Direct Measurement of the g-Factor of Composite Fermions

The activation gap $\Delta$ of the fractional quantum Hall states at constant fillings $\nu =2/3$ and 2/5 has been measured as a function of the perpendicular magnetic field $B$. A linear dependence of $\Delta$ on $B$ is observed while approaching the spin polarization transition. This feature allows a direct measurement of the $g$-factor of composite fermions which appears to be heavily renormalized by interactions and strongly sensitive to the electronic filling factor.Comment: 4 pages, 4 figures Changed content: Fokus more on g-factors (and less on other details

Searching for molecular outflows in Hyper-Luminous Infrared Galaxies

We present constraints on the molecular outflows in a sample of five Hyper-Luminous Infrared Galaxies using Herschel observations of the OH doublet at 119 {\mu}m. We have detected the OH doublet in three cases: one purely in emission and two purely in absorption. The observed emission profile has a significant blueshifted wing suggesting the possibility of tracing an outflow. Out of the two absorption profiles, one seems to be consistent with the systemic velocity while the other clearly indicates the presence of a molecular outflow whose maximum velocity is about ~1500 km/s. Our analysis shows that this system is in general agreement with previous results on Ultra-luminous Infrared Galaxies and QSOs, whose outflow velocities do not seem to correlate with stellar masses or starburst luminosities (star formation rates). Instead the galaxy outflow likely arises from an embedded AGN.Comment: Accepted for publication in MNRAS. 13 pages, 11 figures, 4 table

The degradation of MgB2 under ambient environment

The superconductivities of samples prepared by several procedures were found to degrade under ambient environment. The degradation mechanism was studied by measuring the change of surface chemical composition of dense MgB2 pellets (prepared by hot isostatic pressure, HIPed) under atmospheric exposure using X-ray Photoelectron Spectroscopy (XPS). Results showed that samples with poor connectivity between grains and with smaller grain sizes degrade with time when exposed to ambient conditions. In these samples, the Tc did not change with time, but the superconducting transition became broader and the Meissner fraction decreased. In contrast, our well-sintered and the HIPed samples remained stable for several months under ambient condition. The degradation was found to be related to surface decomposition as observed by XPS. We observed the formation of oxidized Mg, primarily in the form of a Mg hydroxide, the increase of C and O contents, and the reduction of B concentration in the surface layer of MgB2 samples.Comment: 15 pages, 3 figure

FEM-based comparison of models to predict dynamic recrystallization during orthogonal cutting of AISI 4140

Machining processes induce a thermo-mechanical load collective on the surface layer, which leads to grain refinement of varying depths depending on several factors apart from the workpiece. The size relation of the cutting edge radius to the cutting depth (relative roundness) as well as the cutting edge microgeometry influence the generation of nanocrystalline layers. In this work several models to predict dynamic recrystallization during orthogonal cutting of AISI 4140 are compared using 2D FEM-models considering both, relative roundness and cutting edge microgeometry

Milling parameter and tool wear dependent surface quality in micro-milling of brass

Short life-time and high tool costs still remain major constraints for the micro-milling process. Understanding the wear mechanisms and their effects on the workpiece quality is essential for efficient tool usage. Usually, wear increases the cutting forces and reduces the emerging surface quality during the micro-milling process. Due to high tool costs, cutting parameters are usually chosen for optimal tool lifetime and/or process time rather than optimal surface quality. The scope of this paper is to investigate the correlation of the process parameters, strategy and wear status of the tool on the resulting surface topography. To reach this goal, micro-milling experiments were conducted, in which several grooves were milled using two end milling tools, new and worn, with a diameter of 1.5 mm and four cutting edges. The cutting speed and feed were varied, as well as the cutting direction. Brass was chosen as workpiece material to ensure a constant wear state of the tools during the experiments. During the cutting process the process forces were recorded and examined for their magnitude and frequency response. Furthermore, the grooves were analyzed optically for their surface roughness. The roughness shows in most cases slightly higher values for the specimen manufactured with the worn tool than the ones done with the new tool. The biggest influence on the surface roughness results from the feed rate, while cutting speed and milling strategy have a smaller influence. The measured cutting forces show similar tendencies, than the resulting surface roughness. The results show also a significant influence of tool wear on the vibration behavior during the process, while the influence of feed rate is mostly negligible. This results partly from the greater tool runout and bigger deviation of the cutting edges

Molecular screening of microorganisms associated with discolored wood in dead European beech trees suffered from extreme drought event using next generation sequencing

Drought events weaken trees and make them vulnerable to attacks by diverse plant pathogens. Here, we propose a molecular method for fast screening of microorganisms associated with European beech decline after an extreme drought period (2018) in a forest of Thuringia, Germany. We used Illumina sequencing with a recent bioinformatics approach based on DADA2 to identify archaeal, bacterial, and fungal ASVs (amplicon sequence variants) based on bacterial and archaeal 16S and fungal ITS genes. We show that symptomatic beech trees are associated with both bacterial and fungal plant pathogens. Although the plant pathogen sequences were detected in both discolored and non-discolored wood areas, they were highly enriched in the discolored wood areas. We show that almost each individual tree was associated with a different combination of pathogens. Cytospora spp. and Neonectria coccinea were among the most frequently detected fungal pathogens, whereas Erwinia spp. and Pseudomonas spp. were the dominant bacterial plant pathogens. We demonstrate that bacterial plant pathogens may be of major importance in beech decline

Purification and analytical characterization of an anti- CD4 monoclonal antibody for human therapy

A purification process for the monclonal anti-CD4 antibody MAX.16H5 was developed on an analytical scale using (NH&SO, precipitation, anion-exchange chromatography on MonoQ or Q-Sepharose, hydrophobic interaction chromatography on phenyl- Sepharose and gel filtration chromatography on Superdex 200. The purification schedule was scaled up and gram amounts of MAX.16H5 were produced on corresponding BioPilot columns. Studies of the identity, purity and possible contamination by a broad range of methods showed that the product was highly purified and free from contaminants such as mouse DNA, viruses, pyrogens and irritants. Overall, the analytical data confirm that the monoclonal antibody MAX.16H5 prepared by this protocol is suitable for human therapy

Influence of anisotropy of additively manufactured AlSi10Mg parts on chip formation during orthogonal cutting

Anisotropic behavior of metals can influence manufacturing processes including acting thermo-mechanical loads and resulting surface layer states. In additive manufacturing, the build-up direction influences material states like microstructure, density distribution and stress fields, possibly leading to anisotropic behavior. In this work, additively manufactured AlSi10Mg is characterized in tension tests in order to determine the anisotropic material deformation behavior due to the build-up procedure. This was implemented in 2D cutting simulations using finite element method. Additionally, orthogonal cutting experiments were performed in order to determine process forces and chip formation, which finally were used in order to validate simulations

Hybrid protoneutron stars with the MIT bag model

We study the hadron-quark phase transition in the interior of protoneutron stars. For the hadronic sector, we use a microscopic equation of state involving nucleons and hyperons derived within the finite-temperature Brueckner-Bethe-Goldstone many-body theory, with realistic two-body and three-body forces. For the description of quark matter, we employ the MIT bag model both with a constant and a density-dependent bag parameter. We calculate the structure of protostars with the equation of state comprising both phases and find maximum masses below 1.6 solar masses. Metastable heavy hybrid protostars are not found.Comment: 12 pages, 9 figures submitted to Phys. Rev.