Gas chromatographic separation of linoleic acid hydroperoxides as trimethylsilyl ethers of methyl hydroxystearates

The primary products, 9- and 13-hydroperoxy-octadecadienoic acids, from lipoxygenase catalyzed oxidation of linoleic acid, were converted into the trimethylsilyl ethers of methyl 9- and 13-hydroxystearates which were completely separated by gas chromatography on an OV-17 methyl silicone (50% phenyl groups), capillary column.     

Turbulent Flow over a Channel with Fluid-Saturated Porous Bed

The characteristics of fully developed turbulent flow in a hybrid domain channel, which consists of a clear fluid region and a porous bed, are examined numerically using a model based on the macroscopic Reynolds-averaged Navier–Stokes equations. By adopting the classical continuity interface conditions, the present model treats the hybrid domain problem with a single domain approach, and the simulated results are noted to coincide with the existing experimental data and microscopic data. The effects of porosity ? and Darcy number Da on the flow properties over and inside the porous bed are further investigated in the selected ranges of 0.6 ? ? ? 0.8, and 1.6×10?4 ? Da ? 1.6×10?2. It has been demonstrated that the presence of the porous bed causes the significant reduction of the flow velocities inside the clear fluid region relative to that of a smooth impermeable bed, and also reduces the magnitude of the integral constant B of the velocity logarithmic distributions from its traditional value 5.25. Moreover, turbulent shear stress within the upper part of the porous bed increases significantly with the porosity ? and Darcy number Da. The thickness of turbulence penetration remains proportional to the values of porosity ? and Darcy number Da.     

Force recovery procedures in nonlinear analysis

Conventionally, incremental-iterative schemes have been used in solving nonlinear problems. There are two phases involved in such analyses. The first or ‘predictor’ phase relates to solution of the structural displacement increments from the total incremental equations of equilibrium, while the second or ‘corrector’ phase is concerned with recovery of the element forces from the element displacement increments obtained in the first phase. In this paper, it will be demonstrated that accuracy of the numerical solutions depends primarily on the corrector or procedure for recovering the element forces. The expression used in the predictor can only affect the number of iterations required at each incremental step, but not the final shape of the load-deflection curves. A key factor in selecting the procedure for force recovery is that higher order nonlinear effects must be included, based on rigorous continuum mechanics formulations.     

Graphite-based indirect laser sintered fuel cell bipolar plates containing carbon fiber additions

Critical considerations for laser sintered (LS) graphite bipolar plates are the strength of the parts in the green, brown and finished states as well as the final part electrical conductivity. The effect of 0-26 volume percent chopped carbon fiber (CF) on strength and electrical conductivity of LS graphite bipolar plates was evaluated. Fiber additions improved the green and brown strength significantly. Finished part flexural strength increased from 35 MPa to almost 50 MPa with CF additions. The electrical conductivity of finished parts was lowered by CF additions.     

Interruptible load control for Taiwan Power Company

Three alternative incentive rate designs for an interruptible load program are described, one of which was activated by Taiwan Power Company (Taipower) in 1987 when some preliminary results were obtained. Here, the effect of the interruptible load on the system peak demand reduction and the change of daily load curve for large industrial customers is analyzed. The avoided cost is estimated and a more appropriate incentive rate structure is designed for the interruptible load program. The interruptible load program has reduced the system peak load in the Taipower system by 270 MW or 2.4% of the yearly peak demand     

Synthesis and properties of organosoluble polyimides derived from 2,2′‐dibromo‐ and 2,2′,6,6′‐tetrabromo‐4,4′‐oxydianilines

