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991.
Rui P. Matos Paulo L. Pinto Carlos S. Rebelo Helena S. Gervásio Milan Veljkovic 《Structure and Infrastructure Engineering》2016,12(9):1038-1050
The constant increase in the wind power production leads to the need of higher wind towers, which brings up some questions regarding the effectiveness of tubular towers and respective foundations. This work focuses on the comparative structural design, life cycle behaviour and costs of onshore concrete shallow foundations for tubular wind towers (WT) when steel micropiles are used to improve resistance of the soil–structure interface (hybrid foundation). Typical wind loading for Turbine Class II and moderate seismicity (.25 g peak ground acceleration) is used to design and analyse 18 WT foundation case studies. This allows the comparison between shallow and hybrid foundations designed for three different hub heights and respective turbine rated power (80 m/2 MW, 100 m/3.6 MW and 150 m/5 MW) and for three different tubular tower solutions (steel, concrete and hybrid steel–concrete). The possible benefits of the solution using steel grouted micropiles are discussed in terms of potential environmental and economic impacts using life cycle analysis. The use of micropiles reveals to be an interesting solution to improve common shallow WT foundations since it allows the reduction of the dimensions of the foundation leading to significant environmental and cost benefits. 相似文献
992.
Xu Y Gong F Dixon SJ Brereton RG Soini HA Novotny MV Oberzaucher E Grammer K Penn DJ 《Analytical chemistry》2007,79(15):5633-5641
The majority of works in metabolomics employ approaches based on principal components analysis (PCA) and partial least-squares, primarily to determine whether samples fall within large groups. However, analytical chemists rarely tackle the problem of individual fingerprinting, and in order to do this effectively, it is necessary to study a large number of small groups rather than a small number of large groups and different approaches are required, as described in this paper. Furthermore, many metabolomic studies on mammals and humans involve analyzing compounds (or peaks) that are present in only a certain portion of samples, and conventional approaches of PCA do not cope well with sparse matrices where there may be many 0s. There is, however, a large number of qualitative similarity measures available for this purpose that can be exploited via principal coordinates analysis (PCO). It can be shown that PCA scores are a specific case of PCO scores, using a quantitative similarity measure. A large-scale study of human sweat consisting of nearly 1000 gas chromatography/mass spectrometry analyses from the sweat of an isolated population of 200 individuals in Carinthia (Southern Austria) sampled once per fortnight over 10 weeks was employed in this study and grouped into families. The first step was to produce a peak table requiring peak detection, alignment, and integration. Peaks were reduced from 5080 to 373 that occurred in at least 1 individual over 4 out of 5 fortnights. Both qualitative (presence/absence) and quantitative (equivalent to PCA) similarity measures can be computed. PCO and the Kolomorogov-Smirnoff (KS) rank test are applied to these similarity matrices. It is shown that for this data set there is a reproducible individual fingerprint, which is best represented using the qualitative similarity measure as assessed both by the Hotelling t2 statistic as applied to PCO scores and the probabilities associated with the KS rank test. 相似文献
993.
Almeida JF Fonseca A Baptista CM Leite E Gil MH 《Journal of materials science. Materials in medicine》2007,18(12):2309-2317
Recently there have been some developments in the preparation of controlled drug delivery systems for glaucoma. Many materials
are being used in this area, namely gelatine and chitosan. Both of them present high levels of biocompatibility and biodegradability.
In this paper, we wish to report the work we have been doing on the preparation and characterization of hydrogels based on
gelatine and chitosan. The crosslinking agents used were 1-(3-(Dimethylamino)propyl)-3-Ethylcarbodiimide hydrocholide (CDI),
1,4-Butanodiol diglycidyl ether (epoxyde 1), Ethylene glycol diglycidyl ether (epoxyde 2) and genipin. The results obtained
showed that all of the films were hydrogels. The surface and transversal cut showed a porous surface in all the films. The
thermal analysis proved the modifications in the polymeric chains, with the stabilization of all of them by the crosslinking
agents. The release pattern indicates that the gelatine films were the best since they release the adequate proportion of
drug. Finally, the cytotoxicity showed that the gelatine films were all biocompatible, specially the ones crosslinked with
one of the Epoxydes. 相似文献
994.
