Localization for Schrodinger operators with random vector potentials

We prove Anderson localization at the internal band-edges for periodic magnetic Schr{\"o}dinger operators perturbed by random vector potentials of Anderson-type. This is achieved by combining new results on the Lifshitz tails behavior of the integrated density of states for random magnetic Schr{\"o}dinger operators, thereby providing the initial length-scale estimate, and a Wegner estimate, for such models

Influence of boron additions on physical and mechanical properties of arc-melted tungsten and tungsten - 1 percent tantalum alloy

Influence of boron additions on physical and mechanical properties of arc-melted tungsten and of tungsten-tantalum allo

Localization on quantum graphs with random vertex couplings

We consider Schr\"odinger operators on a class of periodic quantum graphs with randomly distributed Kirchhoff coupling constants at all vertices. Using the technique of self-adjoint extensions we obtain conditions for localization on quantum graphs in terms of finite volume criteria for some energy-dependent discrete Hamiltonians. These conditions hold in the strong disorder limit and at the spectral edges

Lower-cost tungsten-rhenium alloys

Tungsten-rhenium alloys with a substantially more dilute rhenium content have ductilities and other mechanical properties which compare favorably with the tungsten-rhenium alloys having much higher concentrations of the costly rhenium

Economics of Hot Water Dipping

Hot water dipping is an appropriate method to protect apples against spoilage caused by gloeosporium rot. Tests on the varieties Topaz and Ingrid Marie at the OVB Jork (Germany) have demonstrated an effective reduction of spoilage from between 80% and 92% in charges by an infection rate of 40%. The result of an intensive R&D process between 2002 and 2003 is the development of a praxis-tested big box (300 kg) dipping station. With the first Bio Dipping systems now on the market it has now been possible to analyse the economics of this process. The costs of the systems per apple farm have been calculated from the fixed capital costs for the system itself (including maintenance costs) and from the variable costs based on an average crop of 250 t gloeosporium-sensitive varieties, which would be treated with this process every season. The Return on Investment depends largely on the effectiveness of the process in reducing spoilage and on the level of infection within the crop, assuming that losses occur in storage. Based on an average effectivity of 85% and an infection rate of 10% it has been possible to calculate an amortisation within eight years. Higher levels of infection and a consistent effectivity of 85% shorten this time span significantly. The attractions of the hot water dipping process are in the opinion of the research team at the OVB Jork not merely economically convincing in terms of ROI. By reducing the levels of spoilage throughout the entire supply chain, it is for the first time possible to make a significant development in the sustainable quality management of organic apples, providing clear benefits for both consumer, trade and the grower

Effects of Grain Size on the Tensile and Creep Properties of Arc-melted and Electron-beam-melted Tungsten at 2250 Deg to 4140 Deg f

Effects of grain size on tensile and creep properties of arc melted and electron beam melted tungste

Understanding the Random Displacement Model: From Ground-State Properties to Localization

We give a detailed survey of results obtained in the most recent half decade which led to a deeper understanding of the random displacement model, a model of a random Schr\"odinger operator which describes the quantum mechanics of an electron in a structurally disordered medium. These results started by identifying configurations which characterize minimal energy, then led to Lifshitz tail bounds on the integrated density of states as well as a Wegner estimate near the spectral minimum, which ultimately resulted in a proof of spectral and dynamical localization at low energy for the multi-dimensional random displacement model.Comment: 31 pages, 7 figures, final version, to appear in Proceedings of "Spectral Days 2010", Santiago, Chile, September 20-24, 201

The weak localization for the alloy-type Anderson model on a cubic lattice

We consider alloy type random Schr\"odinger operators on a cubic lattice whose randomness is generated by the sign-indefinite single-site potential. We derive Anderson localization for this class of models in the Lifshitz tails regime, i.e. when the coupling parameter $\lambda$ is small, for the energies $E \le -C \lambda^2$.Comment: 45 pages, 2 figures. To appear in J. Stat. Phy

High-strength tungsten alloy with improved ductility

Alloy combines superior strength at elevated temperatures with improved ductility at lower temperatures relative to unalloyed tungsten. Composed of tungsten, rhenium, hafnium, and carbon, the alloy is prepared by consumable electrode vacuum arc-melting and can be fabricated into rod, plate, and sheet

Spectral extrema and Lifshitz tails for non monotonous alloy type models

In the present note, we determine the ground state energy and study the existence of Lifshitz tails near this energy for some non monotonous alloy type models. Here, non monotonous means that the single site potential coming into the alloy random potential changes sign. In particular, the random operator is not a monotonous function of the random variables