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Currently, in many data landscapes, the information is distributed across various sources and presented in diverse formats. This fragmentation can pose a significant challenge to the efficient application of analytical methods. In this sense, distributed data mining is mainly based on clustering or classification techniques, which are easier to implement in distributed environments. However, the solution to some problems is based on the usage of mathematical equations or stochastic models, which are more difficult to implement in distributed environments. Usually, these types of problems need to centralize the required information, and then a modelling technique is applied. In some environments, this centralization may cause an overloading of the communication channels due to massive data transmission and may also cause privacy issues when sending sensitive data. To mitigate this problem, this paper describes a general-purpose distributed analytic platform based on edge computing for distributed networks. Through the distributed analytical engine (DAE), the calculation process of the expressions (that requires data from diverse sources) is decomposed and distributed between the existing nodes, and this allows sending partial results without exchanging the original information. In this way, the master node ultimately obtains the result of the expressions. The proposed solution is examined using three different computational intelligence algorithms, i.e., genetic algorithm, genetic algorithm with evolution control, and particle swarm optimization, to decompose the expression to be calculated and to distribute the calculation tasks between the existing nodes. This engine has been successfully applied in a case study focused on the calculation of key performance indicators of a smart grid, achieving a reduction in the number of communication messages by more than 91% compared to the traditional approach.

The proposal of this paper is to introduce a low-level blockchain marketplace, which is a blockchain where participants could share its power generation and demand. To achieve this implementation in a secure way for each actor in the network, we proposed to deploy it over efficient and generic low-performance devices. Thus, they are installed as IoT devices, registering measurements each fifteen minutes, and also acting as blockchain nodes for the marketplace. Nevertheless, it is necessary that blockchain is lightweight, so it is implemented as a specific consensus protocol that allows each node to have enough time and computer requirements to act both as an IoT device and a blockchain node. This marketplace will be ruled by Smart Contracts deployed inside the blockchain. With them, it is possible to make registers for power generation and demand. This low-level marketplace could be connected to other services to execute matching algorithms from the data stored in the blockchain. Finally, a real test-bed implementation of the marketplace was tested, to confirm that it is technically feasible.

Nowadays, the presence of renewable generation systems and mobile loads (i.e., electric vehicle) spread throughout the distribution network is increasing. The problem is that this type of system introduces an added difficulty since they present a strong dependence on the meteorology and the mobility needs of the users. This problem forces the distribution system operators to seek tools that make it possible to balance the relationship between consumption and generation. In this sense, automated demand response systems are an appropriate solution that allow the operator to request specific reductions in customers’ consumption, offering a discount to the customer and avoiding network congestion. This paper analyzes the implementation and architecture of a demand response solution based on OpenADR standard and its possible integration with a building management system through a use case. As will be analyzed, a key part of the architecture is the measurement system based on smart meters acting as sensors. This is the base of the auditing system which makes it possible to verify compliance with the consumption reduction agreements. Additionally, this study is completed with a parallel auditing system which makes it possible to verify compliance with the consumption reduction agreements. All of the proposed demand response cycle is implemented as a proof of concept in a classroom in the Escuela Politécnica Superior at the University of Seville, which makes it possible to identify the advantages of this architecture in the ambit of connection between distribution network and buildings.

Nowadays, Distribution System Operators are increasing the digitalization of their smart grids, making it possible to measure and manage their state at any time. However, with the massive eruption of change-distributed generation (e.g., renewable resources, electric vehicles), the grid operation have become more complex, requiring specific technologies to balance it. In this sense, the demand-side management is one of its techniques, the demand response is a promising approach for providing Flexibility Services (FSs) and complying with the regulatory directives of the energy market. As a solution, this paper proposes the use of the OpenADR (Open Automated Demand Response) standard protocol in combination with a Decentralized Permissioned Market Place (DPMP) based on Blockchain. On one hand, OpenADR hierarchical architecture based on distributed nodes provides communication between stakeholders, adding monitoring and management services. Further, this architecture is compatible with an aggregator schema that guarantees the compliance with the strictest regulatory framework (i.e., European market). On the other hand, DPMP is included at different levels of this architecture, providing a global solution to Flexibility Service Providers (FSP) that can be adapted depending on the regulation of a specific country. As a proof of concept, this paper shows the result of a real experimental case, which implements a Capacity Bidding Program where the OpenADR protocol is used as a communication method to control and monitor energy consumption. In parallel, the proposed DPMP based on Blockchain makes it possible to manage the incentives of FSs, enabling the integration of local and global markets.

In this paper, an intelligent data analysis method for modeling and optimizing energy efficiency in smart buildings through Data Analytics (DA) is proposed. The objective of this proposal is to provide a Decision Support System (DSS) able to support experts in quantifying and optimizing energy efficiency in smart buildings, as well as reveal insights that support the detection of anomalous behaviors in early stages. Firstly, historical data and Energy Efficiency Indicators (EEIs) of the building are analyzed to extract the knowledge from behavioral patterns of historical data of the building. Then, using this knowledge, a classification method to compare days with different features, seasons and other characteristics is proposed. The resulting clusters are further analyzed, inferring key features to predict and quantify energy efficiency on days with similar features but with potentially different behaviors. Finally, the results reveal some insights able to highlight inefficiencies and correlate anomalous behaviors with EE in the smart building. The approach proposed in this work was tested on the BlueNet building and also integrated with Eugene, a commercial EE tool for optimizing energy consumption in smart buildings.

Foodomics involves the study of food and nutrition domains through the application and integration of advanced omics technologies, such as transcriptomics, proteomics and metabolomics. This integration, together with biostatistics, chemometrics and bioinformatics tools allows the evaluation of complex biological systems, like those involved in the underlying mechanisms of bioactive food compounds that help to interpret the association between dietary exposure and health. In this review, we present a critical discussion of the recent developments in Foodomics approaches (including metabolomics, proteomics and transcriptomics) to understand the bioactivity of food and food ingredients on health as well as for the discovery of novel biomarkers related to such activity., This work was supported by projects AGL2014-53609-P and SAF2013-43475.

