Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-11-14T13:00:58Z No. of bitstreams: 1 PDF - Bismark Abeku Nyamekye Kushiator.pdf: 1029542 bytes, checksum: 85fec38cb146fdae2ce891a5cb865616 (MD5) / Made available in DSpace on 2017-11-14T13:00:58Z (GMT). No. of bitstreams: 1 PDF - Bismark Abeku Nyamekye Kushiator.pdf: 1029542 bytes, checksum: 85fec38cb146fdae2ce891a5cb865616 (MD5) Previous issue date: 2017-05-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Atmospheric airglow measurements obtained by means of a multichannel photometer in the equatorial region of São João do Cariri, Brazil (7.4 ºS, 36.5 ºO) was used to identify and characterize variations associated with lunar tide. The solar time luminescence data of the three emissions; OH (6, 2), O155577 and 𝑂2(0−1) were smoothed with an average of three months to represent one month in order to reduce variability. The three emissions were subjected to spectral analysis using the Lomb-Scargle peridogram to identify the presence of tidal periodicities of each emission of airglow. The residual from each emission were obtained as a result of the subtraction of the reconstructed composite day using the components diurna, semidiurna and terdiuna of the solar tide, for each three months of measurements were used. This elimination of solar tide signals produced residual emissions of each data that are converted to lunar time and subjected to harmonic analysis to obtain the monthly amplitudes and phases of the lunar semidiurnal component for each of the three emissions. The time series obtained on a composite lunar day shows the lunar component. From the analysis of the data it was possible to identify the signature of the semidiurnal lunar tide in each emission throughout the year of 2004 in the equatorial region. / Medidas da luminescência atmosférica obtidas através de fotômetro multicanal na região equatorial em São João do Cariri, Brasil (7,4 ºS; 36,5ºO) são usadas para identificar e caracterizar variações associadas à maré lunar. Os dados de luminescência de tempo solar das três emissões; OH (6, 2), OI5577 e 𝑂2 (0- 1) foram suavizados com uma média de três meses para representar um mês, a fim de reduzir a variabilidade. As três emissões foram submetidas a análise espectral utilizando o peridograma de Lomb-Scargle para identificar a presença das periodicidades das marés em cada emissão de luminescência. Os resíduos de cada emissão foram obtidos como resultado da subtração do dia composto reconstruído utilizando as componentes diurna, semidiurna e terdiuna da maré solar. Para isto, foram utilizados três meses de medidas. Esta eliminação de sinais de maré solar produze emissões residuais de cada dado que são convertidas para o tempo lunar e submetidas a análises harmônicas para obter as amplitudes e fases mensais da componente semidiurna lunar para cada uma das três emissões. As séries temporais obtidas em um dia lunar composto mostra o componente lunar. A partir da análise dos dados foi possível identificar a assinatura da maré lunar semidiurna em cada emissão ao longo do ano de 2004 na região equatorial.

The theses compares analytical methods according to current norms used in the Czech Republic to the methods based on the principle according to US EPA. A new device the automatic photometer Aquakem 250 makes use of the US EPA methods. Prior to its laboratory use in the Institute of Public Health in the town of Ostrava the photometer had to be validated. For the comparsion of the analytical methods ion chromatographic, isotachophoresis, spectrophotometric,titrimetric methods were used. The validation process, which was documented (in validation protocols), was time consuming and technically challenging. It was confirmed that the new Aquakem 250 analyzer provides result that are verified by methods which are in accordance with norms applicable in the Czech Republic. After a successful completion of validation and obtained accreditation the new automatic analyzer was put into regular operation in the chemically laboratory.

