Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum gravity (QG), which predict a vacuum refractive index similar or equal to 1 + (E/M-QGn)(n), n = 1, 2. Parametrizing the delay between gamma-rays of different energies as Delta t = +/-tau E-1 or Delta t = +/-tau E-q(2), we find tau(1) = (0.030 +/- 0.012) s/GeV at the 2.5-sigma level, and tau(q) = (3.71 +/- 2.57) x 10(-6) s/GeV2, respectively. We use these results to establish lower limits M-QG1 > 0.21 X 10(18) GeV and M-QG2 > 0.26 x 10(11) GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

Developing A Knowledge Management Process Model for Internal IT Organization, Case: Stora Enso Oyj, Corporate IT

The objectives of this Master’s Thesis were to find out what kind of knowledge management strategy would fit best an IT organization that uses ITIL (Information Technology Infrastructure Library) framework for IT Service Management and to create a knowledge management process model to support chosen strategy. The empirical material for this research was collected through qualitative semi-structured interviews of a case organization Stora Enso Corporate IT. The results of the qualitative interviews indicate that codification knowledge management strategy would fit best for the case organization. The knowledge management process model was created based on earlier studies and a literature of knowledge management. The model was evaluated in the interview research and the results showed that the created process model is realistic, useful, and it responds to a real life phenomenon.

Calculation of radio electrical coverage in Medium-Wave Frequencies

The aim of this project is to accomplish an application software based on Matlab to calculate the radioelectrical coverage by surface wave of broadcast radiostations in the band of Medium Wave (WM) all around the world. Also, given the location of a transmitting and a receiving station, the software should be able to calculate the electric field that the receiver should receive at that specific site. In case of several transmitters, the program should search for the existence of Inter-Symbol Interference, and calculate the field strenght accordingly. The application should ask for the configuration parameters of the transmitter radiostation within a Graphical User Interface (GUI), and bring back the resulting coverage above a map of the area under study. For the development of this project, it has been used several conductivity databases of different countries, and a high-resolution elevation database (GLOBE). Also, to calculate the field strenght due to groundwave propagation, it has been used ITU GRWAVE program, which must be integrated into a Matlab interface to be used by the application developed.

Uma introdução à espectroscopia atômica: II - o espectro do sódio

The present article is devoted to Chemistry or Physics undergraduate students, given their difficulty to understand fundamental concepts and technical language used in atomic spectroscopy and quantum mechanics. An easy approach is shown in the treatment of the emission spectrum of the sodium atom without any involved calculations. In a previous article, the hydrogen spectrum was considered and the energy degeneracy of the angular momentum quantum number was observed. For the sodium spectrum, due to the valence electron penetration into internal shells, a breakdown of this degeneracy occurs and a dependence of this penetration on the angular momentum quantum number is observed. The eigenvalues are determined introducing the quantum defect correction (Rydberg correction) in the denominator of the Balmer equation, and the energy diagram is obtained. The intensity ratio for the observed doublets is explained by introducing new wave functions, containing the magnetic quantum number of the total angular momentum.

El juego y su estructura interna en relación con el trabajo de la condición física en primaria = Games and their internal structure in relation to the work of physical condition in Primary Education

One of the methodological resources that teachers use in a generalised way in Physical Education classes is the game. Inthis article we define the concept of game and analyse the characteristics of their internal structure. On the other hand welook at the concepts of physical condition and conditional skills and describe the objectives of its work in Primary Education.Finally, we relate these concepts and propose two practical examples of modifying the internal structure of the game so asto produce variations in the implied conditional skills

Determination of 5-aminosalicylic acid in pharmaceutical formulations by square wave voltammetry at pencil graphite electrodes

An analytical method for the determination of the anti-inflammatory drug 5-aminosalicylic acid (5-ASA) in pharmaceutical formulations using square wave voltammetry at pencil graphite electrodes was developed. After the optimization of the experimental conditions, calibration curves were obtained in the linear concentration range from 9.78 × 10-7 to 7.25 × 10-5 mol L-1 resulting in a limit of detection of 2.12 ± 0.05 x 10-8 mol L-1. Statistical tests showed that the concentrations of 5-ASA in commercial tablets and enemas obtained with the proposed voltammetric method agreed with HPLC values at a 95% confidence level.

