The hardcoat anodising process was done by using different concentration of H2SO4 from 0% to 20%. The 90 volt of anodising process was applied by using Al foil as cathode materials. The surface changes on PM Al-Mg resulted by hardcoat anodising was characterised by XRD measured. Surface hardness was measured by Micro-Vickers hardness machine. The experiment found different XRD pattern between anodised PM Al-Mg samples. The study was found by that the optimum value for H2SO4 concentration was 15 % H2SO4 and result 26 μm thickness, 5.07% of mass changes and HVN 105.4 hardness. The hardcoat anodising was affected to the XRD pattern for PM Al-Mg.
In the study, a relationship was establishment between electrical resistivity by using electrical resistivity imaging (ERI) technique with hydraulic conductivity. By using Schlumberger array configuration, 2D electrical resistivity image was produced by using ABEM SAS 4000 with eighty-one (81) electrodes (Loke, 2004) . By using regression equation, hydraulic conductivity was calculated from electrical resistivity and this result was compared with the hydraulic conductivity obtained from pumping tests (Butler, 2005). This data suggested that electrical resistivity survey can be used as preliminary tool to assess any subsurface zone with non- invasive nondestructive for soil, reducing time and cost.
The electrooxidation of propionaldehyde and butyraldehyde on a gold electrode was studied by cyclic voltammetry in alkaline media. Electrooxidation of both aldehydes showed the appearance of two anodic peaks. Another oxidation peak on a newly generated electrode surface was observed after the corresponding reduction peak for both aldehydes.
The electrical characteristics of a filamentary dielectric barrier discharge (DBD) are studied experimentally and numerically. The DBD system which has parallel plate electrodes geometry is powered by a 50 Hz power supply and operated at atmospheric air. A dynamic electric circuit model considering the discharge region and the non-discharge region being connected by a surface resistance is proposed. Simulation using this model is shown to fit the experimentally measured QV diagram satisfactorily. The effects of the air gap distance and the dielectric surface on the discharge behavior are then investigated. It is found that the surface resistivity of the dielectric is one of the important parameters governing the discharge behavior.
Recent studies have demonstrated the effectiveness of switching bipolar radiofrequency ablation (bRFA) in treating liver cancer. Nevertheless, the clinical use of the treatment remains less common than conventional monopolar RFA - likely due to the lack of understanding of how the tissues respond thermally to the switching effect. The problem is exacerbated by the numerous possible switching combinations when bRFA is performed using bipolar needles, thus making theoretical deduction and experimental studies difficult. This article addresses this issue via computational modelling by examining if significant variation in the treatment outcome exists amongst six different electrode configurations defined by the X-, C-, U-, N-, Z- and O-models. Results indicated that the tissue thermal and thermal damage responses varied depending on the electrode configuration and the operating conditions (input voltage and ablation duration). For a spherical tumour, 30 mm in diameter, complete ablation could not be attained in all configurations with 70 V input voltage and 5 minutes ablation duration. Increasing the input voltage to 90 V enlarged the coagulation zone in the X-model only. With the other configurations, extending the ablation duration to 10 minutes was found to be the better at enlarging the coagulation zone.
Wearable electronics and sensors are increasingly popular for personal health monitoring, including smart shirts containing electrocardiography (ECG) electrodes. Optimal electrode performance requires careful selection of the electrode position. On top of the electrophysiological aspects, practical aspects must be considered due to the dynamic recording environment. We propose a new method to obtain optimal electrode placement by considering multiple dimensions. The electrophysiological aspects were represented by P-, R-, and T-peak of ECG waveform, while the shirt-skin gap, shirt movement, and regional sweat rate represented the practical aspects. This study employed a secondary data set and simulations for the electrophysiological and practical aspects, respectively. Typically, there is no ideal solution that maximizes satisfaction degrees of multiple electrophysiological and practical aspects simultaneously; a compromise is the most appropriate approach. Instead of combining both aspects-which are independent of each other-into a single-objective optimization, we used multi-objective optimization to obtain a Pareto set, which contains predominant solutions. These solutions may facilitate the decision-makers to decide the preferred electrode locations based on application-specific criteria. Our proposed approach may aid manufacturers in making decisions regarding the placement of electrodes within smart shirts.
This review is variously a presentation, reflection, synthesis and report with reference to more recent developments of an article - in a journal which has ceased publication - entitled "Some Electrode Theorems with Experimental Corroboration, Inclusive of the Ag/AgCl System" Internet Journal of Chemistry, (http://www.ijc.com), Special Issues: Vol. 2 Article 24 (1999). The results from new lemmas relating charge densities and capacitance in a metallic electrode in equilibrium with an ionic solution are used to explain the data and observed effects due to Esin, Markov, Grahame, Lang and Kohn. Size effects that vary the measured e.m.f. of electrodes due to changes in the electronic chemical potential are demonstrated in experiment and theory implying the need for standardization of electrodes with respect to geometry and size. The widely used Stern modification of the Gouy-Chapman theory is shown to be mostly inapplicable for many of the problems where it is employed. Practical consequences of the current development include the possibility of determining the elusive single-ion activity coefficients of solution ions directly from the expression given by a simplified capacitance theorem, the potential of zero charge and the determination of single ion concentrations of active species in the electrode reactions from cell e.m.f. measurements.
