Electrode

Capacitive deionization (CDI) has attracted the interest of the community investigating water treatment technologies since the mid-1960s. The technology is based on the recognition that high-surface-area electrodes, when electrically charged, can quantitatively adsorb ionic components from water, thereby resulting in desalination. The article reviews the theoretical and technological background of CDI, the history of its development, and past and present attempts towards scaling up and commercialization. It also provides a critical review of the advantages and limitations of the technology. In addition, further research approaches necessary to render CDI a mature and competitive technology for the treatment of brackish and surface waters are outlined.

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Carbon supported PtRu alloys were prepared by impregnation of Pt and Ru precursors on a porous carbon support, followed by reduction of the metals with Na S O . After reduction, the samples were thermal treated in argon up to 7008C. The samples were 2 2 4 characterized by atomic absorption (AAS) and X-ray diffraction (XRD) measurements. Before thermal treatment only carbon reflexions were visible in XRD pattern. The reflexions of face centered cubic (f.c.c.) PtRu alloy were revealed in XRD pattern starting from thermal treatment at 3008C. No hexagonal close packed (h.c.p.) RuPt reflexions were detected. During thermal treatment, part of Ru reacted with sulphur forming RuS . Ru content in the alloy increased with increasing thermal treatment temperature. The results indicated that, first, 2 f.c.c. Pt with few Ru alloyed was formed, then, with increasing thermal treatment temperature, part of Ru atoms present in the sample in an amorphous form entered in the crystal structure of the platinum by a diffusion-controlled mechanism. Also after thermal treatment at high temperatures there was a large part of unalloyed Ru, with only about 49% of the Ru alloyed with the Pt. PtRu particle size was in the range 15-20 nm.

Los electrodos de grafito artificial son un estándar en la producción de acero en hornos eléctricos. El grafito artificial posee una alta conductividad eléctrica y elevada resistencia al choque térmico que lo hacen imprescindible para este uso. El consumo medio ha sido cuantificado, para un gran número de acerías eléctricas del grupo ArcelorMittal, en 1,43 kg/t [1]. La producción de acero crudo en acerías eléctricas fue en el año 2010 de 406 Mt. Podría estimarse el consumo de electrodos para hornos eléctricos en el orden de las 600.000 t/año; a esto se le debería sumar el consumo en los hornos cuchara. Entre los principales fabricantes están GrafTech International, SGL Group, Showa Denko Carbon, Tokai Carbon, HEG Ltd., Superior Graphite, UK CG, Beijing Fangda Carbon Tech, Chengdu Ronguang Carbon, Fangda Carbon New
Material, Fushun Carbon, Guangshan Shida Carbon, Hefei Carbon, GES (China), Jilin Carbon Import & Export. Es un mercado competitivo en costos, calidad y servicio, con estrategias diferenciadas y en el que ha habido en la última década un proceso importante de fusiones y adquisiciones. Una parte de las empresas mencionadas tiene sitios de producción en varios países. Se trata de una industria madura, que utiliza en general sistemas de producción modernos, con importante
grado de automatización, capaces de
formular electrodos con un alto grado de
repetitividad.
En el Cuadro 1 se presentan algunas fechas
importantes en el desarrollo y aplicación
de los electrodos de grafito [2].
Las materias primas para la producción
de los electrodos son el coque de petróleo,
preferentemente del tipo denominado
aguja y la brea de alquitrán de hulla.
Estos materiales se mezclan y procesan
a alta temperatura en varios pasos, hasta
obtener el grafito sintético. Es un producto
con un alto valor agregado energético.
En los párrafos siguientes se presentan
detalles sobre las materias primas utilizadas,
el proceso de fabricación, el diseño
de los electrodos y su aplicación, desde
el punto de vista de algunas de las novedades
tecnológicas que se han introducido
en las últimas décadas.
Cabe mencionar que los avances en las
materias primas, el proceso de fabricación
y la performance en uso son lentos.
El proceso de producción de los electrodos
es largo, de hasta dos meses; a esto
debe sumarse el tiempo de prueba en la
acería para saber si una cierta formulación
presenta ventajas, donde un gran
número de variables puede influir sobre
los resultados [4].

Treatment of textile wastewaters by electrocoagulation using iron and of aluminum electrode materials has been investigated in this paper. The effects of relevant wastewater characteristics such as conductivity and pH, and important process variables such as current density and operating time on the chemical oxygen demand (COD) and turbidity removal efficiencies have been explored. Furthermore, the electrode and energy consumptions for each electrode have been calculated. The results show that iron is superior to aluminum as sacrificial electrode material, from COD removal efficiency and energy consumption points.

