Zwischen Scharia und der Suche nach frischem Kapital: Über die Einführung des islamischen Bankwesens in Kasachstan und Kirgistan

Das islamische Bankwesen hat in den Republiken Kasachstan und Kirgistan in den Jahren seit der Finanzkrise von 2007 Fuß gefasst. Mit der Bank Al-Hilal in Kasachstan und der EkoIslamikBank in Kirgistan sind heute zwei kommerzielle Institute aktiv, die in ihren jeweiligen Nischen mit Wachstum rechnen können. Eine flächendeckende Einführung islamischer Finanzpraktiken in beiden Ländern und in der gesamten Region steht allerdings noch vor bedeutenden Herausforderungen. In Kasachstan ist die Abhängigkeit von staatlichen Impulsen zu nennen, während in Kirgistan das anhaltende Regulierungsversagen die Erwartungen dämpft. Schließlich blockiert länderübergreifend eine staatlich organisierte Skepsis gegenüber islamischen Organisationen die weitere Entwicklung des islamischen Bankwesens in Zentralasien

Grinding of transformation-toughened mixed oxide ceramic

During the manufacturing of ceramic components, grinding is an important manufacturing step. It influences the workpiece quality and the operational reliability. Thermomechanical loads during grinding can influence the lifetime and operational reliability of ceramics by modifying their bending strength and subsurface properties. Therefore, it is necessary to consider the influence of the grinding forces and mechanical loads on the strength of the ceramics in order to design a suitable grinding process. In this investigation, a quick-stop device is used to interrupt the grinding process of the newly developed mixed oxide ceramic SHYTZ (strontium hexaaluminate/yttria-toughened zirconia) and the market-established ceramic ATZ (alumina-toughened zirconia). Subsequently, an analysis of the occurring material removal phenomena, the number of active abrasive grains, and the real thermomechanical loads is carried out. It was found that the number of active grains and the material removal phenomena are influenced by the tool specifications. Besides that, the experimentally determined number of active grains was found to be up to 14 times higher than predicted by an analytical model given in literature. Consequently, the calculated single grain chip thickness was found to be up to 12.1% lower than analytically predicted. The investigation of the process forces and thermal loads showed up to 52% higher loads for ATZ than for SHYTZ. The subsequent analysis of the resulting bending strength of the ceramics revealed a lower influence of the grinding process on the strength of SHYTZ than for ATZ. Furthermore, a correlation between the used tool bonding and the resulting thermomechanical loads, bending strength, and residual stresses could be observed. © 2020, The Author(s)

Central Asia Forecasting 2021: Results from an Expert Survey

The 'Central Asia Forecasting' study, jointly implemented by the Friedrich Ebert Foundation (FES), the OSCE Academy in Bishkek, and the SPCE Hub, aims to help strengthen EU-Central Asia relations. The study results are intended to stimulate the debate on the region, foster understanding of the common challenges and opportunities, and encourage data-driven policymaking. It is a pilot project that will be followed by an annual or biennial study to analyse regional trends over time. The audience that we aim to address with this report comprises the broader public in Europe and Central Asia, civil society representatives, regional experts, researchers and especially EU foreign-policy makers. For this study, a human-judgement forecasting method was employed in the form of an opinion survey among experts and the informed public on developments in the region in the next three years. In total, 144 respondents took our 20-minute survey. About half of the respondents are Central Asian citizens and half are from outside the region. The majority are affiliated with academic institutions and think tanks. This report launch will present the analysis of the survey responses regarding domestic politics and regional affairs, global challenges affecting the region, and EU-Central Asian relations

Influence of dressing strategy on tool wear and performance behavior in grinding of forming tools with toric grinding pins

The performance of grinding tools in grinding processes and the resulting surface and subsurface properties depend on various factors. The condition of the grinding tool after dressing is one of these factors. However, the influence of the dressing process on the condition of the grinding tool depends on the selected process parameters and is difficult to predict. Therefore, this paper presents an approach to describe the influence of the dressing process on tool wear of toric grinding pins and the resulting subsurface modification. For this purpose, toric grinding pins with a vitrified bond were dressed with two different strategies and the wear and operational behavior were investigated when grinding AISI M3:2 tool steel with two different grinding strategies. In general, the investigations have shown that the dressing process influences the performance and wear behavior differently depending on the grinding strategy used. The degree of clogging is influenced by the geometric contact sizes. In the case of small engagement cross sections with simultaneously large contact lengths the thermal tool load is distributed over a small annular area of the tool and favors clogging. Crushing and additional transverse loading of the grains result in an almost clog-free tool surface. This also leads to a lower G-ratio. Crushing leads to an intensified decrease of the torus radii. The influence of the dressing strategy can also be observed in the induced residual stresses. Toric grinding pins dressed by crushing induce lower compressive residual stresses into the workpiece, which can be attributed to the self-sharpening effect. This effect reduces the mechanical and thermomechanical load of the workpiece during machining

