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Zeitschriftenartikel zum Thema "LSWT"
1
Zhang, Xin, Kaicun Wang, Marieke A. Frassl, and Bertram Boehrer. "Reconstructing Six Decades of Surface Temperatures at a Shallow Lake." Water 12, no. 2 (2020): 405. http://dx.doi.org/10.3390/w12020405.
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Lake surface water temperature (LSWT) plays a fundamental role in the lake energy budget. However, direct observations of LSWT require considerable effort for acquisition and hence are rare relative to a large number of lakes. In lakes where LSWT has not been covered sufficiently by in situ measurements, remote sensing and lake modeling can be used to produce a fine spatio-temporal record of LSWTs. In our study, the Moderate-Resolution Imaging Spectroradiometer (MODIS) LSWT was used to compare with in situ data at the overpass times over the six sites in Lake Chaohu, a large shallow lake in China. MODIS-derived LSWT reflected the variation of lake surface temperature well, with a correlation coefficient of 0.96 and a cool bias of 1.25 °C. The bias was modified by an “Upper Envelop” smoothing method and then employed to evaluate the general lake model (GLM) performance, a one-dimensional hydrodynamic model. The GLM simulations showed good performance compared with MODIS LSWT data at an interannual time scale. A 57-year record of simulated LSWT was hindcast by the well-calibrated GLM for Lake Chaohu. The results showed that LSWT decreased by 0.08 °C/year from 1960 to 1981 and then increased by 0.05 °C/year. These trends were most likely caused by a cooling effect of decreased surface incident solar radiation and a warming effect of reduced wind speed. Our study promoted the use of MODIS-derived LSWT as an alternative data source, and then combined with a numerical model for inland water surface temperature, and also further provided an understanding of climate warming effect on such a shallow eutrophic lake. Key points: (1) Moderate-Resolution Imaging Spectroradiometer (MODIS) lake water surface temperature (LSWT) was validated with real-time in situ data collected at Lake Chaohu with high accuracy; (2) MODIS LSWT was modified by the bias correction and employed to evaluate a one-dimensional lake model at interannual and intraannual scale; The LSWT hindcast by a well-calibrated model at Lake Chaohu decreased by 0.08 °C/year from 1960 to 1981 and increased by 0.05 °C/year from 1982 to 2016.
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Layden, A., S. MacCallum, and C. Merchant. "Determining lake surface water temperatures (LSWTs) worldwide using a tuned 1-dimensional lake model (<i>FLake</i>, v1)." Geoscientific Model Development Discussions 8, no. 10 (2015): 8547–606. http://dx.doi.org/10.5194/gmdd-8-8547-2015.
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Abstract. FLake, a 1-dimensional freshwater lake model, is tuned for 244 globally distributed large lakes using lake surface water temperatures (LSWTs) derived from Along-Track Scanning Radiometers (ATSRs). The model, tuned using only 3 lake properties; lake depth, albedo (snow and ice) and light extinction co-efficient, substantially improves the measured biases in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes. The daily mean absolute differences (MAD) and the spread of differences (±2 standard deviations) across the trial seasonally ice covered lakes (lakes with a lake-mean LSWT remaining below 1 °C for part of the annual cycle) is reduced from 3.01± 2.25 °C (pre-tuning) to 0.84 ± 0.51 °C (post-tuning). For non-seasonally ice-covered trial lakes (lakes with a lake-mean LSWT remaining above 1 °C throughout its annual cycle), the average daily mean absolute difference (MAD) is reduced from 3.55 ± 3.20 °C to 0.96 ± 0.63 °C. The post tuning results for the trial lakes (35 lakes) are highly representative of the post tuning results of the 244 lakes. The sensitivity of the summer LSWTs of deeper lakes to changes in the timing of ice-off is demonstrated. The modelled summer LSWT response to changes in ice-off timing is found to be strongly affected by lake depth and latitude, explaining 0.50 (R2adj, p = 0.001) of the inter-lake variance in summer LSWTs. Lake depth alone explains 0.35 (p =0.003) of the variance. The tuning approach undertaken in this study, overcomes the obstacle of the lack of available lake characteristic information (snow and ice albedo and light extinction co-efficient) for individual lakes. Furthermore, the tuned values for lake depth, snow and ice albedo and light extinction co-efficient for the 244 lakes provide guidance for improving LSWTs modelling in FLake.
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Yu, Soon-Ju, Ju-Yeon Son, Ho-Yeong Kang, Yong-Chul Cho, and Jong-Kwon Im. "Effects of Long-Term Increases in Water Temperature and Stratification on Large Artificial Water-Source Lakes in South Korea." Water 13, no. 17 (2021): 2341. http://dx.doi.org/10.3390/w13172341.
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Long-term changes in air and water temperatures and the resulted stratification phenomena were observed for Soyang Lake (SY), Paldang Lake (PD), Chungju Lake (CJ), and Daecheong Lake (DC) in South Korea. Non-parametric seasonal Kendall and Mann-Kendall tests, Sen slope estimator, and potential energy anomaly (PEA) were applied. The lake surface water temperatures (LSWTs) of SY and DC increased at the same rate (0.125 °C/y), followed by those of CJ (0.071 °C/y) and PD (0.06 °C/y). Seasonally, the LSWT increase rates for all lakes, except PD, were 2–3 times higher than the air temperature increase rates. The lake stratification intensity order was similar to those of the LSWT increases and correlations. SY and DC displayed significant correlations between LSWT (0.99) and PEA (0.91). Thus, the LSWT significantly affected stratification when the water temperature increased. PD demonstrated the lowest correlation between LSWT and PEA. Inflow, outflow, rainfall, wind speed, and retention time were significantly correlated, which varied within and between lakes depending on lake topographical, hydraulic, and hydrological factors. Thus, hydraulic problems and nutrients should be managed to minimize their effects on lake water quality and aquatic ecosystems because lake cyanobacteria can increase as localized water temperatures increase.
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Layden, Aisling, Stuart N. MacCallum, and Christopher J. Merchant. "Determining lake surface water temperatures worldwide using a tuned one-dimensional lake model (<i>FLake</i>, v1)." Geoscientific Model Development 9, no. 6 (2016): 2167–89. http://dx.doi.org/10.5194/gmd-9-2167-2016.
