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Paulo G Coelho - One of the best experts on this subject based on the ideXlab platform.
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thermal mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystal core veneer all ceramic layered crown Design
European Journal of Oral Sciences, 2010Co-Authors: Estevam A Bonfante, Brian T Rafferty, Ricardo Alexandre Zavanelli, Nelson R F A Silva, E D Rekow, Van P Thompson, Paulo G CoelhoAbstract:This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an Alternative core Design vs. a standard core Design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided Design (CAD) software and a tooth preparation was modeled. A crown was Designed using the space between the original tooth and the prepared tooth. The Alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both Designs under loading and when cooled from 900 degrees C to 25 degrees C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the Alternative Design compared with the standard Design. Significantly higher reliability was found for the Alternative core. Regardless of the Alternative configuration, thermal and mechanical computer simulations showed stress in the Alternative core Design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the Alternative Design under fatigue.
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thermal mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystal core veneer all ceramic layered crown Design
European Journal of Oral Sciences, 2010Co-Authors: Estevam A Bonfante, Brian T Rafferty, Ricardo Alexandre Zavanelli, Nelson R F A Silva, E D Rekow, Van P Thompson, Paulo G CoelhoAbstract:Bonfante EA, Rafferty B, Zavanelli RA, Silva NRFA, Rekow ED, Thompson VP, Coelho PG. Thermal/mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystalcore-veneer all-ceramic layered crown Design. Eur J Oral Sci 2010; 118: 202–209. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an Alternative core Design vs. a standard core Design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided Design (CAD) software and a tooth preparation was modeled. A crown was Designed using the space between the original tooth and the prepared tooth. The Alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both Designs under loading and when cooled from 900°C to 25°C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the Alternative Design compared with the standard Design. Significantly higher reliability was found for the Alternative core. Regardless of the Alternative configuration, thermal and mechanical computer simulations showed stress in the Alternative core Design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the Alternative Design under fatigue.
Alexandros A Taflanidis - One of the best experts on this subject based on the ideXlab platform.
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performance assessment and optimization of fluid viscous dampers through life cycle cost criteria and comparison to Alternative Design approaches
Bulletin of Earthquake Engineering, 2015Co-Authors: Ioannis Gidaris, Alexandros A TaflanidisAbstract:The performance assessment and optimal Design of fluid viscous dampers through life-cycle cost criteria is discussed in this paper. A probabilistic, simulation-based framework is described for estimating the life-cycle cost and a stochastic search approach is developed to support an efficient optimization under different Design scenarios (corresponding to different seismicity characteristics). Earthquake losses are estimated using an assembly-based vulnerability approach utilizing the nonlinear dynamic response of the structure whereas a point source stochastic ground motion model, extended here to address near-fault pulse effects, is adopted to describe the seismic hazard. Stochastic simulation is utilized for estimation of all the necessary probabilistic quantities, and for reducing the computational burden a surrogate modeling methodology is integrated within the framework. Two simplified Design approaches are also examined, the first considering the optimization of the stationary response, utilizing statistical linearization to address nonlinear damper characteristics, and the second adopting an equivalent lateral force procedure that defines a targeted damping ratio for the structure. These Designs are compared against the optimal life-cycle cost one, whereas a compatible comparison is facilitated by establishing an appropriate connection between the seismic input required for the simplified Designs and the probabilistic earthquake hazard model. As an illustrative example, the retrofitting of a three-story reinforced concrete office building with nonlinear dampers is considered.
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performance assessment and optimization of fluid viscous dampers through life cycle cost criteria and comparison to Alternative Design approaches
Bulletin of Earthquake Engineering, 2015Co-Authors: Ioannis Gidaris, Alexandros A TaflanidisAbstract:The performance assessment and optimal Design of fluid viscous dampers through life-cycle cost criteria is discussed in this paper. A probabilistic, simulation-based framework is described for estimating the life-cycle cost and a stochastic search approach is developed to support an efficient optimization under different Design scenarios (corresponding to different seismicity characteristics). Earthquake losses are estimated using an assembly-based vulnerability approach utilizing the nonlinear dynamic response of the structure whereas a point source stochastic ground motion model, extended here to address near-fault pulse effects, is adopted to describe the seismic hazard. Stochastic simulation is utilized for estimation of all the necessary probabilistic quantities, and for reducing the computational burden a surrogate modeling methodology is integrated within the framework. Two simplified Design approaches are also examined, the first considering the optimization of the stationary response, utilizing statistical linearization to address nonlinear damper characteristics, and the second adopting an equivalent lateral force procedure that defines a targeted damping ratio for the structure. These Designs are compared against the optimal life-cycle cost one, whereas a compatible comparison is facilitated by establishing an appropriate connection between the seismic input required for the simplified Designs and the probabilistic earthquake hazard model. As an illustrative example, the retrofitting of a three-story reinforced concrete office building with nonlinear dampers is considered.
Bilík Ondřej - One of the best experts on this subject based on the ideXlab platform.