This paper compares the resolution and efficiency of 2D resistivity imaging survey with eight electrode arrays by numerical simulations. The arrays analysed include the pole-pole (PP), pole-dipole (PD), pole-bipole (PB), Wenner-α (WN), Schlumberger (SC), dipole-dipole (DD), Wenner-β (WB), γ-array (GM), gradient (GD) and midpoint-potential-referred measurements (MPR) arrays. Five synthetic geological models that simulate a buried channel, narrow conductive dyke, narrow resistive dyke, dipping blocks and covered waste ponds were used to examine the surveying efficiency (anomaly effects, signal-noise ratios) and the imaging capabilities of these arrays. Also, the response to variations in data density and noise sensitivities of these electrode configurations were investigated using the robust inversion and smoothness-constrained least-squares ( 2 L -norm) inversion for the five synthetic models. The results show that: (1) GM and WN have less noise contamination than other electrode arrays;

The aim of this study is to detect epileptic seizure in EEG signals using a hybrid system based on decision tree classifier and fast Fourier transform (FFT). The present study proposes a hybrid system with two stages: feature extraction using FFT and decision making using decision tree classifier. The detection of epileptiform discharges in the electroencephalogram (EEG) is an important part in the diagnosis of epilepsy. All data set were obtained from EEG signals of healthy subjects and subjects suffering from epilepsy diseases. For healthy subjects is background EEG (scalp) with open eyes and for epileptic patients correspond to a seizure recorded in hippocampus (epileptic focus) with depth electrodes. The evolution of proposed system was conducted using k-fold cross-validation, classification accuracy, and sensitivity and specificity values. We have obtained 98.68% and 98.72% classification accuracies using 5-and 10-fold cross-validation. The stated results show that the proposed method could point out the ability of design of a new intelligent assistance diagnosis system.

Breaking the skin when applying scalp electroencephalographic (EEG) electrodes creates the risk of infection from blood-born pathogens such as HIV, Hepatitis-C, and Creutzfeldt-Jakob Disease. Modern engineering principles suggest that excellent EEG signals can be collected with high scalp impedance (≈ 40 kΩ) without scalp abrasion. The present study was designed to evaluate the effect of electrode-scalp impedance on EEG data quality.

Metal corrosion is very important factor for redox reaction during cell reactions. So that it has been studied in this research work. When metals react, they give away electrons and form positive ions. This particular topic describes how a metal form hydrated ions in solution. It can be considered the case of Magnesium and Copper in water. It can be compared the following two reactions how these two changes take place: Mg (S) Mg 2+ (aq) + 2e-Cu (S) Cu 2+ (aq) + 2e-It is known that magnesium is more reactive than copper. The first reaction happens much more readily than the second one. Now it will be tried to express this with some numbers.

Objective: Electroencephalography (EEG) is an important tool for studying the temporal dynamics of the human brain's large-scale neuronal circuits. However, most EEG applications fail to capitalize on all of the data's available information, particularly that concerning the location of active sources in the brain. Localizing the sources of a given scalp measurement is only achieved by solving the so-called inverse problem. By introducing reasonable a priori constraints, the inverse problem can be solved and the most probable sources in the brain at every moment in time can be accurately localized.

The main goal of this study is to investigate the effects of alternating current (AC) on dye removal from aqueous solutions by electrocoagulation (EC). An EC system with parallel-connected aluminium electrodes was operated in batch mode. Two different aqueous dye solutions were used: one was obtained from Dianix Yellow CC (DY) and the other was obtained using Procion Yellow (PY). The experiments employing direct current (DC) were carried out using a DC power supply. The AC experiments were conducted using rectangular wave, which is produced with an adjustable time relay connected to the output of DC power supply. This current is called alternating pulse current (APC) in order to refer AC system in this study. Total organic carbon (TOC) and dye removal efficiencies were measured to assess treatment efficiency. Operating cost was calculated for both power supply systems and alternating pulse current was found superior to direct current for the treatment of reactive and disperse dyes used in this study.

