915 resultados para Ambient pressures


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The synthesis of size-monodispersed indium nanoparticles via an innovative simultaneous phase transfer and ripening method is reported. The formation of nanoparticles occurs in a one-step process instead of well-known two-step phase transfer approaches. The synthesis involves the reduction of InCl3 with LiBH4 at ambient temperature and although the reduction occurs at room temperature, fine indium nanoparticles, with a mean diameter of 6.4 ± 0.4 nm, were obtained directly in non-polar n-dodecane. The direct synthesis of indium nanoparticles in n-dodecane facilitates their fast formation and enhances their size-monodispersity. In addition, the nanoparticles were highly stable for more than 2 months. The nanoparticles were characterised by dynamic light scattering (DLS), small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy to determine their morphology, structure and phase purity.

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Objectives: To discuss how current research in the area of smart homes and ambient assisted living will be influenced by the use of big data. Methods: A scoping review of literature published in scientific journals and conference proceedings was performed, focusing on smart homes, ambient assisted living and big data over the years 2011-2014. Results: The health and social care market has lagged behind other markets when it comes to the introduction of innovative IT solutions and the market faces a number of challenges as the use of big data will increase. First, there is a need for a sustainable and trustful information chain where the needed information can be transferred from all producers to all consumers in a structured way. Second, there is a need for big data strategies and policies to manage the new situation where information is handled and transferred independently of the place of the expertise. Finally, there is a possibility to develop new and innovative business models for a market that supports cloud computing, social media, crowdsourcing etc. Conclusions: The interdisciplinary area of big data, smart homes and ambient assisted living is no longer only of interest for IT developers, it is also of interest for decision makers as customers make more informed choices among today's services. In the future it will be of importance to make information usable for managers and improve decision making, tailor smart home services based on big data, develop new business models, increase competition and identify policies to ensure privacy, security and liability.

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The Iowa Department of Natural Resources (DNR) Ambient Water Monitoring Program provides consistent, unbiased information about the condition of Iowa’s water resources to support decisions affecting the development, management and protection of these resources. To strengthen its services, the program worked with a variety of stakeholders and other DNR programs to develop a five-year strategy for Iowa’s ambient water monitoring efforts. The strategy identifies opportunities to improve the program’s effectiveness in several categories: monitoring objectives, sampling design, data management, products and services, and program evaluation and coordination. Iowa DNR managers and technical staff will use the new strategy to guide decisions affecting the ambient monitoring program over the next five years. The strategy should also serve as a robust informational resource for stakeholders, policy makers, legislators and the public.

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This report summarizes the results of groundwater monitoring that took place from October 2014 - April 2015. Raw, untreated groundwater was sampled from forty-five municipal wells generall characterized as vulnerable to contamination from surface activities. Samples were analyzed for basic water quality parameters, nutrients, atrazine and two of its breakdown products, chloroacetanilide herbicides and their ethanesulfonic and oxanalic acid degradates, and a suite of sixteen pharmaceutical compounds.

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This report summarizes the results of groundwater quality monitoring conducted at 68 public water supply wells in Iowa between October 2015 and March 2016. Raw groundwater samples were analyzed for basic water quality parameters, nutrients, atrazine and its degradates, and chloroacetanilide herbicides and their ethanesulfonic and oxanilic acid degradates. In addition, a subset of samples were analyzed for radionuclides including gross alpha and gross beta radioactivity, radium-226, and radium-228.

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During its history, several significant earthquakes have shaken the Lower Tagus Valley (Portugal). These earthquakes were destructive; some strong earthquakes were produced by large ruptures in offshore structures located southwest of the Portuguese coastline, and other moderate earthquakes were produced by local faults. In recent years, several studies have successfully obtained strong-ground motion syntheses for the Lower Tagus Valley using the finite difference method. To confirm the velocity model of this sedimentary basin obtained from geophysical and geological data, we analysed the ambient seismic noise measurements by applying the horizontal to vertical spectral ratio (HVSR) method. This study reveals the dependence of the frequency and amplitude of the low-frequency (HVSR) peaks (0.2–2 Hz) on the sediment thickness. We have obtained the depth of the Cenozoic basement along a profile transversal to the basin by the inversion of these ratios, imposing constraints from seismic reflection, boreholes, seismic sounding and gravimetric and magnetic potentials. This technique enables us to improve the existing three-dimensional model of the Lower Tagus Valley structure. The improved model will be decisive for the improvement of strong motion predictions in the earthquake hazard analysis of this highly populated basin. The methodology discussed can be applied to any other sedimentary basin.

