Solid oxide fuel cells (SOFC) are efficient and clean power generation devices. Lowtemperature
SOFC (LTSOFC) has been developed since high-temperature SOFC (HTSOFC) is not
feasible to be commercialized due to cost. Lowering the operation temperature reduces its substantial
performance resulting from cathode polarization resistance and overpotential of cathode. The
development of composite cathodes regarding mixed ionic-electronic conductor (MIEC) and ceriabased
materials for LTSOFC minimizes the problems significantly and leads to an increase in
electrocatalytic activity for the occurrence of oxygen reduction reaction (ORR). Lanthanum-based
materials such as lanthanum strontium cobalt ferrite (La0.6Sr0.4Co0.2Fe0.8O3-δ) have been discovered
recently, which offer great compatibility with ceria-based electrolyte to be applied as composite
cathode materials for LTSOFC. Cell performance at lower operating temperature can be maintained
and further improved by enhancing the ORR. This paper reviews recent development of various ceriabased
composite cathodes especially related to the ceria-carbonate composite electrolytes for
LTSOFC. The influence of the addition of metallic elements such as silver (Ag), platinum (Pt) and
palladium (Pd) towards the electrochemical properties and performance of LSCF composite cathodes
are also discussed.
Microbial electrochemical systems (MESs) are an attracting technology for the disposal of wastewater treatment and simultaneous energy production. In MESs, at the anode microorganisms through the catalytic activity generates electrons that can be converted into electricity or other valuable chemical compounds. Microorganisms those having ability to donate and accept electrons to and from anode and cathode electrodes, respectively are recognized as 'exoelectrogens'. In the MESs, it renders an important function for its performance. In the present mini-review, we have discussed the role of microbiome including pure culture, enriched culture and mixed culture in different BESs application. The effects of operational and biological factors on microbiome development have been discussed. Further discussion about the molecular techniques for the evaluation of microbial community analysis is addressed. In addition different electrochemical techniques for extracellular electron transfer (EET) mechanism of electroactive biofilms have been discussed. This review highlights the importance of microbiome in the development of MESs, effective operational factors for exo-electrogens activities as well their key challenges and future technological aspects are also briefly discussed.
Evidence of ossification was previously considered a relative contraindication to cochlear implantation. It was considered difficult or impossible to achieve safe electrode insertion because of bony obstruction. Either the electrodes or the inner ear structures could be damaged. Moreover, obstructed scala tympani could limit the number of electrodes that can be inserted. The efficacy of the electrical stimulation was also questioned, as a higher current would be needed on an ossified cochlea. Finally, the neural survival in ossified cochlea is unknown. This may complicate the surgical procedure and affect the long-term outcome. However, depending on the experience of the surgeon, cochlear implantation has been attempted even in grossly ossified cochlea. Here we illustrate that cochlear implantation is safe in labyrinthitis ossificans.
An experimental study of the field emission from nitrogen doped Diamond-Like-Carbon (DLC) thin films prepared by plasma Chemical Vapor Deposition (CVD) was carried out for the purpose of investigating the characteristic of field electron emission from the surface of nitrogen doped DLC thin film. Thin DLC film was deposited on silicon using the plasma CVD method, from a mixture of Methane (CH4), Helium (He) and Nitrogen (N2) at room temperature. Emission current was measured while high volume of voltage was applied between the cathode-anode diode structures. Barrier height was obtained by current density-electric field (J-E) characteristic in the relation of Fowler-Nordheim equation. The value of barrier height in range of 0.03eV to 0.06eV was obtained and considered as low barrier.
Researchers have developed and modified DNA biosensor techniques to provide a fast, simple and sensitive method for detection of human diseases, bacterial food contamination, forensic and environmental research. This study describes the physical characterization of screen-printed carbon electrodes using the scanning electron microscope.
Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. The use of boundary element analysis system (BEASY) has allowed cathodic protection (CP) interference to be assessed in terms of the normal current density, which is directly proportional to the corrosion rate. This paper was present the analysis of the galvanic corrosion between Aluminium and Carbon Steel in natural sea water. The result of experimental was validated with computer simulation like BEASY program. Finally, it can conclude that the BEASY software is a very helpful tool for
future planning before installing any structure, where it gives the possible CP interference on any nearby unprotected metallic structure.