A method to calculate the Stokes parameters Q, U, as well as angle of polarization (AoP) from the new generation CIMEL Dual-Polar sun/sky radiometer CE318-DP polarized skylight measurements is developed in this thesis. Besides the degree of linear polarization (DoLP) and the total radiance I, the parameters Q, U, and AoP have much potential to improve retrievals of aerosol microphysical and chemical properties. However, they have not been derived based on the CE318-DP so far because they change with the reference plane that is hard to know due to an uncontrolled initial angle related to installation of the optical sensor head to the automated mount of this type of instrument. In this work, the polarization pattern of skylight with the direction of polarization perpendicular to the scattering plane (i.e., the principal plane in the solar principal plane geometry) is applied to correct the initial angle and then to obtained Q, U, and AoP. The perpendicular and parallel polarized radiances Ir and Il, as well as the linear depolarization ratio ρ are further derived after Q is known. A new polarized almucantar geometry based on CE318-DP is measured to illustrate abundant variation features of these parameters. These new polarization parameters in conjunction with DoLP and I are analyzed based on some typical long-term sites within the Sun/sky-radiometer Observation NETwork (SONET) and a joint site of the AErosol RObotic NETwork (AERONET) in China. Results calculated in this work are consistent with previous results, and generally comparable with the vector radiative transfer simulations and the measurements by other polarimetric instrument. Considering a 1°discrepancy of AoP, 3% fractional uncertainty in I and 0.005 uncertainty in DoLP propagated to Q and U, the uncertainties of Q in both of solar principal and almucantar planes and that of U in the almucantar geometry are acceptable.

Made available in DSpace on 2015-05-14T13:21:46Z (GMT). No. of bitstreams: 1 parte1.pdf: 2204692 bytes, checksum: df26e8eadaeacfb0702b39229f465ea2 (MD5) Previous issue date: 2010-03-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work describes the construction of a new flow-batch analyzer (FB) in micro scale (micro Flow-Batch-μFBA) using the technique of deep ultraviolet photolithography with commercial resin based in urethane acrylate oligomers (UA). The device was constructed from the union of two layers of pre-polymerized resin of 3.4 mm thick each, thus forming a single structure. The main feature of the new device is the small volume of its analysis chamber, which can be 100-200 μL, allowing the homogenization of reagent solutions in a time of 2.s. In this sense, the decrease in reagents consumption and hence generation of waste (ten times smaller than a conventional FB), wich is in line with the requirements of green chemistry and with the new position of the eco-efficiency. The system offers the following progress in relation to micro fabrication with urethane acrylate resin: (i) depth control of the channels during photolithography; (ii) axial mixer incorporated; (iii) LED - Light emitting diode (530 nm) and detector (photodiode) coupled to the device body; The depth control of the channels allows adjustment of the volume of the chamber and the LED to the mixing chamber. The LED and detector connector pins is the elements that makes the device fixed on its box. In this first assembly, system were used in photometric determination of Fe (II) in pharmaceuticals. The model for the calibration curve was validated by analysis of variance (ANOVA), and their analytical results were compared with those obtained in batch by the reference method, the application of paired t-test found no statistically significant differences at a confidence level of 95%. / No presente trabalho é descrita a construção de um novo analisador Flow- Batch (FB) em escala micro (micro Flow-Batch - μFBA) utilizando a técnica de fotolitografia profunda no ultravioleta com resina comercial à base de oligômeros uretano e acrilato (UA). O dispositivo foi construído a partir da união de duas camadas da resina pré-polimerizada de 3,4 mm de espessura cada uma, formando assim uma estrutura única. A característica principal do novo dispositivo é o pequeno volume da câmara de análise, que pode ser de 100 a 200 μL, permitindo a homogeneização das soluções reagentes em um tempo de 2.s. Nesse sentido, a diminuição do consumo de reagentes e, conseqüentemente, de resíduos gerados (dez vezes menor que um FB convencional), apontam na direção dos requisitos da química verde e se alinham com a nova postura da ecoeficiência. O sistema apresenta os seguintes avanços em relação à microfabricação com resina uretanoacrilato: (i) controle da profundidade dos canais durante a fotolitografia; (ii) agitador do tipo axial incorporado; (iii) LED emissor de luz (530nm) e detector (fotodiodo) acoplados ao corpo do dispositivo. O controle da profundidade permitiu o ajuste do volume da câmara e do LED à câmara de mistura. Os próprios pinos conectores do LED e do detector foram utilizados como elementos de fixação da peça em sua caixa. Nesta primeira montagem, o sistema foi empregado na determinação fotométrica de Fe (II) em medicamentos. O modelo para a curva de calibração foi validado através da Análise de Variância (ANOVA), e seus resultados analíticos foram comparados com aqueles obtidos em análises de referência através da aplicação do teste-t emparelhado, não apresentando diferenças estatísticas significativas a um nível de confiança de 95%.

