2,018 research outputs found

    Environmentally Friendly Machining

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    Environment-Friendly Machining provides an in-depth overview of environmentally-friendly machining processes, covering numerous different types of machining in order to identify which practice is the most environmentally sustainable. The book discusses three systems at length: machining with minimal cutting fluid, air-cooled machining and dry machining. Also covered is a way to conserve energy during machining processes, along with useful data and detailed descriptions for developing and utilizing the most efficient modern machining tools. Researchers and engineers looking for sustainable machining solutions will find Environment-Friendly Machining to be a useful volume

    Electronic autoionization and vibrational-state distributions in resonant multiphoton ionization of H2

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    We investigate the effects of electronic autoionization on the vibrational branching ratios in resonant multiphoton ionization of H2. Ab initio calculations are performed to obtain the vibrational branching ratios for (3+1) resonant-enhanced multiphoton ionization (REMPI) of H2 via the C 1Πu state. Our calculations include the effects of the dissociative 1Πg(1σu1πu) autoionizing state and properly account for the interference between the direct and the indirect (autoionization) channels. We find that the direct and indirect amplitudes are comparable for excitation via the higher (vi≥2) vibrational levels of the C state. Autoionization greatly enhances the branching ratios for Δv≠0 transitions. These calculations underscore the necessity for a proper treatment of both the direct and indirect contributions in understanding the REMPI of molecules via autoionizing states

    Gas-liquid transition in the model of particles interacting at high energy

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    An application of the ideas of the inertial confinement fusion process in the case of particles interacting at high energy is investigated. A possibility of the gas-liquid transition in the gas is considered using different approaches. In particular, a shock wave description of interactions between particles is studied and a self-similar solution of Euler's equation is discussed. Additionally, Boltzmann equation is solved for self-consistent field (Vlasov's equation) in linear approximation for the case of a gas under external pressure and the corresponding change of Knudsen number of the system is calculated.Comment: 24 pages, 2 figur

    Structure of the mirror nuclei 9^9Be and 9^9B in a microscopic cluster model

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    The structure of the mirror nuclei 9^9Be and 9^9B is studied in a microscopic α+α+n\alpha+ \alpha+ n and α+α+p\alpha+ \alpha+ p three-cluster model using a fully antisymmetrized 9-nucleon wave function. The two-nucleon interaction includes central and spin-orbit components and the Coulomb potential. The ground state of 9^9Be is obtained accurately with the stochastic variational method, while several particle-unbound states of both 9^9Be and 9^9B are investigated with the complex scaling method.The calculation for 9^9Be supports the recent identification for the existence of two broad states around 6.5 MeV, and predicts the 322\frac{3}{2}^{-}_2 and 522\frac{5}{2}^{-}_2 states at about 4.5 MeV and 8 MeV, respectively. The similarity of the calculated spectra of 9^9Be and 9^9B enables one to identify unknown spins and parities of the 9^9B states. Available data on electromagnetic moments and elastic electron scatterings are reproduced very well. The enhancement of the EE1 transition of the first excited state in 9^9Be is well accounted for. The calculated density of 9^9Be is found to reproduce the reaction cross section on a Carbon target. The analysis of the beta decay of 9^9Li to 9^9Be clearly shows that the wave function of 9^9Be must contain a small component that cannot be described by the simple α+α+n\alpha+ \alpha+ n model. This small component can be well accounted for by extending a configuration space to include the distortion of the α\alpha-particle to t+pt+p and h+nh+n partitions.Comment: 24 page

    Theory of excited state absorptions in phenylene-based π\pi-conjugated polymers

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    Within a rigid-band correlated electron model for oligomers of poly-(paraphenylene) (PPP) and poly-(paraphenylenevinylene) (PPV), we show that there exist two fundamentally different classes of two-photon Ag_g states in these systems to which photoinduced absorption (PA) can occur. At relatively lower energies there occur Ag_g states which are superpositions of one electron - one hole (1e--1h) and two electron -- two hole (2e--2h) excitations, that are both comprised of the highest delocalized valence band and the lowest delocalized conduction band states only. The dominant PA is to one specific member of this class of states (the mAg_g). In addition to the above class of Ag_g states, PA can also occur to a higher energy kAg_g state whose 2e--2h component is {\em different} and has significant contributions from excitations involving both delocalized and localized bands. Our calculated scaled energies of the mAg_g and the kAg_g agree reasonably well to the experimentally observed low and high energy PAs in PPV. The calculated relative intensities of the two PAs are also in qualitative agreement with experiment. In the case of ladder-type PPP and its oligomers, we predict from our theoretical work a new intense PA at an energy considerably lower than the region where PA have been observed currently. Based on earlier work that showed that efficient charge--carrier generation occurs upon excitation to odd--parity states that involve both delocalized and localized bands, we speculate that it is the characteristic electronic nature of the kAg_g that leads to charge generation subsequent to excitation to this state, as found experimentally.Comment: Revtex4 style, 2 figures inserted in the text, three tables, 10 page

    Increasing Dominance - the Role of Advertising, Pricing and Product Design

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    Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods, we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal. We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via the effect on advertising

    A case study on risk and return implications of emissions trading in power generation investments

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    This paper explores quantitative implications of the European Union Emissions Trading Scheme (EU ETS) on power capacity investment appraisal in a deregulated market. Risk and return of three different types of power plants, a gas-fired condensing power plant; a hydro power plant with a reservoir; and an off-shore wind power farm, are studied and compared in the regulatory environment of Finland. A single-firm exogenous and stochastic price model is used to simulate possible market outcomes. The model runs suggest that emissions trading increases the expected return of all three power plant technologies. The increase in risk is significant only in the case of the gas-fired power plant. Keywords

    Characterization of thrombospondin synthesis, secretion and cell surface expression by human tumor cells

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    Previous studies have shown that thrombospondin (TSP) is an adhesion factor for some human tumor cells. The previous studies have shown further that tumor cells which utilize TSP as an adhesion factor also synthesize it. This study continues the effort to understand how TSP production and expression are regulated in human tumor cells and the consequences of this for the cells. It is shown that differences among cell lines in their capacity to biosynthesize TSP are associated with differences in TSP specific mRNA levels. This indicates that biosynthesis is regulated at the transcriptional level. There is also a direct relationship between TSP biosynthesis and secretion into the culture medium and expression at the cell surface. The cells which are the most biosynthetically active secrete amounts of TSP into the culture medium that are sufficient to elicit a detectable response in the cell-substrate adhesion assay. The kinetics of TSP secretion by these cells are in accord with the kinetics of attachment and spreading of the same cells in the absence of exogenous adhesion factors. These data are consistent with the idea that endogenously produced TSP promotes the adhesion of the cells which synthesize it in an autocrine manner.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42595/1/10585_2005_Article_BF01753679.pd
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