97 research outputs found

    Influence of the process parameters on the grinding result in continuous generating grinding of cutting tools

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    Continuous generating grinding processes have largely replaced discontinuous profile grinding processes in gear manufacturing due to their higher productivity. On order to transfer the advantage of the productivity benefits of this process to tool grinding, the continuous generating grinding was adapted to the manufacture of cutting tools. However, this novel approach of using continuous generating grinding processes for tool grinding has not been widely investigated. Therefore, the aim of this study is to investigate the influence of cutting speed, feed and radial depth of cut on the process result and thus to generate initial knowledge for the process design. Subsequently, the influence of these parameters on the grinding worm wear as well as on the cutting edge quality and surface properties of the ground milling tools are investigated. The results show that an increase of the radial depth of cut leads to a reduction of the process time by the factor of four without significantly influencing the wear of the grinding worm tooth. Furthermore, an increase of the cutting speed only leads to an increase in the initial wear of the grinding worm after the dressing process. For this reason, the cutting speed offers the potential to further increase the productivity of the process. The microgeometry of the cutting edge of the ground milling tool is mainly affected by the feed and the macro geometry by the feed and radial depth of cut

    On the current practice of New Business Development in the German chemical industry

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    The results of a survey on the practice of new business development conducted in 17 chemical industry companies and related business sectors, such as service providers, are presented in this article. The objectives and organizational setup of New Business Development were found to be exceptionally heterogeneous and to cover a broad spectrum. The differentiation between New Business Development and Innovation Management was also not consistent between the companies. All the companies underlined the importance of technical and scientific know-how for new business development staff, but also emphasized the relevance of interdisciplinary competencies at the interface between natural science and business. Small companies follow a rather opportunistic New Business Development approach without dedicated organizational structures. Larger companies, on the other hand, employ a Stage-Gate process and largely derive their ideas from megatrends. Differences between small and larger companies are discussed in the article at hand

    Competition of Dzyaloshinskii-Moriya and higher-order exchange interactions in Rh/Fe atomic bilayers on Ir(111)

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    Using spin-polarized scanning tunneling microscopy and density functional theory we demonstrate the occurrence of a novel type of noncollinear spin structure in Rh/Fe atomic bilayers on Ir(111). We find that higher-order exchange interactions depend sensitively on the stacking sequence. For fcc-Rh/Fe/Ir(111) frustrated exchange interactions are dominant and lead to the formation of a spin spiral ground state with a period of about 1.5 nm. For hcp-Rh/Fe/Ir(111) higher-order exchange interactions favor a double-row wise antiferromagnetic or "uudd" state. However, the Dzyaloshinskii- Moriya interaction at the Fe/Ir interface leads to a small angle of about 4{\deg} between adjacent magnetic moments resulting in a canted "uudd" ground state

    Detecting Process Anomalies in the GMAW Process by Acoustic Sensing with a Convolutional Neural Network (CNN) for Classification

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    Today, the quality of welded seams is often examined off-line with either destructive or non-destructive testing. These test procedures are time-consuming and therefore costly. This is especially true if the welds are not welded accurately due to process anomalies. In manual welding, experienced welders are able to detect process anomalies by listening to the sound of the welding process. In this paper, an approach to transfer the “hearing” of an experienced welder into an automated testing process is presented. An acoustic measuring device for recording audible sound is installed for this purpose on a fully automated welding fixture. The processing of the sound information by means of machine learning methods enables in-line process control. Existing research results until now show that the arc is the main sound source. However, both the outflow of the shielding gas and the wire feed emit sound information. Other investigations describe welding irregularities by evaluating and assessing existing sound recordings. Descriptive analysis was performed to find a connection between certain sound patterns and welding irregularities. Recent contributions have used machine learning to identify the degree of welding penetration. The basic assumption of the presented investigations is that process anomalies are the cause of welding irregularities. The focus was on detecting deviating shielding gas flow rates based on audio recordings, processed by a convolutional neural network (CNN). After adjusting the hyperparameters of the CNN it was capable of distinguishing between different flow rates of shielding gas

    Mechanisms of action and processes of yoga-based group intervention for inpatients with schizophrenia spectrum disorders–A longitudinal qualitative study

