Brown flaxseed hulls were added to de-germed corn meal and processed into extrudates with acceptable texture and increased nutritional benefits. The addition of brown flaxseed hulls to a corn based expanded snack increases the dietary fiber, alpha omega 3 fatty acids, and antioxidants levels. The addition of flaxseed hulls to a corn based snack can increase its susceptibility to oxidative rancidity which can limit shelf life. Whole ground tannin sorghum with added brown flaxseed hulls was processed into extrudates and texture, antioxidant activity, and stability were evaluated. Brown flaxseed hulls were mixed with de-germed yellow corn meal in ratios of 0:100, 15:85, 20:80, and 25:75 (w/w) and extruded with 12 and 15% feed moistures using a twin screw extruder to produce direct expanded extrudates. Expansion of extrudates containing brown hulls decreased as the amount of hulls increased. Dried extrudates had acceptable flavor immediately after processing. Total phenols and antioxidant activity of extrudates containing 20 and 25% brown flaxseed hulls, extruded at 15% feed moisture were higher than de-germed corn meal extruded at 16% feed moisture. Brown flaxseed hulls were added at 20% to whole ground white and sumac (tannin) sorghums and processed into extrudates. Expansion increased for sorghum extrudates containing brown flaxseed hulls. The addition of brown flaxseed hulls increased antioxidant activity and total phenols of both white and sumac (tannin) extrudates. The sumac (tannin) extrudates had the longest delay in producing off odor (paintlike odor) and had the lowest p-Anisidine values compared to white (ATX631x RTX 436) sorghum and corn meal with added flaxseed hulls. Corn meal extrudates with 20% brown flaxseed hulls produce off odors more rapidly than other extrudates. This suggests that the tannins in sorghum maybe extending shelf life because of their antioxidant activity. The addition of brown flaxseed hulls can be used to increase nutritional value and antioxidant levels in a direct expanded product. Also the use of tannins sorghums in products containing flaxseed may help delay oxidation, thus preventing the occurrence of off odors. Further work needs to be done to verify results.

The development of fast reactor systems capable of burning recycled transuranic (TRU) isotopes has been underway for decades at various levels of activity. These systems could significantly alleviate nuclear waste storage liabilities by consuming the long-lived isotopes of plutonium (Pu), neptunium (Np), americium (Am), and curium (Cm). The fabrication of metal fuel alloys by melt casting pins containing the volatile elements Am and Np has been a major challenge due to their low vapor pressures; initial trials demonstrated significant losses during the casting process. A low temperature hot extrusion process was explored as a potential method to fabricate uranium-zirconium fuel alloys containing the TRU isotopes. The advantage of extrusion is that metal powders may be mixed and enclosed in process canisters to produce the desired composition and contain volatile components. Uranium powder was produced for the extrusion process by utilizing a hydride-dehydride process that was developed in conjunction with uranium alloy sintering studies. The extrusions occurred at 600 degrees C and utilized a hydraulic press capable of 450,000 N (50 tons) of force. Magnesium (Mg) metal was used as a surrogate metal for Pu and Am because of its low melting point (648 degrees C) and relatively high vapor pressure (0.2 atm at 725 degrees C). Samples containing U, Zr, and Mg powder were prepared in an inert atmosphere glovebox using copper canisters and extruded at 600 degrees C. The successful products of the extrusion method were characterized using thermal analysis with a differential scanning calorimeter as well as image and x-ray analysis utilizing an electron microprobe. The analysis showed that upon fabrication the matrix of the extruded metal alloy is completely heterogeneous with no mixing of the metal particle constituents. Further heat treating upon this alloy allows these different materials to interdiffuse and form mixed uraniumz-irconium phases with varying types of microstructures. Image and x-ray analysis showed that the magnesium surrogate present in a sample was retained with little evidence of losses due to vaporization.

