Different Behavior of Magnetic Impurities in Crystalline and Ammorphous States of Superconductors

It has been observed that the effect of magnetic impurities in a superconductor is drastically different depending on whether the host superconductor is in a crystalline or an amorphous state. Based on the recent theory of Kim and Overhauser (KO), it is shown that as the system is getting disordered, the initial slope of the $T_{c}$ depression is decreasing by a factor $\sqrt{\ell/\xi_{0}}$, when the mean free path $\ell$ becomes smaller than the BCS coherence length $\xi_{0}$, which is in agreement with experimental findings. In addition, for a superconductor in a crystalline state in the presence of magnetic impurities the superconducting transition temperature $T_{c}$ drops sharply from about 50% of $T_{c0}$ (for a pure system) to zero near the critical impurity concentration. This {\sl pure limit behavior} was indeed found by Roden and Zimmermeyer in crystalline Cd. Recently, Porto and Parpia have also found the same {\sl pure limit behavior} in superfluid He-3 in aerogel, which may be understood within the framework of the KO theory.Comment: 7 figures, 20 pages, latex, to appear in Superconductor Science and Technolog

CO2 Based Taxation on Cars Is Rising in Europe

In recent years, CO2 emissions have become the leading basis of assessment for car taxes in most European countries. In July 2009, with a view to pursuing climate policy goals, also Germany began using this factor to assess taxation on cars. The DIW Berlin has carried out a systematic and quantitative comparison of car taxation in Europe.1 The results reveal high tax rates in over ten countries that levy CO2 based tax components and significant differences across vehicle segments. Other observations are periodic adjustments of the assessment basis with regard to fuel-consumption benchmarks. The German reform of the annual vehicle tax (Kraftfahrzeugsteuer) in favour of assessment based on CO2 emissions is weak compared to other countries-too weak to create incentives to buy more fuel efficient vehicles. Moreover, the revision in July 2009 was introduced too late, given that the CO2 emissions of newly registered vehicles have been significantly decreasing since 2006 and given that the new EU directive on reducing the CO2 emissions of cars will directly impact car manufacturers effective 2012.Environmental taxes, Technological change: Government policy, transportation: regulatory policies

Comparison of gurson and lemaitre model in the context of blanking simulation of a high strength steel

The process of blanking takes place in a short band with high accumulated strain undergoing various stress triaxialities. Enhanced implementations for shear and compressive loads of Gurson’s and Lemaitre’s model are directly compared for the same blanking setup. For a dual phase steel DP600 the Lemaitre parameters are identified completely by an inverse strategy, while the parameters of the Gurson’s porous plasticity model are predominantly gained from analysis with a scanning electron microscopy (SEM). The models are validated by comparison of force-displacement curves, time point and location of crack initiation. Advantages and disadvantages of both approaches are discussed with respect to prediction accuracy and costs of parameter identification. Both of the models deliver an exact prediction for the location of the crack and a good prediction of the punch displacement at the onset of cracking

Roman:Kemal Tahir demek istiyor ki...

Taha Toros Arşivi, Dosya No: 133-Kemal Tahir ve Yorgun Savaşçı. Not: Derginin "Kitaplar ve Sanatlar" köşesinde yayımlanmıştır.Unutma İstanbul projesi İstanbul Kalkınma Ajansı'nın 2016 yılı "Yenilikçi ve Yaratıcı İstanbul Mali Destek Programı" kapsamında desteklenmiştir. Proje No: TR10/16/YNY/010

First price auctions under prospect theory with linear probability weighting

Ankara : The Department of Economics, İhsan Doğramacı Bilkent University, 2011.Thesis (Master's) -- Bilkent University, 2011.Includes bibliographical references leaves 23-24.Overbidding in first-price sealed-bid auctions is a well-known result in the auction theory literature. For the possible reasons behind this phenomenon, economists provided many explanations; such as risk aversion, regret theory, and subjective probability weighting. However, for subjective probability weighting to explain overbidding, the probability weighting function (PWF) is needed to be underweighting all probabilities. Such a function is not in accord with PWFs in the prospect theory literature as it suggests a specific function which satisfies certain properties. In this paper we investigate, to what extent prospect theory is able to explain overbidding by using a linear PWF satisfying all of the axiomatic properties (Currim and Sarin, 1989). Moreover, we introduce a non-zero reference point, fully utilizing prospect theory. Our results show that, subjective probability weighting alone is unable to explain overbidding. However, with the non-zero reference point assumption, we obtain partial overbidding.Keskin, KerimM.S

İstanbul Avrupa şehri

Taha Toros Arşivi, Dosya Adı: İstanbul Genel Dokümanlarıİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Soft SUSY Breaking Terms for Chiral Matter in IIB String Compactifications

This paper develops the computation of soft supersymmetry breaking terms for chiral D7 matter fields in IIB Calabi-Yau flux compactifications with stabilised moduli. We determine explicit expressions for soft terms for the single-modulus KKLT scenario and the multiple-moduli large volume scenario. In particular we use the chiral matter metrics for Calabi-Yau backgrounds recently computed in hep-th/0609180. These differ from the better understood metrics for non-chiral matter and therefore give a different structure of soft terms. The soft terms take a simple form depending explicitly on the modular weights of the corresponding matter fields. For the large-volume case we find that in the simplest D7 brane configuration, scalar masses, gaugino masses and A-terms are very similar to the dilaton-dominated scenario. Although all soft masses are suppressed by ln(M_P/m_{3/2}) compared to the gravitino mass, the anomaly-mediated contributions do not compete, being doubly suppressed and thus subdominant to the gravity-mediated tree-level terms. Soft terms are flavour-universal to leading order in an expansion in inverse Kahler moduli. They also do not introduce extra CP violating phases to the effective action. We argue that soft term flavour universality should be a property of the large-volume compactifications, and more generally IIB flux models, in which flavour is determined by the complex structure moduli while supersymmetry is broken by the Kahler moduli. For the simplest large-volume case we run the soft terms to low energies and present some sample spectra and a basic phenomenological analysis.Comment: 40 pages, 9 figures, JHEP style; v2. sentence rephrase