Magister Pharmaceuticae - MPharm / Leonotis leonurus, a South African indigenous medicinal plant, is frequently used in the form of a tea. However, this dosage form has many disadvantages. Consequently three L. leonurus solid extract preparations were prepared and explored as possible replacements of the tea form, but very little was known about their physical and chemical stability during storage. The specific objectives were to: (i) prepare a freeze dried aqueous extract (FDAE), 20 % aqueous ethanol (Aq EtOH) extract and calcium alginate beads of the FDAE form of L. leonurus, (ii) characterize the extracts using parameters of select physical and chemical features and, (iii) determine the long-term stability of the extracts. It was hypothesised that the Aq EtOH extract would contain higher levels of chemical marker compounds (marrubiin and leonurine) than the FDAE and calcium alginate FDAE beads of L. leonurus and, that the calcium alginate FDAE beads would have greater stability (i.e. longer shelf-life) than the FDAE and the Aq EtOH extract. The three L. leonurus solid extracts were prepared using accepted published methods. For the physical characterization of the extracts, the organoleptic properties were determined using the natural senses (e.g. sight, smell, taste, etc.) and for chemical characterization, total phenol content (TPC; using the Folin-Ciocalteu reagent method), total flavonoid content (TFC; using aluminium chloride-methanol solution) and antioxidant activity (using the -diphenyl-2-picryl-hydrazyl (DPPH) assay). To establish the long-term stability of the preparations, encapsulated L. leonurus solid extracts was stored in sealed standard plastic containers at four conditions: (A), room temperature of 24 ˚C ± 5 ˚C; (B), fixed temperature of 30˚C ± 5 ˚C and (C), elevated temperature of 40˚C ± 5 ˚C for 6 months, and (D), accelerated stability test conditions of 40˚C ± 5 ˚C / 75 % RH for 4 weeks. Samples of the stored encapsulated preparations were collected periodically and assessed for changes in organoleptic properties, TPC, TFC, antioxidant activity levels and marker compound (i.e. marrubiin and leonurine) levels. The latter was determined by validated HPLC assay. Yields of 19.9, 12.82 and 10.7 % of FDAE, Aq EtOH extract and calcium alginate FDAE beads were obtained, respectively. Physically the calcium alginate beads contained less moisture (1.86 %) than the FDAE (3.77 %) and Aq EtOH (2.91 %). Chemically the FDAE, Aq EtOH extract and calcium alginate FDAE beads respectively had appreciable and similar TPC (i.e.7.86, 7.52 &, 6.94 mg GAE/g; p > 0.05; Anova) and TFC (i.e. 4.30, 4.47 & 3.67 mg QE/g; p > 0.05; Anova) levels, but variable amounts of marrubiin (i.e. 22.5, 17.5, and 0.4 ug/mg plant extract) and leonurine (i.e. 2.0, 1.4 and 0.7 ug/mg plant extract), respectively. The antioxidant activity levels were also different i.e. EC50 values of 7.71, 6.66 and 11.53 mg/mL (student t-test p-value of < 0.0001; ANOVA-test; p< 0.05) for the FDAE, Aq EtOH extract and calcium alginate FDAE beads, respectively. During storage (i.e. stability study) the L. leonurus solid extracts generally remained physically unaffected by temperature (i.e. no significant change in organoleptic features), but when exposed to humidity the FDAE and Aq EtOH extracts showed clear signs of physical degradation i.e. changed from being flaky powders to sticky melted masses, while the calcium alginate beads remained unchanged. Within 1 month storage at RT, 30 °C, 40 °C and 1 week at 40 °C / 75 % RH the TPC of the encapsulated FDAE decreased significantly by 61, 60, 58 and 52 %, respectively, that for the encapsulated Aq EtOH extract by 61, 54, 46 and 50 %, respectively, and for calcium alginate FDAE beads by 66, 71, 59 and 57 %, respectively. Using TPC as a stability parameter all three encapsulated extracts had very short shelf-lives ranging from 1.24 weeks (0.31 months) to 3.72 weeks (0.93 months). Under the same conditions and storage periods (i.e. 1 month & 1 week) the TFC of the encapsulated FDAE decreased significantly by 25, 25, 29 and 66 %, respectively, for encapsulated Aq EtOH extract by 26, 26, 23 and 70 %, respectively, and the calcium alginate FDAE beads by 55, 55, 52 and 64 %, respectively. The results obtained for TFC was thus similar to that obtained for the TPC data. Based on the TFC data