Agassiz’s desert tortoise (Gopherus agassizii) activity areas are little changed after wind turbine induced fires in California

Wind turbine-induced fires at a wind energy facility in California, USA, provided an opportunity to study the before and after effects of fire on a population of protected Agassiz’s desert tortoises (Gopherus agassizii) in the Sonoran Desert, a species and ecosystem poorly adapted to fire. We compared annual activity areas (AAs) of tortoises in 2011 and 2013, before and after two 2012 fires, with those of tortoises in adjacent areas unaffected by the same fires. Tortoises in both AAs affected by fire or unaffected by fire occupied the same general AAs in 2013, after the fires, as they did in 2011, before the fires. Some tortoises had both their 2011 and 2013 AAs completely or almost completely within the areas burned by the 2012 fires, despite the proximity of unburned habitat. None of the tortoises with 2011 AAs subsequently unaffected by the 2012 fires shifted their AAs into burned habitat in 2013. For the fire-affected group of tortoises, the mean percentages of 2011 and 2013 AAs burned by the 2012 fires were not significantly different, showing fidelity to the burned areas. Tortoises in both groups generally occupied consistent AAs, even post fire, placing them at potential risk of exposure to unfavourable burned habitat.

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A Study of the Impact of Pitch Misalignment on Wind Turbine Performance

Machines ◽

10.3390/machines7010008 ◽

2019 ◽

Vol 7 (1) ◽

pp. 8 ◽

Cited By ~ 6

Author(s):

Davide Astolfi

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Power Output ◽

Wind Farm ◽

Reactive Power ◽

Power Production ◽

Test Case ◽

Before And After ◽

Input Variables ◽

The Impact

Pitch angle control is the most common means of adjusting the torque of wind turbines. The verification of its correct function and the optimization of its control are therefore very important for improving the efficiency of wind kinetic energy conversion. On these grounds, this work is devoted to studying the impact of pitch misalignment on wind turbine power production. A test case wind farm sited onshore, featuring five multi-megawatt wind turbines, was studied. On one wind turbine on the farm, a maximum pitch imbalance between the blades of 4.5 ° was detected; therefore, there was an intervention for recalibration. Operational data were available for assessing production improvement after the intervention. Due to the non-stationary conditions to which wind turbines are subjected, this is generally a non-trivial problem. In this work, a general method was formulated for studying this kind of problem: it is based on the study, before and after the upgrade, of the residuals between the measured power output and a reliable model of the power output itself. A careful formulation of the model is therefore crucial: in this work, an automatic feature selection algorithm based on stepwise multivariate regression was adopted, and it allows identification of the most meaningful input variables for a multivariate linear model whose target is the power of the wind turbine whose pitch has been recalibrated. This method can be useful, in general, for the study of wind turbine power upgrades, which have been recently spreading in the wind energy industry, and for the monitoring of wind turbine performances. For the test case of interest, the power of the recalibrated wind turbine is modeled as a linear function of the active and reactive power of the nearby wind turbines, and it is estimated that, after the intervention, the pitch recalibration provided a 5.5% improvement in the power production below rated power. Wind turbine practitioners, in general, should pay considerable attention to the pitch imbalance, because it increases loads and affects the residue lifetime; in particular, the results of this study indicate that severe pitch misalignment can heavily impact power production.

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Remote Sensing of Forest Fire Severity and Vegetation Recovery

International Journal of Wildland Fire ◽

10.1071/wf9960125 ◽

1996 ◽

Vol 6 (3) ◽

pp. 125 ◽

Cited By ~ 203

Author(s):

JD White ◽

KC Ryan ◽

CC Key ◽

SW Running

Keyword(s):

Satellite Data ◽

Fire Severity ◽

Canopy Cover ◽

Burn Severity ◽

Vegetation Recovery ◽

Electromagnetic Spectrum ◽

Vegetation Types ◽

Burned Areas ◽

Before And After ◽

Forested Areas

Burned forested areas have patterns of varying burn severity as a consequence of various topographic, vegetation, and meteorological factors. These patterns are detected and mapped using satellite data. Other ecological information can be abstracted from satellite data regarding rates of recovery of vegetation foliage and variation of burn severity on different vegetation types. Middle infrared wavelengths are useful for burn severity mapping because the land cover changes associated with burning increase reflectance in this part of the electromagnetic spectrum. Simple stratification of Landsat Thematic Mapper data define varying classes of burn severity because of changes in canopy cover, biomass removal, and soil chemical composition. Reasonable maps of burn severity are produced when the class limits of burn severity reflectance are applied to the entire satellite data. Changes in satellite reflectance over multiple years reveal the dynamics of vegetation and fire severity as low burn areas have lower changes in reflectance relative to high burn areas. This results as a consequence of how much the site was altered due to the burn and how much space is available for vegetation recovery. Analysis of change in reflectance across steppe, riparian, and forested vegetation types indicate that fires potentially increase biomass in steppe areas, while riparian and forested areas are slower to regrow to pre-fire conditions. This satellite-based technology is useful for mapping severely burned areas by exploring the ecological manifestations before and after fire.

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Micro-geographic variation in burrow use of Agassiz’s desert tortoises in the Sonoran Desert of California

Herpetological Journal ◽

10.33256/hj30.4.177188 ◽

2020 ◽

pp. 177-188

Author(s):

Kristy Cummings

Keyword(s):

Geographic Variation ◽

Sonoran Desert ◽

Radio Telemetry ◽

Gopherus Agassizii ◽

General Aspect ◽

Annual Cycles ◽

Local Geology ◽

Burrow Use

Little has been published regarding the burrowing habits of Agassiz’s desert tortoises (Gopherus agassizii) in the Sonoran Desert of California. We monitored the interactions of tortoises with their burrows, and other tortoises, via radio-telemetry at two nearby sites between the Cottonwood and Orocopia Mountains, from 2015-2018. We examined how annual cycles of drought and non-drought years, behaviourally affected how tortoises use their burrows (i.e., burrow fidelity, cohabitation, and location), including the timing of the tortoise brumation period. Burrow locations were strongly dependent on local geology and topography, with a tendency to orientate in conformance with the general aspect of the landscape. The timing of brumation was similar to records for G. agassizii throughout their range (with a few exceptions). There was no difference in the estimated number of burrows used per 30 days between the active seasons (2017 and 2018) at the Orocopia site, despite the occurrence of drought in 2018.

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Fabrication and Experimentation of Diffuser Augmented Wind Turbine

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b3792.078219 ◽

2019 ◽

Vol 8 (2) ◽

pp. 6047-6052

Keyword(s):

Wind Tunnel ◽

Wind Energy ◽

Wind Turbine ◽

Ansys Fluent ◽

Throat Region ◽

Pressure Transducers ◽

Reference Velocity ◽

Energy Facility ◽

Horizontal Axis Wind Turbines ◽

Flow Through

Wind Energy is turning into a big supply of renewable energy throughout the globe. This ever increasing field can probably reach the limit of accessibility and utility with the wind energy facility sites and size of the turbine itself. Therefore, it's needed to develop wind capturing devices that may produce energy within the locations wherever typical horizontal axis wind turbines (HAWTs) are too unrealistic to put in and operate. A diffuser augmented wind turbine (DAWT) is one such invention. DAWTs increase the ability output of the rotor by increasing the wind speed into the rotor employing a duct. The main objective of the project is to analyze the flow through the diffuser by placing it in wind tunnel and further the results are compared with the computational results. The purpose of investigating the flow through, the diffuser is to find out the behavior of wind flow at the throat region of the diffuser. Numerical analysis of diffuser is performed using the tool ANSYS FLUENT 15 and then by experimentation in wind tunnel. Experiments were carried out for investigating the flow pattern inside the circular profile diffuser of radius 60mm, Throat diameter of 200mm, inlet and outlet diameter of diffuser is 320mm. Pitot tubes are inserted on the rake and then mount on the throat region of diffuser for flow measurement in that region. Differential pressure transducers which gives voltage output are used for sensing the pressures from Pitot tubes, static tubes which is mount on surface of test section of tunnel and PS tube which is used for reference velocity. Further obtained pressure will be converted to velocity and get the required result. After completion of computational and experimental work comparable results were obtained.

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Changes in TMS measures induced by repetitive TMS

10.1093/oxfordhb/9780198832256.013.19 ◽

2021 ◽

Author(s):

Joseph Classen ◽

Ying-Zu Huang ◽

Christoph Zrenner

Keyword(s):

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Repetitive Transcranial Magnetic Stimulation ◽

Low Frequency ◽

Corticospinal Excitability ◽

After Effects ◽

Before And After ◽

Neurophysiological Mechanisms ◽

Synaptic Changes ◽

Theta Burst

Commonly used repetitive transcranial magnetic stimulation (rTMS) protocols, including regular rTMS, intermittent and continuous theta-burst stimulation (TBS) and quadripulse stimulation (QPS) are presented with respect to their induced neuromodulatory after-effects and the underlying cellular and synaptic neurophysiological mechanisms. The anatomical target is typically primary motor cortex since motor evoked potentials (MEPs) before and after the intervention can be used to assess effects of the respective rTMS protocol. High-frequency regular rTMS and intermittent TBS protocols tend to increase corticospinal excitability as indexed by MEP amplitude, whereas low-frequency regular rTMS and continuous TBS protocols tend to reduce corticospinal excitability. These effects are primarily due to LTP-like and LTD-like synaptic changes mediated by GABA and NMDA receptors. Changes in the balance between excitatory and inhibitory cortical microcircuits play a secondary role, with inconsistent effects as determined by paired-pulse TMS protocols. Finally, the challenge of large inter-subject response variability, and current directions of research to optimize rTMS effects through EEG-dependent personalized TMS are discussed.

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Phase resetting of the respiratory cycle before and after unilateral pontine lesion in cat

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.2.721 ◽

1992 ◽

Vol 72 (2) ◽

pp. 721-730 ◽

Cited By ~ 33

Author(s):

Y. Oku ◽

T. E. Dick

Keyword(s):

Superior Laryngeal Nerve ◽

Pattern Generator ◽

Respiratory Cycle ◽

Phase Resetting ◽

After Effects ◽

Inspiratory Phase ◽

Subsequent Cycle ◽

Before And After ◽

Pontine Lesion ◽

The Stability

The pontine respiratory group (PRG) facilitates the mechanism for terminating the inspiratory phase but may influence other phases in the respiratory cycle as well. We determined the effects of PRG lesions on the response of the respiratory cycle to superior laryngeal nerve stimulation delivered in each phase of the cycle in decerebrate, vagotomized, paralyzed, and ventilated cats (n = 6). We measured the duration of inspiration (TI) and expiration (TE) for three breaths before and in the perturbed breath and TI for three breaths after the perturbation. The delay to next inspiration was plotted against the phase at which the stimulus was delivered. Before lesioning, premature inspiratory termination was followed by phase-dependent shortening of TE. After lesioning, premature inspiratory termination did not systematically change the following TE. Breath-by-breath variability (measured 50 breaths) increased and stimulus after-effects (prolonged TI in the subsequent cycle) were augmented following lesions. These data indicate that the PRG plays an important role in the control of TE after perturbation and in the stability of the respiratory central pattern generator.

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Hibernaculum Use by a Population of Desert Tortoises (Gopherus agassizii) in the Sonoran Desert

Journal of Herpetology ◽

10.2307/1564985 ◽

1995 ◽

Vol 29 (3) ◽

pp. 361 ◽

Cited By ~ 19

Author(s):

Scott J. Bailey ◽

Cecil R. Schwalbe ◽

Charles H. Lowe

Keyword(s):

Sonoran Desert ◽

Gopherus Agassizii

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IDENTIFICATION OF BURNED AREAS BY SPECIAL INDEX IN A CERRADO REGION OF THE STATE OF TOCANTINS, BRAZIL

FLORESTA ◽

10.5380/rf.v48i4.57362 ◽

2018 ◽

Vol 48 (4) ◽

pp. 553

Author(s):

Ingridy Mikaelly Pereira Sousa ◽

Edmar Vinicius de Carvalho ◽

Antonio Carlos Batista ◽

Igor Eloi Silva Machado ◽

Maira Elisa Ferreira Tavares ◽

...

Keyword(s):

Near Infrared ◽

Short Wave ◽

Burned Area ◽

Landsat 8 ◽

Visual Interpretation ◽

Burned Areas ◽

Area Of Interest ◽

Before And After ◽

Kappa Value ◽

The Difference

Obtaining information on burned areas has been studied and improved in the last decades, and the biggest question is the acquisition of consistent and detailed information about the occurrence of burnings in a simple and effective way. In view of this, remote sensing is a very interesting tool because it allows obtaining information in large areas of difficult access. The identification of areas burned by orbital data is directly related to their spectral behavior. The objective of this study was to analyze the performance of spectral indices in the identification of burned area in OLI/Landsat-8 satellite images. The indices for the before and after fire images were calculated using bands of red and near infrared: NDVI, MSAVI, SAVI, and GEMI, and bands of near infrared and short wave infrared: NBR, BAIMmod, and MIRBImod. The difference between pre and post-fire index was also calculated: dNDVI, dMSAVI, dSAVI, dGEMI, dNBR, dBAIMmod, and dMIRBImod. From these indices, six different compositions (RGB) were created and later they were segmented and classified in a non-supervised way and soon after made the extraction of the area of interest. The results of this classification were validated with the reference data obtained through the visual interpretation of the image. The methods had shown a good quality of classification, with a percentage of accuracy ranging from 85.54 to 92.46% and Kappa value of 0.70 to 0.89. The best method was the dNBR, NBRpost-fire, and dMIRBImod indices in the RGB composite.

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