Two new aromatic diamines, 2,2′‐dibromo‐4,4′‐oxydianiline (DB‐ODA 4 ) and 2,2′,6,6′‐tetrabromo‐4,4′‐oxydianiline (TB‐ODA 5 ), have been synthesized by oxidation, bromination, and reduction of 4,4′‐oxydianiline (4,4′‐ODA). Novel polyimides 6a–f and 7a–f were prepared by reacting DB‐ODA ( 4 ) and TB‐ODA ( 5 ) with several dianhydrides by one‐step method, respectively. The inherent viscosities of these polyimides ranged from 0.31 to 0.99 dL/g (0.5 g/dL, in NMP at 30°C). These polyimides showed enhanced solubilities compared to those derived from 4,4′‐oxydianiline and corresponding dianhydrides. Especially, polyimides 7a , derived from rigid PMDA and TB‐ODA ( 5 ) can also be soluble in THF, DMF, DMAc, DMSO, and NMP. These polyimides also exhibited good thermal stability. Their glass transition temperatures measured by thermal mechanical analysis (TMA) ranged from 251 to 328°C. When the same dianhydrides were used, polyimides 7 containing four bromide substituents had higher glass transition temperatures than polyimides 6 containing two bromide substituents. The effects of incorporating more polarizable bromides on the refractive indices of polyimides were also investigated. The average refractive indices (n_av) measured at 633 nm were from 1.6088 to 1.7072, and the in‐plane/out‐of‐plane birefringences (Δn) were from 0.0098 to 0.0445. It was found that the refractive indices are slightly higher when polyimides contain more bromides. However, this effect is not very obvious. It might be due to loose chain packing resulted from bromide substituents at the 2,2′ and 2,2′,6,6′ positions of the oxydiphenylene moieties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Integrating data mining with KJ method to classify bridge construction defects

This paper tries to analyze common bridge construction defects, classify them into appropriate groups, and redefine them as a precautionary measure and means to improve quality in bridge construction. For this purpose, data on bridge construction since January 2007 were obtained from the evaluation report of the Public Construction Committee (PCC) of Taiwan. Bridge construction defects were classified according to their characteristics. A constraint-based clustering method and affinity diagram (KJ method) are proposed and used. This method can simultaneously treat mixed data types; moreover, it can incorporate user-specified constraints. The quality or safety issues, the unit-in-charge (Government authorities/project owners/contractor), and the properties of the defects (construction/audit/documents/others) are the sorting attributes. The constraint is avoiding empty clusters or clusters having very few objects. The results revealed five major defect classifications: safety and environment, construction site defects, supervision/control process, construction quality documents, and others.     

A mouse molecular mimic of human vascular adhesion protein-1

Human vascular adhesion protein-1 (VAP-1) is an endothelial sialoglycoprotein which exists in forms of Mr 90000 and 170000 and mediates lymphocyte binding to vessels under shear. VAP-1 is functionally defined by an inhibitory mouse mAb 1B2. A large-scale immunoaffinity purification of VAP-1 from human tonsil lysates was performed to determine the protein sequence for VAP-1 cDNA cloning. A dominant protein of molecular weight 90000 was obtained which yielded an N-terminal sequence of 20 amino acids which bore no significant identity to any protein sequence in the data banks. A mouse mAb (5B11) against a synthetic peptide from this sequence was raised and found to stain tissues in an identical manner to mAb 1B2, to inhibit lymphocyte adhesion to endothelial cells and to recognize VAP-1. Later, the N-terminal sequence obtained from the 1B2 immunoprecipitations was found to be identical to a mouse cyclophilin C associated protein (mCyCAP) subsequently published by others. We show here by several criteria at the protein and DNA level that VAP-1 is distinct from mCyCAP. Moreover, we elucidate the mechanism which results in binding of mCyCAP to mAb 1B2 during antibody synthesis in hybridoma cells and the sequelae of co-precipitation of mCyCAP during the immunoaffinity chromatography. Binding of mCyCAP to a mouse mAb has not been described before and suggests a new function for this molecule in immunoglobulin synthesis and/or secretion. Moreover, these data indicate that the N-terminal peptide of mCyCAP is a molecular mimic of a functionally important epitope of VAP-1.     

Freeze-form extrusion fabrication of ceramic parts

A novel, environmentally friendly solid freeform fabrication method called freeze-form extrusion fabrication (FEF) has been developed for the fabrication of ceramic-based components. The method is based on deposition of ceramic pastes using water as the media. The ceramic solids loading can be 50 vol.% or higher and initial studies have focused on the use of aluminum oxide (Al₂O₃). The FEF system components and their interaction are examined, and the main process parameters affecting part geometry defined. Three-dimensional shaped components have been fabricated by extrusion deposition of the ceramic paste in a layer-by-layer fashion. The feasibility of this process has been demonstrated by building components having a simple geometry, such as cylinders and solid or hollow cones. Hollow cones have also been fabricated to demonstrate the ability to build structures with sloped walls.