CaCu3Ti4O12 (CCTO) has attracted a great attention for electronic devices miniaturization due to its
very high dielectric constant properties at a wide range of frequency and nearly constant over broad temperature range. The origins of the giant dielectric constant have been speculated from electrical heterogeneous of interior elements of the CCTO ceramics. Four origins were suggested contributed to the electrical heterogeneous. In this study heat treatment were done with the electrode contact in Argon gas environment and the electrical properties over very wide frequency of CCTO ceramics were investigated. Cylindrical CCTO pellets samples were prepared by solid state reaction method and single phase of XRD pattern was obtained after sintering processes. Electrical impedance responds were measured at frequency from 100 Hz to 1 GHz for the samples for untreated and heat treated at 200ºC, 250ºC, 300ºC, 350ºC and 400ºC of CCTO. Improvement to the dielectric constant can be seen for 350ºC and 400ºC samples and dielectric loss were improved for 200ºC and 300ºC samples for overall frequency. The variations were discussed based on oxygen deficiency content and resistivity of the elements inside of CCTO structure.
The corrosion behaviour of ternary aluminium alloy sacrificial anodes with small amount addition of tin as depassivating element in natural seawater was studied by means of conventional DC electrochemical measurements. Metallurgical microscope was employed in order to observe the changing of microstructure caused by tin present in ternary alloys. The relationship between microstructure and electrochemical results was examined and particular attention paid to the cause of the electrochemical efficiency of anode performance. The results indicate that the proper precipitates uniformly distributed of tin are influence on improving electrochemical performance of alumnium alloy anode.
Aluminium (Al) is a low cost, lightweight and corrosion resistant material, which corrodes when exposed to pitting agents. Palm olein exhibits characteristics, which indicate its suitability as a corrosion inhibitor. Tween 20, hexane and diethyl triamine were used as additives to Palm olein to form the inhibitor formulation POT2OHA. The inhibition efficiency (IE) and behaviour of the POT2OHA were determined using potentiodynamic polarization in which Al 6061 samples were immersed in a 1 M HC1 solution at 26, 50 and 70 °C in the presence of different POT2OHA concentrations: 0, 0.03, 0.07, 0.10, 0.13 and 0.17 M The IE increased with increasing POT2OHA concentration, but decreased with increasing temperature. The work presented indicates that POT2OHA is a mixed-type inhibitor capable of inhibiting both corrosive anodic and cathodic reactions. According to the Langmuir isotherm results POT2OHA adsorbs on the A16061 surface through semiphys iosorption and/or semi-chemisorption. The POT2OHA adsorption mechanism on Al 6061 takes through the protonation of micelles by the HC1 solution, whereby protonated micelles in the presence of chloride ions adsorb on both cathodic and anodic surface corrosion sites.
Herein, we report on the optimum condition for TiO2, titania nanotubes formation and the effect of annealing on the formation of anatase and rutile titania. Anodic oxidation was carried out in two electrodes bath consisting of 5wt% NH4F ions. The anode was a 0.1mm thick Ti foil and the cathode was Pt electrode. Anodisation was conducted at 20V. The anodised foils were subjected to morphological and structural characterizations. As-anodised foil was found to be amorphous or weakly crystalline. When the oxide was heat treated, x-ray diffraction analysis revealed the presence of (101) anatase at annealing temperature from 400-500°C. This indicates that the transformation occurs at this range of temperatures. Raman spectroscopy analysis showed the diminishing of anatase peaks for samples annealed at 500°C. At above 600°C, x-ray diffraction pattern shows a peak belonging to the rutile peak. Transformation from anatase to rutile is thought to occur at about 500°C with a more complete transformation at higher temperature. Annealing at higher than 600°C induces thickening of the nanotubes wall and at above 700°C, the nanotubes structure has completely disappeared.