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Abstract. A tuning method for FLake, a one-dimensional (1-D) freshwater lake model, is applied for the individual tuning of 244 globally distributed large lakes using observed lake surface water temperatures (LSWTs) derived from along-track scanning radiometers (ATSRs). The model, which was tuned using only three lake properties (lake depth, snow and ice albedo and light extinction coefficient), substantially improves the measured mean differences in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes, when compared to the observed LSWTs. Lakes whose lake-mean LSWT persists below 1 °C for part of the annual cycle are considered to be seasonally ice-covered. For trial seasonally ice-covered lakes (21 lakes), the daily mean and standard deviation (2σ) of absolute differences between the modelled and observed LSWTs are reduced from 3.07 °C ± 2.25 °C to 0.84 °C ± 0.51 °C by tuning the model. For all other trial lakes (14 non-ice-covered lakes), the improvement is from 3.55 °C ± 3.20 °C to 0.96 °C ± 0.63 °C. The post tuning results for the 35 trial lakes (21 seasonally ice-covered lakes and 14 non-ice-covered lakes) are highly representative of the post-tuning results of the 244 lakes. For the 21 seasonally ice-covered lakes, the modelled response of the summer LSWTs to changes in snow and ice albedo is found to be statistically related to lake depth and latitude, which together explain 0.50 (R2adj, p = 0.001) of the inter-lake variance in summer LSWTs. Lake depth alone explains 0.35 (p = 0.003) of the variance. Lake characteristic information (snow and ice albedo and light extinction coefficient) is not available for many lakes. The approach taken to tune the model, bypasses the need to acquire detailed lake characteristic values. Furthermore, the tuned values for lake depth, snow and ice albedo and light extinction coefficient for the 244 lakes provide some guidance on improving FLake LSWT modelling.
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Aslan, N., and D. Koc-San. "INVESTIGATION OF THE CHANGES OF LAKE SURFACE TEMPERATURES AND AREAS: CASE STUDY OF BURDUR AND EGIRDIR LAKES, TURKEY." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2021 (June 28, 2021): 299–304. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2021-299-2021.
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Abstract. The world's average surface temperature has been increasing in recent decades. This situation is expected to affect aquatic systems and lakes are one of the most important aquatic systems. The main aims of this study are to examine Lake Surface Water Temperature (LSWT) and area changes of Burdur and Egirdir lakes located in the West Mediterranean Region (TR61) of Turkey for the years 1998, 2008 and 2018 using Landsat satellite images. For this purpose, initially, Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) images were generated and the lake shorelines were extracted by thresholding these images. Then, the LSWT values were obtained by using Landsat thermal images. Finally, the area and LSWT changes of Burdur and Egirdir lakes between the years 1998-2008-2018 and the relationships of these parameters with each other were analysed. The obtained results showed that the lake boundaries could be semi-automatically extracted with overall accuracy values higher than 95%. In 20-year time period it was also observed that the Burdur Lake area decreased significantly, while the Egirdir Lake area decreased slightly. When the LSWT values were analysed, it can be stated that the LSWT values increased in both lakes during this time period. The amount of increase in LSWT values was about 2.2 °C for Burdur Lake, while about 1.3 °C for Egirdir Lake.
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Tavares, Matheus, Augusto Cunha, David Motta-Marques, et al. "Comparison of Methods to Estimate Lake-Surface-Water Temperature Using Landsat 7 ETM+ and MODIS Imagery: Case Study of a Large Shallow Subtropical Lake in Southern Brazil." Water 11, no. 1 (2019): 168. http://dx.doi.org/10.3390/w11010168.
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Water temperature regulates many processes in lakes; therefore, evaluating it is essential to understand its ecological status and functioning, and to comprehend the impact of climate change. Although few studies assessed the accuracy of individual sensors in estimating lake-surface-water temperature (LSWT), comparative analysis considering different sensors is still needed. This study evaluated the performance of two thermal sensors, MODIS and Landsat 7 ETM+, and used Landsat methods to estimate the SWT of a large subtropical lake. MODIS products MOD11 LST and MOD28 SST were used for comparison. For the Landsat images, the radiative transfer equation (RTE), using NASA’s Atmospheric Correction Parameter Calculator (AtmCorr) parameters, was compared with the single-channel algorithm in different approaches. Our results showed that MOD11 obtained the highest accuracy (RMSE of 1.05 ° C), and is the recommended product for LSWT studies. For Landsat-derived SWT, AtmCorr obtained the highest accuracy (RMSE of 1.07 ° C) and is the recommended method for small lakes. Sensitivity analysis showed that Landsat-derived LSWT using the RTE is very sensitive to atmospheric parameters and emissivity. A discussion of the main error sources was conducted. We recommend that similar tests be applied for Landsat imagery on different lakes, further studies on algorithms to correct the cool-skin effect in inland waters, and tests of different emissivity values to verify if it can compensate for this effect, in an effort to improve the accuracy of these estimates.
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Riffler, M., and S. Wunderle. "Lake surface water temperatures of European Alpine lakes (1989–2013) based on the Advanced Very High Resolution Radiometer (AVHRR) 1 km data set." Earth System Science Data Discussions 7, no. 1 (2014): 305–34. http://dx.doi.org/10.5194/essdd-7-305-2014.
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Abstract. Lake water temperature (LWT) is an important driver of lake ecosystems and it has been identified as an indicator of climate change. Thus, the Global Climate Observing System (GCOS) lists LWT as an Essential Climate Variable (ECV). Although for some European lakes long in situ time series of LWT do exist, many lakes are not observed or only on a non-regular basis making these observations insufficient for climate monitoring. Satellite data can provide the information needed. However, only few satellite sensors offer the possibility to analyse time series which cover 25 years or more. The Advanced Very High Resolution Radiometer (AVHRR) is among these and has been flown as a heritage instrument for almost 35 years. It will be carried on for at least ten more years finally offering a unique opportunity for satellite-based climate studies. Herein we present a satellite-based lake surface water temperature (LSWT) data set for European (pre-alpine) water bodies based on the extensive AVHRR 1 km data record (1989–2013) of the Remote Sensing Research Group at the University of Bern. It has been compiled out of AVHRR/2 (NOAA-07, -09, -11, -14) and AVHRR/3 (NOAA-16, -17, -18, -19 and Metop-A) data. The high accuracy needed for climate related studies requires careful pre-processing and consideration of the atmospheric state. Especially data from NOAA-16 and prior satellites were prone to noise, e.g., due to transmission errors or fluctuations in the instrument's thermal state. This has resulted in partly corrupted thermal calibration data and may cause errors of up to several Kelvin in the final resulting LSWT. Thus, a multi-stage correction scheme has been applied to the data to minimize these artefacts. The LSWT retrieval is based on a simulation-based scheme making use of the Radiative Transfer for TOVS (RTTOV) Version 10 together with operational analysis and reanalysis data from the European Centre for Medium Range Weather Forecasts. The resulting LSWTs were extensively validated using in situ measurements from lakes with various sizes between 14 and 580 km2 and the resulting biases and RMSEs were found to be within the range of −0.4–0.6 K and 1.0–1.9 K, respectively. The upper limits of the reported errors could be rather attributed to uncertainties in the data comparison between in situ and satellite observations than inaccuracies of the satellite retrieval. The cross-platform consistency of the retrieval was found to be within ~0.2 K. A comparison with LSWT derived through global sea surface temperature (SST) algorithms shows lower RMSEs and biases for the simulation-based approach. A running project will apply the developed method to retrieve LSWT from the northern part of Finland to southern Italy to derive the climate signal of the last 30 years. The data are available at doi:10.1594/PANGAEA.831007.
