Aeroservoelastic design definition of a 20 MW common research wind turbine model

Wind turbine upscaling is motivated by the fact that larger machines can achieve lower levelized cost of energy. However, there are several fundamental issues with the design of such turbines, and there is little public data available for large wind turbine studies. To address this need, we develop a 20 MW common research wind turbine design that is available to the public. Multidisciplinary design optimization is used to define the aeroservoelastic design of the rotor and tower subject to the following constraints: blade‐tower clearance, structural stresses, modal frequencies, tip‐speed and fatigue damage at several sections of the tower and blade. For the blade, the design variables include blade length, twist and chord distribution, structural thicknesses distribution and rotor speed at the rated. The tower design variables are the height, and the diameter distribution in the vertical direction. For the other components, mass models are employed to capture their dynamic interactions. The associated cost of these components is obtained by using cost models. The design objective is to minimize the levelized cost of energy. The results of this research show the feasibility of a 20 MW wind turbine and provide a model with the corresponding data for wind energy researchers to use in the investigation of different aspects of wind turbine design and upscaling. Copyright © 2016 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134256/1/we1970.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134256/2/we1970_am.pd

Unification of trap-limited electron transport in semiconducting polymers

Electron transport in semiconducting polymers is usually inferior to hole transport, which is ascribed to charge trapping on isolated defect sites situated within the energy bandgap. However, a general understanding of the origin of these omnipresent charge traps, as well as their energetic position, distribution and concentration, is lacking. Here we investigate electron transport in a wide range of semiconducting polymers by current-voltage measurements of single-carrier devices. We observe for this materials class that electron transport is limited by traps that exhibit a Gaussian energy distribution in the bandgap. Remarkably, the electron-trap distribution is identical for all polymers considered: the number of traps amounts to 3 × 1023 traps per m3 centred at an energy of ∼3.6 eV below the vacuum level, with a typical distribution width of ∼0.1 eV. This indicates that the electron traps have a common origin that, we suggest, is most likely related to hydrated oxygen complexes. A consequence of this finding is that the trap-limited electron current can be predicted for any polymer. © 2012 Macmillan Publishers Limited. All rights reserved

The effect of enteral bolus feeding on regional intestinal oxygen saturation in preterm infants is age-dependent:a longitudinal observational study

Background The factors that determine the effect of enteral feeding on intestinal perfusion after preterm birth remain largely unknown. We aimed to determine the effect of enteral feeding on intestinal oxygen saturation (r(int)SO(2)) in preterm infants and evaluated whether this effect depended on postnatal age (PNA), postmenstrual age (PMA), and/or feeding volumes. We also evaluated whether changes in postprandial r(int)SO(2) affected cerebral oxygen saturation (r(c)SO(2)). Methods In a longitudinal observational pilot study using near-infrared spectroscopy we measured r(int)SO(2) and r(c)SO(2) continuously for two hours on postnatal Days 2 to 5, 8, 15, 22, 29, and 36. We compared preprandial with postprandial values over time using multi-level analyses. To assess the effect of PNA, PMA, and feeding volumes, we performed Wilcoxon signed-rank tests or logistic regression analyses. To evaluate the effect on r(c)SO(2), we also used logistic regression analyses. Results We included 29 infants: median (range) gestational age 28.1 weeks (25.1-30.7) and birth weight 1025 g (580-1495). On Day 5, r(int)SO(2) values decreased postprandially: mean (SE) 44% (10) versus 35% (7), P = .01. On Day 29, r(int)SO(2) values increased: 44% (11) versus 54% (7), P = .01. Infants with a PMA >= 32 weeks showed a r(int)SO(2) increase after feeding (37% versus 51%, P = .04) whereas infants with a PMA = 32 weeks when greater volumes of enteral feeding are tolerated. We speculate that at young gestational and postmenstrual ages preterm infants are still unable to increase intestinal oxygen saturation after feeding, which might be essential to meet metabolic demands. Trial registration: For this prospective longitudinal pilot study we derived patients from a larger observational cohort study: CALIFORNIA-Trial, Dutch Trial Registry NTR4153

Mixed integer programming in production planning with backlogging and setup carryover : modeling and algorithms

This paper proposes a mixed integer programming formulation for modeling the capacitated multi-level lot sizing problem with both backlogging and setup carryover. Based on the model formulation, a progressive time-oriented decomposition heuristic framework is then proposed, where improvement and construction heuristics are effectively combined, therefore efficiently avoiding the weaknesses associated with the one-time decisions made by other classical time-oriented decomposition algorithms. Computational results show that the proposed optimization framework provides competitive solutions within a reasonable time

CATT voor de boomkwekerij - pilotproeven met sierheesterstek en vaste planten laten kansen voor de toekomst zien

In dit project hebben we het perspectief voor CATT-behandelingen (Controlled Atmosphere Temperature Treatment) voor boomkwekerijgewassen onderzocht. Deze methode combineert een CA-behandeling (gewijzigde luchtsamenstelling door aanpassing van CO2-en O2-condities) met een temperatuurbehandeling. Hiervoor wordt het plantmateriaal gedurende een bepaalde periode in een gasdichte cel bewaard. CATT-behandelingen zijn een duurzame vorm van plaagbestrijding omdat er geen chemische middelen aan te pas komen en omdat er geringe kans is op resistentieontwikkeling van de plaagorganismen. Bovendien kan deze methode zeer snel in praktijk worden geïmplementeerd omdat deze geen wettelijke toelating behoeft. Zo zijn in korte tijd CATT-behandelingen ontwikkeld voor het bestrijden van plagen in aardbei, die nu succesvol in praktijk worden toegepast. In dit project hebben we twee sierheesters in de stekfase (Buxus sempervirens en Ilex altaclerensis) en vier soorten vaste planten in de winterbewaring (Astilbe japonica, Geranium sanguineum, Phlox paniculata, Paeonia officinalis) behandeld en vergeleken met onbehandelde controles

Inherited susceptibility to bleomycin-induced chromatid breaks in cultured peripheral blood lymphocytes

Background: Susceptibility to bleomycin-induced chromatid breaks in cultured peripheral blood lymphocytes may reflect the way a person deals with carcinogenic challenges. This susceptibility (also referred to as mutagen sensitivity) has been found to be increased in patients with environmentally related cancers, including cancers of the head and neck, lung, and colon, and, in combination with carcinogenic exposure, this susceptibility can greatly influence cancer risk. The purpose of this study was to assess the heritability of mutagen sensitivity. Methods: Heritability was determined by use of a maximum likelihood method that employed the FISHER package of pedigree analysis. Bleomycin-induced breaks per cell values for 135 healthy volunteers without cancer were determined. These individuals were from 53 different pedigrees and included 25 monozygotic twin pairs (n = 50), 14 pairs of dizygotes (twin pairs and siblings, n = 28), and 14 families selected on the basis of a first-degree relative who was successfully treated for head and neck cancer and who had no sign of recurrence for at least 1 year. All data were analyzed simultaneously, and different models of familial resemblance were fitted to the data. All P values are two-sided. Results: Our results showed no evidence for the influence of a shared family environment on bleomycin-induced chromatid breaks. Genetic influences, however, were statistically significant (P = .036) and accounted for 75% of the total variance. Conclusions: The high heritability estimate of the susceptibility to bleomycin-induced chromatid breaks indicates a clear genetic basis. The findings of this study support the notion that a common genetic susceptibility to DNA damage - and thereby a susceptibility to cancer - may exist in the general population