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To shed light on the potential efficacy of cycling as a testing modality in the treatment of intermittent claudication (IC), this study compared physiological and symptomatic responses to graded walking and cycling tests in claudicants. Sixteen subjects with peripheral arterial disease (resting ankle: brachial index (ABI) < 0.9) and IC completed a maximal graded treadmill walking (T) and cycle (C) test after three familiarization tests on each mode. During each test, symptoms, oxygen uptake (VO2), minute ventilation (VE), respiratory exchange ratio (RER) and heart rate (HR) were measured, and for 10 min after each test the brachial and ankle systolic pressures were recorded. All but one subject experienced calf pain as the primary limiting symptom during T; whereas the symptoms were more varied during C and included thigh pain, calf pain and dyspnoea. Although maximal exercise time was significantly longer on C than T (690 +/- 67 vs. 495 +/- 57 s), peak VO2, peak VE and peak heart rate during C and T were not different; whereas peak RER was higher during C. These responses during C and T were also positively correlated (P < 0.05) with each other, with the exception of RER. The postexercise systolic pressures were also not different between C and T. However, the peak decline in ankle pressures from resting values after C and T were not correlated with each other. These data demonstrate that cycling and walking induce a similar level of metabolic and cardiovascular strain, but that the primary limiting symptoms and haemodynamic response in an individual's extremity, measured after exercise, can differ substantially between these two modes.

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For a largely arid country with generally low relief, Australia has a remarkably large number and variety of waterfalls. Found mainly near the coast, close to where most of the population lives and near the major tourist resort areas, these landscape features have long been popular scenic attractions. As sights to see and places to enjoy a variety of recreational activities, waterfalls continue to play an important role in Australia’s tourism, even in seaside resort areas where the main attractions are sunshine, sandy beaches and surf. The aesthetic appeal of waterfalls and their value as recreational resources are recognized by the inclusion of many in national parks. Even here, demands of visitors and pressures from developers raise serious problems. This paper examines the way in which waterfalls have been developed and promoted as tourist attractions, demonstrating their importance to Australian tourism. It considers threats to the sustainable use of waterfall resources posed by power schemes and, particularly, by the tourist industry itself. Queensland’s Gold Coast is selected as a case study, and comparisons are made with other areas in which waterfalls have played important roles as tourist attractions, especially the Yorkshire coast of northeast England. The discussion draws largely on an examination of tourist literature from the nineteenth to the twenty-first century, including holiday brochures and guide books, as well as other published sources, together with field observation in various parts of the world

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Brucite [Mg(OH)2] microbialites occur in vacated interseptal spaces of living scleractinian coral colonies (Acropora, Pocillopora, Porites) from subtidal and intertidal settings in the Great Barrier Reef, Australia, and subtidal Montastraea from the Florida Keys, United States. Brucite encrusts microbial filaments of endobionts (i.e., fungi, green algae, cyanobacteria) growing under organic biofilms; the brucite distribution is patchy both within interseptal spaces and within coralla. Although brucite is undersaturated in seawater, its precipitation was apparently induced in the corals by lowered pCO2 and increased pH within microenvironments protected by microbial biofilms. The occurrence of brucite in shallow-marine settings highlights the importance of microenvironments in the formation and early diagenesis of marine carbonates. Significantly, the brucite precipitates discovered in microenvironments in these corals show that early diagenetic products do not necessarily reflect ambient seawater chemistry. Errors in environmental interpretation may arise where unidentified precipitates occur in microenvironments in skeletal carbonates that are subsequently utilized as geochemical seawater proxies.

