New polymer/steel solution for automotive applications

Dry and wet steel/polymer adhesion was investigated using pull-off test and dielectric measurements. The influence of the composition of a hexafluorotitanic acid based surface treatment (Patent WO9607772A1) was also studied. It was noticed that when manganese or organic phase was missing from surface treatment, breaking force level decreases and steel surface was not protected from water effects. After ageing and drying, a complete recovery in breaking force was noticed except for treatment without the organic phase.     

Preparation and Properties of Bi4 − x Nd x Ti3O12 Thin Films by Chemical Solution Deposition

Neodymium-modified Bi₄Ti₃O₁₂, (Bi, Nd)₄Ti₃O₁₂ (BNT) ferroelectric thin films have been prepared on Pt/TiO_x/SiO₂/Si substrates using metal-organic precursor solutions by the chemical solution deposition method. The BNT precursor films crystallized into the Bi layered perovskite Bi₄Ti₃O₁₂ (BIT) as a single-phase above 600C. The synthesized BNT films revealed a random orientation having a strong 117 reflection, whereas non-substituted BIT thin films exhibited a random orientation with strong 00l diffractions. Among Bi_{4 – x}Nd_xTi₃O₁₂ [x = 0.0, 0.5, 0.75, 1.0] thin films, Bi_3.25Nd_0.75Ti₃O₁₂ thin films showed a well-saturated P-E hysteresis loop with the highest P_r (22 C/cm²) and a low E_c (69 kV/cm) at an applied voltage of 5 V. The Nd-substitution with the optimum amount for the Bi site in the BIT structure was effective not only for promoting the 117 preferred orientation but also for improving the microstructure and ferroelectric properties of the resultant films.     

The role of surface plasmons in organic light-emitting diodes

Organic light-emitting diodes typically take the form of an optical microcavity in which one layer is a metallic cathode. Coupling between emissive species in the light emitting layer and surface plasmon (SP) modes associated with the metallic cathode result in a loss of efficiency; an aspect often discussed but not so far fully quantified. Here we numerically model the extent of this problem, both for organic light-emitting diodes based on small molecules (Alq₃) and those based on conjugated polymers (MEH-PPV). We show that SP modes can significantly detract from device efficiency, particularly those based on small molecules. We then report measurements of photo- and electroluminescence from organic light-emitting diodes incorporating wavelength scale periodic structure. These data demonstrate the existence of the SP modes in organic light-emitting diodes. Finally we consider ways in which the problems associated with SPs might be overcome, and may even be turned to advantage     

Sterols of the oyster,Crassostrea virginica

A commericial sample of the oyster,Crassostrea virginica, obtained from Maryland waters of the Chesapeake Bay, contained 31 desmethylesterols and at least eight 4-monomethylsterols. The combined gas liquid chromatography-mass spectra of the minor components showed the presence of 6 unusual sterols, 24-ethylcholest-22-en-3β ol, 4α-methyl-24-ethylcholestan-3β-ol, occelasterol, (24E)-24-propylidene-cholest-5-en-3β-ol, (24ZO-24-propylidene-cholest-5-en-3β-ol, and 24-methylene-cholestanol. The C-24 configuration of 24-ethylcholest-5-enol, 24-methyl-cholesta-5,22-dienol, and 24-ethylcholesta-5,22 dienol were elucidated by 220 MHz nuclear magnetic resonance spectrometry.     

Reversal Activity and Toxicity of Heparin-Binding Copolymer after Subcutaneous Administration of Enoxaparin in Mice

Uncontrolled bleeding after enoxaparin (ENX) is rare but may be life-threatening. The only registered antidote for ENX, protamine sulfate (PS), has 60% efficacy and can cause severe adverse side effects. We developed a diblock copolymer, heparin-binding copolymer (HBC), that reverses intravenously administered heparins. Here, we focused on the HBC inhibitory activity against subcutaneously administered ENX in healthy mice. BALB/c mice were subcutaneously injected with ENX at the dose of 5 mg/kg. After 110 min, vehicle, HBC (6.25 and 12.5 mg/kg), or PS (5 and 10 mg/kg) were administered into the tail vein. The blood was collected after 3, 10, 60, 120, 360, and 600 min after vehicle, HBC, or PS administration. The activities of antifactors Xa and IIa and biochemical parameters were measured. The main organs were collected for histological analysis. HBC at the lower dose reversed the effect of ENX on antifactor Xa activity for 10 min after antidote administration, whereas at the higher dose, HBC reversed the effect on antifactor Xa activity throughout the course of the experiment. Both doses of HBC completely reversed the effect of ENX on antifactor IIa activity. PS did not reverse antifactor Xa activity and partially reversed antifactor IIa activity. HBC modulated biochemical parameters. Histopathological analysis showed changes in the liver, lungs, and spleen of mice treated with HBC and in the lungs and heart of mice treated with PS. HBC administered in an appropriate dose might be an efficient substitute for PS to reverse significantly increased anticoagulant activity that may be connected with major bleeding in patients receiving ENX subcutaneously.     

