CIRCULATION AND SUSPENDED PARTICULATE MATTER TRANSPORT IN A TIDALLY DOMINATED ESTUARY: CARAVELAS ESTUARY, BAHIA, BRAZIL

The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms(-1)) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms(-1)) and the peak flood currents were 0.75 and 0.60 ms(-1), respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m(3)s(-1) at the ebb and flood, respectively, with a residual -630 m(3)s(-1). The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg. L(-1) at the estuary mouth, to 10 mg.L(-1) at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.

HYDRODYNAMICS AND SUSPENDED SEDIMENT TRANSPORT IN THE CAMBORIU ESTUARY - BRAZIL: PRE JETTY CONDITIONS

Estuarine hydrodynamics is a key factor in the definition of the filtering capacity of an estuary and results from the interaction of the processes that control the inlet morphodynamics and those that are acting in the mixing of the water in the estuary. The hydrodynamics and suspended sediment transport in the Cambori estuary were assessed by two field campaigns conducted in 1998 that covered both neap and spring tide conditions. The period measured represents the estuarine hydrodynamics and sediment transport prior to the construction of the jetty in 2003 and provides important background information for the Cambori estuary. Each field campaign covered two complete tidal cycles with hourly measurements of currents, salinity, suspended sediment concentration and water level. Results show that the Cambori estuary is partially mixed with the vertical structure varying as a function of the tidal range and tidal phase. The dynamic estuarine structure can be balanced between the stabilizing effects generated by the vertical density gradient, which produces buoyancy and stratification flows, and the turbulent effects generated by the vertical velocity gradient that generates vertical mixing. The main sediment source for the water column are the bottom sediments, periodically resuspended by the tidal currents. The advective salt and suspended sediment transport was different between neap and spring tides, being more complex at spring tide. The river discharge term was important under both tidal conditions. The tidal correlation term was also important, being dominant in the suspended sediment transport during the spring tide. The gravitational circulation and Stokes drift played a secondary role in the estuarine transport processes.

Experimento para quantificar a eficiência de aspersão de líquidos: aplicação em distribuidores espinha de peixe

This paper describes a device developed on the pilot scale and a simple approach to compare liquid distributor efficiencies. The technique consists basically of analyzing the mass of the liquid collected in 21 vertical pipes measuring 52 mm in internal diameter and 800 mm in length placed in a quadratic arrangement and positioned below the distributor A 50 mm thick acrylic blanket that does not disperse liquids was placed between the distributor and the pipe bank to avoid splashes. Assays were carried out with ladder-type distributors equipped with 4 parallel pipes each for a column measuring 400 nun in diameter as an example of the application. The number (n) of orifices (95, 127, and 159 orifices/m(2)), orifice diameter (d) (2, 3, and 4 mm) and the flowrate (q) (1.2; 1.4; and 1.6 m(3)/h) were varied. The best spread efficiency, which presented the lowest standard deviation, was achieved with 159 orifices, 2 mm and 1.4 m(3)/h. The pressure (p) at the distributor inlet for this condition was only 51000 Pa (0.51 kgf/cm(2)), while the average velocity (v) was 6.3 m/s in each orifice. These results show some limitations of the practical rules used in distributor designs.

Ecological distribution of the shrimp Litopenaeus schmitti (Burkenroad, 1936) (Decapoda, Penaeoidea) in Ubatuba Bay, Sao Paulo, Brazil

The penaeidean Litopenaeus schmitti, popularly known as white shrimp, is a species of great economic importance, being a target of fishing fleets in the southeast region of Brazil. It is distributed through the western Atlantic, from Cuba to Brazil, until Rio Grande do Sul. Adults are found from shallow depths up to 30 m and have been found to depths of 47 m in the state of Rio de Janeiro, while juveniles are located in bays and estuaries. The studied species is seasonally distributed in the region of Ubatuba. The objectives of this study are to analyze the abundance and ecological distribution of L. schmitti and to assess if and when juveniles use the Indaia estuary during their life cycle. Furthermore, the hypothesis was tested that the main period of recruitment in the bay coincides with the period of closure of fisheries defined by the Instruction of IBAMA. To that end, samples were taken monthly from July 2005 through June 2007, both in Ubatuba Bay and in the estuary formed by the Rio Indaia. At each sampling station, salinity, temperature (bottom), depth, organic matter content (%), and grain size of sediments were measured. We found that the largest catches in the estuary were in late spring and early summer. In Ubatuba Bay, peak catches occurred during winter and early spring, whereas in the second year, already in May, there was a high peak capture. The variation in the number of individuals was correlated with some environmental factors both in the estuary and in the inlet (p < 0.05). In the estuary, abundance was positively correlated with temperature (p = 0.008) and organic matter (p = 0.025) and negatively with depth (p = 0.009). Regarding the Ubatuba Bay, only temperature (p = 0.034) and depth (p = 0.013) were significantly associated with the distribution of the shrimp, both being negative relations. The shrimp L. schmitti uses both the estuarine as well the shore environment, particularly the Ubatuba estuary and its adjacent bay, to complete its life cycle. The proposed period of fisheries closure (between March to May in the state of Sao Paulo) for this and other shrimps coincides with individuals capable of reproduction entering the inlet and thus are being protected.

