A low-cost ultrasonic spray dryer to produce spherical microparticles from polymeric matrices

The spray-drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because it leads to rapid solvent evaporation from droplets. This method involves the transformation of a feed from a fluid state into a dried particulate, by spraying the feed into a hot medium. Despite being most often considered a dehydration process, spray drying can also be used as an encapsulation method. Therefore, this work proposes the use of a simple and low-cost ultrasonic spray dryer system to produce spherical microparticles. This equipment was successfully applied to the preparation of dextrin microspheres on a laboratory scale and for academic purposes.

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.

Laüe back-reflection method for crystallographic orientation of a martensitic Cu-Zn-Al single crystal of the monoclinic system

A martensitic single crystal Cu-23.95Zn-3.62(wt.%)Al alloy was obtained melting pure Cu, Zn and Al using Bridgman's method. The martensitic phase (monoclinic) can present up to 24 variants, and orienting the surface according to a certain plane is a very hard task. The single crystal was submitted to 8 tons of tension (stress) along the longitudinal direction to reduce the number of variants and facilitate the surface orientation according to the desired plane. This single crystal was oriented using the Laüe back-reflection method to give surfaces with the following oriented crystallographic planes: (010), (120) and (130). It was observed that the tension stress was applied along the [010] direction.

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.

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.

DESENVOLVIMENTO DE UMA TÉCNICA ULTRASSÔNICA PARA AVALIAR TEORES DE ÓLEO E GRAXA EM EFLUENTES DE BIOCOMBUSTÍVEIS

Ultrasound as a metrology tool has many applications in health care, industrial, and chemical analyses. Ultrasonic techniques are rapid, low-cost, non-invasive, and highly repeatable. Although ultrasound can be used to measure emulsions, no effort had been made thus far to optimize its sensitivity for metrological analysis. In this work, a technique for analyzing oil in water was validated. The wave velocity and attenuation were chosen as the ultrasonic parameters. The technique was implemented in the boundary region established by law for effluents from industrial plants involved with biofuel manufacturing. A technical effort of this study was to establish stable emulsions in concentrations close to the desired limit of study. The phase behaviours of pseudo-ternary oil, sodium chloride, and sodium lauryl sulphate were studied. The composition in the widest region of the diagram allowed for the formation of a stable emulsion, from which the ultrasound measurement was carried out. An analytical curve was obtained using ultrasonic attenuation to determine the content of oils and greases in wastewater ranging 15–240 ppm. The speed of sound did not appear to be an applicable parameter for this application. The technique was demonstrated to be an important alternative solution for the continuous monitoring of wastewater with regard to oil concentrations.

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.

Preparation of nano-MgO using ultrasonic method and its characteristics

MgO is an important inorganic material, which can be used in many aspects, such as catalyst, toxic-waste remediation agent, adsorbent, and others. In order to make use of MgO, nano-MgO was prepared by ultrasonic method using Mg (CH3COO)2.2H2O as precursor, NaOH aqueous solution as precipitant in this paper. Effect factors on MgO nano-particle size were investigated. Characteristics of samples were measured by TGA, XRD, TEM, and others techniques. The results showed that the size of nano-MgO about 4 nm could be obtained under the following conditions (ultrasonic time 20 min, ultrasonic power 250 W, titration rate of NaOH 0.25 mL/min, NaOH concentration 0.48 mol/L, calcinations temperature 410 °C, calcination time 1.5 h, heating rate of calcination 5 °C/min). It was a very simple and effective method to prepare nano-MgO.

Dialogue in the crisis of representation : realism and antirealism in the context of the conversation between theologians and quantum physicists in Göttingen 1949-1961

The aim of this study is to analyse the content of the interdisciplinary conversations in Göttingen between 1949 and 1961. The task is to compare models for describing reality presented by quantum physicists and theologians. Descriptions of reality indifferent disciplines are conditioned by the development of the concept of reality in philosophy, physics and theology. Our basic problem is stated in the question: How is it possible for the intramental image to match the external object?Cartesian knowledge presupposes clear and distinct ideas in the mind prior to observation resulting in a true correspondence between the observed object and the cogitative observing subject. The Kantian synthesis between rationalism and empiricism emphasises an extended character of representation. The human mind is not a passive receiver of external information, but is actively construing intramental representations of external reality in the epistemological process. Heidegger's aim was to reach a more primordial mode of understanding reality than what is possible in the Cartesian Subject-Object distinction. In Heidegger's philosophy, ontology as being-in-the-world is prior to knowledge concerning being. Ontology can be grasped only in the totality of being (Dasein), not only as an object of reflection and perception. According to Bohr, quantum mechanics introduces an irreducible loss in representation, which classically understood is a deficiency in knowledge. The conflicting aspects (particle and wave pictures) in our comprehension of physical reality, cannot be completely accommodated into an entire and coherent model of reality. What Bohr rejects is not realism, but the classical Einsteinian version of it. By the use of complementary descriptions, Bohr tries to save a fundamentally realistic position. The fundamental question in Barthian theology is the problem of God as an object of theological discourse. Dialectics is Barth¿s way to express knowledge of God avoiding a speculative theology and a human-centred religious self-consciousness. In Barthian theology, the human capacity for knowledge, independently of revelation, is insufficient to comprehend the being of God. Our knowledge of God is real knowledge in revelation and our words are made to correspond with the divine reality in an analogy of faith. The point of the Bultmannian demythologising programme was to claim the real existence of God beyond our faculties. We cannot simply define God as a human ideal of existence or a focus of values. The theological programme of Bultmann emphasised the notion that we can talk meaningfully of God only insofar as we have existential experience of his intervention. Common to all these twentieth century philosophical, physical and theological positions, is a form of anti-Cartesianism. Consequently, in regard to their epistemology, they can be labelled antirealist. This common insight also made it possible to find a common meeting point between the different disciplines. In this study, the different standpoints from all three areas and the conversations in Göttingen are analysed in the frameworkof realism/antirealism. One of the first tasks in the Göttingen conversations was to analyse the nature of the likeness between the complementary structures inquantum physics introduced by Niels Bohr and the dialectical forms in the Barthian doctrine of God. The reaction against epistemological Cartesianism, metaphysics of substance and deterministic description of reality was the common point of departure for theologians and physicists in the Göttingen discussions. In his complementarity, Bohr anticipated the crossing of traditional epistemic boundaries and the generalisation of epistemological strategies by introducing interpretative procedures across various disciplines.

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.