IMECE2002-33784 PROCESS MODELING OF SHAPE ROLLING FOR AEROSPACE INDUSTRY

ABSTRACT Shape rolling of seamless rings constitutes an efficient manufacturing process offering excellent material yield, energy conservation, and component production, which require a minimum of subsequent machining operations. An increasing number of rings are being produced from high temperature Titanium and Nickel based super alloy materials for gas turbine engine parts such as vane and fan casings, exhaust casings, turbine shrouds, and combustion liners. With the increasing cost of super alloy raw materials and growing demand for costcompetitive parts, the importance of ring rolling to contoured shape becomes an increasingly important factor. This paper describes a new process modeling technique based on Upper Bound Elemental Technique (UBET) for shape rolling of super alloys. This tool provides a new design paradigm for an industry relying to heavily on designer experience and cut-and-try methods. As a rapid software tool to aid designers in developing ring-rolling process schedules thereby helping in reducing the design and analysis cycle time, the potential to capture the unique 3-D flow situation experienced in shape rolling of seamless rings is being explored. Numerical results have been compared with data available for high temperature alloys such as IN718 and Ti6Al-4V

Titanium Alloyed with Boron

Small additions of boron to conventional titanium alloys have been found to produce significant changes to the microstructures and associated properties. Grain refinement and improved strength and stiffness are first-order effects, which lead to possibilities for developing novel and affordable processing methodologies and to enhance performance over conventional titanium alloys. In this article, we introduce this new class of titanium alloys and describe unique formability benefits achieved via engineering microstructures

Titanium Alloyed with Boron

Small additions of boron to conventional titanium alloys have been found to produce significant changes to the microstructures and associated properties. Grain refinement and improved strength and stiffness are first-order effects, which lead to possibilities for developing novel and affordable processing methodologies and to enhance performance over conventional titanium alloys. In this article, we introduce this new class of titanium alloys and describe unique formability benefits achieved via engineering microstructures

Chemical and genomic characterization of a potential probiotic treatment for stony coral tissue loss disease

A multidisciplinary approach identifies broad-spectrum antibacterial activity of Pseudoalteromonas sp. strain McH1-7 against stony coral tissue loss disease, which is threatening Caribbean coral reefs

Reconstitution of KCNE1 into Lipid Bilayers: Comparing the Structural, Dynamic, and Activity Differences in Micelle and Vesicle Environments

KCNE1 (minK), found in the human heart and cochlea, is a transmembrane protein that modulates the voltage-gated potassium KCNQ1 channel. While KCNE1 has previously been the subject of extensive structural studies in lyso-phospholipid detergent micelles, key observations have yet to be confirmed and refined in lipid bilayers. In this study, a reliable method for reconstituting KCNE1 into lipid bilayer vesicles composed of 1-palmitoyl-2-oleoyl-<i>sn</i>-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-<i>sn</i>-glycero-3-phospho­(1′-<i>rac</i>-glycerol) (sodium salt) (POPG) was developed. Microinjection of the proteoliposomes into <i>Xenopus</i> oocytes expressing the human KCNQ1 (K_V7.1) voltage-gated potassium channel led to nativelike modulation of the channel. Circular dichroism spectroscopy demonstrated that the percent helicity of KCNE1 is significantly higher for the protein reconstituted in lipid vesicles than for the previously described structure in 1.0% 1-myristoyl-2-hydroxy-<i>sn</i>-glycero-3-phospho­(1′-<i>rac</i>-glycerol) (sodium salt) (LMPG) micelles. SDSL electron paramagnetic resonance spectroscopic techniques were used to probe the local structure and environment of Ser28, Phe54, Phe57, Leu59, and Ser64 of KCNE1 in both POPC/POPG vesicles and LMPG micelles. Spin-labeled KCNE1 cysteine mutants at Phe54, Phe57, Leu59, and Ser64 were found to be located inside POPC/POPG vesicles, whereas Ser28 was found to be located outside the membrane. Ser64 was shown to be water inaccessible in vesicles but found to be water accessible in LMPG micelle solutions. These results suggest that key components of the micelle-derived structure of KCNE1 extend to the structure of this protein in lipid bilayers but also demonstrate the need to refine this structure using data derived from the bilayer-reconstituted protein to more accurately define its native structure. This work establishes the basis for such future studies