Kaper H Endres F Djerdj I Antonietti M Smarsly BM Maier J Hu YS 《Small (Weinheim an der Bergstrasse, Germany)》2007,3(10):1753-1763
The direct synthesis of crystalline titania nanorods by sol-gel chemistry in a special ionic liquid is reported. Unexpectedly, the high-temperature modification, rutile, is obtained directly under ambient conditions. X-ray diffraction and high-resolution transmission electron microscopy measurements support the highly crystalline and structural quality of the sample. The phase-directing property of the ionic liquids is attributable to the imide group in the counter ion, which exhibits strong interaction with specific rutile faces. Lithium insertion experiments were performed and revealed high and reversible loading capacities of up to 200 mAh g(-1). 相似文献
995.
Italo José B. Durval Ana Helena M. Resende Mariana A. Figueiredo Juliana M. Luna Raquel D. Rufino Leonie A. Sarubbo 《Journal of surfactants and detergents》2019,22(2):349-363
With the aim of producing a biotensioactive material for use in the remediation of marine environments, screening for biosurfactant-producing bacteria was conducted with strains isolated from seawater contaminated with petroleum derivatives. Gene sequencing revealed that all four promising biosurfactant-producing isolates belonged to the same genus and species, namely Bacillus cereus. The biosurfactant-producing bacteria were cultivated with different carbon (glucose, soybean oil, and waste frying soybean oil) and nitrogen (ammonium chloride, sodium nitrate, urea, and peptone) sources. B. cereus strain BCS0 was chosen as the best biosurfactant producer in a mineral medium with 2% frying oil and 0.12% peptone. Following the optimization of agitation and cultivation time, an agitation rate of 250 rpm and 48 h of cultivation were selected. Under these conditions, the surface tension was reduced to 27 mN m−1 and the biosurfactant concentration was 3.5 g L−1. The critical micelle concentration (CMC) of the biosurfactant was defined as 500 mg L−1. The biosurfactant remained stable within large ranges of pH (2–10), salinity (2–10%), and temperature (5–120 °C). Under these conditions, motor oil emulsification rates were greater than 90%. Moreover, the biosurfactant properties remained unaltered after heating at 90 °C for 120 min. The biosurfactant enhanced the degradation of motor oil up to 96% in 27 days and exhibited considerable motor oil displacement capacity. Thus, the biosurfactant has potential in the application of remediation processes in marine environments. 相似文献
996.
Channon Shelley; Drury Helena; Martinos Marina; Robertson Mary M.; Orth Mike; Crawford Sarah 《Canadian Metallurgical Quarterly》2009,23(3):359
Tourette’s syndrome (TS) is a neurodevelopmental disorder linked with frontostriatal dysfunction. Previous work has shown some evidence of mild performance deficits on a range of different tasks that involve inhibitory processes. The present study evaluated this in adult participants with uncomplicated TS. Interference control was measured using the Stroop and flanker tasks and a Stroop–flanker task that combined the inhibitory demands of both. Motor inhibition was measured using a letter continuous performance test (CPT) task and word CPT tasks that manipulated the inhibitory demands using compatible and incompatible words. The TS group was found to be slower than the control group on most measures, but showed differential slowing under conditions with enhanced inhibitory demands on the combined Stroop–flanker and the incompatible CPT tasks. The findings suggest that TS-alone is linked to mild impairments in aspects of inhibitory function, and that these can be detected by relatively powerful inhibitory manipulations. A range of different types of inhibitory tasks may be sensitive to TS-alone, and this may depend on both the type of inhibition and the strength of the inhibitory manipulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
997.
In water supply systems there are many situations during normal operation that induce the occurrence of pressure transients,
where high pressures are followed by low, sometimes even negative pressures. These transients may cause ruptures in pipes
creating thus leaks or opportunities for contaminants to enter the water supply system. Thus severe pressures transients should
be avoided or adequately controlled in potable drinking systems. The level of service provided by water distribution systems
is an important matter in the water industry of today. However, the measure of the performance of a pipe system network is
not a straightforward task. In this study the performance of pressures in two networks (a cast iron network and a polyethylene
network) with the same typology was compared. The transient state conditions were induced by different typical hydromechanical
devices operation characterised by a sudden pumps trip-off, a leakage occurrence and a closure of an automatic control valve.
For the hydraulic simulations, advanced models based on numerical computation for steady and transient state conditions were
used. A performance evaluation model was developed to analyse each type of situation since the simulation time period and
the concerns regarding the system behaviour can be fairly different. 相似文献
998.
