Behavior of Polar Compounds in Lubricating-Oil Films

The effect of oil films was investigated under comparatively mild conditions of boundary lubrication (up to 10 MPa) using electrical methods.

For a dynamic investigation, a pin-on-disk-type friction apparatus was uses. The capability of oil films for preventing metal-metal contact was estimated by measuring the contact resistance of the mating surfaces. For a static investigation, the characteristics of oil films while being squeezed from a very narrow slit between mercury and steel surfaces was observed by measuring the capacitance and conductance of oil films.

Squalane was used as a base oil. Saturated straight chain carboxylic acids (C₆-C₁₈), and methylesters and alcohols which had the corresponding chains to the acids were used as additives.

The following were found for the capability of oil films for preventing metal contact:

1) Prevention depended on the concentration of the additives (5—20 mol·m^-3), and increased with the increase of the concentration.

2) Prevention did not necessarily correspond to the adsorptivity of the polar groups of the additive molecule.

3) A chain-matching effect was observed with the compounds having a C₁₀ Chain-length which was not the same as that of the base oil molecule.

From the above results, it is concluded that the oil film must have a structural property, and its load-bearing capability for preventing metal-metal contact depends not only on the absorbed film but also on its structural property.     

Evaluation of region-specific residential energy systems for GHG reductions: Case studies in Canadian cities

This study estimates energy use and greenhouse gas (GHG) emissions associated with operations of alternative residential energy systems. In case studies, the same detached four-bedroom house built in accordance with R2000 standards is studied in five Canadian cities with different climate and electricity mix. Conventional energy systems and alternatives using three technologies, namely ground source heat pumps (GSHPs), photovoltaics, and energy-efficient appliances; and their combinations are investigated. The results show that using a GSHP in Calgary may increase overall GHG emissions, as electricity to drive the pump is primarily produced in coal-fired power stations. Using photovoltaics to generate electricity from carbon-free sources or energy-efficient appliances to reduce electricity demands result in almost no GHG reductions in Montreal and Vancouver, where over 90% of electricity comes from hydro power. The results also show that the use of photovoltaics in combination with GSHPs in Ottawa and Toronto, or with energy-efficient appliances in Calgary, can lead to more GHG reductions, compared to the use of a single technology. As a result, while climate affects energy use to some degree, local sources of electricity may have a greater impact on overall GHG emissions, which is an important measure of environmental impacts.     

Blends of thermoplastic polyurethane and polypropylene. II. Thermal and morphological behavior

Neat thermoplastic polyurethane (TPU), polypropylene (PP), and TPU/PP blends with different weight ratios that were prepared in a twin‐screw extruder were investigated with differential scanning calorimetry and light and scanning electron microscopy. The results confirmed PP matrix to TPU matrix phase inversion in the concentration region between 60/40 and 80/20 TPU/PP blends. The total degree of crystallinity of the blends and the crystallization temperature of PP decreased with increasing TPU content. On the other hand, the addition of elastomeric TPU to PP significantly increased the spherulite size of PP. The TPU melt islands in the PP matrix prolonged the crystallization of PP during solidification, and this enhanced the growth of spherulites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel copolymers of styrene. 1. Alkyl ring-substituted 2-cyano-3-phenyl 2-propenamides

Novel electrophilic trisubstituted ethylene monomers, alkyl ring-substituted 2-cyano-3-phenyl-2-propenamides, RC₆H₄CH=C(CN)CONH₂ (where R is 2-methyl, 3-methyl, 4-methyl, 4-ethyl, 4-i-propyl, 4-i-butyl, and 4-t-butyl), were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, AIBN at 70 °C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H- and ¹³C-NMR, GPC, DSC, and TGA. High T _g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500 °C range with residue (5–7 wt%), which then decomposed in the 500–800 °C range.     

Isolation of Multipotent Nestin-Expressing Stem Cells Derived from the Epidermis of Elderly Humans and TAT-VHL Peptide-Mediated Neuronal Differentiation of These Cells

A specialized population of cells residing in the hair follicle is quiescent but shows pluripotency for differentiating into epithelial-mesenchymal lineage cells. Therefore, such cells are hoped to be useful as implantable donor cells for regenerative therapy. Recently, it was reported that intracellular delivery of TAT-VHL peptide induces neuronal differentiation of skin-derived precursors. In the present study, we successfully isolated multipotent stem cells derived from the epidermis of elderly humans, characterized these cells as being capable of sphere formation and strong expression of nestin, fibronectin, and CD34 but not of keratin 15, and identified the niche of these cells as being the outer root sheath of the hair follicles. In addition, we showed that TAT-VHL peptide induced their neuronal differentiation in vitro, and confirmed by fluorescence immunohistochemistry the neuronal differentiation of such peptide-treated cells implanted into rodent brains. These multipotent nestin-expressing stem cells derived from human epidermis are easily accessible and should be useful as donor cells for neuronal regenerative cell therapy.     

Spin gap in Tl2Ru2O7 and the possible formation of Haldane chains in three-dimensional crystals

Dimensionality is one of the most important parameters of physical phenomena. Only two things determine the universality class of a phase transition: the dimensionality of a given system and the symmetry of the order parameter. In most cases, the dimensionality of a substance is predetermined by its crystal structure. Examples in which the effective dimensionality is reduced are quite rare. Here we show that the three-dimensional cubic system of Tl(2)Ru(2)O(7) most probably evolves into a one-dimensional spin-one Haldane system with a spin gap below 120 K, accompanied by anomalies in the structure, resistivity and susceptibility. We argue that these anomalies are due to an orbital ordering of Ru 4d electrons, with a strong coupling among three degrees of freedom: orbital, spin and lattice. Our work provides a unique example of the spontaneous formation of Haldane system with an insight into the intriguing interplay of different degrees of freedom.     

Fabrication and lithium intercalation properties of epitaxial Li2RuO3 thin films

Lithium intercalation in a lithium excess layered material Li₂RuO₃ was investigated using two-dimensional model electrodes with a restricted reaction plane of (002). Li₂RuO₃ films were synthesized on Al₂O₃(0001) substrate by a pulsed laser deposition, and X-ray diffraction measurements confirmed epitaxial growth of Li₂RuO₃(002). Electrochemical characterization using cyclic voltammetry and charge/discharge measurements indicated electrochemical reactions with a discharge capacity of 200 mAh g^− 1 for the film deposited at 400 °C followed by post-annealing at 550 °C. The electrochemical activity on the (002) plane indicated three-dimensional lithium diffusion in the two-dimensional layered rocksalt structure through the lithium sites in the transition metal layer.     

Highly polarized single-c-domain single-crystal Pb(Mn,Nb)O(3)-PZT thin films

In-plane unstrained single-c-domain/single-crystal thin films of PZT-based ternary ferroelectric perovskite, ξPb(Mn,Nb)O3-(1 - ξ)PZT, were grown on SrRuO(3)/Pt/MgO substrates using magnetron sputtering followed by quenching. The sputtered unstrained thin films exhibit unique ferroelectric properties: high coercive field, Ec > 180 kV/cm, large remanent polarization, P(r) = 100 μC/cm(2), small relative dielectric constants, ε* = 100 to 150, high Curie temperature, Tc = ~600 °C, and bulk-like large transverse piezoelectric constants, e31,f = -12.0 C/m(2) for PZT(48/52) at ξ = 0.06. The unstrained thin films are an ideal structure to extract the bulk ferroelectric properties. Their micro-structures and ferroelectric properties are discussed in relation to the potential applications for piezoelectric MEMS.