摘要 :
Methods for the production of functionally graded material (FGM) are provided. FGM is processed by powder cold spraying ceramic-metal layers, the final shape is pre-pressed by cold isostatic pressing and is then sintered using fie...
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Methods for the production of functionally graded material (FGM) are provided. FGM is processed by powder cold spraying ceramic-metal layers, the final shape is pre-pressed by cold isostatic pressing and is then sintered using field activated sintering technique (FAST). The FGM materials can be used for medical applications.
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The overall goal of this particular study was to provide proof of concept through modeling and simulation to predict the impact of a functionally graded material (FGM)-based target on the shockwaves generated from an impactor. Mos...
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The overall goal of this particular study was to provide proof of concept through modeling and simulation to predict the impact of a functionally graded material (FGM)-based target on the shockwaves generated from an impactor. Most armor systems are comprised of a single material or a composite layup of several materials. The intent of this study was to provide insight into the effectiveness of morphed microstructure consisting of a glass and transparent ceramic FGM.
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This is the final progress report of activities at Texas Engineering Experiment Station (TEES)/Texas A&M University (TAMU) on work related to the AFOSR Defense University Research Instrumentation Program (DURIP) Project titled, Acquisition of Mechanically Assisted Spark Plasma Sintering System for Advanced Research and Education on Functionally Graded Hybrid Materials . The effective beginning date of Contract No. FA9550-10-1-0398 was September 15, 2010. The project was aimed at developing facilities for pressure-assisted fabrication of hybrid materials by spark plasma sintering (SPS) of metallic and ceramic powders to support a wide range of research AFOSR activities that cannot be easily achieved using existing facilities at Texas A&M University, including MURI project entitled Synthesis, Characterization, and Prognostic Modeling of Functionally Graded Hybrid Composites for Extreme Environments . Several different components were acquiring, installed and tested the proposed systems have been successfully installed at Texas A&M University. Different MAX phases, as well as their composites with the Shape Memory Alloys (SMA) have been fabricated and they demonstrated unprecedented mechanical damping due to residual stresses in MAX phases induced by the shape memory effect. In addition, the SPS was used to join ceramics (MAX phases) to the SMA (NiTi) and study the kinetics of the interfacial reactions. The acquired SPS fabrication system is one of the most powerful in the academia and will allows us to systematically fabricate and study structural, physical and mechanical properties of these hybrid materials....
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This is the final progress report of activities at Texas Engineering Experiment Station (TEES)/Texas A&M University (TAMU) on work related to the AFOSR Defense University Research Instrumentation Program (DURIP) Project titled, Acquisition of Mechanically Assisted Spark Plasma Sintering System for Advanced Research and Education on Functionally Graded Hybrid Materials . The effective beginning date of Contract No. FA9550-10-1-0398 was September 15, 2010. The project was aimed at developing facilities for pressure-assisted fabrication of hybrid materials by spark plasma sintering (SPS) of metallic and ceramic powders to support a wide range of research AFOSR activities that cannot be easily achieved using existing facilities at Texas A&M University, including MURI project entitled Synthesis, Characterization, and Prognostic Modeling of Functionally Graded Hybrid Composites for Extreme Environments . Several different components were acquiring, installed and tested the proposed systems have been successfully installed at Texas A&M University. Different MAX phases, as well as their composites with the Shape Memory Alloys (SMA) have been fabricated and they demonstrated unprecedented mechanical damping due to residual stresses in MAX phases induced by the shape memory effect. In addition, the SPS was used to join ceramics (MAX phases) to the SMA (NiTi) and study the kinetics of the interfacial reactions. The acquired SPS fabrication system is one of the most powerful in the academia and will allows us to systematically fabricate and study structural, physical and mechanical properties of these hybrid materials.
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On May 28, 2013, about 1:59 p.m., a 2003 Mack Granite truck, operated by Alban Waste, LLC, was traveling northwest on a private road in Rosedale, Maryland, toward a private grade crossing. The truck was carrying a load of debris t...
