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In this study, for the first time, the application of plasma electrolytic polishing (PEP) of porous Nitinol structures, mimicking a trabecular bone structure, that were additively manufactured, is reported. The cube-shaped samples were polished in a diagonal position three different times. The effect of PEP was evaluated in terms of the polishing depth, the effect on sample chemical composition and a possible shift of the phase transition temperature using microscopy, the energy dispersive X-ray spectroscopy (EDX), and the differential scanning calorimetry (DSC) techniques, respectively. The obtained results demonstrated that the PEP technique is suitable for polishing porous structures up to a certain depth into the sample inner structure and does not have any influence on the chemical composition and the phase transformation temperatures. However, small changes in the specific enthalpy were observable among the investigated samples. These changes could be attributed to the sample chemical inhomogeneity, measurement error, and/or differences in sample size and shape.

Die unterschiedlichen Studien zum Bau von Musikinstrumenten-Prototypen mittels Additiver Fertigung zeigen deutlich die Vorteile der Designfreiheit. Zur industriellen Implementierung fehlen allerdings noch immer die Ansätze.

Im Rahmen des Modellprogrammes zur besseren Versorgung chronisch Kranker förderte das Bundesgesundheitsministerium (BMG) seit 1992 schwerpunktmäßig den Aufbau von Rheumazentren an 21 Orten der Bundesrepublik. Ziel war neben dem Aufbau formaler Strukturen die Verbesserung der Versorgungsqualität durch Koordination und Kooperation vorhandener Einrichtungen.

We provide an overview of recent articles which describe new thinking regarding HLA-B27-associated reactive arthritis (ReA), including those additional infection-related arthritides triggered by microbes that often are grouped under the term ReA.With the advent and continuation of the pandemic, an increasing number of cases and case series of post-COVID-19 arthritis have been reported and classified as ReA. Further, arthritis after COVID-19 vaccination is a new entity included within the spectrum of ReA. New causative microorganisms identified in case reports include Clostridium difficile, Mycoplasma pneumoniae, Giardia lamblia, Leptospira , and babesiosis. SARS-CoV-2 is emerging as a significant etiologic agent for apparent ReA.It is now clear that comprehensive clinical and laboratory investigations, synovial fluid analyses, and close follow-up of patients all are essential to differentiate ReA from diseases that may present with similar clinical attributes. Further, and importantly, additional research is required to define the wide diversity in causative agents, epidemiology, and rare case presentations of these arthritides. Finally, new classification and diagnostic criteria, and updated treatment recommendations, are essential to the advancement of our understanding of ReA.

Wire arc additive manufacturing (WAAM) is an emerging and promising technology for producing medium-to-large-scale metallic components/structures for different industries, i.e., aerospace, automotive, shipbuilding, etc. It is now a feasible alternative to traditional manufacturing processes due to its shorter lead time, low material waste, and cost-effectiveness. WAAM has been widely used to produce components using different materials, including copper-based alloy wires, in the past decades. This review paper highlights the critical aspects of WAAM process in terms of technology, various challenges faced during WAAM process, different in-process and post-process operations, process monitoring methods, various gases, and different types of materials used in WAAM process. Furthermore, it briefly overviews recent developments in depositing different copper-based alloys via WAAM process.

The technology of additive manufacturing (AM) has transformed the fields of machinery, aerospace, and electronics. Adopting cost-effective, precise, and rapid procedures in AM is one of the major concerns of today’s industry. Stereolithography is a promising AM technique that is thought to meet these requirements. However, the fact that materials printed with stereolithography do not have good mechanical properties limits their application, such as in biomedicine and aerospace. Previous studies have shown the shortcomings of stereolithography printers. This research focuses on enhancing the mechanical characteristics of the polymer resin used in stereolithography (SLA)-like liquid crystal display (LCD) 3D printers by fabricating a new AM composite material with carbon fibers. For this reason, chopped carbon fibers (0.1 mm size) at amounts of 0.25 wt% and 0.5 wt% have been used with Acrylonitrile butadiene styrene (ABS)-like photopolymer transparent resin during the printing process, and three different print layer thicknesses were tested. For the design of the experiment (DoE), Q-DAS software was used to analyze the resulting data. A tensile-testing machine was utilized to determine the ultimate strength using the ASTM D638 standard. The results show an increase in the ultimate strength by adding carbon fiber to some extent, but after a certain percentage of carbon fiber added, the strength drops off.

