855 resultados para Géis de silicone
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Electrospinning was used to generate polymer nanofibres from blends of poly-vinyl cinnamate (PVCN) and a cholesteric silicone polymer. Only blends that contained at least 40 % of PVCN produced fibres. Both differential scanning calorimetry and electron dispersion spectroscopy data indicate that the samples are miscible over a wide temperature interval. The variation of fibre diameter with concentration is nonlinear with a well-defined minimum corresponding to an 80 % PVCN blend. The fibres are birefringent with Kerr constants similar to that of cholesteric liquid crystals. Although not significant, the Kerr constant increases with increasing silicone polymer concentration.
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This paper presents a GIS-based multicriteria flood risk assessment and mapping approach applied to coastal drainage basins where hydrological data are not available. It involves risk to different types of possible processes: coastal inundation (storm surge), river, estuarine and flash flood, either at urban or natural areas, and fords. Based on the causes of these processes, several environmental indicators were taken to build-up the risk assessment. Geoindicators include geological-geomorphologic proprieties of Quaternary sedimentary units, water table, drainage basin morphometry, coastal dynamics, beach morphodynamics and microclimatic characteristics. Bioindicators involve coastal plain and low slope native vegetation categories and two alteration states. Anthropogenic indicators encompass land use categories properties such as: type, occupation density, urban structure type and occupation consolidation degree. The selected indicators were stored within an expert Geoenvironmental Information System developed for the State of Sao Paulo Coastal Zone (SIIGAL), which attributes were mathematically classified through deterministic approaches, in order to estimate natural susceptibilities (Sn), human-induced susceptibilities (Sa), return period of rain events (Ri), potential damages (Dp) and the risk classification (R), according to the equation R=(Sn.Sa.Ri).Dp. Thematic maps were automatically processed within the SIIGAL, in which automata cells (""geoenvironmental management units"") aggregating geological-geomorphologic and land use/native vegetation categories were the units of classification. The method has been applied to the Northern Littoral of the State of Sao Paulo (Brazil) in 32 small drainage basins, demonstrating to be very useful for coastal zone public politics, civil defense programs and flood management.
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Systemic inflammation after augmentation mammaplasty with modern silicone implants is not currently recognized. In a prospective controlled study, C-reactive protein and other variables were monitored, aiming to test this hypothesis in a young cohort of patients. Females (18-30 years old, BMI = 18.5-30 kg/m(2), N = 52) were consecutively recruited for breast implant (n = 24, Group I) and for abdominal liposuction (n = 28, Group II/Controls). Patients were interviewed at baseline and followed until 6 months after operation. Variables included demographic and clinical information, surgical outcome, inflammatory markers and autoantibodies. Operations were well tolerated, without surgical or infectious complications. Mean prosthesis size was 258 +/- A 21 ml (range = 220-280) and mean aspirate of liposuction was 1972 +/- A 499 ml (range = 1200-3000). Preoperative, 2-month, and 6-month C-reactive protein concentrations for breast implant patients were 1.3 +/- A 1.2, 4.8 +/- A 3.0, and 4.3 +/- A 6.4 mg/l and for liposuction 3.5 +/- A 2.7, 3.5 +/- A 2.1, and 2.2 +/- A 2.2 mg/l, respectively. Change at 2 months was significant (p = 0.001). Autoantibody investigation failed to reveal remarkable aberrations, except for anticardiolipin elevation, which was nearly symmetrical in the two groups. C-reactive protein levels increased after operation and correlated with proinflammatory and procoagulatory indices. A mild increase in anticardiolipin IgM occurred but differences between populations were lacking. Despite excellent cosmetic outcomes and lack of complications, acute phase reaction could signal ongoing immunogenicity of silicone and long-term monitoring is recommended.
