CETO

Abstract: The latest full-scale version of the CETO wave energy converter (WEC) is described, along with its principle of operation, key features and site selection. At the time of writing, a full-scale prototype test site was under development at a coastal site approximately 37 km to the south west. Some pragmatic issues pertaining to the use of global wave model data and in-situ observations are discussed in the context of this commercial venture.

Abstract: Publisher Summary This chapter discusses a general, simple and pedagogical framework based on Cartesian exponential type orbitals (CETO's) functions, to obtain atomic and molecular integrals, which can be potentially used within a LCAO computational system. One and two electron integrals over various operator kinds have been solved and analytical forms found as well, proving in this manner the flexibility and complete possibilities of the proposed methodology. Two center density expansions into separate centers have been employed successfully to overcome the many center integral problem. CETO functions appear in this manner as a plausible alternative to the present Gaussian Type Orbitals (GTO) quantum chemical computational flood, constituting the foundation of another step signaling the path toward Slater type orbital (STO) integral calculation. Many interesting methodological ideas, along the description of CETO's and their alternative forms: spherical exponential type orbitals (SETO's), laplace exponential type orbitals (LETO's), well-oriented CETO's (WO-CETO's), and elementary CETO (E-CETO's), have been also defined: Logical Kronecker delta and nested summation symbols among others. Both concepts permit easily written integrals and related formulae within a compact mathematical formalism, which possess an immediate and intuitive translation to high level programming languages.

Abstract: We have studied the structural and electronic properties of Ce2Ti2O7 (CeTO) and Pr2Ti2O7 (PrTO) by first-principles density functional theory calculations. The computed structural parameters are in fairly good agreement with the available experimental findings. Band structure calculations using the GGA+U approach predict an insulating ground state for the herein studied compounds. The insulating band gaps of 2.00 eV and 2.83 eV are found for CeTO and PrTO, respectively. The analysis of the density of states reveals that the strongly localized RE 4f levels act as charge-trapping sites, predicting a lower photocatalytic activity for CeTO. We have also calculated the optical properties for both CeTO and PrTO. Based on these properties, it is predicted that these titanates are insensitive to ultra-violet radiation, while they are more sensitive to frequencies of the radiation in visible and early UV regions.

Abstract: CETO functions and their properties are defined and described, to provide a means of obtaining general expressions for many-center many-electron integral formulae. Compact integral expressions are written by means of nested summation symbols, a new concept developed in this paper. Integrals over CETO functions are computed by means of a set of several auxiliary integral forms. No transformations other than frame rotations are needed to compute the usual integral terms. The formulae obtained are immediately programmable in any high level language and the parallelizable terms are obtained with a simple rule. Results can be considered an encouraging alternative way to solve the STO integral problem. Keywords: many-center AO integrals, molecular basis sets, ETO, STO, CETO.