all three encapsulated extracts had very short shelf-lives ranging, from 1.56 weeks (0.39 months) to 6.76 weeks (1.69 months). Under the same conditions and storage periods (i.e. 1 month & 1 week) as that used to determine TPC and TFC, the antioxidant activity of the extracts changed little, i.e. decreased by 0.2, 0.1, 0.8 and 2 %, respectively for FDAE, by 0.7 %, 1 %, 0.1 % and 5.3 %, respectively for the Aq EtOH and by 2, 2, 1.4 and 0.8 %, respectively for the calcium alginate FDAE beads. Moreover, based on antioxidant activity, all three encapsulated extracts had relatively long shelf-lives ranging from 15.6 weeks (3.9 months) to 22.4 weeks (5.6 months). Finally, the determination of the stability of the encapsulated L. leonurus extracts stored under stress conditions (i.e. 40 °C / 75 % RH) and based on marker compound levels was unresolved. Between the time of extract preparation and characterisation until start of the stability study the marrubiin levels in the FDAE, Aq. ETOH and calcium beads had decreased from 22.5, 17.5, and 0.4 ug/mg plant extract, respectively, to 0.30, 0.11, 0.30 μg/mg, respectively, and the leonurine levels from 2.0, 1.4 and 0.7 to 0.46, 0.38 and 0.09 μg/mg, respectively and was too low to conduct a meaningful stability study with the developed validated assay. Overall, all three the encapsulated L. leonurus solid extracts studied were clearly very unstable and did not have suitable long-term storage stability. The modification of the freeze-dried aqueous extract of L. leonurus into a calcium alginate bead form seemed to combat physical instability but did not improve the chemical instability of the aqueous extract. It is therefore recommended that the addition of excipients or other post extract modification (e.g. production of phytosomes) be explored to combat the hygroscopicity of L. leonurus FDAE and ultimately improve its overall product stability.

This work tests the validity of using a commercial cloud condensation nuclei (CCN) counter (CCNc) on the Facility for Airborne Atmospheric Measurements (FAAM) research aircraft. The CCNc was suitable for aircraft work with sta- ble and repeatable supersaturation, temperature and pressure relationships. The sample architecture of the aircraft fitted CCNc was found to transmit particles with acceptable losses in the diameter range of interest as was a pressure control device designed for airborne work. Rosemount inlets, used to sample aerosol, were found to be sensitive to particle density resulting in disparate aerosol being sam- pled with different efficiencies. In dust dominated aerosol inlet efficiency peaks at 10.24 at an optical diameter of 2.91 μm, with a minimum inlet efficiency between 1.78 and 1.51 at 0.28μm. In less dense aerosol inlets sample representatively below 0.6 μm and comparably below 1.0 μm. The thorough testing of the CCNc, associated sampling architecture and mea- surement strategies, enabled vertical and horizontal CCN to be investigated along with other aerosol and cloud microphysical properties in the Southern Equato- rial Pacific (SEP). The primary source of particulates was the South American continent, with sulphate dominating composition. There were strong gradients in aerosol and gas phase chemistry concentration with distance from the coast and in the cloud microphysics measurements where highest droplet numbers and smallest diameters were close to the coast. These data represent an important validatory and parameterisation data set for models of all scales. CCN data were used to calculate the aerosol hygroscopicity parameter, the mean project value, κ, was 0.21 ± 0.18 . There was no evident variation in hygroscopicity with distance from the Chilean coastline suggesting a single dominant source and a well mixed boundary layer up to 907km to the west. CCN measurements were also com- pared to predictions from multiple models of different composition and mixing state assumptions. The best CCN closure used an external mixture of inorganic and organic aerosol components, with a modelled to observed ratio of 1.37 ± 0.32. It was hypothesised that this large ratio and the relatively low bulk hy- groscopicity was influenced by an external mixture. Incorporating this external mixture is imperative if CCN are to be accurately modelled and any subsequent cloud processes accurately captured.

