Effect of mixing on melt flow properties of high-density polyethylene

An investigation has been made into the effect of mixing by a screw extruder upon the molecular characteristics and the melt flow properties of high-density polyethylene. The crosslinking between molecules predominates over the scission of a molecule at an early stage of mixing, but with further increase in the degree of mixing, this situation reverses itself to bring about the formation of branched polymers. Static flow and dynamic viscoelastic properties of molten high-density polyethylene change considerably with increase in the degree of mixing. The apparent viscosity drops rather sharply after mixing. The dynamic properties for the original resin show smaller frequency dependence of the viscosity and larger dependence of the rigidity than those for extrudates. The relaxation spectra become broader with increase in mixing. These may mainly be due to the change of the molecular characteristics of high-density polyethylene with mixing by an extruder.     

Solitary waves in saturated films of superfluid 4He

It is shown that there should exist in saturated films of superfluid ⁴He at low temperature a nonlinear surface wave described by the Korteweg-de Vries equation. The effect of surface tension makes the solitary wave cold, in contrast to very thin films discussed in a preceding paper. An electrostatic method is proposed to generate cold solitary waves. The asymptotic behavior can be found theoretically by the inverse scattering method. Estimates of parameters imply the possibility of observing each solitary wave separately.     

Multiobjective optimization of a two-piece aluminum beverage bottle considering tactile sensation of heat and embossing formability

This paper deals with a multiobjective optimization of a screw-top beverage bottle for hot vending. The bottle body has temperate touch feeling and can be embossed easily by axially imposing a cylindrical tube die with rib-shaped inner surface on the outer surface of the bottle body. Initially, a contact nonlinear analysis of fingers grasping the bottle is carried out, and the amount of heat transmitted from the hot bottle to the flesh of the finger is then calculated to evaluate the hot touch feeling. Meanwhile, the simulation of the rib-shape embossing process of the bottle body is performed to evaluate the embossing formability of different rib shape designs. Finally, using response surface approximation method and weighted sum approach, a multiobjective optimization on the shape of the rib is performed to obtain temperate touch feeling as well as better embossing formability. The amount of heat transmitted from the optimized rib-shape embossed bottle decreased at least 30% as compared with that of the regular bottle.     

Analysis of Human Oral Mucosa Ex Vivo for Fatty Acid Compositions Using Fourier-transform Infrared Spectroscopy

The purpose of this research was to develop an infrared spectroscopic technique (Fourier transform infrared spectroscopy with attenuated total reflectance system; FTIR-ATR) for non-invasive measurement of saturated and unsaturated fatty acid compositions in human oral mucosa obtained from three nationalities; Iranian, Vietnamese, and Indonesian. The histogram patterns of fatty acid compositions for three nationalities suggest that the pattern of unsaturated fatty acids were quite different, although the distribution profiles of fatty acid to lipid ratios in FTIR-ATR has a similar normal pattern with small difference in skewness and mode. The second derivative infrared spectra of the mucosal tissues in the wavenumber regions from 1,600 to 1,760 cm⁻¹ and 2,800 to 3,050 cm⁻¹ were analyzed with partial least squares (PLS) multivariate regression analysis method. With this analysis method we compared predicted values with the measured values of ten categorized fatty acid compositions, i.e., a(saturated C17 or lower), b(C16:1 + C17:1), c(C18:0), d(C18:1), e(C18:2), f(saturated C20 or longer), g(C20:3 + C20:4), h(C22:1 + C24:1), i(C22:6), j(γC18:3). Almost all fatty acid compositions of oral mucosa were well predicted with differences between predicted and measured values within ±5% of total, however, errors were relatively larger in minor components such as C22:6 than major components.     

Identification of a sex pheromone component of the geometrid moth <Emphasis Type="Italic">Milionia basalis pryeri</Emphasis>

A single component in extracts of virgin female Milionia basalis pryeri moths elicited responses from male moth antennae. This compound (ca. 7 ng/female) was identified as (Z,Z)-(3S,4R)-3,4-epoxynonadeca-6,9-diene by GC-MS and NMR analyses, microchemical reactions, and comparative chiral HPLC. In a field test, synthetic (Z,Z)-(3S,4R)-3,4-epoxynonadeca-6,9-diene attracted male moths.The opposite enantiomer, the racemic mixture, and virgin female moths held in small cages attracted no more moths than the solvent controls.     

Surface activities,biodegradability and antimicrobial properties of n-alkyl glucosides,mannosides and galactosides

n-Alkyl α-and β-glucopyranosides, α-D-mannopyranosides and β-D-galactopyranosides with alkyl chains having from 8 to 12 carbon atoms were synthesized and their surface properties-such as static surface tension (γ), critical micelle concentration (CMC), occupation area of molecule, dynamic surface tension and foaming properties, biodegradability and antimicrobial activities—were evaluated. Alkyl glycosides containing C8 to C12 carbon chains showed surface activities and critical micelle concentrations. D-Glucoside, D-mannoside and D-galactoside having the same alkyl chain showed similar surface tension lowering at CMC (γ_CMC) and occupation area of the molecule at the surface. Among the alkyl glucosides, α-anomers were less hydrophilic than β-anomers. All alkyl glycosides tested in this study were readily biodegraded by activated sludge of a municipal sewage plant compared to those of ethoxylated nonionic alcohols. The difference of the hydrophilic glycopyranoside group in biodegradability was not seen clearly. n-Alkyl glycosides containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. n-Dodecyl α-D-mannopyranoside was the most effective, the order of antimicrobial activity being mannopyranoside > glucopyranoside > galactopyranoside group. Members of this class of compounds exhibit the physicochemical and biological properties needed both for a wide range of applications and for environmental acceptance.