Construção de uma cela de fluxo para medidas por espectrofotometria em fase sólida

A simple and low cost flow cell is proposed for measurements by solid-phase spectrophotometry employing a conventional spectrophotometer. The flow cell geometry allows the employment of a large amount of the solid support without causing both excessive attenuation of the radiation beam and increasing of the back-pressure. The adaptation of the flow cell in the optical path of the spectrophotometer in order to increase the precision is discussed. The flow cell characteristics were demonstrated by measurements of Co(II), employing 1-(2-tiazolylazo)-2-naphthol (TAN) immobilized on C18 bonded silica as solid support. The apparent molar absorptivity and coefficient of variation were estimated as 1.86 x 10(5) L mol-1 cm-1 and 1.4 % (n=15). A sample throughput of 40 determinations per hour and a detection limit of 15 mug L-1 (99.7 % confidence level) were achieved.

A proposta curricular de química do Estado de Minas Gerais: fundamentos e pressupostos

This article presents the basic ideas that oriented the elaboration of the new Chemistry Curriculum for the High Schools in the State of Minas Gerais, Brazil. The main features of traditional Brazilian Chemistry Curriculum are critically discussed, namely, the excessive number of concepts, the overemphasis in procedures and rituals instead of chemical principles and the lack of relationship between the concepts and the social, technological and environmental contexts. Trying to overcome these features, the proposed curriculum deals with a fewer number of concepts, clearly related in a conceptual structure, opening space to a balanced emphasis on phenomena, theory and representation, and on conceptual and contextual aspects of chemical knowledge.

Osakeperusteinen palkitseminen: maksuttoman osakkeen hyödyntäminen kannustinjärjestelmissä

Tutkielman tavoitteena on selvittää osakeyhtiön palkitsemisjärjestelmiin liittyviä kysymyksiä päämies–agenttisuhteiden ja osakeyhtiöoikeudellisten periaatteiden kautta. Tutkielmassa selvitetään, kuinka maksuttomia osakkeita voidaan hyödyntää julkisen osakeyhtiön palkitsemisjärjestelmissä ja mitä haasteita ja mahdollisuuksia niiden käyttöön liittyy. Tutkimusmetodi työssä on lainopillinen ja aihetta lähestytään luontevasti kauppatieteellisen ja oikeustieteellisen näkökulman yhdistävän oikeustaloustieteen kautta. Ensisijaisena aineistona tutkielmassa käytetään voimassaolevaa lainsäädäntöä valmisteluaineistoineen ja näkökulmaa syvennetään aiemmin voimassa olleen lainsäädännön tarkastelulla. Toissijaisena aineistona tutkielmassa käytetään sekä eri asiantuntijoiden oikeudellista kirjallisuutta että palkitsemisen asiantuntijoiden laatimaa kirjallisuutta Suomesta ja muista länsimaista. Teoreettista työtä on syvennetty asiantuntijahaastattelulla ja yhtiöiden sijoittajatiedosta saatavalla informaatiolla. Merkittävin osakeyhtiön johdon ja yhtiön välisen suhteen tehokkuutta alentava seikka on päämies–agenttisuhteen valvontaongelma. Tämä liittyy päämies - agenttisuhteeseen, joka ilmenee negatiivisesti yhtiön ja yhtiön johdon intressien ristiriitatilanteissa. Valvontaongelma voi aiheuttaa ylimääräisiä transaktiokustannuksia ja tämä näkyy yhtiön toiminnan tehokkuuden laskemisena. Päämies–agenttisuhteen ratkaisuna lainsäädäntö ja erilaiset valvonnan keinot ovat tehottomia ja nykyisen yhtiöoikeudellisen ajattelun vastaisia. Tehokkaimmin valvontaongelma saadaan ratkaistua erilaisin kannustimin tapahtuvalla johdon ohjauksella. Osakesidonnainen palkitseminen on suosituin johdon ja yhtiön intressien yhdistämisen keino. Osakesidonnainen palkitseminen on parhaimmillaan eri osapuolien näkökulmasta sitouttavaa ja kannustavaa mutta osakepalkitsemisen käyttöön liittyy myös riskejä. Eräs keskeisistä yhtiöoikeudellisista periaatteista on yhdenvertaisuus, jota saatetaan loukata eri palkitsemisjärjestelmiä käytettäessä. Varojen jakoon ja järjestelmien rahoitukseen liittyy niin ikään riskejä, jotka saattavat vaarantaa järjestelmän onnistumisen. Liian avokätiset palkkiojärjestelmät taas saattavat aiheuttaa yhtiön eri sidosryhmien piirissä tyytymättömyyttä joka taas alentaa järjestelmän tehokkuutta. Yhtiön johto vastaa yhtiön strategian toteutumisesta ja linjaa Corporate Governance käytännön mukaisesti johdon palkitsemisen tavat. Yhtiön johto on kuitenkin päätöksistään vastuussa yhtiön residuaalioikeuden omaaville päämiehille, eli osakkeenomistajille. Vaikka yhtiön johto vastaa viime kädessä yhtiön toiminnasta, sen on huomioitava toiminnassaan yhtiön toiminnan tarkoitus ja sitä kautta yksittäisen osakkeenomistajan etu. Vaikka osakeyhtiössä toteutettaisiin enemmistöomistajan valitsemaa toimintalinjaa, osakeyhtiön yhdenvertaisuusperiaate korostaa juuri vähemmistöosakkeenomistajan asemaa. Johdon fidusiaaristen velvoitteiden voidaankin nähdä korostuvan johdon suhteessa vähemmistöosakkeenomistajaan. Tämä on huomioitava myös palkitsemisjärjestelmissä. Johdon palkitsemisjärjestelmien suunnittelussa ja toteutuksessa on suunnattava keskeinen huomio sen tavoitteiden toteutumiseen, eli yksittäisen osakkeenomistajan omistuksen arvon kasvattamiseen pidemmällä aikavälillä, pitäen huolta osakeyhtiön kantavista periaatteista.

