Statistical analysis of the challenges to high penetration of wind energy

2014 Summer.Includes bibliographical references.Grid penetration of renewable energy technologies, especially wind power, is higher than ever and continues to increase. The inherent stochastic variability of wind makes predicting wind, and thus power generation difficult. Generating companies usually don't openly share power output predictions or historical generation data which increases the level of complexity when determining new wind plant locations or estimating delivered grid level power. This work focuses on statistical data analysis and advanced data modeling related to wind power forecasting and generation. The first part of this thesis uses power output logs from several wind plants and a well-known forecasting method to determine energy storage requirements for individual wind plant contract firming. Forecasts of varying accuracy are used to characterize storage requirements based on contract period length, forecast lead time, and forecast accuracy. Results show that forecast error distributions are effected more by forecast accuracy and lead time than wind plant size and location. The biggest reductions in produced power deviations can be achieved by increasing forecast accuracy and decreasing forecast lead time. The second part of this work develops a statistical analysis which allows estimation of contract firming requirements for a specific wind plant location without the need for time series wind and forecast data. The developed method requires only a wind speed and forecasting error distribution. Using these distributions, deviations between forecast to produced power and energy can be estimated. Results from comparing to historical time series data show this method is accurate to within 10% of actual amounts. Since distributions are much more easily attained than historical time series data, this analysis is useful for developers when evaluating potential new locations. The third part of this work uses a pattern matching algorithm to recognize wind ramp events and separate the forecasting error due to timing from the forecasting error due to magnitude. Wind ramp detection is achieved by developing a pattern matching algorithm which is also shown to work in identifying start and stop transients in electrical device current draw. The analysis confirms wind ramp events can be detected by calculating a bimodal ranking value from a histogram of power data, and the effects of forecast timing and magnitude can be separated from overall forecasting errors. The results of this analysis show magnitude errors contribute more in large wind ramp events, while timing errors contribute more in small ramp events

Smc5/6 is required for repair at collapsed replication forks.

In eukaryotes, three pairs of structural-maintenance-of-chromosome (SMC) proteins are found in conserved multisubunit protein complexes required for chromosomal organization. Cohesin, the Smc1/3 complex, mediates sister chromatid cohesion while two condensin complexes containing Smc2/4 facilitate chromosome condensation. Smc5/6 scaffolds an essential complex required for homologous recombination repair. We have examined the response of smc6 mutants to the inhibition of DNA replication. We define homologous recombination-dependent and -independent functions for Smc6 during replication inhibition and provide evidence for a Rad60-independent function within S phase, in addition to a Rad60-dependent function following S phase. Both genetic and physical data show that when forks collapse (i.e., are not stabilized by the Cds1Chk2 checkpoint), Smc6 is required for the effective repair of resulting lesions but not for the recruitment of recombination proteins. We further demonstrate that when the Rad60-dependent, post-S-phase Smc6 function is compromised, the resulting recombination-dependent DNA intermediates that accumulate following release from replication arrest are not recognized by the G2/M checkpoint

Smc5/6 maintains stalled replication forks in a recombination-competent conformation

The Smc5/6 structural maintenance of chromosomes complex is required for efficient homologous recombination (HR). Defects in Smc5/6 result in chromosome missegregation and fragmentation. By characterising two Schizosaccharomyces pombe smc6 mutants, we define two separate functions for Smc5/6 in HR. The first represents the previously described defect in processing recombination-dependent DNA intermediates when replication forks collapse, which leads to increased rDNA recombination. The second novel function defines Smc5/6 as a positive regulator of recombination in the rDNA and correlates mechanistically with a requirement to load RPA and Rad52 onto chromatin genome-wide when replication forks are stably stalled by nucleotide depletion. Rad52 is required for all HR repair, but Rad52 loading in response to replication fork stalling is unexpected and does not correlate with damage-induced foci. We propose that Smc5/6 is required to maintain stalled forks in a stable recombination-competent conformation primed for replication restart

Assessment of Aeroacoustic Simulations of the High-Lift Common Research Model

This paper presents further validation of PowerFLOWR aeroacoustic simulations of the High-Lift Common Research Model through comparisons with experimental data from a recently completed wind tunnel test. Preliminary time- averaged surface pressure and microphone array data from the experiment are in reasonably good agreement with the simulations, and the slat is shown to be a dominant noise source on this model. The simulations did not predict slat tones that were very prominent in the experiment, but they did capture the broadband component of slat noise in the low-frequency range up to 1 kHz at full scale. Future tests are planned to demonstrate slat noise reduction technology, and simulations are being used to guide this development

Regulation of Chk1

Chk1 is a serine/threonine protein kinase that is the effector of the G2 DNA damage checkpoint. Chk1 homologs have a highly conserved N-terminal kinase domain, and a less conserved C-terminal regulatory domain of ~200 residues. In response to a variety of genomic lesions, a number of proteins collaborate to activate Chk1, which in turn ensures that the mitotic cyclin-dependent kinase Cdc2 remains in an inactive state until DNA repair is completed. Chk1 activation requires the phosphorylation of residues in the C-terminal domain, and this is catalyzed by the ATR protein kinase. How phosphorylation of the C-terminal regulatory domain activates the N-terminal kinase domain has not been elucidated, though some studies have suggested that this phosphorylation relieves an inhibitory intramolecular interaction between the N- and C-termini. However, recent studies in the fission yeast Schizosaccharomyces pombe have revealed that there is more to Chk1 regulation than this auto-inhibition model, and we review these findings and their implication to the biology of this genome integrity determinant

Comparative Study of Active Flow Control Strategies for Lift Enhancement of a Simplified High-Lift Configuration

Numerical simulations have been performed for a simplified high-lift (SHL) version of the Common Research Model (CRM) configuration, where the Fowler flaps of the conventional high-lift (CRM-HL) configuration are replaced by a set of simple hinged flaps. These hinged flaps are equipped with integrated modular active flow control (AFC) cartridges on the suction surface, and the resulting geometry is known as the CRM-SHL-AFC configuration. The main objective is to make use of AFC devices on the CRM-SHL-AFC configuration to recover the aerodynamic performance (lift) of the CRM-HL configuration. In the current paper, a Lattice Boltzmann method-based computational fluid dynamics (CFD) code, known as PowerFLOWQ is used to simulate the entire flow field associated with the CRM-SHL-AFC configuration equipped with several different types of AFC devices. The transonic version of the PowerFLOWQ code that has been validated for high speed flows is used to accurately simulate the flow field generated by the high-momentum actuators required to mitigate reversed flow regions on the suction surfaces of the main wing and the flap. The numerical solutions predict the expected trends in aerodynamic forces as the actuation levels are increased. More efficient AFC systems and actuator arrangements emerged based on the parametric studies performed prior to a Fall 2018 wind tunnel test. Preliminary comparisons of the numerical solutions for lift and surface pressures are presented here with the experimental data, demonstrating the usefulness of CFD for predicting the flow field and lift characteristics of AFC-enabled high-lift configurations

The PHASES Differential Astrometry Data Archive. I. Measurements and Description

The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) monitored 51 sub-arcsecond binary systems to determine precision binary orbits, study the geometries of triple and quadruple star systems, and discover previously unknown faint astrometric companions as small as giant planets. PHASES measurements made with the Palomar Testbed Interferometer (PTI) from 2002 until PTI ceased normal operations in late 2008 are presented. Infrared differential photometry of several PHASES targets were measured with Keck Adaptive Optics and are presented.Comment: 33 pages emulateapj, Accepted to A

A bioclimatic approach to integrated design : form, technology, and architectural knowledge

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1996.Includes bibliographical references (p. 173-175).This thesis explores a holistic design process through which architectural elements can engage the dynamic forces of natural phenomena and integrate the spatial and temporal experience of building form with its physical environment. The framework for this exploration is a contextual mapping of dynamical systems and complexity theory to the processes of architectural design. By incorporating concepts and methods from the study of non-linear dynamics, a broad base of scientific knowledge aimed at understanding physical behavior in nature, this thesis proposes a synthetic relationship between architectural elements, their physical performance in the context of natural phenomena, and their contribution to a coherent spatial structure. Modern technological imperatives have rephrased the sensible relationships between architecture, climate, and inhabited space as a problem for "environmental controls". The contemporary urban office building, under economic pretenses, exhibits a particular over-dependence on external machinery for light, ventilation, and thermal comfort, often to the detriment of physical experience. This thesis emphasizes the use of scientific knowledge and computational tools in the early processes of design in an attempt to investigate the manifestations of physical energy -- light, air, and heat --in the building's final form. By addressing these physical performance criteria as spatial influences during preliminary design, this thesis supports an integrated framework for professional collaboration and examines a cultural context for the application of architectural knowledge. A bioclimatic approach to design, therefore, is a synthetic response to the dialectic between the tectonics of physical experience and the dynamics of the natural environment.by Matthew J. O'Connell.M.Arch