Descrições estruturais cristalinas de zeólitos

Crystalline structures of zeolites can be studied using different representations: the internal symmetry obtained by X-Ray or neutron diffraction crystallography techniques or a systematic analysis of the basic structural units which can be arranged to build the geometries of each kind of zeolite. In this work the basic concepts of three building units, SBU (Secondary Building Units), SSU (Structural SubUnits) and PBU (Periodic Building Units) are presented. The properties of the resulting crystalline structures are discussed (pores, cavities, channels), describing the influence of each one of these properties in processes of physical-chemical interest. Representative case studies of known zeolite crystalline structures are also discussed in terms of their space group classification.

Transferência de calibração em métodos multivariados

Calibration transfer has received considerable attention in the recent literature. Several standardization methods have been proposed for transferring calibration models between equipments. The goal of this paper is to present a general revision of calibration transfer techniques. Basic concepts will be reviewed, as well as the main advantages and drawbacks of each technique. A case study based on a set of 80 NIR spectra of maize samples recorded on two different instruments is used to illustrate the main calibration transfer techniques (direct standardization, piecewise direct standardization, orthogonal signal correction and robust variable selection).

Microextração em fase líquida (LPME): fundamentos da técnica e aplicações na análise de fármacos em fluidos biológicos

The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phase extraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase microextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.

O ensino de reações orgânicas usando química computacional: I. reações de adição eletrofílica a alquenos

Basic concepts that play an important role in some organic reactions are revisited in this paper, which reports a pedagogical experience involving undergraduate and graduate students. A systematic procedure has been applied in order to use widespread available computational tools. This paper aims to discuss the use of computers in teaching electrophilic addition reactions to alkenes. Two classical examples have been investigated: addition to non-conjugated alkenes and addition to conjugated dienes. The results were compared with those normally discussed in organic textbooks. Several important concepts, such as conformational analysis and energy control (kinetic and thermodynamic) involved in reaction mechanisms can be taught more efficiently if one connects theoretical and practical tools.

Hospital doctors' views and concerns about pharmacovigilance

Purpose: The aim of the study was to evaluate the opinions and concerns of hospital doctors about adverse drug reactions (ADRs) and pharmacovigilance. Methods: A qualitative study was undertaken using focus groups in sessions on pharmacovigilance activities conducted in thirteen clinical services of a tertiary university hospital. A total of 296 physicians participated in these sessions by giving their opinions or expressing their doubts about ADR and pharmacovigilance activities which were recorded by different observers and subsequently analysed. Results: Doctors remarked on: a) the importance, concern, frequency and specific types of ADRs that were observed in clinical practice; b) problems of clinical decision making related to the suspected ADRs; c) methods for improving detection and reporting ADRs; d) monitoring of specific ADRs or ADRs caused by specific drugs; e) and measures to prevent and minimize the risk of ADRs. Physicians expressed doubts related to: a) the basic concepts of ADRs; b) the methods of ADR identification and evaluation; c) the objectives and procedures of pharmacovigilance programmes; d) and the impact of pharmacovigilance activities. Conclusions: Hospital doctors believe that ADRs are a matter for concern in their daily clinical practice, and monitoring ADRs as well as measures for preventing the risk of ADRs are needed. Nevertheless, doctors have doubts about what an ADR is, the accuracy of diagnostic methods, the development of pharmacovigilance activities and their impact on clinical practice. Pharmacovigilance should be better explained through a continuous feedback and close relationship with hospital doctors.

Experimento didático de quimiometria para análise exploratória de óleos vegetais comestíveis por espectroscopia no infravermelho médio e análise de componentes principais: um tutorial, parte I

This manuscript aims to show the basic concepts and practical application of Principal Component Analysis (PCA) as a tutorial, using Matlab or Octave computing environment for beginners, undergraduate and graduate students. As a practical example it is shown the exploratory analysis of edible vegetable oils by mid infrared spectroscopy.

O tempo de pega em gelatinas comerciais: uma experiência da disciplina de quimiometria para estudantes de graduação em Química

The aim of this paper is to describe a chemometrics experiment for undergraduate chemistry students using basic concepts of experimental design to determine setting-time of commercial gelatins.

Estudo de reações químicas homogêneas via método de Monte Carlo

By using the Monte Carlo simulation platform with probabilistic mathematical functions of the Boltzmann type, , having activation energy and temperature as parameters, it was possible to assess important dynamic aspects of homogeneous chemical reactions of the types A → B and A B. The protocol proved a useful tool in work with the basic concepts of Kinetics and Thermodynamics allowing its application both in class activities and for assisting experimental procedures.

Experimento didático de quimiometria para calibração multivariada na determinação de paracetamol em comprimidos comerciais utilizando espectroscopia no infravermelho próximo: um tutorial, parte II

The aim of this manuscript was to show the basic concepts and practical application of Partial Least Squares (PLS) as a tutorial, using the Matlab computing environment for beginners, undergraduate and graduate students. As a practical example, the determination of the drug paracetamol in commercial tablets using Near-Infrared (NIR) spectroscopy and Partial Least Squares (PLS) regression was shown, an experiment that has been successfully carried out at the Chemical Institute of Campinas State University for chemistry undergraduate course students to introduce the basic concepts of multivariate calibration in a practical way.

Nanoestruturas de carbono (nanotubos, grafeno): Quo Vadis?

We describe general considerations about the present and the future standing of carbon nanostructures, mainly carbon nanotubes and graphene. Basic concepts and definitions, select structure/property relationships, and potential applications are reviewed. The analysis of the global market for these nanostructures, the commercial products available currently, the role of the chemistry, the main challenges remaining and a brief view of the field in Brazil are also presented and discussed.