The treatment and disposal of sewage sludge is one of the most problematical issues affecting wastewater treatment in the developed world. The traditional outlets for sewage sludge are to spread it on agricultural land, or to form a cake for deposit to landfill or incineration. In order to create a sludge cake, water must be removed. Existing dewatering technology based on pressure can only remove a very limited amount of this water because of the way in which water is bound to the sludge particles or flocs. Several researchers have shown that electrokinetic dewatering of sludge is more efficient than conventional hydraulically driven methods. This involves the application of a dc voltage across the sludge, driving water under an electrical gradient from positive (anode) electrode to negative (cathode) electrode. However, there have been several reasons why this technique has not been adopted in practice, not least because the, normally metallic, anode rapidly dissolves due to the acidic environment created by the electrolysis of water. This paper will describe experimentation using electrokinetic geosynthetics (EKG): polymer-based materials containing conducting elements. These have been used to minimise the problem of electrode corrosion and create a sludge treatment system that can produce dry solids contents in excess of 30%. It will suggest different options for the treatment of sludges both in situ in sludge lagoons and windrows, and ex situ as a treatment process.

As the most successful neural prosthesis, cochlear implants have provided partial hearing to more than 120,000 persons worldwide; half of which being pediatric users who are able to develop nearly normal language. Biomedical engineers have played a central role in the design, integration and evaluation of the cochlear implant system, but the overall success is a result of collaborative work with physiologists, psychologists, physicians, educators, and entrepreneurs. This review presents broad yet in-depth academic and industrial perspectives on the underlying research and ongoing development of cochlear implants. The introduction accounts for major events and advances in cochlear implants, including dynamic interplays among engineers, scientists, physicians, and policy makers. The review takes a system approach to address critical issues from design and specifications to integration and evaluation. First, the cochlear implant system design and specifications are laid out. Second, the design goals, principles, and methods of the subsystem components are identified from the external speech processor and radio frequency transmission link to the internal receiver, stimulator and electrode arrays. Third, system integration and functional evaluation are presented with respect to safety, reliability, and challenges facing the present and future cochlear implant designers and users. Finally, issues beyond cochlear implants are discussed to address treatment options for the entire spectrum of hearing impairment as well as to use the cochlear implant as a model to design and evaluate other similar neural prostheses such as vestibular and retinal implants.

To obtain a high quality EMG acquisition, the signal must be recorded as far away as possible from muscle innervations and tendon zones, which are known to shift during dynamic contractions. This study describes a methodology, using commercial bipolar electrodes, to identify better electrode positions for superficial EMG of lower limb muscles during dynamic contractions. Eight female volunteers participated in this study. Myoelectric signals of the vastus lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles were acquired during maximum isometric contractions using bipolar electrodes. The electrode positions of each muscle were selected assessing SENIAM and then, other positions were located along the length of muscle up and down the SENIAM site. The raw signal (density), the linear envelopes, the RMS value, the motor point site, the position of the IZ and its shift during dynamic contractions were taken into account to select and compare electrode positions. For vastus lateralis and peroneus longus, the best sites were 66% and 25% of muscle length, respectively (similar to SENIAM location). The position of the tibialis anterior electrodes presented the best signal at 47.5% of its length (different from SENIAM location). The position of the gastrocnemius medialis electrodes was at 38% of its length and SENIAM does not specify a precise location for signal acquisition. The proposed method should be considered as another methodological step in every EMG study to guarantee the quality of the signal and subsequent human movement interpretations.

Treatment of textile wastewaters by electrocoagulation using iron and of aluminum electrode materials has been investigated in this paper. The effects of relevant wastewater characteristics such as conductivity and pH, and important process variables such as current density and operating time on the chemical oxygen demand (COD) and turbidity removal efficiencies have been explored. Furthermore, the electrode and energy consumptions for each electrode have been calculated. The results show that iron is superior to aluminum as sacrificial electrode material, from COD removal efficiency and energy consumption points.

