Fabrication and evaluation of solid-oxide fuel cell anodes employing reaction-sintered yttria-stabilized zirconia

This paper reports on the fabrication and performance of solid-oxide fuel cell (SOFC) anodes utilizing yttria reaction-sintered zirconia (YRSZ). Through the reaction-sintering process, the technical-grade YSZ commonly used in the Ni-YSZ anode cermet is replaced with lower-cost ZrO₂ and Y₂O₃ materials. When sintered in the presence of nickel oxide, ZrO₂ and Y₂O₃ form cubic-phase YSZ at temperatures characteristic of SOFC processing (1400-1550 °C). Reaction sintering enables the formation of YSZ during cell fabrication, reducing SOFC anode raw-materials cost and the number of SOFC-fabrication processes. This paper reports the results of a broad range of characterization and performance measurements to evaluate the YRSZ material, including (1) crystal structure, (2) morphology, (3) pore-size distribution, (4) electronic resistivity, (5) fracture strength, (6) gas transport and catalytic activity, and (7) electrochemical performance. Material properties and performance are found to be comparable to or better than equivalent materials fabricated by conventional processes.     

Electrical characterization of HfO2 films obtained by UV assisted injection MOCVD

HfO₂ films were deposited at low temperature (400 °C) by UV assisted injection metal-organic chemical vapor deposition (UVI-MOCVD). A three-step process was used for this study, consisting of (A) Pre-deposition anneal for nitridation; (B) Deposition step; (C) Post-deposition annealing in oxygen. Special attention was paid to the effect of UV exposure during these steps. Films were characterized by physical, optical and electrical techniques. Thickness was determined by different methods (X-ray Reflectrometry (XRR), spectroscopic ellipsometry and transmission electron microscopy) and a good agreement was found for all samples. The HfO₂ permittivity, equivalent oxide thickness (E_OT), flat-band voltage (V_fb) and total charge (Q_t) were extracted from the CV response at high frequency taking into account the HfO₂ and SiO₂ thicknesses obtained by XRR. The calculated permittivity values were in the range 7–13, i.e. lower than theoretical values for the monoclinic phase. Explanations are suggested in the context of the other characterizations. JE_eff characteristics were constructed taking into account the E_OT values (E_eff = V/E_OT). Effective breakdown fields range between 8.7 and 16.9 MV/cm. No dependence of E_eff with UV exposure was found.     

SELENIUM BLACK GLASS*

A black glass was made by melting a soda-lime-silica glass under a reducing atmosphere with the addition of 0.6% of selenium and 0.1% of cobalt carbonate, CoCO_s. The light absorption of a specimen about 0.01 inch thick in the range of 400 to 750 mp was superior to that of commercial black glass. The maximum transmission was 27% at 750 mp. The use of nickel and iron oxides is less effective than cobalt oxide for obtaining selenium black glass.     

Warm homes: Drivers of the demand for heating in the residential sector in New Zealand

New Zealand houses are large, often poorly constructed and heated, by OECD standards, and consequently are colder and damper indoors than recommended by the World Health Organisation. This affects both the energy consumption and the health of households. The traditional New Zealand household pattern of only heating one room of the house has been unchanged for decades, although there has been substantial market penetration of unflued gas heaters and more recently heat pumps. This paper describes the residential sector and the results of two community-based trials of housing and heating interventions that have been designed to measure the impact of (1) retrofitting insulation and (2) replacing unflued gas heaters and electric resistance heaters with heat pumps, wood pellet burners and flued gas heaters. The paper describes findings on the rebound effect or ‘take-back’—the extent to which households take the gains from insulation and heating improvements as comfort (higher temperatures) rather than energy savings, and compares energy-saving patterns with those suggested by an earlier study. Findings on these aspects of household space heating are discussed in the context of the New Zealand government's policy drive for a more sustainable energy system, and the implications for climate change policy.     

Core-Edge design of storage area networks—A Single-edge formulation with problem-specific cuts

Optimization and heuristic methods for the design of medium to large storage area networks (SANs) are in the early stages of development, but are required if large clustered storage systems are to become a viable alternative to expensive monolithic storage. We present here a new mixed-integer formulation for optimal design of a storage area network. Our formulation models the Single-edge Core-Edge topology. Using a testbed of medium to large problems, we compare the solution times for our new formulation to the current benchmark in the literature—our formulation solves in significantly less time with an off-the-shelf optimization software package. We also generate problem-specific cuts to further reduce the solution time for our formulation. An algorithm, which includes an integer programming subproblem, is described for generating some of these cuts. For all test problems, the cuts yield a further reduction in the solution time.     

Flavouring of imitation cheese with enzyme-modified cheeses (EMCs): Sensory impact and measurement of aroma active short chain fatty acids (SCFAs)

Enzyme-modified cheeses (EMCs) are used to impart flavour to imitation cheese products. Cheeses (pH 6 or 5.5) were formulated with 5% w/w EMC, having low, medium or high levels of lipolysis and were examined by a sensory panel. Free fatty acid analyses were performed using SPME/GC. The flavour profile of the flavoured cheeses was affected by EMC composition and pH of the cheese base. Cheeses at a pH of 6.0, flavoured with low lipolysis EMCs, were described as ‘bland’. Lowering the pH of the cheese matrix to 5.5 appeared to increase the flavour intensity of the cheese flavoured with low lipolysis EMC and panellists ranked this cheese the highest, describing its flavour as ‘well-balanced and ‘cheesy’. This study shows that the flavours of imitation cheeses are influenced by the level of lipolysis of the EMCs used to flavour them and also by the pH of the cheese base.     

Use of magnetically-saturated regions in remote field eddy current tools

The remote field eddy current (RFEC) technique is of potential interest for inspecting pipelines for stress corrosion cracking. Magnetic saturation techniques would allow higher operating frequencies and scanning speeds to be used. The use of selectively-saturated regions (windows) near the exciter and detector offers additional advantages. Finite element, analytic, and experimental measurements are presented in this paper. They show that, while saturation techniques are helpful, the effects are less than initially estimated from simple skin depth approximations.     

Relation between catastrophizing and depression in chronic pain patients.

The relation between catastrophizing, depression, and pain was examined in 125 chronic pain patients. The Coping Strategies Questionnaire (CSQ) developed by A. K. Rosenstiel and F. J. Keefe (see record 1984-18170-001) assessed patients' use of cognitive and behavioral strategies to cope with chronic pain. A significant association between catastrophizing and depression was found. In order to address questions of measurement redundancy, 6 clinical psychologists rated the degree to which items on the CSQ reflected depressive symptomatology. All items contained in the Catastrophizing subscale were rated by all psychologists as being reflective of symptoms of depression and were removed from the CSQ. When this subscale was excluded, none of the remaining CSQ subscales were significantly related to depression. The discussion addresses the interpretive difficulties that arise from hypothesizing mediating relations between variables that are conceptually and operationally confounded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)