The exploitation of offshore wind resources is considered to have considerable potential in providing carbon-free energy. To increase the economic viability of wind farms, improvement in power ...generation is sought by mitigating the wake losses. While the industrial standards still favour turbine-level power maximization, the concept of collaborative yaw-based plant-level control has gained significant attention in recent years. The present work investigates the potential of such a wind farm control strategy employing different wake deficit models, for a range of atmospheric conditions and plant layouts. The utilized wake velocity deficit models are the top-hat Jensen model, the Gaussian-shaped Bastankhah model and its novel extension, termed Gauss–Curl Hybrid model, which accounts for secondary steering effects. The yaw control optimization is conducted on a row of eight NREL 5-MW turbines using the FLORIS modelling utility and the SLSQP optimization algorithm. Generally speaking, the Jensen model shows a lack of robustness and is not recommended for yaw control studies. In contrast, the two Gaussian-shaped models are well handled by the optimization algorithm and produce consistent results. More specifically, the Bastankhah model prefers yaw offsets of nearly equal magnitude throughout the whole wind farm except for the most downstream machine that remains aligned with the freestream. On the other hand, the GCH model suggests a large offset at the most upstream turbine, which is gradually reduced at consecutive machines. For the reference wind farm considered, the total power improvement was 3.59% and 14.66% for the Bastankhah and GCH models, respectively.
•A consistent and holistic analysis of the wind farm yield maximization challenge, assessing the impact of distinct wake deficit models and a range of wind farm layouts and atmospheric conditions.•The Jensen model is not recommended for such studies whereas the other two models produce consistent results. Generally speaking the GCH model provided the larger yield improvements.•For reference conditions and compared to baseline control, a farm power improvement of 3.59% and 14.66% was obtained for the Bastankhah and GCH models, respectively..•The Bastankhah model prefers yaw offsets of nearly equal magnitude throughout the whole wind farm whereas the GCH model suggests a large offset at the most upstream turbine, which is gradually reduced at consecutive machines.
We present 32 epochs of optical (3300−9700 Å) spectrophotometric observations of the nearby quintessential “normal” type Ia supernova (SN Ia) SN 2011fe in the galaxy M101, extending from −15 to +97 d ...with respect to B-band maximum, obtained by the Nearby Supernova Factory collaboration. SN 2011fe is the closest (μ = 29.04) and brightest (Bmax = 9.94 mag) SN Ia observed since the advent of modern large scale programs for the intensive periodic followup of supernovae. Both synthetic light curve measurements and spectral feature analysis attest to the normality of SN 2011fe. There is very little evidence for reddening in its host galaxy. The homogeneous calibration, intensive time sampling, and high signal-to-noise ratio of the data set make it unique. Thus it is ideal for studying the physics of SN Ia explosions in detail, and for furthering the use of SNe Ia as standardizable candles for cosmology. Several such applications are shown, from the creation of a bolometric light curve and measurement of the 56Ni mass, to the simulation ofdetection thresholds for unburned carbon, direct comparisons with other SNe Ia, and existing spectral templates.
Chiral Spin-Orbital Liquids with Nodal Lines Natori, W M H; Andrade, E C; Miranda, E ...
Physical review letters,
2016-Jul-01, 2016-7-00, 20160701, Letnik:
117, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Strongly correlated materials with strong spin-orbit coupling hold promise for realizing topological phases with fractionalized excitations. Here, we propose a chiral spin-orbital liquid as a stable ...phase of a realistic model for heavy-element double perovskites. This spin liquid state has Majorana fermion excitations with a gapless spectrum characterized by nodal lines along the edges of the Brillouin zone. We show that the nodal lines are topological defects of a non-Abelian Berry connection and that the system exhibits dispersing surface states. We discuss some experimental signatures of this state and compare them with properties of the spin liquid candidate Ba_{2}YMoO_{6}.