Toward 'Complexics' as a transdiscipline

The proposed transdisciplinary field of ‘complexics’ would bring together allcontemporary efforts in any specific disciplines or by any researchersspecifically devoted to constructing tools, procedures, models and conceptsintended for transversal application that are aimed at understanding andexplaining the most interwoven and dynamic phenomena of reality. Our aimneeds to be, as Morin says, not “to reduce complexity to simplicity, [but] totranslate complexity into theory”.New tools for the conception, apprehension and treatment of the data ofexperience will need to be devised to complement existing ones and toenable us to make headway toward practices that better fit complexictheories. New mathematical and computational contributions have alreadycontinued to grow in number, thanks primarily to scholars in statisticalphysics and computer science, who are now taking an interest in social andeconomic phenomena.Certainly, these methodological innovations put into question and againmake us take note of the excessive separation between the training receivedby researchers in the ‘sciences’ and in the ‘arts’. Closer collaborationbetween these two subsets would, in all likelihood, be much moreenergising and creative than their current mutual distance. Humancomplexics must be seen as multi-methodological, insofar as necessarycombining quantitative-computation methodologies and more qualitativemethodologies aimed at understanding the mental and emotional world ofpeople.In the final analysis, however, models always have a narrative runningbehind them that reflects the attempts of a human being to understand theworld, and models are always interpreted on that basis.

Wine, alcohol, polyphenols and cardiovascular disease

Abstract. Excessive alcohol consumption is associated with increased morbidity and mortality as well as with labour and traffic accidents. However, current evidence suggests beneficial effects of moderate drinking on cardiovascular events including coronary heart disease, ischaemic stroke, peripheral arterial disease and congestive heart failure. The underlying mechanisms to explain these protective effects against coronary heart disease include an increase in high-density lipoprotein cholesterol and an increase in insulin sensitivity, and a decrease in platelet aggregation and circulating concentrations of fibrinogen. However, there are discrepancies regarding the specific effects of different types of beverages on the cardiovascular system, and also whether the possible protective effects of alcoholic beverages are due to their alcohol component (ethanol) or non-alcoholic products containing, mainly polyphenols. Recent randomised clinical trials have shown that wine, a polyphenol-rich alcoholic beverage, provides higher antioxidant and anti-inflammatory effects than some spirits such as gin, a polyphenol-free alcoholic beverage. In addition, dealcoholized red wine decreases blood pressure through a nitric oxide mediated mechanism, suggesting a protective effect of polyphenols on vascular function. Other studies performed in women have observed that daily doses of 1520 g of alcohol as red wine are sufficient to elicit protective effects similar to those observed in men who consumed higher doses of wine. In conclusion, moderate consumption of wine exerts a protective effect on biomarkers related to the progression and development of atherosclerosis due to its alcoholic (ethanol) and non-alcoholic (polyphenols) content. Women are more sensitive to the beneficial effects of wine.

