Thermal effects in high density polyethylene and low density polyethylene at high hydrostatic pressures

The temperature changes as a result of rapid hydrostatic pressure applications are reported for high density polyethylene (HDPE) and low density polyethylene (LDPE) in the reference temperature range from 298 to 423 K and in the pressure range from 13.8 to 200 MN m −2 . The adiabatic temperature changes were found to be a function of pressure and temperature. A curve fitting analysis showed that the empirical curve (∂/∂ P ) = ab (Δ P ) b−1 described the experimental thermoelastic coefficients obtained from the experiments. The data were analyzed by determining the predicted thermoelastic coefficients derived from the Thomson equation (∂/∂ P ) θ = α T 0 /ϱ C p . The experimental and predicted Grüneisen parameter γ T were also determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44687/1/10853_2005_Article_BF01132919.pd

Fracture behaviour of unmodified and rubber-modified epoxies under hydrostatic pressure

The fracture toughness and uniaxial tensile yield strengths of unmodified and CTBN-rubber-modified epoxies were measured under hydrostatic pressure. The purpose of these experiments was to learn how suppressing cavitation in rubber particles affects the deformation mechanisms and the fracture toughness of rubber-modified epoxy. It was found that the cavitation of CTBN-rubber could be suppressed at a relatively low pressure (between 30 and 38 M Pa). With cavitation suppressed, the rubber particles are unable to induce massive shearyielding in the epoxy matrix, and the fracture toughness of the rubber-modified epoxy is no higher than that of the unmodified epoxy in the pressure range studied. Unmodified epoxy shows a brittle-to-ductile transition in fracture toughness test. The reason for this transition is the postponement of the cracking process by applied pressure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44734/1/10853_2005_Article_BF01154701.pd

Brief Communication - DETECTION OF VANCOMYCIN RESISTANT STAPHYLOCOCCUS AUREUS: A COMPARATIVE STUDY OF THREE DIFFERENT PHENOTYPIC SCREENING METHODS

The objective of this study was to investigate screening methodologies, to detect Staphylococcus aureus strains with decreased susceptibility to vancomycin. Three methods were used to screen 160 Staphylococcus aureus clinical isolates along with ATCC quality control strains. Subsequently, MIC of all these 160 strains were determined by NCCLS methodology. The MIC of all the 160 clinical isolates was ≤ 4µg/mL and were classified as vancomycin susceptible by NCCLS criteria but 23 strains were positive by Hiramatshu method, two grew on MHA (5µg/mL vancomycin) while CDC method correctly identified no vancomycin intermediate S.aureus (VISA) or vancomycin resistant S.aureus (VRSA) strains with reference to there MIC. CDC method was found to be the most appropriate screening methodology for detection of VISA or VRSA for diagnostic laboratories