Degradation behaviour of polymeric materials found in auto Shredder residue wastes

The thermogravimetry of a series of 50/50 mixtures of polypropylene, acrylonitrile/butadiene/styrene, polyvinyl chloride and polyurethane polymers have been studied as representative of the major polymeric materials found in automobile shredder residues. The weight loss behaviour of these polymeric mixes have been compared with the results calculated from the individual polymeric components. This comparison of the thermogravimetry curves and the calculated kinetic parameters indicates that interactions occur between the individual polymers when heated together. The extent of these interactions are dependent upon the polymeric mixtures being considered, but in most cases the changes in the degradation kinetic parameters were not large. Issued as NRCC #35741     

Controlled deposition of structured polymer films: chemical and rheological factors in chitosan film formation

The technique of "spread coating" has been used to create thin films from solutions of deacetylated and butyl-modified chitosan polymer, and the effect of deposition rate on film thickness has been characterized. Results show that films of controlled thickness can be reproducibly produced and that hydrophobic modification of the polymer can extend the range over which a linear response between film thickness and deposition rate is achieved. Viscometry and fluorescence spectroscopy were also employed to characterize the micellar characteristics of solutions of both deacetylated and butyl-modified chitosan polymer. Although both deacetylated and butyl-modified chitosan solutions were found to have inter- and intramolecular interactions, as well as hydrophobic domains able to incorporate fluorophores, deacetylated chitosan was found to be more interconnected via intermolecular interactions at higher concentrations. These results are important as having the ability to understand how the introduction of hydrophobic modification, a technique shown to introduce solution-based micelle structure and micellar aggregates that support enzyme immobilization, affects film thickness and morphology of spread coated thin films will aid the long-term development and deployment of chitosan-based biofuel cell electrodes.     

Measurement of the Ratio of the Vibrational Raman Cross Section for H2O Vapor to the Nitrogen Vibrational-Rotational Raman Band

In this letter, measurements of the ratio of the v¹ Raman cross section for H²O vapor to the Nitrogen vibrational-rotational Raman band cross section are reported. These measurements, Involving as they do, the technique of laser atmospheric probing have cone about through methods not usually a part of the repertoire of the spectroscopist.     

Joint System Quantum Descriptions Arising from Local Quantumness

We study the entropy flux in the stationary state of a finite one-dimensional sample ${\mathcal{S}}$ connected at its left and right ends to two infinitely extended reservoirs ${\mathcal{R}_{l/r}}$ at distinct (inverse) temperatures ${\beta_{l/r}}$ and chemical potentials ${\mu_{l/r}}$ . The sample is a free lattice Fermi gas confined to a box [0, L] with energy operator ${h_{\mathcal{S}, L}= - \Delta + v}$ . The Landauer-Büttiker formula expresses the steady state entropy flux in the coupled system ${\mathcal{R}_l + \mathcal{S} + \mathcal{R}_r}$ in terms of scattering data. We study the behaviour of this steady state entropy flux in the limit ${L \to \infty}$ and relate persistence of transport to norm bounds on the transfer matrices of the limiting half-line Schrödinger operator ${h_\mathcal{S}}$ .     

螺旋波激发甲烷等离子体光谱诊断

利用螺旋波激发等离子体化学气相沉积(LPP-CVD)技术,以甲烷和氦气为反应气体产生等离子体.通过采集到甲烷的可见光到紫外发射光谱,对甲烷等离子体进行原位诊断,发现存在CH、Ha及Hβ等碎片粒子的光辐射,同时,分析了不同入射功率、气压下CH粒子以及Hβ、Hγ的相对强度变化情况.结果表明:CH粒子的相对强度随着射频功率是先增大而后减小,随工作气压的增大而逐渐减小;随气压及功率的增加,Hβ、Hγ相对强度变化的总体趋势都是先增加而后减小的.     

Effects of Arsenic Compounds on Proliferation and Nitric Oxide Synthesis in C3H 10T 1/2 Murine Fibroblasts

Exposure to arsenic, either through chronic consumption of contaminated water or inhalation, is associated with increased risk of cancer, yet the mechanism by which arsenicals promote neoplastic change remains undefined. The carcinogenic process involves the formation of heritable genetic changes in the DNA of normal cells and this process may be enhanced by environmental agents that increase cellular proliferation, increase DNA damage and decrease the ability to repair damage or cause immunosuppression. We describe the inhibition of cellular proliferation of C3H 10T1/2 murine fibroblasts in the presence of 1.0 μM arsenate or arsenite; yet cacodylic acid had no significant effect on cell growth in culture at this concentration. Both arsenate and cacodylate, at micromolar concentrations, slightly stimulated cell growth and cell density when cells were treated with interferon-γ/lipopolysaccharide (IFN-γ/LPS). At 1 μM , arsenate and cacodylate also slightly increased IFN-γ/LPS-induced nitric oxide (NO) synthesis in this cell line, consistent with the increase in cell number observed, whereas 1 μM arsenite significantly increased NO production on a per-cell basis. In contrast, arsenite significantly inhibited NO synthesis at concentrations above 10 μM arsenite as, to a lesser extent, did arsenate and cacodylate. These results suggest that ingestion of arsenicals could alter cellular generation of NO and interfere with its associated physiological functions. © 1997 by John Wiley & Sons, Ltd.     

Application of ultrasound to organic reactions: ultrasonic catalysis on hydrolysis of carboxylic acid esters

Irradiation with ultrasound was found to facilitate the two-phase basic hydrolysis of aromatic carboxylic acid esters.     

The use of thermal analysis to study thermal processing effects on polypropylene

The thermal stability of a polypropylene copolymer has been examined at several stages during the processing of the material into its final product in order to obtain information on the influence of processing steps such as grinding and thermal heating on the expected lifetime of the material. Mass loss kinetics in an inert atmosphere were able to detect differences in thermal stability, but oxidative differential scanning calorimetry studies proved to be a more sensitive techiique. A comparative study of a specially prepared series of samples revealed the importance of additives on measured thermal stability and indicated that both mechanical and thermal processing can cause reduction in measured thermal stability.