Optical Spin Noise of a Single Hole Spin Localized in an (InGa)As Quantum Dot

We advance spin noise spectroscopy to the ultimate limit of single spin detection. This technique enables the measurement of the spin dynamic of a single heavy hole localized in a flat (InGa)As quantum dot. Magnetic field and light intensity dependent studies reveal even at low magnetic fields a strong magnetic field dependence of the longitudinal heavy hole spin relaxation time with an extremely long $T_1$ of $\ge$ 180 $\mu$s at 31 mT and 5 K. The wavelength dependence of the spin noise power discloses for finite light intensities an inhomogeneous single quantum dot spin noise spectrum which is explained by charge fluctuations in the direct neighborhood of the quantum dot. The charge fluctuations are corroborated by the distinct intensity dependence of the effective spin relaxation rate

Two-Scale Optimization of Graded Lattice Structures respecting Buckling on Micro- and Macroscale

Interest in components with detailed structures increased with the progress in advanced manufacturing techniques in recent years. Parts with graded lattice elements can provide interesting mechanical, thermal, and acoustic properties compared to parts where only coarse features are included. One of these improvements is better global buckling resistance of the component. However, thin features are prone to local buckling. Normally, analyses with high computational effort are conducted on high-resolution finite element meshes to optimize parts with good global and local stability. Until recently, works focused only on either global or local buckling behavior. We use two-scale optimization based on asymptotic homogenization of elastic properties and local buckling behavior to reduce the effort of full-scale analyses. For this, we present an approach for concurrent local and global buckling optimization of parameterized graded lattice structures. It is based on a worst-case model for the homogenized buckling load factor, which acts as a safeguard against pure local buckling. Cross-modes residing on both scales are not detected. We support our theory with numerical examples and validations on dehomogenized designs, which show the capabilities of our method, and discuss the advantages and limitations of the worst-case model.Comment: submitted to Structural and Multidisciplinary Optimizatio

Combined Eccentric-Isokinetic and Isoinertial Training Leads to Large Ring-Specific Strength Gains in Elite Gymnasts.

In male elite gymnastics, lately, eccentric training is often used to improve the maximum specific strength of static elements on rings. Therefore, in this study, we aimed to investigate the effects of a three-week, gymnastic-specific, eccentric-isokinetic (0.1 m/s) cluster training with a change of stimulus after three of six training sessions (eccentric-isokinetic with additional load) on a computer-controlled training device on the improvement of the elements swallow and support scale on rings. Maximum strength and strength endurance in maintaining the static positions of ten international elite male gymnasts were determined on a weekly basis. After three weeks of training, specific maximum strength and strength endurance increased significantly (strength: swallow: +8.72%, p < 0.001; support scale: 8.32%, p < 0.0001; strength endurance: swallow: +122.36%; p = 0.02; Support Scale: +93.30%; p = 0.03). Consequently, top gymnasts can considerably improve ring-specific strength and strength endurance in only three weeks. The separate analysis of the effects of both eccentric-isokinetic training modalities showed that efficiency might even be increased in future training interventions. We suggest using this type of training in phases in which the technical training load is low and monitoring the adaptations in order to compile an individually optimized training after an intervention

The rise of spin noise spectroscopy in semiconductors: From acoustic to GHz frequencies

This article gives an overview on the advance of spin noise spectroscopy (SNS) in semiconductors in the past 8 years from the first measurements in bulk n-GaAs [Oestreich et al., Phys. Rev. Lett. 95, 216603 (2005)] up to the recent achievement of optical detection of the intrinsic spin fluctuations of a single hole confined in an individual self-assembled quantum dot [Dahbashi et al., arXiv:1306.3183 (2013)]. We discuss the general technical implementation of optical SNS and the invaluable profit of the introduction of real-time fast Fourier transform analysis into the data acquisition. By now, the full spin dynamic from the milli- to picosecond timescales can be addressed by SNS and the technique quickly strides ahead to enable real quantum non-demolition measurements in semiconductors. Spin noise spectra recorded in 2005 in bulk n-GaAs with approximately 109 electron spins (Oestreich et al.) and 2013 (Dahbashi et al.) for a single hole spin. The integration time for the latter is more than a factor of 40 shorter due to the significant advances in the measurement technique

