Phase morphology of as-molded and annealed blends of polyarylate/copolyester

The phase morphology of injection molded blends of polyarylate (PAR) and a copolyester (PCTG-5445) was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The use of ultramicrotomy to prepare ? 50 nm thin section TEM specimens and solvent etching to dissolve the PAR phase revealed PCTG as the matrix phase in the as-molded state which crystallized into PCTG spherulites upon annealing. The most consistent morphological information vs. concentration of PCTG and the highest structural integrity of the PCTG spherulites was obtained from thin sections treated with a mixture of 75% methylene chloride as the solvent for the PAR and 25% 2-propanol as the nonreactive diluent. XRD results from the annealed PCTG/PAR blends show crystalline reflections of 0.59, 0.53, 0.46, 0.38, and 0.35 nm, which disappear into the amorphous background below 50% PCTG.     

Influence of Stress and Chemical Homogeneity on Dielectric Properties of BaTi0.9Zr0.1O3

The influence of mechanical stress and chemical homogeneity on the permittivity of BaTi_0.9Zr_0.1O₃ ceramics prepared from mixed-oxide and hydrothermal powders was studied. To reduce stress, liquid-phase sintering was applied in conjunction with a low heating rate to stimulate the formation of large grains. The influence of chemical homogeneity was studied by variations in sintering temperatures and times. For both types of ceramics, the dielectric constant at the Curie temperature was influenced by both factors, but to a different extent. In the mixed oxide ceramic, chemical homogeneity played a more prominent role, while internal stress appeared to exert a larger influence in the hydrothermal ceramics. The dielectric constant at the Curie temperature could be increased by 5%–10% by an annealing treatment at 200°C, followed by slow cooling.     

XPS analysis of wet chemical etching of GaAs(110) by Br2–H2O: comparison of emersion and model experiments

We have applied photoelectron spectroscopy to investigate the surface composition after different surface treatments involving Br₂–H₂O mixtures in order to study wet chemical etching. Emersion experiments from Br₂–H₂O solution are compared with model experiments, in which Br₂–H₂O adsorbate and coadsorbate mixtures react with clean GaAs(110) surfaces. Our results indicate that Ga- and As-bromides formed initially are hydrolyzed to form the respective oxides. Without addition of Br₂, only slight oxidation of the surface takes place. There is an enrichment of Ga due to loss of As both in adsorption as well as in emersion experiments. Since in emersion experiments only a final situation is analyzed, the relative influence of surface reactivity and subsequent solvation effects cannot be distinguished easily, while model experiments give clear information on reaction products formed intermediately. However, model experiments differ in environment and temperature from the real solid–liquid interface. The presented results demonstrate that a combination of emersion and model experiments provide valuable insight into the mechanism of wet chemical etching on a microscopic level.     

Deep HDS over NiMo/Zr-SBA-15 catalysts with varying MoO3 loading

In the present work, with the aim of searching for new, highly effective catalysts for deep HDS, a series of NiMo catalysts with different MoO₃ loadings (6–30 wt.%) was prepared using SBA-15 material covered with ZrO₂-monolayer as a support. Prepared catalysts were characterized by N₂ physisorption, small- and wide-angle XRD, UV–vis diffuse reflectance spectroscopy, temperature-programmed reduction, SEM-EDX and HRTEM, and their catalytic activity was evaluated in the 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS). It was observed that ZrO₂ incorporation on the SBA-15 surface improves the dispersion of the Ni-promoted oxidic and sulfided Mo species, which were found to be highly dispersed, up to 18 wt.% of MoO₃ loading. Further increase in metal charge resulted in the formation of MoO₃ crystalline phase and an increase in the stacking degree of the MoS₂ particles. All NiMo catalysts supported on ZrO₂-modified SBA-15 material showed high activity in HDS of 4,6-DMDBT. The best catalyst having 18 wt.% MoO₃ and 4.5 wt.% NiO was almost twice more active than the reference NiMo/γ-Al₂O₃ catalyst. High activity of NiMo/Zr-SBA-15 catalysts and its evolution with metal loading was related to the morphological characteristics of the MoS₂ active phase determined by HRTEM.     