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This paper presents the groundwater favorability mapping on a fractured terrain in the eastern portion of Sao Paulo State, Brazil. Remote sensing, airborne geophysical data, photogeologic interpretation, geologic and geomorphologic maps and geographic information system (GIS) techniques have been used. The results of cross-tabulation between these maps and well yield data allowed groundwater prospective parameters in a fractured-bedrock aquifer. These prospective parameters are the base for the favorability analysis whose principle is based on the knowledge-driven method. The mutticriteria analysis (weighted linear combination) was carried out to give a groundwater favorabitity map, because the prospective parameters have different weights of importance and different classes of each parameter. The groundwater favorability map was tested by cross-tabulation with new well yield data and spring occurrence. The wells with the highest values of productivity, as well as all the springs occurrence are situated in the excellent and good favorabitity mapped areas. It shows good coherence between the prospective parameters and the well yield and the importance of GIS techniques for definition of target areas for detail study and wells location. (c) 2008 Elsevier B.V. All rights reserved.
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Composite electrodes were prepared using graphite powder and silicone rubber in different compositions. The use of such hydrophopic materials interned to diminish the swallowing observed in other cases when the electrodes are used in aqueous solutions for a long time. The composite was characterized for the response reproducibility, ohmic resistance, thermal behavior and active area. The voltammetric response in relation to analytes with known voltammetric behavior was also evaluated, always in comparison with the glassy carbon. The 70% (graphite, w/w) composite electrode was used in the quantitative determination of hydroquinone (HQ) in a DPV procedure in which a detection limit of 5.1 x 10(-8) mol L-1 was observed. HQ was determined in a photographic developer sample with errors lower then 1% in relation to the label value. (c) 2007 Elsevier B.V. All rights reserved.
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A graphite silicone-rubber composite electrode (GSR) was used for the determination of propranolol in drug formulation. Cyclic voltammetry (CV) at the GSR presented an irreversible oxidation peak at + 0.8V vs. SCE, in Britton Robinson (B-R) buffer pH 7.4. The quantitative determination was carried out using differential pulse voltammetry (DPV). Under optimized parameters a linear dynamic range from 5.0 to 80.6 mu mol L(-1) with a detection limit of 1.1 mu mol L(-1) was observed. A repeatability of 4.5 +/- 0.1 mu A (n = 10) peak current was found after 10 successive DPV voltammograms of propranolol in the same solution after surface renovations. Using the proposed electrode, propranolol was quantified in a pharmaceutical formulation with results that agreed within 95% confidence level (t-test) with those from an official method.
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A new composite electrode based on multiwall carbon nanotubes (MWCNT) and silicone-rubber (SR) was developed and applied to the determination of propranolol in pharmaceutical formulations. The effect of using MWCNT/graphite mixtures in different proportions was also investigated. Cyclic voltammetry and electrochemical impedance spectroscopy were used for electrochemical characterization of different electrode compositions. Propranolol was determined using MWCNT/SR 70% (m/m) electrodes with linear dynamic ranges up to 7.0 mu molL(-1) by differential pulse and up to 5.4 mu molL(-1) by square wave voltammetry, with LODs of 0.12 and 0.078 mu molL(-1), respectively. Analysis of commercial samples agreed with that obtained by the official spectrophotometric method. The electrode is mechanically robust and presented reproducible results and a long useful life.
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Denna rapport presenterar ett examensarbete på D-nivå där uppdragsgivaren har varit WM-data Consulting och kunden Vägverket Produktion.Vägverket har ett antal olika applikationer för geografisk information som ligger utspridda på företagets hemsida . För att samla alla applikationer på ett och samma ställe fick vi i uppdrag att göra en grundläggande utredning av en GIS-portal. Denna portal ska fungera som en enhetlig ingång där kartdata samkörs och visualiseras. Ytterligare en del i uppdraget var att utreda vad som borde förändras och förbättras i den redan existerande tjänsten Beläggning på vägarna. Denna tjänst kommer att fungera som en testapplikation för GIS-portalen.Målen med examensarbetet var att utreda vilka krav som finns på en GIS-portal och applikationen Beläggning på vägarna samt att beskriva de önskemål som finns på dessa. Ett designförslag och en funktionsbeskrivning arbetades fram för både tjänsten Beläggning på vägarna och för GIS-portalen. Utredningen kommer att ligga till grund för utveckling av en GIS-portal samt fortsatt utveckling och förbättringar av tjänsten Beläggning på vägarna.För att komma fram till ett resultat har vi använt oss av ett antal teorier om IT-tjänster, systemarkitektur och användbarhet. Förutom dessa teorier har även de intervjuer som utförts spelat en stor roll för vårt arbete. Vi har lagt en bra grund för Vägverket att fortsätta arbetet med utveckling av en GIS-portal och tjänsten Beläggning på vägarna.