The first-order transition from low to superprotonic conducting phase (at 119

One of the fundamental tasks of electric distribution utilities is guaranteeing a continuous supply of electricity to their customers. The primary distribution network is a critical part of these facilities because a fault in it could affect thousands of customers. However, the complexity of this network has been increased with the irruption of distributed generation, typical in a Smart Grid and which has significantly complicated some of the analyses, making it impossible to apply traditional techniques. This problem is intensified in underground lines where access is limited. As a possible solution, this paper proposes to make a deployment of a distributed sensor network along the power lines. This network proposes taking advantage of its distributed character to support new approaches of these analyses. In this sense, this paper describes the aquiculture of the proposed network (adapted to the power grid) based on nodes that use power line communication and energy harvesting techniques. In this sense, it also describes the implementation of a real prototype that has been used in some experiments to validate this technological adaptation. Additionally, beyond a simple use for monitoring, this paper also proposes the use of this approach to solve two typical distribution system operator problems, such as: fault location and failure forecasting in power cables.

Field-effect experiments on cuprates using ionic liquids have enabled the exploration of their rich phase diagrams [Leng X, et al. (2011) Phys Rev Lett 107(2):027001]. Conventional understanding of the electrostatic doping is in terms of modifications of the charge density to screen the electric field generated at the double layer. However, it has been recently reported that the suppression of the metal to insulator transition induced in VO by ionic liquid gating is due to oxygen vacancy formation rather than to electrostatic doping [Jeong J, et al. (2013) Science 339(6126):1402-1405]. These results underscore the debate on the true nature, electrostatic vs. electrochemical, of the doping of cuprates with ionic liquids. Here, we address the doping mechanism of the high-temperature superconductor YBaCuO (YBCO) by simultaneous ionic liquid gating and X-ray absorption experiments. Pronounced spectral changes are observed at the Cu K-edge concomitant with the superconductor-to-insulator transition, evidencing modification of the Cu coordination resulting from the deoxygenation of the CuO chains, as confirmed by first-principles density functional theory (DFT) simulations. Beyond providing evidence of the importance of chemical doping in electric double-layer (EDL) gating experiments with superconducting cuprates, our work shows that interfacing correlated oxides with ionic liquids enables a delicate control of oxygen content, paving the way to novel electrochemical concepts in future oxide electronics., A.M.G. was supported partially by US National Science Foundation Award DMR-1420013 through the Minnesota Materials Research Science and Engineering Center and by US National Science Foundation Award DMR-1209578. J.G.-B. acknowledges support from the Ministerio de Economía, Industria y Competitividad (MINECO) through the Ramon y Cajal Program and through MINECO Award PCIN-2013-061. Calculations were performed using computer resources from Genci Grand Équipement National de Calcul Intensif under Centre Informatique National de l’Enseignement Suprieur Grants c2015097211 and c2016097211. Work at Universidad Complutense de Madrid was supported by the Spanish MINECO through Grants MAT2014-52405-C02-01 and Consolider Ingenio 2010-CSD2009-00013 (Imagine) and by Comunidad Autonoma de Madrid (CAM) through Grant CAM S2013/MIT-2740. The SpLine beamline is supported financially by the Spanish MINECO and Consejo Superior de Investigaciones Cientificas under Grant PIE 2010 6 OE 013. P.S. acknowledges the support from Fundação de Amparo à Pesquisa do Estado de São Paulo Projects 2012/18397-2 and 2013/12537-9.

A systematic study of Li 1 + x M x Ti 2 − x (PO 4 ) 3 with M = Al, Cr and Fe and 0 ≤ x ≤ 1 has been carried out by X-ray and neutron powder diffraction and by impedance spectroscopy. The analysis of the diffraction data allowed us to describe the disposition of the lithium atoms within the structure. They were found to occupy two different positions, the well-known M1 and a new position called M2′. The addition of trivalent metals into the LiTi 2 (PO 4 ) 3 compound, even in small amount, gives rise to the liberation of the M1 sites and simultaneous occupation of the M2′ sites. This situation becomes more pronounced as the substituent content increases, meaning a higher delocalization of lithium atoms within the structure. Moreover, rising temperature also provokes the movement of lithium from M1 to M2′. The impedance spectroscopy measurements allowed us to relate the electrical properties to the observations of the crystal structure. Both dc bulk and grain boundary ionic conductivity show a thermally activated behavior, and their values increase with substituent content until compositions of x = 0.2–0.3. The activation energy for bulk dc conductivity hardly changes with the substitution, and the main factor affecting the variation of the ionic conductivity is the pre-exponential factor. We find indeed a correlation between the pre-exponential factor and the degree of disorder of the lithium atoms in the structure as determined from neutron diffraction data. The highest conductivity was found in the sample Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 with a value of 6.2 × 10 − 3 S cm − 1 at room temperature and activation energy of 0.30 eV, which is comparable with those measured in the best ionic conductors reported to date.

The acquisition of data in protected natural environments is subordinated to actions that do not stress the life-forms present in that environment. This is why researchers face two conflicting interests: autonomous and robust systems that minimize the physical interaction with sensors once installed, and complex enough ones to capture and process higher volumes of data. On the basis of this situation, this paper analyses the current state-of-the-art of wireless multimedia sensor networks, identifying the limitations and needs of these solutions. In this sense, in order to improve the trade-off between autonomous and computational capabilities, this paper proposes a heterogeneous multiprocessor sensor platform, consisting of an ultra-low power microcontroller and a high-performance processor, which transfers control between processors as needed. This architecture allows the shutdown of idle systems and fail-safe remote reprogramming. The sensor equipment can be adapted to the needs of the project. The deployed equipment incorporates, in addition to environmental meteorological variables, a microphone input and two cameras (visible and thermal) to capture multimedia data. In addition to the hardware description, the paper provides a brief description of how long-range (LoRa) can be used for sending large messages (such as an image or a new firmware), an economic analysis of the platform, and a study on energy consumption of the platform according to different use cases.