The Electrodeposition of Chromium from Tervalent Chromium Salt Solutions. Part I. Chromium Chloride and Chromium Sulphate Baths

The “imponderables” which affect the framework within which the Plating Shop must be planned are listed. The grouping of vats, cleaners and rinses are discussed and alternative methods of hand operation of plating vats described. The importance of depth of plating vats is stressed and various methods of constructing floors, drainage and vat supports are briefly indicated. Layouts for barrel plating shops both with inclined and horizontal barrels are suggested, and the importance of correct housing for electrical and other ancillary plant is emphasised.     

Sugar-based surfactants for consumer products and technical applications

Sugar-based surfactants, such as sorbitan esters, sucrose esters, alkyl polyglycosides, and fatty acid glucamides gain increasing attention due to advantages with regard to performance, health of consumers, and environmental compatibility compared to some standard products. Sorbitan esters are well established products, which are mainly used as leather and textile auxiliaries or as emulsifiers for food at a volume of approx. 20,000 t/a. Sucrose esters are relatively hydrophobic products. The actual market size is estimated to be < 4,000 t/a – the main application being emulsifiers for food and cosmetics. Their use is still limited. Alkyl polyglycosides and fatty acid glucamides represent a perfect amphiphilic structure with excellent surface activity as well as solubility due to highly selective syntheses. For alkyl polyglycosides industrial processes have been developed in the past couple of years and a total capacity of ca. 80,000 t/a has been established. They are mainly used for cosmetic, manual dishwashing, and detergent applications. Fatty acid glucamides to date are exclusively used by one company in liquid and powdered detergents. The estimated production capacity is approx. 40,000 t/a. Comparable in their performance profile as co-surfactants, both products differ in their raw material base: whereas in the case of the fatty acid glucamides methylamine is incorporated in the product, alkyl polyglycosides are completely based on renewable resources. This, combined with very good performance and mildness, could be one reason why alkyl polyglycosides are the most successful sugar-based surfactants nowadays. Research to develop derivatives on this basis is still ongoing.     

全面测试技术

Uster Tester 5-S800是纱线质量控制系统,有许多的测试选择项,可靠准确的性能,测试速度达800m／min,与Uster Quantum测试系统的在线测试能力一起,该装置可以得到闭环的纱线质量保证。现在,纱线可进行全数测试并且可进行质量的完全控制。     

Variability of particle number emissions from diesel and hybrid diesel-electric buses in real driving conditions

A linear mixed model was developed to quantify the variability of particle number emissions from transit buses tested in real-world driving conditions. Two conventional diesel buses and two hybrid diesel-electric buses were tested throughout 2004 under different aftertreatments, fuels, drivers, and bus routes. The mixed model controlled the confounding influence of factors inherent to on-board testing. Statistical tests showed that particle number emissions varied significantly according to the after treatment, bus route, driver, bus type, and daily temperature, with only minor variability attributable to differences between fuel types. The daily setup and operation of the sampling equipment (electrical low pressure impactor) and mini-dilution system contributed to 30-84% of the total random variability of particle measurements among tests with diesel oxidation catalysts. By controlling for the sampling day variability, the model better defined the differences in particle emissions among bus routes. In contrast, the low particle number emissions measured with diesel particle filters (decreased by over 99%) did not vary according to operating conditions or bus type but did vary substantially with ambient temperature.     

Mapping woody-biomass supply costs using forest inventory and competing industry data

The goals of energy independence and sustainability have motivated many countries to consider biomass-based energy sources. The United States has substantial and increasing forest resources that could be used to produce both electricity and liquid fuel. However, these forest resources are highly heterogeneous in terms of the wood’s properties, the logging cost, the spatial distribution, and the value to other industries. These factors make predicting costs and selecting plant locations particularly challenging. When dealing with forest biomass, feedstock cost and location have frequently been highly simplified in previous studies. This paper presents a methodology for combining highly resolved forest inventory and price data with records of competing industries to develop detailed maps of feedstock availability. The feedstock sourcing strategy of the proposed bioenergy plants is modeled by a cost-minimizing linear program, as is the feedstock selection of the competing mills. A case study is performed on the southeast United States.