Pressure-assisted infiltration of molten metals into non-rigid, porous carbon fibre structures

Abstract Mercury intrusion porosimetry has been conducted on a range of non-rigid, porous carbon fibre structures. Comparison with data from gas pressure infiltration experiments in a molten Al-Si alloy shows it to be a useful tool in determining the pressure required to produce Al metal matrix composites with low levels of porosity. Whilst for non-rigid fibre preforms, as studied here, it is difficult to pin-point every aspect of the infiltration process, the method does give an indication of critical aspects of the infiltration behaviour. Preforms made from loose and spread tow can be fully infiltrated at relatively low pressures (12 bar) and although metal can fill the spaces between fibre bundles within textile-based preforms at low pressures, densely-packed bundles are only infiltrated at higher pressures, usually in excess of 50 bar. Mercury intrusion porosimetry could provide a valuable and simple tool in the design of fibre-reinforced metal matrix composites with optimised structures that are easy to manufacture

Chromospheric activity in 55 Cancri: II. Theoretical wave studies versus observations

Stars and planetary system

Multicolour interphase cytogenetics: 24 chromosome probes, 6 colours, 4 layers

From the late 1980s onwards, the use of DNA probes to visualise sequences on individual chromosomes (fluorescent in-situ hybridisation - FISH) revolutionised the study of cytogenetics. Following single colour experiments, more fluorochromes were added, culminating in a 24 colour assay that could distinguish all human chromosomes. Interphase cytogenetics (the detection of chromosome copy number in interphase nuclei) soon followed, however 24 colour experiments are hampered for this application as mixing fluorochromes to produce secondary colours produces images that are not easily distinguishable from overlapping signals. This study reports the development and use of a novel protocol, new fast hybridising FISH probes, and a bespoke image capture system for the assessment of chromosome copy number in interphase nuclei. The multicolour probe sets can be used individually or in sequential hybridisation layers to assess ploidy of all 24 human chromosomes in the same nucleus. Applications of this technique are in the investigation of chromosome copy number and the assessment of nuclear organisation for a range of different cell types including human sperm, cancer cells and preimplantation embryos

Does modafinil enhance activity of patients with myotonic dystrophy?: A double-blind placebo-controlled crossover study

We performed a double-blind placebo-controlled crossover study in 13 patients with myotonic dystrophy to address the question whether modafinil, known to improve hypersomnolence in myotonic dystrophy, may improve levels of activity as well. We used the Epworth Sleepiness Scale as a measure of hypersomnolence and a structured interview of the patient and the partner or housemate as a measure of activity. We additionally used a restricted form of the RAND-36 to relate a possible improvement of activity to perceived general health. We confirmed earlier positive findings of modafinil regarding reduced somnolence (p = 0.015), but no significant effects were seen regarding activity levels (p = 0.2 for patients’ self-reports and 0.5 for partners’ reports)

A water-soluble core material for manufacturing hollow composite sections

This paper presents the development of a low-cost water-soluble core material, which is suitable for producing hollow composite structures via high pressure moulding processes, such as compression moulding and resin transfer moulding. The bulk material of the core is sodium chloride (NaCl), which is held together by a watersoluble trehalose binder. The composition of the core has been optimised to provide acceptable dissolution rates and mechanical properties for high volume structural composite applications. The compressive strength of the NaCl core was 57 MPa at ambient temperature, which reduced to 20 MPa when tested at 120 °C. The compressive strength at elevated temperature was approximately 4 times higher than for a water-soluble commercial benchmark and 33 times higher than a conventional structural closed-cell foam. The specific dissolution rate of the NaCl core was between 0.14 and 1.23 kg/(min·m2), depending on processing parameters and the coefficient of thermal expansion was approximately 43 × 10−6/K. A practical example has been presented to demonstrate how the removable core can be used to produce a representative hollow section of an integrally stiffened panel

A Monitor of Beam Polarization Profiles for the TRIUMF Parity Experiment

TRIUMF experiment E497 is a study of parity violation in pp scattering at an energy where the leading term in the analyzing power is expected to vanish, thus measuring a unique combination of weak-interaction flavour conserving terms. It is desired to reach a level of sensitivity of 2x10^-8 in both statistical and systematic errors. The leading systematic errors depend on transverse polarization components and, at least, the first moment of transverse polarization. A novel polarimeter that measures profiles of both transverse components of polarization as a function of position is described.Comment: 19 pages LaTeX, 10 PostScript figures. To appear in Nuclear Instruments and Methods in Physics Research, Section