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Pela integração da inteligência competitiva nos Enterprise Information Systems (EIS)

Pozzebon,Marlei; Freitas,Henrique M. R. de; Petrini,Maira
Fonte: IBICT Publicador: IBICT
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1997 PT
Relevância na Pesquisa
36.89%
O objetivo deste artigo é evidenciar a importância da integração de um módulo de inteligência competitiva (coleta, organização e difusão da informação externa) nos sistemas de informações para o apoio à decisão das empresas, enriquecendo assim os Enterprise Information Systems (EIS). É a efetividade do gerente na busca da identificação ou da antecipação de problemas ou oportunidades, em um cenário de cada vez maiores pressões internas e principalmente externas. O propósito maior é fornecer amplo ambiente de oferta de informações internas e externas, formais e informais, informações sobre as percepções do mercado, informações envolvidas em análises e simulações, enfim, um ambiente integrador das informações disponíveis e relevantes para o sucesso da organização e que crie condições de proatividade para os usuários.

Aplicações de QCM, EIS e SPR na investigação de superfícies e interfaces para o desenvolvimento de (bio)sensores

Damos,Flavio Santos; Mendes,Renata Kelly; Kubota,Lauro Tatsuo
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 PT
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37.03%
The use of the quartz crystal microbalance process, electrochemical impedance spectroscopy and surface plasmon resonance for characterizing thin films and monitoring interfaces is presented. The theorical aspects of QCM, EIS and SPR are introduced and the main application areas are outlined. Future prospects of the combined applications of QCM, EIS and SPR methods in the studies of interfacial processes at surfaces are also discussed.

EIS and microstructural characterization of artificial nitrate patina layers produced at room temperature on copper and bronze

Bendezú H.,R. del P.; Gonçalves,R. P.; Neiva,A. C.; Melo,H. G. de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
Relevância na Pesquisa
37.13%
Artificial patina layers are often used to give final appearance and also to restore damaged old copper and bronze surfaces. The main inconvenient of this process is that it frequently requires surface heating or total immersion of the metallic object in the patina solution, which is sometimes impossible to accomplish, mainly with big outdoor exposed objects or ancient artefacts. In the present investigation the corrosion behaviour in NaCl solution of bare copper and bronze was compared with the response exhibited by samples of these metals covered with two different artificial nitrate-based patinas obtained at room temperature by dabbing a soaked cotton swab above their surfaces. The electrochemical techniques used to assess the response of the samples were electrochemical impedance spectroscopy (EIS) and anodic polarization curves. The anodic polarization responses have shown that, for short immersion times, the presence of the patina layer does not change the corrosion mechanism of the samples, which seems, as proposed in the literature, to be dominated by the diffusion of a soluble Cu complex to the bulk of the solution. However, EIS diagrams have evidenced differences between the responses of the bare and patina-treated samples. While in the formers the diagrams exhibited a low frequency diffusion controlled phenomenon...

Kinetic studies of HRP adsorption on ds-DNA immobilized on gold electrode surface by EIS and SPR

Ferreira,Danielle C. M; Mendes,Renata K; Kubota,Lauro T
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
36.89%
This paper describes the construction of a multicomponent film via layer-by-layer (LbL) method and the kinetic analysis of the interaction between horseradish peroxidase (HRP) enzyme on calf thymus double-stranded DNA layer on a modified gold surface. Surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS) are used to characterize the successful construction of the film on the gold surface. Surface plasmon resonance provided essential information for the study and characterization of protein and nucleic acid interaction and this method is label-free and monitors the interactions in real time. The kinetic studies determined by SPR of the horseradish peroxidase film formation on ds-DNA layer showed values of 24.7 L mol-1 s-1 and 1.2×10-3 s-1 for k a and k d, respectively. The Gibbs free energy obtained for the system was -23.1 kJ mol-1. The results obtained show that the interaction of the enzymes molecules on ds-DNA is kinetically and thermodynamically favourable and the interaction among the layers probably occurs mainly by attraction of opposite charges.

