Potential energy surfaces for atomic oxygen reactions: Formation of singlet and triplet biradicals as primary reaction products with unsaturated organic molecules

The experimental study of the interaction of atomic oxygen with organic polymer films under LEO conditions has been hampered by the inability to conduct detailed experiments in situ. As a result, studies of the mechanism of oxygen atom reactions have relied on laboratory O-atom sources that do not fully reproduce the orbital environment. For example, it is well established that only ground electronic state O atoms are present at LEO, yet most ground-based sources are known to produce singlet O atoms and molecules and ions in addition to O(3P). Engineers should not rely on such facilities unless it can be demonstrated either that these different O species are inert or that they react in the same fashion as ground state atoms. Ab initio quantum chemical calculations have been aimed at elucidating the biradical intermediates formed during the electrophilic addition of ground and excited-state O atoms to carbon-carbon double bonds in small olefins and aromatic molecules. These biradicals are critical intermediates in any possible insertion, addition and elimination reaction mechanisms. Through these calculations, we will be able to comment on the relative importance of these pathways for O(3P) and O(1D) reactions. The reactions of O atoms with ethylene and benzene are used to illustrate the important features of the mechanisms of atomic oxygen reaction with unsaturated organic compounds and polymeric materials

A Tale of Two Market Failures: Technology and Environmental Policy

Market failures associated with environmental pollution interact with market failures associated with the innovation and diffusion of new technologies. These combined market failures provide a strong rationale for a portfolio of public policies that foster emissions reduction as well as the development and adoption of environmentally beneficial technology. Both theory and empirical evidence suggest that the rate and direction of technological advance is influenced by market and regulatory incentives, and can be cost-effectively harnessed through the use of economicincentive based policy. In the presence of weak or nonexistent environmental policies, investments in the development and diffusion of new environmentally beneficial technologies are very likely to be less than would be socially desirable. Positive knowledge and adoption spillovers and information problems can further weaken innovation incentives. While environmental technology policy is fraught with difficulties, a long-term view suggests a strategy of experimenting with policy approaches and systematically evaluating their success.technology, research and development, environment, externality, policy

Technological Change and the Environment

Environmental policy discussions increasingly focus on issues related to technological change. This is partly because the environmental consequences of social activity are frequently affected by the rate and direction of technological change, and partly because environmental policy interventions can themselves create constraints and incentives that have significant effects on the path of technological progress. This paper, prepared as a chapter draft for the forthcoming Handbook of Environmental Economics (North-Holland/Elsevier Science), summarizes for environmental economists current thinking on technological change in the broader economics literature, surveys the growing economic literature on the interaction between technology and the environment, and explores the normative implications of these analyses. We begin with a brief overview of the economics of technological change, and then examine three important areas where technology and the environment intersect: the theory and empirical evidence of induced innovation and the related literature on the effects of environmental policy on the creation of new, environmentally friendly technology; the theory and empirics of environmental issues related to technology diffusion; and analyses of the comparative technological impacts of alternative environmental policy instruments. We conclude with suggestions for further research on technological change and the environment.technological change, induced innovation, environment, policy

The Induced Innovation Hypothesis and Energy-Saving Technological Change

We develop a methodology for testing Hick’s induced innovation hypothesis by estimating a product-characteristics model of energy-using consumer durables, augmenting the hypothesis to allow for the influence of government regulations. For the products we explored, the evidence suggests: (i) the rate of overall innovation was independent of energy prices and regulations, (ii) the direction of innovation was responsive to energy price changes for some products but not for others, (iii) energy price changes induced changes in the subset of technically feasible models that were offered for sale, (iv) this responsiveness increased substantially during the period after energy-efficiency product labeling was required, and (v) nonetheless, a sizeable portion of efficiency improvements were autonomous.

Light and heavy multiquark spectroscopy

The dynamics of multiquark binding is revisited in the light of the recent experimental results. It is emphasized that some configurations mixing light and heavy flavours are among the most favourable for stable or metastable multiquarks. The nuclear-physics type of approach predicting the so-called hadron-hadron molecules is compared to direct studies in terms of quark interaction.Comment: Invited talk at QCD05, 12th International QCD Conference, July 4-9, 2005 - Montpellier (France), to appear in the proceedings edited by S. Nariso

Controlled levels of protein modification through a chromatography-mediated bioconjugation.

Synthetically modified proteins are increasingly finding applications as well-defined scaffolds for materials. In practice it remains difficult to construct bioconjugates with precise levels of modification because of the limited number of repeated functional groups on proteins. This article describes a method to control the level of protein modification in cases where there exist multiple potential modification sites. A protein is first tagged with a handle using any of a variety of modification chemistries. This handle is used to isolate proteins with a particular number of modifications via affinity chromatography, and then the handle is elaborated with a desired moiety using an oxidative coupling reaction. This method results in a sample of protein with a well-defined number of modifications, and we find it particularly applicable to systems like protein homomultimers in which there is no way to discern between chemically identical subunits. We demonstrate the use of this method in the construction of a protein-templated light-harvesting mimic, a type of system which has historically been difficult to make in a well-defined manner

Technological Change and the Environment

Environmental policy discussions increasingly focus on issues related to technological change. This is partly because the environmental consequences of social activity are frequently affected by the rate and direction of technological change, and partly because environmental policy interventions can themselves create constraints and incentives that have significant effects on the path of technological progress. This paper, prepared as a chapter draft for the forthcoming Handbook of Environmental Economics (North-Holland/Elsevier Science), summarizes for environmental economists current thinking on technological change in the broader economics literature, surveys the growing economic literature on the interaction between technology and the environment, and explores the normative implications of these analyses. We begin with a brief overview of the economics of technological change, and then examine three important areas where technology and the environment intersect: the theory and empirical evidence of induced innovation and the related literature on the effects of environmental policy on the creation of new, environmentally friendly technology; the theory and empirics of environmental issues related to technology diffusion; and analyses of the comparative technological impacts of alternative environmental policy instruments. We conclude with suggestions for further research on technological change and the environment.