Objective: In recent years, a promising tool has been introduced which allows the co-registration of electroencephalographic (EEG) activity during brain transcranial magnetic stimulation (TMS). The aims of the present study are to identify eventual stimulus-related artefacts, and to confirm and extend previous EEG/TMS findings about the possible networks generating EEG responses evoked by TMS. Methods: Focal TMS was delivered to the left primary motor cortex (MI), with different coils (real and sham) and orientations (45 and 1358 in respect to the sagittal plane), in six healthy subjects. EEG and motor evoked potentials (MEPs) were simultaneously recorded from 19 scalp electrodes. Results: TMS, with coil oriented at 458, induced EEG responses characterized by a sequence of positive deflections peaking at approximately 14, 30, 60 and 190 ms and negative deflections peaking at approximately 10, 18, 40 and 100 ms post-TMS. The negative components were recorded at the recording electrode corresponding with the stimulation site (N10, N18), as well as at recording electrodes over the frontal region of the contralateral, unstimulated, hemisphere (N40) and bilaterally over the central hemispheres with its maximal representation at the stimulation site (N100). The positive components were instead detected at the frontal region of the right, unstimulated, hemisphere (P14), over the central electrodes Cz, Fz and the frontal region of the right hemisphere (P30), at the stimulation site (P60), and over the frontal regions of both hemispheres. When TMS was delivered with the coil oriented at 1358, no MEPs were recorded from the right target muscle. Nonetheless, all the TMS-induced EEG components were still evoked apart from the N20-P30. Finally, TMS with the sham coil over left MI did not induce either significant EEG responses or MEPs. Conclusions: In conclusion, the TMS evoked components we have obtained by recording in continuous mode strikingly fit with those already described by other authors for both their latencies and the spatio-temporal pattern of scalp distribution. Significance: This experiment is a farther validation of the combined EEG/TMS recording technique as a promising tool for experimental and clinical purposes.

Oily wastewaters are the most important discharges of gas refineries from an environmental point-of-view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)(-1) to 11.057 kWh (kg COD removal)(-1) using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nea...

An azimuthal resistivity survey was conducted at the transition zone between the desert area and the cultivated land near Lake Qaroun, Egypt. This area has been affected by an east-west trending fault system as indicated from the surface geology. Apparent resistivity values were plotted along azimuth on a polar diagram. Resistivity anomalies, for most of the AB/2 values with long axes strike in a direction parallel to the contact between the desert and cultivated lands, indicate the presence of electrical macro-anisotropy, mainly due to the faulting effect, at this area. Vertical electrical soundings (VES) and transient electromagnetic (TEM) measurements were conducted at eight stations along a line that crosses the boundary between the desert and cultivated land. Joint inversion of VES-TEM data was successfully used for identification of the subsurface lithostratigraphic succession and demonstrated the effect of the fault zone on the investigated subsurface medium. Apparent anisotropy coefficients at all current electrode spacings were calculated, plotted against AB/2 values and compared with the geoelectrical cross section. The effect of the fault zone was detected at AB/2 spacings equal to 100 m and extended downward and is largely related to the depth of the fault, as indicated in the constructed cross section.

Objective: This study investigated differences in coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (ADHD) -with the typical EEG profile (increased h and decreased b activity), and with excess b activity -and a normal control group. Methods: Thirty-four children with ADHD were included in each of the typical and excess b groups, and were age and sex matched with 34 control subjects. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the d, h, a and b bands. Results: In comparison to the controls, the typical ADHD group primarily had increased intrahemispheric h and b coherence at shortmedium inter-electrode distances, and increased interhemispheric coherence for h in the frontal and central/parietal/occipital regions. Their laterality effect for interhemispheric short-medium inter-electrode distances was reduced in the h band. Differences between the excess b group and the control group were primarily found in laterality of the intrahemispheric h coherence at short-medium electrode distances, and increased interhemispheric h coherence in the frontal regions. Reduced d coherence in the temporal regions was also found. Conclusions: These results suggest that ADHD children with excess b power have an underlying brain dysfunction in the frontal lobes which is found in common with children with the typical EEG profile. However a number of qualitative differences exist which could be associated with other aspects of the ADHD diagnosis or another comorbid condition. Significance: This is the first study to investigate EEG coherence in ADHD children who have increased b power.

During the AC electrokinetic manipulation of particles in suspension on microelectrode structures, strong frequency-dependent fluid flow is observed. The fluid movement is predominant at frequencies below the reciprocal charge relaxation time, with a reproducible pattern occurring close to and across the electrode surface. This paper reports measurements of the fluid velocity as a function of frequency and position across the electrode. Evidence is presented indicating that the flow occurs due to electroosmotic stress arising from the interaction of the electric field and the electrical double layer on the electrodes. The electrode polarization plays a significant role in controlling the frequency dependence of the flow.

An inexpensive microporous polyaniline (PANI) is used as a substitute for platinum to construct the counter electrode in dye-sensitized solar cells (DSSCs). The PANI counter electrode with microporosity and a size diameter of about 100 nm possesses lower charge-transfer resistance and higher electrocatalytic activity for the I À 3 =I À redox reaction than Pt electrode does. The overall energy conversion efficiency of the DSSC with PANI counter electrode reaches 7.15%, which is higher than that of the DSSC with Pt counter electrode. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow PANI electrode to be a credible alternative for DSSCs.