Escherichia coli are believed to be associated with postpartum metritis and endometritis but their role in the pathogenesis of both diseases is still undefined. In this study, uterine swabs for E. ...coli isolation were collected from 374 lactating Holstein cows housed on 4 commercial farms near Ithaca, New York. A total, 125 of 374 cows (33.4%) were positive for E. coli culture. Standard multiplex PCR protocols were used to screen the isolates for the presence of 32 virulence factor genes. Cows that had twin parturition were 4.4 times more likely to have intrauterine E. coli contamination than those that gave birth to single live female calves. Stillborn parturition and birth of single live male calves also increased the odds of intrauterine contamination by E. coli (3.7- and 1.6-fold, respectively) compared with birth of live female calves. Six virulence factors, common to extraintestinal and enteroaggregative E. coli, were found to be associated with metritis and endometritis: fimH, hlyA, cdt, kpsMII, ibeA, and astA. The virulence factor gene fimH was the most prevalent and the most significant: intrauterine E. coli carrying fimH and at least 1 of the other 5 identified virulence factors were pathogenic, and phylogenetic analysis based on the nucleotide sequence of DNA gyrase from 41 such IUEC revealed 2 clades.
Resistance mechanisms and heterogeneity in HER2-positive gastric cancers (GC) limit Trastuzumab benefit in 32% of patients, and other targeted therapies have failed in clinical trials. Using patient ...samples, patient-derived xenografts (PDXs), partially humanized biological models, and HER2-targeted imaging technologies we demonstrate the role of caveolin-1 (CAV1) as a complementary biomarker in GC selection for Trastuzumab therapy. In retrospective analyses of samples from patients enrolled on Trastuzumab trials, the CAV1-high profile associates with low membrane HER2 density and low patient survival. We show a negative correlation between CAV1 tumoral protein levels - a major protein of cholesterol-rich membrane domains - and Trastuzumab-drug conjugate TDM1 tumor uptake. Finally, CAV1 depletion using knockdown or pharmacologic approaches (statins) increases antibody drug efficacy in tumors with incomplete HER2 membranous reactivity. In support of these findings, background statin use in patients associates with enhanced antibody efficacy. Together, this work provides preclinical justification and clinical evidence that require prospective investigation of antibody drugs combined with statins to delay drug resistance in tumors.
The purpose of this study was to investigate the effect of a 12-month Balance Training Program on balance, mobility and falling frequency in women with osteoporosis.
Sixty-six consecutive elderly ...women were selected from the Osteometabolic Disease Outpatient Clinic and randomized into 2 groups: the 'Intervention', submitted for balance training; and the 'Control', without intervention. Balance, mobility and falling frequency were evaluated before and at the end of the trial, using the Berg Balance Scale (BBS), the Clinical Test Sensory Interaction Balance (CTSIB) and the Timed "Up & Go" Test (TUGT). Intervention used techniques to improve balance consisting of a 1-hour session each week and a home-based exercise program.
Sixty women completed the study and were analyzed. The BBS difference was significant higher in the Intervention group compared to Control (5.5 +/- 5.67 vs -0.5 +/- 4.88 score, p<0.001). Similarly, the number of patients in the Intervention group presented improvement in two conditions of CTSIB compared to Control (eyes closed and unstable surface condition: 13 vs one patient, p < 0.001 and eyes open, visual conflict and unstable surface condition: 12 vs one patient, p<0.001). Additionally, the differences between the TUGT were reduced in the Intervention group compared to Control (-3.65 +/- 3.61 vs 2.27 +/- 7.18 seconds, p< 0.001). Notably, this improvement was paralleled by a reduction in the number of falls/patient in the Intervention group compared to Control (-0.77 +/- 1.76 vs 0.33 +/- 0.96, p=0.018).
This longitudinal prospective study demonstrated that an intervention using balance training is effective in improving functional and static balance, mobility and falling frequency in elderly women with osteoporosis.
► Feedstock type and pyrolysis conditions influence the degree of biochar carbonisation. ► Intrinsic lability of biochar revealed via spectroscopic and thermogravimetric analysis. ► Wet oxidation ...provided qualitative and quantitative information on biochar lability. ► C evolved as CO
2 from biochar-amended soil after 110
h was related to carbonisation degree.