Comparison of the wetting behaviour of polyamides presented as particles and films—Influence of a plasma microwave treatment

The wettability of two types of polyamide powder (ORGASOL_® and RILSAN), differing by their shape and chain ends, has been studied by three methods: inverse gas chromatography, capillary ascension and contact angle measurement on films obtained by the compression at room temperature of the powders. The results are compared with the contact angles measured on the films realized with the melted powders. All the techniques give the same classification of the wettability of the two kinds of polyamides but not the same absolute values of contact angles. In particular, the influence of the shape of the particles has been shown on ORGASOL_® by capillary ascension and by contact angle performed on films obtained by compression at room temperature of the powder. A N₂/O₂ plasma treatment applied to the particles leads to an increase of the water wettability of the powders but the treatment was found less efficient than on the melt powder based films.     

Electrochemical superabrasive machining of a nickel-based aeroengine alloy using mounted grinding points

Brief design and manufacture considerations are detailed for a hybrid electrochemical grinding unit adapted from a vertical machining centre using a 40,000 rpm spindle and 500 A DC generator. Subsequently, experimental work is presented on the influence of tool bond systems, superabrasive grit type and electrical parameters when simultaneous ECM/grinding Udimet 720 using 10-15 mm diameter plain points. Single layer electroplated CBN tools produced G-ratios and maximum normal cutting forces of ∼451 and ∼45 N, respectively, compared to ∼128 and 557 N for equivalent diamond wheels. Data on workpiece roughness and overcut are also presented as are initial results for a fir tree shaped tool.     

Processes for System Family Architecting, Design, and Integration

Today, many systems within government and industry are typically engineered, not as stand alone systems, but as part of an integrated system of systems, or a federation of systems, or systems family. A significant level of effort has been devoted in the past several years to the development, refinement, and ultimately, acceptance of processes for engineering systems or systems engineering processes. Today, we have four ldquostandardrdquo processes within present and past standards: EIA-632, IEEE 1220, ISO 15288, and MIL-STD-499C. We continue to use systems engineering processes espoused in our current set of standards, and are left to our devices to tailor these processes to one appropriate for a systems family context. This paper will examine the systems engineering processes in existence today and conclude with development of a process designed specifically for systems family applications.     

Synthesis and properties of carbons dispersed with α-iron particles from divinylbenzene-vinylferrocene

α-Iron-dispersed carbon was synthesized, through pressure pyrolysis of divinylbenzene-vinylferrocene above 750°C, and by reduction of magnetite-dispersed carbon. Divinylbenzenevinylferrocene copolymer was pyrolysed at 125 MPa above 750°C to yield carbons dispersed with α-iron accompanied by cementite. Magnetite in the carbon matrix was reduced to α-iron after heat treatments at 500°C in a flow of hydrogen. Carbons synthesized by the pressure pyrolysis of divinylbenzene-vinylferrocene at 800°C and 125 MPa contained iron-compound particles up to 200 nm, whereas the median diameter of α-iron particles in the carbon matrix after reduction treatments was 20 nm. α-Iron-dispersed carbon had a Curie temperature of 770°C. The saturation magnetization of iron-dispersed carbon increased with increasing the pyrolysis temperature of divinylbenzene-vinylferrocene copolymer, and reached a constant value of 183 e.m.u.g⁻¹ at 800°C. The saturation magnetization of α-iron-dispersed carbon after the reduction treatment revealed practically the theoretical value of α-iron. Carbons finely dispersed with only α-iron particles were synthesized successfully by reduction of magnetitedispersed carbons.     

Difference of histology and elemental composition of the cervical enamels among human permanent teeth

The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among the human permanent teeth. The reground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.