Internal standard versus external standard calibration: an uncertainty case study of a liquid chromatography analysis

Traditionally, in the cigarettes industry, the determination of ammonium ion in the mainstream smoke is performed by ion chromatography. This work studies this determination and compares the results of this technique with the use of external and internal standard calibration. A reference cigarette sample presented measurement uncertainty of 2.0 μg/cigarette and 1.5 μg/cigarette, with external and internal standard, respectively. It is observed that the greatest source of uncertainty is the bias correction factor and that it is even more significant when using external standard, confirming thus the importance of internal standardization for this correction.

A simple square-wave voltammetric method for the determination of scopolamine in pharmaceuticals using a boron-doped diamond electrode

A simple procedure is described for the determination of scopolamine by square-wave voltammetry using a cathodically pretreated boron-doped diamond electrode. Cyclic voltammetry studies indicate that the oxidation of scopolamine is irreversible at a peak potential of 1.59 V (vs. Ag/AgCl (3.0 mol L-1 KCl)) in a 0.50 mol L-1 sulfuric acid solution. Under optimized conditions, the analytical curve obtained was linear (r = 0.9996) for the scopolamine concentration range of 1.0 to 110 µmol L-1, with a detection limit of 0.84 µmol L-1. The method was successfully applied to the determination of scopolamine in pharmaceutical formulations with minimum sample preparation.

Influence of internal seedborne Fusarium semitectum on cotton seedlings

Fusarium semitectum was found to be the major seed colonizing fungus in the commercial acid delinted cotton (Gossypium hirsutum) seed lots. There was no correlation, however, between its incidence and seedling emergence and disease symptoms on the emerged seedlings in autoclaved sand. Inoculation technique simulating internally seedborne nature of the fungus showed that the observed non-correlation might be related to the threshold level of seed coat colonization. The internally seedborne inoculum besides reducing seedling emergence, incited an array of symptoms on the emerged seedlings, which ranged from negative geotropism, leaf tearing, collar rot leading to dry root rot and seedling mortality. The dry root rot continued to develop on the plants surviving the seedling phase. The collar rot symptoms can be confused with those caused by Rhizoctonia solani.

Interaction study of moxifloxacin with Cu(II) ion using square-wave voltammetry and its application in the determination in tablets

This work presents an electroanalytical method for the determination of moxifloxacin (MOXI) in tablets by its interaction with Cu(II) ion and subsequent electrochemical reduction at hanging mercury drop electrode (HMDE). A well-defined reduction peak at -0.21 V vs. Ag/AgCl in Phosphate buffer 0.04 mol L-1 pH 8.0 was observed for the complex reduction MOXI-Cu(II), using square-wave voltammetry (SWV). Using a 10 s of accumulation time at -0.40 V was found a limit detection of 3.60x10-8 mol l-1. The obtained results have shown good agreement with those obtained by spectrophotometric method.

Determination of hydroquinone in a square wave voltammetry procedure using a graphite-polyurethane composite electrode

In order to a better characterization of a graphite-polyurethane composite intended to be used as a voltammetric sensor, the performance in a square wave voltammetric procedure was investigated. Using hydroquinone (HQ) as a probe, the electrode showed to be useful in square wave voltammetry with limit of detection of 0.28 µmol L-1, with recoveries between 99.1 and 101.5%. The results of the proposed method agreed with HPLC ones within 95% confidence level.