Unmanned platform for long-range remote analysis of volatile compounds in air samples

This paper describes a long-range remotely controlled CE system built on an all-terrain vehicle. A four-stroke engine and a set of 12-V batteries were used to provide power to a series of subsystems that include drivers, communication, computers, and a capillary electrophoresis module. This dedicated instrument allows air sampling using a polypropylene porous tube, coupled to a flow system that transports the sample to the inlet of a fused-silica capillary. A hybrid approach was used for the construction of the analytical subsystem combining a conventional fused-silica capillary (used for separation) and a laser machined microfluidic block, made of PMMA. A solid-state cooling approach was also integrated in the CE module to enable controlling the temperature and therefore increasing the useful range of the robot. Although ultimately intended for detection of chemical warfare agents, the proposed system was used to analyze a series of volatile organic acids. As such, the system allowed the separation and detection of formic, acetic, and propionic acids with signal-to-noise ratios of 414, 150, and 115, respectively, after sampling by only 30 s and performing an electrokinetic injection during 2.0 s at 1.0 kV.

Processing of Apeiba tibourbou Aubl. Extract Via Spray Drying

The effects of drying air inlet temperature (IT) and concentration of Aerosil 200 (C-A) on several properties of spray-dried Apeiba tibourbou extracts were investigated following a 3(2) full factorial design. Powder recovery varied from 9.83 to 46.95% and dried products showed moisture contents below 7%. Although the spray-dried products lost some of their polyphenols, they still present excellent antioxidant activity, opening perspectives for its use to medicinal purpose. C-A exerted a key role on the properties of spray-dried extracts, while IT did not present a significative influence. Aerosil (R) 200 proved to be an interesting alternative as an excipient for the drying of the herbal extract, even at intermediate concentrations such as 15%. The best combination of conditions to use for obtaining dry A. tibourbou extracts with adequate physicochemical and functional properties involves an IT of 100 degrees C and a C-A of 15%.

Development of Nanoinjector Devices for Electrospray Ionization - Tandem Mass Spectrometry (ESI-MSn)

In mass spectrometric (MS) systems with electrospray ionization (ESI), the sample can be analyzed coupled to separation systems (such as liquid chromatography or capillary electrophoresis) or simply by direct infusion. The greatest benefit of the type of injection is the possibility of continuous use of small amounts of samples over a long period of time. This extended analysis time allows a complete study of fragmentation by mass spectrometry, which is critical for structure elucidation of new compounds, or when using an ion trap mass analyzer. The injector filled with the sample is placed at the ESI source inlet creating an electric field suitable for the continuous formation of a spray (solvent and sample) and consequently, the gradual and even release of the sample. For the formation of the spray, is necessary that the injector end is metalized. The formation of a bilayer of titanium and gold provided an excellent attachment of the film, resulting in a nanoinjector for ionization/spray formation in the system for MS. The nanoinjectors showed high repeatability and stability over 100 min by continuous sampling with 10 mu L of sample.

In vivo hydroquinone exposure causes tracheal hyperresponsiveness due to TNF secretion by epithelial cells

Hydroquinone (HQ) is the main oxidative substance in cigarette smoke and a toxic product of benzene biotransformation. Although the respiratory tract is an inlet pathway of HQ exposure, its effect on airway muscle responsiveness has not been assessed. We thus investigated the effects of low dose in vivo HQ-exposure on tracheal responsiveness to a muscarinic receptor agonist. Male Swiss mice were exposed to aerosolised 5% ethanol/saline solution (HQ vehicle; control) or 0.04 ppm HQ (1 h/day for 5 days) and tracheal rings were collected 1 h after the last exposure. HQ exposure caused tracheal hyper-responsiveness to methacholine (MCh), which was abolished by mechanical removal of the epithelium. This hyperresponsiveness was not dependent on neutrophil infiltration, but on tumour necrosis factor (TNF) secretion by epithelial cells. This conclusion was based on the following data: (1) trachea from HQ-exposed mice presented a higher amount of TNF, which was abrogated following removal of the epithelium; (2) the trachea hyperresponsiveness and TNF levels were attenuated by in vivo chlorpromazine (CPZ) treatment, an inhibitor of TNF synthesis. The involvement of HQ-induced TNF secretion in trachea mast cell degranulation was also demonstrated by the partial reversion of tracheal hyperresponsiveness in sodium cromoglicate-treated animals, and the in vivo HQ-exposure-induced degranulation of trachea connective tissue and mucosal mast cells, which was reversed by CPZ treatment. Our data show that in vivo HQ exposure indirectly exacerbates the parasympathetic-induced contraction of airway smooth muscle cells, mediated by TNF secreted by tracheal epithelial cells, clearly showing the link between environmental HQ exposure and the reactivity of airways. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Microencapsulation of Ketoprofen in Blends of Acrylic Resins by Spray Drying

