Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol)

Poly(ethylene glycol) (PEG) was ‘polymerized’ onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-cut test, contact angle measurements and static platelet adhesion studies. The modified surface, believed to be extensively cross-linked, however showed all the chemical characteristics of PEG. The surface was found to be highly hydrophilic as evidenced by an interfacial free energy of about 0.7 dynes/cm. AFM studies showed that the surface of the modified PET became smooth by the plasma polymerized deposition. Static platelet adhesion studies using platelet rich plasma (PRP) showed considerably reduced adhesion of platelets onto the modified surface by SEM. Plasma ‘polymerization’ of a polymer such as PEG onto substrates may be a novel and interesting strategy to prepare PEG-like surfaces on a variety of substrates since the technique allows the formation of thin, pin-hole free, strongly adherent films on a variety of substrates.     

Modification of hypoeutectic low alloy white cast irons

In order to modify the continuous network of eutectic cementite normally found in low alloy white cast irons into a dispersive distribution, strategies of controlling the morphology of eutectic cementite by additives are discussed. Qualitative arguments are presented and applied to the development of a complex modifier REAINTi. With the addition of this modifier to low carbon white cast irons nearly one fifth of the original eutectic cementite network can be modified into blocky particles in the plane of polish, and one third into isolated irregular ones. The experimental data shows that Ti(CN) may act as an effective nucleant or a grain refiner for eutectic cementite. The modification effects of rare earth elements are attributed to their abilities to purify the melt, promote divorced eutectic growth and refine the microstructure. Aluminium contributes to the modification by its purification effect.     

Reduction of NRRO in ball bearings for HDD spindle motors

In this paper, it is theoretically and experimentally analyzed that the non-repetitive run-out (NRRO) of a ball bearing is caused by geometrical errors of the inner and outer races and the balls, and the number of balls.

The results are summarized as follows:

(1) As for the geometrical errors of the inner and outer races, it is possible to reduce the NRRO to be less than 1 nm by choosing 12 or 18 number of balls, even if the inner and outer races have a harmonic undulation of less than the 11th order.

(2) The NRRO of a ball bearing with 12 balls is very small even if the geometrical errors of ball bearing parts are large. It was confirmed that 12 was an optimal number of balls for ball bearings used for HDD spindle motors.

     

Characterization of germanium implanted Si1−xGex layer

Characterization of a Si_1−xGe_x layer formed by high-dose germanium implantation and subsequent solid phase epitaxy is reported. Properties of this layer are obtained from electrical measurements on diodes and transistors fabricated in this layer. Results are compared with those of the silicon control devices. It was observed that the germanium implantation created considerable defects that are difficult to eliminate with annealing. These defects result in boron deactivation in the p-type regions of the devices, giving rise to larger resistance. Optimization of the device structure and fabrication process is discussed.     

The effect of washing and heat treatment on the surface characteristics of fluorocarbon resin-treated polyester

Polyester fabrics and films treated with two fluorocarbon resins were washed and heat treated. Water repellency, surface tension and ESCA measurements were carried out. Changes in the water repellency of the resin-treated polyester fabric caused by washing and heat treatment are related to modification of the chemical composition of the polyester surface.     

Decreased beta-phenylethylamine in CSF in Parkinson's disease

OBJECTIVE: To determine the concentrations of beta-phenylethylamine (PEA) in CSF in patients with Parkinson's disease, and to evaluate the relation between concentration of PEA in CSF and severity of Parkinson's disease. METHODS: Using gas chromatography-chemical ionisation mass spectrometry, CSF concentrations of PEA were measured in 23 patients with Parkinson's disease (mean age, 64.0 (SD 8.2) years), of whom three were at Hoehn and Yahr stage II, 11 were at stage III, and nine were at stage IV. Comparison was made with eight patients with neuropathy (mean age, 57.0 (SD 19.2) years) and 12 controls without neurological disease (mean age, 57.6 (SD 4.8) years). RESULTS: Concentrations of PEA in CSF in Parkinson's disease were significantly lower (mean 205 (SD 131) pg/ml) than in patients with peripheral neuropathy (433 (SD 254) pg/ml) and controls (387 (SD 194) pg/ml). The concentrations of PEA in CSF correlated negatively with Hoehn and Yahr stage (P<0.01). CONCLUSIONS: There are decreased CSF concentrations of PEA in patients with Parkinson's disease.     

Recrystallization-etch approach to study the plastic energy absorbtion at crack initiation and extension of pressure-vessel steel A533B-1

To evaluate the elastic-plastic fracture toughness parameter of nuclear pressure-vessel steel A533B-1, a newly developed technique (the recrystallization-etch technique) for plastic strain measurement was applied to different sizes of compact tension specimens with a crack length/specimen width of 0.6–0.5 that were tested to generate resistance curves for stable crack extensions. By means of the recrystallization-etch technique, the plastic energy dissipation or work done within an intense strain region at the crack tip during crack initiation and extension was measured experimentally. Furthermore, the thickness effects on this crack tip energy dissipation rate were examined in comparison with other fracture-parameter J integrals. Thickness effects on critical energy dissipation and energy dissipation rate during crack extension were obtained and the energy dissipation rate dW _p/da in the mid-section shows a constant value irrespective of specimen geometry and size, which can be used as a fracture parameter or crack resistance property.