Electrode Pitch Research Articles

Influence of coking parameters on the quality of tar for electrode-pitch production

Changes in the raw materials employed and the coking conditions affect the quality of the tar byproducts used in the production of electrode pitch. The decline in tar quality associated with faster pyrolysis of the vapor-gas products within the coking chamber is discussed. The factors affecting the properties of the newly formed coal tar are analyzed, and the results are compared with theoretical concepts regarding the transformation of the primary products of pyrolysis in the coking chamber. Practical recommendations are developed regarding the production of higher-quality tar. Systematic monitoring of the volume and temperature of the free space within the chamber permits improvement in tar quality, despite increasing coking rates in the production of higher-quality coke. With a tar density of 1185–1190 kg/m3, the moisture content falls to 2.0–5.5%, and the ash content to 0.08–0.11%.

Maintaining the quality of electrode pitch produced at OAO EVRAZ ZSMK

The quality of the coal tar used in the production of electrode pitch at OAO EVRAZ ZSMK is analyzed. The factors that impair pitch quality are identified, and remedial measures are proposed. Promising refinements of tar processing are noted.

Pulse voltage operation of two-to-four-phase voltage-induction-type electrostatic motor

This paper analyzes pulse voltage operations of a two-to-four phase voltage-induction-type electrostatic motor (VITEM) to clarify the appropriate driving sequences. The paper also evaluates transient charge effects that can possibly enhance the thrust force. VITEM has been studied as a novel centimeter-sized electrostatic film motor whose power to the slider is supplied indirectly through its induction electrodes. Since a smooth synchronous driving was aimed in the past studies, high-frequency AC voltages have been used for the driving. This paper demonstrates that straightforward usage of simple pulse sequences cannot realize continuous stepping driving, and proposes several different sets of modified pulse sequences to realize continuous stepping driving using low-switching-rate pulse voltages. In the experiments, the motor showed continuous stepwise driving with a step width of about half of the electrode pitch. In addition, transient characteristics of charges on films were evaluated experimentally under the pulse driving condition, and contribution for thrust force enhancement was clarified.

Slurry removal from tar

We know that increasing the water content in coal tar above 4% and the ash content above 0.1% hinders its processing: soda consumption is increased; greater heating is required in dehydration; and it is impossible to comply with standards regarding the ash content in pitch coke and electrode pitch. Recently, the trend has been to introduce a centrifuge ahead of the final tar store in systems for conditioning coal tar.

Energy Spectrum Improvement with a CZT Strip Detector

Cadmium zinc telluride (CZT) has been shown to be suitable for use in high-resolution γ-ray energy spectroscopy and radiation imaging. A low-energy tail appears in the energy spectrum when the high-energy γ-ray energy spectrum is obtained with a CZT planar detector. This is due to the low charge transport in the crystal. In this study, a CZT detector with strip electrodes was fabricated to reduce the low-energy tail in the energy spectrum. CZT strip detectors with various electrode designs were fabricated, and their operation properties were determined and compared. The optimized detector had the following electrode design: an electrode pitch of 1.2 mm, an electrode width of 0.8 mm and a spacing between the electrodes of 0.4 mm. γ-ray energy spectra were measured for energies in the range of 60 – 660 keV. The low-energy tail in the spectrum was reduced significantly when the CZT strip detector was used.

Fabrication of sub-100 nm IDT SAW devices on insulating, semiconducting and conductive substrates

This work describes the electron-beam (e-beam) lithography process developed to manufacture nano interdigital transducers (IDTs) to be used in high frequency (GHz) surface acoustic wave (SAW) applications. The combination of electron-beam (e-beam) lithography and lift-off process is shown to be effective in fabricating well-defined IDT finger patterns with a line width below 100 nm with a good yield. Working with insulating piezoelectric substrates brings about e-beam deflection. It is also shown how a very thin organic anti-static layer works well in avoiding this charge accumulation during e-beam lithography on the resist layer. However, the use of this anti-static layer is not required with the insulating piezoelectric layer laying on a semiconducting substrate such as highly doped silicon. The effect of the e-beam dose on a number of different layers (of insulating, insulating on semiconducting, semiconducting, and conductive natures) is provided. Among other advantages, the use of reduced e-beam doses increases the manufacturing time. The principal aim of this work is to explain the interrelation among e-beam dose, substrate nature and IDT structure. An extensive study of the e-beam lithography of long IDT-fingers is provided, in a wide variety of electrode widths, electrode numbers and electrode pitches. It is worthy to highlight that this work shows the influence of the e-beam dose on five substrates of different conductive nature.

Numerical study of the microdroplet actuation switching frequency in digital microfluidic biochips

In this article, an electrohydrodynamic approach is used to study the microdroplet actuation in contemporary digital microfluidic biochips. The model is employed to analyze the microdroplet motion, and investigate the effects of the key parameters on the devices performance. The modeling results are compared to the experimental observations, and it is shown that the model provides an accurate representation of digital microfluidic transport. An extensive parametric variation is used to derive the maximum actuation switching frequency for ranges of the microdroplet size, gap spacing between the top and bottom plates and electrode pitch size. As a result, scalability of the devices is investigated, and it is shown that the microdroplet transfer rates change inversely with the system size, and microdroplet average velocity is nearly the same for different system scales. As a result of this study, an adjustable force-based actuation switching frequency implementation is proposed, and it is shown that faster microdroplet motion is obtained by in situ adjusting of the switching frequency. Finally, it has been observed that fastest microdroplet motion, despite similar studies conducted in the literature, is not achieved via actuating the next electrode as soon as the microdroplet touches it. Indeed, the switching frequency spectrum is dependent on the physical and geometrical properties of the system.

Comparative analysis of the planar capacitor and IDT piezoelectric thin-film micro-actuator models

A comparison of the analysis of similarly developed microactuators is presented. Accurate modeling and simulation techniques are vital for piezoelectrically actuated microactuators. Coupling analytical and numerical modeling techniques with variational design parameters, accurate performance predictions can be realized. Axi-symmetric two-dimensional and three-dimensional static deflection and harmonic models of a planar capacitor actuator are presented. Planar capacitor samples were modeled as unimorph diaphragms with sandwiched piezoelectric material. The harmonic frequencies were calculated numerically and compared well to predicted values and deformations. The finite element modeling reflects the impact of the d31 piezoelectric constant. Two-dimensional axi-symmetric models of circularly interdigitated piezoelectrically membranes are also presented. The models include the piezoelectric material and properties, the membrane materials and properties, and incorporates various design considerations of the model. These models also include the electro-mechanical coupling for piezoelectric actuation and highlight a novel approach to take advantage of the higher d33 piezoelectric coupling coefficient. Performance is evaluated for varying parameters such as electrode pitch, electrode width, and piezoelectric material thickness. The models also showed that several of the design parameters were naturally coupled. The static numerical models correlate well with the maximum static deflection of the experimental devices. Finally, this paper deals with the development of numerical harmonic models of piezoelectrically actuated planar capacitor and interdigitated diaphragms. The models were able to closely predict the first two harmonics, conservatively predict the third through sixth harmonics and predict the estimated values of center deflection using plate theory. Harmonic frequency and deflection simulations need further correlation by conducting extensive iterative harmonic simulations and experiments. The results, conclusions and potential improvements are discussed.

Numerical Modeling of a Circularly Interdigitated Piezoelectric Microactuator

Accurate modeling and simulation techniques are vital for actuated membranes. Using multiphysical modeling techniques, coupled with variation in design parameters, accurate performance predictions can be realized. A 2-D axis-symmetric model of a circularly interdigitated piezoelectrically membrane is presented. The model includes the piezoelectric material and properties, as well as the membrane materials and properties, and incorporates various design considerations. This model also includes the electromechanical coupling for piezoelectric actuation and highlights a novel approach to take advantage of the higher d33 piezoelectric coupling coefficient. Changes in parameters, including electrode pitch, electrode width, and piezoelectric material thickness, are evaluated.

Recent Progress in Neural Probes Using Silicon MEMS Technology

AbstractExtracellular recordings from the brain are the basis for the fundamental understanding of the complex interaction of electrical signals in neural information transfer. Going beyond wire electrodes and bundles of electrode wires such as tetrodes, multielectrode arrays based on silicon technologies are receiving growing attention, since they enable a pronounced increase in the number of recording sites per probe shaft. In this paper, recent innovations contributed by the authors to the development of probe arrays based on microelectromechanical system (MEMS) technologies within the EU‐funded research project NeuroProbes are described. The resulting structures include passive electrode arrays based on single‐shaft and four‐shaft probes comprising nine planar electrodes per shaft with lengths of up to 8 mm. Further, active probe arrays with complementary metal–oxide–semiconductor (CMOS) circuitry integrated on the probe shaft, enabling the arrangement of 188 electrodes in two columns along a 4‐mm‐long probe shaft with an electrode pitch of only 40 µm, are described. These active probes were developed for an electronic depth control. Further, the paper reports assembly technologies for combining the probe arrays with highly flexible ribbon cables. Applications of the probes in in vivo experiments are summarized. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Production of petro/coal tar pitch by joint distillation of coal tar and heavy pyrolytic oil

The properties of petro/coal tar pitch and distillate fractions obtained in the joint distillation of coal tar and heavy pyrolytic oil from ethylene production are described. The petro/coal tar pitch is particularly reactive in heat treatment and air-blowing. The petro/coal tar pitch may be used as less carcinogenic binder and impregnating electrode pitch.

Cochlear implant patients' speech understanding in background noise: effect of mismatch between electrode assigned frequencies and perceived pitch

To assess the electrode pitch function in a series of adults with postlingually implanted cochlear implants and with contralateral residual hearing, in order to investigate the correlation between the degree of frequency map mismatch and the subjects' speech understanding in quiet and noisy conditions. Case series. Seven postlingually deafened adults with cochlear implants, all with detectable contralateral residual hearing. Subjects' electrode pitch function was assessed by means of a pitch-matching test, in which they were asked to match an acoustic pitch (pure tones delivered to the non-implanted ear by an audiometer) to a perceived 'pitch' elicited by stimulation of the cochlear implant electrodes. A mismatch score was calculated for each subject. Speech recognition was tested using lists of sentences presented in quiet conditions and at +10, 0 and 5 dB HL signal-to-noise ratio levels (i.e. noise 10 dB HL lower than signal, noise as loud as signal and noise 5 dB HL higher than signal, respectively). Correlations were assessed using a linear regression model, with significance set at p < 0.05. All patients presented some degree of mismatch between the acoustic frequencies assigned to their implant electrodes and the pitch elicited by stimulation of the same electrode, with high between-individual variability. A significant correlation (p < 0.005) was found between mismatch and speech recognition scores at +10 and 0 dB HL signal-to-noise ratio levels (r2 = 0.91 and 0.89, respectively). The mismatch between frequencies allocated to electrodes and the pitch perceived on stimulation of the same electrodes could partially account for our subjects' difficulties with speech understanding in noisy conditions. We suggest that these subjects could benefit from mismatch correction, through a procedure allowing individualised reallocation of frequency bands to electrodes.

Switch-Matrix-Based High-Density Microelectrode Array in CMOS Technology

We report on a CMOS-based microelectrode array (MEA) featuring 11, 011 metal electrodes and 126 channels, each of which comprises recording and stimulation electronics, for extracellular bidirectional communication with electrogenic cells, such as neurons or cardiomyocytes. The important features include: (i) high spatial resolution at (sub)cellular level with 3150 electrodes per mm2 (electrode diameter 7 ?m, electrode pitch 18 ?m); (ii) a reconflgurable routing of the recording sites to the 126 channels; and (iii) low noise levels.

Microstructure of electrode pitch at OAO Zaporozhkoks

Analysis of literature data (including ASTM standards) shows that the only existing method that permits the identification of meso phase in pitch is optical microscopy. Even in special conditions conducive to meso-phase development, its formation in the pitch considered is found to be extremely slow.

A re-evaluation of the relation between physiological channel interaction and electrode pitch ranking in cochlear implants

Spatial excitation patterns in cochlear implant users can be measured with the electrically evoked compound action potential (ECAP). This study examined whether the relative separation of ECAP excitation patterns for two electrodes was correlated with the ability to discriminate those electrodes on the basis of pitch. Significant correlations were found for nine of the ten subjects. Electrodes with significant relative overlap of ECAP spatial excitation patterns were generally more difficult to distinguish on the basis of pitch. Pitch-ranking ability and overlap of ECAP patterns were both affected by the relative separation between electrodes in each pair. With increased separation between electrodes, pitch ranking improved significantly, and ECAP spatial excitation patterns showed significantly less overlap.

