The sustainability of European agricultural firms

There has been an undeniable and remarkable performance of the global food system over the last fifty years. During this period, total food supply has increased almost threefold, whereas population has only increase in a twofold ratio, along with very significant shifts in diet related to the economic development. European agricultural activity plays an important role in European and world food security through the agricultural production, supply and international trade. The main aim of this paper was analyses the agricultural sustainability of the twenty-eight Member States of the European Union in terms of economics, environmental, social and political activity. Information and data comes from FADN database from the European Commission related to the year 2013, because is the last information available. The methodology includes the min-max approach based on the four components of sustainability, namely, economic, social, environmental and politics. We include the new component of politics in the sustainability because European agricultural are high subsidised and these subsidies have impacts on European agricultural sustainability. All the referred components of sustainability were based on various indicators in each component based on the literature. The minmax approach was employed to normalise the selected indicators expressed in variety dimensions for their need to be put on a common basis. Multivariate methods, namely Component Principal Analysis was used to estimate weights for the selected indicators to construct sub-indices and then the subindices were aggregated into the farm relative sustainability index. After, cluster analysis was used to form homogeneous groups of European countries according the agricultural sustainability indices. The results confirm three groups of European countries, namely, the North and Central countries; the New Member States and the Mediterranean counties. The results confirm that European agriculture firms and respective countries had a medium sustainability. The results also confirm that Northern European countries and the New Member States (of Eastern Europe) presents the highest levels of economic and political sub-indices of sustainability, confirming the high level of support for EU agricultural policies. However, are the Mediterranean countries (Southern Europe) that presents the highest environmental sustainability sub-indices. The main conclusion highlines confirms the importance of the sustainability as a tool to better adjust agricultural policies among the European Member States and around the word in other sectorial firms, for better adjust sectorial policies.N/

New Energy Sources: The Enzymatic Biofuel Cell

The continuous search for alternative energy sources, imposed by economic and environmental concerns, has motivated investigations into clean and efficient alternatives for energy production. Studies have shown that fuel cells are a potentially efficient strategy for energy conversion. Biofuel cells constitute a subclass of fuel cells with promising application in low-power devices (generally in the order of micro to milli watts). Instead of metallic catalysts, biological power sources employ biological molecules such as enzymes, organelles, or microorganisms to convert chemical energy into electricity. Biofuel cells offer several advantages over traditional batteries, including the use of renewable and non-toxic components, reaction selectivity, fuel flexibility, and ability to operate at lower temperatures and near neutral pH. Indeed, recent papers have demonstrated the promising characteristics of these devices; however, some challenges remains to be faced despite the several advances in this area. This review aims to provide the readers of the Journal of the Brazilian Chemical Society with an overview of enzymatic biofuel cells, their development since its first description in 1964, and the most recent outcomes. The latest papers in this field (including implantable technology) and an outlook for future research in this area are also presented

Espectroscopia de impedância eletroquímica aplicada ao estudo das reações heterogêneas em ânodos dimensionalmente estáveis Electrochemical impedance spectroscopy applied in the study of heterogeneous reactions at dimensionally stable anodes

<abstract language="eng">This paper discusses different aspects related to the application of electrochemical impedance spectroscopy (EIS) in the study of heterogeneous electrochemical reactions occurring on Dimensionally Stable anodes (DSA®). The most relevant aspects of the semiconductor/electrolyte interface, the application of the EIS classical equivalent circuit approach and the ac porous model in DSA are presented. The paper shows that DSA type electrodes can be consistently investigated by using the ac porous model and an analysis is presented showing the advantage of applying this kind of approach to study heterogeneous reactions on DSA electrodes. Furthermore, some preliminary results on Ti/Ru0,3Ti(0,7-x)Sn x O2 based electrodes are presented to exemplify the use of the ac porous model analysis

Ethanol Biofuel Cells: Hybrid Catalytic Cascades as a Tool for Biosensor Devices

Biofuel cells use chemical reactions and biological catalysts (enzymes or microorganisms) to produce electrical energy, providing clean and renewable energy. Enzymatic biofuel cells (EBFCs) have promising characteristics and potential applications as an alternative energy source for low-power electronic devices. Over the last decade, researchers have focused on enhancing the electrocatalytic activity of biosystems and on increasing energy generation and electronic conductivity. Self-powered biosensors can use EBFCs while eliminating the need for an external power source. This review details improvements in EBFC and catalyst arrangements that will help to achieve complete substrate oxidation and to increase the number of collected electrons. It also describes how analytical techniques can be employed to follow the intermediates between the enzymes within the enzymatic cascade. We aim to demonstrate how a high-performance self-powered sensor design based on EBFCs developed for ethanol detection can be adapted and implemented in power devices for biosensing applications

Ethanol Biofuel Cells: Hybrid Catalytic Cascades as a Tool for Biosensor Devices

Biofuel cells use chemical reactions and biological catalysts (enzymes or microorganisms) to produce electrical energy, providing clean and renewable energy. Enzymatic biofuel cells (EBFCs) have promising characteristics and potential applications as an alternative energy source for low-power electronic devices. Over the last decade, researchers have focused on enhancing the electrocatalytic activity of biosystems and on increasing energy generation and electronic conductivity. Self-powered biosensors can use EBFCs while eliminating the need for an external power source. This review details improvements in EBFC and catalyst arrangements that will help to achieve complete substrate oxidation and to increase the number of collected electrons. It also describes how analytical techniques can be employed to follow the intermediates between the enzymes within the enzymatic cascade. We aim to demonstrate how a high-performance self-powered sensor design based on EBFCs developed for ethanol detection can be adapted and implemented in power devices for biosensing applications

Development of Plurimetallic Electrocatalysts Prepared by Decomposition of Polymeric Precursors for EtOH/O-2 Fuel Cell

This work aimed to develop plurimetallic electrocatalysts composed of Pt, Ru, Ni, and Sn supported on C by decomposition of polymeric precursors (DPP), at a constant metal: carbon ratio of 40:60 wt.%, for application in direct ethanol fuel cell (DEFC). The obtained nanoparticles were physico-chemically characterized by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). XRD results revealed a face-centered cubic crystalline Pt with evidence that Ni, Ru, and Sn atoms were incorporated into the Pt structure. Electrochemical characterization of the nanoparticles was accomplished by cyclic voltammetry (CV) and chronoamperometry (CA) in slightly acidic medium (0.05 mol L-1 H2SO4), in the absence and presence of ethanol. Addition of Sn to PtRuNi/C catalysts significantly shifted the ethanol and CO onset potentials toward lower values, thus increasing the catalytic activity, especially for the quaternary composition Pt64Sn15Ru13Ni8/C. Electrolysis of ethanol solutions at 0.4 V vs. RHE allowed determination of acetaldehyde and acetic acid as the main reaction products. The presence of Ru in alloys promoted formation of acetic acid as the main product of ethanol oxidation. The Pt64Sn15Ru13Ni8/C catalyst displayed the best performance for DEFC.CAPESCAPESFAPESPFAPESPCNPqCNP