Coastal zones receive massive terrestrial inputs of nutrients and organic matter, and play an important role in biogeochemical cycles. The interactions of river inputs, ocean currents, atmospheric exchanges, anthropogenic influences, and biologically active ecosystems make CO2 system studies in coastal waters highly challenging. This work focuses on improving our understanding of the CO2 system in coastal waters through (1) development of a new methodology for measurements of CO2 system parameters in the field; (2) observations of large spatial and temporal CO2 system variations in coastal waters; and (3) characterization of the influence of organics on CO2 system behavior in coastal waters. A novel portable light-emitting-diode (LED) photometer was developed to provide low-cost seawater pH measurements in the field. With meta cresol purple (mCP) as the indicator, the photometer produces pHT measurements within ± 0.01 units of state-of-the-art spectrophotometric measurements (7.6 ≤ pH ≤ 8.2, 30 ≤ S ≤ 36.2, and 15 oC ≤ t ≤ 30 oC). With a simple “do-it-yourself” (DIY) construction design, a hundredfold reduction in cost relative to benchtop spectrophotometric systems, and routine calibration-free operation in the field, the DIY photometer is an ideal replacement for pH test strips or consumer-level potentiometric probes. Applications of special interest include education, citizen science, coastal zone monitoring, and aquaculture and aquarium management. Subannual variability of total alkalinity (TA) distributions in the northeastern Gulf of Mexico (GOM) was examined through the use of TA data from ship-based water sampling, historical records of riverine TA, and contemporaneous model output of surface currents and salinity. Variability of TA observed in the upper 150 m of the GOM water column was primarily controlled by subannual variations in the extent of mixing between seawater and river water. A transition in TA distribution patterns between the river-dominated northern margin (near the Mississippi–Atchafalaya River System) and the ocean current-dominated eastern margin (West Florida Shelf) was observed. A riverine alkalinity input index was developed to highlight riverine TA contributions. Contributions of organic alkalinity (Org-Alk) to TA were investigated in coastal waters from three different environments (estuary, urban, mangrove) and offshore sites in the Gulf of Mexico. The difference in alkalinity (∆TA) between TA measured by direct titration (TAmeas) and calculated (TAcal) from observations of DIC and pH was used as an estimate of Org-Alk. Average values of ∆TA were 0.1 ± 5.0 µmol kg-1 at coastal sample sites outside the Mississippi-Atchafalaya River Estuary (n = 17), 1.9 ± 5.2 µmol kg-1 in offshore waters (n = 14) in the northern Gulf of Mexico, 33.6 ± 18.0 µmol kg-1 in the Suwannee River Estuary (n = 17), and 16.0 ± 25.4 µmol kg-1 in sites that included Tampa Bay, the Caloosahatchee River, and the Ten Thousand Islands area (n = 55). In addition to Org-Alk assessments based on measurements of ∆TA, a novel two-step spectophotometric titration method was developed for the characterization of Org-Alk. Direct titrations showed substantial Org-Alk in coastal samples (n = 5), and the Org-Alk values obtained from the two-step titrations showed good agreement with results from ∆TA calculations. The spectrophotometric titration data were used in model fits to evaluate the dissociation constants (pKi) of the natural organic acids. The pKi of the organic acids were within the previously reported range for riverine fulvic acids.