Toward 'Complexics' as a transdiscipline

The proposed transdisciplinary field of ‘complexics’ would bring together allcontemporary efforts in any specific disciplines or by any researchersspecifically devoted to constructing tools, procedures, models and conceptsintended for transversal application that are aimed at understanding andexplaining the most interwoven and dynamic phenomena of reality. Our aimneeds to be, as Morin says, not “to reduce complexity to simplicity, [but] totranslate complexity into theory”.New tools for the conception, apprehension and treatment of the data ofexperience will need to be devised to complement existing ones and toenable us to make headway toward practices that better fit complexictheories. New mathematical and computational contributions have alreadycontinued to grow in number, thanks primarily to scholars in statisticalphysics and computer science, who are now taking an interest in social andeconomic phenomena.Certainly, these methodological innovations put into question and againmake us take note of the excessive separation between the training receivedby researchers in the ‘sciences’ and in the ‘arts’. Closer collaborationbetween these two subsets would, in all likelihood, be much moreenergising and creative than their current mutual distance. Humancomplexics must be seen as multi-methodological, insofar as necessarycombining quantitative-computation methodologies and more qualitativemethodologies aimed at understanding the mental and emotional world ofpeople.In the final analysis, however, models always have a narrative runningbehind them that reflects the attempts of a human being to understand theworld, and models are always interpreted on that basis.

Overvoltage Mitigation Techniques in Wind Power Generators

Advancements in power electronic semiconductor switching devices have lead to significantly faster switching times. In motor and generator applications, the fast switching times of pulse width modulated (PWM) inverters lead to overvoltages caused by voltage reflections with shorter and shorter cables. These excessive overvoltages may lead to a failure of the electrical machine in a matter of months. In this thesis, the causes behind the overvoltage phenomenon as well as its different mitigation techniques are studied. The most suitable techniques for mitigating the overvoltage phenomenon in wind power generator applications are chosen based on both simulations and actual measurements performed on a prototype. An RC filter at the terminals of the electrical machine and an inverter output filter designed to reduce the rise and fall times of voltage pulses are presented as a solution to the overvoltage problem. The performance and losses of both filter types are analysed.

El cuidado de los ancianos en el entorno familiar : valoración de los recursos de apoyo mediante grupos de discusión

Introduction: in the present study several collectives with knowledge of the reality of family care of the elderly assessed several socia and healthcare resources and suggested several possibilities for improvement. Method: four discussion groups were used as a data collection technique. The groups were composed of caregivers, representatives-users of associations for the elderly, experts in geriatrics, and social services professionals. Results: the various discussion groups positively evaluated the Home Help Service, the Support Teams of the Home Service Programs, Interdisciplinary Community Health Workers Units, Daytime Care Centres, and the Family Rest Programme but suggested some changes to all of them. The discussion groups also indicated the need to improve the material, economic and emotional assistance given to caregivers and asked for training, institutional coordination, anddissemination of information about available resources and assistance. Conclusions: some changes are required to improve the current social and health resources available to families caring for the elderly within the family unit. Among the suggestions for improvement proposed by the participants, many are useful and could easily be applied, whereas others provide an interesting starting point for debate and reflection. Knowledge and understanding of the situation of caregiving families, based on their own experiences and those of the people who know them, is in itself sufficient to initiate and implement changes to provide resources appropriate to their needs

The effects of real time control of welding parameters on weld quality in plasma arc keyhole welding

Joints intended for welding frequently show variations in geometry and position, for which it is unfortunately not possible to apply a single set of operating parameters to ensure constant quality. The cause of this difficulty lies in a number of factors, including inaccurate joint preparation and joint fit up, tack welds, as well as thermal distortion of the workpiece. In plasma arc keyhole welding of butt joints, deviations in the gap width may cause weld defects such as an incomplete weld bead, excessive penetration and burn through. Manual adjustment of welding parameters to compensate for variations in the gap width is very difficult, and unsatisfactory weld quality is often obtained. In this study a control system for plasma arc keyhole welding has been developed and used to study the effects of the real time control of welding parameters on gap tolerance during welding of austenitic stainless steel AISI 304L. The welding tests demonstrated the beneficial effect of real time control on weld quality. Compared with welding using constant parameters, the maximum tolerable gap width with an acceptable weld quality was 47% higher when using the real time controlled parameters for a plate thickness of 5 mm. In addition, burn through occurred with significantly larger gap widths when parameters were controlled in real time. Increased gap tolerance enables joints to be prepared and fit up less accurately, saving time and preparation costs for welding. In addition to the control system, a novel technique for back face monitoring is described in this study. The test results showed that the technique could be successfully applied for penetration monitoring when welding non magnetic materials. The results also imply that it is possible to measure the dimensions of the plasma efflux or weld root, and use this information in a feedback control system and, thus, maintain the required weld quality.