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Dye, Adrian, Robert Bryant, Emma Dodd, Francesca Falcini, and David M. Rippin. "Warm Arctic Proglacial Lakes in the ASTER Surface Temperature Product." Remote Sensing 13, no. 15 (2021): 2987. http://dx.doi.org/10.3390/rs13152987.
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Despite an increase in heatwaves and rising air temperatures in the Arctic, little research has been conducted into the temperatures of proglacial lakes in the region. An assumption persists that they are cold and uniformly feature a temperature of 1 °C. This is important to test, given the rising air temperatures in the region (reported in this study) and potential to increase water temperatures, thus increasing subaqueous melting and the retreat of glacier termini from where they are in contact with lakes. Through analysis of ASTER surface temperature product data, we report warm (>4 °C) proglacial lake surface water temperatures (LSWT) for both ice-contact and non-ice-contact lakes, as well as substantial spatial heterogeneity. We present in situ validation data (from problematic maritime areas) and a workflow that facilitates the extraction of robust LSWT data from the high-resolution (90 m) ASTER surface temperature product (AST08). This enables spatial patterns to be analysed in conjunction with surrounding thermal influences, such as parent glaciers and topographies. This workflow can be utilised for the analysis of the LSWT data of other small lakes and crucially allows high spatial resolution study of how they have responded to changes in climate. Further study of the LSWT is essential in the Arctic given the amplification of climate change across the region.
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White, Charles, Andrew Heidinger, Steven Ackerman, and Peter McIntyre. "A Long-Term Fine-Resolution Record of AVHRR Surface Temperatures for the Laurentian Great Lakes." Remote Sensing 10, no. 8 (2018): 1210. http://dx.doi.org/10.3390/rs10081210.
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Inland waters are warming at highly variable rates that often differ from regional air temperature trends. This variable warming is partially attributable to an individual lake’s geographical and morphological characteristics. In very large lakes, significant intralake variability in long-term warming trends has also been observed. In light of this intralake and interlake heterogeneity of lake surface water temperature (LSWT) and LSWT trends, we revisit the 1.1 km Advanced Very High Resolution Radiometer (AVHRR) record for the Laurentian Great Lakes. In this work, we have assembled a long-term (1986–2016) and high-spatial-resolution (0.018°) daily LSWT dataset using AVHRR record. Subtracting an empirically-determined mean diurnal cycle mitigates the effects of varying observation times. Adjustments in the georegistration of the images are made to reduce the impact of AVHRR navigational errors on the earlier platforms. Both the original daily composites, and a gap-filled product using locally weighted interpolation methods will be made available to support fine-scale physical and environmental research in the region.
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Rontu, Laura, Kalle Eerola, and Matti Horttanainen. "Validation of lake surface state in the HIRLAM v.7.4 numerical weather prediction model against in situ measurements in Finland." Geoscientific Model Development 12, no. 8 (2019): 3707–23. http://dx.doi.org/10.5194/gmd-12-3707-2019.
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Abstract. The High Resolution Limited Area Model (HIRLAM), used for the operational numerical weather prediction in the Finnish Meteorological Institute (FMI), includes prognostic treatment of lake surface state since 2012. Forecast is based on the Freshwater Lake (FLake) model integrated into HIRLAM. Additionally, an independent objective analysis of lake surface water temperature (LSWT) combines the short forecast of FLake to observations from the Finnish Environment Institute (SYKE). The resulting description of lake surface state – forecast FLake variables and analysed LSWT – was compared to SYKE observations of lake water temperature, freeze-up and break-up dates, and the ice thickness and snow depth for 2012–2018 over 45 lakes in Finland. During the ice-free period, the predicted LSWT corresponded to the observations with a slight overestimation, with a systematic error of +0.91 K. The colder temperatures were underrepresented and the maximum temperatures were too high. The objective analysis of LSWT was able to reduce the bias to +0.35 K. The predicted freeze-up dates corresponded well to the observed dates, mostly within the accuracy of a week. The forecast break-up dates were far too early, typically several weeks ahead of the observed dates. The growth of ice thickness after freeze-up was generally overestimated. However, practically no predicted snow appeared on lake ice. The absence of snow, presumably due to an incorrect security coefficient value, is suggested to be also the main reason for the inaccurate simulation of the lake ice melting in spring.
Dissertationen zum Thema "LSWT"
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Layden, Aisling. "Global study of lake surface water temperature (LSWT) behaviour and the tuning of a 1-dimensional model to determine the LSWTs of large lakes worldwide." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9928.