Novel Impact of Wet Dosages of NMP in Extraction for Production of High BMCI Carbon Black Feedstocks

In separation sciences, “Solvent Extraction” is one of the most important unit operations, a very widely used process, next only to distillation. In the petroleum refining industry, solvent extraction is commonly widely applied to produce a number of specialty products such as BTX, lube base oils, waxes, etc. There are many solvents used in various separation processes, like sulfolane, phenol, furfural, ketones, and N-methyl pyrollidone (NMP). NMP in particular is an environmentally benign, new generation solvent, which can be tailored for specific separations by using it in conjunction with small doses of water. In recent years, researchers are re-looking at the separation processes and their modifications to exploit these for producing high-value industrial products from low-value refinery streams. The present study deals with the production of high-quality carbon black feedstocks (CBFS) from clarified oils. The study shows the beneficial effect of using NMP in combination with different dosages of water as extraction solvent to extract low-value clarified oil, a cracked material from the FCC unit of an operating Indian refinery. In the present study, water ranging from 0.3 wt% to 10 wt% was used with NMP to produce aromatic extract of BMCI (Bureau of Mines Correlation Index) up to 146 through liquid-liquid equilibrium and mass transfer studies on clarified oil (CLO). The effect of solvent-to-feed ratio at constant temperature on solvent extraction was also studied. The addition of water in NMP alters the “selectivity” of solvent, which can be exploited for producing aromatic extracts of a wide range of BMCI for different end-use applications. The major users of such high BMCI extracts are carbon black and electrode pitch manufacturers. Regression analysis was also done to develop correlations between water percentage in NMP and targeted BMCI of aromatic extract. Presently, CLO is blended with fuel oil and sold as a very low value product in refinery. Since the demand of CBFS is increasing continuously and current short-fall in India is met through imports from China, Korea, and Japan, it is desirable that such studies are undertaken and will lead to production of high-value CBFS from low-value refinery streams through separation processes.

Miniature Surface Acoustic Wave Duplexer Using SiO2/Al/LiNbO3 Structure for Wide-Band Code-Division Multiple-Access System

In this paper, we describe the development of a miniature surface acoustic wave (SAW) duplexer for Band I in the standard of the Third-Generation Partnership Project (3GPP) at a 2 GHz band. We employed a shear-horizontal SAW on a SiO2 overlay/thick Al electrode/5°YX-LiNbO3 structure, which offers a high electromechanical coupling coefficient (K2) as well as a small temperature coefficient of frequency (TCF). This feature is crucial for the realization of a wide duplex gap between the transmitting and receiving bands in the Band I specification. We investigated experimentally that the spurious response caused by the Rayleigh-mode could effectively be suppressed by controlling the cross-sectional shape of a SiO2 overlay on interdigital transducer (IDT) electrodes. In addition, the result also showed how this spurious response depends on IDT design parameters, i.e., electrode pitch and metallization ratio. The developed SAW duplexer was installed in a 2.5×2.0 mm2 package, and exhibited a low insertion loss, a high out-of-band rejection and a small TCF.

Research of polymeric additive influence of organic composition on thermochemical conversion of carbon masses

Influence of polymeric addition is explored on properties of carbon the masses of itself calcinating electrodes in the process of their carbonation. It is exposed that polymeric addition intensifies co-operation of carbon filler with an electrode pitch – connective, that is high-quality represented on descriptions thermographic of laboratory masses. The mechanism of co-operation of components of carbon mass is formulated with a modifier.

Controlling the quality of electrode pitch from coal tar by complex formation and polycondensation

Controlling the quality of electrode pitch from coal tar by complex formation and polycondensation

Neuro-Technical Interfaces Based on Biocompatible Polymeric Substrates

AbstractMultielectrode arrays create the interfaces between nerves and technical systems in neuroprosthetic devices. MEMS (microelectromechanical systems) technologies offer opportunities to develop high density arrays with large numbers of electrodes and smallest dimensions of electrode site area and pitch. Polymers are promising candidates for flexible substrates of these electrode arrays to meet the requirements of structural biocompatibility. In addition, these substrates must be biostable and should be non-toxic. From an engineering point of view, material processing should be feasible with standard MEMS process technology. Fail-safe integration of electronic circuitry, encapsulation of the systems with substrate-integrated electrodes and connection to cables and connectors is of great importance for reliable (micro-) implants.A comprehensive overview of the application of polymers like silicone rubber, polyimide, and parylene C as substrate, insulation and encapsulation material for multielectrode arrays will be given. Assembling techniques for system integration and encapsulation concepts will be discussed with a special attention on the adhesion properties between substrate, interconnects and insulation and possible failure mechanisms. Application scenarios include peripheral nerve interfaces like cuff and sieve electrodes as well as multielectrode arrays for retinal vision prostheses and shaft and grid arrays for the central nervous system interfaces.