Jatkuvatoimisen natriumhypokloriittireaktorin mallinnus

Natriumhypokloriittia voidaan valmistaa kloorista ja lipeästä jatkuvatoimisessa absorberissa. Tässä työssä tutkittiin kokeellisesti, miten kaasun ja nesteen virtausnopeudet vaikuttavat täytekappalekolonnin tulvimiseen ja painehäviöön, kuinka nopeasti kloori absorboituu lipeään ja kuinka suuri hypokloriittiliuoksen kierrätys tarvitaan, ettei hypokloriitti ala hajota. Lisäksi luotiin matemaattinen malli, jolla voidaan mitoittaa jatkuvatoiminen vastavirtaperiaatteella toimiva natriumhypokloriittireaktori. Kloori–lipeäsysteemin havaittiin tulvivan suuremmilla virtausnopeuksilla kuin ilma–vesisysteemin. Tosin osa kloorista absorboituu jo ennen täytekappalekerrosta, minkä vuoksi kaasun todellinen virtausnopeus täytekappalekerroksen alaosassa on pienempi kuin mitattu arvo. Kolonnin painehäviö nousee erittäin jyrkästi tulvimispisteen läheisyydessä. Koska kloori absorboituu lähes täydellisesti ja vain kolonnin alaosa tulvii, voidaan kolonnia painehäviön kannalta operoida lähellä tulvimispistettä. Sekä mallinnuksen että koetulosten perusteella yli 99,99 % kloorista absorboituu koeolosuhteissa kahden metrin täytekappalekerroksessa. Nopea absorptio johtuu erittäin nopeasta, irreversiibelistä kloorin reaktiosta ja prosessille tyypillisestä natriumhydroksidikonversion rajoittamisesta alle 94 %:iin. Jotta varmistetaan, ettei hypokloriitti ala hajota, valmista hypokloriittiliuosta täytyy kierrättää kolonniin vähintään noin 4-kertainen määrä tuoreen lipeän syöttömäärän nähden.

The effect of microfibrillated cellulose addition on drying shrinkage and dimensional stability of wood-free paper

Microfibrillated cellulose (MFC) is known to enhance strength properties of paper. Improved strength usually means increased bonding which is strongly connected to dimensional instability of paper. Dimensional instability is due to changes in moisture content of paper; when paper is moistened it expands and when dried, it shrinks. Hygroexpansion is linked to end-use problems and excessive drying shrinkage consumes strength potential. Effective use of materials requires controlling of these phenomena. There isn’t yet data concerning dimensional stability of papers containing MFC which restricts wider use of MFC. Main objective of the work was to evaluate dimensional stability of wood-free paper containing different amounts of MFC. Sheets were dried with different methods to see how drying strains effected on drying shrinkage and hygroexpansion. Also tensile strength was measured to find out the effect of MFC. Results were compared to sheets containing kraft fines and in some test points cationic starch was used alongside with MFC. MFC increased the dimensional instability of freely dried sheets. As the amounts of MFC increased the effects on dimensional stability became more severe. However the fineness of MFC didn’t play any important role. Both hygroexpansion and drying shrinkage were decreased with cationic starch addition. Prevention of drying shrinkage over powered the effects of additives on hygroexpansion. Tensile strength improved up till 7 % addition amount which could be set as the upper limit of MFC addition when paper preparation and tensile strength are concerned.

Horizontal Grid Size Selection and its Influence on Mesoscale Model Simulations

The use of two-dimensional spectral analysis applied to terrain heights in order to determine characteristic terrain spatial scales and its subsequent use for the objective definition of an adequate grid size required to resolve terrain forcing are presented in this paper. In order to illustrate the influence of grid size, atmospheric flow in a complex terrain area of the Spanish east coast is simulated by the Regional Atmospheric Modeling System (RAMS) mesoscale numerical model using different horizontal grid resolutions. In this area, a grid size of 2 km is required to account for 95% of terrain variance. Comparison among results of the different simulations shows that, although the main wind behavior does not change dramatically, some small-scale features appear when using a resolution of 2 km or finer. Horizontal flow pattern differences are significant both in the nighttime, when terrain forcing is more relevant, and in the daytime, when thermal forcing is dominant. Vertical structures also are investigated, and results show that vertical advection is influenced highly by the horizontal grid size during the daytime period. The turbulent kinetic energy and potential temperature vertical cross sections show substantial differences in the structure of the planetary boundary layer for each model configuration