An Approach For Analysis Of Human Interaction With Worker Assistance Systems Based On Eye Tracking And Motion Capturing

Human behavior in production systems influences productivity, product quality, work safety and overall process performance. To guide human behavior, digital worker assistance systems can be used to support cognitive decision tasks and sensory perception tasks. In doing so, the design of the assistance systems affects user experience and work results. To optimize and develop human-centric productions systems, data on human behavior and interaction with manufacturing equipment must be collected and analyzed. This analysis is expected to yield benefits regarding process monitoring, quality assurance, user experience and ergonomics. In addition, the results could be used for training purposes to monitor skill improvements. This paper presents a framework for data acquisition and analysis of human interaction with digital worker assistance systems. In addition to the overall system architecture, the individual development steps are discussed. An eye tracking device and a motion capturing camera are used for data collection and provide live information about human behavior in conjunction with a digital worker assistance system. The data is stored in a database and analyzed by custom analysis algorithms. The results are displayed in a dashboard application and show that the presented framework with eye tracking and motion capturing is suitable for the analysis of human interaction with worker assistance systems

A Systematic Literature Review of Blockchain-Based Traceability Solutions

Blockchain technology shows great potential in providing object-related end-to-end traceability in complex multitiered supply networks. However, the first systematic literature reviews indicate the immaturity of current blockchain-based solutions and highlight difficulties in assessing their object traceability capabilities. Therefore, this paper provides a systematic literature review of blockchain-based traceability solutions and analyses their object-related mapping capabilities. As the systematic literature reveals, the vast majority of the identified traceability solutions deal with low-complexity architectures without the ability to map objects' compositional changes. Here, food and medical supply chains represent the most dominant domains. Supply chains in the automotive and manufacturing domain place the highest requirements for mapping object-related supply chain events. In this context, solutions incorporating the tokenisation of objects show the most advanced object-related mapping capabilities. However, the identified advanced solutions show limitations regarding their ability to map object deletions, aggregations, and disaggregations. Furthermore, current blockchain-based traceability solutions provide only limited validations based on industrial case studies

Innovation Management in Manufacturing - A Study on Industrial Application, Deficits, and Opportunities

Manufacturing companies are constantly pressured to innovate in an increasingly complex and discontinuous environment. In addition to developing new products and product features, innovation management in manufacturing has become necessary to ensure the competitiveness of technologies and processes in the context of digitalization, human centricity, sustainability and resilience (Industry 5.0). In the study, presented in this paper, companies from various industries participated in an online survey on their approach to incremental and radical innovation in manufacturing and the associated innovation management. In the study, more than 50 participants provide insight into the innovation management of their manufacturing unit and identify concrete fields of action as well as challenges in the areas of technology, organization and people. The study results are intended to provide manufacturing innovation managers with an overview of the challenges, deficits and potentials of innovation management in manufacturing and to help them identify and describe challenges in their organization

Interplay of Electron and Nuclear Spin Noise in n -Type GaAs

We present spin-noise spectroscopy measurements on an ensemble of donor-bound electrons in ultrapure GaAs:Si covering temporal dynamics over 6 orders of magnitude from milliseconds to nanoseconds. The spin-noise spectra detected at the donor-bound exciton transition show the multifaceted dynamical regime of the ubiquitous mutual electron and nuclear spin interaction typical for III-V-based semiconductor systems. The experiment distinctly reveals the finite Overhauser shift of an electron spin precession at zero external magnetic field and a second contribution around zero frequency stemming from the electron spin components parallel to the nuclear spin fluctuations. Moreover, at very low frequencies, features related with time-dependent nuclear spin fluctuations are clearly resolved making it possible to study the intricate nuclear spin dynamics at zero and low magnetic fields. The findings are in agreement with the developed model of electron and nuclear spin noise. © 2015 American Physical Society