O ferro é o elemento mais abundante na Terra e tem importante papel em ciclos biogeoquímicos Neste trabalho foi desenvolvido um procedimento analítico automático para a determinação fotométrica de ferro em águas de rios, empregando um fotômetro baseado em LED e mini-bombas solenoide para o gerenciamento de soluções. O procedimento proposto foi baseado na reação do ferro (III) com o tiocianato de potássio formando um complexo avermelhado com máximo de absorção em 470 nm. Para a determinação de ferro total foi incluída uma etapa de oxidação em linha, usando uma solução de persulfato (S2O82-) como oxidante. O módulo de análises foi constituído por quatro mini-bombas solenoide e uma válvula solenoide de três vias. Para a obtenção de sinais foi construído um fotômetro composto por uma cela de fluxo com caminho óptico de 50 mm, um LED azul (\'lâmbda\'=470 nm) e um fotodetector. Visando utilizar este equipamento portátil para medidas em campo, foram empregadas duas baterias de 6 V para alimentar os dispositivos ativos. Os ensaios em laboratório mostraram que as baterias permitem uma autonomia de mais de 50 horas de trabalho sem recarregá-las. O procedimento desenvolvido apresentou as seguintes características analíticas: resposta linear entre as concentrações de 0,25 e 4,0 mg L-1, segundo a equação Y = (0,0183 ± 0,003) + (0,15326 ± 0,002)X (r=0,9997); limite de detecção 0,013 mg L-1 Fe (III) estimado com 99,7 % de confiança; desvio padrão relativo estimado em 0,95 % (n=15) obtido com uma solução de concentração de 1,5 mg L-1 Fe (III); frequência de amostragem de 50 determinações por hora. Os resultados obtidos pelo procedimento proposto e pelo de referência não apresentaram diferenças significativas com nível de confiança de 95 % / Iron is the most abundant element on Earth and plays an important role in biogeochemical cycles. In this work, an automatic analytical procedure was developed for the photometric determination of iron in river waters, employing a LED-based photometer and solenoid mini-pumps for solution handling. The proposed procedure was based on the reaction between iron (III) and potassium thiocyanate, yielding a red complex with maximum absorption at 470 nm. For the determination of total iron, an in line oxidation step was included, employing a persulfate solution (S2O82-) as oxidant. The module was constructed with four solenoid mini-pumps and a three-way solenoid valve. For data acquisition a photometer was constructed with a 50 mm optical path flow cell, a blue LED (\'lâmbda\'= 470 nm) and a photodetector. Envisioning the use of this portable equipment in field, two 6-Volt batteries were employed to supply energy to the active devices. Laboratory tests showed that the batteries provide more than 50 hours of operation without recharging. The proposed procedure showed the following analytical features: linear response between 0.25 and 4.0 mg L-1, according to the equation Y = (0.0183 ± 0.003) + (0.15326 ± 0.002) X (r = 0.9997); detection limit of 0.013 mg L-1 Fe (III), estimated with 99.7 % of confidence; relative standard deviation estimated as 0.95% (n = 15), obtained with a 1.5 mg L-1 Fe (III) solution; sampling rate of 50 determinations per hour.The results obtained with the proposed and reference procedure did not show significative differences at a 95% confidence level

Esta tese tem como foco o desenvolvimento de procedimentos analíticos automáticos, visando as determinações fotométricas de vanádio e de estanho em águas e em alimentos empregando o processo de multicomutação em fluxo. Um microcontrolador da família PIC e um programa escrito em linguagem Visual Basic 6.0 foram empregados para controle dos dispositivos e aquisição de dados. A unidade de detecção foi construída empregando LED de alto brilho e celas de fluxo com longo caminho óptico (50-200 mm) para ganho em sensibilidade. O módulo de análises, empregando bombas solenoide como propulsores de fluido e o fotômetro foram integrados, formando uma unidade compacta. A determinação de vanádio em águas, mineral e de rio, foi baseada na redução do V(V) à V(IV) com ácido ascórbico e posterior complexação com Eriocromo Cianina R (ECR). Empregando uma cela de 150 mm, o sistema apresentou resposta linear de 0,02 a 1,00 mg L-1, limite de detecção estimado em 13 ?g L-1, coeficiente de variação de 0,87% (n=10) e frequência analítica de 47 determinações por