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Lake surface water temperatures (LSWTs) of 246 globally distributed large lakes were derived from Along-Track Scanning Radiometers (ATSR) for the period 1991 to 2011. These LSWTs, derived in a systematic manner, presents an ideal opportunity to study LSWT behaviour on a global scale. In this thesis, the annual cycles of lake-mean LSWTs derived from these data quantify the responses of large lakes’ surface temperatures to the annual cycle of forcing by solar radiation and the ambient air temperature. Minimum monthly net surface solar irradiance (netSSI) strongly influences minimum LSWTs of non-seasonally ice covered lakes (where lake-mean LSWT remains above 1 ºC throughout the annual cycle), explaining > 0.88 (R2 adj) of the inter-lake variation in both hemispheres. In some regions, for seasonally ice covered lakes (where lake-mean LSWT remains below 1 ºC for part of the annual cycle) the minimum monthly netSSI is a better predictor than latitude, of the length of the frozen period, which shows the importance of local cloud climatological conditions. Additionally, at lake locations between 1º S to 12º N, the netSSI, shown to peak twice annually, is reflected in the LSWT annual cycle. The summer maximum LSWTs of lakes from 25º S to 35º N show a linear decrease with increasing altitude; -3.76 + 0.17 ºC km-1 (R2 adj = 0.95), marginally lower than the corresponding air temperature -4.15 + 0.24 ºC km-1 (R2 adj = 0.95) decrease with altitude. The start and end of the period where the lake-mean LSWT is greater than 4 ºC shows strong correlation with the spring and autumn 0 ºC air temperature crossing days, (R2 adj = 0.74 and 0.80 respectively). The temporally and spatially resolved LSWT observations allows for a greater practical understanding of LSWT behaviour of large lakes. For example, lakes with a greater LSWT annual range have more observed variability in the LSWT extremes, highlighting that they may be more responsive to changes in the climate than lakes with a low annual range. The nighttime LSWT trends show stronger warming than day-night trends in the all regions, except Europe. The lake centre LSWT trends and absolute values can be generally considered representative of the lake-mean LSWT trends and absolute values. The observed LSWT time series are used to tune a 1-dimensional thermodynamic lake model, FLake. By tuning FLake using only 3 basic lake properties, shown by myself to have the most influence over LSWTs (depth, snow and ice albedo and light extinction co-efficient), the daily mean absolute differences for 244 lakes is reduced from 3.38 + 2.74 ºC (untuned model) to 0.85 + 0.61 ºC (tuned model). The effect of wind speed, lake depth, albedo and light extinction co-efficient on LSWTs is demonstrated throughout the tuning process. The modelled summer LSWT response to changes in ice-off is strongly affected by lake depth and latitude explaining 0.50 (R2 adj, p = 0.001) of the inter-lake variation in summer LSWTs. Lake depth alone explains 0.35 (p = 0.003) of the variation, highlighting the sensitivity of the summer LSWTs of deeper lakes to changes in the ice-off. Statistically significant summer/ maximum month modelled LSWT trends, from 1979-2011 are presented for lakes where the modelled LSWTs are strongly supported by observed LSWTs over the period of available observed LSWTs. For these lakes, the trends show LSWT warming of between 0.73 – 2.10 ºC for 29 lakes in northern temperate regions over the 33 year period (1979 – 2011). The modelled regional trends of all lakes over the same period show least warming in Africa of 0.30 ºC and the greatest warming in Europe, 1.35 º.
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Horton, Damien. "Development of an Infrared Thermography System to Measure Boundary Layer Transition in a Low Speed Wind Tunnel Testing Environment." DigitalCommons@CalPoly, 2021. https://digitalcommons.calpoly.edu/theses/2287.
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The use of infrared thermography for boundary layer detection was evaluated for use in the Cal Poly Low Speed Wind Tunnel (LSWT) and recommendations for the successful use of this technique were developed. In cooperation with Joby Aviation, an infinite wing model was designed, manufactured and tested for use in the LSWT. The wing was designed around a custom airfoil profile specific for this project, where the nearly-flat pressure gradient at a zero pitch angle would delay the chordwise onset of boundary layer transition. Steady-state, RANS numerical simulations predicted the onset of transition to occur at 0.75 x/c for the design Reynolds Number condition of 6.25x105. The wing was manufactured from 3D printed aluminum, with a wall thickness of 0.125 inches and a chord length of 13.78 inches. Two central rows of static pressure taps were used, each with 12 functional chordwise locations. The taps were able to generate strong correlation to the numerically predicted pressure coefficient distribution.
The use of an infrared camera visualized and confirmed the presence of boundary layer transition at the chordline location anticipated by the early simulations. To do so, the model was pre-heated such that the differential cooling properties of laminar and turbulent flow would generate a clear temperature gradient on the surface correlating to boundary layer transition. Adjustment of the model’s pitch angle demonstrated a change in the onset location of boundary layer transition during the infrared testing. The change of onset location was seen to move forward along the chordline as the aerodynamic angle of attack was increased. Testing with a Preston Tube system allowed for the interpolation of local skin friction coefficient values at each static tap location. Application of both laminar and turbulent empirical assumptions, when compared to numerical expectations, allowed for the qualitative assessment of boundary layer transition onset. Overall, the wing model developed for this research proved capable of producing quality and repetitive results for the experimental goals it was designed to meet. The model will next be used in continued tests which will further explore the use of infrared thermography.
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Sebag, J., W. Gressler, M. Liang, et al. "LSST primary/tertiary monolithic mirror." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622513.
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At the core of the Large Synoptic Survey Telescope (LSST) three-mirror optical design is the primary/tertiary (M1M3) mirror that combines these two large mirrors onto one monolithic substrate. The M1M3 mirror was spin cast and polished at the Steward Observatory Mirror Lab at The University of Arizona (formerly SOML, now the Richard F. Caris Mirror Lab at the University of Arizona (RFCML)). Final acceptance of the mirror occurred during the year 2015 and the mirror is now in storage while the mirror cell assembly is being fabricated. The M1M3 mirror will be tested at RFCML after integration with its mirror cell before being shipped to Chile.
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Petitdidier, Nils. "LSST: Characterization of the CCD sensors." Thesis, KTH, Tillämpad fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168008.
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Boussard, Fanny, and Natali Bethoon. "Röstbehandling med LSVT LOUD för personer med cerebral pares och dysartri." Thesis, Uppsala universitet, Blom Johansson: Logopedi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-403640.
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Approximately 50 % of all people with cerebral palsy (CP) have some form of speech or language disorder. Many of these have dysarthria, a neurological disorder that causes an impaired ability to articulate and effects respiration and phonation. Many people with CP consider dysarthria to be the biggest impairment as it has a major impact on their communication. Despite this there are limited voice and speech treatments for this group of patients. The purpose of this study was to evaluate whether treatment of speech and voice functions with intensive voice treatment (LSVT LOUD) can improve the speech intelligibility in patients with dysarthria secondary to CP. Five participants (3 male and 2 female) were recruited and underwent 16 one-hour sessions of intensive voice treatment. A single-case experimental design (SCED) was used and testing occurred two weeks prior to (PRE), during (TREAT) and immediately following (POST) treatment. Measures of sound pressure level (SPL) in decibel (dB) and speech intelligibility on word and sentence level were conducted, alongside perceptual ratings of voice quality. Before and after treatment, participants answered a self-response form to evaluate their speech and communication. In addition to this the participants also estimated how effortful the treatment was. The results showed improvement in speech intelligibility and increased dB SPL on word and sentence level for four of the five participants. Perceptual ratings showed minor improvements in voice quality. Two out of five participants rated an improvement in their speech and communication. Overall the participants estimated the treatment as “very strenuous”. This study has contributed knowledge about the effects of LSVT LOUD on a new age group of people with dysarthria secondary to CP. More research is needed to draw conclusions on the effects of LSVT LOUD on speech intelligibility for people with dysarthria secondary to CP.<br>Ungefär 50 % av alla personer med cerebral pares (CP) har någon form av tal- eller språksvårighet. Många av dessa har dysartri, vilket innebär nedsatt artikulationsförmåga samt påverkan på andning och fonation till följd av neurologisk skada. Många personer med CP anser att dysartri är den största funktionsnedsättningen då den försvårar kommunikationen. Trots detta saknas utvärderade tal- och röstbehandlingsmetoder för patientgruppen. Syftet med denna studie var att undersöka om behandling av tal- och röstfunktionen med intensiv röstbehandling (LSVT LOUD) kan påverka talförståeligheten för patienter med dysartri sekundärt till CP. Fem deltagare rekryterades (3 manliga och 2 kvinnliga): dessa genomgick 16 behandlingssessioner med intensiv röstbehandling á 1 timme. Till studien användes en single-case experimental design (SCED) där testning utfördes två veckor innan (PRE), under (TREAT) och direkt efter (POST) behandling. Mätningar gjordes på sound pressure level (SPL) i decibel (dB) och talförståelighet på ord - och meningsnivå. Dessutom gjordes perceptuella bedömningar av röstkvaliteten. Innan och efter behandling utvärderades tal- och kommunikationsförmågan genom ett självsvarsformulär. Deltagarna skattade dessutom hur ansträngande de upplevt behandlingsperioden. Behandlingen resulterade i förbättringar för fyra av fem deltagare gällande röststyrka och ökad talförståelighet på ord- och meningsnivå. Perceptuella bedömningar visade på små förbättringar beträffande röstkvalitet. Två av fem deltagare skattade att deras tal- och kommunikationsförmåga förbättrats efter behandling. Generellt sett upplevde deltagarna behandlingen som “väldigt mycket ansträngande”. Studien har bidragit med kunskap om effekten av LSVT LOUD på en ny åldersgrupp av personer med dysartri till följd av CP. Mer forskning behövs för att kunna dra slutsatser om effekten av LSVT LOUD på talförståeligheten för personer med dysartri sekundärt till CP.
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Martin, H. M., J. R. P. Angel, G. Z. Angeli, et al. "Manufacture and final tests of the LSST monolithic primary/tertiary mirror." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622424.
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The LSST M1/M3 combines an 8.4 m primary mirror and a 5.1 m tertiary mirror on one glass substrate. The combined mirror was completed at the Richard F. Caris Mirror Lab at the University of Arizona in October 2014. Interferometric measurements show that both mirrors have surface accuracy better than 20 nm rms over their clear apertures, in near-simultaneous tests, and that both mirrors meet their stringent structure function specifications. Acceptance tests showed that the radii of curvature, conic constants, and alignment of the 2 optical axes are within the specified tolerances. The mirror figures are obtained by combining the lab measurements with a model of the telescope's active optics system that uses the 156 support actuators to bend the glass substrate. This correction affects both mirror surfaces simultaneously. We showed that both mirrors have excellent figures and meet their specifications with a single bending of the substrate and correction forces that are well within the allowed magnitude. The interferometers do not resolve some small surface features with high slope errors. We used a new instrument based on deflectometry to measure many of these features with sub-millimeter spatial resolution, and nanometer accuracy for small features, over 12.5 cm apertures. Mirror Lab and LSST staff created synthetic models of both mirrors by combining the interferometric maps and the small high-resolution maps, and used these to show the impact of the small features on images is acceptably small.
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Posse, Dorothea, and Ulrike Frank. "Der Einfluss des Lee Silverman Voice Treatment (LSVT) auf die Hypernasalität bei Dysarthrie." Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5431/.
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Ciulli, Alexandre. "Cosmologie et supernovas Ia : influence des vitesses propres et recherche d'anisotropies avec LSST." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC072/document.
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Les supernovas de type Ia (SNIa) sont des objets transitoires, observables pour une durée de quelques mois et dont la luminosité à son maximum équivaut à celle d'une galaxie entière. Une fois standardisées (c'est à dire corrigées de leurs principales variabilités), elles représentent, un excellent indicateur de distance et ont permis de mettre en évidence, en 1998, ce que l'on peut représenter comme une accélération de l’expansion de l'Univers. Cette thèse s’intéresse à trois points qui concerne l’étude de la cosmologie par les SNIa :En premier lieu on s'intéresse à la chaîne de production des données et à la qualité des images pour le Large Synoptic Survey Telescope (LSST), qui couvrira un large éventail de domaines scientifique, y compris l'observation des SNIa. Actuellement en préparation pour LSST (dont les observations commenceront en 2020), cette chaîne de production a été testée en effectuant le traitement d’images provenant d’un relevé antérieur (champ profond du CFHT). Les paramètres de qualité astrométriques et photométriques présentent une dispersion légèrement supérieure à celle requise par le cahier de charges du LSST. En ce qui concerne la photométrie, les sources de cette dispersion restent à être comprises. Pour ce qui est de l'astrométrie, la qualité obtenue sera vraisemblablement suffisante lorsque l'ajustement par astrométrie simultanée sera implémenté.Ensuite, on propose une méthode permettant de corriger l'effet induit par les vitesses propres des SNIa se trouvant dans des amas de galaxies. En effet, ces vitesses propres sont particulièrement importantes du fait des interactions gravitationnelles, et perturbent la mesure du décalage spectral cosmologique lié à l'expansion de l'Univers. On a pris en compte un échantillon de 145 SNIa à faible décalage spectral (0,005 < z < 0,123), observées par la collaboration Nearby SuperNova Factory. Parmi ces SNIa, 11 SNIa ont été associées à des amas de galaxies. Ces corrections de vitesses propres ont ainsi permis de diminuer la dispersion sur le diagramme de Hubble de 0,137+/-0,36 mag à 0,130 +/- 0,38 mag, pour les SNIa appartenant à des amas. Bien que le poids de ces corrections soit relativement modeste, on a montré qu'elles sont statistiquement significatives. Ce type de corrections pourraient être prises en considération dans de futures analyses cosmologiques. Enfin on s'intéresse à la question de la détectabilité de possibles anisotropies de l’expansion de l'Univers avec les données de SNIa. Étant donné que la distribution spatiale des données actuelles est connue pour limiter la détection d’une anisotropie dans les distances mesurées des SNIa, on a établi des simulations permettant de déterminer si un effet dipolaire d'amplitude comparable à la borne supérieure des observations actuelles (AD=10-3) pourrait être détecté avec les observations futures du LSST. Plusieurs scénarios ont été considérés, chacun considérant un nombre de SNIa différent. Chacun de ces scénarios est étudié suivant deux variantes correspondant à deux directions, l'une (polaire) pour laquelle la distribution de données de LSST serait la plus symétrique possible, l'autre suivant une direction perpendiculaire à celle-ci (équatoriale). On montre que pour les simulations comportant 5000 SNIa, un dipôle d’amplitude AD=10-3 serait détecté indépendamment de sa direction. On constate que la distance statistique entre les distributions obtenues pour un dipôle simulé et les simulations sans dipôle augmente à mesure que le nombre de SNIa simulées est grand. On constate aussi que cette distance statistique est plus grande pour les dipôles alignés sur la direction équatoriale que pour ceux suivant la direction polaire. (...)<br>Type Ia supernovae (SNIa) are transient objects, which remains observable in the optical for a period of a few months, and whose luminosity at its maximum is comparable to that of a whole galaxy. They represent, once standardized (i.e. corrected for their main variabilities), an excellent distance indicator and, in 1998, provided the first evidence for the acceleration of the expansion of the Universe. This thesis investigates three points in the cosmological SNIa pipeline:First, we focused on the data processing and the quality of the images for the Large Synoptic Survey Telescope (LSST), that will provide data for a number of cosmological observables, including the observation of SNIa. In preparation for LSST (which will start operations in 2020), we carried out a similar data processing strategy on images from a previous survey (deep field of CFHT) and compared to the required parameters of LSST. A dispersion slightly higher than that required was obtained. For photometry, although this excess is small, the sources of this dispersion remain to be understood. For astrometry, the obtained quality is likely to be sufficient when simultaneous astrometry fitting will be implemented.In a second moment, we propose a method to correct the effect of peculiar velocities of SNIa inside galaxy clusters. Indeed, these velocities are more important in the clusters of galaxies, because of the gravitational interactions, and the measurement of the cosmological redshift related to the expansion of the Universe. These peculiar velocities were corrected using a sample of 145 SNIa with a low spectral shift (0.005
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Choyer, Adeline. "Contribution au projet LSST : développement d'un banc de test pour la caméra et étude des oscillaions acousiques de baryons." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY100/document.
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Le télescope LSST (Large Synoptic Survey Telescope) fait partie de la nouvelle générationd'instruments optiques ayant pour objectif la réalisation d'une cartographie complète de l'Univers.Son champ de vue, à la fois large et profond, va conduire à l'observation de milliards d'objets, encouvrant la moitié du ciel dans six bandes photométriques. Les données issues des observationsde LSST vont notamment permettre de contraindre les paramètres d'énergie noire avec uneprécision dix fois meilleure que les contraintes actuelles. Quatre des différentes sondes observationnellessensibles au contenu énergétique de l'Univers seront accessible à LSST : les supernovaede type Ia, les amas de galaxies, les lentilles gravitationnelles et les oscillations acoustiques debaryons (BAO). La combinaison de ces sondes devrait permettre de différencier les différentsmodèles théoriques décrivant l'énergie noire. Cette thèse s'inscrit dans le cadre du projet LSSTet présente à la fois un aspect instrumental et une étude phénoménologique. Dans un premiertemps, le travail concernant le développement d'un banc d'étalonnage optique pour la camérasera présenté. Les mesures alors effectuées ont conduit à l'établissement du design canal de lasource de lumière. Le banc d'étalonnage va ainsi permettre une mesure précise de la réponsedu plan focal de la caméra dans les longueurs d'ondes associées aux six filtres de LSST. Nousprésenterons ensuite une chaine d'analyse complète dont l'objectif est d'estimer la précision aveclaquelle il sera possible de mesurer l'échelle caractéristiques des BAOs à partir des données deLSST. Dans ce but un catalogue de galaxies a été simulé à partir d'une cosmologie CDM.L'utilisation d'une méthode de template tting, combinée à différents tests statistiques a permisl'obtention de redshifts photométriques (photo-z) de bonne qualité, respectant les spécificationsLSST. Une étude portant sur l'impact de la transmission des filtres a permis l'optimisation deleur bande-passante et a montré l'importance de leur étalonnage. Enfin l'échelle caractéristiquedes BAO a été estimé en tenant compte des erreurs photo-z, validant l'ensemble de la chaine desimulation<br>The LSST telescope (Large Synoptic Survey Telescope) is part of the new generation of opticalinstruments whose aim is to achieve a complete map of the Universe. With its wide and largefield of view, it will observed billions of galaxies, in six optical photometric bands. allowing thestudy of many scientifcc subjects. In particular, LSST data will accurately measure Dark Energyparameters through four distinct probes: supernovae, week lensing, clusters and Baryon AcousticOscillations (BAO). The combination of those different probes should allowed the discriminationbetween theoretical models describing the dark energy. This thesis is part of the development ofthe LSST project and presents both an instrumental and a phenomenological study. First, thework concerning the development of the optical calibration bench for LSST's camera is presented.The measurements then performed led to the establishment of the light source final design.The calibration bench will thus allow measurement of the camera focal plan response withinthe six wavelength corresponding to LSST filters. We then present a complete analysis chainwhose objective is to estimate the accuracy with which the characteristics BAOs scale should bemeasured considering LSST simulated data. With this aim,a galaxy catalog were simulate froma CDM cosmology. An enhanced template setting method has been developed, combined withstatistical tests, it allowed a significant improvement of the photo-z reconstruction quality up,in agreement with LSST requirements. A study of the impact of the filterslters transmission curvesallowed the optimization of their bandwidth and showed the importance of their calibration.Finally the BAOs scale was estimated taking into account the photo-z errors, compelling thewhole simulation
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Perry, Michael James Samuel. "High spatial resolution retrieval of LST and LSE for the urban environment." Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/40022.
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Understanding the changing and complex urban thermal environment is key to addressing the health and sustainability of the cities in which more than half of the world’s population live. The monitoring and assessment of the thermal environment requires spatial resolution that so far has precluded air temperatures from being a viable parameter in most cities. Land surface temperatures (LSTs) offer the ability through satellite remote sensing to investigate the urban environment in a robust and consistent manner. Additionally land surface emissivity (LSE) is required to enable accurate LST estimation and characterise broad-scale thermal infra-red properties of materials. In this thesis, the first optimal estimation of simultaneous LST and LSE data optimised to be robust for urban areas with highly complex surfaces is presented. It uses the thermal channels of the ASTER instrument with a spatial resolution of 90 m. In simulations the algorithm retrieved LST to 1 K or better, and LSEs to within 0.01. The simulation uncertainties retrieved are better than 1 K in LST and 0.015-0.017 for LSE. This marks the first usage of an inverse method with ASTER data. Verification of the LSE for a non-urban scene (Algodones) was undertaken, through inter-comparison with the TES method. Results agreed well with both TES and the validation site in channel 12 and with very low retrieval radiance residuals. The algorithm was also used in three urban case studies. In each, this scheme was able to address key scientific issues, including urban green space and rapid urban expansion, using a combination of the LST and the LSE. The high accuracy of the retrieved LSE was able to distinguish characteristic LSE spectra and identify surface changes. These results show the retrieval of robust and scientifically meaningful LST and LSE data for the heterogeneous urban environment from ASTER, vital to urban studies.
Bücher zum Thema "LSWT"
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1962-, Rimal Rajiv N., and Orton Peter Z, eds. LSAT. 5th ed. Wiley Pub., 2001.
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H, Martinson Thomas, ed. LSAT supercourse. 4th ed. Prentice Hall, 1993.
Den vollen Inhalt der Quelle findenBuchteile zum Thema "LSWT"
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Gentsch, Jan, and Kira Splitt. "LSBT-Einrichtungen." In Handbuch Offene Kinder- und Jugendarbeit. Springer Fachmedien Wiesbaden, 2021. http://dx.doi.org/10.1007/978-3-658-22563-6_37.
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Shayler, David J., and David M. Harland. "LST becomes ST, becomes HST." In The Hubble Space Telescope. Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-2827-9_4.
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Kelava, Augustin, Karin Schermelleh-Engel, and Axel Mayer. "Latent-State-Trait-Theorie (LST-Theorie)." In Testtheorie und Fragebogenkonstruktion. Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/978-3-662-61532-4_26.
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Kelava, Augustin, and Karin Schermelleh-Engel. "Latent-State-Trait-Theorie (LST-Theorie)." In Springer-Lehrbuch. Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-71635-8_15.
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Fernández Barral, Alba. "Quality Control of LST Camera Subsystems." In Extreme Particle Acceleration in Microquasar Jets and Pulsar Wind Nebulae with the MAGIC Telescopes. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97538-2_10.
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Kelava, Augustin, and Karin Schermelleh-Engel. "Latent-State-Trait-Theorie (LST-Theorie)." In Springer-Lehrbuch. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-20072-4_15.
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Arekhi, Maliheh. "Investigating Land Surface Temperature (LST) Change Using the LST Change Detection Technique (Gomishan District, Iran)." In Advances in Remote Sensing and Geo Informatics Applications. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01440-7_32.
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Müller, Frerk, Peter Hoffmann, Melina Frenken, Andreas Hein, and Otthein Herzog. "LsW: Networked Home Automation in Living Environments." In Ambient Assisted Living. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37988-8_2.
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Sun, Donglian, and Yunyue Yu. "Land Surface Temperature (LST) Retrieval from GOES Satellite Observations." In Satellite-based Applications on Climate Change. Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-5872-8_19.
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Wang, Yun, Z. Y. Xu, Y. H. Fu, and Lan Cai. "Investigation into LST and its Novel Application in Mould." In Advanced Materials Research. Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-461-8.189.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "LSWT"
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Brown, Clifford A., and Nicholas A. Schifer. "Low Frequency Noise Contamination in Fan Model Testing." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50850.
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Aircraft engine noise research and development depends on the ability to study and predict the noise created by each engine component in isolation. The presence of a downstream pylon for a model fan test, however, may result in noise contamination through pylon interactions with the free stream and model exhaust airflows. Additionally, there is the problem of separating the fan and jet noise components generated by the model fan. A methodology was therefore developed to improve the data quality for the 9 × 15 Low Speed Wind Tunnel (LSWT) at the NASA Glenn Research Center that identifies three noise sources: fan noise, jet noise, and rig noise. The jet noise and rig noise were then measured by mounting a scale model of the 9 × 15 LSWT model fan installation in a jet rig to simulate everything except the rotating machinery and in duct components of fan noise. The data showed that the spectra measured in the LSWT has a strong rig noise component at frequencies as high as 3 kHz depending on the fan and airflow fan exit velocity. The jet noise was determined to be significantly lower than the rig noise (i.e. noise generated by flow interaction with the downstream support pylon). A mathematical model for the rig noise was then developed using a multi-dimensional least squares fit to the rig noise data. This allows the rig noise to be subtracted or removed, depending on the amplitude of the rig noise relative to the fan noise, at any given frequency, observer angle, or nozzle pressure ratio. The impact of isolating the fan noise with this method on spectra, overall power level (OAPWL), and Effective Perceived Noise Level (EPNL) is studied.
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Marks, Christopher, Rolf Sondergaard, Mitch Wolff, and Rich Anthony. "Experimental Comparison of DBD Plasma Acuators for Low Reynolds Number Separation Control." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45397.
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This paper presents experimental work comparing several Dielectric Barrier Discharge (DBD) plasma actuator configurations for low Reynolds number separation control. Actuators studied here are being investigated for use in a closed loop separation control system. The plasma actuators were fabricated in the U. S. Air Force Research Laboratory Propulsion Directorate’s thin film laboratory and applied to a low Reynolds number airfoil that exhibits similar suction surface behavior to those observed on Low Pressure (LP) Turbine blades. In addition to typical asymmetric arrangements producing downstream jets, one electrode configurations was designed to produce an array of off axis jets, and one produced a spanwise array of linear vertical jets in order to generate vorticity and improved boundary layer to freestream mixing. The actuators were installed on an airfoil and their performance compared by flow visualization, surface stress sensitive film (S3F), and drag measurements. The experimental data provides a clear picture of the potential utility of each design. Experiments were carried out at four Reynolds numbers, 1.4×105, 1.0 × 105, 6.0 × 104, and 5.0 × 104 at a −1.54° angle of attack. Data was taken at the AFRL Propulsion Directorate’s Low Speed Wind Tunnel (LSWT) facility.
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Davison, Warren B., Mario H. Rascon, Brian Cuerden, et al. "LSST structural design." In SPIE Astronomical Telescopes + Instrumentation, edited by Joseph Antebi and Dietrich Lemke. SPIE, 2004. http://dx.doi.org/10.1117/12.552233.
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Schumacher, Germán, Michael Warner, and Victor Krabbendam. "LSST control system." In SPIE Astronomical Telescopes + Instrumentation, edited by Hilton Lewis and Alan Bridger. SPIE, 2006. http://dx.doi.org/10.1117/12.671284.
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Olivier, Scot S., Lynn Seppala, Kirk Gilmore, Layton Hale, and Wayne Whistler. "LSST camera optics." In SPIE Astronomical Telescopes + Instrumentation, edited by Eli Atad-Ettedgui, Joseph Antebi, and Dietrich Lemke. SPIE, 2006. http://dx.doi.org/10.1117/12.673235.