Aerosol particle properties and their impact on air quality, clouds, and the hydrologic cycle remain a critically important factor for the understanding of our atmosphere. Particle hygroscopic growth leads to impacts on direct and indirect radiative forcing properties, the likelihood for particles to act as cloud condensation nuclei, and aerosol-cloud interactions. Current instruments measuring hygroscopic growth have a number of limitations, lacking either the ability to measure size-resolved particles or process samples at a fast enough resolution to be suitable for airborne deployment. Advanced in-situ airborne particle retrieval and measurements of aerosol hygroscopic growth and scattering properties are analyzed and discussed.To improve the analysis of cloud nuclei particles, an updated counterflow virtual impact inlet was characterized and deployed during the 2011 E-PEACE field campaign. Theoretical and laboratory based cut size diameters were determined and validated against data collected from an airborne platform. In pursuit of higher quality aerosol particle hygroscopicity measurements, a newer instrument, the differential aerosol sizing and hygroscopicity probe (DASH-SP) has been developed in the recent past and only flown on a handful of campaigns. It has been proven to provide quality, rapid, size-resolved hygroscopic growth factor data, but was further improved into a smaller form factor making it easier for deployment on airborne platforms. It was flown during the 2013 SEAC4RS field campaign and the data was analyzed to composite air mass based hygroscopicity and refractive index (real portion only) statistics. Additionally, a comparison of bulk and size-resolved hygroscopic growth measurements was conducted. Significant findings include a potential particle size bias on bulk scattering measurements as well as a narrow range of ambient real portion of refractive index values. An investigation into the first reported ambient hygroscopicity measurements of particle shrinkage, or "sub-1" growth is conducted. Possible explanations, including particle restructuring, measurement sensitivity to refractive index, evaporative loss, and influence of ambient external mixtures on data processing are examined.

As medidas do experimento Green Ocean Amazon (GoAmazon 2014/5 ) foram realiza- das nos arredores de Manaus, na região central da Amazônia, durante dois anos, com o objetivo de entender como o ciclo de vida dos aerossóis e das nuvens em condições naturais é influenciado pelas emissões urbanas. Neste contexto, o presente trabalho procurou estudar a higroscopicidade dos aerossóis em condições poluídas pela pluma de Manaus e discuti-la à luz do que era esperado em condições prístinas. A partir desses resultados experimentais, usamos um modelo adiabático de parcela de nuvem para estudar o impacto da poluição de Manaus na formação de nuvens quentes. Observamos altas concentrações de aerossóis vindos de Manaus, com média de Ncn = 2.425 cm 3 e percentis de 25 % e de 75 % respectivamente dados por 937 cm 3 e 3.259 cm 3 . Para a Amazônia prístina, os valores tipicamente encontrados são da ordem de Ncn 400 cm 3 . A higroscopicidade das partículas da poluição urbana é notavelmente baixa, com média de t = (0, 09 ± 0, 01) para todos os diâmetros investigados. Além disso, são altamente heterogêneas quanto à higroscopicidade. As partículas naturais da Amazônia têm higroscopicidade média da ordem de t 0, 14, não sendo tão heterogêneas quanto as partículas de Manaus. Aperfeiçoamos e utilizamos um modelo adiabático de parcela de nuvem para investigar de forma sistemática o impacto da pluma de Manaus nos primeiros estágios de formação das nuvens quentes. O modelo foi validado através da comparação com quatro casos exemplificados na literatura, vindos de modelos conceitualmente semelhantes, mas de implementações numéricas