Análise de fármacos em material biológico: acoplamento microextração em fase sólida "no tubo" e cromatografia líquida de alta eficiência

A new solid phase microextraction (SPME) system, known as in-tube SPME, was recently developed using an open tubular fused-silica capilary column, instead of an SPME fiber, as the SPME device. On-line in-tube SPME is usually used in combination with high performance liquid chromatography. Drugs in biological samples are directly extracted and concentrated in the stationary phase of capillary columns by repeated draw/eject cycles of sample solution, and then directly transferred to the liquid chromatographic column. In-tube SPME is suitable for automation. Automated sample handling procedures not only shorten the total analysis time, but also usually provide better accuracy and precision relative to manual techniques. In-tube SPME has been demonstrated to be a very effective and highly sensitive technique to determine drugs in biological samples for various purposes such as therapeutic drug monitoring, clinical toxicology, bioavailability and pharmacokinetics.

Determinação de manganês em material particulado atmosférico de ambientes de trabalho utilizando eletrodo de diamante dopado com boro e voltametria de onda quadrada com redissolução catódica

A boron-doped diamond electrode is used for determination of Mn(II) in atmospheric particulate matter by square wave cathodic stripping voltammetry. The analytical curve was linear for Mn(II) concentrations between 5.0 and 37.5 µg L-1, with quantification limit of 3.6 µg L-1. The precision was evaluated by the relative standard deviation, with values between 5.1% and 9.3%. The electrode is free of adsorption, minimizing memory effects. Samples collected in the workplace atmosphere of a foundry had Mn(II) concentrations between 0.4 and 4 µg m-3. No significant differences were observed between the proposed method and inductively coupled plasma optical emission spectroscopy.

Fate of peat utilization

Peat is an organic substance with the maintenance of a mineral part, what shows it as interesting object for studying. Both organic and mineral parts of peat find application in various fields of activity of the people. Antibacterial properties of peat are known since an antiquity. Today people have expanded a spectrum of application of peat to use of by-products of its processing for reception of rather ecologically harmless fuel. The master theses are focused on peat, as on ambiguous raw materials for processing and fuel manufacture. The purpose of theses to show how much widely applied peat, technologies on its processing and its influence on environment at all stages of its working out.

The Effect of Operational Disturbances on Reliability and Operation Time Distribution of NCmachine Tools in FMS

This thesis concentrates on studying the operational disturbance behavior of machine tools integrated into FMS. Operational disturbances are short term failures of machine tools which are especially disruptive to unattended or unmanned operation of FMS. The main objective was to examine the effect of operational disturbances on reliability and operation time distribution for machine tools. The theoretical part of the thesis covers the fimdamentals of FMS relating to the subject of this study. The concept of FMS, its benefits and operator's role in FMS operation are reviewed. The importance of reliability is presented. The terms describing the operation time of machine tools are formed by adopting standards and references. The concept of failure and indicators describing reliability and operational performance for machine tools in FMSs are presented. The empirical part of the thesis describes the research methodology which is a combination of automated (ADC) and manual data collection. By using this methodology it is possible to have a complete view of the operation time distribution for studied machine tools. Data collection was carried out in four FMSs consisting of a total of 17 machine tools. Each FMS's basic features and the signals of ADC are described. The indicators describing the reliability and operation time distribution of machine tools were calculated according to collected data. The results showed that operational disturbances have a significant influence on machine tool reliability and operational performance. On average, an operational disturbance occurs every 8,6 hours of operation time and has a down time of 0,53 hours. Operational disturbances cause a 9,4% loss in operation time which is twice the amount of losses caused by technical failures (4,3%). Operational disturbances have a decreasing influence on the utilization rate. A poor operational disturbance behavior decreases the utilization rate. It was found that the features of a part family to be machined and the method technology related to it are defining the operational disturbance behavior of the machine tool. Main causes for operational disturbances were related to material quality variations, tool maintenance, NC program errors, ATC and machine tool control. Operator's role was emphasized. It was found that failure recording activity of the operators correlates with the utilization rate. The more precisely the operators record the failure, the higher is the utilization rate. Also the FMS organizations which record failures more precisely have fewer operational disturbances.

