21 results on '"Christopher Beale"'
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2. A Global Analysis of Land Surface Temperature Diurnal Cycle Using MODIS Observations
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Zahra Sharifnezhadazizi, Hamid Norouzi, Satya Prakash, Christopher Beale, and Reza Khanbilvardi
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- 2019
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3. Degree of Freedom Selection Approaches for MIMO Vibration Test Design
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Christopher Beale, Ryan Schultz, Chandler Smith, and Timothy Walsh
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- 2022
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4. 17.1 A digitally assisted CMOS WiFi 802.11ac/11ax front-end module achieving 12% PA efficiency at 20dBm output power with 160MHz 256-QAM OFDM signal.
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Yuen-Hui Chee, Fatih Golcuk, Toru Matsuura, Christopher Beale, James F. Wang, and Osama Shana'a
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- 2017
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5. Comparison of Diurnal Variation of Land Surface Temperature From GOES-16 ABI and MODIS Instruments
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H. Norouzi, Christopher Beale, Jorge E. González-Cruz, A. R. Bah, Peng Yu, Anna Vaculik, Reginald Blake, Yunyue Yu, and Z. Sharifnezhadazizi
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Land surface temperature ,Diurnal temperature variation ,0211 other engineering and technologies ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,Surface energy balance ,Climatology ,Geostationary orbit ,Polar ,Environmental science ,Satellite ,Moderate-resolution imaging spectroradiometer ,Electrical and Electronic Engineering ,Scale (map) ,021101 geological & geomatics engineering - Abstract
Land surface temperature (LST) and its diurnal variation are the critical factors in many aspects of climate study, surface energy balance, and environmental applications. Several satellite-based LST products are available for retrievals from regional to a global scale. However, due to the differences in sensor configurations and retrieval algorithms, these products may not necessarily be consistent. In this letter, the consistency of spatial and temporal skin temperature variations from two infrared satellite platforms has been evaluated over the contiguous United States (CONUS). Comparisons are made between the LST products from the newly launched Geostationary Operation Environmental Satellite R Series (GOES-R) advanced baseline imager (ABI) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on both Aqua and Terra satellites which are polar orbiting. Overall, both products show a general agreement in their diurnal variations with differences mostly under 2 K. However, a temperature-dependent inconsistency has been detected. The MODIS LST product seems to estimate higher temperatures in the summer months while the GOES product estimates higher temperatures during the winter months. Moreover, the maximum observed diurnal differences could reach up to 10 K in mountainous regions. The results suggest that the corresponding temperature differences should be accounted for when LST diurnal variations are compared or generated from satellite observations.
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- 2020
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6. ‘His winnowing fan is in his hand’
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Christopher Beale and George Georgiou
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Computer science ,Order (business) ,Winnowing ,Reliability (statistics) ,Pathology and Forensic Medicine ,Reliability engineering - Abstract
In order to minimize the risk of wrongful convictions from unreliable expert evidence judges have long considered it necessary to have regard to the reliability of expert evidence when considering ...
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- 2020
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7. Sol-Gel Derived, Inkjet Printed, and Flash Lamp Annealed Ta2o5 on Flexible, Interdigitated Electrodes for Capacitive Ph Sensing at High Ionic Strength
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Christopher Beale, Antonio Altana, Stefanie Hamacher, Alexey Yakushenko, Dirk Mayer, Bernhard Wolfrum, and Andreas Offenhäusser
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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8. Passive acoustic damage detection of structural cavities using flow-induced acoustic excitations
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David J. Willis, Murat Inalpolat, Christopher Beale, and Christopher Niezrecki
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Damage detection ,Materials science ,Mechanical Engineering ,Acoustics ,Flow (psychology) ,Biophysics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Acoustic transmission ,01 natural sciences ,Fuselage ,0103 physical sciences ,Passive detection ,0210 nano-technology ,010301 acoustics - Abstract
Cavities with different geometries represent the internal volumes of various engineering applications such as cabins of passenger cars, fuselages and wings of aircraft, and internal compartments of wind turbine blades. Transmissibility of acoustic excitation to and from these cavities is affected by material and cross-sectional properties of the structural cavity, as well as potential damage incurred. A new structural damage detection methodology that relies on the detectability of the changes in acoustic transmissibility across the boundaries of structural cavities is proposed. The methodology is described with a specific focus on the passive damage detection approach applied to cavity internal acoustic pressure responses under external flow-induced acoustic excitations. The approach is realized through a test plan that considers a wind turbine blade section subject to various damage types, severity levels, and locations, as well as wind speeds tested in a subsonic wind tunnel. A number of statistics-based metrics, including power spectral density estimates, band power differences from a known baseline, and the sum of absolute difference, were used to detect damage. The results obtained from the test campaign indicated that the passive acoustic damage detection approach was able to detect all considered hole-type damages as small as 0.32 cm in diameter and crack-type damages 1.27 cm in length. In general, the ability to distinguish damage from the baseline state improved as the damage increased in severity. Damage type, damage location, and flow speed influenced the ability to detect damage, but were not significant enough to prevent detection. This article serves as an overall proof of concept of the passive-based damage detection approach using flow-induced acoustic excitations on structural cavities of a wind turbine blade. The laboratory-scale results reveal that acoustic-based monitoring has great potential to be used as a new structural health monitoring technique for utility-scale wind turbine blades.