Hematite (α-Fe2O3) nanoparticles were synthesized by the solid transformation of ferrous hydroxide and ferrihydrite in hydrothermal condition. The as-prepared α-Fe2O3 nanoparticles were characterized by UV-vis, PL, XRD, Raman, TEM, AFM, FESEM, and EDX analysis. The experimental results indicated the formation of uniform hematite nanoparticles with an average size of 45 nm and perfect crystallinity. The electrochemical behavior of a GC/α-Fe2O3 electrode was studied using CV and EIS techniques with an electrochemical probe, [Fe(CN)6](3-/4-) redox couple. The electrocatalytic activity was investigated toward DA oxidation in a phosphate buffer solution (pH 6.8) by varying different experimental parameters. The chronoamperometric study showed a linear response in the range of 0-2 μM with LoD of 1.6 μM for DA. Square wave voltammetry showed a linear response in the range of 0-35 μM with LoD of 236 nM for DA.
The subject of the submitted work is the proposal of electrodes for the continual measurement of the glucose concentration for the purpose of specifying further hemodynamic parameters. The proposal includes the design of the electronic measuring system, the construction of the electrodes themselves and the functionality of the entire system, verified experimentally using various electrode materials. The proposed circuit works on the basis of micro-ammeter measuring the size of the flowing electric current and the electrochemical measurement method is used for specifying the glucose concentration. The electrode system is comprised of two electrodes embedded in a silicon tube. The solution consists of the measurement with three types of materials, which are verified by using three solutions with a precisely given concentration of glucose in the form of a mixed solution and enzyme glucose oxidase. For the testing of the proposed circuit and the selection of a suitable material, the testing did not take place on measurements in whole blood. For the construction of the electrodes, the three most frequently used materials for the construction of electrodes used in clinical practice for sensing biopotentials, specifically the materials Ag/AgCl, Cu and Au, were used. The performed experiments showed that the material Ag/AgCl, which had the greatest sensitivity for the measurement even without the enzyme, was the most suitable material for the electrode. This conclusion is supported by the performed statistical analysis. On the basis of the testing, we can come to the conclusion that even if the Ag/AgCl electrode appears to be the most suitable, showing high stability, gold-plated electrodes showed stability throughout the measurement similarly to Ag/AgCl electrodes, but did not achieve the same qualities in sensitivity and readability of the measured results.
This paper presents the design of a non-intrusive system to measure ultra-low water content in crude oil. The system is based on a capacitance to phase angle conversion method. Water content is measured with a capacitance sensor comprising two semi-cylindrical electrodes mounted on the outer side of a glass tube. The presence of water induces a capacitance change that in turn converts into a phase angle, with respect to a main oscillator. A differential sensing technique is adopted not only to ensure high immunity against temperature variation and background noise, but also to eliminate phase jitter and amplitude variation of the main oscillator that could destabilize the output. The complete capacitive sensing system was implemented in hardware and experiment results using crude oil samples demonstrated that a resolution of ± 50 ppm of water content in crude oil was achieved by the proposed design.
In this study, porous silicon (PSi) was prepared and tested as an extended gate field-effect transistor (EGFET) for pH sensing. The prepared PSi has pore sizes in the range of 500 to 750 nm with a depth of approximately 42 µm. The results of testing PSi for hydrogen ion sensing in different pH buffer solutions reveal that the PSi has a sensitivity value of 66 mV/pH that is considered a super Nernstian value. The sensor considers stability to be in the pH range of 2 to 12. The hysteresis values of the prepared PSi sensor were approximately 8.2 and 10.5 mV in the low and high pH loop, respectively. The result of this study reveals a promising application of PSi in the field for detecting hydrogen ions in different solutions.
The construction of an electrical pain stimulator was described.
The parameters of pulse width and frequency on the quality of
pain stimulation was determined. The best design and construction
of the electrode for the stimulator was produced.
Two different supercapacitor configurations were fabricated using coconut shell-based activated
carbon. Results for cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge measurements are presented and discussed for both configurations. The results show that coconut shell-based activated carbon is viable economical alternative electrode material to expensive activated carbon (AC) and carbon nano tubes (CNT). Meanwhile, the calculations from the charge-discharge characteristics show that the disk-shape supercapacitor, with 10% polyvinylidene fluoride binder (PVdF), has the highest specific capacitance (70F/g). Thus, the testing shows that the flat-laminated super-capacitor with 10% binder (PVdF) has the lowest (10.1ohms). Sources of high equivalent series resistance (ESR) are proposed and methods of reducing it are also discussed in this paper.
Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image
formation and as well as scattered radiation. But there is paucity in the study related to heel effect.
This study is for mapping and profiling the dose on the surface of water phantom by using mobile
C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to at least
about 57% from anode to cathode bound of the irradiated area. This result and information can be
used as a guide to manipulate this phenomenon for better image quality and radiation safety for
this specific and dedicated fluoroscopy unit.