Solid polymer electrolyte based on methyl cellulose (MC)-lithium triflate (LiCF3SO3) plasticised with ethylene carbonate (EC) was prepared using solution cast technique. The X-ray diffraction (XRD) studies proved that the amorphous nature of the electrolyte systems was increases due to the addition of salt and plasticiser. The improved surface morphology of plasticised polymer system ensures it has good electrode-electrolyte contact during performance testing. The polymer electrolyte was found to have high thermal stability indicating that the electrolyte can be used at higher temperature. The ionic conductivity increased up to 1.24 x 10-4 S cm-1 at optimum amount of EC plasticiser associated to the effect of plasticiser that initially leads to the formation of Li+-EC complex. Consequently, it reduces the fraction of polymer-Li+ complex which contributes to the increase of the segmental chain flexibility in the plasticized system. Temperature dependent studies indicate ionic conductivity increase due to the temperature increase and is in line with Arrhenius behaviour pattern. An activation energy of 0.26 eV at highest conductivity sample was obtained. The addition of plasticiser lowers the activation energy thus increasing the ion mobility of the system and contributing to ionic conductivity increment. The plasticization method is a promising means to dealing with the solid polymer electrolyte problem and producing electrolytes that meet the needs of electrochemical devices.
In the electrodeposition system, adding saccharin alters the properties of the metal deposits by changing the electrode kinetics of the deposited surface. In this study, nanocrystalline cobalt-iron (CoFe) coating was synthesised using the electrodeposition technique with different saccharin concentrations. The results obtained showed that the coating thickness increased while the grain size decreased from 51 nm to 40 nm when the saccharin concentration increased from 0 to 2 g/L. The nanocrystalline CoFe coating produced with 2 g/L of saccharin concentration resulted in the smallest particle size of 71.22 nm and the highest microhardness of 251.86 HV. From the salt spray test (24 and 48 hours) it was found that the use of saccharin at higher concentration of 2 g/L improves the corrosion resistance of the nanocrystalline CoFe coating significantly due to the change of surface morphology as well as the decrease in grain size.
In the last 10 years, the microbial fuel cell (MFC) has been extensively studied worldwide to extract energy from wastewater via electricity generation. More recently, a merged technique of embedding MFC into a constructed wetland (CW) has been developed and appears to be increasingly investigated. The driving force to integrate these two technologies lies in the fact that CWs naturally possess a redox gradient (depending on flow direction and wetland depth), which is required by MFCs as anaerobic anode and aerobic cathode chambers. No doubt, the integration of MFC with a CW will upgrade the CW to allow it to be used for wastewater treatment and, simultaneously, electricity generation, making CWs more sustainable and environmentally friendly. Currently, published work shows that India, China, Ireland, Spain, Germany and Malaysia are involved in the development of this technology although it is in its infant stage and many technical issues are faced on system configuration, operation and maximisation of electricity production. This paper aims to provide an updated review and analysis of the CW-MFC development. Focuses are placed on the experience gained so far from different researchers in the literature and further research directions and proposals are discussed in great detail.
Additive manufacturing also known as 3D printing is being utilised in electrochemistry to reproducibly develop complex geometries with conductive properties. In this study, we explored if the electrochemical behavior of 3D printed acrylonitrile butadiene styrene (ABS)/carbon black electrodes was influenced by printing direction. The electrodes were printed in both horizontal and vertical directions. The horizsontal direction resulted in a smooth surface (HPSS electrode) and a comparatively rougher surface (HPRS electrode) surface. Electrodes were characterized using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. For various redox couples, the vertical printed (VP) electrode showed enhanced current response when compared the two electrode surfaces generated by horizontal print direction. No differences in the capacitive response was observed, indicating that the conductive surface area of all types of electrodes were identical. The VP electrode had reduced charge transfer resistance and uncompensated solution resistance when compared to the HPSS and HPRS electrodes. Overall, electrodes printed in a vertical direction provide enhanced electrochemical performance and our study indicates that print orientation is a key factor that can be used to enhance sensor performance.
