Introduction Log-periodic dipole antenna array have advantage of self-similar structure,its electrical properties iterate periodically with logarithm of frequency.high-performance UWB antennas require impedance matching ,efficiency, low signal distortion within thespecified frequency bands1-3. The term notch is define here as the specific eatching that make change in radiation, directivity and efficiancy of antenna4. There are many existing wireless communications systems, which are …

Introduction We live in energy conscious era. In the community of electrical engineering energy consciousness has manifested itself in an increasing focus on low power circuits. Low power circuit implies low current or low voltage. They are more susceptible to the effect of noise. The fundamental physical concepts behind noise are simple. The myriad of random events that happen in …

Introduction Smart antennas are antennas arrays that are combined with signals processing in space and real time. Such antennas have their special need in cellular and mobile communication systems. The smart antennas have the properties of increasing the spectrum efficiency, channel capacity and coverage range. They have ability to provide certain channel in certain direction. They are able to reduce …

Introduction Composite electrolyte systems are the new class of fast ion conductors or super ionic solids. Super ionic are solids which contains high degree of ionic conductivity and low degree of electronic conductivity. Solid polymer electrolyte (SPE) membrane is emerging as candidates to be used as electrolyte membranes in high energy applications1 viz. solid state batteries, memory devices, chemical sensors, …

Introduction Nitrogen-containing ligands such as Schiff bases and their metal complexes played an important role in the development of coordination chemistry resulting in an enormous number of publications, ranging from pure synthetic work to physicochemical1 and biochemically relevant studies of metal complexes2-6 and found wide range of applications. The development of the field of bioinorganic chemistry has increased the interest …

Introduction Hot melt adhesives (HMA) are solid adhesives that are heated to a molten liquid statefor application to substrates and then cooled, quickly setting up the bond.1 The hot melt systems must achieve a relatively low viscosity when in the molten state to achieve proper wetting of the substrates. However, they must not cool too rapidly as they will not get …

Introduction Increasing scarcity of fresh water resources is driving many countries in the arid and semi arid regions to use municipal waste water, for irrigation with waste water is said to have both beneficial and harmful effects as it contains substantial amounts of beneficial nutrients and toxic heavy metals ( Chen et al., 2005; Singh et al., 2004). Reliability and …

Introduction Ballizing ( Contact Pressure and Force) The explanation is that the relationship between the contact area and the force is near linear for these materials, and therefore the contact pressure as a ratio of force to area is practically constant. In the case of hard metals (for example hardened steels) the significant elasticity causes the contact area to increase …

Introduction Schiff bases have often been used as chelating ligands in the field of coordination chemistry and their metal complexes are of great interest for many years. It is well known that N and S atoms play a key role in the coordination of metals at the active sites of numerous metallobio molecules.1 Schiff base metal complexes have been widely …

Introduction An important and fundamental property of a semiconductor material is its dielectric permittivity which arises due to the difference in electro negativities of the constituent atoms in a binary / mixed semiconductor compound. A thorough knowledge of this parameter is essential for solving many problems in semiconductor Physics, particularly in the electric field stimulated emission studies in presence of …

Introduction The coordination chemistry of transition metals with ligands from the uranyl family hasbeen of interest due to different bonding modes shown by these ligands with both electron rich and electron poor metal. In principle, the central transition metal atoms of different soft and hard Lewis acidity usually need to be satisfied in the most suitable fashion.Schiff base metal complexes have been widely studied because they have industrial, antifungal, …

Introduction So what makes a material deform at high temperature, but not at room temperature? To understand that we first need to understand how a metal deforms in the first place. What makes metals ‘ductile’? The answer to this question can very easily be visualized by examining how a caterpillar moves. As we all know, a caterpillar first creates a …

Introduction Nonlinear Optical (NLO) materials crystals are of considerable interest and of great demand because of their different applications in science and technology, such as different harmonic generators, sum and different generators and parametric oscillators.1-2 The inorganic and organic class of NLO materials is also available with different merits and demerits.3-4 The semi-organic class of NLO materials possesses both the properties of …