Der Schriftsteller Bertolt Brecht (1898–1956) ist bekannt durch seine Gedichte, Dramen und das von ihm begrundete „epische bzw. dialektische Theater“. Wegen Herzbeschwerden und neuromuskularer Symptome in seiner Jugend wurde bei ihm retrospektiv ein rheumatisches Fieber postuliert. Ausgehend vom heutigen rheumatologischen Wissensstand lasst sich aus den vorliegenden Dokumenten nicht ableiten, dass Brecht sicher ein rheumatisches Fieber hatte. Allenfalls ist eine ganz ungewohnliche Manifestation eines rheumatischen Fiebers zu vermuten mit atypischer rheumatischer Chorea und sehr atypischem Verlauf einer rheumatischen Karditis. Einige Abweichungen vom klassischen Krankheitsbild – das Fehlen von Fieber und Arthritis, keine typische Symptomatik einer Sydenham-Chorea, die fehlende Diagnose eines Herzvitiums in seiner Jugend – fuhren zu umfangreichen differenzialdiagnostischen Uberlegungen. Eine mogliche psychosomatische Genese durch funktionelle Herzbeschwerden muss selbst dann postuliert werden, wenn eine zeitweise vorangegangene organische Ursache nicht ausgeschlossen werden kann. Nur der Einsatz der heute verfugbaren weiterfuhrenden Diagnostik mit Dopplersonographie des Herzens, Kardio-MRT (Magnetresonanztomographie), Rachenabstrichen auf Streptokokken und Streptokokkenserologie wurde ermoglicht haben, die Herzsymptomatik von Brecht in seiner Jugend zweifelsfrei zu diagnostizieren und von funktionellen Herzbeschwerden abzugrenzen. Sein Tod infolge einer bakteriellen Endokarditis mit Nachweis von Coli-Bakterien infolge eines urologischen Eingriffs mit nachfolgenden Fieberschuben und Pyelonephritis ist durch die Auswertung arztlicher Dokumente belegt und zweifelsfrei nachvollziehbar.

Jet-electrolytic Plasma Polishing (Jet-ePP) is a modified form of Bath-ePP to selectively polish and clean local areas with lower-power. When Jet-ePP is used, it must be taken into account how the changed boundary conditions and the additional electrolyte jet parameters influence the basic process. It can be assumed that the plasma polishing changes into electrolytic polishing due to changed boundary conditions, which is not desirable. The non-existent closed boundary conditions must be compensated by setup adjustments. Changes in the phenomenological model of the removal are necessary. The paper shows how the additional and changed process parameters such as fluid flow, distance between anode and cathode influence the individual process phases. Current-time curves are used to investigate the changes in ignition and polishing phases, which are influencing the machining results. Due to these combined data it is possible to find stable process windows. For special changes of the phenomenological model, the physical changes have to be described. To compare the electric parameters such as the voltage drop over the electrolyte of both processes: Jet-ePP and Bath-ePP, equivalent circuit diagrams are used. These describe which changed conditions also lead to the formation of a plasma layer and produce the same effect as in Bath-ePP. In combination with the geometric proportions and the function of the workpiece, the most suitable scientific and industrial application areas are pointed out, making use of the localized jet in comparison with the well-established Bath-ePP process.

Durch die wachsende Produktvielfalt nimmt das Potenzial der additiven Fertigung im Werkzeugbau stetig zu. Ein neuartiger Ansatz ist die hybrid-additive Herstellung von Werkzeugkomponenten mittels Laserauftragschweißen. Mithilfe numerischer Simulationen können effiziente Verfahrstrategien analysiert und prozessbedingte Eigenspannungen und Verformungen reduziert werden. Im Rahmen dieser Arbeit wird ein Finite-Elemente-Modell für den Laserauftragschweißprozess entwickelt und in der Software „LS-Dyna“ validiert. Due to the rising variety of products, the potential of additive manufacturing in tool making is continuously increasing. A novel approach is the hybrid-additive manufacturing of tool components using laser metal deposition (LMD). Numerical simulations can be used to analyze efficient scanning strategies and reduce process-related residual stresses and deformations. Within the scope of this work, a finite-element-model for the LMD process is developed and validated within the software LS-Dyna.

Electrolytic plasma polishing is a hybrid process in which the electrolytic process is an assisting process for a plasma region, which subsequently cleans and polishes the surface of a workpiece. The basic process takes place in an electrolyte bath, where very different starting conditions can be met. The extreme cases are the ignition in the bath, the ignition during a rapid immersion phase and the ignition in a slow immersion phase. Characteristic of these individual cases are the extreme changes of the tool impedance in connection with the electrolyte. The paper shows how the current-voltage characteristic can be measured, without adjustment problems between the process energy source (PES) and the connection impedance. The individual phases of the ignition phase are explained on the basis of a phenomenological model and the changes in the model (equivalent circuit diagram) of the process are taken into account. From these findings, the conditions can be derived to the PES and energy consumption in the ignition phase can be minimized. The basic objective is also to convert the ignition phase into a stable polishing phase and to have as few re-ignition phases as possible during the polishing period. In particular, the boundary conditions for the Bath-PeP are defined, which allow for a fast polishing of the surface, without deteriorating the mechanical properties of the surface or changing the geometry of the functional surface. In contrast to electrolytic polishing, no edge rounding occurs if a correspondingly short processing time is maintained.