hora. Recuperações entre 89 e 109% foram obtidas para adição de V(V) nas amostras de águas. O procedimento para a determinação de estanho em alimentos foi desenvolvido empregando bomba de multi-seringa como unidade de propulsão de fluidos, cela de fluxo com caminho óptico de 200 mm e parada de fluxo de 50 s. Baseado na reação do Sn(IV) com o violeta de pirocatecol (PCV) na presença de surfactantes, o sistema apresentou resposta linear de 0,10 a 1,25 mg L-1, limite de detecção estimado em 0,04 mg L-1, coeficiente de variação de 1,30% (n=10) e frequência analítica de 49 determinações por hora. Recuperações entre 95 e 115% foram obtidas com a adição de Sn(IV) às amostras de alimentos. / Automatic analytical procedures for photometric determinations of vanadium in water and tin in foods were developed using the multicommutation flow analysis process. A microcontroller of the PIC family and a software written in Visual Basic 6.0 language were used for devices control and data acquisition. Detection unit was designed to use high brightness LED and long optical pathlength flow cells (50-200 mm) to improve sensitivity. The flow analysis module using solenoid mini-pumps as fluid propelling devices and the photometer were integrated in order to form a compact unit. The determination of vanadium in mineral and river waters was based on the reduction of V(V) to V(IV) with ascorbic acid and subsequent complexation with Eriochrome Cyanine R (ECR). Employing flow cell of 150 mm, the system presented linear response between 0.02 and 1.00 mg L-1, detection limit of 13 ?g L-1, variation coefficient of 0.87% (n=10) and sampling throughput of 47 determinations per hour. Recoveries between 89 and 109% were attained for vanadium spiked to mineral and river water. The procedure for determination of tin in foods was development employing a multi-syringe pump as fluid propelling device, a flow cell with optical pathlength of 200 mm and stop flow of 50 s. The procedure was based on the reaction of Sn(IV) with pyrocatechol violet (PCV) in the presence of surfactants, presented linear response between 0.10 and 1.25 mg L-1, detection limit of 0.04 mg L-1, variation coefficient of 1.30% (n=10) and sampling throughput of 49 determination per hour. Recoveries between 95 and 115% were attained for tin spiked samples

Aerosols contribute the largest uncertainty to estimates of radiative forcing of the Earth’s atmosphere, which are thought to exert a net negative radiative forcing, offsetting a potentially significant but poorly constrained fraction of the positive radiative forcing associated with greenhouse gases. Aerosols perturb the Earth’s radiative balance directly by absorbing and scattering radiation and indirectly by acting as cloud condensation nuclei, altering cloud albedo and potentially cloud lifetime. One of the major factors governing the uncertainty in estimates of aerosol direct radiative forcing is the poorly constrained aerosol single scattering albedo, which is the ratio of the aerosol scattering to extinction. In this thesis, I describe a new instrument for the measurement of aerosol optical properties using photoacoustic and cavity ring-down spectroscopy. Characterisation is performed by assessing the instrument minimum sensitivity and accuracy as well as verifying the accuracy of its calibration procedure. The instrument and calibration accuracies are assessed by comparing modelled to measured optical properties of well-characterised laboratory-generated aerosol. I then examine biases in traditional, filter-based absorption measurements by comparing to photoacoustic spectrometer absorption measurements for a range of aerosol sources at multiple wavelengths. Filter-based measurements consistently overestimate absorption although the bias magnitude is strongly source-dependent. Biases are consistently lowest when an advanced correction scheme is applied, irrespective of wavelength or aerosol source. Lastly, I assess the sensitivity of the direct radiative effect of biomass burning aerosols to aerosol and cloud optical properties over the Southeast Atlantic Ocean using a combination of offline radiative transfer modelling, satellite observations and global climate model simulations. Although the direct radiative effect depends on aerosol and cloud optical properties in a non-linear way, it appears to be only weakly dependent on sub-grid variability.