Introduction Cumene is the common name for isopropylbenzene, an organic compound that is an aromatic hydrocarbon. It is a constituent of crude oil and refined fuels. It is a flammable colorless liquid that has a boiling point of 152°C. Nearly all the  cumene that is produced as a pure compound on an industrial scale is converted to cumene hydroperoxide, which …

Introduction Heusler alloys are the ternary intermetallich compounds with compostion X2YZ, where X and Y are transition elements (Ni, Co, Fe, Mn, Cr, Ti, V etc.) and Z is III, IV or V group elements (Al,Ga, Ge, AS, Sn, In etc.). One of the promising classes of materials is the half-metallic ferrimagnets, i.e., compounds for which only one spin channel …

Introduction The proposed research will have a direct impact on production process, such as precision tube sizing. Sizing of bushes etc, and final results will be of utility to industries. This will help in achieving high precision by selecting appropriate “Ball-Tube” combination.  Other carbon steels and alloy steels with harder balls. Ballizing could be done on soft metals like zinc. …

Introduction The ionic conducting Solid Polymer Electrolyte (SPEs) show tremendous technological power sources viz. flexible, compact, light-weight, leak-proof, thin film micro-batteries of desirable shape/size.1-4 The conduction mechanism in polymer electrolyte was reported for the first time in 19735, while the first practical SPE battery based on ‘Poly(ethylene oxide) (PEO)-Li+ -ion salt complex’ was demonstrated in 1979.6 Since then, a wide variety of …

Introduction Ball burnising used the surface integrity must be maintained Plastic deformation, micro- crack, phase transformation and residual stress. It is a cold working process and involves plastic deformation under cold working conditions by pushing hard. The burnishing process help to improve surface roughness super finishing. Mathematical models incorporating the effect of speed, hardness of work piece on the surface …

Introduction Bis amides have often been used as chelating ligands in the field of coordination chemistry and their metal complexes are of great interest for many years. It is well known that N atom plays a key role in the coordination of metals at the active sites of numerous metallobio molecules.1 Bis amides metal complexes have been widely studied because …

Introduction Several field theory models on k- space time have been constructed , using different techniques such as by F. Mejer and J Lukierski specially in, scalar field theory on k-Minkowski space. It has been shown by S. Tanimutra that in the flat space time, Feynman approach and minimal coupling method are equivalent which is usefull to derive the general …

Introduction Chloroethyl derivatives are new agents that have shown promising cytotoxic and antineplastic activities. The cytotoxicity of many chloroethyl derivatives was demonstrated on several tumor cell lines.1 Kulkarni et al.,2 reported the quantitative structure activity relationship studies of chloroethyl derivatives. Nonlinear optics deals with the interaction of applied electromagnetic fields in various materials to generate new electromagnetic fields, altered in …

Introduction Smart materials are materials with properties that can be significantly altered in a controlled fashion by external stimuli, such as stress, temperature, pH, moisture, electric or magnetic fields. Especially materials, which can respond to the changes in their environment in a very short time, are currently developed. An elastomer comprising a matrix interspersed with micron sized ferromagnetic particles is …

Introduction Electrical Discharge Machining (EDM) is a unconventional manufacturing process based on removal of material from a part by means of a series of repeated electrical sparks created by electric pulse generators at short intervals between a electrode tool and the part to be machined emmersed in dielectric fluid. At present, EDM is a widespread technique used in industry for …

Introduction The future development of nuclear waste energy depends largely on the success of programmes for handling and management of radioactive wastes generated at various stages of the nuclear fuel cycle. Besides fission products, in a reprocessing of spent fuel operation, the waste contains unrecovered U, Pu, corrosive products like Fe, Co, Ni, Al, Na and anions NO3 – and SO42-. …