Eletrocromismo: fundamentos e a aplicação de nanomateriais no desenvolvimento de eletrodos de alto desempenho

This review deals with the basis and novel trends in electrochromism, describing the basic aspects and methodologies employed for the construction and analyses of different modified electrodes. The work presents the classic materials used for the construction of electrochromic electrodes, such as WO3 and a view on the basic concepts of chromaticity as a useful approach for analyzing colorimetric results. The report also addresses how the incorporation of nanomaterials and the consequent novel modification of electrodes have furthered this area of science, producing electrochromic electrodes with high performance, high efficiency and low response times.

PREPARAÇÃO DE PONTOS DE CARBONO E SUA CARACTERIZAÇÃO ÓPTICA: UM EXPERIMENTO PARA INTRODUZIR NANOCIÊNCIA NA GRADUAÇÃO

Carbon dots (CDs) constitute a new class of carbon-based nanomaterials that measure less than 10 nm and display attractive physical and chemical features such as fluorescence. CDs have been considered the new “power” carbon nanomaterials since their accidental discovery in 2004. This study reports a simple, easy, and accessible experiment for undergraduate courses. The experiment involves the preparation of CDs by pyrolysis using commercial gelatin as a low cost precursor as well as CD purification and optical characterization. The optical properties of CDs such as absorption and emission properties make them a promising material for teaching the basic concepts and techniques used for characterization of nanomaterials. Also, the reactants and final product are suitable for undergraduate courses since they are non-toxic materials. The prepared CDs can be used in such applications as bioimaging, solar cells, and photocatalysis.

RFID tekniikan käyttömahdollisuudet betonituoteteollisuuden varastonhallinnassa

Lujabetoni Oy:n kappaletavaran varastonhallinnassa on todettu paljon kehitettävää. Kappaletavaran varasto-otot eivät perustu todellisiin määriin, varastonkierto on hidasta, varastointi sitoo paljon pääomaa ja inventointi on työlästä. Tähän ongelmaan haetaan ratkaisua RFID –teknologiasta. Työn teoriaosassa on käsitelty RFID –teknologian teoriaa ja nykytilaa, sekä varastoinnin peruskäsitteitä ja varastonohjausmenetelmiä. Empiirisessä osassa on laadittu RFID –järjestelmän toteutussuunnitelma. Työn tuloksena on RFID –järjestelmän kuvaus sekä toteutussuunnitelma, joilla saavutetaan tavoitellut hyödyt. Työssä löydettiin menetelmät joilla komponentit voidaan luotettavasti tunnistaa, sekä suunniteltiin todellisiin tapahtumiin perustuva, automaattiset vastaanotto- ja varasto-otto –kirjaukset mahdollistava RFID –järjestelmä. Näiden ansiosta varastotyö ja varastoihin sitoutuva pääoma vähenevät, jolloin saavutetaan säästöjä varastointikustannuksissa.

Compliance of crane electrics with electrical safety standards and codes

Master’s thesis focuses on the questions of crane electrics compliance with electrical safety standards. Overview and short comparison of the world’s effective standards in the field is made in order to understand their demands. Basic concepts of a proper electrical circuit design are presented. Characteristics, construction and operation principles of overcurrent protective devices are studied in details. Electrics of the basic crane is designed according to the assumed customer’s demands, compliance with the requirements of the standards is checked. Solutions to achieve better compliance in some issues are proposed. Accent is made on the National Electrical Code (NEC) and standards by Underwriters Laboratories (UL) latests demands. Requirements of the International Electrotechnical Commission (IEC) are also taken into account.

Det pedagogiska övervägandet : en uppmärksamhetsriktande studie i och genom humanvetenskaplig handlingsteori

Det övergripande syftet med avhandlingen är att bidra till en handlingsinriktad diskurs. Ambitionen är att rikta uppmärksamheten mot den pedagogiska övervägande handlingen genom att pröva konkreta exempel från en pedagogisk praktik mot en begreppsapparat inspirerad av den humanvetenskapliga handlingsteorin. Forskningsfrågorna lyder: Vad är en övervägande handling? Hur byggs den upp och vad förutsätter den? Bakgrunden till intresset att belysa den övervägande handlingen är en önskan att överbrygga klyftan mellan teori och praktik och att hitta ett sätt att samtala om ”tyst kunskap” och den konkreta pedagogiska verkligheten så att denna kan utvecklas på ett meningsfullt sätt. Förhållandet mellan intentionalitet och instrumentella handlingar är av särskilt intresse. Den aristoteliska begreppsapparaten som avser att belysa den mänskliga handlingen används i studien som både utgångspunkt och analysredskap. Retoriken ses som den vetenskap som kan beskriva och förklara hur vi skapar mening med hjälp av språket. Fyra fokussamtal med sammanlagt fem studerande på musikanimatörutbildningen genomfördes under vårterminen 2006. Referaten från samtalen bearbetades till en berättelse. I konstruktionen av berättelsen användes dels en fenomenologisk analys, dels narrativ bearbetning. De aristoteliska begreppen poíesis, praxis och theoria tillämpades och prövades på berättelsen varefter en retorisk analys genomfördes. Berättelsen visar två konkurrerande praxis. Utbildningen framstår i berättelsen dels som en horisontell ”alla kan”-utbildning, dels som en vertikal och lärarstyrd verksamhet. Berättelsen ger inte så många exempel på pedagogiska överväganden men tydliggör ändå den övervägande handlingen. Det pedagogiska övervägandet innebär ett väljande utifrån teoretiskt tänkbara och med praxis förenliga handlingsalternativ. Reflektion ingår i övervägandet men är inte detsamma som övervägande. Övervägandet är inte enbart en rationellt kalkylerande aktivitet. Holistiska och intuitiva procedurer är en viktig del i processen. Övervägande förutsätter dessutom ansvar.