EIS investigation of the corrosion resistance of uncoated and coated Nd-Fe-B magnets in PBS solution

Martins,Emerson A; Oliveira,Mara C. L; Rossi,Jesualdo L; Costa,Isolda; Melo,Hercílio G. de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2011 EN
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37.03%
The aim of this work is to investigate the corrosion behavior of powder metallurgy produced Nd-Fe-B magnets and to evaluate the corrosion protection afforded by two different surface treatments: a phosphate conversion and a non-functional silane (BTSE) layer. The electrochemical tests were performed in a phosphate buffered solution (PBS) at neutral pH, which ionic concentration coincides with that of the human body. The corrosion behavior was monitored by means of electrochemical impedance spectroscopy (EIS) and anodic potentiodynamic polarization curves, and SEM-EDS analyses were used to monitor coating deposition. EIS response has evidenced a porous electrode behavior for the Nd-Fe-B magnets according to the de Levie theory. The results also indicated a good performance of the phosphate layer, whereas the BTSE layer did not improve the corrosion resistance of the magnets. The good anticorrosion performance of the phosphate layer was explained on the basis of the formation of an insoluble phosphate layer both on the electrode surface (identified by interference colors) and on the pore walls. Precipitation of insoluble Nd phosphate on the Nd-rich phase also contributes to the superior corrosion protection afforded by this coating.

CDW and CDW-EIS calculations for FDCSs in highly charged ion impact ionization of helium

Ciappina,M.; Cravero,W. R.
Fonte: Sociedade Brasileira de Física Publicador: Sociedade Brasileira de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2006 EN
Relevância na Pesquisa
36.89%
In this work we present fully differential cross sections (FDCS) calculations using CDW and CDW-EIS theories for helium single ionization by 100 MeV/amu and 2 MeV/amu C6+ and 3.6 MeV/amu Au24+ and Au53+ ions. We performed our calculations for different momentum transfers and ejected electron energies. We study the influence of the internuclear potential on the ejected electron spectra. We discuss different regimes where the internuclear interaction can or cannot be neglected. We compare our calculations with experimental data available. It is shown that for high impact energy and small momentum transfer, internuclear potential effects can be neglected in FDCSs.

Subcellular Localization of the Intracellular Survival-Enhancing Eis Protein of Mycobacterium tuberculosis

Dahl, John L.; Wei, Jun; Moulder, James W.; Laal, Suman; Friedman, Richard L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2001 EN
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27.4%
Mycobacterium tuberculosis is a facultative intracellular pathogen that has evolved the ability to survive and multiply within human macrophages. It is not clear how M. tuberculosis avoids the destructive action of macrophages, but this ability is fundamental in the pathogenicity of tuberculosis. A gene previously identified in M. tuberculosis, designated eis, was found to enhance intracellular survival of Mycobacterium smegmatis in the human macrophage-like cell line U-937 (J. Wei et al., J. Bacteriol. 182:377–384, 2000). When eis was introduced into M. smegmatis on a multicopy vector, sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the appearance of a unique 42-kDa protein band corresponding to the predicted molecular weight of the eis gene product. This band was electroeluted from the gel with a purity of >90% and subjected to N-terminal amino acid sequencing, which demonstrated that the 42-kDa band was indeed the protein product of eis. The Eis protein produced by M. tuberculosis H37Ra had an identical N-terminal amino acid sequence. A synthetic polypeptide corresponding to a carboxyl-terminal region of the deduced eis protein sequence was used to generate affinity-purified rabbit polyclonal antibodies that reacted with the 42-kDa protein in Western blot analysis. Hydropathy profile analysis showed the Eis protein to be predominantly hydrophilic with a potential hydrophobic amino terminus. Phase separation of M. tuberculosis H37Ra lysates by the nonionic detergent Triton X-114 revealed the Eis protein in both the aqueous and detergent phases. After fractionation of M. tuberculosis by differential centrifugation...

