Entity

Time filter

Source Type

Mexico City, Mexico

Alvarez J.T.,ININ | De Pooter J.A.,Dutch Metrology Institute | Andersen C.,Riso High Dose Reference Laboratory | Aalbers A.H.L.,Dutch Metrology Institute | And 2 more authors.
Metrologia | Year: 2014

An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the Dutch Metrology Institute (VSL), The Netherlands, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the VSL in November 2009. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the VSL and the BIPM standards for reference air kerma rate, is 0.9873 with a combined standard uncertainty of 0.0061. Source


Gonzalez M.V.,National Autonomous University of Mexico | Jaime-Acuna O.E.,Research Center Cientifica Educacion Superior Of Ensenada | Escobar-Alarcon L.,ININ | Pawelec B.,ICP CSIC | Fierro J.L.G.,ICP CSIC
Applied Catalysis B: Environmental | Year: 2013

TiO2 and Fe(S)-doped TiO2 photocatalysts have been synthetized by a microwave-assisted method and deeply characterized by means of several techniques (N2 adsorption-desorption isotherms, scanning electron microscopy (SEM), TEM, high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), temperature-programmed desorption of NH3 (TPD-NH3) and UV-vis diffuse reflectance, Raman and XPS spectroscopic techniques). The synthetized samples were tested in the photodegradation of methyl red dye under UV irradiation at room temperature. Depending on the temperature and duration of the microwave synthesis, some changes in the textural and crystalline structure of the titanium dioxide were observed which influenced on the photocatalytic activity. The best photocatalyst found in this study was the one doped with S (0.1wt.%) prepared by microwave-assisted synthesis at 215°C for 60min and calcined at 550°C. The enhancement of color removal over this sample (49% of color removal) was associated to the formation of anatase phase and the enhancement of the sample acidity with respect to undoped TiO2 sample. A volcano-shaped curve was obtained for methyl red degradation against TiO2 crystal size. Catalyst calcination at 700°C led to a drastic drop in activity due to formation of large TiO2 crystals of rutile phase, as confirmed by XRD. © 2013 Elsevier B.V. Source


Quinones-Galvan J.G.,ININ | Sandoval-Jimenez I.M.,CINVESTAV | Hernandez-Hernandez L.A.,Escuela Superior de Fisica y Matematicas del IPN | de Moure-Flores F.,Autonomous University of Queretaro | And 4 more authors.
Results in Physics | Year: 2013

Polycrystalline transparent Zinc oxide thin films have been grown on glass substrates by the sol-gel technique using two different precursor solutions. The physical properties of the films were analyzed with X-ray diffraction, Atomic Force Microscopy, UV-Vis and Raman spectroscopy. The results show that the films grew in the hexagonal wurtzite structure. The band gap of the samples was estimated from UV-Vis measurements in values from 3.1 to 3.22. eV, these values are in agreement with those reported in the literature. Two different simple ways to obtain polycrystalline ZnO were developed and the properties of the films were studied as a function of the precursor solution. © 2013 The Authors. Source


Gonzalez H.E.,ININ | Carmona L.J.J.,ININ
International Journal of Engineering and Technology Innovation | Year: 2015

In this paper a parallel code for solving simultaneous linear equations with real coefficients are used. We postulate a new linear transformation in matrix product form and we apply this linear transformation to a matrix (A) and next we apply again this linear transformation to a vector (b) and so we obtain Cramer Rule solution of the linear system of equations in efficient way. We use subroutines of cuBLAS 2nd and 3rd levels in double precision and we obtain correct numeric results. Source


Romero J.T.A.,ININ | Hernandez-Oviedo O.,Medical Center | Tovar-Munoz V.M.,ININ
IFMBE Proceedings | Year: 2013

Introduction. Several publications had indicated the fail of conventional correction for air density k TP to x rays [1,2], for low energy [3,4] and 60Co photons [5] in dosimetry measurements with ionization chamber; therefore, it is necessary employ an additional correction factor for air density corrections k' PT . Objectives. (1).-To calibrate 125I seeds in terms Sk - for interstitial brachytherapy to treatment of prostate cancer- with and without this additional factor k' PT . (2).- To show that Sk values of a sample seeds are statistically equal within the relative expanded uncertainty ±7% (k=2) specify by the manufacturer. Method. (1) Nine 125I seeds, Amersham model 6711 are calibrated on Sk with an ionization well chamber traceable to Wisconsin University, following AAPM recommendations [6]. (2) The Tukey's ANOVA mean and ANOM test [7] are used to demonstrate the hypothesis H0: That S k mean values -without the additional correction- are statistically equal. Also is used the capability sixpack test (between/within) to verify the uncertainty claimed for the manufacturer, [8,9].Results. The k PT =1.3287±0.0047 and k' PT = 0.8966±0.0022, both for air density condition of 23.9 °C and 76.76 kPa; therefore (kPT)total=1.1913±0.0052 which is less 10.8% than the conventional k PT . For α=0.05 is rejected the H0, the mean test shows that the manufacturer's Sk value is inaccuracy 4% above the Sk great mean value with the k PT conventional correction- , nevertheless that uncertainty is consistent with the u c =3.5% established. Conclusions. The application of conventional k PT overestimates the Sk values for the environment conditions of the Mexican upland. The ANOVA mean test is a quality tool to accomplish the recommendations of the report 59 [10] to verify the manufacturer's Sk value. © 2013 Springer-Verlag. Source

Discover hidden collaborations