Gold nanoparticle colorants as traditional ceramic glaze alternatives

Historically, Roman stained glass has been a standard for high‐temperature color stability since biblical times but was not properly characterized as emission from nanoparticle plasmon resonance until the 1990s. The methods under which it was created have been lost, but some efforts have recently been made to recreate these properties using gold nanoparticle inks on glassy surfaces. This body of work employs gold nanoparticle systems ranging from 0.015% to 0.100% (wt/wt), suspended in a clear glaze body. The glazes are fired with traditional ceramic methods—in both gas reduction and electric oxidation kilns—in which nanoparticles are retained and can be imaged via TEM. Various colors intensities are reported in addition to changes in nanoparticle size after application and firing. The nanoparticle glazes are compared to traditional red glazes, highlighting the significantly lower metal loading required (5%‐10% for traditional glazes vs 0.100% for gold (wt/wt)), therein. Finally, proof of concept is provided with a functional gold nanoparticle mug, fired in reduction, that costs roughly 0.98$ USD in gold used.     

The Limitations of Public Housing: Relocation Choices in a Working-Class Community

Public housing is regarded as a map resource for rehousing families displaced by the urban renewal and highway programs. Yet a study of some 500 families relocated from Boston's West End reveals that the overwhelming majority refused to consider the possibility of living in a housing project, for reasons consistent with their preference for the residential patterns and life-styles prevalent in their former neighborhood. Those who do relocate in projects are not typical of the stable working class, and most frequently are characterized by some personal situation that limits their rehousing choice. Planners are confronted with the alternative of allowing public housing to become a care-taking institution for the disabled elements of the society, or of creating new forms for the public housing subsidy to encourage mobility, to provide satisfactory living environments consistent with the values of the inhabitants, and to permit the kinds of heterogeneity which prevail in existing neighborhoods.     

Comment on “Neighborhood Revitalization and Displacement: A Review of the Evidence”

The issue of neighborhood revitalization and displacement certainly does have a déjà vu quality to it. While government officials, academic housing analysts, and even neighborhood groups seem to approach the problem as if it were a brand new phenomenon, in reality the recent history of displacement under urban renewal, the interstate highway system, and other government programs is very relevant. What is remarkable in the spate of literature that recently has emerged on the issue—of which Sumka's article is quite representative—is the failure to acknowledge that history and the lessons it might offer.     

Driving on Mars with RSVP

The rover sequencing and visualization program (RSVP) suite of tools has been a critical factor in the success of the Mars exploration rover (MER) missions. It would be impossible to prepare the large command loads each sol without the capabilities that it possesses. It has proven to be robust and easy to use and capable of answering key questions about sequence validity and constraints. Certainly, training is required to use RSVP, but this is primarily in the general area of command sequencing and rover operations. Once these concepts are understood, RSVP feels natural for building sequences. RSVP has met its prime requirements of supporting rapid assimilation and understanding of the terrain and operational constraints, rapid sequence generation and validation, and production of documentation and archival products. This can be seen in the very limited number of sols lost due to errors in the command sequences. The success of the MER mission and the tremendous amount of science data collected attest to the capability of RSVP.     

Training feed-forward neural networks with gain constraints

Inaccurate input-output gains (partial derivatives of outputs with respect to inputs) are common in neural network models when input variables are correlated or when data are incomplete or inaccurate. Accurate gains are essential for optimization, control, and other purposes. We develop and explore a method for training feedforward neural networks subject to inequality or equality-bound constraints on the gains of the learned mapping. Gain constraints are implemented as penalty terms added to the objective function, and training is done using gradient descent. Adaptive and robust procedures are devised for balancing the relative strengths of the various terms in the objective function, which is essential when the constraints are inconsistent with the data. The approach has the virtue that the model domain of validity can be extended via extrapolation training, which can dramatically improve generalization. The algorithm is demonstrated here on artificial and real-world problems with very good results and has been advantageously applied to dozens of models currently in commercial use.     

The advanced set-up and control system for Dofasco's tandem coldmill

The new coupled pickle line and cold mill (CPCM) has been processing steel since December 1991 at Dofasco Inc. in Hamilton, Ontario, Canada. This mill rolls both sheet and tin plate. The work rolls for the last stand are often textured by grit blasting to roll “matte” finished strip. A new computer-targeted control system was developed for the roll speeds and gaps, specifically for matte rolling. The new set-up system uses Stone's model, which is more appropriate for the limited reductions evident with the rougher rolls. Conventional automatic gauge control (AGC) systems using thickness measurements after the last stand are limited in performance by the effect of long transport delays. These limitations are particularly critical during mill acceleration and deceleration. The use of a thickness gauge before the stand with matte rolls allows the development of AGC systems using shorter control loops for final gauge control. The AGC system uses a Smith predictor for transport lag, (phase shift), and compensation. The combination of the shorter AGC loop and the Smith predictor allows higher gains to be used in the control system. This set-up and control system has contributed to Dofasco's position as a market leader in thickness performance     

Device characteristics of (Al,Ga)As lasers with Ga(As,Sb) active layers

Device characteristics of double heterostructure lasers with Al0.4Ga0.6As confinement layers and GaAs0.99Sb0.01active layers are presented. Average emission wavelengths have been increased from 0.87 μm for undoped active layers to 0.88 μm for2 times 10^{17}cm^-3Ge doped active layers with a "wash" melt preceding the growth of the active layer and to 0.89 μ for1 times 10^{18}cm^-3Mg doped active layers grown following a "wash" melt. Threshold currents for lasers from 21 wafers are examined for several growth conditions and compared with Al0.08Ga0.92As active layer devices. Device resistance, external quantum efficiency, device degradation, and pulsed and CW threshold currents as a function of temperature are also discussed.