Ab-initio electron transport calculations of carbon based string structures

First-principles calculations show that monatomic strings of carbon have high cohesive energy and axial strength, and exhibit stability even at high temperatures. Because of their flexibility and reactivity, carbon chains are suitable for structural and chemical functionalizations; they also form stable ring, helix, grid, and network structures. Analysis of electronic conductance of various infinite, finite, and doped string structures reveal fundamental and technologically interesting features. Changes in doping and geometry give rise to dramatic variations in conductance. In even-numbered linear chains, strain induces a substantial decrease of conductance. The double covalent bonding of carbon atoms underlies their unusual chemical, mechanical, and transport properties.     

A Structured Approach to the Derivation of Effective Properties for Combined Water and Gas Flow in the EDZ

The generation, accumulation, and release of corrosion gases is an important issue in the assessment of long-term repository performance. For repository concepts in clay-rich rock formations such as the Opalinus Clay of Northern Switzerland the transport path through the Excavation Damage Zone (EDZ) around the emplacement tunnels is of particular interest because the gas transport capacity of the host rock is limited and therefore a significant fraction of the produced gas could be released along the EDZ. This article describes the development of a structured approach to abstract complex geoscientific models of two-phase flow through the EDZ to simplified models suitable for use within a Probabilistic Safety Assessment (PSA). The approach utilizes three different models: a discrete fracture network (DFN) model of the EDZ, an equivalent heterogeneous continuum porous medium (CPM) model and a simplified CPM model suitable for use within PSA. Equivalent properties of the elements of the heterogeneous CPM models are upscaled from DFN realizations. Results from gas injection simulations with the heterogeneous CPM models are then used to derive appropriate parameters for the simplified CPM model. The modeling presented in this article represents the first step in the development of a structured methodology for treatment of gas, solute, and water flow through the EDZ. The emphasis is on methodology development, and both input data and structural models used in this study are of a generic nature and would have to be adapted to the actual conditions at a real repository site.     

On the Number of Distinct Values of a Class of Functions with Finite Domain

By relating the number of images of a function with finite domain to a certain parameter, we obtain both an upper and lower bound for the image set. Even though the arguments are elementary, the bounds are, in some sense, best possible. These bounds are then applied in several contexts. In particular, we obtain the first non-trivial upper bound for the image set of a planar function over a finite field.     

KINETICS OF PHOTOSYNTHETIC APPARATUS ADAPTATION IN Scenedesmus obliquus TO CHANGE IN IRRADIANCE AND LIGHT QUALITY

Abstract— Cells of the unicellular green alga Scenedesmus obliquus grown under high (20 W m^-2) or low (5 W m^-2) irradiancies of white light show all characteristics of sun or shade plants, respectively. When transferred to alternate light conditions, the cells adapt within 6 h. When cells grown under high irradiance of white light are transferred to red (683 nm) or blue (424 nm) light, they show characteristics similar to cells adapted to low or high irradiancies of white light, respectively. This adaptation to different wavelengths takes about 12 h. The underlying changes in the photosynthetic apparatus are discussed.