Optical and electrical properties of samples with Li 1 + x Cr x Ti 2 − x (PO 4 ) 3 composition ( x = 0, 0.05 and 0.1) prepared by a low temperature sol-gel method have been investigated. XRD and Raman spectroscopy measurements respectively reveal the rhombohedral-Nasicon structure of the grown samples and a disorder of Li + ions with increasing chromium content. Electrical properties were studied by impedance spectroscopy and both dc and grain boundary ionic conductivity increase with Cr content. A high ionic conductivity value of 1.4·10 − 4 S cm − 1 at room temperature and an activation energy of 0.31 eV have been obtained for x = 0.1, which are comparable to those measured in the best ionic conductors reported to date. Photoluminescence and cathodoluminescence spectra indicate that self-trapped excitons and oxygen defects related to the TiO 6 octahedra structural units are responsible for the observed luminescence in the visible spectral range, explaining the possible electronic origin of a residual conductivity measured in all the samples. Cr incorporation gives rise to infrared emission bands, attributed to different Cr 3 + and Ti 3 + intraionic transitions, that may be related to the better grain connectivity achieved by Cr doping.

This paper proposes a novel and autonomous weighing system for wild animals. It allows evaluating changes in the body weight of animals in their natural environment without causing stress. The proposed system comprises a smart scale designed to estimate individual body weights and their temporal evolution in a bird colony. The system is based on computational intelligence, and offers valuable large amount of data to evaluate the relationship between long-term changes in the behavior of individuals and global change. The real deployment of this system has been for monitoring a breeding colony of lesser kestrels (Falco naumanni) in southern Spain. The results show that it is possible to monitor individual weight changes during the breeding season and to compare the weight evolution in males and females.

Environmental audio monitoring is a huge area of interest for biologists all over the world. This is why some audio monitoring system have been proposed in the literature, which can be classified into two different approaches: acquirement and compression of all audio patterns in order to send them as raw data to a main server; or specific recognition systems based on audio patterns. The first approach presents the drawback of a high amount of information to be stored in a main server. Moreover, this information requires a considerable amount of effort to be analyzed. The second approach has the drawback of its lack of scalability when new patterns need to be detected. To overcome these limitations, this paper proposes an environmental Wireless Acoustic Sensor Network architecture focused on use of generic descriptors based on an MPEG-7 standard. These descriptors demonstrate it to be suitable to be used in the recognition of different patterns, allowing a high scalability. The proposed parameters have been tested to recognize different behaviors of two anuran species that live in Spanish natural parks; the Epidalea calamita and the Alytes obstetricans toads, demonstrating to have a high classification performance.

El pdf del artículo es la versión pre-print., In this work, a novel screening methodology based on the combined use of multiplex polymerase chain reaction (PCR) and capillary gel electrophoresis with laser induced fluorescence (CGE-LIF) is developed for the fast and sensitive detection of genetically modified yeasts in wine. As model, a recombinant EKD-13 Saccaromyces cerevisiae strain was selected and different wines were prepared using either recombinant or conventional yeasts. Special emphasis is put on the yeast DNA extraction step, exploring different commercial and non-commercial methods, in order to overcome the important difficulty of obtaining amplifiable DNA from wine samples. To unequivocally detect the transgenic yeast, two specific segments of the transgenic construction were amplified. In addition, a third primer pair was used as amplification control to confirm the quality of the yeast DNA obtained from the extraction step. CGE-LIF provides high sensitivity, good analysis speed and impressive resolution of DNA fragments, making this technique very convenient to optimize multiplex PCR parameters and to analyze the amplified DNA fragments. Thus, the CGE-LIF method provided %RSD values for DNA migration times lower than 0.82% (n= 10) with the same capillary and lower than 1.92% (n= 15) with three different capillaries, allowing the adequate size determination of the PCR products with an error lower than 4% compared to the theoretically expected. The whole method developed in this work requires less than one working day and grants the sensitive detection of transgenic yeasts in wine samples. © 2011 Elsevier B.V., This work was supported by a CSIC-Beckman Coulter contract, AGL2008-05108-C03-01 (Ministerio de Ciencia e Innovacion) and the CSIC project 200970I083.

The development of genetically modified crops has had a great impact on the agriculture and food industries. However, the development of any genetically modified organism (GMO) requires the application of analytical procedures to confirm the equivalence of the GMO compared to its isogenic non-transgenic counterpart. Moreover, the use of GMOs in foods and agriculture faces numerous criticisms from consumers and ecological organizations that have led some countries to regulate their production, growth, and commercialization. These regulations have brought about the need of new and more powerful analytical methods to face the complexity of this topic. In this regard, MS-based technologies are increasingly used for GMOs analysis to provide very useful information on GMO composition (e.g., metabolites, proteins). This review focuses on the MS-based analytical methodologies used to characterize genetically modified crops (also called transgenic crops). First, an overview on genetically modified crops development is provided, together with the main difficulties of their analysis. Next, the different MS-based analytical approaches applied to characterize GM crops are critically discussed, and include "-omics" approaches and target-based approaches. These methodologies allow the study of intended and unintended effects that result from the genetic transformation. This information is considered to be essential to corroborate (or not) the equivalence of the GM crop with its isogenic non-transgenic counterpart.

In this work, the potential of combining capillary electrophoresis-time-of-flight-mass spectrometry (CE-TOF-MS) and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) for metabolomics of genetically modified organisms (GMOs) is demonstrated. Thus, six different varieties of maize, three of them transgenic (PR33P66 Bt, Tietar Bt and Aristis Bt) and their corresponding isogenic lines (PR33P66, Tietar and Aristis) grown under the same field conditions, were analyzed. Based on the ultrahigh resolution and remarkable mass accuracy provided by the 12-T FT-ICR-MS it was possible to directly analyze a good number of metabolites whose identity could be proposed based on their specific isotopic pattern. For identification of metabolite isomers, CE-TOF-MS was also used combining the information on nominal mass with electrophoretic mobility corroborating in that way the identity of several new biomarkers. Furthermore, PLE extractions were evaluated in order to establish selective extraction as an additional criterion to obtain useful information in maize metabolomics. Differences in the metabolite levels were found between the three transgenic maize varieties compared with their wild isogenic lines in some specific metabolic pathways. To our knowledge, this is the first time that an approach as the one presented in this work (pressurized liquid extraction+FT-ICR-MS+CE-TOF-MS) is shown for a metabolomic study.