CFD Simulation of Two-phase and Three-phase Flows in Internal-loop Airlift

Airlift reactors are pneumatically agitated reactors that have been widely used in chemical, petrochemical, and bioprocess industries, such as fermentation and wastewater treatment. Computational Fluid Dynamics (CFD) has become more popular approach for design, scale-up and performance evaluation of such reactors. In the present work numerical simulations for internal-loop airlift reactors were performed using the transient Eulerian model with CFD package, ANSYS Fluent 12.1. The turbulence in the liquid phase is described using κ- ε the model. Global hydrodynamic parameters like gas holdup, gas velocity and liquid velocity have been investigated for a range of superficial gas velocities, both with 2D and 3D simulations. Moreover, the study of geometry and scale influence on the reactor have been considered. The results suggest that both, geometry and scale have significant effects on the hydrodynamic parameters, which may have substantial effects on the reactor performance. Grid refinement and time-step size effect have been discussed. Numerical calculations with gas-liquid-solid three-phase flow system have been carried out to investigate the effect of solid loading, solid particle size and solid density on the hydrodynamic characteristics of internal loop airlift reactor with different superficial gas velocities. It was observed that averaged gas holdup is significantly decreased with increasing slurry concentration. Simulations show that the riser gas holdup decreases with increase in solid particle diameter. In addition, it was found that the averaged solid holdup increases in the riser section with the increase of solid density. These produced results reveal that CFD have excellent potential to simulate two-phase and three-phase flow system.

Determinação do módulo de elasticidade em madeira laminada colada por meio de ensaio não destrutivo (''stress wave timer'')

As vigas estruturais de madeira são formas racionais do emprego da madeira na construção de estruturas, sendo obtidas pela associação de peças serradas e permitindo a utilização de tábuas com seções e comprimentos variados, além de combinações com madeira de qualidade diferenciada. Para atingir a resistência máxima de uma viga de madeira laminada colada, pode-se utilizar a classificação mecânica das peças por meio dinâmico. O objetivo deste estudo foi estabelecer correlação entre os métodos estático e dinâmico de classificação de vigas de madeira laminada. O trabalho foi desenvolvido com o emprego de peças de madeira serrada de Pinus taeda e adesivo resorcina fenolformaldeído. O processo de fabricação das vigas envolveu a classificação das peças, usinagem de emendas, formação das lamelas, montagem e prensagem das vigas. Já os ensaios envolveram a determinação do módulo de elasticidade por meio do ''stress wave method'' e de uma máquina universal de ensaios. Os resultados foram analisados pela análise de regressão do estabelecimento da equação de ajuste de correlação. O sistema de classificação visual utilizado na seleção de peças foi insuficiente para se atingirem os valores máximos de módulo de elasticidade; o posicionamento correto das lamelas por meio do método dinâmico de classificação teve como consequência direta o aumento do módulo de elasticidade da viga, e houve baixa correlação entre as formas de obtenção do módulo de elasticidade das vigas, não sendo possível a elaboração de equação adequada entre os métodos testados.

Estimativas das propriedades de compostos LVL produzidos com paricá (Schizolobium amazonicum Huber ex Ducke) por meio de stress wave

Foram avaliadas as propriedades físicas e mecânicas de compósitos LVL produzidos com a madeira de paricá (Schizolobium amazonicum Huber ex. Ducke), por meio de Stress Wave Timer. Os compósitos foram confeccionados em laboratório, dos quais foram retiradas amostras, que foram inicialmente destinadas à realização dos ensaios não destrutivos. Todas as amostras, com dimensões de 2,2 × 2,2 × 40 cm, foram ensaiadas, não destrutivamente, com a propagação de ondas nos sentidos flatwise e edgewise. Em sequência, as mesmas amostras foram destinadas à confecção de subamostras, para realização dos ensaios destrutivos, físicos (absorção de água, inchamento em espessura e inchamento residual) e mecânicos (resistência e rigidez à flexão estática flatwise; resistência e rigidez à flexão estática edgewise; resistência à compressão paralela e resistência ao cisalhamento paralelo e perpendicular). A velocidade de propagação das ondas (V0) e o módulo de elasticidade dinâmico (Emd), obtidos com o auxílio do Stress Wave, foram utilizados para elaboração de modelos de predição das propriedades avaliadas. Os resultados indicaram que o Stress Wave Timer apresenta resultados satisfatórios para predição das propriedades mecânicas de compósitos LVL. Com relação às propriedades físicas, embora tenham sido verificados modelos com ajustes significativos, constatou-se limitação dessa ferramenta para predição desses parâmetros. Contudo, considerando ambas as propriedades, físicas e mecânicas, os melhores ajustes foram observados em amostras ensaiadas com a propagação de ondas no sentido edgewise e com o uso da variável independente Emd.