Pbte Quantum Dots - Sio2 Multilayers For Optical Devices Produced By Laser Ablation

Thin films of glass doped with PbTe quantum dots were successfully fabricated. The semiconducting quantum dots were grown by laser ablation of a PbTe target (99.99%) using the second harmonic of a Q-Switched Quantel Nd:YAG laser under high purity argon atmosphere. The glass matrix was fabricated by a plasma chemical vapor deposition method using vapor of tetramethoxysilane (TMOS) as precursor. The QD's and the glass matrix were alternately deposited onto a Si (100) wafer for 60 cycles. Cross-section TEM image clearly showed QD's layer well separated from each other with glass matrix layers. The influence of the ablation time on the size distribution of the quantum dots is studied. HRTEM revealed anisotropy in the size of the QD's: they were about 9nm in the high and 3-5 in diameter. Furthermore HRTEM studies revealed that the QD's basically growth in the (200) and (220) directions. The thickness of the glass matrix layer was about 20 nm. Absorption, photo luminescence and relaxation time of the multilayer were also measured.5734116123Alivisatos, A.P., (1996) Sci., 271, p. 933Warnock, J., Awschalom, D.D., (1985) Phys. Rev. B, 32, p. 5529Borrelli, N.F., May, D.W., Holland, H.J., Smith, D.W., (1987) J. Appl. Phys., 61, p. 399Potter, B.G., Simmons, J.H., (1988) Phys. Rev. B, 37, p. 10838Gleiter, H., (1989) Prog. Mater. Sci., 33, p. 223Tsunetomo, K., Shunsuke, S., Koyama, T., Tanaka, S., Sasaki, F., Kobayashi, S., (1995) Nonlinear Opt., 13, p. 109Reynoso, V.C.S., De Paula, A.M., Cuevas, R.F., Neto, J.A.M., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Electr. Lett., 31 (12), pp. 1013-1015Jacob, G.J., Cesar, C.L., Barbosa, L.C., (2002) Chem. Phys. Glass, 43 C, pp. 250-252Singh, R.K., Narayan, J., (1990) Phys. Rev. B, 41, p. 8843Barnes, J.P., (2002) Nanotechnology, 13, p. 465Tudury, G.E., Marquezini, M.V., Ferreira, L.G., Barbosa, L.C., Cesar, C.L., (2000) Phys. Rev. B, 62 (11), pp. 7357-7364Cesar, C.L., Jacob, G.J., Tudury, G.E., Marquezini, M.V., Barbosa, L.C., (2004) Atti della Fondazione G. Ronchi Journal, (4), pp. 519-528. , Anno LI

Numerical analysis of gas-solidsflow hydrodynamics and heat transfer in two outlet configurationindustrial riser using mesoscale theory to predict the interfacialdrag

Se analizan numéricamente dos configuraciones de un riser del proceso FCC variando la disposición de la salida superior, usando un modelo CFD en 2 D que incluye el Modelo de los Dos Fluidos (TMF), la Teoría Cinética del Flujo Granular (KTGF) y como modelo de arrastre el modelo de la Minimización de la Energía Multi-Escala (EMMS). El modelo se resuelve a través del programa ANSYS Fluent® 14.5 solucionando las ecuaciones de balance de masa, momentum y energía; y ecuaciones constitutivas para calcular la interacción entre las fases, la fase sólida con las paredes, y las propiedades de la fase granular. El modelo propuesto en este trabajo predice adecuadamente el comportamiento del flujo gas-sólido, prediciendo diferentes patrones de flujo en las coordenadas axial y radial del riser; así como zonas concentradas y diluidas de sólidos en la parte baja y alta del riser, respectivamente. Las fluctuaciones en la concentración y las velocidades de los sólidos tanto radial como axialmente que se observan son producto del alto grado de mezclado radial que se acentúa cerca de las paredes del riser debido al arrastre considerado por el modelo utilizado. Por otro lado se observa una rápida estabilización térmica radial y axial alcanzando en poco tiempo el estado estacionario. Los perfiles obtenidos en las dos configuraciones analizadas son muy similares, lo que motiva a que en trabajos futuros se analicen otras configuraciones de salida del riser que permitan mejorar los patrones de concentración y velocidades de los sólidos.In the FCC process two configurations riser are numerically analyzed varying the upper outlet orientation using a 2 D CFD model which includes the Two Fluid Model (TFM), Kinetic Theory of Granular Flow (KTGF), and Energy Minimization Multi-Scale (EMMS) theory as drag model. This model is solved using the ANSYS Fluent® 14.5 software, solving the governing equations of mass, momentum, and energy balance; and the constitutive equations to calculate interfacial interaction, wall-solid phase interaction, and granular phase properties. The model proposed in this work properly predicts the gas-solid flow behavior, predicting different solid flow patterns in radial and axial riser directions, as well as concentrated and diluted zones at riser's top and bottom respectively. The radial and axial solids concentration and velocities profiles fluctuations observed are produced by the high radial solid mix which is higher near the riser walls due to drag force considered by the model used. On the other hand, a rapid radial and axial thermal stabilization is observed reaching the steady state rapidly. The profiles obtained from riser configurations analyzed are very similar, so in future works other riser outlets configurations will be analyzed to try to improve the solid concentration and velocity profiles.Peer Reviewe

