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Conversion of coal to carbon-free energy carriers, [H.sub.2] and electricity, with C[O.sub.2] capture and storage may have the potential to satisfy at a comparatively low cost much of the energy requirements in a carbon-constrained world. In a set of recent studies, we have assessed the thermodynamic and economic performance of numerous coal-to-[H.sub.2] plants that employ [O.sub.2]-blown, entrained-flow gasification and sour water-gas shift (WGS) reactors, examining the effects of system pressure, syngas cooling via quench versus heat exchangers, 'conventional' [H.sub.2] separation via pressure swing adsorption versus novel membrane-based approaches, and various gas turbine technologies for generating co-product electricity. This study focuses on the synergy between [H.sub.2] separation membrane reactors (HSMRs) and syngas cooling with radiant and convective heat exchangers; such 'syngas coolers' invariably boost system efficiency over that obtained with quench-cooled gasification. Conventional [H.sub.2] separation requires a relatively high steam-to-carbon ratio (S/C) to achieve a high level of [H.sub.2] production, and thus is well matched to relatively inefficient quench cooling. In contrast, HSMRs shift the WGS equilibrium by continuously extracting reaction product [H.sub.2], thereby allowing a much lower S/C ratio and consequently a higher degree of heat recovery and (potentially) system efficiency. We first present a parametric analysis illuminating the interaction between the syngas coolers, high temperature WGS reactor, and HSMR. We then compare the performance and cost of six different plant configurations, highlighting (I) the relative merits of the two syngas cooling methods in membrane-based systems, and (2) the comparative performance of conventional versus HSMR-based [H.sub.2] separation in plants with syngas coolers.

The process of low cost ammonia extraction from coal for carbon dioxide storage projects in China is discussed.

The production of wind energy via natural gas turbines and compressed air energy storage to reduce greenhouse gas emissions is analyzed.

Concerns about air pollution, climate change, and oil supply insecurity, requires changes in automotive engine/fuel technologies in directions, that offer both the potential for achieving near-zero emission of air pollutants, and a substitute of petroleum. Alternative automotive engine/fuel options, which are evolving towards these goals, are compared and discussed.

As the number of cars and the amount of driving increase, it becomes necessary to reduce air pollutant emissions per car in order to meet air quality goals. Yet it [...]

Several factors must first be considered before purchasing a charge-coupled device (CCD) camera. Buyers must first examine the camera's quantum efficiency (QE) versus wavelength plot. QE measurements are often made by the CCD manufacturer and simply passed along to the camera maker. In choosing the right camera, the performance of the CCD must first be assessed against the user's requirements. Deciding how much read and dark noise can be tolerated for a specific use can pose a lot of problems. Low-read noise MPP cameras are used for low light level spectroscopy while TE-cooled cameras are used for high light level spectroscopy.

Severe local air pollution, aggravation of the global warming condition and the inaccessibility of coal reserves in China have fueled interest into alternative sources of electricity, such as wind power. Wind power has been in use in China for over 3,000 years. Studies showed that it can provide the same amount of electricity in distant electricity demand centers by combining oversized wind farms, utilizing long-distance transmission lines and large-scale electrical storage. However, problems in funding and the legal structure of the scheme must be addressed.

Alternative sources of energy that are environment friendly are needed to maintain sustainable progress well into the future. Despite current environmental problems caused by fossil fuels, prospects are high for technologies providing new sources of energy. Sustainable development requires efficiency in energy use as well as sources that are beneficial to theenvironment. In this respect, the US needs to implement a new energy policy that would encourage increased energy output and the creation and marketing of new energy sources friendly to the environment.

Manne and Richels (Manne and Richels, 1990) have developed a useful modelling framework for evaluating the potential economic impacts of alternative strategies or coping with greenhouse warning. Their estimate is [...]

Objective. - To determine the usefulness of zinc protoporphyrin, as measured by the Helena Protofluor-Z hematofluorometer, for detecting elevated lead levels. Design. - Observational, descriptive review of laboratory records from a university toxicology laboratory. Setting. - Inner-city university pediatric clinic and two affiliated community clinics in Chicago, Ill. Patients. - Seven hundred seventy-five children younger than 7 years with paired lead-zinc protoporphyrin results. Measurements/Results. - Fifty-six percent had lead levels of at least 0.48 [mu]mol/L and 8% had lead levels of at least 1.21 [mu]mol/L. The sensitivity, positive predictive value, and negative predictive value of a zinc protoporphyrin level of 70 [mu]mol/mol of hemoglobin for detecting a lead level of 0.48 [mu]mol/L were 42%, 66%, and 50%, respectively, and for a lead level of 1.21 [mu]mol/L were 74%, 18%, and 97%, respectively. Receiver operating characteristic curves demonstrated that for detecting lead levels of 0.48 [mu]mol/L with zinc protoporphyrin, the probability of a true-positive result is close to that of a false-positive one. Conclusion. - Zinc protoporphyrin is not a reliable screening test for detecting low blood lead levels. (AJDC. 1993;147:66-68)

Research describing the economics of photovoltaic technology (PV) is presented. In particular a market analysis of amorphous silicon thin-film PV is examined from both commercial and domestic viewpoints.