In this work, three modified CDs (mCDs), namely 6-deoxy-6-[1-(2-amino)ethylamino]-beta-CD, 6-deoxy-6-[N-(2-methylamino)pyridine)]-beta-CD and 3-monodeoxy-3-monoamino-beta-CD, are investigated as chiral selectors for CE with LIF (CE-LIF) and CE-TOF-MS. The potential of these three mCDs as chiral selectors in CE was also compared with the unmodified beta-CD and gamma-CD. A group of ten different D- and L-amino acids derivatized with FITC was selected as case-study for CE-LIF and CE-MS comparison. The analyte group includes negatively (D/L-Glu and D/L-Asp), neutral (D/L-Ala and D/L-Asn) and positively (D/L-Arg) charged amino acids. Chiral separation conditions compatible with CE-TOF-MS could be achieved based on the figures of merit obtained by CE-LIF using the different CDs. Interestingly, LOD values obtained by chiral CE-TOF-MS were in the nM range comparable or only slightly worse to those obtained by CE-LIF. Moreover, the time of analysis using mCDs was reduced more than 30% compared with the non-chiral conditions (19.2 versus 28.4 min, respectively), with resolution and efficiency values as high as 5.15 and 843 000 plates/m, respectively. The usefulness of this chiral CE-TOF-MS method was corroborated through the detection of the main D- and L-amino acids found in different real samples including transgenic versus wild soy and vinegar.

We investigate the effect of cation size in the dc activation energy needed for oxygen ion conductivity, Edc, in highly disordered pyrochlore-type ionic conductors A2B2O7. Twenty compositions of general formula Ln2Zr2-yTiyO7 (Ln = Y, Dy and Gd) and Gd2-yLayZr2O7, were prepared by mechanical milling and their electrical properties measured by using impedance spectroscopy at different temperatures. We also evaluate, by using Ngai’s Coupling Model, the effect of cation radii RA and RB, on the microscopic potential-energy barrier, Ea, that oxygen ions encounter when jumping into neighboring vacant sites. We find that for a fixed B-site cation radius RB, both activation energies decrease with increasing A-site cation size, RA, as a consequence of the increment in the unit cell volume. In contrast, and for a given RA size, the dc activation energy Edc of the Ln2Zr2-yTiyO7 series increases when the average RB size increases. The latter behavior is explained in terms of the enhanced interactions among mobile oxygen ions as the structural disorder increases when RB approaches RA.

As SOFC technology relies at present on La-based perovskites as cathode materials, we have analyzed the effect La-incorporation might have in the ionic conductivity of P-Gd 2 Zr 2 O 7 , a pyrochlore-type fast oxygen ion conductor. Single phase powder samples with different La/Gd ratio, were prepared in the pyrochlore-type Gd 2 − y La y Zr 2 O 7 solid solution (0 ≤ y ≤ 1) by mechanically milling stoichiometric mixtures of the corresponding oxides. Electrical conductivity measurements were performed for different compositions by using pressed pellets sintered at 1500 °C, as a function of frequency and temperature. Despite of increasing structural ordering (decreasing number of mobile charge carriers), it was found that oxide–ion conduction at intermediate temperatures is almost La-content independent for y ≤ 0.8 because of decreasing dc activation energy (from 1.13 to 0.85 eV). We show that these results can be explained in terms of weaker ion–ion interactions in better ordered structures (i.e., rich La-content), highlighting the importance of structural ordering/disordering in determining the dynamics of mobile oxygen ions.

In this work, two different CE-MS instruments, namely, CE-ESI-IT-MS and CE-ESI-TOF-MS, applied to analyse intact proteins from complex samples are investigated. The aim of this work was to compare both instruments in terms of LOD, number of proteins detected, and precision and repeatability in the determination of the protein relative molecular mass. Results show that although CE-ESI-IT-MS provides cleaner MS spectra of intact proteins, CE-ESI-TOF-MS allows the identification of a higher number of proteins from complex matrices in an easier way. Performance in terms of peak area reproducibility, LOD and precision in the determination of the molecular mass were similar for both instruments. The usefulness of the optimised CE-ESI-IT-MS and CE-ESI-TOF-MS conditions was demonstrated by studying the zein-proteins composition of three natural maize lines and their corresponding transgenic lines, showing no significant differences.

We investigate ion dynamics under pressure in the ionic liquid 1-butyl-1-methylpyrrolidinium bis[oxalate]borate (BMP-BOB) by conductivity relaxation measurements in the temperature range 123-300 K and varying pressures from 0.1 MPa up to 0.5 GPa. We report on the influence of pressure on the relaxation times and on the spectral shape of the conductivity relaxation process. We also analyze the pressure dependence of the glass transition temperature and find that the dynamic response under pressure in this ionic liquid shows remarkable similarities to nonionic glass formers. The main relaxation process shows temperature-pressure superposition while a secondary relaxation process, very weakly depending on pressure, is observed. The spectral shape of the main relaxation broadens with increasing pressure or decreasing temperature, but is found to be the same when the relaxation time is the same, independently of the particular pressure and temperature values.

We report on the influence of structural disorder on the oxide-ion conductivity of Dy2(Ti1� yZry)2O7 (y = 0.55 and 0.90). A significant disorder is induced by mechanical milling synthesis of the samples, and, depending on the Zr/Ti, a partial and progressive structural ordering can be achieved by subsequent annealing at temperatures between 800 and 1500 C. Ionic conductivity is relatively high for both compositions (up to 10 � 4 S/cm at 900 K), and the activation energies for dc conductivity (in the range 1.02–1.32 eV) are found to be larger in samples with more structural disorder. This result is quantitatively explained, by using Ngai’s coupling model, in terms of the enhancement of interactions between mobile oxygen vacancies in a more disordered structure. 2007 Elsevier B.V. All rights reserved.