Moderate-Vigorous physical activity across Body Mass Index in females: moderating effect of endocannabinoids and temperament

Background: Endocannabinoids and temperament traits have been linked to both physical activity and body mass index (BMI) however no study has explored how these factors interact in females. The aims of this cross-sectional study were to 1) examine differences among distinct BMI groups on daytime physical activity and time spent in moderate-vigorous physical activity (MVPA), temperament traits and plasma endocannabinoid concentrations; and 2) explore the association and interaction between MVPA, temperament, endocannabinoids and BMI. Methods: Physical activity was measured with the wrist-worn accelerometer Actiwatch AW7, in a sample of 189 female participants (43 morbid obese, 30 obese, and 116 healthy-weight controls). The Temperament and Character Inventory-Revised questionnaire was used to assess personality traits. BMI was calculated by bioelectrical impedance analysis via the TANITA digital scale. Blood analyses were conducted to measure levels of endocannabinoids and endocannabinoid-related compounds. Path-analysis was performed to examine the association between predictive variables and MVPA. Results: Obese groups showed lower MVPA and dysfunctional temperament traits compared to healthy-weight controls. Plasma concentrations of 2-arachidonoylglyceryl (2-AG) were greater in obese groups. Path-analysis identified a direct effect between greater MVPA and low BMI (b = −0.13, p = .039) and high MVPA levels were associated with elevated anandamide (AEA) levels (b = 0.16, p = .049) and N-oleylethanolamide (OEA) levels (b = 0.22, p = .004), as well as high Novelty seeking (b = 0.18, p<.001) and low Harm avoidance (b = −0.16, p<.001). Conclusions: Obese individuals showed a distinct temperament profile and circulating endocannabinoids compared to controls. Temperament and endocannabinoids may act as moderators of the low MVPA in obesity.

Looking beneath Dalí's paint: non-destructive canvas analysis

A new analytical method was developed to non-destructively determine pH and degree of polymerisation (DP) of cellulose in fibres in 19th 20th century painting canvases, and to identify the fibre type: cotton, linen, hemp, ramie or jute. The method is based on NIR spectroscopy and multivariate data analysis, while for calibration and validation a reference collection of 199 historical canvas samples was used. The reference collection was analysed destructively using microscopy and chemical analytical methods. Partial least squares regression was used to build quantitative methods to determine pH and DP, and linear discriminant analysis was used to determine the fibre type. To interpret the obtained chemical information, an expert assessment panel developed a categorisation system to discriminate between canvases that may not be fit to withstand excessive mechanical stress, e.g. transportation. The limiting DP for this category was found to be 600. With the new method and categorisation system, canvases of 12 Dalí paintings from the Fundació Gala-Salvador Dalí (Figueres, Spain) were non-destructively analysed for pH, DP and fibre type, and their fitness determined, which informs conservation recommendations. The study demonstrates that collection-wide canvas condition surveys can be performed efficiently and non-destructively, which could significantly improve collection management.

Concentrated Winding Multiphase Permanent Magnet Machine Design and Electromagnetic Properties – Case Axial Flux Machine

Concentrated winding permanent magnet machines and their electromagnetic properties are studied in this doctoral thesis. The thesis includes a number of main tasks related to the application of permanent magnets in concentrated winding open slot machines. Suitable analytical methods are required for the first design calculations of a new machine. Concentrated winding machines differ from conventional integral slot winding machines in such a way that adapted analytical calculation methods are needed. A simple analytical model for calculating the concentrated winding axial flux machines is provided. The next three main design tasks are discussed in more detail in the thesis. The magnetic length of the rotor surface magnet machines is studied, and it is shown that the traditional methods have to be modified also in this respect. An important topic in this study has been to evaluate and minimize the rotor permanent magnet Joule losses by using segmented magnets in the calculations and experiments. Determination of the magnetizing and leakage inductances for a concentrated winding machine and the torque production capability of concentrated winding machines with different pole pair numbers are studied, and the results are compared with the corresponding properties of integral slot winding machines. The thesis introduces a new practical permanent magnet motor type for industrial use. The special features of the machine are based on the option of using concentrated winding open slot constructions of permanent magnet synchronous machines in the normal speed ranges of industrial motors, for instance up to 3000 min-1, without excessive rotor losses. By applying the analytical equations and methods introduced in the thesis, a 37 kW 2400 min-1 12-slot 10-pole axial flux machine with rotor-surfacemounted magnets is designed. The performance of the designed motor is determined by experimental measurements and finite element calculations.