diferentes. Em nossas simulações, consideramos que o formato da distribuição de tamanho das partículas de aerossol poderia variar com a concentração total de partículas, ao irmos da situação limpa para a poluída. Além disso, consideramos também que a higroscopicidade variava com a concentração total e com o tamanho das partículas de aerossol. Isto foi feito em etapas, permitindo representar as partículas de aerossol com crescente grau de detalhamento. Observamos que o número de gotículas na base da nuvem é determinado principalmente pela concentração de partículas e pela velocidade vertical. Em segundo lugar, vem o formato da distribuição de tamanho, e, depois, a higroscopicidade. Mostramos que simulações que não consideram estes outros fatores irão, necessariamente, superestimar o efeito dos aerossóis nas nuvens quentes. Da condição limpa para a condição poluída pela pluma, observamos o aumento da concentração gotículas e a correspondente diminuição do raio efetivo dessa população de gotículas. Observamos, também, a diminuição da fração de aerossóis ativados. Os resultados sugerem que, na condição poluída, as nuvens acumulam água líquida mais rapidamente em seus primeiros 200 m, em relação à condição limpa. / The measurements of the Green Ocean Amazon 2014/5 experiment were carried out on the outskirts of Manaus, in the central Amazon region, for two years, with the objective of understanding how the natural aerosol and cloud life cycles would be perturbed by urban emissions. In this context, the present work aimed at studying the aerosol hygroscopicity under polluted condition, comparing it with the pristine environment. Based on these results, we used an adiabatic cloud parcel model to study the impact of Manaus pollution on the first stages warm clouds formation. We observed high concentrations of aerosols coming from Manaus, with average Ncn = 2.425 cm 3 and percentiles 25 % and 75 % of 937 cm 3 and 3.259 cm 3 res- pectively. For the pristine Amazon, typical values would be about Ncn 400 cm 3 . The hygroscopicity of urban pollution particles were notable low, with average t = (0, 09±0, 01) for all diameters investigated, and a high level of heterogeneity was found. On the other hand, natural particles in the Amazon have a hygroscopicity of about t 0,14 and are not as much heterogeneous. We improved and used an adiabatic cloud parcel model to systematically investigate the impact of the Manaus pollution plume on the first stages of warm cloud develop- ment. The model was validated by comparison with four exemplary cases found in the literature, from conceptually similar models, but with different numerical imple- mentations. In our simulations, we considered that the shape of the size distribution could vary with increasing number concentration, as we moved from the clean to the polluted conditions. We also allowed the hygroscopicity to vary with the concentration and the diameter of the aerosol particles. These were done in stages, hence allowing an increasing level of complexity in the representation of the aerosol particles. We observed that the number of activated cloud droplets is as function primarily of the concentration and the vertical velocity. In second place comes the dependence with the shape of the size distribution and, after that, with the hygroscopicity. We showed that simulations that do not consider these other factors will, necessarily, over predict the effect of aerosols on shallow warm clouds. As expected, when we simulated clean conditions changing towards a polluted one, we found an increase in the number of activated droplets and corresponding decrease of effective radius of those droplets, and of the activated fraction. Our results suggest that, under polluted conditions, clouds accumulate liquid water more rapidly during the first stages of its development than under clean conditions.

Atmospheric aerosols are known to exert a significant influence on the Earth's climate system; however, the magnitude of this influence is highly uncertain because of the complex interaction between aerosols and water vapor to form clouds. Toward reducing this uncertainty, this dissertation outlines a series of laboratory and in-situ field measurements, instrument technique development, and model simulations designed to characterize the ability of aerosols to act as cloud condensation nuclei (CCN) and form cloud droplets. Specifically, we empirically quantify the mixing state and thermodynamic properties of organic aerosols (e.g., hygroscopicity and droplet condensational uptake coefficient) measured in polluted and non-polluted environments including Alaska, California, and Georgia. It is shown that organic aerosols comprise a substantial portion of the aerosol mass and are often water soluble. CCN measurements are compared to predictions from theory in order to determine the error associated with simplified composition and mixing state assumptions employed by current large-scale models, and these errors are used to constrain the uncertainty of global and regional cloud droplet number and albedo using a recently-developed cloud droplet parameterization adjoint coupled with the GMI chemical transport model. These sensitivities are important because they describe the main determinants of climate forcing. We also present two novel techniques for fast measurements of CCN concentrations with high size, supersaturation, and temporal resolution that substantially improve the state of the art by several orders of magnitude. Ultimately, this work represents a step toward better understanding how atmospheric aerosols influence cloud properties and Earth's climate.

<p>This dissertation presents the first findings of aerosol indirect effect in the foothills of the Himalayas (Central Nepal), through a systematic research approach involving satellite data analysis, field campaign, growth factor estimation and numerical modeling studies. Satellite retrieved aerosol optical depth data over the region were first used to identify the dominant modes of spatial/temporal variability of aerosols in the region. Based on the observed dominant spatial mode of aerosol in the pre-monsoon season (Shrestha and Barros 2010, ACP), a field campaign was organized under the Joint Aerosol Monsoon Experiment (JAMEX09) at Dhulikhel and Besisahar to simultaneously measure dry and ambient aerosols size spectra using SMPS and chemical composition using filters (Shrestha et al. 2010, ACP). The diurnal cycle of aerosol number concentration exhibited a consistent peak in the morning and evening period, which was found to be associated with increase in local emission and the delay in ventilation of aerosol through upslope flows and mixing (inferred from an idealized numerical study over Besisahar). The aerosol size distribution was mostly unimodal at night and bimodal during the day, with a consistent larger mode around 100nm and a smaller mode located around 20nm. The chemical composition of PM2.5 was dominated by organic matter at both sites. Organic carbon (OC) comprised the major fraction (64~68%) of the aerosol concentration followed by ionic species (24~26%, mainly and ). Elemental Carbon (EC) compromised 7~10% of the total composition and 27% of OC was found to be water soluble at both sites. The aerosol number concentration increased and decreased in the presence of synoptic scale aerosol plumes and after rainfall events respectively.</p><p>A simple model based on Köhler theory was used to explain the observed growth factor using an assumption of (NH4)2SO4 aqueous solution including the presence of slightly soluble organic compounds (SSC) with an insoluble core as a function of molality and mass-fraction. The measured growth factors suggest that the aerosols are in metastable state due to the strong diurnal cycle of relative humidity (RH). The bulk hygroscopic parameter estimated from the DGF and chemical composition of aerosols suggests less hygroscopic aerosols at both locations as compared to previous studies. The dry aerosol size distribution and the bulk hygroscopic parameters were used to estimate the cloud condensation nuclei (CCN) spectrum, which was vertically scaled up to lifting condensation level (LCL) assuming that the shape and chemical properties of aerosol remains unchanged (Shrestha et al. 2011, submitted to JGR). Finally, these regional CCN spectra for polluted and clean conditions as well as standard continental and marine spectra used in numerical weather prediction models (Cohard et al. 1998) were used to probe CCN sensitivity for a pre-monsoon storm system in Central Nepal during JAMEX09. A significant shift in the maxima of the accumulated precipitation was observed between the continental aerosol spectra (Cohard et al. 1998) and the polluted spectra for Dhulikhel. This shift caused the displacement of rainfall maximum away from the Kulekhani water reserve catchment, which is key to hydropower in Nepal. Detailed analysis of the simulations suggests that simgnificant differences in the space-time variability and intensity of precipitation, if not areally integrated amounts, can be explained by differences in the timing and intensity of latent heat release and absorption due to freezing/melting of hydrometers and evaporative cooling of droplets, strengthening cold pool formation and associated circulations. This numerical study provides the first look on the aerosol indirect effect over Nepal for a single pre-monsoon rainfall event, and how aerosols can potentially affect the precipitation distribution (to be submitted to JGR). In addition, it shows the importance of using regionally consistent CCN spectra in model parameterizations of aerosol-cloud interactions. At local places, the differences in simulated precipitation between marine, JAMEX09 clean and polluted air spectra were smaller (up tp ± 50%) than the difference between those simulations and the standard continental aerosol spectra (±200%).</p> / Dissertation

The feedbacks among aerosols, clouds, and radiation are important components for understanding Earth's climate system and quantifying human-induced climate change, yet the magnitude of these feedbacks remain highly uncertain. Since every cloud droplet in the atmosphere begins with water condensing on a pre-existing aerosol particle, characterizing the ability of aerosols to uptake water vapor and form cloud condensation nuclei (CCN) are key to understanding the microphysics behind cloud formation, as well as assess the impact aerosols have on the Earth system. Through a combination of controlled laboratory experiments and field measurements, this thesis characterizes the ability of atmospheric aerosols to uptake water vapor and become CCN at controlled levels of water vapor supersaturation. The origin of the particle water uptake, termed hygroscopicity, is also explored, being from either the presence of deliquescent soluble material and/or adsorption onto insoluble surfaces. The data collected and presented is comprehensive and includes (1) ground samples of volcanic ash, collected from six recent eruptions re-suspended in the laboratory for analysis, (2) laboratory chamber and flow-tube studies on the oxidation and uptake of surface active organic compounds, and (3) in-situ aircraft measurements of aerosols from the Arctic background, Canadian boreal forests, fresh and aged biomass burning, anthropogenic industrial pollution, and from within tropical cyclones in the Atlantic basin. Having a more thorough understanding of aerosol water uptake will enable more accurate representation of cloud droplet number concentrations in global models, which can have important implications on reducing the uncertainty of aerosol-cloud-climate interactions, as well as additional uncertainties in aerosol transport, atmospheric lifetime, and impact on storm dynamics.