Politischer Protest in Zentralasien: Potentiale und Dynamiken

Die Studie befasst sich mit der Frage, ob es auf absehbare Zeit in Zentralasien zu gesellschaftlichen Umbrüchen ähnlich denen im arabischen Raum kommen könnte. Auch in Kasachstan, Usbekistan, Turkmenistan, Kirgistan und Tadschikistan sorgen autoritäre Herrschaftsverhältnisse, soziale Missstände, Korruption und Selbstbereicherung der Eliten für große Frustration. Gleichzeitig verbreiten sich elektronische Kommunikationsmedien rasant und Online-Netzwerke werden immer populärer. Mit den wachsenden Möglichkeiten individueller Artikulation wird Protest zusehends unvorhersehbar, die Akteurslandschaft unübersichtlicher und das Verhältnis von Politik und Gesellschaft insgesamt kontingenter. In fünf Fallstudien identifizieren die Autoren diejenigen Faktoren, die das Potential haben, zu politischen Protesten zu führen, in Revolten umzuschlagen oder gar in eine Revolution zu münden. Ausmaß und Dynamik etwaiger Proteste werden auch in Zentralasien künftig verstärkt von der Nutzung der neuen Medien abhängen. Deren dynamisierendes Potential wird zwar durch staatliche Zensurmaßnahmen eingehegt, doch wird dies auf Dauer nicht verhindern, dass sich in den zentralasiatischen Staaten eine neue Öffentlichkeit ausbildet, die ihre Aufmerksamkeit flexibler einsetzt und Lösungen für Probleme zeitnah einfordert. Die deutsche und europäische Politik, die auf Stabilitätserwartungen beruht, ist auf den sich abzeichnenden Wandel in Zentralasien nur unzureichend eingestellt. Sie wird jedoch auf Dauer nicht umhinkönnen, ihre Politik gegenüber den autoritären Regimen in der Region zu überdenken, die Prioritäten neu zu gewichten und sich für eine Politik einzusetzen, die die Inklusion der Zivilgesellschaften in den globalen Erfahrungshorizont ermöglicht. (Autorenreferat

Suitability of natural rocks as materials for cutting tools

This study presents an investigation of the usability and suitability of natural rocks as cutting tool materials. Therefore, indexable inserts are manufactured from eight different rocks and two mono minerals in this study and are used for turning of an aluminium alloy. Besides that, a characterization of the rock properties is performed. The wear of the rock tools and the surface roughness of the workpiece generated by the tools are used to evaluate their operational behaviour. Subsequently, the rock properties and the corresponding operational behaviour are used to assess the suitability of the rocks as cutting tool material. The results show that rock inserts can be used as cutting material for the turning of an aluminium alloy showing a width of wear marks between 83 and 1665 µm at the flank face after a cutting length of 500 m depending on the rock used. Furthermore, it is shown that rock tools are able to achieve surface roughness values which are comparable to those obtainable by using a conventional cemented carbide insert. The study shows that natural rocks can generally be used as alternative cutting material for the turning of aluminium. In addition a possible way for a systematic investigation and assessment of the suitability of natural rocks as cutting tool materials is presented, the relevance of the rock properties for the operational behaviour of the rock inserts is described and relevant future research topics concerning the use of rocks as cutting tool material are identified

Slow and fast single photons from a quantum dot interacting with the excited state hyperfine structure of the Cesium D1-line