Activation of the eis gene in a W-Beijing strain of Mycobacterium tuberculosis correlates with increased SigA levels and enhanced intracellular growth

Wu, Shiping; Barnes, Peter F.; Samten, Buka; Pang, Xiuhua; Rodrigue, Sébastien; Ghanny, Saleena; Soteropoulos, Patricia; Gaudreau, Luc; Howard, Susan T.
Fonte: Society for General Microbiology Publicador: Society for General Microbiology
Tipo: Artigo de Revista Científica
Publicado em /04/2009 EN
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There is growing evidence that strains of Mycobacterium tuberculosis differ in pathogenicity and transmissibility, but little is understood about the contributory factors. We have previously shown that increased expression of the principal sigma factor, SigA, mediates the capacity of M. tuberculosis strain 210 to grow more rapidly in human monocytes, compared with other strains. Strain 210 is part of the widespread W-Beijing family of M. tuberculosis strains and includes clinical isolate TB294. To identify genes that respond to changes in SigA levels and that might enhance intracellular growth, we examined RNA and protein expression patterns in TB294-pSigA, a recombinant strain of TB294 that overexpresses sigA from a multicopy plasmid. Lysates from broth-grown cultures of TB294-pSigA contained high levels of Eis, a protein known to modulate host–pathogen interactions. DNA microarray analysis indicated that the eis gene, Rv2416c, was expressed at levels in TB294-pSigA 40-fold higher than in the vector control strain TB294-pCV, during growth in the human monocyte cell line MonoMac6. Other genes with elevated expression in TB294-pSigA showed much smaller changes from TB294-pCV, and the majority of genes with expression differences between the two strains had reduced expression in TB294-pSigA...

Mycobacterium tuberculosis Eis Regulates Autophagy, Inflammation, and Cell Death through Redox-dependent Signaling

Shin, Dong-Min; Jeon, Bo-Young; Lee, Hye-Mi; Jin, Hyo Sun; Yuk, Jae-Min; Song, Chang-Hwa; Lee, Sang-Hee; Lee, Zee-Won; Cho, Sang-Nae; Kim, Jin-Man; Friedman, Richard L.; Jo, Eun-Kyeong
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN
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27.4%
The “enhanced intracellular survival” (eis) gene of Mycobacterium tuberculosis (Mtb) is involved in the intracellular survival of M. smegmatis. However, its exact effects on host cell function remain elusive. We herein report that Mtb Eis plays essential roles in modulating macrophage autophagy, inflammatory responses, and cell death via a reactive oxygen species (ROS)-dependent pathway. Macrophages infected with an Mtb eis-deletion mutant H37Rv (Mtb-Δeis) displayed markedly increased accumulation of massive autophagic vacuoles and formation of autophagosomes in vitro and in vivo. Infection of macrophages with Mtb-Δeis increased the production of tumor necrosis factor-α and interleukin-6 over the levels produced by infection with wild-type or complemented strains. Elevated ROS generation in macrophages infected with Mtb-Δeis (for which NADPH oxidase and mitochondria were largely responsible) rendered the cells highly sensitive to autophagy activation and cytokine production. Despite considerable activation of autophagy and proinflammatory responses, macrophages infected with Mtb-Δeis underwent caspase-independent cell death. This cell death was significantly inhibited by blockade of autophagy and c-Jun N-terminal kinase-ROS signaling...

Thermostable Hexameric Form of Eis (Rv2416c) Protein of M. tuberculosis Plays an Important Role for Enhanced Intracellular Survival within Macrophages

Ganaie, Arsheed A.; Lella, Ravi K.; Solanki, Rahul; Sharma, Charu
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 16/11/2011 EN
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27.45%
Eis protein is reported to enhance the intracellular survival of Mycobacterium tuberculosis in human macrophages. Eis protein is not only known to skew away the immunity by disturbing the protective TH1 response, but aminoglycoside acetyltransferase activity of Eis is reported to regulate autophagy, inflammation and cell death. Here we have gained insight into the structure-function properties of Eis. Eis protein is a hexameric αβ protein. Although urea and guanidinium hydrochloride (GdmCl) was found to induce one-step unfolding of Eis but size exclusion chromatography showed that GdmCl treated Eis maintained its hexameric form. SDS-PAGE assay confirmed that hexameric form of Eis is partially stable to SDS and converts into trimers and monomers. Out of these three forms, aminoglycoside acetyltransferase activity is found to be associated only with hexamers. The Tm of Eis was found to be ∼75°C. Aminoglycoside acetyltransferase Eis demonstrated remarkable heat stability retaining >80% of their activity at 70°C which falls down to ∼50% at 75°C and is completely inactive at 80°C. Further, intracellular survival assay with heated samples of M. smegmatis harboring eis gene of M. tuberculosis H37Rv demonstrated a possible role for the thermostability associated with Eis protein in the enhanced intracellular survival within macrophages. In sum...

Mycobacterium tuberculosis Eis protein initiates suppression of host immune responses by acetylation of DUSP16/MKP-7

Kim, Kyoung Hoon; An, Doo Ri; Song, Jinsu; Yoon, Ji Young; Kim, Hyoun Sook; Yoon, Hye Jin; Im, Ha Na; Kim, Jieun; Kim, Do Jin; Lee, Sang Jae; Kim, Ki-Hye; Lee, Hye-Mi; Kim, Hie-Joon; Jo, Eun-Kyeong; Lee, Jae Young; Suh, Se Won
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.47%
The intracellular pathogen Mycobacterium tuberculosis (Mtb) causes tuberculosis. Enhanced intracellular survival (Eis) protein, secreted by Mtb, enhances survival of Mycobacterium smegmatis (Msm) in macrophages. Mtb Eis was shown to suppress host immune defenses by negatively modulating autophagy, inflammation, and cell death through JNK-dependent inhibition of reactive oxygen species (ROS) generation. Mtb Eis was recently demonstrated to contribute to drug resistance by acetylating multiple amines of aminoglycosides. However, the mechanism of enhanced intracellular survival by Mtb Eis remains unanswered. Therefore, we have characterized both Mtb and Msm Eis proteins biochemically and structurally. We have discovered that Mtb Eis is an efficient Nɛ-acetyltransferase, rapidly acetylating Lys55 of dual-specificity protein phosphatase 16 (DUSP16)/mitogen-activated protein kinase phosphatase-7 (MKP-7), a JNK-specific phosphatase. In contrast, Msm Eis is more efficient as an Nα-acetyltransferase. We also show that Msm Eis acetylates aminoglycosides as readily as Mtb Eis. Furthermore, Mtb Eis, but not Msm Eis, inhibits LPS-induced JNK phosphorylation. This functional difference against DUSP16/MKP-7 can be understood by comparing the structures of two Eis proteins. The active site of Mtb Eis with a narrow channel seems more suitable for sequence-specific recognition of the protein substrate than the pocket-shaped active site of Msm Eis. We propose that Mtb Eis initiates the inhibition of JNK-dependent autophagy...

The aminoglycoside multi-acetylating activity of the enhanced intracellular survival (Eis) protein from Mycobacterium smegmatis and its inhibition

Chen, Wenjing; Green, Keith D.; Tsodikov, Oleg V.; Garneau-Tsodikova, Sylvie
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.53%
The enhanced intracellular survival (Eis) protein improves Mycobacterium smegmatis (Msm) survival in macrophages and functions as the acetyltransferase responsible for kanamycin A resistance, a hallmark of extensively drug-resistant (XDR) tuberculosis, in a large number of Mycobacterium tuberculosis (Mtb) clinical isolates. We recently demonstrated that Eis from Mtb (Eis_Mtb) efficiently multi-acetylates a variety of aminoglycoside (AG) antibiotics. Here, to gain insight into the origin of substrate selectivity of AG multi-acetylation by Eis, we analyzed AG acetylation by Eis_Msm, investigated its inhibition, and compared these functions to those of Eis_Mtb. Even though for several AGs the multi-acetylation properties of Eis_Msm and Eis_Mtb are similar, there are three major differences: (i) Eis_Msm di-acetylates apramycin, a conformationally constrained AG, which Eis_Mtb cannot modify, (ii) Eis_Msm tri-acetylates paromomycin, which can be only di-acetylated by Eis_Mtb, and (iii) Eis_Msm only mono-acetylates hygromycin, a structurally unique AG that is di-acetylated by Eis_Mtb. Several non-conserved amino acid residues lining the AG-binding pocket of Eis are likely responsible for these differences between the two Eis homologs. Specifically...

Biochemical and structural analysis of aminoglycoside acetyltransferase Eis from Anabaena variabilis†

Pricer, Rachel E.; Houghton, Jacob L.; Green, Keith D.; Mayhoub, Abdelrahman S.; Garneau-Tsodikova, Sylvie
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 30/10/2012 EN
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27.45%
The Mycobacterium tuberculosis enhanced intracellular survival (Eis_Mtb) protein is a clinically important aminoglycoside (AG) multi-acetylating enzyme. Eis homologues are found in a variety of mycobacterial and non-mycobacterial species. Variation of the residues lining the AG-binding pocket and positions of the loops bearing these residues in the Eis homologues dictates the substrate specificity and, thus, Eis homologues are Nature-made tools for elucidating principles of AG recognition by Eis. Here, we demonstrate that the Eis from Anabaena variabilis (Eis_Ava), the first non-mycobacterial Eis homologue reported, is a multi-acetylating AG-acetyltransferase. Eis_Ava, Eis from Mycobacterium tuberculosis (Eis_Mtb), and Eis from Mycobacterium smegmatis (Eis_Msm) have different structures of their AG-binding pockets. We perform comparative analysis of these differences and investigate how they dictate the substrate and cosubstrate recognition and acetylation of AGs by Eis.

Redesign of substrate specificity and identification of aminoglycoside binding residues of Eis from Mycobacterium tuberculosis

Jennings, Benjamin C.; Labby, Kristin J.; Green, Keith D.; Garneau-Tsodikova, Sylvie
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.49%
The upsurge of drug-resistant tuberculosis (TB) is an emerging global problem. Increased expression of the enhanced intracellular survival (Eis) protein is responsible for clinical resistance to aminoglycoside (AG) antibiotics in Mycobacterium tuberculosis. Eis from M. tuberculosis (Eis_Mtb) and from M. smegmatis (Eis_Msm) both function as acetyltransferases capable of acetylating multiple amines of many AGs; however, these Eis homologs differ in AG substrate preference and number of acetylated amine groups per AG. The AG binding cavity of Eis_Mtb is divided into two narrow channels, whereas Eis_Msm contains one large cavity. Five bulky residues lining one of the AG binding channels of Eis_Mtb, His119, Ile268, Trp289, Gln291, and Glu401, have significantly smaller counterparts in Eis_Msm, Thr119, Gly266, Ala287, Ala289, and Gly401, respectively. To identify the residue(s) responsible for AG binding in Eis_Mtb and functional differences from Eis_Msm, we have generated single, double, triple, quadruple, and quintuple mutants of these residues in Eis_Mtb into their Eis_Msm counterparts and tested their acetylation activity with three structurally diverse AGs: kanamycin A (KAN), paromomyin (PAR), and apramycin (APR). We show that the penultimate C-terminal residue Glu401 plays a critical role in the overall activity of Eis_Mtb. We also demonstrate that the identities of residues Ile268...

Numerical Modelling of Ice Microstructures; Numerische Modellierung von Mikrostrukturen in Eis

Rößiger, Jens
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
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37.13%
Accurate modelling of ice mechanical behaviour under natural conditions is important for climate reconstruction and prediction, as well as for other scientific questions. It influences estimates of sea level changes and interpretation of past climate variations or signals recorded in ice cores. Better insight into the behaviour and constitutive equations of ice is imperative to improve modelling of glaciers and ice sheets. The aim of this thesis was to develop numerical models to simulate the microstructural behaviour of ice, as observed in nature and experiments. Numerical simulations were carried out with the numerical modelling platform "Elle", for which many new routines and algorithms were developed and implemented in this project. In a first series of models static grain growth and simultaneous grain-size reduction by rotational recrystallization was investigated. Well-established theory for static grain growth predicts a linear increase of the grain area with time for ice. The growth rate is then determined by the growth parameter k, which is commonly assumed to be a temperature and material-dependent constant. However, the simulations show that k also depends on the microstructure and can thus vary as the microstructure evolves. Experiments that start with non-equilibrium microstructures potentially yield growth parameters (k and the growth exponent...

Electrochemical Stability and Bioactivity Evaluation of Ti6Al4V Surface Coated with Thin Oxide by EIS for Biomedical Applications

Gugelmin,Bruno Schneider; Santos,Luciane Sopchenski; Ponte,Haroldo de Araújo; Marino,Cláudia Eliana Bruno
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
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36.89%
To improve the implants biocompatibility many surface modifications were proposed. Investigations about the surface modification on Ti alloys by anodic oxidation are reported. This research presents a study on the stability of thin titanium dioxide grown by potentiodynamic method on Ti6Al4V surfaces up to 5.0 V. Its bioactive surface in phosphate buffer solution (PBS) and the oxide stability after immersion in artificial blood media were measured by Electrochemical Impedance Spectroscopy (EIS). Hydroxyapatite (HAP) presence was evaluated using simulated body fluid (SBF) with different immersion times. The oxides and HAP presence were analyzed by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The oxide stability was confirmed with low dissolution rates where the Rp was around 106Ω.cm2. The results showed the TiO2 was compact and thin oxide that could prevent the severe corrosion processes and improve in few days the physical-chemical interaction of the Ti alloys with bone in physiological media.

Underflight calibration of SOHO/CDS and Hinode/EIS with EUNIS-07

Wang, Tongjiang; Thomas, Roger J.; Brosius, Jeffrey W.; Young, Peter R.; Rabin, Douglas M.; Davila, Joseph M.; Del Zanna, Giulio
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/09/2011
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27.36%
Flights of Goddard Space Flight Center's Extreme-Ultraviolet Normal-Incidence Spectrograph (EUNIS) sounding rocket in 2006 and 2007 provided updated radiometric calibrations for SOHO/CDS and Hinode/EIS. EUNIS carried two independent imaging spectrographs covering wavebands of 300-370 A in first order and 170-205 A in second order. After each flight, end-to-end radiometric calibrations of the rocket payload were carried out in the same facility used for pre-launch calibrations of CDS and EIS. During the 2007 flight, EUNIS, SOHO CDS and Hinode EIS observed the same solar locations, allowing the EUNIS calibrations to be directly applied to both CDS and EIS. The measured CDS NIS 1 line intensities calibrated with the standard (version 4) responsivities with the standard long-term corrections are found to be too low by a factor of 1.5 due to the decrease in responsivity. The EIS calibration update is performed in two ways. One is using the direct calibration transfer of the calibrated EUNIS-07 short wavelength (SW) channel. The other is using the insensitive line pairs, in which one member was observed by EUNIS-07 long wavelength (LW) channel and the other by EIS in either LW or SW waveband. Measurements from both methods are in good agreement...

A Systematic Process for Addressing Incomplete Information in an EIS

Routhier, Michael
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Relatório
Publicado em 25/11/2012 EN_US
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The issue of missing or incomplete information arises in many National Environmental Policy Act (NEPA) processes. Council on Environmental Quality (CEQ) regulations provide some guidance on how to address incomplete information at 40 C.F.R.§1502.22, but this provision can be difficult to interpret and is frequently misapplied. Departmental and agency implementing regulations tend to provide little instructions regarding missing or incomplete information, and there is scant applicable case law. Federal agencies and NEPA practitioners are left with inadequate guidance on this difficult and often controversial issue. Uncertainty about how to address missing or incomplete information can weaken NEPA analyses, obfuscate important environmental issues and also undermine the legal defensibility of NEPA documents and the agency decisions they support. This paper proposes a systematic process for addressing incomplete information in Environmental Impact Statements developed pursuant to NEPA. This solution flows from careful interpretation of relevant provisions of NEPA and CEQ regulations, in particular CEQ regulations at 40 C.F.R.§1502.22. The product of this effort is a sequential process that is simple enough to illustrate in the form a flow chart...

EIS diagnostics of aged Li-ion batteries

Plancha, Maria João; Luz, Paulo P. da; Rangel, C. M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
37.13%
High-power batteries with long cycling life and adequate storage behaviour are needed as energy sources devices for (hybrid) electric vehicles and lithium-ion rechargeable cells are the most promising candidates. In this work, Li-ion cells with a nominal capacity of 10 Ah were studied. Electrochemical impedance spectroscopy (EIS) was used for studying the cycling ageing effect on discharge capacity fade. EIS measurements were conducted in a galvanostatic mode, by means of a Solartron Electrochemical Interface 1286 and a Solartron FRA 1250 controlled by Zplot from Scribner Associates. Scanning frequency ranged from 600 Hz to 0.005 Hz and the ac amplitude was set to 100 mA. An equivalent circuit complex non-linear least squares fitting procedure was used for spectra analyses. Cell charge transfer and film resistances were estimated at several cycle life stages and its evolution on cycle number was analysed. Capacity losses were estimated after 300, 600 and 1200 cycles at C/1 discharge rate and were found to be 5.8, 7.5 and 16.8% of the initial capacity, respectively. EIS data revealed that the major factor responsible for the observed capacity fade was the cell’s charge transfer resistance (Rct) increase following the opposite tendency of the discharge capacity values with cycle number. Very little change can be attributed to film resistances as a result of ageing by cycling. The SEI layer thickness appeared to increase from 0 to 300 cycles remaining almost constant up to 1200 cycles. The effect of a high storage temperature on the performance of the sealed commercial batteries was evaluated by means of discharge capacity measurements and impedance behaviour. The thermal ageing conditions were applied over time and the results were interpreted taking into account the cell’s state of charge (SOC). Before storage at 45 oC...

EIS Study of Amine Cured Epoxy-silica-zirconia Sol-gel Coatings for Corrosion Protection of the Aluminium Alloy EN AW 6063

Fontinha,I. Rute; Salta,M. Manuela; Zheludkevich,Mikhail L; Ferreira,Mário G.S.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2013 EN
Relevância na Pesquisa
36.89%
The organic-inorganic hybrid sol-gel films, the structure of which comprises interconnected inorganic and organic networks have been reported as an environmentally friendly anti-corrosion pre-treatment for several metals, including aluminium alloys. In this paper, an epoxy-silica-zirconia hybrid sol-gel coating was synthesized from glycidoxypropyltrimethoxysilane (GPTMS) and zirconium npropoxide (TPOZ) precursors and applied to EN AW-6063 alloy by dip-coating. To promote the organic network formation through the epoxy group polymerization at room temperature, two types of amine crosslinkers were added during synthesis: diethylenetriamine (DETA), in different concentrations, and a tri-functional aminosilane. The evolution of the curing process and the corrosion behaviour of the coated aluminium alloy specimens were evaluated by Electrochemical Impedance Spectroscopy (EIS) in 0.5 M NaCl. The morphology and surface chemistry of the hybrid coatings were characterized by Energy Dispersive Spectroscopy (EDS) coupled with Scanning Electron Microscopy (SEM) and by Fourier Transform Infrared Spectroscopy (FTIR). The results obtained revealed that the sol-gel coatings with lower amine ratios required longer curing times, but showed the best anticorrosive performance with time. The increase in amine concentration has led to a more cross linked organic network...