This study explored the influence of azo dye concentration, salinity (with and without aeration) and nitrate concentration on bioelectricity generation and treatment performance in the up-flow constructed wetland-microbial fuel cell (UFCW-MFC) system. The decolourisation efficiencies were up to 91% for 500 mg/L of Acid Red 18 (AR18). However, the power density declined with the increment in azo dye concentration. The results suggest that the combination of salinity and aeration at an optimum level improved the power performance. The highest power density achieved was 8.67 mW/m2. The increase of nitrate by 3-fold led to decrease in decolourisation and power density of the system. The findings revealed that the electron acceptors (AR18, nitrate and anode) competed at the anodic region for electrons and the electron transfer pathways would directly influence the treatment and power performance of UFCW-MFC. The planted UFCW-MFC significantly outweighed the plant-free control in power performance.
Researchers are increasingly showing interest in the application of a Butler matrix for fifth-generation (5G) base station antennas. However, the design of the Butler matrix is challenging at millimeter wave because of the very small wavelength. The literature has reported issues of high insertion losses and incorrect output phases at the output ports of the Butler matrix, which affects the radiation characteristics. To overcome these issues, the circuit elements of the Butler matrix such as the crossover, the quadrature hybrid and the phase shifter must be designed using highly accurate dimensions. This paper presents a low-loss and compact single-layer 8 × 8 Butler matrix operating at 28 GHz. The optimum design of each circuit element is also demonstrated in detail. The designed Butler matrix was fabricated to validate the simulated results. The measured results showed return losses of less than -10 dB at 28 GHz. The proposed Butler matrix achieved a low insertion loss and a low phase error of ± 2 dB and ± 10°, respectively. In sum, this work obtained a good agreement between the simulated and measured results.
Many techniques have been applied to fabricate nanostructures via top-down approach such as electron beam lithography. However, most of the techniques are very complicated and involves many process steps, high cost operation as well as the use of hazardous chemicals. Meanwhile, atomic force microscopy (AFM) lithography is a simple technique which is considered maskless and involves only an average cost and less complexity. In AFM lithography, the movement of a probe tip can be controlled to create nanoscale patterns on sample surface. For silicon nanowire (SiNW) fabrication, a conductive tip was operated in non-contact AFM mode to grow nanoscale oxide patterns on silicon-on-insulator (SOI) wafer surface based on local anodic oxidation (LAO) mechanism. The patterned structure was etched through two steps of wet etching processes. First, the TMAH was used as the etchant solution for Si removing. In the second step, diluted HF was used to remove oxide mask in order to produce a completed SiNW based devices. A SiNW based device which is formed by a nanowire channel, source and drain pads with lateral gate structures can be fabricated by well controlling the lithography process (applied tip voltage and writing speed) as well as the etching processes.
In this paper, fabrication and investigation of organic pressure sensor based on AlICIVT-VO 2(3j7)ICu composite is reported. The active layer of the composite was deposited by drop-casting of the blend CN'T-VO 2 (3fl) on a glass substrate (with prefabricated copper (Cu) electrode). The thin film of the blend consists of carbon nanotube CNT, (2.55 wt. %) and vanadium oxide (VO 2 (3fl)) micropowder, (3 wt. %) in benzol (1 mL). The thickness of the composite was in the range of 20-40 ,um. It was found that the fabricated sensor was sensitive to pressure and showed good repeatability. The decrease in resistance of the sensor was observed by increasing the external uniaxial pressure up to 50 kNm-2 . The experimentally obtained results were compared with the simulated results and showed reasonable agreement with each other.
We report here the fabrication of microgaps electrodes on amorphous silicon using low cost techniques such as vacuum deposition and conventional lithography. Amorphous silicon is a low cost material and has desirable properties for semiconductor applications. Microgap electrodes have important applications in power saving devices, electrochemical sensors and dielectric detections of biomolecules. Physical characterization by scanning electron microscopy (SEM) demonstrated such microgap electrodes could be produced with high reproducibility and precision. Preliminary electrical
characterizations showed such structures are able to maintain a good capacitance parameters and constant current supply over a wide ranging differences in voltages. They have also good efficiency of power consumption with high insulation properties.
In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50oC for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/cm2. From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde.