The Experts below are selected from a list of 1744203 Experts worldwide ranked by ideXlab platform
Laith Tashman - One of the best experts on this subject based on the ideXlab platform.
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Comparing Superpave Gyratory Compactor Data to Field Cores
Journal of Materials in Civil Engineering, 2004Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Achieving proper Compaction of asphalt pavement is crucial to its longevity and acceptable performance. Laboratory Compaction is an essential part of mix design. In order for the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. This study used mechanical properties measured with the Superpave shear tester to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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Superpave laboratory Compaction versus field Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, Kamyar C. Mahboub, Eyad Masad, R J Anderson, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave® shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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SUPERPAVE (REGISTERED TRADEMARK) LABORATORY Compaction VERSUS FIELD Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
Robert L. Peterson - One of the best experts on this subject based on the ideXlab platform.
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Comparing Superpave Gyratory Compactor Data to Field Cores
Journal of Materials in Civil Engineering, 2004Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Achieving proper Compaction of asphalt pavement is crucial to its longevity and acceptable performance. Laboratory Compaction is an essential part of mix design. In order for the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. This study used mechanical properties measured with the Superpave shear tester to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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Superpave laboratory Compaction versus field Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, Kamyar C. Mahboub, Eyad Masad, R J Anderson, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave® shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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SUPERPAVE (REGISTERED TRADEMARK) LABORATORY Compaction VERSUS FIELD Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
Karthik Nagarathnam - One of the best experts on this subject based on the ideXlab platform.
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Compaction of different boron carbide powders using uniaxial die Compaction and combustion driven Compaction
Journal of Materials Science, 2009Co-Authors: Kathy Lu, Karthik NagarathnamAbstract:Compaction of pure B4C and Ni2B nanolayer coated B4C was studied using uniaxial die Compaction and combustion driven Compaction techniques. Effects of different Compaction techniques and the Ni2B nanolayer around B4C particle surfaces on green B4C sample characteristics are the focus of this study. The combustion driven Compaction process yields much higher green density and strength than the uniaxial die Compaction process. For the samples obtained from the same Compaction technique, the Ni2B nanolayer on individual B4C particle surfaces improves the green density and strength of the B4C powder compacts. For the combustion driven Compaction process, optical images show micro-cracks on the surface of pure B4C compact while crack-free surface is observed for Ni2B nanolayer coated B4C sample. Scanning electron microscopy analysis shows the same trend as the green density and strength measurements. Combustion driven Compaction diagram for hard and brittle materials such as B4C is discussed.
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Compaction of different boron carbide powders using uniaxial die Compaction and combustion driven Compaction
Journal of Materials Science, 2009Co-Authors: Kathy Lu, Karthik NagarathnamAbstract:Compaction of pure B4C and Ni2B nanolayer coated B4C was studied using uniaxial die Compaction and combustion driven Compaction techniques. Effects of different Compaction techniques and the Ni2B nanolayer around B4C particle surfaces on green B4C sample characteristics are the focus of this study. The combustion driven Compaction process yields much higher green density and strength than the uniaxial die Compaction process. For the samples obtained from the same Compaction technique, the Ni2B nanolayer on individual B4C particle surfaces improves the green density and strength of the B4C powder compacts. For the combustion driven Compaction process, optical images show micro-cracks on the surface of pure B4C compact while crack-free surface is observed for Ni2B nanolayer coated B4C sample. Scanning electron microscopy analysis shows the same trend as the green density and strength measurements. Combustion driven Compaction diagram for hard and brittle materials such as B4C is discussed.
Jun Ichi Kuratsu - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the stability of small ruptured aneurysms with a small neck after embolization with guglielmi detachable coils correlation between coil packing ratio and coil Compaction
Interventional Neuroradiology, 2006Co-Authors: Yutaka Kai, Junichiro Hamada, Motohiro Morioka, Shigetoshi Yano, Jun Ichi KuratsuAbstract:It is difficult to predict the Compaction of Guglielmi detachable coils (GDC) after endovascular surgery for aneurysms. Therefore, we studied the relationship between the coil packing ratio and Compaction in 62 patients with acute ruptured intracranial aneurysms that were small (<10 mm) had a small neck (<4 mm) and were coil-embolized with GDC-10. We recorded the maximum prospective coil length, L, as the length that correspond with the volume of packed coils occupying 30% of the aneurysmal volume. L was calculated as L (cm) = 0.3 × a × b × c and the coil packing ratio expressed as packed coil length/L × 100, where a, b, and c are the aneurysmal height, length, and width in mm, respectively. Angiographic follow-up studies were performed at three months and one and two years after endovascular surgery. Of the 62 patients, 16 (25.8%) manifested angiographic coil Compaction (ten minor and six major Compactions); the mean coil packing ratio was 51.9 ±13.4%. The mean coil packing ratio in the other 46 patients was 80.5±20.2% and the difference was statistically significant (p<0.01). In all six patients with major Compaction the mean packing ratio was below 50%. We detected 93.8% of the Compactions within 24 months of coil placement. In patients with small, necked aneurysms, the optimal coil packing ratio could be identified with the formula 0.3 × a × b × c. The probability of Compaction was significantly higher when the coil packing ratio was under 50%. To detect coil Compaction post-embolization, follow-up angiograms must be examined regularly for at least 24 months.