Different analytical techniques were used to find the most reliable and economic method for determining the labile fraction of C in biochar. Biochar was produced from pine, poplar and willow (PI, PO and WI, respectively) at two temperatures (400 and 550
°C) and characterised using spectroscopic techniques solid state
13C nuclear magnetic resonance spectroscopy (NMR), molecular markers pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS), thermogravimetry (TG), elemental composition and wet oxidation (potassium permanganate and potassium dichromate). Short term incubation (110
h) of an A horizon from an Umbrisol amended with the biochar samples at two doses (7.5 and 15
t
ha
−1) was also carried out to provide supplementary information on the influence of biochar–soil interaction on CO
2 evolution. Spectroscopic analysis demonstrated that the degree of biochar carbonisation was influenced by the type of feedstock and heating conditions and followed the order WI-400
<
PI-400
∼
WI-550
∼
PO-400
<
PO-550
<
PI-550. The thermo-labile fraction of the biochar samples, estimated from TG, ranged between 21% and 49%. The fraction of total C oxidised with potassium permanganate (C
per/C
total) was <50
g
kg
−1 in all cases, whereas potassium dichromate (C
dichro/C
total) oxidation efficiency ranged between 180 and 545
g
kg
−1. For each type of feedstock, the highest values of either chemically or thermally degradable C corresponded to the biochar produced at low temperature. Results indicate that low cost methodologies, such as dichromate oxidation and TG, reflected the degree of biochar carbonisation, and could therefore be used to estimate the labile fraction of C in biochar.
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•Occurrence of priority substances and contaminants of emerging concern is reviewed.•Analytical methodologies, monitoring and sampling techniques are discussed.•Four seasons, wet/dry, ...temporal or spatial monitoring of surface water are reviewed.•Surface water chemical status needed for risk assessment, prevention and mitigation.•The monitoring data reviewed may be useful for future regulations.
The contamination of fresh water is a global concern. The huge impact of natural and anthropogenic organic substances that are constantly released into the environment, demands a better knowledge of the chemical status of Earth’s surface water. Water quality monitoring studies have been performed targeting different substances and/or classes of substances, in different regions of the world, using different types of sampling strategies and campaigns. This review article aims to gather the available dispersed information regarding the occurrence of priority substances (PSs) and contaminants of emerging concern (CECs) that must be monitored in Europe in surface water, according to the European Union Directive 2013/39/EU and the Watch List of Decision 2015/495/EU, respectively. Other specific organic pollutants not considered in these EU documents as substances of high concern, but with reported elevated frequency of detection at high concentrations, are also discussed. The search comprised worldwide publications from 2012, considering at least one of the following criteria: 4 sampling campaigns per year, wet and dry seasons, temporal and/or spatial monitoring of surface (river, estuarine, lake and/or coastal waters) and ground waters. The highest concentrations were found for: (i) the PSs atrazine, alachlor, trifluralin, heptachlor, hexachlorocyclohexane, polycyclic aromatic hydrocarbons and di(2-ethylhexyl)phthalate; (ii) the CECs azithromycin, clarithromycin, erythromycin, diclofenac, 17α-ethinylestradiol, imidacloprid and 2-ethylhexyl 4-methoxycinnamate; and (iii) other unregulated organic compounds (caffeine, naproxen, metolachlor, estriol, dimethoate, terbuthylazine, acetaminophen, ibuprofen, trimethoprim, ciprofloxacin, ketoprofen, atenolol, Bisphenol A, metoprolol, carbofuran, malathion, sulfamethoxazole, carbamazepine and ofloxacin).
Most frequent substances as well as those found at highest concentrations in different seasons and regions, together with available risk assessment data, may be useful to identify possible future PS candidates.
Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute ...significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte. Contrary to previous conflicting reports on the ability of halide anions to act as efficient exfoliating electrolytes in electrochemical graphene exfoliation, we show that proper choice of both graphite electrode (e.g., graphite foil) and sodium halide concentration readily leads to the generation of large quantities of single-/few-layer graphene nanosheets possessing a degree of oxidation (O/C ratio down to ∼0.06) lower than that typical of anodically exfoliated graphenes obtained with commonly used electrolytes. The halide anions are thought to play a role in mitigating the oxidation of the graphene lattice during exfoliation, which is also discussed and rationalized. The as-exfoliated graphene materials exhibited a three-dimensional morphology that was suitable for their practical use without the need to resort to any kind of postproduction processing. When tested as dye adsorbents, they outperformed many previously reported graphene-based materials (e.g., they adsorbed ∼920 mg g–1 for methyl orange) and were useful sorbents for oils and nonpolar organic solvents. Supercapacitor cells assembled directly from the as-exfoliated products delivered energy and power density values (up to 15.3 Wh kg–1 and 3220 W kg–1, respectively) competitive with those of many other graphene-based devices but with the additional advantage of extreme simplicity of preparation.
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