Fuel cell techno-personal milestones 1984–2006

This paper is based on my award acceptance talk on the occasion of receiving the Grove Medal for Fuel Cell Science and Technology, at the 2006 Grove meeting in Torino, Italy. I chose to name the talk: “Fuel Cell Techno-Personal Milestones 1984–2006”, trying to reflect on important milestones in the history of the science and technology of hydrogen/air and methanol/air polymer electrolyte fuel cells, in which I was fortunate to be involved for over 20 years.     

Statistical Analysis for Decision Making

In this article we consider a generalization of the univariate g-and-h distribution to the multivariate situation with the aim of providing a flexible family of multivariate distributions that incorporate skewness and kurtosis. The approach is to modify the underlying random variables and their quantiles, directly giving rise to a family of distributions in which the quantiles rather than the densities are the foci of attention. Using the ideas of multivariate quantiles, we show how to fit multivariate data to our multivariate g-and-h distribution. This provides a more flexible family than the skew-normal and skew-elliptical distributions when quantiles are of principal interest. Unlike those families, the distribution of quadratic forms from the multivariate g-and-h distribution depends on the underlying skewness. We illustrate our methods on Australian athletes data, as well as on some wind speed data from the northwest Pacific.     

Wave interactions and wave-structure scattering in nonlinear patterned waveguides

The nonlinear interactions between discrete optical solitons that propagate in different regimes of diffraction, and the nonlinear scattering of dispersive waves by local optical potentials, were studied experimentally. It is well known in electromagnetism that when linear coherent waves meet they interfere without interactions. Linear waves also scatter through local optical structures without exchanging any power with guided and anti-guided modes of these structures. When a focusing Kerr nonlinearity is present, linearly inhibited phenomena, which break these rules, are shown to exist. Our studies were performed with Silica glass and semiconductor AlGaAs nonlinear planar modulated waveguides, excited by ultra-short pulses in the near infrared spectral regime.     

Pem fuel cells for transportation and stationary power generation applications

We describe recent activities at Los Alamos National Laboratory devoted to polymer electrolyte fuel cells in the contexts of stationary power generation and transportation applications. A low cost/high performance hydrogen or reformate/air stack technology is being developed based on ultra-low platinum loadings and non-machined, inexpensive elements for flow-fields and bipolar plates. On-board methanol reforming is compared to the option of direct methanol fuel cells in light of recent significant power density increases demonstrated in the latter.     

Effect of inorganic constituents on chemical oxygen demand—I. Bromides are unneutralizable by mercuric sulfate complexation

Chemical oxygen demand (COD) assays are widely used for the estimation of the organic carbon content of water and wastewater. The procedure is subject to interference by free halogen ions, the oxidation of which creates artificially high COD values. As part of an investigation of the interferences involved in the COD determination of chemical industries wastewaters, we found that mercuric sulfate complexation, the standard procedure for neutralizing the halogen effects, is suitable for chlorides but is not applicable to bromides. This observation is true both in the presence or absence of chloride or ammonia. Care should therefore be exercised in the interpretation of COD data for bromide-containing samples.     

Effect of inorganic constituents on chemical oxygen demand—II. Organic carbon to halogen ratios determine halogen interference

The dependency of free halogen ion oxidation in chemical oxygen demand (COD) assays on the organic content of the sample was investigated. Halogen interference was reduced at increasing glucose or potassium hydrogen phthalate concentration; in each case, a threshold ratio of organic matter to halogen existed, above which halogen oxidation was masked. This ratio depended upon the presence of mercuric sulfate in the case of chloride but not of bromide. It was also affected by the ease of oxidation of both the organic molecule and the halogen ion, as well as by their actual COD. Thus, bromide oxidation was more difficult to prevent than that of chloride, and phthalate exerted a stronger masking effect than glucose.     

A Combined System for Automated Ellipsometry and for Network Analysis Based on a Microcomputer

ABSTRACT

A Microcomputer has been employed for the automation of two types of measurements: Ellipsometry, and ac impedance in a wide frequency range (“network analysis”). These measurements are combined in the characterization of electrochemical interfaces. An identical simple and fast algorithm has been employed in both cases for the digital analysis of a sinusoidal signal. The rotating analyzer ellipsometer has a time resolution of 0.01 sec and a precision of 0.01 deg, following 1 sec integration time. The network analyzer generates a complex plane plot in the range of 10mHz-1kHz in 5 min. These specification have been achieved by employing only basic electrochemical instrumentation and a manual ellipsometer, in conjunction with a low cost microcomputer.     

Differentiating multiple relationships from multiple dimensions of involvement: Therapeutic space at the interface of client, therapist, and society.

This article focuses on redirecting current thinking from multiple relationships to the multiple dimensions of our involvements with clients. Given that people's readiness for human involvement is both desirable and unavoidable, recognizing and managing these multiple dimensions of involvement is at the heart of professional interactions. A triangular space, formed at the intersection of societal, therapist and client features, forms the framework in which therapeutic work occurs. In practice, a balance should be maintained within and among five principles of clinical and ethical practice. These are beneficence, respect for client autonomy, self-awareness, self-interest, and openness to objective input. An applied section considers the sources of imbalance in the proper management of the multiple dimensions of therapists' involvements in the psychotherapeutic relationship via a brief consideration of two case situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A printed circuit board approach to measuring current distribution in a fuel cell

A new method of measuring current distribution in a polymer electrolyte fuel cell of active area 100cm2 has been demonstrated, using a printed circuit board (PCB) technology to segment the current collector and flow field. The PCB technique was demonstrated to be an effective approach to fabricating a segmented electrode and provide a useful tool for analysing cell performance at different reactant gas flow rates and humidification strategies. In this initial chapter of work with the segmented cell, we describe measured effects on current distribution of cathode and anode gas stream humidification levels in a hydrogen/air cell, utilizing a NafionTM 117 membrane and single serpentine channel flow fields, and operating at relatively high gas flow rates. Effects of the stoichiometric flow of air are also shown. A clear trend is seen, apparently typical for a thick ionomeric membrane, of lowering in membrane resistance down the flow channel, bringing about the highest local current density near the air outlet. This trend is reversed at low stoichiometric flows of air. At an air flow rate less than three times stoichiometry, the local performance starts to drop significantly from inlet to outlet, as local oxygen concentration drop overshadows the lowering in resistance along the direction of flow.