The example of conductive materials of carbon-based matrices are glassy carbon, graphite and nano-carbon or mixture of the element which have the electrical conductivity properties. The other material composed of insulator components group such as epoxy resin, silicone, polyurethane, metacrylate resin, Teflon and others. The insulator components are used to maintain the durability and resistance to electrical current toward the working medium (Alhadeff and Bojorge, 2011). Generally, biosensor used three-electrode system include working electode, auxillary electrode and reference electrode. Electrode which acts as auxillary platinum cathode undergoes reduction process where oxygen is reduced while Ag/AgCl works as reference electrode.
Cyclic voltammetry is used in this study, thus more detailed discussion is given below. 2.2 Theory and Principles of Cyclic Voltammetry The expression cyclic voltammetry simply specifies the relationship between the potential of an electrode and species (designated O and R) involved in the Redox (reduction/oxidation) reaction at that electrode. 2.2.1 Theory: The Nernst Equation, Mass Transfer and Fick’s Law: Oxidation or reduction of a species depends on the potential applied on the working electrode. Let us consider following reaction that can be adopted for FCA couple; aO + ne- bR (1) Where, O is reactant species which is being reduced to product R, and a and b are their respective reaction coefficients, the reaction quotient Q is defined as; Q = [R]b/ [O]a (2) Fe3+ +1e- Fe2+ (3) The reaction quotient in terms of FCA redox couple; Q = [Fe2+] b/ [Fe3+] a
1. Introduction Electrochemical impedance spectroscopy (EIS) is one of the oldest electroanalytical method which firstly proposed by the Randles in the middle and late 1940s. EIS has various advantages, among which some properties of this method such as non-destructive, sensitive and highly informative, distinguished it from other electrochemical methods. EIS technique can study the behavior of the electrode–electrolyte interfaces. Because of this fact that the surface properties of electrodes are a function of the electrolyte-electrode interface, this method can be used in the modern surface science and technology.
It is applicable to think about the consequences of each of these ways of operation. For all three ways, the behavior of the cell is controlled by an equation similar to Equation 22-20 E_cell=(E_cathode- E_anode )+[(η_cathode-η_anode )-IR] Where the equation in the box means, E_appl is the applied potential from an external source, E_c and E_a are the reversible thermodynamic potential associated with cathode and anode, η_cc and η_ck are the over voltages due to concentration polarization and kinetic polarization at the cathode, η_ac and η_ak are the over voltages due to concentration polarization and kinetic polarization at the anode, I is the current and R is the resistance. Take note that the four over voltages always carry a negative sign because they are potentials that must be overcome in order for charge to pass through the cell. Take note the in most application, the metal is deposited on a weighed platinum cathode, and the increase in mass is determined. Electrogravimetry without potential control of the working electrode, involved deposition of the desired metallic element upon a previously weighed cathode, followed by subsequent reweighing of the electrode plus deposit to obtain by difference the quantity of the
Choice of the materials has been made by considering the environment around the cation which would be substituted by incoming lanthanide ion (activator), phonon energy of the lattice and luminescent character of the host. Materials belonging to the molybdate and tungstate families have a long history of practical applications and have been the object of extensive research over the past century .The continuous interest in these compounds lies in their excellent stability and optical properties (broad absorption and emission band), which form the basis of their wide use as phosphors, laser materials, and scintillation detectors. The mechanochemically assisted SSM reaction route at room temperature is a fast and rapid method and by using this method, fine, chemically homogenous, pure and highly crystalline phase phosphor materials can be prepared in a very short period. Currently, It is the most widely used synthesis technique for production of micro/nanoparticles at industrial scale due to its cost-effectiveness and process versatility for controlled production of particles, especially with regular shape and fine size. To
¬¬¬¬¬¬Abstract Electrical circuits are described with mathematical expressions. Usually, it is possible to calculate the currents and voltages in a circuit by solving a set of equations, the calculations are required to design a safe circuit.and this is one reason why advanced mathematics is so important in the field of electrical engineering. The circuit equations can be determined using Ohm’s Law, which gives the relationship between voltage and current in a resistor (V=IR), and Kirchhoff’s Current and Voltage Laws, which govern the currents entering and exiting a circuit node and the sum of voltages around a circuit loop, respectively. Objective(s) The purpose of this experiment is to verify Ohm's Law using resistor in dc and ac circuits.
By accounting for material entering and leaving a system, mass flows can be identified which might have been unknown, or difficult to measure without this technique. Therefore, mass balances are used widely in engineering and environmental analyses. For example, mass balance theory is used to design unit processes such as chemical reactors, distillation columns, absorbers, heat exchangers, to analyze alternative processes to produce chemicals, as well as to model pollution dispersion and other physical processes or physical systems. Closely related and complementary analysis techniques include the population balance, energy balance and the somewhat more complex entropy balance. These techniques are required for thorough design and analysis of systems such as process plants, the refrigeration cycle etc.
Here we studied the bio fuel cells and bio batteries. The EFC are classified based on the type of electron transfer, MET and DET. In DET (direct electron transfer) of the bio-fuel cells electrons are directly transfer to the electrode from the enzymes. On the other hand in MET (mediator electron transfer) we use a mediator for transferring electron from the enzyme to the electrode.
III. Phase Shift Control In this method the voltage regulation is achieved by DSTATCOM. The error signal is obtained by comparing the Vrms voltage with the reference voltage and this error signal is fed to the PI controller. The PI controller process the Fig 2.Block diagram of phase shift control Difference between those two signals in order to obtain the phase angle which decides the necessary phase shift between output voltage of the VSC and the AC terminals . The proportional gain is playing important role in this controller.
In most cases these oxides are to be modified chemically or physically so as to get desired catalytic activity for a particular reaction. Oxides, because of their ability to take part in the exchange of electrons, protons or oxide ions, are used as catalysts in both redox and acid base catalysis, In metal oxides, coordinative unsaturation is principally responsible for the ability towards the adsorption and catalysis of various reactions. The exposed cations and anions of the metal oxide surfaces form acidic and basic sites as well as acid-base pairs. Besides this, the variablevalency of the cation results in the ability of the oxides to undergo oxidations and reductions. Semiconductor oxides such as TiO2, ZnO, WO3, SnO2, etc.