Lead(II) alkanoates, from hexanoate to dodecanoate, have been analyzed by means of XRD, optical microscopy, DSC, FTIR, and electric spectroscopy. Four different phases have been identified, corresponding to the three thermal transitions measured by DSC: two of them solid (crystal and “intermediate” phases), and another two fluid (neat phase and isotropic liquid). Powder crystal XRD data indicate that the samples present a bilayered structure. The analysis of the (00l) spacing dependence with temperature in the three ordered phases strongly points to the intermediate phase to be a rotator phase. Optical microscopy and FTIR versus temperature also confirm a structural change from the crystal to the intermediate phase and its solid-state nature. Electrical conductivity maps the thermal transitions of the samples and shows a high ionic conductivity in the intermediate phase, which does not depend much on the carbon chain length. The high conductivity values (3 orders of magnitude higher in comparison with th...

Li_(1+x)M_(x)Ti_(2−x)(PO_(4))_(3) powders with x = 0 and 0.3 and M = Al, Cr and Fe have been sintered by conventional sintering (CS) and Spark Plasma Sintering (SPS), and the electrical properties have been compared. The use of SPS allows preparing samples with higher density at lower temperature and shorter time than the CS, avoiding segregation of secondary phases and with reduced crystallite size. The introduction of aluminum, chromium and iron in the LiTi_(2)(PO_(4))_(3) (LTP) clearly enhances ionic conductivity even if the samples have similar densities. Despite the different level of density reached with CS and SPS, the activation energies of dc and grain boundary contributions are very similar and the differences in ionic conductivity are determined by pre-exponential factors. The samples produced by SPS showed a well-defined grain boundary meaning a more homogenous electrical contact.

Different compositions in a solid solution of general formula Dy2(Ti1−yZry)2O7, showing high oxygen ion conductivity, have been successfully prepared at room temperature via mechanochemical synthesis. Stoichiometric mixtures of the constituent oxides were dry milled together in a planetary ball mill by using zirconia vials and balls. Chemical changes in the powder mixtures as a function of composition and milling time were followed by X-ray diffraction and revealed that, in all cases and after milling for 19 h, the powder mixtures consisted of a single phase. Electrical properties were measured on sintered pellets as a function of frequency, temperature and zirconium content, revealing an increase in conductivity of more than one order of magnitude for y ⩾ 0.4 , which, as observed in the similar Y2(Ti1−yZry)2O7, has been related with the onset of disordering of the anion sublattice. Despite increasing structural disorder with increasing Zr content, conductivity remains almost constant for y > 0.6 , reaching a maximum value of ∼5×10−3 for Dy2Zr2O7 at 900 °C.

Several compositions within the Gd{sub 2}(Sn{sub 1-y}Zr{sub y}){sub 2}O{sub 7} solid solution with a pyrochlore-type of structure, have been prepared at room temperature in a planetary ball mill starting from stoichiometric mixtures of the constituent oxides, SnO{sub 2}, ZrO{sub 2} and Gd{sub 2}O{sub 3}. Phase evolution in the powder mixtures as a function of composition and milling time was followed by X-ray diffraction (XRD) finding out that after 18h, every mixture consist of a single phase. Mechanically activated chemical reaction takes place after an intial step of particle size refinement and polymorphic transformation of C-Gd{sub 2}O{sub 3}. We have performed Impedance Spectroscopy measurements to investigate oxygen ion dynamics in the series and conclude that Zr substitution for Sn hardly modifies the importance of ion-ion correlations in the oxygen diffusion process. We also estimate from conductivity measurements the value of the microscopic activation energy needed for independent ion hopping, which is found to be 0.56+/-0.06eV, independent of Zr content.

We analyze ion dynamics in the oxygen ion conductor Gd2Ti2−yZryO7 by impedance spectroscopy measurements. We find that electrical conductivity relaxation is well described by stretched exponentials of the form Φ(t) = exp(−(t/τ)1−n), with the fractional exponent n increasing systematically with Zr content. Increasing Zr content also leads to an increase in the activation energies for long-range ion diffusion from 0.7 to 1.0 eV. These results are explained in terms of the enhanced cooperativity in oxygen ion dynamics when increasing the concentration of mobile oxygen vacancies with Zr content.

We present electrical conductivity measurements of BIFEVOX Bi4V2-xFexO11-y (0≤x≤0.9; 0≤y≤1), in which V (IV) ions have been systematically substituted by Fe (III) ions. Conductivity shows a power law frequency dependence described by the form σ*(ω)=σdc[1+(jω/ωp)n], known as universal dynamic response. Conversely, the electric modulus shows asymmetric peaks, characterized by stretched exponentials relaxation functions in time domain of the form φ(t)=exp(-(t/τσ)β). β is determined by the degree of correlation in the ionic motion. It´s value, β=0.56±0.03, is almost independent of temperature and iron content. Increasing Fe content leads to an exponential decrease of the conductivity and to an increase of the activation energy of the conduction process from 0.20 to 0.97 eV. These results are discussed in terms of oxygen vacancy ordering upon Fe (III) substitution.Presentamos medidas de la conductividad eléctrica del sistema BIFEVOX Bi4V2-xFexO11-y (0≤x≤0.9; 0≤y≤1), en el que se realiza la sustitución de iones V (IV) por Fe (III) de forma sistemática. La conductividad muestra un comportamiento potencial con la frecuencia, descrito por σ*(ω)=σdc[1+(jω/ωp)n], y conocido como respuesta dieléctrica universal. Análogamente, el módulo eléctrico presenta picos asimétricos, cuya función de relajación en el dominio del tiempo puede describirse mediante exponenciales “estiradas” de la forma φ(t)=exp(-(t/τσ)β). β da cuenta del grado de correlación del transporte iónico, siendo su valor, β=0.56±0.03, casi independiente de la temperatura y del contenido en Fe. Con el aumento en el contenido de Fe, la conductividad disminuye exponencialmente y la energía de activación del proceso de conducción aumenta de 0.20 a 0.97 eV. Estos resultados se discuten en términos de la ordenación de vacantes oxígeno al dopar con Fe (III).

