39 research outputs found
A spherical perfect lens
It has been recently proved that a slab of negative refractive index material
acts as a perfect lens in that it makes accessible the sub-wavelength image
information contained in the evanescent modes of a source. Here we elaborate on
perfect lens solutions to spherical shells of negative refractive material
where magnification of the near-field images becomes possible. The negative
refractive materials then need to be spatially dispersive with and . We concentrate on lens-like solutions for the
extreme near-field limit. Then the conditions for the TM and TE polarized modes
become independent of and respectively.Comment: Revtex4, 9 pages, 2 figures (eps
Thermal Analysis to Estimate Heat Transfer From Heat Sink By Forced Convection Through Open Enclosure
Heat Exchanger is a device used to exchange the heat energy between the two fluids by which increases the operating efficiency. These efficiencies plays a major role for cost effective Operations in the process industries. While the both Fluids flow through the heat exchanger, the temperature of both fluids will exchange. The main objective of this paper is deals with the performance rate of double pipe heat exchanger by changing the materials which uses the heat input from the waste recovery of steam in refinery process. Double pipe heat exchangers are designed in CATIA and GAMBIT. CFD analysis is done by using ANSYS. Final Results are obtained with three different types of materials steel, aluminum and copper
Efficiency Improvement Of An Electrical Transformer By Design Development Of FINS
A transformer is an electrical gadget that exchanges electrical energy between two or more circuits through electromagnetic affectation. Normally, transformers are utilized to increment or diminish the voltages of exchanging current in electric force applications; a differing current in the transformer's essential winding makes a changing attractive flux in the transformer center and a shifting attractive field impinging on the transformer's auxiliary winding. This fluctuating attractive field at the auxiliary winding affects a shifting electromotive power (EMF) or voltage in the optional winding. Making utilization of Faraday's Law in conjunction with high attractive porousness center properties, transformers can along these lines be intended to proficiently change AC voltages starting with one voltage level then onto another within power networks. Copper losses are resistive and proportional to load current and are sometimes called “load losses”, as the transformer is loaded; heat is produced in the primary and secondary windings and connections due to losses. At low loads, the quantity of heat produced will be small but as load increases, the amount of heat produced becomes significant at full load, the windings will be operating at or near their design temperature, Figure shows the relationship between load-current and the heat produced in transformer windings and connections. If the ambient temperature is too high then the transformer will automatically fail to work , even though some coolants are employed in the transformers to carry away the heat, they are not enough during summer seasons so there is a need to develop better cooling systems In this project we develop better cooling system for a transformer using 3D modelling and Finite Element Methods so that the transformers will work without fail. For 3D modelling we use Catia V5 R20 and for finite element analysis we use Ansys 15.
Effect Of Thermal Load On Valve By Using Conventional Diesel And Blended Fuels
The valves used in the IC engines are of three types: Poppet or mushroom valve or Sleeve valve or Rotary valve. Of these three types, Poppet valve is most commonly used. Since both the inlet and exhaust valves are subjected to high temperatures of 500°C to 1200°C during the power stroke, therefore, it is necessary that the materials of the valves should withstand these temperatures. The temperature at the inlet valve is less compared to exhaust valve. Thus the inlet valve is generally made of nickel chromium alloy steel and exhaust valve is made of si-chrome steel.Automobile engines are usually petrol, diesel or gasoline engines. Petrol engines are Spark Ignition engines and diesel engines are Compression Ignition engines. Blended fuels are mixtures of traditional and alternative fuels in varying percentages. Here the effect of diesel blended fuels on valve is studied by mathematical correlations applying thermal loads produced during combustion. Blended fuels are usually bio fuels blended in different percentages. Percentages vary from 0%, 5%, 10% and 20%.Internal combustion engines produce exhaust gases at extremely high temperatures and pressures. As these hot gases pass through the exhaust valve, temperatures of the valve, valve seat, and stem increase. To avoid any damage to the exhaust valve assembly, heat is transferred from the exhaust valve through different parts, especially the valve seat insert during the opening and closing cycle as they come into contact with each other. In this thesis, a finite-element method is used for modeling the thermal analysis of an exhaust valve. The temperature distribution and resultant thermal fluxes are evaluated. Detailed analyses are performed to estimate the boundary conditions of an internal combustion engine. In this thesis, Catia is employed for modeling and Ansys is used for analysis of the exhaust valve
Delay times and reflection in chaotic cavities with absorption
Absorption yields an additional exponential decay in open quantum systems
which can be described by shifting the (scattering) energy E along the
imaginary axis, E+i\hbar/2\tau_{a}. Using the random matrix approach, we
calculate analytically the distribution of proper delay times (eigenvalues of
the time-delay matrix) in chaotic systems with broken time-reversal symmetry
that is valid for an arbitrary number of generally nonequivalent channels and
an arbitrary absorption rate 1/\tau_{a}. The relation between the average delay
time and the ``norm-leakage'' decay function is found. Fluctuations above the
average at large values of delay times are strongly suppressed by absorption.