Introduction Polyfunctionally rings compounds and synthesis of their metal complexes which have various biological activities and include hetero atom, have been formed in organic synthesis and coordination chemistry.1-3 Many trasition and inner trasition metal complexes have been synthesized for analytical and commercial applicatisis many of medicinal use.4-5 Literature survey reveals that the transition metal complexes generally crystallized with tetrahedral, octahedral geometry.6-3 Table …

Introduction The dielectric relaxation studies are one of the useful techniques to elucidate the nature of interactions that exist in solute-solvent component of a system.1-3 Jianhuattu et al have studied the excess enthalpies, excess isobaric heat capacities, densities and speeds of sound of the mixtures ethyl formate + benzene, + ethanol, and + 2,2,2- trifluoroethan-1-ol, at 298.15 K.4 Ethylformate is …

Introduction   A heat exchanger is a device in which energy is transferred from one fluid to another across a solid surface. Exchanger analysis and design therefore involve both convection and conduction. Two important problems in heat exchanger analysis are1 rating existing heat exchangers and (ii) sizing heat exchangers for a particular application. Rating involves determination of the rate of …

Introduction The supply of clean energy for our society is a central challenge to maintain our standard of living. It is important to change from fossil fuels to renewable energy sources for two main reasons: Firstly, the natural resources of gas and oil are limited and will run out. Secondly and more importantly, a continued dependence on fossil fuels would …

Introduction Schiff bases have often been used as chelating ligands in the field of coordination chemistry and their metal complexes are of great interest for many years. It is well known that N and S atoms play a key role in the coordination of metals at the active sites of numerous metallobio molecules1. Schiff base metal complexes have been widely …

Introduction Dyeing is a process not only of mass transfer but also one in which interaction in different degree between dye and fibre take place. Thus, the inclusion of thermodynamic sorption data is essential1,2. The application of physical chemistry to dyeing process led to the concept of “dyeing affinity”. That is the free-energy change accompanying dye adsorption process, as a …

Introduction In material science, the strength of a material is its ability to withstand an applied stress without failure, the applied stress may be tensile, compressive, or shear. A load applied to a mechanical member will induce internal forces within the member called stresses. Those stresses acting on the material cause deformations of the material. Deformation of the material is …

Introduction Thermoluminescence (TL) appears when a solid sample (usually an insulator or semiconductor )is heated after being irradiated ata low temperature T0. Part of the energy absorbed by the sample in course of irradiation may be released during heating. Thermoluminescence has found important application in dating and dosimetry. The rigorous theory of thermoluminescence is very complicated. The most popular model of …

Introduction Acoustic emission is defined as “the class of phenomena whereby transient elastic waves are generated by the rapid release of energy from localized sources within a materials or the transient elastic waves so generated”1. During manufacturing process of metal every care is taken to have sound metallurgical microstructure. In thermal power plant the components are subjected to high temperatures …

Introduction Mixed semiconducting materials, especially the Cadmium chalcogenides, form a technically important class of materials because of their wide spread utility in a variety of opto-electronic devices. The main reason for this utility was that their optical energy gaps could be tailored to match with a sensitive region of the visible spectrum and they possess effectively high photosensitivity over a …

Introduction Energy plays a vital role in the social, economic, industrial and agricultural growth and comprehensive development of a country. World wide per capita energy consumption is increasing due to rapid industrialization, urbanization and growth in transport and service sector. There is a need to maintain a balance between power generation and environmental health. Power production through fossil fuels particularly …

Introduction The research on superhydrophobic surfaces and the related phenomenon of high contact angles dates back a long time 1-7. Besides, superhydrophobic surfaces with a water contact angle higher than 90° have attracted great attention because of their importance in industrial applications. In general, a superhydrophobic surface can be prepared by combination of the surface lowering the surface free energy …

Introduction Study of Fundamental physical – chemical, mechanical, thermal and thermodynamic properties and the resulting information is the reliable scientific basis for a successful search and development of new compounds and materials with predetermined properties. Such studies for metallic systems based on aluminum and lanthanides are particular relevance. Widespread use of compounds of these metals, due to make special, sometimes …

