Berufliche Weiterbildung für Arbeitslose - ein Weg zurück in Beschäftigung? : Analyse einer Abgängerkohorte des Jahres 1986 aus Maßnahmen zur Fortbildung und Umschulung mit der ergänzten IAB-Beschäftigtenstichprobe 1975-1990 (Further vocational training for the unemployed - a way back to employment? : analysis of a cohort of people completing further training and retraining measures in 1986, using the extended IAB employment sample 1975-1990)

"The success of further vocational training and retraining is evaluated in this paper on the basis of a comparison group approach and using a new data source. For this the IAB employment sample was extended to include details about further training and retraining measures. For a cohort of people completing further training or retraining measures in 1986 the authors analyse as an example the effects on the individual labour market success between 1986 and 1990. The access requirements for these measures are reconstructed for the participants of the further training and retraining measures and for a control group. The control group is made up of people who were employed for a short time in the period 1983-1986 and, like the participants in the further training and retraining measures, previously claimed unemployment benefit. By means of a hierarchical matching method, statistical doubles are found for about 90% of all the participants in the further training and retraining measures. On the basis of 985 pairs of participants and comparison persons, event-analytical estimations are made concerning the return to employment subject to social security contributions after a course of further training or retraining or after the period of short-term employment. In addition the determinants of the duration of this first phase of employment are estimated. The results suggest that in the period under examination participation in further training or retraining has a weak positive employment effect for individuals who were unemployed before beginning the training measure if they take up work immediately after the measure. However, further training and retraining have a significantly negative effect - seen in relation to the control group - on remaining in employment. The authors interpret this as a consequence of employment-relevant deficits that can not be influenced by further training or retraining. Further detailed evaluation studies with (extended) business statistics can help to clarify this." (Author's abstract, IAB-Doku) ((en))berufliche Reintegration, Beschäftigungseffekte, Weiterbildungsförderung - Erfolgskontrolle, Arbeitslose, IAB-Beschäftigtenstichprobe

Die IAB-Beschäftigtenstichprobe 1975-1995

Die Verfasser stellen die neue Version der IAB-Beschäftigtenstichprobe dar, wie sie im Zentralarchiv für Empirische Sozialforschung vorliegt. Sie geben eine Überblick über den Datenbestand, behandeln die Anonymisierung der vorhandenen Merkmale und demonstrieren anhand eines Anwendungsbeispiels (Mobilität in Beschäftigung und aus Beschäftigung in Arbeitslosigkeit) die Leistungsfähigkeit der Datenbasis für detaillierte Analysen. Die IAB-Beschäftigtenstichprobe wird als reichhaltige Datenquelle bewertet, deren Analysepotential durch die gesetzlich geforderten Anonymisierungen nicht beeinträchtigt wird. (ICE

Laser powder bed fusion of WE43 in hydrogen-argon-gas atmosphere

Growing demand for individual and especially complex parts with emphasis on biomedical or lightweight applications enhances the importance of laser powder bed fusion. Magnesium alloys offer both biocompatibility and low density, but feature a very high melting point of oxide layers while the evaporation temperature of pure magnesium is much lower. This impedes adequate part quality and process reproducibility. To weaken this oxide layer and enhance processability, a 2 %-hydrogen-argon-gas atmosphere was investigated. A machine system was modified to the use of the novel inert gas to determine the influence of gas atmosphere on hollow cuboids and solid cubes. While processing a 20.3 % decrease in structure width and 20.6 % reduction in standard deviation of the cuboids was determined. There was no significate influence on relative density of solid cubes although eight of the ten highest density specimen were fabricated with the hydrogen addition. © 2020 The Authors. Published by Elsevier B.V

Photon correlation spectroscopy with heterodyne mixing based on soft-x-ray magnetic circular dichroism

Many magnetic equilibrium states and phase transitions are characterized by fluctuations. Such magnetic fluctuation can in principle be detected with scattering-based x-ray photon correlation spectroscopy (XPCS). However, in the established approach of XPCS, the magnetic scattering signal is quadratic in the magnetic scattering cross section, which results not only in often prohibitively small signals but also in a fundamental inability to detect negative correlations (anticorrelations). Here, we propose to exploit the possibility of heterodyne mixing of the magnetic signal with static charge scattering to reconstruct the first-order (linear) magnetic correlation function. We show that the first-order magnetic scattering signal reconstructed from heterodyne scattering now directly represents the underlying magnetization texture. Moreover, we suggest a practical implementation based on an absorption mask rigidly connected to the sample, which not only produces a static charge scattering signal but also eliminates the problem of drift-induced artificial decay of the correlation functions. Our method thereby significantly broadens the range of scientific questions accessible by magnetic x-ray photon correlation spectroscopy

Development of a laser powder bed fusion process tailored for the additive manufacturing of high-quality components made of the commercial magnesium alloy WE43

