Browsing by Subject "Extrusion"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Chemical and Physical Properties of Breakfast Cereals and Snacks Made from Specialty Sorghums and Sorghum Bran Using Twin Screw Extruder(2012-02-14) Asif, MuhammadWhole ground white, high tannin and black sorghum with and without additional high tannin sorghum bran were used in different proportions to develop ready to eat breakfast cereals and snacks. The effect of extrusion on the phenolic compounds and on in vitro starch digestibility of sorghum based cereals and snacks were observed. Gluten free and gluten containing breakfast cereal and snacks were developed with different physical, chemical and sensory characteristic. By increasing the sorghum and bran level in the formulations, the bulk density of extrudates was increased while expansion ratio was decreased. Bowl life of extrudates was increased up to 18 min. when 60% whole ground white sorghum was used with additional 10% high tannin sorghum bran. Water soluble index was significantly higher for the extrudates without additional bran and decreased as bran was added. A positive correlation between water soluble index and expansion ratio (R^2=0.89) indicated that the more expansion ratio provided a large surface area for water to interact with starch and other soluble components. The retention of total phenols in these extrudates varied from 13-41% and it was found that extrudates with additional high tannin sorghum bran had more total phenols than extrudates without it. Sorghum extrudates showed a significant reduction in antioxidant activity varied from 21-83%. Similarly, the effect of extrusion on condensed tannins was detrimental, and their retention was ranged from 12-28%. The smaller particle size of ground sorghum increased the surface area of contact between composite flour components and extruder barrel which promoted interactions during extrusion, lowering condensed tannins and antioxidant activity. All sorghum based extrudates had significantly (P<0.05) lower starch digestibility than that of corn flour extrudates. All types of sorghum had non-significant difference in starch digestibility from 0.5-2hrs. After 16 hrs., high tannin sorghum extrudates had the lowest starch digestibility (79%), which was significantly different from other sorghum types. There was a negative correlation between the rapid digestible starch and tannin contents (R^2=0.62). Breakfast cereals made from different types of sorghum and bran levels were statistically equally rated in taste and overall acceptability.Item Crystal-Like geometric modeling(Texas A&M University, 2006-08-16) Landreneau, Eric BenjaminCrystals 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.Item Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors(2012-02-14) Hausaman, Jeffrey StephenThe 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.Item Prediction of energy absorption of extruded tubes(Texas Tech University, 2000-12) Sun, JunningIn this study, the FE crush analysis was carried out using LS-DYNA. It is an advanced general purpose nonlinear FE program. LS-DYNA is suited to handle the large deformations, sophisticated material models, and complex contact interactions required to analyze crash simulations. The objective of this study was to investigate the effect of five parameters on the energy absorption of extruded tubes. The five parameters considered were: imperfection location, cross-section, impact velocity, cutout size, cutout location, and impact mass size. It was shown that the circular and hexagonal extrusions had a high energy absorption efficiency compared to triangular ones. However, the triangular extrusions had the lowest crush peak force. Additionally, cutouts introduced in the sides of the extrusions lowered the crush peak force. Increasing the kinetic energy of the impacting mass was shown to increase the crushing distance, while also increasing the peak force slightly. Finally, it was further showm that cutout and imperfection location influenced the tube folding pattern.Item The effect of flaxseed hulls on expanded corn meal products(2009-05-15) Barron, Marc EdwardBrown 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.