As medidas do experimento Green Ocean Amazon (GoAmazon 2014/5 ) foram realiza- das nos arredores de Manaus, na região central da Amazônia, durante dois anos, com o objetivo de entender como o ciclo de vida dos aerossóis e das nuvens em condições naturais é influenciado pelas emissões urbanas. Neste contexto, o presente trabalho procurou estudar a higroscopicidade dos aerossóis em condições poluídas pela pluma de Manaus e discuti-la à luz do que era esperado em condições prístinas. A partir desses resultados experimentais, usamos um modelo adiabático de parcela de nuvem para estudar o impacto da poluição de Manaus na formação de nuvens quentes. Observamos altas concentrações de aerossóis vindos de Manaus, com média de Ncn = 2.425 cm 3 e percentis de 25 % e de 75 % respectivamente dados por 937 cm 3 e 3.259 cm 3 . Para a Amazônia prístina, os valores tipicamente encontrados são da ordem de Ncn 400 cm 3 . A higroscopicidade das partículas da poluição urbana é notavelmente baixa, com média de t = (0, 09 ± 0, 01) para todos os diâmetros investigados. Além disso, são altamente heterogêneas quanto à higroscopicidade. As partículas naturais da Amazônia têm higroscopicidade média da ordem de t 0, 14, não sendo tão heterogêneas quanto as partículas de Manaus. Aperfeiçoamos e utilizamos um modelo adiabático de parcela de nuvem para investigar de forma sistemática o impacto da pluma de Manaus nos primeiros estágios de formação das nuvens quentes. O modelo foi validado através da comparação com quatro casos exemplificados na literatura, vindos de modelos conceitualmente semelhantes, mas de implementações numéricas diferentes. Em nossas simulações, consideramos que o formato da distribuição de tamanho das partículas de aerossol poderia variar com a concentração total de partículas, ao irmos da situação limpa para a poluída. Além disso, consideramos também que a higroscopicidade variava com a concentração total e com o tamanho das partículas de aerossol. Isto foi feito em etapas, permitindo representar as partículas de aerossol com crescente grau de detalhamento. Observamos que o número de gotículas na base da nuvem é determinado principalmente pela concentração de partículas e pela velocidade vertical. Em segundo lugar, vem o formato da distribuição de tamanho, e, depois, a higroscopicidade. Mostramos que simulações que não consideram estes outros fatores irão, necessariamente, superestimar o efeito dos aerossóis nas nuvens quentes. Da condição limpa para a condição poluída pela pluma, observamos o aumento da concentração gotículas e a correspondente diminuição do raio efetivo dessa população de gotículas. Observamos, também, a diminuição da fração de aerossóis ativados. Os resultados sugerem que, na condição poluída, as nuvens acumulam água líquida mais rapidamente em seus primeiros 200 m, em relação à condição limpa. / The measurements of the Green Ocean Amazon 2014/5 experiment were carried out on the outskirts of Manaus, in the central Amazon region, for two years, with the objective of understanding how the natural aerosol and cloud life cycles would be perturbed by urban emissions. In this context, the present work aimed at studying the aerosol hygroscopicity under polluted condition, comparing it with the pristine environment. Based on these results, we used an adiabatic cloud parcel model to study the impact of Manaus pollution on the first stages warm clouds formation. We observed high concentrations of aerosols coming from Manaus, with average Ncn = 2.425 cm 3 and percentiles 25 % and 75 % of 937 cm 3 and 3.259 cm 3 res- pectively. For the pristine Amazon, typical values would be about Ncn 400 cm 3 . The hygroscopicity of urban pollution particles were notable low, with average t = (0, 09±0, 01) for all diameters investigated, and a high level of heterogeneity was found. On the other hand, natural particles in the Amazon have a hygroscopicity of about t 0,14 and are not as much heterogeneous. We improved and used an adiabatic cloud parcel model to systematically investigate the impact of the Manaus pollution plume on the first stages of warm cloud develop- ment. The model was validated by comparison with four exemplary cases found in the literature, from conceptually similar models, but with different numerical imple- mentations. In our simulations, we considered that the shape of the size distribution could vary with increasing number concentration, as we moved from the clean to the polluted conditions. We also allowed the hygroscopicity to vary with the concentration and the diameter of the aerosol particles. These were done in stages, hence allowing an increasing level of complexity in the representation of the aerosol particles. We observed that the number of activated cloud droplets is as function primarily of the concentration and the vertical velocity. In second place comes the dependence with the shape of the size distribution and, after that, with the hygroscopicity. We showed that simulations that do not consider these other factors will, necessarily, over predict the effect of aerosols on shallow warm clouds. As expected, when we simulated clean conditions changing towards a polluted one, we found an increase in the number of activated droplets and corresponding decrease of effective radius of those droplets, and of the activated fraction. Our results suggest that, under polluted conditions, clouds accumulate liquid water more rapidly during the first stages of its development than under clean conditions.