The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
David Ewins - One of the best experts on this subject based on the ideXlab platform.
-
multi axis vibration Testing of an aerodynamically excited structure
Journal of Vibration and Control, 2018Co-Authors: C Roberts, David EwinsAbstract:Missile vibration Testing has undergone significant advances in the past decade. This has been the result of improvements in signal processing and Test Specification development, but more recently due to the implementation of Multi-Input Multi-Output (MIMO) Testing. To date, much of the focus of MIMO Testing has been on either a twin-shaker, single-axis configuration or multi-axis Testing on a 3 or 6 Degree of Freedom (DOF) shaker system. There has been little attention to replication of the 3-dimensional operating deflection shapes that a missile system experiences during its carriage or operation.This paper presents a systematic approach to 3-axis vibration Testing, using current MIMO rectangular controller technology, and demonstrates through an experimental setup a near-3 fold improvement in matching the vibration response of the item under Test over the more traditional single axis SISO and MIMO Test methods.
Wasiuddin Nazimuddin - One of the best experts on this subject based on the ideXlab platform.
-
Development of a Standard Test Method for Characterization of Asphalt Modifiers and Aging-Related Degradation Using an Extensional Rheometer
LSU Digital Commons, 2018Co-Authors: Wasiuddin NazimuddinAbstract:Corresponding data set for Tran-SET Project No. 17BLSU01. Abstract of the final report is stated below for reference: An extensional deformation Test method using a Sentmanat Extensional Rheometer (SER) fixture inside a Dynamic Shear Rheometer (DSR) is developed in this study to investigate the degradation of the polymer due to aging and to investigate the effect of modifier type. A relationship between different percentages of modifier and ductility of the modified binder is also investigated. The sample geometrics used in this study are 1 mm 0.72 mm and 3 mm 0.72 mm. A total of one hundred and sixty-two samples were Tested. Three modifiers Styrene-Butadiene-Styrene (SBS), Polyphosphoric Acid (PPA) and latex were used. One PG 76-22, one PG 64-22 and one polymer-modified asphalt emulsion (PAME) were used. First peak elongation force, (F1) is the binders’ stiffness and Second peak elongation force, (F2) is the polymer characteristics. F2 is more visible comparatively at the higher temperature. In most cases, F2 reduces after Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV) aging. To normalize the stiffness effect of F1 on F2, in this study F2/F1 was used to analyze aging susceptibility of modifiers. All the Testing temperatures used in this study exhibited a reduction in F2/F1 due to RTFO aging and further reduction due to PAV aging. Therefore, through this study, it is recommended that this parameter can be used to determine aging susceptibility of polymer in a polymer-modified asphalt binder. F2 is only obtained from the SBS and latex modified binders and emulsions. Addition of PPA did not show any F2, making SBS the most effective modifier among SBS, PPA and latex. F2 has a linear correlation with the percent of the polymer in the PMAE, SBS modified PG 64-22, SBS and PPA modified PG 64-22 and latex modified PG 64-22 with R2 values equal to 0.9934, 0.9323, 0.9893 and 0.9535 respectively, indicating extensional deformation Test with SER very promising. Ductility analyses using final angular strain values indicate that modifiers increase ductility significantly while aging reduces ductility. Additional research is required for Testing ultra-violet (UV) aged sample, and a DSR-based SER Test Specification will be developed subsequently
-
Development of a Standard Test Method for Characterization of Asphalt Materials and Aging-Related Degradation using an Extensional Rheometer
LSU Digital Commons, 2018Co-Authors: Wasiuddin NazimuddinAbstract:An extensional deformation Test method using a Sentmanat Extensional Rheometer (SER) fixture inside a Dynamic Shear Rheometer (DSR) is developed in this study to investigate the degradation of the polymer due to aging and to investigate the effect of modifier type. A relationship between different percentages of modifier and ductility of the modified binder is also investigated. The sample geometrics used in this study are 1 mm x 0.72 mm and 3 mm x 0.72 mm. A total of one hundred and sixty-two samples were Tested. Three modifiers Styrene-Butadiene-Styrene (SBS), Polyphosphoric Acid (PPA) and latex were used. One PG 76-22, one PG 64-22 and one polymer-modified asphalt emulsion (PAME) were used. First peak elongation force, (F1) is the binders’ stiffness and Second peak elongation force, (F2) is the polymer characteristics. F2 is more visible comparatively at the higher temperature. In most cases, F2 reduces after Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV) aging. To normalize the stiffness effect of F1 on F2, in this study F2/F1 was used to analyze aging susceptibility of modifiers. All the Testing temperatures used in this study exhibited a reduction in F2/F1 due to RTFO aging and further reduction due to PAV aging. Therefore, through this study, it is recommended that this parameter can be used to determine aging susceptibility of polymer in a polymer-modified asphalt binder. F2 is only obtained from the SBS and latex modified binders and emulsions. Addition of PPA did not show any F2, making SBS the most effective modifier among SBS, PPA and latex. F2 has a linear correlation with the percent of the polymer in the PMAE, SBS modified PG 64-22, SBS and PPA modified PG 64-22 and latex modified PG 64-22 with R2 values equal to 0.9934, 0.9323, 0.9893 and 0.9535 respectively, indicating extensional deformation Test with SER very promising. Ductility analyses using final angular strain values indicate that modifiers increase ductility significantly while aging reduces ductility. Additional research is required for Testing ultra-violet (UV) aged sample, and a DSR-based SER Test Specification will be developed subsequentl
A F Crane - One of the best experts on this subject based on the ideXlab platform.