This work investigates the potential of Rubus ulmifolius, indigenous to a metal contaminated site--Esteiro de Estarreja--for phytoremediation purposes. The site has a long history of metal contamination. The accumulation of lead (Pb), arsenic (As) and nickel (Ni) in different sections--roots, stems and leaves - of the plant was assessed and compared to the levels of those metals in the soil and in the available fraction. The distribution of metals throughout the area was quite heterogeneous, presenting levels of As, Pb and Ni of up to 3078, 1400 and 135 mg kg(-1), respectively, and the metal content in the sections of R. ulmifolius collected in the banks of the stream varied among sites of collection. Levels of metals were higher in the plant roots: As levels (mgkg(-1)) ranged from 277 to 1721 in the roots, 30 to 110 in the stems, and 60 to 265 in the leaves; Pb concentrations (mgkg(-1)) ranged from 248 to 1178 in the roots, 35 to 133 in the stems, and 25 to 149 in the leaves; and Ni (mgkg(-1)) ranged from 48 to 151 in the roots. Significant correlations were found between the total levels of Pb and As in the soil and the levels in the roots of the plant; further correlations between total and available levels in the soil and metals in other plant tissues were generally found as non-significant. According to the metal accumulation patterns of R. ulmifolius, this species seems to be valuable for application in phytostabilisation strategies. 相似文献
999.
Leandro de Morais Cardoso Soraia Silva Pinheiro Hércia Stampini Duarte Martino Helena Maria Pinheiro-Sant'Ana 《Critical reviews in food science and nutrition》2017,57(2):372-390
Sorghum is the fifth most produced cereal in the world and is a source of nutrients and bioactive compounds for the human diet. We summarize the recent findings concerning the nutrients and bioactive compounds of sorghum and its potential impact on human health, analyzing the limitations and positive points of the studies and proposing directions for future research. Sorghum is basically composed of starch, which is more slowly digested than that of other cereals, has low digestibility proteins and unsaturated lipids, and is a source of some minerals and vitamins. Furthermore, most sorghum varieties are rich in phenolic compounds, especially 3-deoxyanthocyanidins and tannins. The results obtained in vitro and in animals have shown that phenolics compounds and fat soluble compounds (polycosanols) isolated from sorghum benefit the gut microbiota and parameters related to obesity, oxidative stress, inflammation, diabetes, dyslipidemia, cancer, and hypertension. The effects of whole sorghum and its fractions on human health need to be evaluated. In conclusion, sorghum is a source of nutrients and bioactive compounds, especially 3-deoxyanthocyanidins, tannins, and polycosanols, which beneficially modulate, in vitro and in animals, parameters related to noncommunicable diseases. Studies should be conducted to evaluate the effects of different processing on protein and starch digestibility of sorghum as well as on the profile and bioavailability of its bioactive compounds, especially 3-deoxyanthocyanidins and tannins. Furthermore, the benefits resulting from the interaction of bioactive compounds in sorghum and human microbiota should be studied. 相似文献
1000.
Prebiotic Low Sugar Chocolate Dairy Desserts: Physical and Optical Characteristics and Performance of PARAFAC and PCA Preference Map
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E. C. Morais E. A. Esmerino R. A. Monteiro C. M. Pinheiro C. A. Nunes A.G. Cruz Helena M.A. Bolini 《Journal of food science》2016,81(1):S156-S164
The addition of prebiotic and sweeteners in chocolate dairy desserts opens up new opportunities to develop dairy desserts that besides having a lower calorie intake still has functional properties. In this study, prebiotic low sugar dairy desserts were evaluated by 120 consumers using a 9‐point hedonic scale, in relation to the attributes of appearance, aroma, flavor, texture, and overall liking. Internal preference map using parallel factor analysis (PARAFAC) and principal component analysis (PCA) was performed using the consumer data. In addition, physical (texture profile) and optical (instrumental color) analyses were also performed. Prebiotic dairy desserts containing sucrose and sucralose were equally liked by the consumers. These samples were characterized by firmness and gumminess, which can be considered drivers of liking by the consumers. Optimization of the prebiotic low sugar dessert formulation should take in account the choice of ingredients that contribute in a positive manner for these parameters. PARAFAC allowed the extraction of more relevant information in relation to PCA, demonstrating that consumer acceptance analysis can be evaluated by simultaneously considering several attributes. Multiple factor analysis reported Rv value of 0.964, suggesting excellent concordance for both methods. 相似文献