Genetic diversity and coefficient of parentage between clones and sugarcane varieties in Brazil

The success of the development of new sugarcane varieties is associated with the ability to correctly select the genitor. The aim of this study was to evaluate the genetic diversity between 113 clones and sugarcane varieties using the Ward-modified location model procedure with added information about the coefficient of parentage and endogamy. In this study, data was used from 100 experiments that evaluated clones; the experimental phase was conducted in 70 places between the years 2002 and 2009 on the outlining in random blocks. According to the diversity analysis, 3 groups formed: G1, G2, and G3, which were composed of 58, 8, and 47 genotypes, respectively. The clones of groups G1 and G3 were the most outstanding. Thus, biparental crossbreeding involving clones and varieties of these 2 groups can efficiently obtain transgressive genotypes. Knowledge of the heterotypic groups indicated by the Ward-modified location model method, along with the parentage information, will make it a lot easier to define the desirable and undesirable crossbreeds for public and private breeding programs that develop sugarcane varieties

Physical exercise on inflammatory markers in type 2 diabetes patients: a systematic review of randomized controlled trials

Background. Type 2 diabetes mellitus (T2DM) is a serious disease associated with high morbidity and mortality. Scientific findings showed that physical exercise is an option for treatment of these patients. This study's objective is to investigate the effects of supervised aerobic and/or resistance physical training on inflammatory markers in subjects with T2DM. Methods. A systematic review was conducted on four databases, MEDLINE, CENTRAL, LILACS, and Scopus, and manual search from 21 to 30 November 2016. Randomized clinical trials involving individuals diagnosed with T2DM, who have undergone supervised training protocols, were selected in this study. Results. Eleven studies were included. Studies that evaluated control group versus aerobic exercise reported controversial results about the effectiveness of physical training in modifying C-reactive protein (CRP) and cytokine levels. The only variable analyzed by the six studies in comparison to the control group versus resistance exercise was CRP. This protein showed no significant difference between groups. Between the two modes of exercise (aerobic and resistance), only one study demonstrated that aerobic exercise was more effective in reducing CRP. Conclusion. The evidence was insufficient to prove that aerobic or resistance exercise improves systemic levels of inflammatory markers in patients with T2DM

Implementation and calibration of finite-length plastic hinge elements for use in seismic structural collapse analysis

Finite-length plastic hinge (FLPH) models have shown advantages over the concentrated plasticity hinge (CPH) models. However, empirical phenomenological relationships, such as Modified Ibarra–Medina–Krawinkler (ModIMK) deterioration model, were mainly calibrated for use in CPH models. ModIMK relationships are versatile and have been applied to steel, reinforced concrete, and timber structures. Herein, a calibration procedure of FLPH models and a unified algorithm for use of ModIMK relationships in CPH and FLPH models are presented. Results from included examples validate the proposed algorithms, which were implemented in OpenSees. Additionally, results highlight that FPLH models avoid errors and convergence pitfalls of CPH models

Height-based equations as screening tools for elevated blood pressure in the SAYCARE study

This study evaluated the accuracy of four height-based equations: blood pressure to height ratio (BPHR), modified BPHR (MBPHR), new modified BPHR (NMBPHR), and height-based equations (HBE) for screening elevated BP in children and adolescents in the SAYCARE study. We measured height and BP of 829 children and adolescents from seven South American cities. Receiving operating curves were used to assess formula performance to diagnose elevated BP in comparison to the 2017 clinical guideline. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated for the four screening formulas. The diagnostic agreement was evaluated with the kappa coefficient. The HBE equation showed the maximum sensitivity (100%) in children, both for boys and girls, and showed the best performance results, with a very high NPV (>99%) and high PPV (>60%) except for female children (53.8%). In adolescents, the highest sensitivity (100%) was achieved with the NMBPHR for both sexes. Kappa coefficients indicated that HBE had the highest agreement with the gold standard diagnostic method (between 0.70 and 0.75), except for female children (0.57). Simplified methods are friendlier than the percentile gold standard tables. The HBE equation showed better performance than the other formulas in this Latin American pediatric population