The effect of high-temperature treatments on the structure and lithium mobility of the Li3xLa2/3-xTiO3 (0.03 ≤ x ≤ 0.167) series has been studied by HTXRD, Raman, NMR, and impedance spectroscopies. Room temperature XRD patterns of slowly cooled samples display a c-doubled perovskite with orthorhombic or tetragonal symmetries, whereas those of quenched samples display a simple cubic perovskite. However, Raman spectra of analyzed samples are interpreted, in all the cases, with a tetragonal symmetry in which cation disorder increases with the lithium content and quenching treatments. The existence of small microtwinned domains, arranged along the three directions of the perovskite, favors detection of the cubic phase in XRD patterns. From 7Li NMR spectroscopy a two-dimensional Li motion was detected in ordered samples, which becomes progressively three-dimensional as cation disordering increases. The presence of microdomains decreases the dc-conductivity of quenched Li-poor samples.

The dependence of ionic transport properties on the structure and composition of perovskites Li0.5-xNaxLa0.5TiO3 (0 ≤ x ≤ 0.5) has been analyzed by means of ND, XRD, NMR, and impedance spectroscopy. Local lithium mobility is shown to decrease progressively by 2 orders of magnitude along the series; however, long-range dc conductivity decreases sharply at x = 0.2 more than 6 orders of magnitude. The decrease of dc conductivity from values typical of fast ionic conductors, 10-3 S/cm at room temperature, to values of insulators, 10-10 S/cm, is discussed in terms of a three-dimensional percolation model for lithium diffusion. As deduced from XRD and ND data, the number of vacant sites in conduction pathways is controlled by the amount of Na and La in the perovskite.

We report on the temperature and mass dependence of the nearly constant loss (NCL) in several ionically conducting materials, both crystalline (Li0.18 La0.61 TiO3 and (Y2O3)0.16 (ZrO2)0.84) and glassy (M2O·3B2O3, M=Li, Na, K and Rb). The magnitude A of the NCL is found to be larger for those materials showing higher dc conductivity values at room temperature, and shows weak temperature dependence of the form A∝exp(bT) in all cases. We have also found that A systematically decreases upon increasing the mass of the mobile alkali ion in the borate glasses. All these results point to the relaxation of ions in a very slowly decaying cage as the origin of the NCL.

Correlation effects in the ionic conductivity of BIFEVOX (Bi 4 V 2-x Fe x O 11-y , 0 ≤ x ≤ 0.9, 0 ≤ y ≤ 1) by impedance spectroscopy measurements have been investigated. The real part of the conductivity shows power-law frequency dependence at high frequencies, and electric modulus plots show asymmetric peaks, as a consequence of correlations in the oxygen ion diffusion. Relaxation functions in the time domain are well-described by stretched exponentials of the form o(t) = exp(-(t/τ σ ) β ), with an exponent β = 0.56 ± 0.03, which is nearly independent of temperature and Fe content. It is found that the room temperature dc conductivity decreases exponentially when Fe content is increased and the dc conductivity activation energy increases from 0.20 to 0.97 eV. Results are discussed in terms of oxygen vacancy ordering upon Fe substitution in V sites.

We present a study of the nearly constant loss regime in the oxide-ion conductor Gd2Zr2O7 by using Impedance Spectroscopy measurements. At enough low temperature, between 173 and 253 K, the dielectric loss is found to be almost temperature and frequency independent within the whole experimental frequency range (10 Hz – 1 MHz). However, a symmetric and very broad relaxation peak is clearly resolved in the loss spectra. This peak shows a thermally activated peak frequency with activation energy Eτ = 0.29 ± 0.02 eV, and its origin is discussed in terms of previously proposed models for the nearly constant loss. Fil: Diaz Guillen, M. R.. Universidad Complutense de Madrid; España. Instituto de Investigaciones Eléctricas; México Fil: Frechero, Marisa Alejandra. Universidad Complutense de Madrid; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Diaz Guillen, J. A.. Instituto Tecnológico de Saltillo; México Fil: Fuentes, A. F.. Cinvestav Unidad Saltillo; México Fil: Leon, C.. Universidad Complutense de Madrid; España

The solid solution La2/3−xLi3xTiO3 (0.03

Dielectric relaxation measurements were performed on propylene glycol (PG) and oligomers having different number of repeat units (N=2, 3, and 69). The primary α-relaxation had the Kohlrausch–Williams–Watts (KWW) form, with a stretch exponent (1−n) which decreased with increasing N. The temperature dependence of the α-relaxation time, as reflected in the fragility index, increased with N. A broad, rather symmetric secondary β-relaxation was observed at higher frequencies in the dielectric loss spectrum for all samples with N>1. This is the first observation of the β-relaxation peak in dipropylene glycol (N=2) and tripropylene glycol (N=3). The separation between the α- and β-relaxations increased with increasing N. This trend indicates that the separation is minimal in PG, which makes it difficult to resolve the β-relaxation from the more intense α-relaxation. This, together with the fact that the strength of the β-relaxation decreases with the molecular weight of PPG, as found by Johari and coworkers, exp...

In this paper, we present results of current–voltage and admittance spectroscopy measurements on n + p junctions made by Si implantation into Zn doped In .53 Ga .47 As. The I–V characteristics show that the main conduction mechanisms at forward bias is recombination in the space-charge zone, whereas a thermally-activated tunneling dominates the reverse characteristics at low bias and trap-assisted tunneling at medium and high bias. The use of Kramers–Kronig transforms on the admittance spectroscopy data allow us to detect a deep level at 0.36 eV, probably ascribed to thermally activated Zn acceptor dopants in p-In .53 Ga .47 As.

A highly sensitive, catalytic adsorptive stripping voltammetric procedure at the hanging mercury drop electrode for the simultaneous determination of ultratraces of platinum and rhodium in electrolyte solutions has been evaluated. Optimal conditions were found to be: first accumulation potential 0 V (vs. Ag/AgCl), second accumulation potential −0.8 V, first preconcentration time 90 s, second preconcentration time 120 s, scan rate 20 mV s−1. The response of the system was found to be linear in a range of platinum concentrations up to 6 ng l−1 and for rhodium up to 0.5 ng l−1. The detection limit was 21 pg l−1 for platinum and 5.6 pg l−1 for rhodium. The effect of various possible interferences from other metal ions was also studied. With the exception of zinc (whose influence was studied in more detail), no significant interferences were observed. The method was successfully applied to the determination of traces of Pt and Rh in real environmental samples (spruce shoots) after high pressure digestion.

Wireless Sensor Networks (WSNs) are a technology that is becoming very popular for many applications, and environmental monitoring is one of its most important application areas. This technology solves the lack of flexibility of wired sensor installations and, at the same time, reduces the deployment costs. To demonstrate the advantages of WSN technology, for the last five years we have been deploying some prototypes in the Doñana Biological Reserve, which is an important protected area in Southern Spain. These prototypes not only evaluate the technology, but also solve some of the monitoring problems that have been raised by biologists working in Doñana. This paper presents a review of the work that has been developed during these five years. Here, we demonstrate the enormous potential of using machine learning in wireless sensor networks for environmental and animal monitoring because this approach increases the amount of useful information and reduces the effort that is required by biologists in an environmental monitoring task.

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY)., The local order around Zr and Y atoms of nanocrystalline yttria-stabilized zirconia (YSZ) powders with different grain sizes has been investigated by x-ray absorption spectroscopies. The samples were prepared by means of mechanical alloying with or without subsequent sintering treatment and also by milling commercial YSZ. Our study is motivated by the interest in the electrical properties of grain boundaries and the controversy about the level of disorder in the intergrain regions in nanocrystalline YSZ. The x-ray absorption near edge structure (XANES) analysis indicates that the local order of all the sintered samples is independent of the grain size. This is confirmed by the analysis of the extended x-ray absorption fine structure, which points out also that, in contrast to that found in sintered samples, the local order around the cation in the samples milled without further sintering treatment extends only to the first coordination shell. Finally, the results of ab initio Zr K-edge XANES calculations lead us to conclude that the observed changes of the shape of the white line are not related to a phase transformation but reflects the short-range order present in the as-milled samples. © 2013 American Physical Society., This work was partially supported by Spanish and MAT2011-27573-C04-04 grants, by Junta de Comunidades de Castilla-La Mancha through Project No. PCI-08-0091 and by the Aragón DGA NETOSHIMA grant.

The use of Kramers–Kronig transforms is proposed for the treatment of admittance spectroscopy data of junctions when significant shunt conductance or series resistance is present. An algorithm has been implemented to calculate the transformations numerically and the validity of the method developed has been tested using simulated data. Two experimental systems, p‐n junctions into InP made by ion implantation, and atomic‐layer‐epitaxy‐grown CdS/CdTe heterojunctions, have been characterized using this procedure.

High-Tc superconducting YBa2Cu3O7 ceramic samples are lithiated by the reaction with n-butyllithium. For lithium nominal contents less than unity per formula the presence of '123' and '124' phases are deduced from X-ray diffraction and high-resolution electron microscopy experiments. NMR and impedance spectroscopy techniques have been conducted in a sample with a nominal Li content of 0.9 per formula. Spin-lattice relaxation times and electrical conductivity relaxation (ECR) are measured as a function of temperature. NMR and ECR data are interpreted in terms of a stretched exponential decay function in the time domain. Microscopic activation energies for lithium motion of 0.49 eV (NMR measurements) and of 0.41 eV (ECR) are deduced for short range motion. Activation energies for long range motion of 0.98 eV (NMR) and 1.03 eV (ECR) are also deduced.

An unusual conducting surface state can be produced in SrTiO3 substrates by irradiation with Argon ions from a plasma source, at low energy and high doses. The effects of irradiation are analyzed here by atomic force microscopy (AFM) and aberration corrected scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS). Depth sensitive studies demonstrate the existence of a heavily damaged surface layer and an oxygen vacancy rich layer immediately underneath, both induced during the irradiation process. We find a clear dependence of the Ti oxidation state with the depth, with a very intense Ti 3 þ component near the surface. Oxygen vacancies act as n-type doping by releasing electrons into the lattice and producing an insulator-to-metal transition, which explains the unusual metallic behavior of these samples. Published by Elsevier B.V.

En este trabajo se presentan resultados de medidas de espectroscopia de impedancias realizadas en un bicristal del conductor iónico zirconia estabilizada con itria (YSZ). Utilizando electrodos de tamaño micrométrico se ha podido medir el transporte iónico a través, perpendicularmente, de una única frontera de grano, caracterizando eléctricamente las propiedades de dicha frontera. De este modo se han obtenido los parámetros microscópicos que determinan la distribución de carga en la frontera y por lo tanto el transporte iónico a través de ella, como son la barrera de potencial en la frontera DF = 0.35±0.01 V a 275 ºC, y el espesor de la zona de carga espacial l* = 5±1 Å. Estos valores son significativamente diferentes a los obtenidos anteriormente en muestras cerámicas policristalinas del mismo material, y muestran mejor acuerdo con los valores que predice el modelo de Mott-Schottky para la distribución de carga y el transporte iónico a través de la frontera de grano. Here we show impedance spectroscopy measurements on a bicrystal of the ionically conducting yttria stabilized zirconia (YSZ). By using micrometer sized electrodes it is possible to measure ionic transport perpendicular to a single grain boundary, and characterize its electrical properties. We are thus able to obtain the microscopic parameters that determine the charge distribution at the grain boundary and the ionic transport through it, as the potential energy barrier DF = 0.35±0.01 V at 275 ºC, and the space charge layer thickness l* = 5±1 Å. These values are significantly different from those previously obtained in polycrystalline ceramic samples of the same material, and show much better agreement with the values predicted by the Mott-Schottky model for the charge distribution and ionic transport through the grain boundary Fil: Frechero, Marisa Alejandra. Universidad Complutense de Madrid; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Rocci, M.. Universidad Complutense de Madrid; España Fil: Schmidt, R.. Universidad Complutense de Madrid; España Fil: Diaz Guillen, M.. Universidad Complutense de Madrid; España Fil: Dura, O.. Universidad Complutense de Madrid; España Fil: Rivera Calzada, A.. Universidad Complutense de Madrid; España Fil: Santamaria, J.. Universidad Complutense de Madrid; España Fil: Leon,C.. Universidad Complutense de Madrid; España