This study quantifies discolouration on the surface of Pinus radiata boards during kiln drying, particularly kiln brown stain (KBS), and models it as a function of chemical compounds present in the wood closest to the surface. The discolouration was investigated with two experimental factors: drying time, which consisted in drying at 70/120 ℃ for 0, 8, 16 and 24 hours; and leaching, done at three levels, noleaching, mild and severe, to reduce the soluble compounds present in wood suspected of developing coloured compounds. The colour change was quantified using a reflectance photometer (colour system CIE Yxy, brightness) and by the analysis of digital photographs (colour system CIE Lab). The chemical analysis of the wood closest to the surface of the boards determined fructose, glucose, sucrose (HPLC), total sugar (sum of fructose, glucose and sucrose), total nitrogen (combustion gas analysis), and phenols discriminated by molecular weight (Folin-Ciocalteu method). In the cause-effect analysis, colour was the dependent variable, and drying time and the determinations of chemical compounds were independent variables. After statistical analysis (ANOVA and MANOVA) the dependent variables to be included in the models were luminance factor (Y), brightness (R457 and the blue-to-yellow scale of CIE Lab (b); and the independent variables were drying time, nitrogen, total sugar, and high-molecular-weight phenols. Linear (multivariate regression) and non-linear models (Neural Networks) showed that discolouration during kiln drying was best predicted when the luminance factor (Y) was used to quantify colour change as a function of the content of nitrogen-containing compounds and drying time. Furthermore, the data were fitted into an empirical model based on simple reaction kinetics that considered the rate of discolouration as a function of nitrogen concentration. The results suggest that nitrogen could act as a limiting reactant in Maillard-type reactions that produce colour during kiln drying.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-05-03T13:34:32Z No. of bitstreams: 1 arquivo total.pdf: 3707373 bytes, checksum: bd34d34553cf7afe6f47457ea76d0a05 (MD5) / Made available in DSpace on 2016-05-03T13:34:32Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 3707373 bytes, checksum: bd34d34553cf7afe6f47457ea76d0a05 (MD5) Previous issue date: 2014-03-06 / Commercial flame photometers require a dedicated gas system and have considerable mass and volume, i. e., they are not portable. This work, as such, proposes the development of a portable flame photometer (prototype) using a torch lighter as the atomizer and controller, with an internal gas supply system, and managed by an Android mobile device. The internal control of prototype and the signal processing were performed by an Arduino Uno single-board microcontroller. The Android application was developed in App Inventor, an open source integrated development environment created and maintained by Massachusetts Institute of Technology. The nebulization was accomplished by ultrasonic cavitation in an adapted low power humidifier, which produces an aerosol sample which consists of very small radii droplets. The initiallyturbulent aerosol flow, needed to be damped before it reached the flame. Initial testswith calibration solutions of K+ resulted in a calibration curve validated using analysis of variance, the limits of detection and quantification were estimated. Optimizations still need to be made in the nebulization and aerosol transport system to improve theefficiency and to minimize inter-contamination of samples during the measurements. / Os fotômetros de chama comerciais necessitam de um sistema de gases dedicado e possuem massa e volume consideráveis, ou seja, não são portáteis. O presente trabalho, diante do exposto, propõe-se a mostrar o desenvolvimento de um protótipo de fotômetro de chama portátil pelo uso de um isqueiro maçarico como atomizador, com sistema de alimentação de gases interno e gerenciado por um dispositivo móvel Android. O controle interno do protótipo bem como o processamento de sinal foram realizados por um Arduino Uno. Um aplicativo para o dispositivo móvel foi desenvolvido no App Inventor, ambiente de programação criado e mantido pelo Instituto de Tecnologia de Massachusetts. A nebulização se deu por cavitação ultrassônica em um humidificador de baixa potência o qual produz um aerossol de amostra constituído por gotículas de raio muito pequeno. O fluxo de aerossol inicialmente turbulento precisou ser amortecido antes de sua introdução no queimador. Testes iniciais com soluções de calibração de K+ resultaram numa curva analítica validada utilizando-se a Análise de Variância e os limites de detecção e de quantificação foram determinados. No entanto otimizações ainda precisam ser feitas no sistema de nebulização e transporte de aerossol para a melhoria de sua eficiência e para a minimização de intercontaminação de amostras durante as medidas.