Water circulations for effective bleaching of high-brightness mechanical pulps

The amount of water available is usually restricted, which leads to a situation where a complete understanding of the process, including water circulations and the influence of water components, is essential. The main aim of this thesis was to clarify the possibilities for the efficient use of residual peroxide by means of water circulation rearrangements. Rearranging water circulations and the reduction of water usage may cause new problems, such as metal induced peroxide decomposition that needs to be addressed. This thesis introduces theoretical methods of water circulations to combine two variables; effective utilization of residual peroxide and avoiding manganese in the alkaline peroxide bleaching stage. Results are mainly based on laboratory and mill site experiments concerning the utilization of residual peroxide. A simulation model (BALAS) was used to evaluate the manganese contents and residual peroxide doses. It was shown that with optimum recirculation of residual peroxide the brightness can be improved or chemical costs can be decreased. From the scientific perspective, it was also very important to discover that recycled peroxide was more effective pre-bleaching agent compared to fresh peroxide. This can be due to the organic acids i.e. per acetic acid in wash press filtrate that have been formed in alkaline bleaching stage. Even short retention time was adequate and the activation of residual peroxide using sodium hydroxide was not necessary. There are several possibilities for using residual peroxide in practice regarding bleaching. A typical modern mechanical pulping process line consist of defibering, screening, a disc filter, a bleach press, high consistency (HC) peroxide bleaching and a wash press. Furthermore there usually is not a particular medium consistency (MC) pre-bleaching stage that includes additional thickening equipment. The most advisable way to utilize residual peroxide in this kind of process is to recycle the wash press filtrate to the dilution of disc filter pulp (low MC pre-bleaching stage). An arrangement such as this would be beneficial in terms of the reduced convection of manganese to the alkaline bleaching stage. Manganese originates from wood material and will be removed to the water phase already in the early stages of the process. Recycling residual peroxide prior to the disc filter is not recommended because of low consistencies. Regarding water circulations, the novel point of view is that, it would be beneficial to divide water circulations into two sections and the critical location for the division is the disc filter. Both of these two sections have their own priority. Section one before the disc filter: manganese removal. Section two after the disc filter: brightening of pulp. This division can be carried out if the disc filter pulp is diluted only by wash press filtrate before the MC storage tower. The situation is even better if there is an additional press after the disc filter, which will improve the consistency of the pulp. This has a significant effect on the peroxide concentration in the MC pre-bleaching stage. In terms of manganese content, it is essential to avoid the use of disc filter filtrate in the bleach press and wash press showers. An additional cut-off press would also be beneficial for manganese removal. As a combination of higher initial brightness and lower manganese content, the typical brightness increase varies between approximately 0.5 and 1% ISO units after the alkaline peroxide bleaching stage. This improvement does not seem to be remarkable, but as it is generally known, the final brightness unit is the most expensive and difficult to achieve. The estimation of cost savings is not unambiguous. For example in GW/TMP mill case 0.6% ISO units higher final brightness gave 10% savings in the costs of bleaching chemicals. With an hypothetical 200 000 ton annual production, this means that the mill could save in the costs of bleaching chemicals more than 400 000 euros per year. In general, it can be said that there were no differences between the behavior of different types of processes (GW, PGW, TMP and BCTMP). The enhancement of recycling gave a similar response in all cases. However, we have to remember that the utilization of residual peroxide in older mills depends a great deal on the process equipment, the amount of water available and existing pipeline connections. In summary, it can be said that processes are individual and the same solutions cannot be applied to all cases.

Non-resorbable glass fibre-reinforced composite with porous surface as bone substitute material: Experimental studies in vitro and in vivo focused on bone-implant interface

The development of load-bearing osseous implant with desired mechanical and surface properties in order to promote incorporation with bone and to eliminate risk of bone resorption and implant failure is a very challenging task. Bone formation and resoption processes depend on the mechanical environment. Certain stress/strain conditions are required to promote new bone growth and to prevent bone mass loss. Conventional metallic implants with high stiffness carry most of the load and the surrounding bone becomes virtually unloaded and inactive. Fibre-reinforced composites offer an interesting alternative to metallic implants, because their mechanical properties can be tailored to be equal to those of bone, by the careful selection of matrix polymer, type of fibres, fibre volume fraction, orientation and length. Successful load transfer at bone-implant interface requires proper fixation between the bone and implant. One promising method to promote fixation is to prepare implants with porous surface. Bone ingrowth into porous surface structure stabilises the system and improves clinical success of the implant. The experimental part of this work was focused on polymethyl methacrylate (PMMA) -based composites with dense load-bearing core and porous surface. Three-dimensionally randomly orientated chopped glass fibres were used to reinforce the composite. A method to fabricate those composites was developed by a solvent treatment technique and some characterisations concerning the functionality of the surface structure were made in vitro and in vivo. Scanning electron microscope observations revealed that the pore size and interconnective porous architecture of the surface layer of the fibre-reinforced composite (FRC) could be optimal for bone ingrowth. Microhardness measurements showed that the solvent treatment did not have an effect on the mechanical properties of the load-bearing core. A push-out test, using dental stone as a bone model material, revealed that short glass fibre-reinforced porous surface layer is strong enough to carry load. Unreacted monomers can cause the chemical necrosis of the tissue, but the levels of leachable resisidual monomers were considerably lower than those found in chemically cured fibre-reinforced dentures and in modified acrylic bone cements. Animal experiments proved that surface porous FRC implant can enhance fixation between bone and FRC. New bone ingrowth into the pores was detected and strong interlocking between bone and the implant was achieved.

Composição elementar do material particulado presente no aerossol atmosférico do município de Sete Lagoas, Minas Gerais

The main objective of this study was the identification of sources generating particulate matter in the atmospheric aerosols of Sete Lagoas, Minas Gerais. The measurement of the mineral composition was accomplished by X-ray diffractometry and the elemental concentration by neutron activation analysis. The results showed that Al, Cl, Cu, Fe, K, Mg and Na are the predominant chemical elements in the total suspended particles (TPS). The presence of Na, Ba, Cl, Cu, Eu, Fe and Sm in those particles with aerodynamic diameter smaller than 10 µm (PM10), indicates that soil dust and ceramic and pig iron industries are the main sources of air quality degradation in the region.

Hemicellulose extracted Kraft pulp as a raw material of paper

The transformation of a traditional pulp mill into an integrated forest biorefinery utilizing wood-derived biomass presents a promising opportunity for enterprise revival of the pulp and paper industry by offering new sources of revenue and significantly improved industry profitability. One proposed next generation process step for an integrated forest biorefinery is the extraction of hemicelluloses, allowing the co-production of pulp and ethanol or chemicals. The extraction of hemicelluloses, however, will likely have downstream effects on pulp quality. In the literature survey an overview of the integrated forest biorefinery and possible next generation technologies implementable in such facility were reviewed. Moreover, some hemicellulose extraction methods suitable for the co-production of pulp and hemicellulose products were looked into in more detail. Also, an overview on the significance of pulp’s hemicellulose content on papermaking properties of pulp fibers was made. In the literature it is stated that the hemicellulose content of pulp affects on many papermaking properties of pulp fibers, hornification and paper strength properties in particular. In the experimental part the goal was to investigate what effects alkaline hemicellulose extraction after bleaching has on the papermaking properties of birch Kraft pulp. It was discovered that tested pulps, normal and hemi-poor birch Kraft pulp, were different in many ways regarding to pulp properties. Differences were observed in both physical and chemical characteristics. Furthermore, clear distinctions were seen in tested paper properties, especially in strength properties, between the handsheets made from hemi-poor or normal birch Kraft pulp. Hemi-poor and normal birch Kraft pulps were also compared as a raw material of laboratory made copy paper. Based on this comparison, usage of hemi-poor birch pulp as the raw material of copy paper does not drastically deteriorate its quality.