The bioanode is important for a microbial electrolysis cell (MEC) and its robustness to maintain its catalytic activity affects the performance of the whole system. Bioanodes enriched at a potential of +0.2V (vs. standard hydrogen electrode) were able to sustain their oxidation activity when the anode potential was varied from -0.3 up to +1.0V. Chronoamperometric test revealed that the bioanode produced peak current density of 0.36A/m(2) and 0.37A/m(2) at applied potential 0 and +0.6V, respectively. Meanwhile hydrogen production at the biocathode was proportional to the applied potential, in the range from -0.5 to -1.0V. The highest production rate was 7.4L H2/(m(2) cathode area)/day at -1.0V cathode potential. A limited current output at the bioanode could halt the biocathode capability to generate hydrogen. Therefore maximum applied potential that can be applied to the biocathode was calculated as -0.84V without overloading the bioanode.
Digital mammography has been progressively introduced in screening centers and the concern is to achieve an image of diagnostic value which would be able to detect early changes in the breast tissue. The aim of this study was to evaluate the image quality of mammograms using quantitative and qualitative methods of two FFDM systems with variations in breast thickness and anode/filter combination. This study was done from January to April 2008 with two FFDM systems; Siemens Mammomat NovationDR at Diagnostic Imaging Department, Hospital Kuala Lumpur and Hologic Lorad Selenia at Breast Clinic, National Cancer Society. A CIRS012A tissue equivalent breast phantom (4, 5 and 6 cm) thickness was used to obtain images in the craniocaudal plane with 26-32 kVp and a combination of molybdenum/molybdenum (Mo/Mo) and molybdenum/rhodium (Mo/Rh) anode/filter. For the qualitative evaluation, two independent radiologist with a minimum of five years experience was used to score the images. Wilcoxon Sign Rank Test showed that there are no significant differences (p > 0.05) in image quality between both the FFDM systems. Kappa analysis had a poor agreement between the scores given by the two radiologists. The quantitative analysis using Mann-Whitney test showed that there are significant differences (p < 0.05) between the SNR values of both FFDM systems. Although the qualitative evaluation was similar, the study showed that Lorad Selenia had a significantly superior SNR value, hence would be a better tool to detect early changes in the breast tissue. This study also demonstrated that a lower kVp is more suitable with molybdenum filter and as the breast thickness is increased rhodium filter with higher kVp displayed better quality images.
Surface free energies have been evaluated from Young’s moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ~1.47%Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≈ 0.08mA/cm 2 , current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surface free energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum.
A preliminary study was carried out to fabricate a three electrode system based on electrochemical sensoring. The cyclic voltammetry (CV) technique was chosen to select the type of metal suitable for evaporation and to compare the results produced from the fabricated gold electrode with the conventional macro-electrode system. The methodology and apparatus used involved low cost apparatus and methodology such as soft lithography, wet-etching, thermal evaporation, direct current sputtering, polymethylmethacrylate moulding and polydimethylsiloxane coating. The experiment was conducted at a fixed scan rate of 100 mV/s by using 0.01 M K3Fe(CN)6 in 0.1M KCl and well known method using Randles-Sevcik equation, peak current ratio and voltage separation was used to analyze the characterization on the fabricated sensors. Electrodes of 6.5 mm2 and 0.26 mm2 were fabricated to prove the adsorption effect of the reactant and the influence of the electrode area on the value of the peak current. CV analysis proved that the fabricated sensor was reliable for a range of 24 h at 25ºC room temperature.
Affordable and greener materials were extensively studied in electrode fabrication for Liion
based batteries but less interest was shown to proton battery. Hence, in this work,
a methodology on preparing a natural based binder for proton battery was reported. 2-
Hydroxyethyl Cellulose (2HEC) was chosen to replace PVDF commercial binder in electrode
for ZnSO4|MnO2 proton battery configuration. SEM image shows good surface formation
for both anode and cathode with good porous structure. OCV result shows that the cell
improved the stable voltage of reference cell of 0.7 V to 0.9 V after 24 hours. The first
discharge of the cell took 6 hours and 49 minutes at 0.005mA and shows good potential for
The aim of this work was to evaluate the comparative performance of hybrid metal oxide nanorods i.e. MnCo2O4 nanorods (MCON) and single metal oxide nanorods i.e. Co3O4 nanorods (CON) as oxygen reduction catalyst in microbial fuel cells (MFC). Compared to the single metal oxide, the hybrid MCON exhibited a higher BET surface area and provided additional positively charged ions, i.e., Co2+/Co3+ and Mn3+/Mn4+ on its surfaces, which increased the electro-conductivity of the cathode and improved the oxygen reduction kinetics significantly, achieved an io of 6.01 A/m2 that was 12.4% higher than CON. Moreover, the porous architecture of MCON facilitated the diffusion of electrolyte, reactants and electrons during the oxygen reduction, suggested by lower diffusion (Rd), activation (Ract) and ohmic resistance (Rohm) values. This enhanced oxygen reduction by MCON boosted the power generation in MFC, achieving a maximum power density of 587 mW/m2 that was ∼29% higher than CON.