Cyclic voltammetry, hydrogen permeation tests and electrochemical impedance spectroscopy measurements were combined to study the mechanism for hydrogen evolution reaction on X-70 pipe steel in near-neutral pH solution. It is found that hydrogen evolution reaction is dominated by the reduction of water molecules, followed by either an electrochemical hydrogen recombination reaction or a hydrogen absorption reaction. The near-neutral pH environment is capable of generating catalytic surface effect on hydrogen evolution on the pipe steel. The increasing dissolution of the cathodically pre-polarized steel could be due to the enhanced activation of the steel, rather than the increasing amount of hydrogen atoms in the steel. These results provide mechanistic information to understand the nearneutral pH stress corrosion cracking of pipelines.

Performance of electrocoagulation system for the removal of copper from synthetic wastewater was investigated using aluminum electrode pair at four operational parameters: copper concentration (2.5-32.5 mg L − 1 ), pH (5-9), voltage (6-18 V) and treatment time (5-25 min). Metal removal efficiency and energy consumption were monitored as responses. Experiments were conducted as per center composite design, and the data was used for model building employing response surface methodology (RSM) and artificial neural network approach (ANN). Multi objective optimization for maximizing the copper removal efficiency and minimizing the energy consumption was carried out using genetic algorithm (GA) over the ANN model. The optimization procedure resulted in the creation of nondominated optimal points which gave an insight regarding the optimal operating conditions of the process.

Combination of electrodes, such as aluminum and iron in a single electrochemical cell provide an alternative method for removal of arsenic from water by electrocoagulation. The removal process has been studied with a wide range of arsenic concentration (1-1000 ppm) at different pH (4-10). Analysis of the electrochemically generated by-products by XRD, XPS, SEM/EDAX, FT-IR, and Mössbauer Spectroscopy revealed the expected crystalline iron oxides (magnetite (Fe 3 O 4 ), lepidocrocite (FeO(OH)), iron oxide (FeO)) and aluminum oxides (bayerite (Al(OH) 3 ), diaspore (AlO(OH)), mansfieldite (AlAsO 4 ·2(H 2 O)), as well as some interaction between the two phases. The amorphous or very fine particular phase was also found in the floc. The substitution of Fe 3+ ions by Al 3+ ions in the solid surface has been observed, indicating an alternative removal mechanism of arsenic in these metal hydroxides and oxyhydroxides by providing larger surface area for arsenic adsorption via retarding the crystalline formation of iron oxides.

Sulfone-based electrolytes have been investigated as electrolytes for lithium-ion cells using high-voltage positive electrodes, such as LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 spinels, and Li 4 Ti 5 O 12 spinel as negative electrode. In the presence of imide salt (LiTFSI) and ethyl methyl sulfone or tetramethyl sulfone (TMS) electrolytes, the Li 4 Ti 5 O 12 /LiMn 2 O 4 cell exhibited a specific capacity of 80 mAh g À1 with an excellent capacity retention after 100 cycles. In a cell with high-voltage LiNi 0.5 Mn 1.5 O 4 positive electrode and 1 M LiPF 6 in TMS as electrolyte, the capacity reached 110 mAh g À1 at the C/12 rate. When TMS was blended with ethyl methyl carbonate, the Li 4 Ti 5 O 12 /LiNi 0.5 Mn 1.5 O 4 cell delivered an initial capacity of 80 mAh g À1 and cycled fairly well for 1000 cycles under 2C rate. The exceptional electrochemical stability of the sulfone electrolytes and their compatibility with the Li 4 Ti 5 O 12 safer and stable anode were the main reason behind the outstanding electrochemical performance observed with high-potential spinel cathode materials. These electrolytes could be promising alternative electrolytes for high-energy density battery applications such as plug-in hybrid and electric vehicles that require a long cycle life.

The electrochemical reduction of the Schiff base ligands N,N'-1,2-ethylenebis(salicylideneimine) and N,N'-1,2-phenylenebis (salicylideneimine) has been investigated in DMF by cyclic voltammetry, coulometry and controlled potentia1 electrolysis. The process involves a self-protonation mechanism whereby the two-electron reduction product, a cyclic derivative, is formed together with the conjugate base of the substrate, as a consequence of proton transfer from the substrate itself to the basic inte~ediates 0 1997 Elsevier Science Ltd.

Arsenic contamination is an enormous worldwide problem. A large number of people dwelling in Comarca Lagunera, situated in the central part of northern México, use well water with arsenic in excess of the water standard regulated by the Secretary of Environment and Natural Resources of México (SEMARNAT), to be suitable for human health. Individuals with lifetime exposure to arsenic develop the classic symptoms of arsenic poisoning. Among several options available for removal of arsenic from well water, electrocoagulation (EC) is a very promising electrochemical treatment technique that does not require the addition of chemicals or regeneration. First, this study will provide an introduction to the fundamental concepts of the EC method. In this study, powder X-ray diffraction, scanning electron microscopy, transmission Mössbauer spectroscopy and Fourier transform infrared spectroscopy were used to characterize the solid products formed at iron electrodes during the EC process. The results suggest that magnetite particles and amorphous iron oxyhydroxides present in the EC products remove arsenic(III) and arsenic(V) with an efficiency of more than 99% from groundwater in a field pilot scale study.

Objectives: Advances in surface electromyography (sEMG) techniques provide a clear indication that refinement of electrode location relative to innervation zones (IZ) is required in order to optimise the accuracy, relevance and repeatability of the sEMG signals. The aim of this study was to identify the IZ for the sternocleidomastoid and anterior scalene muscles to provide guidelines for electrode positioning for future clinical and research applications.

This paper presents the comparative results with respect to electrode configurations on the economic performance of treatment of textile wastewaters by electrocoagulation (EC) process. Aluminum and iron electrode materials were used as sacrificial electrode in parallel and serial connection modes. Various direct and indirect cost items including electrical, sacrificial electrodes, labor, sludge handling, maintenance and depreciation costs were considered in the calculation of the total cost per m 3 of wastewater taken from a textile plant with a capacity of 1000 m 3 per day. The results showed that monopolar-parallel mode (MP-P) was the most cost-effective for Fe and Al electrodes. These electrodes showed similar results in removal efficiency of COD and turbidity, but Fe electrode was preferred due to its low cost. pH 7 for Fe electrode and pH 5 for Al electrode were found suitable in terms of removal efficiency of COD and turbidity from textile wastewater. Meanwhile, 30 A m −2 of current density and 15 min of operating time were found to be sufficient for Fe and Al electrodes. Finally, a comparative study showed that EC was faster and more economic; consumed less material and produced less sludge, and pH of the medium was more stabilized as compared to chemical coagulation (CC) for percentage removal efficiency of COD and turbidity from textile wastewater. The treatment cost of EC at optimum conditions was 3.2 times cheaper than that of CC.

Objective: To analyze the functional connectivity patterns of the EEG slow-wave activity during the different sleep stages and Cyclic Alternating Pattern (CAP) conditions, using concepts derived from Graph Theory. Methods: We evaluated spatial patterns of EEG slow-wave synchronization between all possible pairs of electrodes (19) placed over the scalp of 10 sleeping healthy young normal subjects using two graph theoretical measures: the clustering coefficient (Cp) and the characteristic path length (Lp). The measures were obtained during the different sleep stages and CAP conditions from the real EEG connectivity networks and randomized control (surrogate) networks (Cp-s and Lp-s). Results: Cp and Cp/Cp-s increased significantly from wakefulness to sleep while Lp and Lp/Lp-s did not show changes. Cp/Cp-s was higher for A1 phases, compared to B phases of CAP. Conclusions: The network organization of the EEG slow-wave synchronization during sleep shows features characteristic of small-world networks (high Cp combined with low Lp); this type of organization is slightly but significantly more evident during the CAP A1 subtypes. Significance: Our results show feasibility of using graph theoretical measures to characterize the complexity of brain networks during sleep and might indicate sleep, and the A1 phases of CAP in particular, as a period during which slow-wave synchronization shows optimal network organization for information processing.

Objective: We investigated the ability of quantitative electroencephalography (QEEG) measures in sub-acute stroke to assist monitoring or prognostication of stroke evolution. QEEG indices and National Institutes of Health Stroke Scale (NIHSS) scores were compared. Methods: Ischaemic cortical stroke patients were studied. Resting, 62-channel EEG and NIHSS score were acquired at 49 ± 3 h postsymptom onset, and NIHSS administered at 30 ± 2 days post-stroke. Mean power was calculated for delta (1-4 Hz), theta (4.1-8 Hz), alpha (8.1-12.5 Hz) and beta (12.6-30 Hz) frequency bands, using a 62-channel electrode array and a 19-channel subset. Results: Thirteen patients (6 male, median age 66, range 54-86 years) were studied. Sub-acute delta:alpha power ratio (DAR; r = 0.91, P < 0.001), relative alpha power (r = À0.82, P < 0.01), and NIHSS score (r = 0.92, P < 0.001) each were significantly correlated with 30day NIHSS score. The former two significant correlations were upheld in 19-channel EEG data. QEEG measures involving theta or beta power were not significantly correlated with NIHSS scores. Conclusions: QEEG measures such as DAR demonstrate potential to augment bedside assessment of cerebral pathophysiology and prognostication of stroke evolution. A standard, 19-channel array seems adequate for these purposes. Future studies in larger samples should investigate the potential effects on these measures of sleep state and possible causes of artefacts. Significance: QEEG measures from a standard number of electrodes, if available rapidly and robust to potential artefacts, may inform future management of stroke patients.

In the present work, the synthesis and the spectroelectrochemical characterization of a novel iron compound derived of tetra-2-pyridyl-1,4pyrazine (TPPZ) with hexacyanoferrate species forming a very stable supramolecular complex in the presence of polypyrrole (PPY) matrix, is described. The hybrid material has shown excellent catalytic activity towards H 2 O 2 detection that makes it suitable for being used as redox mediator in a glucose biosensor. The hybrid FeTPPZFeCN/PPY film presents satisfactory detection limits and high sensitivity for H 2 O 2 in the presence of K + or Na + ions. For the glucose biosensor, a linear range up to 1.1 mmol l −1 of glucose was observed with no interferences. In this case, the sensitivities obtained were 7.88 and 5.90 A mmol −1 l cm −2 in phosphate buffer or NaCl solutions, respectively. The good sensitivity is related to the presence of a high-dimensional structure based on polypyridine type ligands providing an "electron antennae effect" facilitating electron tunneling between the protein and the electrode.

The bench scale of an electrocoagulation (EC) unit requires a detailed study discerning the effects of continuous variables such as pH, current density and operating time, and type variables such as electrode material and connection mode. This paper presents the results of the treatment of a textile wastewater by EC process. Two electrode materials, aluminum and iron, were connected in three modes namely, monopolarparallel (MP-P), monopolar-serial (MP-S), and bipolar-serial (BP-S). COD and turbidity removals were selected as performance criteria. For a high COD removal, acidic medium is preferable for both electrode materials. For a high turbidity removal, acidic medium is preferable for aluminum, and neutral medium for iron. High current density is favorable for both removals in the case of iron. In the aluminum case, the current density exhibits a pronounced effect on COD removal, depending strongly on the connection mode, but it has a negligible effect on the turbidity removal. MP-P with iron or MP-S with aluminum electrode are suitable configurations in regard with the overall process performance.

This paper describes a new method for manufacturing a nanostructured porous layer of a semiconductor material at room temperature. The porous layer is pressed on a conducting glass or plastic substrate for use in a dye-sensitized nanocrystalline solar cell. The method compresses the particle layer to form a mechanically stable, electrically conducting, porous nanostructured film. Overall, solar to electric conversion efficiencies of up to 5.2% at 0.1 sun using plastic substrates have been obtained.

Breaking the skin when applying scalp electroencephalographic (EEG) electrodes creates the risk of infection from blood-born pathogens such as HIV, Hepatitis-C, and Creutzfeldt-Jakob Disease. Modern engineering principles suggest that excellent EEG signals can be collected with high scalp impedance (≈ 40 kΩ) without scalp abrasion. The present study was designed to evaluate the effect of electrode-scalp impedance on EEG data quality.

This study was performed to investigate the variables that influence the removal efficiency of an acid dye, i. e., cotton blue (CB) (chemical name: aniline blue WS) dye, from aqueous solution by an electrocoagulation (EC) technique. Batch EC studies were performed using aluminum electrodes to evaluate the influences of various experimental parameters, i. e., initial pH (pH 0 ): 3 -11, electrolysis time (t): 0 -30 min, initial concentration (C 0 ): 100 -1000 mg/L, electrode gap (g): 0.5 -1.3 cm, number of electrodes (N): 4 -10, and applied voltage (V ap ): 7 -11 V, on the removal of CB dye. The optimum values of pH 0 , V ap and t for CB removal were found to be 6.0, 11 V and 15 min, respectively. The removal efficiency increased with decreasing values of C 0 and g. For a CB solution having C 0 = 100 mg/L, 97% removal efficiency was obtained at the optimized conditions. It was found that the EC sludge can be dried and thermally degraded. The bottom ash obtained after its combustion can be blended with cementitious mixtures. This approach for EC sludge disposal ensures energy recovery along with safe disposal of the EC sludge.