Analyzing the Background Information of an Activity-Based Costing System

The aim of this thesis was to analyze the background information of an activity-based costing system, which is being used in a domestic forest industry company. The reports produced by the system have not been reliable, and this has caused the utilization of the system to diminish. The study was initiated by examining the theory of activity-based costing. It was also discovered, that the system produces management accounting information and therefore also that theory was introduced briefly. Next the possible sources of errors were examined. The significance of these errors was evaluated and waste handling was chosen as a subject of further study. The problem regarding waste handling was that there is no waste compensation in current model. When paper or board machine produces waste, it can be used as raw material in the process. However, at the moment the product, which is being produced, at the time does not get any compensation. The use of compensation has not been possible due to not knowing the quantity of process waste. As a result of the study a calculatory model, which enables calculating the quantity of process waste based on the data from the mill system, was introduced. This, for one, enables starting to use waste compensation in the future.

A espectrometria atômica e a determinação de elementos metálicos em material polimérico

Polymeric materials are widely used in the chemical industry and are part of our daily lives. Inorganic species may be added to them as additives, anti-oxidizing agents, stabilizers, plasticizers, colorants and catalysts and may be present in a wide range of concentrations. Their determination demands the development of analytical methods considering different kinds of polymeric materials, their composition and the final use of the material. Although many different analytical techniques may be used, this review emphasizes those based on atomic absorption and emission spectrometry. Solid sampling techniques and digestion methods are described and discussed and compared considering published results.

Material per a l'alumnat: Activitats competencials per aprendre a usar les matemàtiques al cicle inicial

Propostes de treball i activitats competencials per aprendre a usar les matemàtiques al CI

Material per a l'alumnat: Aprenem a jugar a escacs (primera part)

Presentació de diferent propostes de treball per a l'alumnat de primària per aprendre a jugar als escacs

Amostragem do material particulado e fração orgânica volátil das emissões em motor ciclo diesel sem a utilização de túnel de diluição

Using a sampling method of particulate matter (PM) without the use of a dilution tunnel allows for evaluations of the volatile hydrocarbons (HC) in the emissions of diesel cycle engines. The procedure in this work applied a heated filter with temperature controlled. The volatile compounds are condensed at low temperature, allowing for evaluation of the HC by thermal desorption of the PM and for analysis of the condensed compounds of the exhaust gases.

Propriedades redox da matéria orgânica isolada de material ultrafiltrado das águas do rio Paraíba do Sul

Previous studies indicated that free radicals control organic matter redox activities. In the present study, organic matter of an ultra-filtrated material collected from seven samples taken seasonally from the Paraiba do Sul River for two years were titrated with an oxidizer (I2) in an inert atmosphere. Standard formal potential values for the electrode MO Ox, MO Red ranged from 0.754 to 0.786 V at a 25 ºC temperature. Organic matter oxidation capacity (COx) per carbon mass varied according to pH values, and changes in COx were related to rainfall and river flow intensities.

Hidrólise parcial da superfície do polyethylene terephthalate (PET): transformando um rejeito em um material de troca catiônica para aplicação ambiental

In this work it is proposed a simple and versatile undergraduate chemical experiment in polymer and environmental technology based on the process of polyethylene terephthalate (PET) hydrolysis. Polyethylene terephthalate from post-consume bottles is submitted to a controlled partial hydrolysis which allows the students to follow the reaction by a simple procedure. The students can explore the reaction kinetics, the effect of catalysts and the exposed polyethylene terephthalate surface area on the hydrolysis reaction. The second and innovative part of this experiment is the technological and environmental application of the hydrolyzed polyethylene terephthalate as a material with cation exchange properties. The surface hydrolyzed polyethylene terephthalate can be used as adsorbent for cationic contaminants.