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evaluation of the stability of small ruptured aneurysms with a small neck after embolization with guglielmi detachable coils correlation between coil packing ratio and coil Compaction
Neurosurgery, 2005Co-Authors: Yutaka Kai, Junichiro Hamada, Motohiro Morioka, Shigetoshi Yano, Jun Ichi KuratsuAbstract:OBJECTIVE Because it is difficult to predict the Compaction of Guglielmi detachable coils (GDCs) after endovascular surgery for aneurysms, we studied the relationship between the coil packing ratio and Compaction. Here, we propose a simple method for the preoperative estimation of coil Compaction. Using follow-up angiograms, we studied the timing and degree of coil Compaction in small terminal and side-wall aneurysms with narrow necks. METHODS We studied 62 patients with acute ruptured intracranial aneurysms that were small (<10 mm), had a small neck (<4 mm), and were coil embolized with GDC-10s. The aneurysmal volume was calculated using the equation V = 4/3pi(a/2) x (b/2) x (c/2), where a, b, and c are the aneurysmal height, length, and width in millimeters, respectively. The coil volume was calculated using the equation V = pi(p/2)2 x l x 10, where p represents the GDC-10 coil diameter (0.25 mm) and l is the coil length. We recorded the maximum prospective coil length, L, as that corresponding with the volume of packed coils occupying 30% of the aneurysmal volume. Therefore, L was calculated as L (cm) = 0.3 x a x b x c, and the coil packing ratio was expressed as packed coil length/L x 100. Angiographic follow-up studies were generally performed at 3 months and 1 and 2 years after endovascular surgery. We considered coil Compaction exceeding 2 mm as major Compaction and recorded minor Compaction when it was less than 2 mm of the empty reappeared space in the embolized aneurysm. Aneurysmal location was recorded as terminal or side wall. RESULTS Of the 62 patients, 16 (25.8%) manifested angiographic coil Compaction (10 minor and 6 major Compactions); the mean coil packing ratio was 51.9 +/- 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 +/- 20.2%, and the difference was statistically significant (P < 0.01). In all 6 patients with major Compaction, the mean packing ratio was less than 50% and all underwent re-embolization after a mean of 24.9 +/- 1.1 months. The 10 patients with minor Compaction were conservatively treated, and the degree of Compaction did not change during a mean period of 24 months. We detected 93.8% of the Compactions within 12 months of coil placement. The aneurysm was of the terminal type in 5 of the 6 patients with major coil Compaction. CONCLUSION In patients who underwent embolization with GDC-10s of aneurysms that were small and had a small neck, the optimal coil packing ratio could be identified with the formula 0.3 x a x b x c. The probability of coil Compaction was significantly higher when the coil packing ratio was less than 50%. To detect coil Compaction after embolization, follow-up angiograms must be examined regularly for at least 12 months. To detect major coil Compaction in patients with terminal type aneurysms, angiographic follow-up should not be shorter than 24 months.
Eyad Masad - One of the best experts on this subject based on the ideXlab platform.
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Comparing Superpave Gyratory Compactor Data to Field Cores
Journal of Materials in Civil Engineering, 2004Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Achieving proper Compaction of asphalt pavement is crucial to its longevity and acceptable performance. Laboratory Compaction is an essential part of mix design. In order for the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. This study used mechanical properties measured with the Superpave shear tester to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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Superpave laboratory Compaction versus field Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, Kamyar C. Mahboub, Eyad Masad, R J Anderson, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave® shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
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SUPERPAVE (REGISTERED TRADEMARK) LABORATORY Compaction VERSUS FIELD Compaction
Transportation Research Record, 2003Co-Authors: Robert L. Peterson, R Michael Anderson, Kamyar C. Mahboub, Eyad Masad, Laith TashmanAbstract:Laboratory Compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory Compaction must adequately simulate field Compaction. In this study mechanical properties measured with the Superpave shear tester were used to evaluate field Compaction and laboratory Compaction. The field Compaction consisted of three test sections with different Compaction patterns. The laboratory Compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.
