338 research outputs found
The Impact of Wind Power Support Schemes on Technology Choices
Germany changed renewable remuneration for wind power from a fixed Feed-In Tariff (FIT) to a floating Market Premium Scheme (MPS) in 2012. One aim of this adjustment was to better align the supply of generated wind electricity with the demand for it, e.g. through more system-friendly wind turbine technology choices. In energy systems with a high share of variable renewable energies, such turbines produce a higher share of their production at lower wind speeds and thus can reduce the need for alternative flexibility options like back-up capacity, storage, grid extensions and demand side measures. However, based on a wind power investment model, I show that the MPS fails to convey strong enough incentives to project developers to significantly alter their investment decisions as long as these base their investments on current electricity market price profiles and are limited by their access to risk-averse project finance. One reform proposal to support the installation of system-friendly turbines is a change in the production volume-based benchmark approach which plays an integral part in both the fixed FIT and the MPS. The investment model indicates that such a revised policy can incentivize the deployment of moderately more system-friendly wind power technologies at some locations. An alternative option is to shift to a production value-based benchmark approach. It directly reflects the future additional market value of system-friendly turbines in today's remuneration structure. Thus, this approach sets incentives also for investors without perfect foresight - or with financing constraints - to deploy more systemfriendly turbines that meet the requirements of power systems with increasing shares of wind power
Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation
OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (
Fluorescence Single Particle Tracking for the Characterization of Submicron Protein Aggregates in Biological Fluids and Complex Formulations
To evaluate the potential of fluorescence single particle tracking (fSPT) for the characterization of submicron protein aggregates in human serum, plasma and formulations containing human serum albumin (HSA).
A monoclonal IgG was covalently labeled with a fluorescent dye and cross-linked with glutaraldehyde. IgG aggregates and fluorescent beads of 0.1 mu m (control) were diluted in buffer, serum and plasma, and their size distributions were analyzed by fSPT and nanoparticle tracking analysis (NTA). In a separate experiment, IgG and HSA, fluorescently labeled with different dyes, were mixed and subjected to heat stress. The stressed sample was analyzed by fSPT using a dual color mode and by NTA.
The accuracy and precision of fSPT proved to be comparable to NTA. fSPT was able to successfully measure all the samples in buffer, serum and plasma. The average size of the cross-linked protein aggregates showed a slight increase in biological fluids. Moreover, fSPT analysis showed that a significant proportion of the aggregates formed by subjecting an IgG/HSA mixture to heat stress were composed of both proteins.
fSPT is a powerful technique for the characterization of submicron protein aggregates in biological fluids and complex formulations
Wind Providing Balancing Reserves: An Application to the German Electricity System of 2025
This paper analyzes the influence of wind turbines as new participants on prices and allocation within balancing markets. We introduce the cost-minimizing electricity sector model ELMOD-MIP, that includes detailed unit-commitment constraints, complex combined heat and power constraints, and minimum bid sizes for balancing capacity reservation. The model also features a novel approach of modeling balancing reservation by considering possible activation costs already during the reservation phase, mimicking the activation anticipation of market participants. The model includes the spot and balancing market of Germany and is applied to scenarios for 2013 and 2025. The results for 2025 show, in comparison to 2013, a price increase for positive and negative reserves, in case no new participants enter the market. With the participation of wind turbines the cost for balancing provision is reduced by 40%, but above 2013 values. The relative cost savings from wind participation are higher for negative reserve provision than positive reserve provision, as wind turbines can use their full capacity if not activated and do not have to be curtailed ex ante. The participation of wind turbines especially reduces the occurrence of peak prices for positive and negative reserves in 2025. This reduction effect occurs even with a relatively low share where wind turbines participate with only five percent of their capacity. Therefore, further fostering the process of allowing wind turbines to participate in the German reserve market seems favorable
Sensitive Spectroscopic Detection of Large and Denatured Protein Aggregates in Solution by Use of the Fluorescent Dye Nile Red
The fluorescent dye Nile red was used as a probe for the sensitive detection of large, denatured aggregates of the model protein β-galactosidase (E. coli) in solution. Aggregates were formed by irreversible heat denaturation of β-galactosidase below and above the protein’s unfolding temperature of 57.4°C, and the presence of aggregates in heated solutions was confirmed by static light scattering. Interaction of Nile red with β-galactosidase aggregates led to a shift of the emission maximum (λmax) from 660 to 611 nm, and to an increase of fluorescence intensity. Time-resolved fluorescence and fluorescence correlation spectroscopy (FCS) measurements showed that Nile red detected large aggregates with hydrodynamic radii around 130 nm. By steady-state fluorescence measurements, it was possible to detect 1 nM of denatured and aggregated β-galactosidase in solution. The comparison with size exclusion chromatography (SEC) showed that native β-galactosidase and small aggregates thereof had no substantial effect on the fluorescence of Nile red. Large aggregates were not detected by SEC, because they were excluded from the column. The results with β-galactosidase demonstrate the potential of Nile red for developing complementary analytical methods that overcome the size limitations of SEC, and can detect the formation of large protein aggregates at early stages
Sowing the Wind and Reaping the Whirlwind? The Effect of Wind Turbines on Residential Well-Being
This paper investigates the effect of wind turbines on residential well-being in Germany, using panel data from the German Socio-Economic Panel (SOEP) and a unique, novel data set on wind turbines for the time period between 2000 and 2012. Using a Geographical Information System (GIS), it calculates the distance from households to the nearest wind turbines to determine whether an individual is affected by disamenities, e.g. through visual pollution. The depth of our unique, novel data set on wind turbines, which has been collected at the regional level and which includes, besides their exact geographical coordinates, their construction dates, allows estimating the causal effect of wind turbines on residential well-being, using difference-in-difference propensity-score and spatial matching techniques. We demonstrate that the construction of a new wind turbine in a treatment area of 4000 metres around households has a significantly negative impact on life satisfaction. Moreover, this effect is found to be of transitory nature. Contrasting the implicit monetary valuation with the damage through CO2 emissions avoided by wind turbines, wind power turns out to be a favorable technology despite robust evidence for negative externalities
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