‐urban systems are being developed to integrate agricultural production into buildings; for example, by using roof top greenhouses (RTGs). This paper aims to quantify and compare, through a life cycle assessment, the environmental impact of the current linear supply system with a RTG system by using a case study for the production of tomatoes. RESULTS: The main results indicate that a change from the current linear system to the RTG system could result in a reduction, per kilogram of tomatoes (the functional unit), in the range of 44.4–75.5% for the different impact categories analysed, and savings of up to 73.5% in energy requirements. These savings are associated with re‐utilisation of packaging systems (55.4–85.2%), minimisation of transport requirements (7.6–15.6%) and reduction of the loss of product during transportation and retail stages (7.3–37%). CONCLUSIONS: The RTG may become a strategic factor in the design of low‐carbon cities in Mediterranean areas. Short‐term implementation in the city of Barcelona could result in savings of 66.1 tonnes of CO₂ eq. ha^?1 when considering the global warming potential, and of 71.03 t ha^?1 when considering that the transformation from woodland to agricultural land is avoided. Copyright © 2012 Society of Chemical Industry     

Valorization of grape pomace and orange peels: Improved production of hydrolytic enzymes for the clarification of orange juice

The production in solid state fermentation (SSF) of several hydrolytic enzymes by Aspergillus awamori on a mixture of grape pomace and orange peels has been studied in two configurations of bioreactor: packed bed and tray-type. When the effect of aeration in both reactors was compared, using the trays-type with an air flow rate of 3 mL/gds·min, average activities of 42.64 and 2.16 IU/gds were measured for xylanase and CMCase, respectively; however in the case of the column reactor the aeration must be doubled to obtain similar activity values. These differences were more significant in the case of exo-PG. The extracts obtained in this reactor were applied to orange juice and the cloudiness was markedly reduced, even improving the efficiency of a commercial enzyme preparation. Thus, while the turbidity of the fresh juice was 4625 NTU, treatment with the extracts reduced the value to 24.25 NTU. In a similar way the clarity increased to 95% after treatment with enzyme extracts. According to the results obtained, the proposed process for grape pomace and orange peels reutilization constitutes a viable alternative for many companies to revalorize their residues and to reduce their contaminant capacity.     

A Lallzyme MMX‐based rapid method for fission yeast protoplast preparation

Fungal cells including yeasts are surrounded by cell wall that counteracts turgor pressure and prevents cell lysis. Many yeast experiments, including genetic manipulation of sterile strains, morphogenesis studies, nucleic acid isolation and many others, require mechanical breakage or enzymatic removal of the cell wall. Some of these experiments require the generation of live cells lacking cell walls, called protoplasts, that can be maintained in osmostabilized medium. Enzymatic digestion of cell wall proteoglycans is a commonly used method of protoplast preparation. Currently existing protocols for fission yeast cell wall digestion are time consuming and not very efficient. We developed a new rapid method for fission yeast protoplast preparation that relies on digesting cell walls with Lallzyme MMX commercial enzyme mix, which produces protoplasts from all cells in less than 10 min. We demonstrate that these protoplasts can be utilized in three commonly used fission yeast protocols. Thus, we provide the fission yeast community with a robust and efficient plasmid extraction method, a new protocol for diploid generation and an assay for protoplast recovery that should be useful for studies of morphogenesis. Our method is potentially applicable to other yeasts and fungi. Copyright © 2013 John Wiley & Sons, Ltd.