Two-photon Absorption In Direct Bandgap Semiconductors Quantum Dots

We present degenerate and nondegenerate two-photon absorption spectra in a series of CdSe and CdTe quantum dots. The measurements show that the two-photon absorption (2PA) spectrum is strongly dependent on the quantum dot size and that the 2PA coefficient decreases as the quantum dot size decreases, and it is larger for the frequency nondegenerate process. Previously we had shown a theoretical analysis of these results based on a simple model using the effective mass approximation. Although this model works well for larger quantum dots, it fails for the smaller ones. Here we use the more realistic k→ p→ model for the band structure and consider the hole band mixing in quantum dots to describe our data. This theory better describes the spectral structures for smaller quantum dots and also predicts the decrease of the 2PA coefficient with the decrease of quantum dot size. This is due to the reduction of the number of possible transitions and the blue shift of the optical bandgap from quantum confinement. This theory predicts the reduction of the 2PA coefficient with size, although our experimental results show an even stronger reduction.6327Larson, D.R., Zipfel, W.R., Willians, R.M., Clark, S.W., Bruchez, M.P., Wise, F.W., Webb, W.W., (2003) Science, 300, pp. 1434-1436Sargent, E.H., (2005) Adv. Matt., 17, pp. 515-522Padilha, L.A., Neves, A.A.R., Rodriguez, E., Cesar, C.L., Barobosa, L.C., Cruz, C.H.B., (2005) Appl. Phys. Lett., 86, pp. 1611111-1611113Uskov, A.V., O'Reilly, E.P., Manning, R.J., Webb, R.P., Cotter, D., Laemmlin, M., Ledentsov, N.N., Bimberg, D., (2004) IEEE Phot. Tech. Lett, 16, pp. 1265-1267Cerletti, V., Coish, W.A., Gywat, O., Loss, D., (2005) Nanotech., 16, pp. R27-R49Sercel, P.C., Vahala, K.J., (1990) Phys. Rev. B, 42, pp. 3690-3710Cotter, D., Burt, M.G., Manning, R.J., (1992) Phys. Rev. Lett., 68, pp. 1200-1203Seo, J.T., Yang, Q., Creekmore, S., Temple, D., Qu, L., Yu, W., Wang, A., Kim, J.H., (2003) Phys. E, 17, pp. 101-103Banfi, G.P., Degiorgio, V., Ricard, D., (1998) Adv. Phys., 47, pp. 447-510Padilha, L.A., Fu, J., Hagan, D.J., Van Stryland, E.W., Cesar, C.L., Barbosa, L.C., Cruz, C.H.B., (2005) Opt. Exp., 13, pp. 6460-6467Padilha, L.A., Fu, J., Hagan, D.J., Van Stryland, E.W., Cesar, C.L., Barbosa, L.C., Cruz, C.H.B., (2005) Proc. SPIE, 5931, pp. 226-235Fedorov, A.V., Baranv, A.V., Inoue, K., (1996) Phys. Rev. B, 54, pp. 8627-8632Sheik-Bahae, M., Said, A.A., Wei, T.H., Hagan, D.J., Van Stryland, E.W., (1990) IEEE J. of Quantum Electron., 26, pp. 760-769Negres, R.A., Hales, J.M., Kobyakov, A., Hagan, D.J., Van Stryland, E.W., (2002) IEEE J. Quantum Electron., 38, pp. 1205-1216Hales, J.M., Hagan, D.J., Van Stryland, E.W., Schafer, K.J., Morales, A.R., Belfield, K.D., Pacher, P., Bredas, J.L., (2004) J. Chem. Phys., 121, pp. 3152-3160Barbosa, L.C., Reynoso, V.C.S., De Paula, A.M., De Oliveira, C.R.M., Alves, O.L., Craievich, A.F., Marotti, R.E., Cesar, C.L., (1997) J. Non-cryst. Solids, 219, pp. 205-211Yu, W.W., Qu, L.H., Guo, W.Z., Peng, X.G., (2003) Chem. Mater., 15, p. 2854Bunge, S.D., Krueger, K.M., Boyle, T.J., Rodriguez, M.A., Headley, T.J., Colvin, V.L., (2003) J. Mater. Chem., 13, p. 1705Qu, L.H., Peng, X.G., (2002) J. Am. Chem. Soc., 124, p. 2049L.A. Padilha, J. Fu, D.J. Hagan, E.W. Van Stryland, C.L. Cesar, L.C. Barbosa, C.H.B. Cruz, D. Buso, and A. Martucci, to be published (2006)Kane, E.O., Semiconductors & Semimetals, 1. , Cap. 3Ekimov, A.I., Hache, F., Schanne-Klein, M.C., Richard, D., Flytzanis, C., Kudryavtsev, I.A., Yazeva, T.V., Efros, Al.L., (1993) J. Opt. Soc. Am. B, 10, pp. 100-10

Application of reliability-based robustness assessment of steel moment resisting frame structures under post-mainshock cascading events

This paper proposes a reliability-based framework for quantifying structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of three, nine, and 20 stories, which were designed to pre-Northridge codes and standards. Two-dimensional nonlinear finite-element models of the buildings are developed with the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability based robustness indicator shows that the structural robustness is influenced by the extent to which a structure can distribute damage

Lactate and base deficit are predictors of mortality in critically ill patients with cancer

Cancer patients frequently require admission to intensive care unit. However, there are a few data regarding predictive factors for mortality in this group of patients. The aim of this study was to evaluate whether arterial lactate or standard base deficit on admission and after 24 hours can predict mortality for patients with cancer.Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe