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B Akalin - One of the best experts on this subject based on the ideXlab platform.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
Matthew Rodell - One of the best experts on this subject based on the ideXlab platform.
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rivers and floodplains as key components of global terrestrial Water Storage variability
Geophysical Research Letters, 2017Co-Authors: Sujay V Kumar, Augusto Getirana, Manuela Girotto, Matthew RodellAbstract:This study quantifies the contribution of rivers and floodplains to terrestrial Water Storage (TWS) variability. We use state-of-the-art models to simulate land surface processes and river dynamics and to separate TWS into its main components. Based on a proposed impact index, we show that surface Water Storage (SWS) contributes 8% of TWS variability globally, but that contribution differs widely among climate zones. Changes in SWS are a principal component of TWS variability in the tropics, where major rivers flow over arid regions and at high latitudes. SWS accounts for ~22–27% of TWS variability in both the Amazon and Nile Basins. Changes in SWS are negligible in the Western U.S., Northern Africa, Middle East, and central Asia. Based on comparisons with Gravity Recovery and Climate Experiment-based TWS, we conclude that accounting for SWS improves simulated TWS in most of South America, Africa, and Southern Asia, confirming that SWS is a key component of TWS variability.
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a grace based Water Storage deficit approach for hydrological drought characterization
Geophysical Research Letters, 2014Co-Authors: Alys C Thomas, James Famiglietti, John T Reager, Matthew RodellAbstract:We present a quantitative approach for measuring hydrological drought occurrence and severity based on terrestrial Water Storage observations from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE measurements are applied by calculating the magnitude of the deviation of regional, monthly terrestrial Water Storage anomalies from the time series' monthly climatology, where negative deviations represent Storage deficits. Monthly deficits explicitly quantify the volume of Water required to return to normal Water Storage conditions. We combine Storage deficits with event duration to calculate drought severity. Drought databases are referenced to identify meteorological drought events in the Amazon and Zambezi River basins and the southeastern United States and Texas regions. This Storage deficit method clearly identifies hydrological drought onset, end, and duration; quantifies instantaneous severity and peak drought magnitude; and compares well with the meteorological drought databases. It also reveals information about the hydrological effects of meteorological drought on regional Water Storage. Key Point GRACE-based drought severity using Water Storage rather than just precipitation explicitly quantifies the volume of Water needed to return to normal conditions and identifies hydrological drought onset, peak magnitude, duration, and severity ©2014. American Geophysical Union. All Rights Reserved.
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impact of Water withdrawals from groundWater and surface Water on continental Water Storage variations
Journal of Geodynamics, 2012Co-Authors: Petra Doll, Matthew Rodell, H Hoffmanndobrev, Felix T Portmann, Stefan Siebert, Annette Eicker, Gil Strassberg, Bridget R ScanlonAbstract:a b s t r a c t Humans have strongly impacted the global Water cycle, not only Water flows but also Water Storage. We have performed a first global-scale analysis of the impact of Water withdrawals on Water Storage variations, using the global Water resources and use model WaterGAP. This required estimation of frac- tions of total Water withdrawals from groundWater, considering five Water use sectors. According to our assessment, the source of 35% of the Water withdrawn worldwide (4300 km3/year during 1998-2002) is groundWater. GroundWater contributes 42%, 36% and 27% of Water used for irrigation, households and manufacturing, respectively, while we assume that only surface Water is used for livestock and for cooling of thermal power plants. Consumptive Water use was 1400 km 3 /year during 1998-2002. It is the sum of
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attenuation effect on seasonal basin scale Water Storage changes from grace time variable gravity
Journal of Geodesy, 2007Co-Authors: Jianli Chen, James Famiglietti, Clark R Wilson, Matthew RodellAbstract:In order to effectively recover surface mass or geoid height changes from the gravity recovery and climate experiment (GRACE) time-variable gravity models, spatial smoothing is required to minimize errors from noise. Spatial smoothing, such as Gaussian smoothing, not only reduces the noise but also attenuates the real signals. Here we investigate possible amplitude attenuations and phase changes of seasonal Water Storage variations in four drainage basins (Amazon, Mississippi, Ganges and Zambezi) using an advanced global land data assimilation system. It appears that Gaussian smoothing significantly affects GRACE-estimated basin-scale seasonal Water Storage changes, e.g., in the case of 800 km smoothing, annual amplitudes are reduced by about 25-40%, while annual phases are shifted by up to 10°. With these effects restored, GRACE-estimated Water Storage changes are consistently larger than model estimates, indicating that the land surface model appears to underestimate terrestrial Water Storage change. Our analysis based on simulation suggests that normalized attenuation effects (from Gaussian smoothing) on seasonal Water Storage change are relatively insensitive to the magnitude of the true signal. This study provides a numerical approach that can be used to restore seasonal Water Storage change in the basins from spatially smoothed GRACE data. © Springer-Verlag 2006.