The relation of the time-delay matrix to the reflection matrix S^{\dagger}S is
established at arbitrary absorption that gives us the distribution of
reflection eigenvalues. The particular case of single-channel scattering is
explicitly considered in detail.Comment: 5 pages, 3 figures; final version to appear in PRE (relation to
reflection extended, new material with Fig.3 added, experiment
cond-mat/0305090 discussed
Dynamic nuclear polarization and spin-diffusion in non-conducting solids
There has been much renewed interest in dynamic nuclear polarization (DNP),
particularly in the context of solid state biomolecular NMR and more recently
dissolution DNP techniques for liquids. This paper reviews the role of spin
diffusion in polarizing nuclear spins and discusses the role of the spin
diffusion barrier, before going on to discuss some recent results.Comment: submitted to Applied Magnetic Resonance. The article should appear in
a special issue that is being published in connection with the DNP Symposium
help in Nottingham in August 200
OUTLIER DETECTION IN DATA STREAM WITH TIMESTAMP IN LEARNING MODEL
Data stream is a collection or sequence of data instances of infinite length. Stream classification or online classification is more challenging task due to speed, diversity of concept or nature, type of distribution (linear or skewed), heterogeneous of data sources, lack of re-reading of instances and possibility of recurrence. This paper focuses on the concept drift under recurrence. The major challenge in data stream is handling of high volume of data of infinite length. Classification of instances under concept drift and recurrence is more difficult due to maintenance of past classifier results. To handle this situation in more efficient manner through swapping technique followed operating system’s demand paging concept with little modification
A model of fuel and energy sector contribution to economic growth
10.32479/ijeep.7849International Journal of Energy Economics and Policy9525-3
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Not AvailableA total of 1, 949 oesophagus and 355 meat samples (massetter or cervical region) collected from slaughtered buffaloes were examined by naked eye for presence of Sarcocysts (macro cysts) in different cities (Hyderabad, Mumbai, Kolkata and Delhi) of India. The overall prevalence of Sarcocysts (macro cysts) was 23.87%. A total of 102 tissue samples from oesophagus were subjected to histomorphological examination. The overall prevalence of Sarcocysts (micro cysts) was 60.78%.Not Availabl
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Not AvailableDNA was extracted from sarcocysts (visible on naked eye examination) collected from 168 buffaloes belonging to Mumbai (60), Hyderabad (54) and Kolkata (54) cities of India. They were subjected to PCR assay using 18S rRNA gene primer. All the PCR amplicons of about 900 bp were subjected to restriction enzyme digestion with four different restriction enzymes (BslI, DraI, FokI and RsaI). PCR amplicons showed two different patterns (Pattern A and Pattern B) on RFLP. Twenty one PCR products from Pattern A and one PCR product from Pattern B were subjected to DNA sequencing. S. fusiformis and S. taeniata were identified from Pattern A and S. buffalonis was identified from Pattern B on sequencing.Not Availabl