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Alternative Design of structure of railway bridge in km 19,459 railway track Děčín – Oldřichov over the highway D8
Vysoké učení technické v Brně. Fakulta stavební, 2013Co-Authors: Bilík OndřejAbstract:This master thesis contents Alternative Design of three spans single-railed steel bridge and its main bearing structures. The bridge is located in km 19,459 on the track Děčín - Oldřichov. Crossing barrier is highway D8. The span is 28,38 m + 41,28 m + 28,38 m. The main bearing structure consists of solid steel beams with variable height of 2,3 m ~ 3,8 m, which are in the axial distance of 6 meters and reinforced with lengthwise and transverse stiffeners. The lower bridge deck with a continuous ballast bed consists of reinforced concrete bath, which is coupled with steel cross beams. All elements of the structure are made out of steel S 355. For Design of the following standards have been used: ČSN EN 1991-2, ČSN EN 1993, ČSN EN 1994 – 2
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Alternative Design of structure of railway bridge in km 19,459 railway track Děčín – Oldřichov over the highway D8
Vysoké učení technické v Brně. Fakulta stavební, 2013Co-Authors: Bilík OndřejAbstract:Předmětem diplomové práce je alternativní návrh nosné konstrukce jednokolejného ocelového železničního mostu o třech polích. Most se nachází v km 19,459 na trati Děčín - Oldřichov. Překračovanou překážkou je dálnice D8. Rozpětí polí je 28,38m + 41,28m + 28,38m. Hlavní nosnou konstrukci tvoří plnostěnné ocelové nosníky proměnné výšky 2,3m ~ 3,8m, které jsou v osové vzdálenosti 6 metrů a jsou vyztuženy podélnými a příčnými výztuhami. Dolní mostovka, která nese průběžné kolejové lože, je tvořena železobetonovou vanou spřaženou s ocelovými příčníky. Všechny nosné prvky konstrukce jsou vyrobeny z oceli S 355. Při zpracování byly použity zejména normy ČSN EN 1991 – 2 Zatížení konstrukcí – Zatížení mostů dopravou, navrhování a posuzování konstrukce je podle ČSN EN 1993 Navrhování ocelových konstrukcí, ČSN EN 1994 - 2 Navrhování spřažených ocelobetonových konstrukcí – obecná pravidla pro mosty.This master thesis contents Alternative Design of three spans single-railed steel bridge and its main bearing structures. The bridge is located in km 19,459 on the track Děčín - Oldřichov. Crossing barrier is highway D8. The span is 28,38 m + 41,28 m + 28,38 m. The main bearing structure consists of solid steel beams with variable height of 2,3 m ~ 3,8 m, which are in the axial distance of 6 meters and reinforced with lengthwise and transverse stiffeners. The lower bridge deck with a continuous ballast bed consists of reinforced concrete bath, which is coupled with steel cross beams. All elements of the structure are made out of steel S 355. For Design of the following standards have been used: ČSN EN 1991-2, ČSN EN 1993, ČSN EN 1994 – 2.
Estevam A Bonfante - One of the best experts on this subject based on the ideXlab platform.
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thermal mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystal core veneer all ceramic layered crown Design
European Journal of Oral Sciences, 2010Co-Authors: Estevam A Bonfante, Brian T Rafferty, Ricardo Alexandre Zavanelli, Nelson R F A Silva, E D Rekow, Van P Thompson, Paulo G CoelhoAbstract:This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an Alternative core Design vs. a standard core Design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided Design (CAD) software and a tooth preparation was modeled. A crown was Designed using the space between the original tooth and the prepared tooth. The Alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both Designs under loading and when cooled from 900 degrees C to 25 degrees C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the Alternative Design compared with the standard Design. Significantly higher reliability was found for the Alternative core. Regardless of the Alternative configuration, thermal and mechanical computer simulations showed stress in the Alternative core Design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the Alternative Design under fatigue.
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thermal mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystal core veneer all ceramic layered crown Design
European Journal of Oral Sciences, 2010Co-Authors: Estevam A Bonfante, Brian T Rafferty, Ricardo Alexandre Zavanelli, Nelson R F A Silva, E D Rekow, Van P Thompson, Paulo G CoelhoAbstract:Bonfante EA, Rafferty B, Zavanelli RA, Silva NRFA, Rekow ED, Thompson VP, Coelho PG. Thermal/mechanical simulation and laboratory fatigue testing of an Alternative yttria tetragonal zirconia polycrystalcore-veneer all-ceramic layered crown Design. Eur J Oral Sci 2010; 118: 202–209. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an Alternative core Design vs. a standard core Design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided Design (CAD) software and a tooth preparation was modeled. A crown was Designed using the space between the original tooth and the prepared tooth. The Alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both Designs under loading and when cooled from 900°C to 25°C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the Alternative Design compared with the standard Design. Significantly higher reliability was found for the Alternative core. Regardless of the Alternative configuration, thermal and mechanical computer simulations showed stress in the Alternative core Design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the Alternative Design under fatigue.
Yunus Cerci - One of the best experts on this subject based on the ideXlab platform.
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exergy analysis of a reverse osmosis desalination plant in california
Desalination, 2002Co-Authors: Yunus CerciAbstract:Abstract The exergy analysis of a 7250 m3/d reverse osmosis (RO) desalination plant in California was conducted by using actual plant operation data, and an Alternative Design was investigated to improve its performance. The RO plant is described in detail, and the exergies across the major components of the plant are calculated and illustrated using exergy flow diagrams in an attempt to assess the exergy destruction distribution. The primary locations of exergy destruction were the membrane modules in which the saline water is separated into the brine and the permeate, and the throttling valves where the pressure of liquid is reduced, pressure drops through various process components, and the mixing chamber where the permeate and blend are mixed. The largest exergy destruction occurred in the membrane modules, and this amounted to 74.07% of the total exergy input. The smallest exergy destruction occurred in the mixing chamber. The mixing accounted for 0.67% of the total exergy input and presents a relatively small fraction. The second law of efficiency of the plant was calculated to be 4.3%, which seems to be low. The analysis of the Alternative Design was based on the exergy analysis. It is shown that the second law of efficiency can be increased to 4.9% by introducing a pressure exchanger with two throttling valves on the brine stream, and this saved 19.8 kW electricity by reducing the pumping power of the incoming saline water.