Additive manufacturing (AM) has become increasingly important over the last decade and the quality of the products generated with AM technology has strongly improved. The most common metals that are processed by AM techniques are steel, titanium (Ti) or aluminum (Al) alloys. However, the proportion of magnesium (Mg) in AM is still negligible, possibly due to the poor processability of Mg in comparison to other metals. Mg parts are usually produced by various casting processes and the experiences in additive manufacturing of Mg are still limited. To address this issue, a parameter screening was conducted in the present study with experiments designed to find the most influential process parameters. In a second step, these parameters were optimized in order to fabricate parts with the highest relative density. This experiment led to processing parameters with which specimens with relative densities above 99.9% could be created. These highdensity specimens were then utilized in the fabrication of test pieces with several different geometries, in order to compare the material properties resulting from both the casting process and the powder bed fusion (PBF-LB) process. In this comparison, the compositions of the occurring phases and the alloys’ microstructures as well as the mechanical properties were investigated. Typically, the microstructure of metal parts, produced by PBF-LB, consisted of much finer grains compared to as-cast parts. Consequently, the strength of Mg parts generated by PBF-LB could be further increased. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

In vivo investigation of open-pored magnesium scaffolds LAE442 with different coatings in an open wedge defect

The magnesium alloy LAE442 showed promising results as a bone substitute in numerous studies in non-weight bearing bone defects. This study aimed to investigate the in vivo behavior of wedge-shaped open-pored LAE442 scaffolds modified with two different coatings (magnesium fluoride (MgF2, group 1)) or magnesium fluoride/calcium phosphate (MgF2/CaP, group 2)) in a partial weight-bearing rabbit tibia defect model. The implantation of the scaffolds was performed as an open wedge corrective osteotomy in the tibia of 40 rabbits and followed for observation periods of 6, 12, 24, and 36 weeks. Radiological and microcomputed tomographic examinations were performed in vivo. X-ray microscopic, histological, histomorphometric, and SEM/EDS analyses were performed at the end of each time period. µCT measurements and X-ray microscopy showed a slight decrease in volume and density of the scaffolds of both coatings. Histologically, endosteal and periosteal callus formation with good bridging and stabilization of the osteotomy gap and ingrowth of bone into the scaffold was seen. The MgF2 coating favored better bridging of the osteotomy gap and more bone-scaffold contacts, especially at later examination time points. Overall, the scaffolds of both coatings met the requirement to withstand the loads after an open wedge corrective osteotomy of the proximal rabbit tibia. However, in addition to the inhomogeneous degradation behavior of individual scaffolds, an accumulation of gas appeared, so the scaffold material should be revised again regarding size dimension and composition

In vivo investigation of open-pored magnesium scaffolds LAE442 with different coatings in an open wedge defect

The magnesium alloy LAE442 showed promising results as a bone substitute in numerous studies in non-weight bearing bone defects. This study aimed to investigate the in vivo behavior of wedge-shaped open-pored LAE442 scaffolds modified with two different coatings (magnesium fluoride (MgF2, group 1)) or magnesium fluoride/calcium phosphate (MgF2/CaP, group 2)) in a partial weight-bearing rabbit tibia defect model. The implantation of the scaffolds was performed as an open wedge corrective osteotomy in the tibia of 40 rabbits and followed for observation periods of 6, 12, 24, and 36 weeks. Radiological and microcomputed tomographic examinations were performed in vivo. X-ray microscopic, histological, histomorphometric, and SEM/EDS analyses were performed at the end of each time period. µCT measurements and X-ray microscopy showed a slight decrease in volume and density of the scaffolds of both coatings. Histologically, endosteal and periosteal callus formation with good bridging and stabilization of the osteotomy gap and ingrowth of bone into the scaffold was seen. The MgF2 coating favored better bridging of the osteotomy gap and more bone-scaffold contacts, especially at later examination time points. Overall, the scaffolds of both coatings met the requirement to withstand the loads after an open wedge corrective osteotomy of the proximal rabbit tibia. However, in addition to the inhomogeneous degradation behavior of individual scaffolds, an accumulation of gas appeared, so the scaffold material should be revised again regarding size dimension and composition

Magnesium Alloys for Open-Pored Bioresorbable Implants

If bone defects occur, the body’s own healing mechanism can close them below a critical size; for larger defects, bone autografts are used. These are typically cut from the same person’s hip in a second surgery. Consequently, the risk of complications, such as inflammations, rises. To avoid the risks resulting from the second surgery, absorbable, open-pored implants can be used. In the present study, the suitability of different magnesium alloys as absorbable porous bone substitute material has been investigated. Using the investment casting process with its design flexibility, the implant’s structure can be adapted to the ideal pore geometry with respect to bone ingrowth behavior. Different magnesium alloys (Mg-La2, LAE442, and ZX61) were studied and rated in terms of their degradation rate, bone ingrowth behavior, biocompatibility, and resorbability of the individual alloying elements