Plasma electrolytic Polishing (PeP) is an innovative surface treatment to produce smooth, high-gloss surfaces. It is a thermo-chemical process but often described as a special case of anodic dissolution. PeP is determined by an interplay between plasma chemical, thermochemical, and electrochemical processes. The mechanism is not yet fully understood and part of ongoing research. The planar plasma discharge renders direct observation of the interface extremely difficult. Specially developed flow cells could overcome current experimental limitations. The study investigates phenomena during process initiation, as vapor layer creation and current and temperature signals, using high-speed and thermal imaging to foster understanding and derive optimization strategies

A novel, environmentally friendly, fast, and flexible polishing process for Nitinol parts is presented in this study. Nitinol samples with both superelastic and shape memory properties at room temperature were investigated. The chemical contamination and surface roughness of superelastic Nitinol plates were examined before and after plasma electrolytic polishing. The shift in phase transformation temperature and tensile strength before and after the polishing process were analysed using Nitinol wire with shape memory properties. The obtained experimental results were compared to the data obtained on reference samples examined in the as-received condition. It was found that plasma electrolytic polishing, when the right process parameters are applied, is capable of delivering Nitinol parts with extremely high surface quality. Moreover, it was experimentally proven that plasma electrolytic polishing does not have a negative impact on functionality or mechanical properties of polished parts.

Additive manufacturing of Nitinol is a promising field, as it can circumvent the challenges associated with its conventional production processes and unlock unique advantages. However, the accompanying surface features such as powder adhesions, spatters, ballings, or oxide discolorations are undesirable in engineering applications and therefore must be removed. Plasma electrolytic polishing (PeP) might prove to be a suitable finishing process for this purpose, but the effects of post-processing on the mechanical and functional material properties of additively manufactured Nitinol are still largely unresearched. This study seeks to address this issue. The changes on and in the part caused by PeP with processing times between 2 and 20 min are investigated using Nitinol compression springs manufactured by Laser Beam Melting. As a benchmark for the scanning electron microscope images, the differential scanning calorimetry (DSC) measurements, and the mechanical load test cycles, conventionally fabricated Nitinol springs of identical geometry with a medical grade polished surface are used. After 5 min of PeP, a glossy surface free of powder adhesion is achieved, which is increasingly levelled by further polishing. The shape memory properties of the material are retained without a shift in the transformation temperatures being detectable. The decreasing spring rate is primarily attributable to a reduction in the effective wire diameter. Consequently, PeP has proven to be an applicable and effective post-processing method for additively manufactured Nitinol.

Purpose of Review This article presents a comprehensive narrative review of reactive arthritis (ReA) with focus on articles published between 2018 and 2020. We discuss the entire spectrum of microbial agents known to be the main causative agents of ReA, those reported to be rare infective agents, and those reported to be new candidates causing the disease. The discussion is set within the context of changing disease terminology, definition, and classification over time. Further, we include reports that present at least a hint of effective antimicrobial therapy for ReA as documented in case reports or in double-blind controlled studies. Additional information is included on microbial products detected in the joint, as well as on the positivity of HLA-B27. Recent Findings Recent reports of ReA cover several rare causative microorganism such as Neisseria meningitides, Clostridium difficile, Escherichia coli, Hafnia alvei, Blastocytosis, Giardia lamblia, Cryptosporidium, Cyclospora cayetanensis, Entamoeba histolytica/dispar, Strongyloides stercoralis, β-haemolytic Streptococci, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Mycobacterium bovis bacillus Calmette-Guerin, and Rickettsia rickettsii. The most prominent new infectious agents implicated as causative in ReA are Staphylococcus lugdunensis, placenta- and umbilical cord–derived Wharton’s jelly, Rothia mucilaginosa, and most importantly the SARS-CoV-2 virus. Summary In view of the increasingly large spectrum of causative agents, diagnostic consideration for the disease must include the entire panel of post-infectious arthritides termed ReA. Diagnostic procedures cannot be restricted to the well-known HLA-B27-associated group of ReA, but must also cover the large number of rare forms of arthritis following infections and vaccinations, as well as those elicited by the newly identified members of the ReA group summarized herein. Inclusion of these newly identified etiologic agents must necessitate increased research into the pathogenic mechanisms variously involved, which will engender important insights for treatment and management of ReA. Supplementary Information The online version contains supplementary material available at 10.1007/s11926-021-01018-6.