Introduction Tungsten has the highest melting point and lowest vapour pressure amongst all metals. In addition, it has excellent high temperature strength and hardness of the four common refractory metals. These unique combinations of properties are tailor-made for certain applications. One such application is for the manufacture of filaments. Tungsten lamp filaments must operate at high temperature for long times …

Introduction Nowadays, considerable amount of work is being carried out in the field of polymers and many workers are trying to obtain good quality conducting layer on a polymer. Alkali metals Lithium and Sodium are elements which when doped in a polymer changes the surface resistivity. Chemical methods are used to dope these metals on polymers. Material and Methods A …

Introduction Diffusion of silicon with Aluminium is normally carried out to control electrical characteristics of silicon and also to manufacture semiconductor devices. It is known that different grain size alumina powders are used to polish crystalline silicon to meet experimental requirements. It may be possible that during polishing, aluminium atoms get diffused in silicon. However, so far no attention has …

Introduction Corrosion of materials is burning problems for industry, railways, housing, transport vehicle, bridge and sensitive equipments. It generally takes place with metals, alloys, polymers, woods, glass and ceramics due to interaction of material with pollutants, effluents, industrial waste, human waste, biological waste, municipal waste, sea water, humid environment, acid rains, emissions, chemical by product, micro-organic and macro-organisms as well …

Introduction Mechanoluminescence (ML) can be excited by cutting cleaving. grinding rubbing, compressing or by impulsive deformation of solids.1 It is also produced during the deformation caused by drastic cooling or heating of solids5 The ML can be excited by the shock-waves produced during exposure of the materials to laser pulses.6 Fracture of alkali halide crystals along (100) planes is called cleavage. When crystals …

Introduction The 14 MeV neutron generator1 used for the present work generates neutrons of energy 14.77 MeV and has a flux of 108 n/cm2/sec. When a sample is irradiated then the induced activity 2 in the sample is A=N σ F Where A, N, σ and F denote activity induced in the irradiated sample, the neutron flux, cross-section of the reaction …

Introduction Thermoluminescence (TL) is a luminescence phenomenon of a semiconductor or insulator which can be observed when the solid is thermally stimulated after being irradiated by some ionizing radiation. In TL experiments, a sample, after irradiation is heated in a oven according to some pre-programmed temperature profile. Among the heating schemes applied, linear heating scheme is the most widely used …

Introduction The development of biological sensors, or biosensors, is a rapidly growing field and scientists in areas as diverse as chemistry, biotechnology, mechanical engineering and electrical engineering are working to create biosensors that have medical and industrial applications.1 These researchers employ technologies as cutting edge as stretchable electronics and as simple dipstick tests, using materials as exotic as silk in ancient …

Introduction Clay was one of the earliest materials used to produce ceramics. Two types of clay are generally used which are often termed an china clay and ball clay. Both are Kaolinitic in nature; contain quartz as major impurities mineral along with iron oxide and titania as minor impurities. Ball clays are finer than china clay and often refered to …

Introduction In the recent past the structural and electrical studies of magnetic multilayers have been intensely pursued.1 For example, [Ni(86Å)/ Fe(29Å)]11 multilayer was probed for texture and magnetic properties as a function of deposition temperature.2 An irradiated multilayer, [Ni(13Å/ Fe(33Å)]10 with swift heavy ions was studied for magneto-optic Kerr effect and electrical resistivity as a function of temperature.3 The interface mixing leading to …

Introduction The Duplex stainless steels (DSS) have two-phase microstructure of ferrite (α) and austenite (γ) in which austenite phase is distributed as coarse regions in a ferrite phase matrix.1 Simultaneous presence of ferrite and austenite phases provides a combination of the best properties of these two phases; better corrosion resistance than austenitic stainless steels and better mechanical properties than ferritic stainless …