Excessively addition of coagulants can be avoided by using EC, due to the generation of the coagulants by electro oxidation of a sacrificial anode. EC has easy operation and simple equipment. The most common electrode materials used for EC are aluminum and iron. They are readily available, economical, very effective. When aluminum is used as electrode material, the reactions
In order to utilize casein, bacteria cells secrete proteolytic exoenzymes (amylases, proteases, pectinases, lipases, xylanases and cellulases) outside of the cell that hydrolyze the protein to amino acids. The amino acids can then be used by cells after crossing the cell membrane via transport proteins . Starch hydrolysis test is used to differentiate bacteria based on their ability to hydrolyze starch with the enzyme α-amylase or oligo-l, 6-glucosidase. These enzymes hydrolyze starch by breaking the glycosidic linkages between the sugar subunits. It aids in the differentiation of species from the genera Corynebacterium, Clostridium, Bacillus, Bacteroides, Fusobacterium and members of Enterococcus .
2.2. Apparatus Spectroelectrochemical experiments were carried out on Perkin-Elmer Lambda 25 UV/VIS spectrometer (made in USA) and CHI620B (made in China) with homemade long optical path length thin layer cell (LOPTLC, thickness of the thin layer is 0.020 cm) . A graphite carbon slice served as working electrode, a platinum wire as auxiliary electrode and a Ag/AgCl (KCl saturated) as reference electrode. All potentials are reported with respect with this reference electrode. Graphite carbon electrode was polished to a mirror-like surface with 1.0, 0.3 and 0.05 micron α-alumina powder in sequence and washed in supersonic for one minute before use.
In addition, all insulators become electrically conductive when a sufficiently large voltage is applied that the electric field tears electrons away from the atoms. This is known as the breakdown voltage of an insulator. Some materials such as glass, paper and Teflon, which have high resistivity, are very good electrical insulators. A much larger class of materials, even though they may have lower bulk resistivity, are still good enough to prevent major current from flowing at normally used voltages, and thus are employed as insulation for electrical wiring and cables. Examples include rubber-like polymers and the majority
They have a relatively high level of hydrophilicity. Conversely, cationic surfactants such as cetyltrimethyl ammonium bromide (CTAB) release a positive charge in an aqueous solution. On the other hand, in alkali pH, amphoteric surfactants act as anionic while in acid pH, it act as cationic. Non-ionic surfactants such as partially hydrolyzed PVA (polyvinyl alcohol) have no charge (Li et al, 2008). Among four types of surfactants, partially hydrolyzed PVA is most frequent used because it gives the smallest microsheres (Jeffrey et al, 1991).
DIGITAL ASSIGNEMENT -2 INTRODUCTION • Fibre reinforced plastics also known as the fibre reinforced polymer is a composite material made of polymer matrix reinforced with fibre. • Has two important components Fibre and Matrix. • Classified as composite plastics ,i.e. made out of bonding of materials with two different material property derived to give a certain property of the material • The fibres usually consists of glass, carbon, aramid and basalt….whereas paper wood or asbestos the material rarely used in the form of fibre. • The polymer or matrix is generally an epoxy, vinyl ester or polyester thermosetting plastic…even phenol thermal raisins are also used for the fibre matrix.
As it is used in extreme environments with elevated temperature and pressure, it is prone to oxidation. To inhibit oxidation process, matrix modification with silicon, zirconium or by multilayer oxidation protection coatings consisting of silicon carbide is done. C/C composites comprise of non-homogeneous structures like fibres, matrix and pores, and all of them combine to give a diversity of microstructures and owing to its complexity; it is difficult to predict the thermal carrying capacity (Manocha Lalit M., 2003). Other drawbacks are inhomogeneity, insufficient stability of friction coefficient cause due to humidity and high-cost of
Graphite occurs as layered planar structures and each layer carbon atoms are arranged in a hexagonal lattices. Single walled carbon nanotube is obtained on rolling up a single sheet of graphite called the graphene. CNTs are cylindrically arranged carbon molecules which have exceptional physical and thermal capabilities. The electrical properties of the Carbon nanotube is determined based on the type of rolling, the diameter and a few other factors. The two predominant type of rolled structures of a nanotubes are Zig-Zag and Arm Chair.
The controlled variable in a potentiostat is the cell potential and the measured variable is the cell current. Instrumentation Working electrode is the electrode where the potential is controlled and where the current is measured. For many physical electrochemistry experiments, the working electrode is an “inert” material such gold, platinum or glassy carbon. In these cases, the working electrode serves as a surface on which the electrochemical reaction takes place. Reference electrode is used to measure the working electrode potential.
They are synthesized by the reaction of a polyester polyol, or polyether polyol, with an aromatic or aliphatic isocyanine. The reagents often used for classroom demonstrations are polyester polyols and polyfunctional isocyanates. 2.1.3 Filler materials These are the materials most often added to polymers to improve tensile and compressive strengths, abrasion resistance, toughness, dimensional and thermal stability and other properties. Materials used as particulate fillers include wood flour (finely powdered saw dust), silica flour and sand, graphite, clay, talc, limestone. 2.2 Reinforcement 2.2.1 Woven mat This is a bi-directional reinforcement, obtained by weaving or textile operations using strands running in both directions warp (longitudinal) and fill (transverse) and fibres remain parallel to each other.