Hybrid interfaces between distinct quantum systems play a major role in the implementation of quantum networks. Quantum states have to be stored in memories to synchronize the photon arrival times for entanglement swapping by projective measurements in quantum repeaters or for entanglement purification. Here, we analyze the distortion of a single-photon wave packet propagating through a dispersive and absorptive medium with high spectral resolution. Single photons are generated from a single In(Ga)As quantum dot with its excitonic transition precisely set relative to the Cesium D1 transition. The delay of spectral components of the single-photon wave packet with almost Fourier-limited width is investigated in detail with a 200 MHz narrow-band monolithic Fabry-Pérot resonator. Reflecting the excited state hyperfine structure of Cesium, “slow light” and “fast light” behavior is observed. As a step towards room-temperature alkali vapor memories, quantum dot photons are delayed for 5 ns by strong dispersion between the two 1.17 GHz hyperfine-split excited state transitions. Based on optical pumping on the hyperfine-split ground states, we propose a simple, all-optically controllable delay for synchronization of heralded narrow-band photons in a quantum network.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeEC/H2020/679183/EU/Entanglement distribution via Semiconductor-Piezoelectric Quantum-Dot Relays/SPQRe

Digital pulse-shape discrimination of fast neutrons and gamma rays

Discrimination of the detection of fast neutrons and gamma rays in a liquid scintillator detector has been investigated using digital pulse-processing techniques. An experimental setup with a 252Cf source, a BC-501 liquid scintillator detector, and a BaF2 detector was used to collect waveforms with a 100 Ms/s, 14 bit sampling ADC. Three identical ADC's were combined to increase the sampling frequency to 300 Ms/s. Four different digital pulse-shape analysis algorithms were developed and compared to each other and to data obtained with an analogue neutron-gamma discrimination unit. Two of the digital algorithms were based on the charge comparison method, while the analogue unit and the other two digital algorithms were based on the zero-crossover method. Two different figure-of-merit parameters, which quantify the neutron-gamma discrimination properties, were evaluated for all four digital algorithms and for the analogue data set. All of the digital algorithms gave similar or better figure-of-merit values than what was obtained with the analogue setup. A detailed study of the discrimination properties as a function of sampling frequency and bit resolution of the ADC was performed. It was shown that a sampling ADC with a bit resolution of 12 bits and a sampling frequency of 100 Ms/s is adequate for achieving an optimal neutron-gamma discrimination for pulses having a dynamic range for deposited neutron energies of 0.3-12 MeV. An investigation of the influence of the sampling frequency on the time resolution was made. A FWHM of 1.7 ns was obtained at 100 Ms/s.Comment: 26 pages, 14 figures, submitted to Nuclear Instruments and Methods in Physics Research

Pedagogía social : revista interuniversitaria

Monográfico con el título: "Redes territoriales de acción socioeducativa: una apuesta por la innovación social colaborativa"Título, resumen y palabras clave también en portuguésResumen basado en el de la publicaciónEstudio cualitativo, localizado en Estados Unidos, presenta un análisis en profundidad sobre el liderazgo en escuelas y organizaciones comunitarias que ayudan a conectar a los alumnos y a las familias con recursos educativos fundamentales. Los datos han sido recopilados a partir de 132 entrevistas con personas que han experimentado las complejidades sociales de la indigencia. Los resultados sugieren que el liderazgo participativo fomenta el aprendizaje, el simbolismo, el desarrollo de la identidad y la responsabilidad. El tipo de liderazgo promete brindar oportunidades para los desfavorecidos, que no tienen acceso a recursos o relaciones de importancia.ES

Wigner time delay induced by a single quantum dot

The research leading to these results has received funding from the European Research Council (ERC) under the European Union's Seventh Framework ERC Grant Agreement No. 615613 and from the German Research Foundation Project (DFG) No. RE2974/5-1. A.C. and J.S. gratefully acknowledge the support by the DFG through project B1 of the SFB 910. The Wurzburg group is grateful for support by the State of Bavaria.Resonant scattering of weak coherent laser pulses on a single two-level system (TLS) realized in a semiconductor quantum dot is investigated with respect to a time delay between incoming and scattered light. This type of time delay was predicted by Wigner in 1955 for purely coherent scattering and was confirmed for an atomic system in 2013 [R. Bourgain et al., Opt. Lett. 38, 1963 (2013)]. In the presence of electron-phonon interaction we observe deviations from Wigner’s theory related to incoherent and strongly non-Markovian scattering processes which are hard to quantify via a detuning-independent pure dephasing time. We observe detuning-dependent Wigner delays of up to 530 ps in our experiments which are supported quantitatively by microscopic theory allowing for pure dephasing times of up to 950 ps.PostprintPostprintPeer reviewe