Objective: This study examined the effect of motivation as a possible psychological influencing variable on P300 amplitude and performance in a brain-computer interface (BCI) controlled by event-related potentials (ERP). Methods: Participants were instructed to copy spell a sentence by attending to cells of a randomly flashing 7 Ã 7 matrix. Motivation was manipulated by monetary reward. In two experimental groups participants received 25 (N = 11) or 50 (N = 11) Euro cent for each correctly selected character; the control group (N = 11) was not rewarded. BCI performance was defined as the overall percentage of correctly selected characters (correct response rate = CRR). Results: Participants performed at an average of 99%. At electrode location Cz the P300 amplitude was positively correlated to self-rated motivation. The P300 amplitude of the most motivated participants was significantly higher than that of the least motivated participants. Highly motivated participants were able to communicate correctly faster with the ERP-BCI than less motivated participants. Conclusions: Motivation modulates the P300 amplitude in an ERP-BCI. Significance: Motivation may contribute to variance in BCI performance and should be monitored in BCI settings.

The common sulphide mineral pyrrhotite (Fe (1− x) S) occurs in varying crystallographic forms with each type exhibiting subtly different physical and chemical properties. Accounts in the literature suggest that the processing behaviour of magnetic and non-magnetic ...

The charge storage mechanism of nanostructured hydrated manganese dioxide, as a supercapacitor electrode, was investigated with respect to the role of amount of hydrates on the electrolyte cations diffusion. The MnO 2 materials (␥-and layered types), prepared by a novel ultrasonic aided procedure. Thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the water content of the samples. The samples then were heat-treated in air for 2 h at 70, 100 and 150 • C to prepare different ␥and L-series of electrodes with various amounts of hydrates. To determine the role of the protonic conduction on the charge storage mechanism, the electrochemical properties of the electrodes were investigated in two different electrolyte pH values of 3.3 and 6.

Objective: To describe intracochlear insertion trauma caused by three perimodiolar cochlear implant electrodes. Study Design: Descriptive histological study of 15 human cadaver temporal bones. Methods: Fifteen cadaver temporal bones underwent surface preparation and were implanted with one of the following perimodiolar electrode arrays: Combi 40؉PM (MedEl Corporation), HiFocus II (Advanced Bionics Corporation), or Contour (Cochlear Corporation). A cryosectioning technique was used to study horizontal sections at 200-m intervals with the electrode in place. Image-enhanced videofluoroscopy and computer-assisted morphometrics were used to assess the mechanism of insertion trauma and to determine electrode position within the modiolus. Results: Histological examination revealed varying degrees of damage to the spiral ligament, basilar membrane, and osseous spiral lamina. Using a novel grading system for electrode trauma, there was no statistically significant difference among the three electrodes. A literature search of histological studies of a commonly used "standard" electrode showed damage equal to or greater than that seen in the current study. Conclusions: Insertion trauma caused by periomodiolar electrodes occurs to an acceptable degree. Refinement of electrodes based on mechanisms of trauma may be able to further reduce damage.

This paper represents the optimization of the electric discharge machining (EDM) of
Titanium alloy (Ti-6Al-4V) with a core electrode using grey relational analysis. Experimental
results confirm that the electrolytic copper electrode with central and eccentric through-holes
has the optimum performance for machining from various aspects. Three observed values,
material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra,) verify
this optimization of the machining technique. In addition, seven independent parameters are
chosen as variables in evaluating the Taguchi method and are categorized into two groups:
electrical parameters and non-electrical parameters. Moreover, analysis of the Taguchi
method reveals that the electrical group has a more significant effect than the non-electrical
group on the machining characteristics. Furthermore, either the pulse on duration or the peak
current most prominently affects the MRR, SR or EWR amongst all of the parameters,
whereas none of the non-electrical group has an equal affect. To overcome the limitations of
Taguchi methodology which can only optimize only one output parameter at a time “The
Grey Relational Analysis” has been done.
Key Words: Electro-discharge machining (EDM), Material removal rate (MRR); Electrode
wear rate; Surface roughness; High speed machining.