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / The acerola tropical fruit and papaya are of great industrial interest for its nutritional and sensory characteristics. Due to the perishable nature of these fruits to adopt conservation methods is necessary. The present study aimed at obtaining "blends" powder from freeze-drying the pulp of acerola and papaya. First were performed compounds central rotational schedules, which evaluated the influence of lyophilization time and maltodextrin concentration and humidity on the hygroscopicity of the powders. From the results of the design were produced powders from acerola and papaya in optimal process conditions based on lower hygroscopicity, moisture was not considered by the planning because the powders obtained were within the standards established by Brazilian legislation. From the physico-chemical characterizations of the pulps and the pulps fresh powder was noticed good nutritional quality for both pulps primarily by ascorbic acid, in addition to considerable amounts of anthocyanins and carotenoids in relation to adsorption isotherms both the powders exhibited type III curves concave-shaped "J" typically associated with the food powders from fruit, yet papaya pulp powder showed reversal of the effect of temperature on adsorption capacity for water a range of water activity of 0,8. The Oswin model was the best fit curves for the prediction of the pulp powder at all temperatures analyzed for papaya pulp, the model proposed by BET was the best fit the data. Then experiment was conducted mixtures simplex centroid increased to three components (acerola pulp, papaya pulp and maltodextrin) to obtain the "blend" lyophilized powder, by determining the effect of the proportions of the mixture on the hygroscopicity , solubility, time and degree of rehydration Caking. The time lyophilization of "blends" was the simple arithmetic average between the times of lyophilization obtained by central composite design for the pulp powder acerola and papaya. The results of qualitative analysis of the mixture enabled the choice of test 6 with the proportions 25% acerola pulp, 50% papaya pulp and 25% maltodextrin as best assay for production of "blend" powder. The "blend" powder obtained under optimum conditions showed good physicochemical characteristics, in relation to sorption isotherms, the GAB model was the best fit the experimental data, where the curves were type III. Then there was the study of the stability of the "blend" powder in storage period of 20 days packed in polyethylene wrapped in aluminum foil. Thus, it was concluded that, after this storage period, the "blend" powder, the patient was still in powder form and has good chemical-physical characteristics and hygroscopic. / A acerola e mamÃo sÃo frutos tropicais de grande interesse industrial por suas caracterÃsticas nutricionais e sensoriais. Em virtude do carÃter perecÃvel desses frutos a adoÃÃo de mÃtodos de conservaÃÃo faz-se necessÃria. O presente trabalho teve como objetivo obter âblendsâ em pà a partir da liofilizaÃÃo das polpas de acerola e mamÃo. Primeiramente foram realizados planejamentos compostos central rotacionais, onde se avaliou a influÃncia do tempo de liofilizaÃÃo e concentraÃÃo de maltodextrina sobre a higroscopicidade e umidade dos pÃs obtidos. A partir dos resultados do planejamento foram produzidos os pÃs de acerola e mamÃo em condiÃÃes Ãtimas, baseadas na menor higroscopicidade. A umidade nÃo foi considerada pelo planejamento, pois os pÃs encontravam-se dentro do especificado pela legislaÃÃo brasileira. A partir das caracterizaÃÃes fÃsico-quÃmicas das polpas in natura e das polpas em pà percebeu-se boa qualidade nutricional para ambas as polpas principalmente pelo teor de Ãcido ascÃrbico, alÃm de considerÃveis teores de antocianinas e carotenÃides, em relaÃÃo Ãs isotermas de adsorÃÃo, ambos os pÃs apresentaram curvas do tipo III, cÃncavas em formato de âJâ, tipicamente associado a pÃs a base de frutos, contudo a polpa de mamÃo em pà apresentou inversÃo do efeito da temperatura sobre a capacidade de adsorÃÃo da Ãgua em uma faixa de atividade de Ãgua de 0,75. O modelo de Oswin foi o que melhor se ajustou na prediÃÃo das curvas para polpa de acerola em pà nas temperaturas analisadas. Para a polpa de mamÃo, o modelo proposto por BET foi o que melhor se ajustou aos dados. Em seguida realizou-se delineamento experimental de misturas simplex centrÃide aumentado para 3 componentes (polpa de acerola; polpa de mamÃo e maltodextrina) para obter-se âblendâ em pà liofilizado, atravÃs da determinaÃÃo do efeito das proporÃÃes da mistura sobre a higroscopicidade, solubilidade, tempo de reidrataÃÃo e grau de Caking. O tempo de liofilizaÃÃo dos âblendsâ foi à mÃdia aritmÃtica simples entre os tempos de liofilizaÃÃo obtidos pelo planejamento composto