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The specific mechanisms by which selective pressures affect individuals are often difficult to resolve. In tephritid fruit flies, males respond strongly and positively to certain plant derived chemicals. Sexual selection by female choice has been hypothesized as the mechanism driving this behaviour in certain species, as females preferentially mate with males that have fed on these chemicals. This hypothesis is, to date, based on studies of only very few species and its generality is largely untested. We tested the hypothesis on different spatial scales (small cage and seminatural field-cage) using the monophagous fruit fly, Bactrocera cacuminata. This species is known to respond to methyl eugenol (ME), a chemical found in many plant species and one upon which previous studies have focused. Contrary to expectation, no obvious female choice was apparent in selecting ME-fed males over unfed males as measured by the number of matings achieved over time, copulation duration, or time of copulation initiation. However, the number of matings achieved by ME-fed males was significantly greater than unfed males 16 and 32 days after exposure to ME in small cages (but not in a field-cage). This delayed advantage suggests that ME may not influence the pheromone system of B. cacuminata but may have other consequences, acting on some other fitness consequence (e.g., enhancement of physiology or survival) of male exposure to these chemicals. We discuss the ecological and evolutionary implications of our findings to explore alternate hypotheses to explain the patterns of response of dacine fruit flies to specific plant-derived chemicals.

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Titanium dioxide nanocrystals are an important commercial product used primarily in white pigments and abrasives, however, more recently the anatase form of TiO2 has become a major component in electrochemical and photoelectrochemical devices. An important property of titanium dioxide nanocrystals for electrical applications is the degree of crystallinity. Numerous preparation methods exist for the production of highly crystalline TiO2 particles. The majority of these processes require long reaction times, high pressures and temperatures (450–1400 °C). Recently, hydrothermal treatment of colloidal TiO2 suspensions has been shown to produce quality crystalline products at low temperatures (<250 °C). In this paper we extend this idea utilising a direct microwave heating source. A comparison between convection and microwave hydrothermal treatment of colloidal TiO2 is presented. The resulting highly crystalline TiO2 colloids were characterised using Raman spectroscopy, XRD, TEM, and electron diffraction. The results show that the microwave treatment of colloidal TiO2 gives comparable increases in crystallinity with respect to normal hydrothermal treatments while requiring significantly less time and energy than the hydrothermal convection treatment.

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Air pollution levels were monitored continuously over a period of 4 weeks at four sampling sites along a busy urban corridor in Brisbane. The selected sites were representative of industrial and residential types of urban environment affected by vehicular traffic emissions. The concentration levels of submicrometer particle number, PM2.5, PM10, CO, and NOx were measured 5-10 meters from the road. Meteorological parameters and traffic flow rates were also monitored. The data were analysed in terms of the relationship between monitored pollutants and existing ambient air quality standards. The results indicate that the concentration levels of all pollutants exceeded the ambient air background levels, in certain cases by up to an order of magnitude. While the 24-hr average concentration levels did not exceed the standard, estimates for the annual averages were close to, or even higher than the annual standard levels.

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Traffic emissions are an important contributor to ambient air pollution, especially in large cities featuring extensive and high density traffic networks. Bus fleets represent a significant part of inner city traffic causing an increase in exposure to general public, passengers and drivers along bus routes and at bus stations. Limited information is available on quantification of the levels, and governing parameters affecting the air pollution exposure at bus stations. The presented study investigated the bus emissions-dominated ambient air in a large, inner city bus station, with a specific focus on submicrometer particles. The study’s objectives were (i) quantification of the concentration levels; (ii) characterisation of the spatio-temporal variation; (iii) identification of the parameters governing the emissions levels at the bus station and (iv) assessment of the relationship between particle concentrations measured at the street level (background) and within the bus station. The results show that up to 90% of the emissions at the station are ultrafine particles (smaller than 100 nm), with the concentration levels up to 10 times the value of urban ambient air background (annual) and up to 4 times the local ambient air background. The governing parameters affecting particle concentration at the station were bus flow rate and meteorological conditions (wind velocity). Particle concentration followed a diurnal trend, with an increase in the morning and evening, associated with traffic rush hours. Passengers’ exposure could be significant compared to the average outdoor and indoor exposure levels.