Arbuzov A.B.,Joint Institute for Nuclear Research |
Bytev V.V.,Joint Institute for Nuclear Research |
Kuraev E.A.,Joint Institute for Nuclear Research |
Tomasi-Gustafsson E.,IPN |
Bystritskiy Y.M.,Joint Institute for Nuclear Research
Physics of Particles and Nuclei | Year: 2010
In this review we consider the structure function method, based on the renormalization group approach: when combined with exact calculation at the lowest order of perturbation theory it allows one to calculate the differential cross sections in leading and next to leading order approximations, again providing the thousands accuracy. The implementation of this method to calculation of radiative corrections is also done for some processes on colliders. Among them radiative corrections to DVCS tensor, πe2 decay, Deep Inelasic Scattering, muon decay, Bhabha scattering, electron-positron annihilation and others. In some cases the explicit expression of non-leading terms (so called K-factor) is given or numerical estimation of it is done. © 2010 Pleiades Publishing, Ltd.
Fimbres-Castro C.,UABC |
Alvarez-Borrego J.,CICESE |
Optical Engineering | Year: 2012
We present a nonlinear correlation methodology to recognize objects. This system is invariant to position, rotation, and scale by using vectorial signatures obtained from the target such as those from problem images. Vectorial signatures are calculated through several mathematical transformations such as scale and Fourier transform. In this application, vectorial signatures are compared using nonlinear correlations. Also, experiments were carried out in order to find the noise tolerance. The discrimination coefficient was used as a metric in performance evaluation in presence of noise. In addition, spectral index and vectorial signature index are obtained in order to recognize objects in a simpler way. This technique has low computational cost. The invariance to position, rotation, and scale digital system was tested with 21 different fossil diatoms images. The results obtained are good, and the confidence level is above 95.4%. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).
Yris J.C.,UJAT |
Calleja H.,CENIDET |
Hernandez L.,IPN |
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2012
Among the photovoltaic (PV) systems, the ones interconnected to the electric system have presented a greater growth in the developed countries. In order to transform the generated DC energy in AC energy ready to be delivered to a grid, the concept of AC Module is applied. However, the problem of generating quality voltage to the network from a single PV module arises. As a solution, the topology of the buck-boost converter with tapped inductor (TI) is studied. The purpose is selecting a converter appropriated for an integrated PV inverter, with high benefits without isolation, applied to residential use with connection to a single-phase grid. Its performance is evaluated by means of the electronic simulator PSpice and it is verified with a prototype. From the collected data it is appreciated that the proposed inverter increases the voltage gain and the efficiency with respect to traditional converter. © 2012 IEEE.
The reduction of sulfur in the manufacture of gasoline and diesel generates large amounts of greenhouse gases, so specialists from the National Polytechnic Institute (IPN) in Mexico created an innovative catalytic material that removes this element, and its production requires only one day, representing an advantage in time and cost. The material consists of a catalyst composed of a transition metal called molybdenum, which removes sulfur in gasoline or diesel during hydrodesulfurization, which is the second stage of the distillation of petroleum, said Dr. Jose Domingo Cuesta Leal from the Center of Applied Scientific Research and Advanced Technology (CICATA). The innovation lies in a one-step synthesis methodology by which it is possible to obtain a catalyst with better qualities than current commercial products. Cuesta Leal explained that a hydrothermal reaction was used for the synthesis of the product. Its effect on a load of gas was evaluated after the amount of sulfur in the sample was measured and a reduction of 80 percent was obtained. Additionaly, in comparison with a commercial material under the same conditions, the one created at CICATA demonstrated better properties. The project can be adapted to any desired conditions, either as a compacted powder or small aggregates called pellets. This is the result of six years of research, time during which Dr. Cuesta Leal earned his master's and doctorate financed by the Mexican Council for Science and Technology (Conacyt). He adds that the sulfur removal benefits the oil refining process, avoiding corrosion and contamination by other catalysts such as platinum. Explore further: One sponge-like material, three different applications
Alvarez-Borrego J.,CICESE |
Optics Communications | Year: 2013
In this paper more alternative ways to generate the binary ring masks are studied and a new methodology is presented when in the analysis the image come with some distortion due to rotation. This new algorithm requires low computational cost. Signature vectors of the target so like signature vectors of the object to be recognized in the problem image are obtained using a binary ring mask constructed in accordance with the real or the imaginary part of their Fourier transform analyzing two different conditions in each one. In this manner, each image target or problem image, will have four unique binary ring masks. The four ways are analyzed and the best is chosen. In addition, due to any image with rotation include some distortion, the best transect is chosen in the Fourier plane in order to obtain the best signature through the different ways to obtain the binary mask. This methodology is applied to two cases: to identify different types of alphabetic letters in Arial font and to identify different fossil diatoms images. Considering the great similarity between diatom images the results obtained are excellent. © 2012 Elsevier B.V.