Search

The performance of orifice plates in real-time monitoring of oil, gas and water standard flow rates was investigated. To this end, a multi-rate test was implemented in two production wells routed individually to a test separator in field operational conditions. The well flow rate was varied in steps by changing the choke opening. The ranges of fluid properties and flow conditions achieved during the experiment were: wellhead pressure from 9073kPa to 13,278kPa, wellhead temperature from 47.8°C to 53.5°C, downstream choke pressure from 6770kPa to 7913kPa, downstream choke temperature from 41.6°C to 49.1°C, gas-oil-ratio from 1144 Sm 3 / Sm 3 to 2068 Sm 3 / Sm 3, water-cut from 4.64% to 58.35%, standard oil specific gravity from 0.7988 to 0.8058, standard gas specific gravity from 0.7340 to 0.7550, standard oil flow rate from 46.86 Sm 3 / d to 266.65 Sm 3 / d, standard gas flow rate from 62.68 × 10 3 Sm 3 / d to 296.65 × 10 3 Sm 3 / d, standard water flow rate from 18.06 m 3 / d to 159.33 m 3 / d . The wells tested showed a different dynamic behavior: while well #2 did not vary significantly the stream composition with flow rate, well #1 produced under gas coning, a near well-reservoir phenomenon that governs the contribution of the reservoir gas-cap to the total stream composition. The multi-rate tests generated two data sets with 1424 flow conditions through two flange-tap orifice plates installed upstream (wellhead) and downstream of a cage choke valve. The ranges of orifice variables were: orifice diameter from 0.03479m to 0.0430m, beta factor from 0.4946 to 0.6507, differential pressure from 15kPa to 187kPa. The virtual metering system presented in Paz et al. (2010) was used to correlate the experimental data. The associated model, suitable for differential pressure measuring devices, includes effects such as flow concentration and slip (through Chisholm's correlation), generalizing the mass flow rate versus pressure drop relationship for multiphase flow. The total mass flow rate depends on a set of variables evaluated at metering conditions: density and viscosity of the liquid and gas phase, mass quality, pressure drop across the flow meter and geometry (contraction area and beta factor). The determination of the fluid properties at metering conditions was made by using black-oil correlations. These correlations are based on a set of input variables at standard condition that characterizes the stream composition such as gas-oil ratio, water-oil ratio and specific gravities of each phase. A comparison was made between the multiphase flow rates predicted by the model and the ones simultaneously measured at the test separators. The oil, gas and water standard volumetric flow rate deviations (coefficients of variation of the root mean square deviations) were below 3.52 % . It was theoretically demonstrated and experimentally verified that a systematic error exists when the homogeneous model (equal phase velocities) is considered in the formulation, resulting in a flow rate underestimation. When the homogeneous model was used to correlate the data, this effect increased the deviation up to 10.5 % . Flow pattern at the wellhead was characterized as intermittent and annular-mist. Lockhart-Martinelli parameter varied from 0.362 to 0.836; despite of the experimental data being beyond the wet gas region, the multi-rate tests showed that Chisholm's over-reading can be successfully extrapolated to these range. [ABSTRACT FROM AUTHOR]

The addition of 10 wt.% Fe to a Cu6Sn5 alloy resulted in a significant improvement in the cycle lifetime of the alloy. The volumetric capacity of the Cu6Sn5–10 wt.% Fe material at 100 cycles is almost three times the theoretical capacity of graphite. [Copyright &y& Elsevier]

Abstract: Objective: The aim of this study was to evaluate the epidemiology of bacterial and fungal pneumonia in lung transplant (LT) recipients and to assess donor-to-host transmission of these microorganisms. Materials and Methods: We retrospectively studied all positive cultures from bronchoalveolar lavage (BAL) of 49 lung transplant recipients and their donors from August 2003 to April 2007. Results: There were 108 episodes of pneumonia during a medium follow-up of 412 days (range, 1–1328 days). The most frequent microorganisms were: Pseudomonas aeruginosa (n = 36; 33.3%), Staphylococcus aureus (n = 29; 26.8%), and Aspergillus spp. (n = 18; 16%). Other fungal infections were due to Fusarium spp., Cryptococcus neoformans, and Paracoccidioides brasiliensis. Of the 31 donors with positive BAL, 15 had S. aureus. There were 21 pretransplant colonized recipients (43%) and 16 of them had suppurative underlying lung disease. P. aeruginosa was the most frequent colonizing organism (59% of pretransplant positive cultures). There were 11 episodes of bacteremia and lungs were the source in 5 cases. Sixteen deaths occurred and 6 (37.5%) were due to infection. Statistical analyses showed association between pretransplant colonizing microorganisms from suppurative lung disease patients and pneumonias after lung transplantation (RR = 4.76; P = .04; 95% CI = 1.02–22.10). No other analyzed factor was significant. Conclusions: Bacterial and fungal infections are frequent and contribute to higher mortality in lung transplant recipients. P. aeruginosa is the most frequent agent of respiratory infections. This study did not observe any impact of donor lung organisms on pneumonia after lung transplantation. Nevertheless, we demonstrated an association between pretransplant colonizing microorganisms and early pneumonias in suppurative lung transplant recipients. [Copyright &y& Elsevier]

Poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) plays a relevant role in the device performance as hole extraction layer (HTL) of inverted perovskite solar cells. Here, we show a simple low-temperature spin coating method for obtaining homogenous graphene-doped thin films of PEDOT:PSS with improved electrical conductivity without decreasing optical transmittance. Moreover, the crystallinity and stability in ambient conditions of the perovskite grown on it are enhanced. The hydrophobic character of graphene probably blocks undesirable reactions hampering degradation. By impedance spectroscopy it is demonstrated better charge extraction and reduction of recombination mechanisms at the doped-HTL/perovskite interface, resulting in improved photovoltaic parameters of the solar cell and greater stability at room operation conditions thus providing a simple and cost-effective method of preparing solar cells based on hybrid perovskites. Unlabelled Image • Addition of graphene platelets into PEDOT:PSS layers improves up to 10 times its conductivity, maintaining the transmittance. • MAPbI 3 film grown on graphene-doped PEDOT:PSS exhibits large crystallite size and lower PbI2 content, leading high stability. • Inverted solar cells based on graphene-doped PEDOT:PSS show better photovoltaic parameters by increasing charge extraction. [ABSTRACT FROM AUTHOR]

Synthesized iron oxide nanoparticles have been proposed as an alternative to non-dispersed iron oxides for in situ environmental remediation. Their colloidal properties enable their injection into porous media, i.e. soils and aquifers, and offer a higher efficiency in removing contaminants. However, this dispersed state is also the cause of concerns over their environmental fate and toxicity, e.g., by increasing the exposure time to aquatic organisms in groundwater remediation activities. Therefore, the objective of in situ groundwater remediation is to establish local reactive barriers in the subsurface by injection by means of reactive colloids with a controllable mobility under in situ conditions and present as colloids as shortly as possible. In this work, we examined the toxicity of humic acid-coated colloidal goethite nanoparticles in Daphnia magna . The adaptation of the ecotoxicological standard tests for nanomaterials is intensely discussed to increase comparability and reliability of results. In the present study, the effect of different exposure conditions on goethite nanoparticles colloidal behaviour and acute Daphnia immobilization effects was investigated. For this purpose, iron concentration in the water column, aggregation state and acute effects were studied in: i) a standard test, ii) test design with exposure dispersions incubated for a week and iii) water accommodated fraction. Despite the different aggregation and settling of the particles found between the approaches tested, no differences in toxicity were observed. Coated nanoparticles were found clogging up the filtering apparatus, and/or adhered to the exoskeleton, hindering the swimming and molting, and causing the immobilization and death of the organisms at doses of ≥ 943 mg/L (EC50). The data suggests that the toxic potential of these nanoparticles is mainly related to the physical interaction with the daphnids. [ABSTRACT FROM AUTHOR]

The primary isolation of a Mycobacterium sp. of the Mycobacterium tuberculosis complex from an infected animal provides a definitive diagnosis of tuberculosis. However, as Mycobacterium bovis and Mycobacterium caprae are difficult to isolate, particularly for animals in the early stages of disease, success is dependent on the optimal performance of all aspects of the bacteriological process, from the initial choice of tissue samples at post-mortem examination or clinical samples, to the type of media and conditions used to cultivate the microorganism. Each step has its own performance characteristics, which can contribute to sensitivity and specificity of the procedure, and may need to be optimized in order to achieve the gold standard diagnosis. Having isolated the slow-growing mycobacteria, species identification and fine resolution strain typing are keys to understanding the epidemiology of the disease and to devise strategies to limit transmission of infection. New technologies have emerged that can now even discriminate different isolates from the same animal. In this review we highlight the key factors that contribute to the accuracy of bacteriological diagnosis of M. bovis and M. caprae, and describe the development of advanced genotyping techniques that are increasingly used in diagnostic laboratories for the purpose of supporting detailed epidemiological investigations. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2 NPs were readily uptaken by A549 cells in vitro. [•] Very low translocation of TiO2 NPs through a differentiated Caco-2 monolayer system. [•] Titanium levels in tissues did not increase after a single oral dose of TiO2 NPs. [•] Several NPs were observed in the cytoplasm of a cell from a Peyer's Patch by TEM. [ABSTRACT FROM AUTHOR]

Posterior reversible encephalopathy syndrome (PRES) is a cliniconeuroradiologic entity characterized by typical neurologic symptoms with characteristic cerebral image alterations. It has been reported in solid organ transplantations, especially related to the use of calcineurin inhibitors. The incidence of PRES in lung transplantation is unknown and probably under-reported in the literature. Here we describe 5 cases of PRES after bilateral lung transplantation. One of the reported cases was the first in the literature in which the neurologic onset precluded the introduction of calcineurin inhibitor. Therefore, although calcineurin inhibitors are known to play an important role in the development of PRES in the setting of lung transplantation, other causes seems to be involved in the physiopathology of this syndrome. [ABSTRACT FROM AUTHOR]

Methodologies for designing maintenance policies, such as Reliability Centered Maintenance (RCM), provide a list of recommended preventive maintenance (PM) activities as well as the periodicity for their execution, to comply with safety and reliability standards. This information is then used to elaborate PM plans, defining the instants of execution of each PM activity in the policy throughout a planning horizon, while assuring adequate levels of equipment availability, labor and resource coordination, and spare parts management. Preferably, it is sought to group PM activities executions to form opportunistic work packages to reduce functionality interruptions on the equipment. To address the latter issue, this paper presents an optimization framework for the medium-term opportunistic planning of PM activities on a single machine. The proposed framework is formulated as a computationally tractable continuous time mixed-integer linear program (MILP) that determines the execution instants of PM activities, considering time window tolerances for advancing or delaying executions to maximize the number of grouped executions or, equivalently, minimizing the number of stoppages needed to comply with a PM policy. Diverse numerical experiments are conducted, considering variants of the model regarding the conservativeness in use of the time window tolerances and the inclusion of resource constraints for planning. The results show that the reductions on the number of stoppages of the PM plans, that can be achieved from different levels of time window tolerances, are more significant for PM policies composed by activities with more heterogeneous periodicities of execution. • The mid-term preventive maintenance planning problem for one machine is addressed. • Opportunistic packages of activities are needed to reduce the number of stoppages. • An efficient continuous time MILP optimization framework is presented. • An extension including resources availability constraints is proposed and studied. • Numerical experiments show substantial savings in the number of stoppages. [ABSTRACT FROM AUTHOR]

Abstract: The survival of several genera of fungi was determined in the ensiled solid fraction of swine faeces after 0, 7, 14, 28 and 56 days of ensiling. The experiment had two treatments, un-ensiled and ensiled manure, in a split-plot design. The manure was distributed into 50 containers; samples, taken at the specified times, were cultured in agar potato dextrose medium, incubated, and colony forming units (CFU/g) were counted and log-transformed. The ensiling process decreased the number of CFU after 56 days. Five fungal genera were identified (Absidia spp., Aspergillus spp., Penicillium spp., Rhizopus spp. and non-fructiferous fungi), and their vulnerability to the ensiling conditions varied, although most of them slowed their growth or disappeared after 14 days of ensiling. [Copyright &y& Elsevier]

The survival and viability of eggs from Ascaris suum and Oesophagostomum dentatum and of infective larvae (L3) from O. dentatum were determined in the ensiled solid fraction of swine faeces after 0, 7, 14, 28 and 56 days of ensiling. The experiment had two treatments, un-ensiled and ensiled manure, in a split-plot design. Each of 50 containers was inoculated with 40,000 eggs of both A. suum and O. dentatum, and another 50 containers were inoculated with 32,747 L3 of O. dentatum each. A. suum eggs were not destroyed by the ensiling process, although their viability was diminished. O. dentatum eggs and larvae were destroyed during the first 7–14 days of the ensiling process. [Copyright &y& Elsevier]

Mucorales is a fungus that causes systemic, highly lethal infections in immunocompromised patients. The overall mortality of pulmonary mucormycosis can reach 95%. This work is a review of medical records of 200 lung transplant recipients between the years of 2003 and 2013, in order to identify the prevalence of Mucorales in the Lung Transplantation service of Heart Institute (InCor), Hospital das Clínicas da Universidade de São Paulo, Brazil, by culture results from bronchoalveolar lavage and necropsy findings. We report 4 cases found at this analyses: 3 in patients with cystic fibrosis and 1 in a patient with bronchiectasis due to Kartagener syndrome. There were 2 unfavorable outcomes related to the presence of Mucorales, 1 by reduction of immunosuppression, another by invasive infection. Another patient died from renal and septic complications from another etiology. One patient was diagnosed at autopsy just 5 days after lung transplantation, with the Mucor inside the pulmonary vein with a precise, well-defined involvement only of donor's segment, leading to previous colonization hypothesis. There are few case reports of Mucorales infection in lung transplantation in the literature. Surveillance for the presence of Mucor can lead to timely fungal treatment and reduce morbidity and mortality in the immunocompromised patients, especially lung transplant recipients. [ABSTRACT FROM AUTHOR]