Abstract Equal channel angular extrusion (ECAE) has been used to investigate the formation of submicron grain structures in copper deformed to ultra-high plastic strains by different die angles, deformation routes, and deformation temperatures. The result was characterized by the use of transmission election microscopy (TEM), and the evolution of the deformed Cu depended on several parameters such as die angle, deformation route, and deformation temperature. It has been demonstrated that the most effective method of forming high angle boundaries and recrystallized grains by severe plastic deformation is to rotate billets with a constant clockwise 90o between each pass (route BC) via a 90o die angle. Besides, the temperature effect on the microstructural evolution is studied. With increasing deformation temperature, the microstructure becomes more homogeneous because the climb and the cross-slip of dislocations are easier at higher temperatures, and the fraction of high angle boundaries, recrystallized grains and size of them are increased significantly with the deformation temperature. In addition, the thermomechanical process was also investigated in the present work. It is suggested that a uniform submicron grained structure could be obtained by increasing the deformation temperature and decreasing the intermediate annealing temperature to promote dynamic recovery and to inhibit discontinuous recrystallization.

A research object of this study is a extrusion of the composite rods. As the condition of the incompressibility, a set of stream functions was proposed by this study to construct analysis model of the conventional and the hydrostatic extrusion. The upper-bound approach was applied to investigate the plastic deformation behavior during composite rods extrusion. The topical subject of this study was consisted of conventional extrusion, hydrostatic extrusion and the instability of composite materials during conventional extrusion. This study proposes a set of stream functions to investigate the plastic deformation behavior of the rods during axisymmetric extrusion of composite rods through a conical die. The velocity field and the rigid-plastic boundaries can be obtained from the proposed stream functions immediately. Relative slip at the interface of the rods is allowed. The friction factor between the metal and die is determined by a ring compression test. By using the upper-bound approach, the radius ratio of the core layer at the exit of the die and the plastic region within the die are determined by the minimization of the total power. Experiments on extrusion of composite rods composed of aluminum (core layer) and copper (sleeve layer) are also carried out. The predicted force, final radius ratio and flow pattern of the rods within the die are compared with the experimental results. Being different with conventional extrusion, a condition that has relative slip at the interface of the rods at the exit of the die was modified to become no relative slip. The same set of stream functions with that of the conventional extrusion was also applied to simulate the flow behavior of the composite rods through a conical die during hydrostatic extrusion. This model is used to predict the hydrostatic extrusion pressure for various process parameters via the upper bound theorem. Experiments are also carried out using composite rods composed of copper as the sleeve layer and commercial aluminum as the core layer. The experimental results are compared with the theoretical calculations. A plastic instability criterion under a tri-axial stress state was developed in this study to predict the occurrence of plastic instability in the hard core layer during axisymmetric composite rod extrusion. Stress states in the hard core layer at the exit of the die, where plastic instability is most likely to occur, were employed to formulate the plastic instability criterion. The effects of various extrusion conditions, such as the initial radius ratio and yield stress ratio of the composite rods, etc., upon the critical area reduction, under which plastic instability can be avoided, were discussed systematically. Furthermore, experiments on composite rod extrusion were also conducted by employing aluminum and lead as layers of composite rods. It was found that the theoretical predictions of the critical area reduction were in good agreement with the experimental measurements with the initial area of 0.15.

This paper uses a finite element code¡©DEFORM 3D¡ªto simulate the plastic deformation behavior in extrusion processes of heat sink for CPU. The relationships between the loading, strain, velocity distribution, and formability of the extruded product as well as the extrusion conditions are discussed. Furthermore, this research will propose a criterion for the die design of heat sink and to prove the validity of this proposed criterion by the experiments.

Crystals are natural phenomena that exhibit high degrees of order, symmetry, and recursion. They naturally form interesting and inspiring geometric shapes. This thesis provides geometric modeling techniques for creating shapes with crystallike geometry. The tiered extrusion method, along with a face grouping technique, simplifies the creation of complex, intricate faceted shapes. In combination with remeshing, these methods provide the capability to generate geometric shapes exhibiting planar faces, symmetry, and fractal geometry. The techniques have also been implemented in software, as a proof of concept. They are used in an interactive geometric modeling system, in which users can use these techniques to create crystal-like shapes. The crystal-like modeling operations are shown to successfully create beautiful geometric shapes. The methods improve upon traditional modeling capabilities, providing an easier way to create crystal-like geometric shapes.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 129-134). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 129-134). Also available on the Internet.

published_or_final_version / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy

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