Safety evaluation of substitutes for phosphates in detergents

The safety of products is of interest and concern to the whole community, but the manufacturer has the primary responsibility. The information given in this paper demonstrates an intent, on the part of a manufacturer, to have safe products. The procedures used to establish product safety have been illustrated, and comments have been made about the time, money, and effort that are entailed. But time and money are not enough; experience, expertise, and interest are also essential. We believe that the need for these elements can best be met by the interchange of knowledge between industrial, governmental, academic, and professional circles.     

The 1955 and 1957 research conferences: The identification of creative scientific talent.

2 conferences, one in August 1955 and the other in August 1957, on "The Identification of Creative Scientific Talent" were supported financially by the National Science Foundation. Titles of research reports and authors are presented. Reports of special committees at each conference are summarized. "A multiplicity of hypotheses and problems needing research… emerged throughout both conferences. It is hoped that concurrent attacks on problems of creativity will be undertaken by researchers in industry, government, universities, and school systems." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of the criterion problem for one group of medical specialists.

The sample consisted of 190 Utah physicians fully certified as specialists by an American Board. 80 scores relevant to the performance of these physicians were intercorrelated and factor analyzed using the principal components solution based on eigenvalues and eigenvectors. The 29 factors which had an eigenvalue greater than 1.00 were rotated by the varimax procedure and interpreted. The most important finding was the great criterion complexity for this group of medical specialists. This complexity suggests that one cannot adequately measure physician performance on the basis of a single score or a few scores. Instead, one must obtain a relatively large number of scores. Performance in poth premedical and medical education was independent of performance as a physician. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Energy and technology lessons since Rio

The 1992 Framework Convention on Climate Change created the basic international architecture for addressing climate change. That treaty was negotiated at a time when the research literature examining emissions mitigation and the role of energy technology was relatively limited. In the two subsequent decades a great deal has been learned. The problem of stabilizing the concentration of greenhouse gases in the atmosphere has proved far more difficult than envisioned in 1992 and the role of technology appears even more important when emissions mitigation strategies are co-developed in the context of multiple competing ends.     

The effect of resin finish on the dimensional stability of cotton knitted fabric

In this article, the effect of resin finish on the degree of set is discussed. Furthermore, the relationship of the degree of set and dimensional stability is analyzed. After relaxation treatments, the yarns in a fabric would be set at a certain level. As the fabric is subjected to prolonged relaxation treatments, the yarn will become more set until the shape of the unraveled yarn is similar to the shape of the loop in the fabric. The yarn that is removed from a knitted fabric has a curvature value close to zero, and the curvature is exactly as the corresponding position at the knitted loop. From previous research, it is known that the degree of set affects the dimensional properties in a plain knitted fabric. In this article, the degree of set increases with resin level. It explains why the resin finish can stabilize the dimensional properties indirectly.     

Sample overloading effects in polymer characterization by field-flow fractionation

There are two subtechniques of field-flow fractionation (FFF), thermal FFF and flow FFF, that have been successfully employed for polymer fractionation and characterization. These techniques are primarily analytical in nature, yielding accurate polymer characteristics from small sample loads (～ 10 μg or less, depending on detection sensitivity). In this study the effects of increasing sample size are examined. Modest increases in load are found to result in shifts toward higher retention volumes. These modest loads also result in some broadening of the sample peaks without a major loss of peak symmetry. Excessive loading, by contrast, appears to give rise both to skewed peaks and to new artifact peaks at higher levels of retention. These observations are discussed in terms of the concentration dependence of various properties (viscosity, diffusivity, thermal diffusivity) which influence polymer transport through the FFF channel. The results are used to indicate upper limits to suitable sample concentrations.     

Feedforward-feedback control of a solid oxide fuel cell power system

One of the main challenges for wide-spread utilization of the solid oxide fuel cell (SOFC) power systems is how to achieve high electrical efficiency without increasing the degradation rate of the fuel cells. To run the SOFC power system at high efficiency over a long period of time, properly designed controllers are indispensable.Although a number of various approaches to control SOFC have been proposed so far, it seems that the design of control system, along with simple tuning procedure, has not been treated in a consistent manner. This issue is addressed in the present paper resulting in a feedforward-feedback control structure. The feedforward part is based on the stoichiometry of electro-oxidation, reforming and combustion reactions, which allow immediate response to variable current demand. The feedback part performs additional fine adjustment of fuel and air supply in order to minimize the undesired system temperatures variations. The selection of pairings of manipulated and controlled variables for control is based on physical knowledge of the system. Input/output pairing for single-loop feedback control is assessed by the relative gain analysis. An efficient procedure for tuning the parameters of the feedback controllers is suggested, relying on simple open-loop step responses of the system.The proposed low-level control is assessed on a detailed physical model of a 2.5 kW SOFC power system by simulating two nonstationary load regimes. Simulations show that the control provides a robust operation under large load variations while meeting the operating constraints. Due to its simplicity, the control is feasible for implementation on a real SOFC system.     

Thermal characteristics of an air-cooled open-cathode proton exchange membrane fuel cell stack via numerical investigation

In light of stricter emissions regulations and depleting fossil fuel reserves, fuel cell vehicles (FCVs) are one of the leading alternatives for powering future vehicles. An open-cathode, air-cooled proton exchange membrane fuel cell (PEMFC) stack provides a relatively simple electric generation system for a vehicle in terms of system complexity and number of components. The temperature within a PEMFC stack is critical to its level of performance and the electrochemical efficiency. Previously created computational models to study and predict the stack temperature have been limited in their scale and the inaccurate assumption that temperature is uniform throughout. The present work details the creation of a numerical model to study the temperature distribution of an 80-cell Ballard 1020ACS stack by simulating the cooling airflow across the stack. Using computational fluid dynamics, a steady-state airflow simulation was performed using experimental data to form boundary conditions where possible. Additionally, a parametric study was performed to investigate the effect of the distance between the stack and cooling fan on stack performance. Model validation was performed against published results. The temperature distribution across the stack was identical for the central 70% of the cells, with eccentric temperatures observed at the stack extremities, while the difference between coolant and bipolar plate temperatures was approximately 10°C at the cooling channel outlets. The results of the parametric study showed that the fan-stack distance has a negligible effect on stack performance. The assumptions regarding stack temperature uniformity and measurement were challenged. Lastly, the hypothesis regarding the negligible effect of fan-stack distance on stack performance was confirmed.