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    Background: Research exploring the effects of yoga therapy (YT) on individuals with schizophrenia spectrum disorders (SSD) is scarce. Therefore, the current study aimed to explore possible mechanisms of actions and processes, as well as adverse effects of a novel yoga-based group intervention (YoGI) for in-patients with SSD in a German university hospital setting. Material and methods: A longitudinal qualitative study was integrated into a rater-blinded randomized controlled trial, exploring the impact of a 4-week YoGI as add-on treatment. In-depth interviews were conducted with participants receiving YoGI (n = 19) in addition to treatment as usual (TAU) and a control group (n = 14) which only received TAU. Interviews were conducted at baseline (n = 33) and 4 weeks post-intervention (N = 28) to assess the participant's experiences and how they changed over time. The interviews (N = 61) were audio-taped, translated, coded, and analyzed by means of inductive thematic analysis. Separate case summaries were prepared for each participant to analyze longitudinal changes within subjects. The research team members collaboratively discussed the final list of themes and subcodes. Rater-based questionnaires, such as the Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale for Schizophrenia (CDSS), and Personal and Social Performance Scale (PSP) were administered at baseline to assess clinical outcomes. Results: At baseline, participants reported a desire to improve their stress- and symptom management. A minority of participants expressed reservations toward yoga, and several psychosocial barriers were named, including worries about symptom exacerbation. At post-intervention, four mechanisms of change became evident from the interviews: (1) acquiring competence in relaxation, (2) increased interoceptive awareness, (3) feeling connected, and (4) a sense of spiritual wellbeing. A small number of participants reported difficulties with YoGI. Conclusion: Generally, YoGI positively influenced participants' experiences of their inpatient stay, regarding distress, self- and body awareness, social connectedness, and spiritual wellbeing. However, participants also illuminated necessary adjustments to improve the intervention. YoGI will therefore be adapted and further developed in an iterative process based on a participant involvement approach. The efficacy regarding outcomes and processes needs to be investigated in a future larger-scaled randomized controlled trial

    Writing and Deleting Single Magnetic Skyrmions

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    Topologically nontrivial spin textures have recently been investigated for spintronic applications. Here, we report on an ultrathin magnetic film in which individual skyrmions can be written and deleted in a controlled fashion with local spin-polarized currents from a scanning tunneling microscope. An external magnetic field is used to tune the energy landscape, and the temperature is adjusted to prevent thermally activated switching between topologically distinct states. Switching rate and direction can then be controlled by the parameters used for current injection. The creation and annihilation of individual magnetic skyrmions demonstrates the potential for topological charge in future information-storage concepts

    Prevalence, predictors and types of unpleasant and adverse effects of meditation in regular meditators: international cross-sectional study

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    Background: Meditation is commonly implemented in psychological therapies since the ‘third wave’ of cognitive–behavioural therapy has increased the focus on mindfulness-based interventions. Although extensive research literature demonstrates its benefits, little is known about potential adverse effects. Aims: The aim of this study is to report the prevalence, type and severity of particularly unpleasant meditation-related experiences in the largest cross-sectional study on this topic to date, with 1370 regular meditators. Method: The participants were asked whether they ever encountered particularly unpleasant experiences as a result of their meditation experience. For the first time, the type and severity of those experiences were assessed and the association with several predictors, such as pre-existing mental disorders, were explored via logistic and linear regression. Results: Similar to previous studies, 22% of participants (95% CI 20–24) reported having encountered unpleasant meditation-related experiences, and 13% of participants (95% CI 3–5) reported experiences that were categorised as adverse. Those were mostly of affective, somatic and cognitive nature. Unpleasant meditation-related experiences were more likely to occur in participants with pre-existing mental illnesses (P = 0.000, 95% CI 1.25–2.12). Conclusions: This study demonstrates that unpleasant meditation-related experiences are prevalent among meditators and, to a relevant extent, severe enough to warrant further scientific inquiry. Longitudinal studies are needed to examine whether the unpleasant meditation-related experiences are merely negative and thus should be avoided, or are an inherent part of the contemplative path

    Compassion-based approaches:a systematic review of their effectiveness and acceptability in schizophrenia spectrum disorders

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    The purpose of this systematic literature review is to provide an exhaustive summary of current research to explore the prospects of compassion-based approaches in treating persons with Schizophrenia Spectrum Disorders (SSD). Thereby, studies investigating the relationship between clinical parameters and self-compassion in SSD, as well as the acceptability, feasibility, and effects of compassion-based approaches for individuals with SSD were considered. The review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and checklist. Eight studies were included for qualitative synthesis. The results indicate an important role of self-compassion for several clinical parameters, including negative associations to positive symptoms, negative symptoms, cognitive disorganization, and emotional distress. All studies reported good acceptability and feasibility. Regarding the clinical effectiveness of compassion-based approaches, a variety of clinical benefits, such as improvements of mood, affect regulation, positive symptoms, negative symptoms, cognitive disorganization, and variables relating to psychological recovery were found in individuals with SSD. It is concluded that compassion-based approaches are a promising form of intervention in the treatment of SSD. However, further research, especially randomized controlled trials, in this field is needed to understand the full potential of compassion-based approaches for individuals with SSD.</p
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