Molecular correlations in sheared thermotropic copolyesters showing banded textures

Banded textures produced in a thermotropic liquid crystal polymer by shearing between glass slides are examined by using both transmission electron and polarized light microscopy. The periodic variation in director orientation about the shear axis, as measured by light microscopy, is shown to be distinctly different from that indicated by electron diffraction. Measurements of birefringence and observation of Zernicke phase contrast indicate periodic variations in optical properties of the polymer, in step with the bands. Such effects are accounted for in terms of a synchronous rotation of the planar aromatic groups about the molecular chain axes. Evidence for an out-of-plane component of molecular orientation is also presented.     

Evaluating hyperspectral imaging of wetland vegetation as a tool for detecting estuarine nutrient enrichment

Nutrient enrichment and eutrophication are major concerns in many estuarine and wetland ecosystems, and the need is urgent for fast, efficient, and synoptic ways to detect and monitor nutrients in wetlands and other coastal systems across multiple spatial and temporal scales. We integrated three approaches in a multi-disciplinary evaluation of the potential for using hyperspectral imaging as a tool to assess nutrient enrichment and vegetation responses in tidal wetlands. For hyperspectral imaging to be an effective tool, spectral signatures must vary in ways correlated with water nutrient content either directly, or indirectly via such proxies as vegetation responses to elevated nitrogen. Working in Elkhorn Slough, central California, where intensive farming practices generate considerable runoff of fertilizers and pesticides, we looked first for long- and short-term trends among temporally ephemeral point data for nutrients and other water quality characters collected monthly at 18 water sampling stations since 1988. Second, we assessed responses of the dominant wetland plant, Salicornia virginica (common pickleweed) to two fertilizer regimes in 0.25 m² experimental plots, and measured changes in tissue composition (C, H, N), biomass, and spectral responses at leaf and at canopy scales. Third, we used HyMap hyperspectral imagery (126 bands; 15–19 nm spectral resolution; 2.5 m spatial resolution) for a synoptic assessment of the entire wetland ecosystem of Elkhorn Slough. We mapped monospecific Salicornia patches (～ 56–500 m²) on the ground adjacent to the 18 regular water sampling sites, and then located these patches in the hyperspectral imagery to correlate long-term responses of larger patches to water nutrient regimes. These were used as standards for correlating plant canopy spectral responses with nitrogen variation described by the water sampling program. There were consistent positive relationships between nitrogen levels and plant responses in both the field experiment and the landscape analyses. Two spectral indices, the Photochemical Reflectance Index (PRI) and Derivative Chlorophyll Index (DCI), were correlated significantly with water nutrients. We conclude that hyperspectral imagery can be used to detect nutrient enrichment across three spatial and at least two temporal scales, and suggest that more quantitative information could be extracted with further research and a greater understanding of physiological and physical mechanisms linking water chemistry, plant properties and spectral imaging characteristics.     

The Effects of Cyclic Terminal Groups in 4-Aminoazo-benzene and Related Azo Dyes: Part 21—pKa Values of Some Monoazo Dyes Derived from

Basicity values have been determined for series of monoazo dyes incorporating a pyrrolidino or a piperidino moiety. In general, the pK_a value is found to decrease as the donor capacity of the terminal nitrogen atom decreases.The basicities of the 4'-substituted piperidinoazobenzenes decrease as the electron withdrawing strength of the 4'-substituent increases. However, the pK_a values of the related pyrrolidino compounds appear to be insensitive to the substituent.     

The morphology of rigid-rod polymers and molecular composites resulting from coagulation processing

The effects of processing conditions on the morphology of molecular composite films are examined by optical and electron microscopy. During coagulation processing from solutions in methanesulfonic acid (MSA), rigid-rod polymer, such as poly(p-phenylenebenzobisoxazole) (PBO), phase separates into undesirable aggregates. The coagulant and the method of its introduction have been found to exert a strong impact on the final film morphology. A quench of a PBO solution in MSA into a water bath results in a three dimensional interconnected network of PBO, while a slower introduction of water results in a more amorphous material. A computer simulation program of the coagulation process has been developed to better understand the different structures emerging from coagulation processing of molecular composites. The simulation results are in qualitative agreement with the experimental observations.     

V. Yeast sequencing reports. Identification of a gene encoding a new Ypt/Rab-like monomeric G-protein in Saccharomyces cerevisiae

A Saccharomyces cerevisiae sequence cloned by serendipity was found to encode a protein that is a new member of the Ypt/Rab monomeric G-protein family. This sequence shows high homology to the yeast genes SEC4 and YPT1 and, like SEC4 and YPT1, is essential for viability. The sequence was localized to chromosome V based upon hybridization to pulse-field gel-separated yeast chromosomes. The sequence has been deposited in the GenBank data library under Accession Number L17070.     

Pareto multi-criteria decision making

The paper concerns design governed by multiple objective criteria, which are conflicting in the sense of competing for common resources to achieve variously different performance objectives (financial, functional, environmental, esthetical, etc.). A multi-criteria decision making (MCDM) strategy is proposed that employs a tradeoff-analysis technique to identify compromise designs for which the competing criteria are mutually satisfied in a Pareto-optimal sense. The MCDM strategy is initially developed for the case of design governed by n = 2 objective criteria. It is then extended to design governed by n > 2 objective criteria, by introducing the concept of primary and aggregate criteria. It is proved that, from among the theoretically infinite number of feasible designs forming the Pareto front for a design problem governed by n independent objective criteria, there exists a unique Pareto-compromise design that represents a mutually agreeable tradeoff between all n criteria. This remarkable result is illustrated for a flexural plate design governed by n = 2 criteria, a bridge maintenance-intervention protocol design governed by n = 3 criteria, and a media centre envelop design governed by n = 11 criteria.     

Evaluation of capital cost data. part 7: Liquid waste disposal with emphasis on physical treatment

Capital cost correlations are given for oil-water separators, equalization basins, primary clarifiers, clarifiers and clarifier mechanisms, reverse osmosis unit, ultrafiltration units, gravity filters and miroscreens. Data are included for raw sewage, intermediate and recirculation pumping stations and for preliminary treatment (or bar screens, grit removal, overflow and bypass chamber and Parshall flume), for grit removal, comminution and gas stripping. The correlations are accurate to ± 30%, expressed in Canadian dollars and adjusted to a Marshall and Swift value of 1000. Details as to what components are included in the cost are given. Data are given for the labour and material costs to create a working process module. For inflation indices, a critique of the Engineering News Record, EPA small city, Marshall and Swift, Chemical Engineering and Southam inflation indices suggested that the Marshall and Swift index is most appropriate for the construction and process equipment studied here. Concerning the currency exchange, for the equipment and processes in this study, equipment costs the same whether expressed directly in US or Canadian dollars. To put the current data into perspective, several hundred sources of cost data were analyzed. The major correlations are compared, on a consistent basis, with current data.     

High-Performance Multilayer Capacitor Dielectrics from Chemically Prepared Powders

Advantages of chemically prepared powders for electronic ceramics have been demonstrated for a number of multilayer capacitor (MLC) dielectrics. A cost-efficient precipitation process was developed to produce undoped or doped crystalline barium titanate powder with a narrow particle size distribution close to 0.5 μm. More complex compositions, e.g., barium-neodymium titanate, were amorphous as precipitated but could be crystallized by calcination below 1000°C. Additional compositional modifications, to adjust electrical properties or to lower sintering temperature, were accomplished by doping the surface of the powder particles using a solution coating process. Exceptional fired densities and electrical performance were obtained.