Technische Universität Darmstadt

About: Technische Universität Darmstadt is a education organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Neutron & Finite element method. The organization has 17316 authors who have published 40619 publications receiving 937916 citations. The organization is also known as: Darmstadt University of Technology & University of Darmstadt.

Phase diagram of neutral quark matter: Self-consistent treatment of quark masses

Abstract: We study the phase diagram of dense, locally neutral three-flavor quark matter within the framework of the Nambu--Jona-Lasinio model. In the analysis, dynamically generated quark masses are taken into account self-consistently. The phase diagram in the plane of temperature and quark chemical potential is presented. The results for two qualitatively different regimes, intermediate and strong diquark coupling strength, are presented. It is shown that the role of gapless phases diminishes with increasing diquark coupling strength.

First-principles study of MoS2, phosphorene and graphene based single electron transistor for gas sensing applications

Abstract: Two dimensional single crystals like graphene, transition metal dichalcogenides, phosphorene, etc can be useful for sensing applications due to their enhanced surface to volume ratio A single electron transistor (SET) device made of such materials is proposed here as a futuristic low power device prototype for sensing purposes The operation and performance of these SET devices are investigated for the first time using Density functional theory based Ab-initio calculations to understand their relative sensitivities towards sensing different gas molecules The adsorption of CO, CO2, NH3 and NO2 on monolayers of graphene, MoS2 and phosphorene are investigated to find their most stable configurations and relative orientations on the host layers The structural and electronic properties of the host layers have been found to be unaffected as a result of the adsorption processes Phosphorene offers highest strength of physio-adsorption for all these molecules, indicating its superiority than the other two materials It is observed that Phosphorene and MoS2 are additionally sensitive towards the N-based molecules and magnetism could be induced in the presence of a paramagnetic molecule Present results indicate that the charge stability diagram of the SET is unique for a specific gas molecule on the Two-dimensional (2D) layer and this is sensitive up to the addition/removal of a single molecule from the island The wide temperature range of operation, extreme detection sensitivity and the versatility of the 2D materials for gas sensing make these SET devices very powerful candidates for practical application

Recent advances in amplify-and-forward two-hop relaying

Abstract: In this article we review an important class of wireless cooperation protocols known as amplify-and-forward relaying. One or more low-complexity relay nodes assist the communication between sources and destinations without having to decode the signal. This makes AF relaying transparent to modulation and coding of the source/destination communication protocol. It is therefore a highly flexible technology that also qualifies for application in heterogeneous networks comprising many nodes of different complexity or even standards. Recently, two-way relaying was introduced, which is readily combined with AF relaying. It is a spectrally efficient protocol that allows for bidirectional communication between sources and destinations. In order to investigate the potential of wireless AF relaying, we introduce three distributed network scenarios that differ in the amount of cooperation between nodes. New challenges arise in those networks, and we discuss approaches to overcome them. For the most general case of a completely distributed system, we present coherent relaying solutions that offer a distributed spatial multiplexing gain even for single-antenna nodes. Based on real-world experiments, we validate the feasibility of all schemes in our laboratory.

Analytic bond-order potential for bcc and fcc iron—comparison with established embedded-atom method potentials

Abstract: A new analytic bond-order potential for iron is presented that has been fitted to experimental data and results from first-principles calculations. The angular-dependent functional form allows a proper description of a large variety of bulk, surface and defect properties, including the Bain path, phonon dispersions, defect diffusivities and defect formation energies. By calculating Gibbs free energies of body-centred cubic (bcc) and face-centred cubic (fcc) iron as a function of temperature, we show that this potential is able to reproduce the transitions from α-iron to γ-iron and δ-iron before the melting point. The results are compared to four widely used embedded-atom-method potentials for iron.

First insight into the genome of an uncultivated crenarchaeote from soil.

Abstract: Molecular phylogenetic surveys based on the characterization of 16S rRNA genes have revealed that soil is an environment particularly rich in microbial diversity. A clade of crenarchaeota (archaea) has frequently been detected among many other novel lineages of uncultivated bacteria. In this study we have initiated a genomic approach for the characterization of uncultivated microorganisms from soil. We have developed a procedure based on a two-phase electrophoresis technique that allows the fast and reliable purification of concentrated and clonable, high molecular weight DNA. From this DNA we have constructed complex large-insert genomic libraries. Using archaea-specific 16S rRNA probes we have isolated a 34 kbp fragment from a 900 Mbp fosmid library of soil DNA. The clone contained a complete 16S/23S rRNA operon and 17 genes encoding putative proteins. Phylogenetic analyses of the rRNA genes and of several protein encoding genes (e.g. DNA polymerase, FixAB, glycosyl transferase) confirmed the specific affiliation of the genomic fragment with the non-thermophilic clade of the crenarchaeota. Content and structure of the genomic fragment indicated that the archaea from soil differ significantly from their previously studied uncultivated marine relatives. The protein encoding genes gave the first insights into the physiological potential of these organisms and can serve as a basis for future genomic and functional genomic studies.