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Detectability of variations in continental Water Storage from satellite observations of the time dependent gravity field
Water Resources Research, 1999Co-Authors: Matthew Rodell, James FamigliettiAbstract:Continental Water Storage is a key variable in the Earth system that has never been adequately monitored globally. Since variations in Water Storage on land affect the time dependent component of Earth's gravity field, the NASA Gravity Recovery and Climate Experiment (GRACE) satellite mission, which will accurately map the gravity field at 2-4 week intervals, may soon provide global data on temporal changes in continental Water Storage. This study characterizes Water Storage changes in 20 drainage basins ranging in size from 130,000 to 5,782,000 km(2) and uses estimates of uncertainty in the GRACE technique to determine in which basins Water Storage changes may be detectable by GRACE and how this detectability may vary in space and time. Results indicate that GRACE will likely detect changes in Water Storage in most of the basins on monthly or longer time steps and that instrument errors, atmospheric modeling errors, and the magnitude of the variations themselves will be the primary controls on the relative accuracy of the GRACE-derived estimates.
A Arikan - One of the best experts on this subject based on the ideXlab platform.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
James Famiglietti - One of the best experts on this subject based on the ideXlab platform.
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a grace based Water Storage deficit approach for hydrological drought characterization
Geophysical Research Letters, 2014Co-Authors: Alys C Thomas, James Famiglietti, John T Reager, Matthew RodellAbstract:We present a quantitative approach for measuring hydrological drought occurrence and severity based on terrestrial Water Storage observations from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE measurements are applied by calculating the magnitude of the deviation of regional, monthly terrestrial Water Storage anomalies from the time series' monthly climatology, where negative deviations represent Storage deficits. Monthly deficits explicitly quantify the volume of Water required to return to normal Water Storage conditions. We combine Storage deficits with event duration to calculate drought severity. Drought databases are referenced to identify meteorological drought events in the Amazon and Zambezi River basins and the southeastern United States and Texas regions. This Storage deficit method clearly identifies hydrological drought onset, end, and duration; quantifies instantaneous severity and peak drought magnitude; and compares well with the meteorological drought databases. It also reveals information about the hydrological effects of meteorological drought on regional Water Storage. Key Point GRACE-based drought severity using Water Storage rather than just precipitation explicitly quantifies the volume of Water needed to return to normal conditions and identifies hydrological drought onset, peak magnitude, duration, and severity ©2014. American Geophysical Union. All Rights Reserved.
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global terrestrial Water Storage capacity and flood potential using grace
Geophysical Research Letters, 2009Co-Authors: John T Reager, James FamigliettiAbstract:Terrestrial Water Storage anomaly from the Gravity Recovery and Climate Experiment (GRACE) and precipitation observations from the Global Precipitation Climatology Project (GPCP) are applied at the regional scale to show the usefulness of a remotely sensed, Storage-based flood potential method. Over the GRACE record length, instances of repeated maxima in Water Storage anomaly that fall short of variable maxima in cumulative precipitation suggest an effective Storage capacity for a given region, beyond which additional precipitation must be met by marked increases in runoff or evaporation. These saturation periods indicate the possible transition to a flood-prone situation. To investigate spatially and temporally variable Storage overflow, a monthly Storage deficit variable is created and a global map of effective Storage capacity is presented for possible use in land surface models. To highlight a flood-potential application, we design a monthly global flood index and compare with Dartmouth Flood Observatory flood maps.
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attenuation effect on seasonal basin scale Water Storage changes from grace time variable gravity
Journal of Geodesy, 2007Co-Authors: Jianli Chen, James Famiglietti, Clark R Wilson, Matthew RodellAbstract:In order to effectively recover surface mass or geoid height changes from the gravity recovery and climate experiment (GRACE) time-variable gravity models, spatial smoothing is required to minimize errors from noise. Spatial smoothing, such as Gaussian smoothing, not only reduces the noise but also attenuates the real signals. Here we investigate possible amplitude attenuations and phase changes of seasonal Water Storage variations in four drainage basins (Amazon, Mississippi, Ganges and Zambezi) using an advanced global land data assimilation system. It appears that Gaussian smoothing significantly affects GRACE-estimated basin-scale seasonal Water Storage changes, e.g., in the case of 800 km smoothing, annual amplitudes are reduced by about 25-40%, while annual phases are shifted by up to 10°. With these effects restored, GRACE-estimated Water Storage changes are consistently larger than model estimates, indicating that the land surface model appears to underestimate terrestrial Water Storage change. Our analysis based on simulation suggests that normalized attenuation effects (from Gaussian smoothing) on seasonal Water Storage change are relatively insensitive to the magnitude of the true signal. This study provides a numerical approach that can be used to restore seasonal Water Storage change in the basins from spatially smoothed GRACE data. © Springer-Verlag 2006.
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Detectability of variations in continental Water Storage from satellite observations of the time dependent gravity field
Water Resources Research, 1999Co-Authors: Matthew Rodell, James FamigliettiAbstract:Continental Water Storage is a key variable in the Earth system that has never been adequately monitored globally. Since variations in Water Storage on land affect the time dependent component of Earth's gravity field, the NASA Gravity Recovery and Climate Experiment (GRACE) satellite mission, which will accurately map the gravity field at 2-4 week intervals, may soon provide global data on temporal changes in continental Water Storage. This study characterizes Water Storage changes in 20 drainage basins ranging in size from 130,000 to 5,782,000 km(2) and uses estimates of uncertainty in the GRACE technique to determine in which basins Water Storage changes may be detectable by GRACE and how this detectability may vary in space and time. Results indicate that GRACE will likely detect changes in Water Storage in most of the basins on monthly or longer time steps and that instrument errors, atmospheric modeling errors, and the magnitude of the variations themselves will be the primary controls on the relative accuracy of the GRACE-derived estimates.
T Arda - One of the best experts on this subject based on the ideXlab platform.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
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effect of 180 days of Water Storage on the transverse strength of acetal resin denture base material
Journal of Prosthodontics, 2010Co-Authors: A Arikan, T Arda, Yasemin Kulak Ozkan, B AkalinAbstract:Purpose: Acetal resin has been used as an alternative denture base and clasp material since 1986. The manufacturers claim that acetal resin has superior physical properties when compared to conventional denture base acrylic resins. Limited information is available about transverse strengths of acetal resin. The purpose of this investigation was to compare transverse strengths of pink and white acetal resins to transverse strengths of conventional heat-polymerized polymethylmethacrylate (PMMA) resin in increasing durations of Water Storage. Materials and Methods: A transverse strength test was performed in accordance with International Standards Organization (ISO) specification No 1567. Twenty 65 × 10 × 2.5 mm3 specimens of each resin were prepared; five specimens of each resin group were subjected to three-point bending test after 50 hours, 30 days, 60 days, and 180 days of Water Storage in distilled Water at 37°C. Experimental groups’ transverse strengths were compared by three-way ANOVA and Duncan's multiple range tests. Results: Transverse strength of PMMA denture base material was found to be in accordance with the requirements of ISO specification No 1567. Transverse strengths of white and pink acetal resin could not be calculated in this study, as white and pink acetal resin specimens did not break at the maximum applied force in the three-point bending test. Flexural strength of acetal resin was found to be within the ISO specification limits. As the Water Storage time increased, the deflection values of PMMA showed no significant difference (p > 0.05). Both the white and pink acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days (p < 0.05). Conclusion: The results of this study indicated that transverse strength values of PMMA were within the ISO specification limit. Water Storage time (50 hours, 30, 60, and 180 days) had no statistically significant effect on the transverse strength and deflection of PMMA. Acetal resin suffered from permanent deformation, but did not break in the three-point bending test. Acetal resin showed significant increase in deflection as the Water Storage time was increased from 50 hours to 180 days. All materials tested demonstrated deflection values in compliance with ISO specification No 1567.
