A High-Strain-Rate Alumina-Based Ceramic Composite

An alumina-based ceramic codispersed with zirconia and mullite was synthesized with a submicron grain size. At high temperatures, steady-state creep with very limited grain growth was achieved for samples with 40 vol% alumina, 30 vol% zirconia, and 30 vol% mullite (AZ30M30). Constant stress compressive creep behavior of AZ30M30 showed a stress exponent of 2 and an activation energy of 880 kJ/mol. A strain rate of 0.01 s⁻¹ was obtained for AZ30M30 at 60 MPa and 1500°C, indicating the potential for high-strain-rate superplasticity.     

Father contributions to cortisol responses in infancy and toddlerhood.

The current study is one of the first prospective examinations of longitudinal associations between observed father caregiving behaviors and child cortisol reactivity and regulation in response to emotional arousal. Observations of father and mother caregiving behaviors and child cortisol levels in response to challenges at 7 months and 24 months of child age were collected. Analyses were based on a subsample of children from the Family Life Project who lived with both their biological mothers and fathers and for whom there was at least partial cortisol data (7 months: n = 717; 24 months: n = 579). At the challenge conducted at 7 months of child age, 49.0% of the sample were girls; racial composition of the sample was 25.8% African American and 74.2% European American. At the challenge conducted at 24 months of child age 49.9% of the sample were girls; racial composition was 24.7% African American and 75.3% European American. We conducted analyses across assessment points simultaneously using mixed linear modeling for repeated measures data to test for differential effects of fathering across infancy and toddlerhood. Concurrent measures of father negativity were positively associated with greater increases in child cortisol levels in response to emotion challenge at 7 months (p = .01) and with higher overall levels of cortisol at 24 months (p     

Spray Drying Yogurt Incorporating Hydrocolloids: Structural Analysis, Acetaldehyde Content, Viable Bacteria, and Rheological Properties

Hydrocolloids and some of their mixtures were used to prepare spray-dried yogurt. Acetaldehyde retention and microbial viability were evaluated. Morphology was examined by scanning electron microscopy and the yield stress was evaluated, to assess the damage to the microstructure by the drying process. The yield stress displayed a significant irreversible decrease after spray drying and micrographs indicate that the microstructure of the yogurt was severely damaged by the drying process. Micrographs indicated that κ-carrageenan and κ-carrageenan-locust bean gum gave more protection to the casein matrix, leading to greater acetaldehyde retention (92% and 89%, respectively). Microbial viability was improved when pectin was used as the encapsulating agent.     

Restoration of DWI data using a Rician LMMSE estimator

This paper introduces and analyzes a linear minimum mean square error (LMMSE) estimator using a Rician noise model and its recursive version (RLMMSE) for the restoration of diffusion weighted images. A method to estimate the noise level based on local estimations of mean or variance is used to automatically parametrize the estimator. The restoration performance is evaluated using quality indexes and compared to alternative estimation schemes. The overall scheme is simple, robust, fast, and improves estimations. Filtering diffusion weighted magnetic resonance imaging (DW-MRI) with the proposed methodology leads to more accurate tensor estimations. Real and synthetic datasets are analyzed.      

A combined methanol autothermal steam reforming and PEM fuel cell pilot plant unit: Experimental and simulation studies

An integrated system for hydrogen production via autothermal steam reforming of methanol and consequent power generation in a polymer electrolyte membrane (PEM) fuel cell has been developed and operated at C.P.E.R.I. The pilot plant comprises an autothermal reforming reactor to produce hydrogen, a preferential oxidation reactor (PROX) to reduce CO concentration below 50 ppm and a PEM fuel cell for power generation.The present paper deals with the study of this system, both from an experimental and a theoretical point of view. The experimental work aims to: (a) examine the effect of the reforming temperature on methanol conversion and on the effluent stream concentration, (b) investigate the effect of reaction temperature and O₂/CO ratio on the performance of the PROX reactor, and (c) evaluate the operation of a 10-cell PEM fuel cell, using pure hydrogen and air at three temperature levels. The experimental data are subsequently utilized for the validation of one-dimensional pseudo-homogeneous models that have been developed for the two reactors and also for the identification of the voltage–current characteristic curve of the PEM fuel cell. The validated models are then used to investigate the behavior and explore the interactions, both static and dynamic, among the various process subsystems.     

Robert Moses and Lewis Mumford: competing paradigms of growth in Portland,Oregon

Portland boosters invited Lewis Mumford and Robert Moses to Portland to comment on the growth of the city and the region in the years surrounding World War II. Mumford emphasized regionalism and a dispersal of the population to new towns, which would be satellites to the central city, strengthened as a regional centre. Moses, coming to Portland just five years later than Mumford, stressed freeway, bridge and park development, with a mind toward girding the city for post-war growth. In the mid-century, Portlanders were more inclined to adopt Moses' suggestions, almost all of which were eventually implemented. A shift in political culture in the 1960s and 1970s, however, brought a renewed commitment to the ideals Mumford had espoused and, today, the Portland area's regional planning agency, Metro, has adopted a Regional Framework Plan that embraces the Mumfordian vision, with an almost blatant rejection of Moses' commitment to freeways, bridges and other types of massive investment in auto-accommodating infrastructure. This paper discusses the difference between the two paradigms of planning and provides some explanations for the shift in the Portland region from a Mosesian to a Mumfordian ideal.