Capillary zone electrophoresis (CZE) has been applied to separation and characterisation of enzymatic (tryptic) hydrolysates of water-soluble proteins from Bacillus thuringiensis (Bt)-transgenic (Aristis-Bt) and two native non-transgenic (Aristis and Coventry) maize varieties. Water-soluble proteins were extracted from the flour of these maize species and digested by bovine pancreatic trypsin immobilised on agarose gel in 100 mM ammonium hydrocarbonate buffer, pH 7.9. The yielded tryptic digests of proteins were analysed by CZE in four acidic background electrolytes (BGEs) (100 mM H 3PO 4, 50 mM Tris, pH 2.25; 500 mM acetic acid, pH 2.54; 200 mM formic acid, 200 mM acetic acid, pH 2.05; and 200 mM iminodiacetic acid, pH 2.26) using a lab-made CZE apparatus equipped with bare fused silica capillary and UV-absorption detector operating at 206 nm. Among the tested BGEs, the best resolution of the tryptic peptides of extracted proteins of the above three maize species was obtained in isoelectric BGE, 200 mM iminodiacetic acid, pH 2.26. Selected resolved tryptic peptides of proteins were characterised by effective electrophoretic mobilities and corrected (migration times normalised) peak areas. Some significant relative qualitative and quantitative differences in CZE-UV profiling of tryptic protein digests were found, which can be potentially used to differentiate transgenic Aristis Bt and non-transgenic Aristis varieties or two native non-transgenic varieties, Aristis and Coventry. © 2012 Elsevier Ltd. All rights reserved., The work was supported by the National Science Foundation of the Czech Republic, the Grant No. 203/08/1428, by the Research Project AV0Z40550506 of the Academy of Sciences of the Czech Republic, and by the project 2008CZ0019 of cooperation between ASCR and CSIC.

The ionic conductivity of some double rate-earth chromates MLn(CrO 4 ) 2 (M=Na, K, Rb; Ln=La, Eu, Lu) has been analyzed by means of admittance spectroscopy. Real and imaginary part of the permittivity show the frequency power dependence characteristic of many-body interactions between mobile ions. Ac conductivity parameters are correlated with structural details of the compounds studied.

In this paper we present the structural, magnetic and dielectric properties of ceramic nickel manganite NiMn2O4+δ produced by using nickel permanganate Ni(MnO4)2xH2O as a precursor. We have characterized the NiMn2O4+δ stoichiometry using quantitative energy-dispersive analysis of X-rays and thermal gravimetry under reducing conditions. Increased oxygen and Mn4+ contents were detected. X-ray diffraction and Rietveld refinement of X-ray data were carried out. Temperature dependent magnetization measurements were performed and the ferri-magnetic transition was identified at ≈100K. The ferri-magnetic moment was found to be ≈1μB and hysteretic magnetization vs applied field curves were obtained. Dielectric properties were measured using impedance spectroscopy. Two dielectric relaxation processes were detected, which were associated with grain boundary and bulk contributions. The Arrhenius plots of resistivity and the temperature dependent dielectric permittivity were obtained for the two relaxations by means of an equivalent circuit model based on a series of two parallel RC elements. © 2010 Elsevier Ltd. Fil: Díez, Alejandra. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Schmidt, Rainer. Universidad Complutense de Madrid; España Fil: Sagua, Aurora Estela. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Matesanz, Emilio. Universidad Complutense de Madrid; España Fil: Leon, Carlos. Universidad Complutense de Madrid; España Fil: Morán Emilio, E.. Universidad Complutense de Madrid; España

Lanthanum–lithium–sodium double chromates Li1−xNaxLa(CrO4)2 were prepared and analysed by means of admittance spectroscopy. Their a.c. conductivity parameters are correlated with structural details of high and low temperature forms of pure lanthanum–lithium double chromates. Lithium compounds show the lowest conductivity values and the highest activation energy for ion motion, while the sample Li0.5Na0.5La(CrO4)2 exhibits the highest conductivity 10−5 S cm−1 and the lowest activation energy 0.58 eV.

9 páginas, 6 figuras, 3 tablas.-- PACS number(s): 66.30.H-.-- et al., We report on the effect of grain size on the ionic conductivity of yttria-stabilized zirconia samples synthesized by ball milling. Complex impedance measurements, as a function of temperature and frequency are performed on 10 mol % yttria-stabilized zirconia nanocrystalline samples with grain sizes ranging from 900 to 17 nm. Bulk ionic conductivity decreases dramatically for grain sizes below 100 nm, although its activation energy is essentially independent of grain size. The results are interpreted in terms of a space-charge layer resulting from segregation of mobile oxygen vacancies to the grain-boundary core. The thickness of this space-charge layer formed at the grain boundaries is on the order of 1 nm for large micron-sized grains but extends up to 7 nm when decreasing the grain size down to 17 nm. This gives rise to oxygen vacancies depletion over a large volume fraction of the grain and consequently to a significant decrease in oxide-ion conductivity., We acknowledge financial support by Junta de Comunidades de Castilla-La Mancha through Project No. PAI-05-013, by CAM under Grant No. S2009/MAT-1756 (Phama), by Spanish MICINN through Grants No. MAT2008-06517-C02, No. MAT2008-06542-C04, and No. FIS2009-12964- C05-04, and Consolider Ingenio 2010 under Grant No. CSD2009-00013 (Imagine).