In-situ characterization of tool temperatures using in-tool integrated thermoresistive thin-film sensors

Metal cutting is characterized by high temperatures at the tool-workpiece interface. Although valuable information could be provided by the temperature values, their direct measurement still presents a challenge due to the high contact pressure and the inaccessibility of the process kinematic. In this research work, the current state of thin-film sensors for measuring temperatures on the chip-tool interface has been analyzed with a focus on the measuring phenomena: thermoelectricity and thermoresistivity. Thin-film sensors placed on the cutting tools in or close to the tool-chip contact area are expected to obtain accurate temperature information at the expense of a short lifetime. New insights into thin-film sensors manufacturing, design and calibration are presented, and a new concept of a three-point thermoresistive thin-film sensor is proposed. During orthogonal cutting tests the workpiece deformations were measured through high-speed imaging and the process temperatures were measured with thin-film sensors. In order to validate the temperatures and to obtain the temperature distribution on the cutting edge, Finite Element simulations were carried out. Finally, the potential of using cutting tools with integrated thin-film sensors for in-situ characterization is investigated and a statement for its limitations and potential applications is given

NaturalWalk: An Anatomy-based Synthesizer for Human Walking Motions

We present a novel data-driven approach for synthesizing human gait motions with individual style characteristics and natural appearance. Our approach is based on the concept of a motion signature that captures the essential characteristic of an individual walking motion. For each joint angle our motion model consists of a shape template and feature functions that describe the variation of that shape with the stride length. For the synthesis of a walking motion, the feature functions are evaluated for a desired stride length. Then the templates are adapted to match the computed features and used as progressions for the joint angles of the skeleton. We demonstrate our data driven approach using motion data captured from 12 individuals. We report on an experiment showing that the synthesized motions have a natural appearance and maintain the individual style.:1. Introduction 2. Related Work 3. Preliminaries 3.1 Mathematics of motion 3.2 Walking motions 4. Data acquisition and analysis 5. Shape templates and feature functions 5.1 Definition of template functions 5.2 Continuous representation of template functions 5.3 Building the feature functions 6. Motion Generation 6.1 Adaption of template functions 6.2 Computing the poses 7 Experimental Results 7.1 Numerical Evaluation 7.2 User Study Acknowledgment Reference

Hot die forging with nitrided and thermally stabilized DLC coated tools

Hot forging dies are subjected to high loads, which can lead to early tool failures. Abrasive wear, plastic deformation and thermal softening of the surface layer can be counteracted in particular by a high surface hardness. Thermochemical diffusion treatments and coatings are established as wear protection measures. DLC coatings, which feature excellent frictional properties and high hardness, are commonly applied on cold forging tools. However, the low coating adhesion to steel and the thermal stability of the diamond bond limit the current range of application. In this study, DLC coatings are applied in metallic treatment atmospheres with the aim of increasing the diamond bond’s temperature resistance. Furthermore, the influence of weak and intense nitriding to coating adhesion is investigated to reduce coating delamination. A pre-selection of modified DLC coatings for hot forging dies was carried out on the basis of hardness and scratch tests. The most promising tungsten DLC coating was tested in serial forging tests. Based on tool contour comparisons before and after forging, the potential as a wear protection measure for hot forging dies was determined. Tool wear was reduced by up to 29 % after 100 forging cycles with the tungsten DLC coating compared to the nitrided reference

Enhancing Anticoagulation Monitoring and Therapy in Patients Undergoing Microvascular Reconstruction in Maxillofacial Surgery: A Prospective Observational Trial

Background: In reconstructive surgery, loss of a microvascular free flap due to perfusion disorders, especially thrombosis, is a serious complication. In recent years, viscoelastic testing (VET) has become increasingly important in point-of-care (POC) anticoagulation monitoring. This paper describes a protocol for enhanced anticoagulation monitoring during maxillofacial flap surgery. Objective: The aim of the study will be to evaluate, in a controlled setting, the predictive value of POC devices for the type of flap perfusion disorders due to thrombosis or bleeding. VET, Platelet monitoring (PM) and standard laboratory tests (SLT) are comparatively examined. Methods/Design: This study is an investigator-initiated prospective trial in 100 patients undergoing maxillofacial surgery. Patients who undergo reconstructive surgery using microvascular-free flaps will be consecutively enrolled in the study. All patients provide blood samples for VET, PM and SLT at defined time points. The primary outcome is defined as free flap loss during the hospital stay. Statistical analyses will be performed using t-tests, including the Bonferroni adjustment for multiple comparisons. Discussion: This study will help clarify whether VET can improve individualized patient care in reconstruction surgery. A better understanding of coagulation in relation to flap perfusion disorders may allow real-time adaption of antithrombotic strategies and potentially prevent flap complications

Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.EC/H2020/633053/EU/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium/ EUROfusio

Dry forming of aluminum

Aluminum parts are used in a wide range of applications. However, the strong adhesion of aluminum to nu-merous tool materials is challenging for production processes. To ensure an economic production of aluminum sheet parts a high quantity of lubricants is currently needed. The additional process steps and operating re-sources associated with their use considerably reduce the sustainability of production. Ecological advantages achieved by lightweight construction during the use phase of aluminum products lose their value drastically when the entire life cycle is considered. The aim of the research project is therefore the development, qualifi-cation and transfer of a surface technology system solution for the optimization of tools, whereby the use of lubricants is dispensed with and an environmentally friendly production of aluminum parts is achieved. Within the scope of the research project, the basic wear mechanisms during the lubricant-free forming of alu-minum sheets were investigated and strategies for industrial implementation were explored. Starting point of the investigations was a holistic view of the tribological system. In addition to process-driven variables such as contact normal stress and temperature, a significant influence of the semi-finished product in terms of sur-face chemistry and topography was found. The inert and particularly smooth design of the tribological contact plays a decisive role in this respect. On the sheet side, the native aluminum oxide layer ensures a separation of the reactive aluminum matrix and its performance was improved by additional electrolytic treatment. Further-more, the adhesive wear was significantly reduced by providing sheet material with a high proportion of ma-terial close to the surface. On the tool side, amorphous hydrogenated carbon (a-C:H) caotings were deposited to provide an inert surface. In order to additionally create a nanoscopic smooth tool surface economically, different action strategies along the process chain for tool production were investigated. In addition to various approaches for optimizing the coating process, these strategies consist of a roughness-oriented material selec-tion and different polishing processes that are variable in the process sequence. All investigations were based on a sequential qualification method (tribometer, strip drawing, application) in order to narrow down the scope of solutions for application tests. Finally, the mechanical-chemical polishing of a-C:H coated forming tools was qualified for industrial application in deep-drawing tests

Migrant-Local Government Relationships in Sending Communities The Power of Politics in Postwar El Salvador

This article analyzes refugee political transnationalism in El Salvador. It assesses the domestic or homeland component of migration history in this Central American country by focusing on the role of both local governments and specific communities. Moreover, it considers differences between areas that vary in terms of the level and type of political organization during and after the civil war, the levels of international migration, population concentration in settlement areas in the United States, and the types of relationships between local authorities and both collective and individual migrants. Studying and comparing political transnationalism may help explain why transnational initiatives progress in some settings but not others. This study considers some of the factors that should be taken into account in order to understand transnational activities in sending communities. The finding show that partisan politics constitute an element to be studied as part of the conditions that may enhance or limit relationships between migrants and local governments in postwar El Salvador