-
200 area treated effluent disposal facility operational Test Specification revision 2
Other Information: PBD: 9 Feb 1995, 1995Co-Authors: A F CraneAbstract:This document identifies the Test Specification and Test requirements for the 200 Area Treated Effluent Disposal Facility (200 Area TEDF) operational Testing activities. These operational Testing activities, when completed, demonstrate the functional, operational and design requirements of the 200 Area TEDF have been met. The technical requirements for operational Testing of the 200 Area TEDF are defined by the Test requirements presented in Appendix A. These Test requirements demonstrate the following: pump station No.1 and associated support equipment operate both automatically and manually; pump station No. 2 and associated support equipment operate both automatically and manually; water is transported through the collection and transfer lines to the disposal ponds with no detectable leakage; the disposal ponds accept flow from the transfer lines with all support equipment operating as designed; and the control systems operate and status the 200 Area TEDF including monitoring of appropriate generator discharge parameters.
-
200 area treated effluent disposal facility operational Test Specification
1995Co-Authors: A F CraneAbstract:This document identifies the Test Specification and Test requirements for the 200 Area Treated Effluent Disposal Facility (200 Area TEDF) operational Testing activities. These operational Testing activities, when completed, demonstrate the functional, operational and design requirements of the 200 Area TEDF have been met.
Lubinda F Walubita - One of the best experts on this subject based on the ideXlab platform.
-
the hamburg rutting Test effects of hma sample sitting time and Test temperature variation
Construction and Building Materials, 2016Co-Authors: Lubinda F Walubita, Abu N M Faruk, Jun Zhang, Sang Ick LeeAbstract:Abstract The Hamburg Wheel Tracking Test (HWTT) is a widely used routine laboratory Test with a proven history of successfully identifying and screening hot-mix asphalt (HMA) mixes that are prone to rutting and/or susceptible to moisture damage (stripping). Based on Texas Specification Tex-242-F, the HWTT is typically conducted at a single Test temperature of 50 °C (122 °F) with 12.5 mm rut depth as the standard HMA pass-fail screening criteria. However, with the record high summer temperatures of the recent years in Texas, several premature field rutting failures have occurred with some HMA mixes that had passed the HWTT screening criteria in the laboratory. This laboratory study was thus initiated to review and evaluate if the current Texas HWTT protocol and its associated Texas Test Specification (Tex-242-F) are simulative of the current summer field conditions for routine HMA mix-design and screening to optimize rutting resistance performance. Specifically, two key aspects were evaluated, namely the HMA sample sitting time and Test temperature. The corresponding laboratory Test results indicated that a maximum sample sitting time of five days should be consistently adapted, i.e., lab-molded samples should be Tested within five days of fabrication, particularly for HMA mix-design screening purposes. For HMA mixes to be used in high temperature/stress environments, the study findings suggested that higher (>50 °C), and/or multiple HWTT Test temperatures should be considered.
Sang Ick Lee - One of the best experts on this subject based on the ideXlab platform.
-
the hamburg rutting Test effects of hma sample sitting time and Test temperature variation
Construction and Building Materials, 2016Co-Authors: Lubinda F Walubita, Abu N M Faruk, Jun Zhang, Sang Ick LeeAbstract:Abstract The Hamburg Wheel Tracking Test (HWTT) is a widely used routine laboratory Test with a proven history of successfully identifying and screening hot-mix asphalt (HMA) mixes that are prone to rutting and/or susceptible to moisture damage (stripping). Based on Texas Specification Tex-242-F, the HWTT is typically conducted at a single Test temperature of 50 °C (122 °F) with 12.5 mm rut depth as the standard HMA pass-fail screening criteria. However, with the record high summer temperatures of the recent years in Texas, several premature field rutting failures have occurred with some HMA mixes that had passed the HWTT screening criteria in the laboratory. This laboratory study was thus initiated to review and evaluate if the current Texas HWTT protocol and its associated Texas Test Specification (Tex-242-F) are simulative of the current summer field conditions for routine HMA mix-design and screening to optimize rutting resistance performance. Specifically, two key aspects were evaluated, namely the HMA sample sitting time and Test temperature. The corresponding laboratory Test results indicated that a maximum sample sitting time of five days should be consistently adapted, i.e., lab-molded samples should be Tested within five days of fabrication, particularly for HMA mix-design screening purposes. For HMA mixes to be used in high temperature/stress environments, the study findings suggested that higher (>50 °C), and/or multiple HWTT Test temperatures should be considered.