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Sebag, Jacques, Victor Krabbendam, Chuck Claver, et al. "LSST site evaluation." In SPIE Astronomical Telescopes + Instrumentation, edited by Larry M. Stepp. SPIE, 2006. http://dx.doi.org/10.1117/12.670615.
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Starr, Barry M., Charles F. Claver, Sidney Wolff, et al. "LSST Instrument Concept." In Astronomical Telescopes and Instrumentation, edited by J. Anthony Tyson and Sidney Wolff. SPIE, 2002. http://dx.doi.org/10.1117/12.457331.
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Shi, Hongfu, Yingxian Liu, Yifan He, and Wankun Xu. "The Simulation and Pilot Application of Low Salinity Water Flooding for Offshore Low Permeability Reservoir." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21257-ms.
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Abstract The use of LSWF (Low Salinity Water Flooding) is becoming more prevalent in recent years which can both improve the recovery factor and reduce the cost compared to other EOR (enhanced oil recovery) technics. This is especially important for the offshore oilfield development at present. Moreover, good quality of injected water is more applicable to low permeability sand which is characterized as smaller pore-throat radius and is easier damaged. Therefore, LSWF technology is proposed to address the above production problem while reduce the investment of equipment upgrade. In this paper, we presented the optimization and implementation of LSWF for offshore low permeability reservoir. Firstly, we provided a critical review of LSWF included the main mechanisms, laboratory test and field effect. Secondly, we designed and conducted several laboratory core flood tests. Thirdly, a lot of synthetic models were established to simulate the effects of LSWF and to optimize the field program. Finally, the production performance of the pilot wells was discussed. After LSWF, the water injection well presents the phenomenon of "scissors" - the injection pressure drops significantly below the safety pressure while the injection volume increases. Moreover, the decline of pilot well groups decreased by 20% ~ 26% compared with non-water flooded. The estimated recovery factor increased by 12%, which is consistent with other field tests worldwide. In summary, LSWF is a feasible, neconomic and efficient method for offshore low permeability reservoir production.
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Adila, Ahmed S., Emad W. Al-Shalabi, and Waleed Alameri. "A New Insight into Hybrid Surfactant and Low Salinity/Engineered Water Injections in Carbonates Through Geochemical Modeling." In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31128-ms.
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Abstract Low salinity/engineered water injections (LSWI/EWI) have gained popularity as effective techniques for enhancing oil recovery. Surfactant flooding is also a well-established and commercially-available technique in the oil and gas industry. In this paper, a numerical 2D simulation model was developed to investigate the effect of hybrid surfactant-LSWI/EWI on oil recovery from carbonate cores under harsh conditions. The developed simulation model was validated by history-matching recently conducted surfactant corefloods in the secondary mode of injection. Oil recovery, pressure drop, and surfactant concentration data were utilized. The surfactant flooding model was then coupled with a geochemical model that captures different reactions during LSWI/EWI. The geochemical reactions considered include aqueous, dissolution/precipitation, and ion-exchange reactions. Different simulation scenarios were considered and compared including waterflooding, surfactant flooding, engineered water injection, hybrid surfactant-EWI, and hybrid surfactant-LSWI. Additionally, sensitivity analysis was performed on the hybrid surfactant-EWI process through capturing changes in surfactant injected concentration and adsorption. For the case of LSWI/EWI, wettability alteration was considered as the main mechanism underlying incremental oil recovery. However, both wettability alteration and interfacial tension reduction mechanisms were considered for surfactant flooding depending on the type of surfactant used. The results showed that the hybrid surfactant-EWI altered the wettability and achieved higher oil recovery than that of surfactant-LSWI and other techniques. This highlights the importance of selecting the right combinations of potential ions for a certain reservoir to maximize oil recovery rather than a simple water dilution. The results also highlight the importance of surfactant adsorption and surfactant concentration for the hybrid surfactant-EWI technique. This work provides insights into the application of hybrid surfactant-LSWI/EWI on oil recovery especially in carbonates. The novelty of this work is further expanded through comparing surfactant-LSWI with surfactant-EWI and understanding the controlling parameters of surfactant-EWI through sensitivity analysis.
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Gressler, William J., Douglas R. Neill, John Bagnasco, et al. "LSST secondary mirror assembly." In Ground-based and Airborne Telescopes VII, edited by Roberto Gilmozzi, Heather K. Marshall, and Jason Spyromilio. SPIE, 2018. http://dx.doi.org/10.1117/12.2311316.
Der volle Inhalt der QuelleBerichte der Organisationen zum Thema "LSWT"
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Wolfe, Justin E. LSST Painting Risk Evaluation Memo. Office of Scientific and Technical Information (OSTI), 2016. http://dx.doi.org/10.2172/1342020.
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Abell, Paul, and et al. LSST Science Book, Version 2.0. Office of Scientific and Technical Information (OSTI), 2009. http://dx.doi.org/10.2172/1156415.
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Stout, Tiarra Johannas. LSST Charge-Coupled Device Calibration. Office of Scientific and Technical Information (OSTI), 2011. http://dx.doi.org/10.2172/1017213.
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Fermi Research Alliance, LLC. LSST Undergraduate Internships at Fermilab. Office of Scientific and Technical Information (OSTI), 2021. http://dx.doi.org/10.2172/1775511.
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Asztalos, S. LSST Dark Energy Science Final Report. Office of Scientific and Technical Information (OSTI), 2007. http://dx.doi.org/10.2172/902379.
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Richards, Gordon, Christina Peters, Bee Martin, et al. Leveraging Differential Chromatic Refraction in LSST. LSST AGN Science Collaboration, 2018. http://dx.doi.org/10.17918/k90k-ey97.
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Nikolaev, S., G. Abdulla, and R. Matzke. Evaluation of Potential LSST Spatial Indexing Strategies. Office of Scientific and Technical Information (OSTI), 2006. http://dx.doi.org/10.2172/895409.
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Abdulla, G., J. Brase, K. Cook, and M. Miller. LSST data pipeline prototyping plans and strategy. Office of Scientific and Technical Information (OSTI), 2004. http://dx.doi.org/10.2172/15009840.
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Nikolaev, S., M. Huber, K. Cook, G. Abdulla, and J. Brase. Conceptual Design of a Prototype LSST Database. Office of Scientific and Technical Information (OSTI), 2004. http://dx.doi.org/10.2172/875675.
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Dawson, W. A., and M. D. Schneider. Complementarity of LSST and WFIRST: Regarding Object Blending. Office of Scientific and Technical Information (OSTI), 2014. http://dx.doi.org/10.2172/1122197.
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