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- 2019
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9. Active acoustic damage detection of structural cavities using internal acoustic excitations
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Christopher Niezrecki, Christopher Beale, and Murat Inalpolat
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Signal processing ,Damage detection ,Materials science ,Mechanical Engineering ,Acoustics ,Biophysics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Transmissibility (vibration) ,0103 physical sciences ,Structural health monitoring ,0210 nano-technology ,010301 acoustics - Abstract
A novel structural damage detection methodology that relies on the detectability of the changes in acoustic transmissibility across boundaries of structural cavities is investigated. The approach focuses on active damage detection by leveraging the acoustic pressure responses measured external to structural cavities while exposed to internal acoustic excitations. The active damage detection concept is first demonstrated on a 4 m wind turbine blade using acoustic beamforming techniques to confirm that the acoustic energy transmitted through a damaged surface increases local to the damage compared to an undamaged surface. The concept is further verified, only considering acoustic pressure responses measured from limited microphones positioned at various distances from a ~46 m wind turbine blade. A comprehensive testing campaign is developed and executed on the utility-scale blade considering various damage types, severity levels, and locations. The data are analyzed using a combination of spectral analysis and statistics-based metrics to detect and track the progression of damage as well as identify trends across the test variables. Overall, large increases in the power spectral density were observed from the pressure responses measured external to the structure in most cases. The spectral differences increased as the damage became more severe and damage as small as 5.1 cm in length was easily detected from multiple sensors up to 17.1 m from the damage location. Damage was easily detected when implemented before the mid-length of the blade using simple signal processing algorithms and preliminary test configurations. The data acquired in this work serve as a preliminary investigation into the capability of the approach on complex structures and paves the path for future research into the signal processing techniques and test configurations that will enhance the performance of the active acoustic damage detection approach.
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- 2019
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10. Sensor Selection for MIMO Vibration: Summary Slides [Slides]
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Christopher Beale and Ryan Schultz
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- 2021
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11. Downscaling of Satellite Land Surface Temperature Data Over Urban Environments
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Anna F. Vaculik, Justine Ginchereau, Makini Valentine, Reginald Blake, A. R. Bah, H. Norouzi, and Christopher Beale
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010504 meteorology & atmospheric sciences ,Land surface temperature ,0211 other engineering and technologies ,Skin temperature ,02 engineering and technology ,01 natural sciences ,Temporal resolution ,Geostationary orbit ,High spatial resolution ,Environmental science ,Satellite ,Image resolution ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Downscaling ,Remote sensing - Abstract
The purpose of this study is to estimate high temporal and high spatial resolution land surface temperature (LST) over different surface types in urban regions. The goal is to estimate high resolution LST by combining Landsat 8 and the Geostationary Operational Environmental Satellite-R Series (GOES-R) infrared-based LST. Landsat 8 provides higher spatial resolution (30 m) estimates of skin temperature every 16 days. However, GOES-R which has lower spatial resolution (2 km) has much higher temporal resolution (5 min). The research project aims to match the dates that both GOES-R and Landsat LSTs to find their spatial relationship to develop the downscaling of GOES-R LST. The downscaling approach will account for systematic biases between Landsat and GOES-R LST products.
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- 2019
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12. Analysis of Surface Temperature Trends of World’s Major Lakes and their Relationship with Land Cover Changes
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Sergio Carrillo, H. Norouzi, A. R. Bah, Reginald Blake, Ronaldo Carhuaricra, Christopher Beale, Cho May Than, and P. Arunyavikul
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0301 basic medicine ,Driving factors ,Data products ,Land surface temperature ,Land cover ,Latitude ,Lake water ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Water temperature ,Environmental science ,Moderate-resolution imaging spectroradiometer ,Physical geography ,030217 neurology & neurosurgery - Abstract
In this study, the world first major 305 lakes have been investigated. An analysis of surface temperature variation over the global lakes have been conducted using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). MODIS Land Surface Temperature (LST) provides surface temperature data twice a day since 2002. The data products were first processed to obtain the average daily temperature over the lakes and their surrounding land areas from July 2002 to May 2018. A statistical approach was applied to calculate the temperature trends of the lake water, the surrounding land. Moreover, the relationship between the LST trends and potential driving factors such as the land cover changes in the lakes’ basins, lakes areas, depth, and latitude were investigated. The primary results show that lakes water temperature are warming faster than the surrounding land temperature. Furthermore, 67.54% of lakes are shrinking while 24.92% are growing.
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- 2019
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13. An adaptive wavelet packet denoising algorithm for enhanced active acoustic damage detection from wind turbine blades
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Christopher Niezrecki, Christopher Beale, and Murat Inalpolat
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0209 industrial biotechnology ,Computer science ,Noise (signal processing) ,Mechanical Engineering ,Noise reduction ,Aerospace Engineering ,Condition monitoring ,02 engineering and technology ,01 natural sciences ,Computer Science Applications ,Wavelet packet decomposition ,020901 industrial engineering & automation ,Wavelet ,Signal-to-noise ratio ,Control and Systems Engineering ,0103 physical sciences ,Signal Processing ,Electronic engineering ,Structural health monitoring ,Time domain ,010301 acoustics ,Civil and Structural Engineering - Abstract
The development of a viable structural health monitoring (SHM) technology for the operational condition monitoring of wind turbine blades is of great interest to the wind industry. In order for any SHM technology to achieve the technical readiness and performance required for an operational implementation, advanced signal processing algorithms need to be developed to adaptively remove noise and retain the underlying signals of interest that describe the damage-related information. The wavelet packet transform decomposes a measured time domain signal into a time-frequency representation enabling the removal of noise that may overlap with the signal of interest in time and/or frequency. However, the traditional technique suffers from several assumptions limiting its applicability in an operational SHM environment, where the noise conditions commonly exhibit erratic behavior. Furthermore, an exhaustive number of options exist when selecting the parameters used in the technique with limited guidelines that can help select the most appropriate options for a given application. Appropriately defining the technique tends to be a daunting task resulting in a general avoidance of the approach in the field of SHM. This work outlines an adaptive wavelet packet denoising algorithm applicable to numerous SHM technologies including acoustics, vibrations, and acoustic emission. The algorithm incorporates a blend of non-traditional approaches for noise estimation, threshold selection, and threshold application to augment the denoising performance of real-time structural health monitoring measurements. Appropriate wavelet packet parameters are selected through a simulation considering the trade-off between signal to noise ratio improvement and amount of signal energy retained. The wavelet parameter simulation can be easily replicated to accommodate any SHM technology where the underlying signal of interest is known, as is the case in most active-based approaches including acoustic and wave-propagation techniques. The finalized adaptive wavelet packet algorithm is applied to a comprehensive dataset demonstrating an active acoustic damage detection approach on a ~46 m wind turbine blade. The quality of the measured data and the damage detection performance obtained from simple spectral filtering is compared with the proposed wavelet packet technique. It is shown that the damage detection performance is enhanced in all but one test case by as much as 60%, and the false detection rate is reduced. The approach and the subsequent results presented in this paper are expected to help enable advancement in the performance of several established SHM technologies and identifies the considered acoustics-based SHM approach as a noteworthy option for wind turbine blade structural health monitoring.
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- 2020
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14. A Global Analysis of Land Surface Temperature Diurnal Cycle
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Sergio V. Cortes, H. Norouzi, Z. Sharifnezhadazizi, Christopher Beale, Reginald Blake, and Makini Valentine
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010504 meteorology & atmospheric sciences ,Land surface temperature ,Diurnal temperature variation ,0211 other engineering and technologies ,02 engineering and technology ,Land cover ,Vegetation ,01 natural sciences ,Diurnal cycle ,Climatology ,Range (statistics) ,Environmental science ,Moderate-resolution imaging spectroradiometer ,Scale (map) ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
Diurnal variations of land surface temperature (LST) have a significant role in a wide range of applications. This study used a fifteen-year series (January 2003 to December 2017) daily observation of LST from MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on board the Aqua and Terra satellites. A spline interpolation method was applied to each year's data to estimate the LST every 30 minutes. The diurnal cycle of LST is computed from the spatially and temporally consistent data at a global scale. The diurnal temperature range and time of occurrence of maximum hour is also calculated for each pixel. The trend of these parameters is compared to a 10-class land cover vegetation and fairly acceptable correlation is found. Analysis of fifteen years diurnal LST record shows a variant global decrease in DTR, but with a few point having increase in amplitude especially in Southern Africa and South America.
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- 2018
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15. The High Temporal Detection of Land Surface Freeze and Thaw States via a Combination of Passive Microwave Estimates
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M. Azarderakhsh, Reginald Blake, Hamidi Norouzi, Satya Prakash, and Christopher Beale
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Radiometer ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,02 engineering and technology ,Land cover ,01 natural sciences ,Microwave imaging ,Brightness temperature ,Emissivity ,Environmental science ,Special sensor microwave/imager ,Global Precipitation Measurement ,Microwave ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
The states of the Earth surface in terms of high-latitude freeze and thaw (FT) cycles significantly impact many physical applications that include biogeochemical transitions, hydrological phenomena, and ecosystem evolution. We have shown that land surface emissivity estimates have great potential for use in the detection of FT states since that parameter primarily depends on surface characteristics instead of on direct use of brightness temperatures. This study aims to investigate the potential of merging passive microwave sensors and their land surface emissivity estimates from Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E), Special Sensor Microwave Imager (SSM/I), AMSR2, and the Global Precipitation Measurement (GPM) Microwave Imager (GMI) to provide high temporal resolution (sub-daily) FT states. This factor is of critical importance and usage, primarily during the transitions between freeze and thaw that frequently occur at sub-daily time-frames in spring seasons. Data fusion techinques were used to construct diurnal estimates in order to accurately predicting the exact time of the freeze-thaw transition for a variety of land cover types and geographical regions. The results revealed that emissivity difference values between low and high frequencies (such as 10.7 GHz and 89GHz) at horizontal polarization from multiple platforms have a strong correlation with ground-based soil temperature diurnal values at 5-cm depth. Evaluation of the proposed approach with independent ground observations from year 2015 to 2017 showed that the data fusion of land surface emissivities in high-latitudes was able to notably capture the frequent FT transitions.
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- 2018
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16. Wind Turbine Blade Damage Detection Using Supervised Machine Learning Algorithms
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Murat Inalpolat, Taylor Regan, and Christopher Beale
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Engineering ,Damage detection ,Wind power ,Turbine blade ,business.industry ,020209 energy ,Feature extraction ,General Engineering ,food and beverages ,Feature selection ,02 engineering and technology ,Machine learning ,computer.software_genre ,01 natural sciences ,law.invention ,Support vector machine ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Structural health monitoring ,Artificial intelligence ,business ,010301 acoustics ,computer - Abstract
Wind turbine blades undergo high operational loads, experience variable environmental conditions, and are susceptible to failure due to defects, fatigue, and weather-induced damage. These large-scale composite structures are fundamentally enclosed acoustic cavities and currently have limited, if any, structural health monitoring (SHM) in place. A novel acoustics-based structural sensing and health monitoring technique is developed, requiring efficient algorithms for operational damage detection of cavity structures. This paper describes the selection of a set of statistical features for acoustics-based damage detection of enclosed cavities, such as wind turbine blades, as well as a systematic approach used in the identification of competent machine learning algorithms. Logistic regression (LR) and support vector machine (SVM) methods are identified and used with optimal feature selection for decision-making via binary classification algorithms. A laboratory-scale wind turbine with hollow composite blades was built for damage detection studies. This test rig allows for testing of stationary or rotating blades, of which time and frequency domain information can be collected to establish baseline characteristics. The test rig can then be used to observe any deviations from the baseline characteristics. An external microphone attached to the tower will be utilized to monitor blade health while blades are internally ensonified by wireless speakers. An initial test campaign with healthy and damaged blade specimens is carried out to arrive at several conclusions on the detectability and feature extraction capabilities required for damage detection.
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- 2017
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17. A novel optical investigation technique for railroad track inspection and assessment
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Christopher Niezrecki, Christopher Beale, and Alessandro Sabato
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Ballast ,Digital image correlation ,Machine vision ,Computer science ,business.industry ,Real-time computing ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Vertical deflection ,Image processing ,02 engineering and technology ,Track (rail transport) ,01 natural sciences ,010309 optics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Structural health monitoring ,Artificial intelligence ,business - Abstract
Track failures due to cross tie degradation or loss in ballast support may result in a number of problems ranging from simple service interruptions to derailments. Structural Health Monitoring (SHM) of railway track is important for safety reasons and to reduce downtime and maintenance costs. For this reason, novel and cost-effective track inspection technologies for assessing tracks’ health are currently insufficient and needed. Advancements achieved in recent years in cameras technology, optical sensors, and image-processing algorithms have made machine vision, Structure from Motion (SfM), and three-dimensional (3D) Digital Image Correlation (DIC) systems extremely appealing techniques for extracting structural deformations and geometry profiles. Therefore, optically based, non-contact measurement techniques may be used for assessing surface defects, rail and tie deflection profiles, and ballast condition. In this study, the design of two camera-based measurement systems is proposed for crossties-ballast condition assessment and track examination purposes. The first one consists of four pairs of cameras installed on the underside of a rail car to detect the induced deformation and displacement on the whole length of the track’s cross tie using 3D DIC measurement techniques. The second consists of another set of cameras using SfM techniques for obtaining a 3D rendering of the infrastructure from a series of two-dimensional (2D) images to evaluate the state of the track qualitatively. The feasibility of the proposed optical systems is evaluated through extensive laboratory tests, demonstrating their ability to measure parameters of interest (e.g. crosstie’s full-field displacement, vertical deflection, shape, etc.) for assessment and SHM of railroad track.
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- 2017
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18. Correction: Tantalum(<scp>v</scp>) 1,3-propanediolate β-diketonate solution as a precursor to sol–gel derived, metal oxide thin films
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Stefanie Hamacher, Elmar Neumann, Alexander Shkurmanov, Gregor Mussler, Sören Möller, Guillermo Beltramo, Alexey Yakushenko, Oumaima Bensaid, Heinrich Hartmann, Christopher Beale, Sabine Willbold, Dirk Mayer, Bernhard Wolfrum, and Andreas Offenhäusser
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Materials science ,General Chemical Engineering ,Tantalum ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Metal oxide thin films ,0104 chemical sciences ,chemistry ,0210 nano-technology ,Nuclear chemistry ,Sol-gel - Abstract
Correction for ‘Tantalum(v) 1,3-propanediolate β-diketonate solution as a precursor to sol–gel derived, metal oxide thin films’ by Christopher Beale et al., RSC Adv., 2020, 10, 13737–13748, DOI: 10.1039/D0RA02558E.
- Published
- 2020
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19. ABSORPTION CROSS SECTIONS OF HOT HYDROCARBONS IN THE 3 μm REGION
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Christopher Beale, Peter Bernath, Eric Buzan, and Robert Hargreaves
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Materials science ,Analytical chemistry ,Atomic physics ,Absorption (electromagnetic radiation) - Published
- 2016
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20. LINE LISTS AND ASSIGNMENTS OF HOT AMMONIA IN THE INFRARED
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Christopher Beale, Peter Bernath, Andy Wong, and Robert Hargreaves
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Line list ,Ammonia ,chemistry.chemical_compound ,Chemistry ,Infrared ,Analytical chemistry - Published
- 2016
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21. An experimental investigation into the insertion loss from subscale acoustic enclosures with geometric imperfections
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Christopher Niezrecki, Murat Inalpolat, Christopher Beale, and David J. Willis
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0209 industrial biotechnology ,Cuboid ,Acoustics and Ultrasonics ,Anechoic chamber ,Turbine blade ,Acoustics ,Enclosure ,02 engineering and technology ,Edge (geometry) ,01 natural sciences ,law.invention ,020901 industrial engineering & automation ,Arts and Humanities (miscellaneous) ,Fuselage ,law ,0103 physical sciences ,Insertion loss ,Loudspeaker ,010301 acoustics ,Geology - Abstract
Enclosures with different geometries constitute the internal sections of various engineering applications including cabins of passenger cars, fuselages of aircraft wings, and internal compartments of wind turbine blades. Acoustic insertion loss from and to these enclosures affect certain objective and subjective acoustic measures along with the ability to detect damage. This presentation describes a thoroughly executed test plan that identifies the effect of geometric imperfections, such as holes, edge splits, and cracks with different severity levels and locations, on the insertion loss from a subscale acoustic enclosure. A composite rectangular prism enclosure, located inside an anechoic chamber, was internally ensonified using a loudspeaker, and an externally located condenser microphone was used to measure the insertion loss under different conditions. One of the faces of the enclosure possessed various size and location imperfections simulating damage. Insertion loss deviations introduced through the...
- Published
- 2017
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