central para as polpas em pà de acerola e mamÃo. Os resultados da anÃlise qualitativa da mistura possibilitou a escolha do ensaio 6 com as proporÃÃes 25% de polpa de acerola, 50% de polpa de mamÃo e 25% de maltodextrina como melhor ensaio para produÃÃo do âblendâ em pÃ. O âblendâ em pà nas condiÃÃes Ãtimas apresentou boas caracterÃsticas fÃsico-quÃmicas, em relaÃÃo Ãs isotermas de sorÃÃo, o modelo de GAB foi o que melhor se ajustou aos dados experimentais, onde as curvas foram do tipo III. Em seguida, realizou-se o estudo da estabilidade do âblendâ em pÃ, pelo perÃodo de 20 dias acondicionados em embalagem de polietileno envolvidos em folha de alumÃnio. Com isso, concluiu-se que, apÃs este perÃodo de armazenamento, o âblendâ em pÃ, ainda apresentava-se na forma de pà e com boas caracterÃsticas fÃsico-quÃmicas e higroscÃpicas.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / The objective of this research was to obtain powder from the pulp of integral acerola two drying methods (spray-dryer and freeze drying), and the determination of physical and chemical stability and hygroscopic and morphological characteristics. Acerola pulps were acquired in the trade of Fortaleza. The pulp was characterized and post as the physicochemical, colorimetric and morphological parameters. The study of the stability of the powders was carried out in three distinct packaging for a period of 90 days. The adsorption isotherms were also determined. The results indicated optimal conditions for drying spray-dryer using drying temperature of 154 ÂC and the pulp concentration maltodextrin 17,1%, while in the lyophilizer, 19,1% maltodextrin with lyophilization time of 24 hours. All physico-chemical parameters evaluated in the whole pulp undergo change after drying. The drying spray-dryer powder generated with lower humidity, and lyophilization produced a more hygroscopic powder, with a greater degree of caking, and better color preservation, the pH being a parameter of small variation. The study of the stability of acerola pulp powder obtained by different drying methods allowed us to observe increased humidity and coordinate a* b* and decreased ascorbic acid and brightness. The use of laminated packaging laminate vacuum was effective to maintain moisture and hygroscopic powder, with less loss of ascorbic acid for packaging laminda vacuum. The BET model best fit the adsorption isotherms of the lyophilized powder acerola pulp, while for the spray-dryer model Oswin better adjusted to 25 ÂC, and Henderson model for 35 and 45 ÂC. Morphological characterization showed by analysis of Microcopia Scanning Electron (SEM), X-ray diffraction (XRD) spectroscopy and Fourier Transform Infrared (FTIR-ATR) that the lyophilization process generates an amorphous powder and adding maltodextrin protects the frame of samples and permits lower moisture absorption also show similar composition between samples, and a higher absorbance obtained is lyophilized in the whole sample. / O objetivo desta pesquisa foi a obtenÃÃo de pà a partir da polpa de acerola integral por dois mÃtodos de secagem (spray-dryer e liofilizaÃÃo), assim como a determinaÃÃo da estabilidade fÃsico-quÃmica e caracterÃsticas higroscÃpicas e morfolÃgicas. As polpas de acerola foram adquiridas no comÃrcio de Fortaleza-CE. Caracterizou-se a polpa e os pÃs quanto a parÃmetros fÃsico-quÃmicos e colorimÃtricos e morfolÃgicos. O estudo da estabilidade dos pÃs foi realizado em trÃs embalagens distintas por um perÃodo de 90 dias. Determinou-se ainda as isotermas de adsorÃÃo. Os resultados indicaram condiÃÃes Ãtimas de secagem em spray-dryer utilizando temperatura de secagem de 154ÂC e concentraÃÃo de maltodextrina na polpa de 17,1%, enquanto para o liofilizador, 19,1% de maltodextrina com tempo de liofilizaÃÃo de 24 horas. Todos os parÃmetros fÃsico-quÃmicos avaliados na polpa integral sofrem variaÃÃo apÃs secagem. A secagem em spray-dryer gerou pà com menor umidade, e a liofilizaÃÃo gerou um pà mais higroscÃpico, com maior grau de caking, e melhor preservaÃÃo da cor, sendo o pH um parÃmetro de pequena variaÃÃo. O estudo da estabilidade das polpas de acerola em pà obtidas por diferentes mÃtodos de secagem permitiu observar aumento da umidade e das coordenadas a* e b* e diminuiÃÃo do Ãcido ascÃrbico e luminosidade. O uso de embalagens laminada e laminada a vÃcuo mostrou-se eficaz para a manutenÃÃo da umidade e higroscopicidade dos pÃs, com menor perda de Ãcido ascÃrbico para a embalagem laminada a vÃcuo. O modelo de BET melhor se ajustou as isotermas de adsorÃÃo o pà de polpa de acerola liofilizado, enquanto para o spray-dryer o modelo de Oswin melhor se ajustou a 25ÂC, e o modelo de Henderson para 35 e 45ÂC. A caracterizaÃÃo morfolÃgica mostrou pelas anÃlises de Microcopia EletrÃnica de Varredura (MEV), DifraÃÃo de Raios-X (DRX) e Espectroscopia de Infravermelho com Transformada de Fourier (FTIR-ATR) que o processo de liofilizaÃÃo gera um pà amorfo e que a adiÃÃo de maltodextrina protege a estruturadas amostras e permite uma menor absorÃÃo de umidade, ainda mostra composiÃÃo similar entre as amostras, e que uma maior absorbÃncia à obtida em amostra integral liofilizada.