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I studien har gymnasielärares didaktiska val för implementering av geografiska informationssystem (GIS) i geografiundervisningen undersökts. Resultatet baseras på intervjuer med sex stycken respondenter, vilka har framhållit sina erfarenheter, tillämpnings- och förhållningssätt till GIS. De slutsatser som framkommer är att respondenterna enbart använder webbaserade och kostnadsfria GIS-program i undervisningen. I dessa tillämpas GIS som ett verktyg för att behandla olika frågor i undervisningen, och därmed är det undervisning, med hjälp av GIS, som karakteriserar respondenternas användning. De didaktiska valen behandlar naturgeografiska förhållanden, såsom landformer. Vissa respondenter använder också GIS till att behandla frågor med utgångspunkt i kulturgeografiska förhållanden, till exempel olika typer av befolkningsfrågor. Att arbeta tvärvetenskapligt i GIS, således mot ämnets två vetenskapliga discipliner, är inte karakteristiskt för alla respondenter. Dessutom använder ett fåtal respondenter fortfarande kartboken, eller låter eleverna rita kartor för hand. Nästan alla respondenter anser att de vill, och behöver, öka användningen av GIS i och med utformningen av de nya kursplanerna för geografiämnet i Gy11. Emellertid hämmas respondenternas möjligheter att undervisa i geografiska informationssystem av en kombination av brist på tid, resurser och kunskap.
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The word “wilderness” in America is generally identified with pristine places where humans are not among the primary influences on the land and its ecology. The American wilderness ethic creates a strict dichotomy between humans and nature. The Wilderness Preservation Act of 1964 defines wilderness as “an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain” (wilderness.net). This statutory definition of wilderness is essentially the functional embodiment of the American wilderness ethic. Wilderness can also be interpreted in ways that incorporate humans as active players in the natural world. Land which is managed for human use but is uninhabited can be considered wilderness to some degree because “man himself is a visitor who does not remain.” Wilderness, especially in the Northeast, can be visualized based on different land use characteristics. Conservation in the Northeast requires a redefinition of wilderness in order to incorporate land that has been utilized by humans.
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http://digitalcommons.colby.edu/atlasofmaine2008/1021/thumbnail.jpg
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http://digitalcommons.colby.edu/atlasofmaine2006/1017/thumbnail.jpg
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http://digitalcommons.colby.edu/atlasofmaine2005/1024/thumbnail.jpg
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The range of the Gray Wolf (Canis lupus), once covering most of North America, has been drastically reduced by an estimated 95% due to habitat loss and extermination by humans. The wolf was extirpated from Maine in the 1800’s. Wolf reintroductions have been suggested for Maine, but there is some debate about how much land is suitable for wolves. I developed a wolf habitat suitability analysis using ArcGIS and data from the Maine Office of GIS and the United States National Atlas. The model incorporates land cover, presence of major roads and railways, conservation land, industrial, non-industrial, and public woodlot ownership, distance from major points of population, deer population, and slope. The model results show areas of high and low wolf suitability in Maine. The model suggests that the best potential habitat for wolves in Maine is situated in the northwest of the state. Possible future reintroductions or natural colonization from other areas would have the highest likelihood of survival in these areas.