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On May 28, 2013, about 1:59 p.m., a 2003 Mack Granite truck, operated by Alban Waste, LLC, was traveling northwest on a private road in Rosedale, Maryland, toward a private grade crossing. The truck was carrying a load of debris to a recycling center located 3.5 miles from the carrier terminal. About the same time, a CSX Transportation Company (CSXT) freight train—which consisted of two locomotives, 31 empty cars, and 14 loaded cars—was traveling southwest at a speed of 49 mph. As the train approached the crossing, the train horn sounded three times. The truck did not stop and was hit by the train. Three of the 15 derailed cars contained hazardous materials. The other derailed cars contained non-US Department of Transportation-regulated commodities, or were empty. One car loaded with sodium chlorate crystal and four cars loaded with terephthalic acid released their products. Following the derailment, a post-crash fire resulted in an explosion at 2:04 p.m., which caused widespread property damage. The fire remained confined to the derailed train cars. The truck driver was seriously injured in the collision. Three workers in a building adjacent to the railroad tracks and a Maryland Transportation Authority police officer who responded to the initial incident received minor injuries as a result of the explosion. Major safety issues identified in this investigation were distraction, federal oversight of new entrant motor carriers, obstructive sleep apnea, safety systems at private grade crossings, and oxidizing and flammable or combustible materials. The National Transportation Safety Board makes recommendations to the Federal Motor Carrier Safety Administration; the Federal Railroad Administration; the 50 states, the District of Columbia, and the Commonwealth of Puerto Rico; the Association of American Railroads; the American Short Line and Regional Railroad Association; the National Fire Protection Association; and CSXT.
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Conventional test methods for roadway compaction cover less than 1% of roadway; whereas, intelligent compaction (IC) offers a method to measure 100% of a roadway. IC offers the ability to increase compaction uniformity of soils an...
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Conventional test methods for roadway compaction cover less than 1% of roadway; whereas, intelligent compaction (IC) offers a method to measure 100% of a roadway. IC offers the ability to increase compaction uniformity of soils and asphalt pavements, which leads to decreased maintenance costs and an extended service life. This report examines IC technology, how IC quality control and assurance specifications can encourage IC adoption, knowledge and use of IC through survey responses, and benefits and costs of IC. The surveys reveal that a majority of respondents from state departments of transportation have conducted IC demonstration projects, but questions about cost and willingness of policymakers to adopt IC remain a barrier to implementation. The benefit-cost analysis demonstrates that use of IC reduces compaction costs by as much as 54% and results in a $15,385 annual savings per lane mile throughout the roadway’s life.
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A comprehensive research program coupling thermalacoustic- mechanical flight loads to guide the design of multi-functional Functionally Graded Hybrid Composite (FGHC) systems with integrated sensing capabilities for extreme environments.
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This report describes the conclusion and recommendations of the CompositesResearch Advisory Group (CRAG) working group on alternative equivalent materials for components cleared primarily by structural testing. The requirement for...
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This report describes the conclusion and recommendations of the CompositesResearch Advisory Group (CRAG) working group on alternative equivalent materials for components cleared primarily by structural testing. The requirement for the Working Group arose from the identification that, due to insufficient understanding of composite behaviour, the introduction of an alternative material to a composite structure seldom occurred as extensive retesting is required. This clearly reduces the cost effectiveness of composite structures as the commercial advantages of multi-sourcing cannot be attained. It was also identified that the classification of the structure was a major factor in the case of alternative material selection and introduction.
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The reclamation of surface mined areas satisfies two important objectives. First, reclaimed lands reduce the environmental degradation of the disturbed property as well as the surrounding area by controlling erosion and subsequent...
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The reclamation of surface mined areas satisfies two important objectives. First, reclaimed lands reduce the environmental degradation of the disturbed property as well as the surrounding area by controlling erosion and subsequent sedimentation and by abating hydrologic contamination from exposed toxic materials. Second, reclamation restores the disturbed area to a productive land use. This use could be agricultural, industrial, residential, recreational, or simply the restoration of the land's aesthetic value. Backfilling and grading represent two essential elements in the process of disturbed land reclamation. If these two functions are not properly executed, the success of the entire reclamation operation can be jeopardized. The manual provides assistance in defining backfilling and grading requirements and the options available to efficiently satisfy those requirements.
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