Microparticles of ketoprofen entrapped in blends of acrylic resins (Eudragit RL 30D and RS 30D) were successfully produced by spray drying. The effects of the proportion ketoprofen : polymer (1: 1 and 1: 3) and of spray-drying parameters (drying gas inlet temperatures of 80 and 100 degrees C; microencapsulating composition feed flow rates of 4 and 6 g/min) on the microparticles properties (drug content, encapsulation efficiency, mean particle size, moisture content, and dissolution behavior) were evaluated. Differential scanning calorimetry (DSC) thermograms and X-ray diffractograms of the spray-dried product, the free drug, and the physical mixture between the free drug and spray-dried composition (blank) were carried out. Microparticles obtained at inlet temperature of 80 degrees C, feed flow rate of 4 g/min, and ketoprofen : acrylic resin ratio of 1: 3 presented an encapsulation efficiency of 88.1%, moisture content of 5.8%, production yield around 50%, and a higher reduction in dissolution rate of the entrapped ketoprofen. Sigmoidal shape dissolution profiles were presented by the spray-dried microparticles. The dissolution profiles were relatively well described by the Weibull model, a showing high coefficient of determination, R-2, and a mean absolute error between experimental and estimated values of between 4.6 and 10.1%.

Experimental investigation of gravitational gas separation in an inclined annular channel

The oil industry uses gas separators in production wells as the free gas present in the suction of the pump reduces the pumping efficiency and pump lifetime. Therefore, free gas is one of the most important variables in the design of pumping systems. However, in the literature there is little information on these separators. It is the case of the inverted-shroud gravitational gas separator. It has an annular geometry due to the installation of a cylindrical container in between the well casing and pioduction pipe (tubing). The purpose of the present study is to understand the phenomenology and behavior of inverted-shroud separator. Experimental tests were performed in a 10.5-m-length inclinable glass tube with air and water as working fluids. The water flow rate was in the range of 8.265-26.117 l/min and the average inlet air mass flow rate was 1.1041 kg/h, with inclination angles of 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, 80 degrees and 85 degrees. One of the findings is that the length between the inner annular level and production pipe inlet is one of the most important design parameters and based on that a new criterion for total gas separation is proposed. We also found that the phenomenology of the studied separator is not directly dependent on the gas flow rate, but on the average velocity of the free surface flow generated inside the separator. Maps of efficiency of gas separation were plotted and showed that liquid flow rate, inclination angle and pressure difference between casing and production pipe outlet are the main variables related to the gas separation phenomenon. The new data can be used for the development of design tools aiming to the optimized project of the pumping system for oil production in directional wells. (C) 2012 Elsevier Inc. All rights reserved.

Development of nanoinjector devices for electrospray ionization - tandem mass spectrometry (ESI-MSn)

In mass spectrometric (MS) systems with electrospray ionization (ESI), the sample can be analyzed coupled to separation systems (such as liquid chromatography or capillary electrophoresis) or simply by direct infusion. The greatest benefit of the type of injection is the possibility of continuous use of small amounts of samples over a long period of time. This extended analysis time allows a complete study of fragmentation by mass spectrometry, which is critical for structure elucidation of new compounds, or when using an ion trap mass analyzer. The injector filled with the sample is placed at the ESI source inlet creating an electric field suitable for the continuous formation of a spray (solvent and sample) and consequently, the gradual and even release of the sample. For the formation of the spray, is necessary that the injector end is metalized. The formation of a bilayer of titanium and gold provided an excellent attachment of the film, resulting in a nanoinjector for ionization/spray formation in the system for MS. The nanoinjectors showed high repeatability and stability over 100 min by continuous sampling with 10 µL of sample.

Prediction of sediments toxicity using consensus-based sediment quality guidelines and benthic foraminifera in the Ria de Aveiro(Portugal)

Ria de Aveiro is a large and shallow lagoon on the west coast of Portugal (40º38’N, 8º45´W), characterized by a complex geometry. It includes large areas of intertidal flats and a network of narrow channels which are connected to the Atlantic by an artificial inlet. Tides are the main forcing of the hydrology and physical processes of the lagoon. The deeper areas near the inlet are characterized by strong marine influence through tidal inflow, with high values of current velocity (>1m/s) and tidal range (2–3 m at spring tides), while in remote shallow areas, the circulation and the sea water inflow are reduced. These remote areas are more influenced by fresh waters received from several rivers and several small streams. The Aveiro lagoon is a very important ecosystem but as been used as recipient for various kinds of anthropogenic wastes resulting from the high population density, urban activities and industrial development. One of the most important Portuguese industrial centre is located in the lagoon margins. Ria de Aveiro is a coastal lagoon under huge direct antropization. This system also suffers strong diffuse antropization. This work is related with diffuse antropization linked with chemical pollution which may lead to biological stress and collapse.