The coping with rheumatoid arthritis of the famous French impressionist painter Pierre-Auguste Renoir (1841-1919) is described in former publications. The heavily handicapped painter has in his last years created sculptures in cooperation with the sculptor Richard Guino (1890-1973). The extraordinary genesis of the sculptures through a masterful artistic cooperation, as well as the resulting legal issues and shameful copyright infringements, is reported. Renoir's decision to create sculptures with the help of Guido can be attributed to his remarkable artistic vision, vitality, optimistic nature, and strong will and is also a further testimonial of creative coping of an artist overcoming the physical handicap due to rheumatoid arthritis of his final years, so far not described in detail in the medical literature.

An increase in geriatric population coupled by a growing incidence of different vascular ailments including peripheral vascular and coronary artery diseases imply that the medical devices market will continue to enlarge. As demand for minimally invasive surgical procedures and treatments increase, so does the significance of the abilities of nitinol, including shape memory, superelasticity, high fatigue resistance, corrosion resistance and biocompatibility which have revolutionized the medical device manufacturing sector. In order to fully exploit the capabilities of nitinol, sound and application oriented machining processes have to be selected for optimum efficiency. This is especially so for nitinol since it is a hard material to machine owing to its phase transformation and work hardening. Though stand alone research on processing nitinol is available, vital comparison information regarding to strengths and limitations of different machining processes applied in micromachining nitinol is lacking. This study presents on steps in a nitinol processing chain and offers a juxtaposition between different nitinol manufacturing, forming, machining and post processing methods including pointing out how they may affect final part performance. Different performance measurement parameters have been used to categorize the processes and a suitability analysis has been made which can offer a guide on when to use which method.

Zusammenfassung Hintergrund Mit Einführung der Biologika hat sich die Therapie der rheumatoiden Arthritis (RA) hinsichtlich der Wirksamkeit und Kosten grundlegend gewandelt. Ziel dieser Studie ist es, die der S1-Leitlinie der DGRh entsprechende Versorgung von RA-Patienten mit krankheitsmodifizierenden Medikamenten (disease-modifying anti-rheumatic drugs; DMARDs) anhand von Routinedaten der gesetzlichen Krankenversicherung zu analysieren. Methodik Die Abrechnungsdaten der Techniker Krankenkasse wurden retrospektiv für die Jahre 2011 – 2014 analysiert. Im Rahmen von Subgruppenanalysen wurden Verschreibungs- und Versorgungsunterschiede einzelner in der Leitlinie empfohlener Wirkstoffe wie konventionelle DMARDs und Biologika analysiert. Ergebnisse Die Studienpopulation umfasste 55 538 RA-Patienten (29,7 % inzidente, 70,3 % prävalente; 22,3 % M05: Seropositive chronische Polyarthritis, 77,7 % M06: Sonstige chronische Polyarthritis). Lediglich 21 616 Versicherte (38,9 %) bekamen mindestens einmal innerhalb eines Jahres nach der Erstdiagnose ein in der Leitlinie empfohlenes konventionelles DMARD oder Biologikum verordnet. Bei den inzidenten Patienten lag die Versorgungsquote mit krankheitsmodifizierenden Medikamenten unterhalb der prävalenten Patienten (31,5 vs. 42,1 %). 60,9 % der M05-Patienten und nur 29,7 % der M06-Patienten erhielten einen Einzelwirkstoff nach Index-Diagnose. Wenn ein Basistherapeutikum verordnet wurde, dann wurde dies durchschnittlich innerhalb eines Quartals nach Erstdiagnose verschrieben. Die führende Rolle in der Verschreibung von Basistherapeutika für die Indexmedikation übernimmt der Rheumatologe. Dennoch zeigte sich, dass nur 68,3 % der Patienten mindestens einmal innerhalb eines Jahres nach der Erstdiagnose einen rheumatologisch tätigen Facharzt konsultierten. Schlussfolgerung Mittels einer großen Stichprobe konnten Unterschiede in der leitliniengerechten Verordnung von krankheitsmodifizierenden Arzneimitteln für verschiedene Subgruppen sowie eine Unterversorgung bei nicht vom internistischen Rheumatologen behandelten Patienten aufgezeigt werden.

This work focuses on the production of high conductive Aluminum based MMC or co-cast components obtained by casting processes. The activity started from the “reinforcement” materials to be used for the MMC fabrication. Carbon based materials were chosen and their characterization under the thermal point of view was carried out. Several arrangements for matrix-reinforcement and matrix-insert couples were evaluated and their potential performances were estimated via numerical simulation. Aluminum-Diamond, Aluminum-Reduced Graphene Oxide and Aluminum-Thermal Pyrolytic Graphite components were produced and their performances were experimentally evaluated. Finally, demonstrator utilizing the novel materials were produced and tested in their relevant working condition.

The recent paper from Sepriano et al provides an extremely important new insight on the concept of axial spondyloarthritis (axSpA).1 Clearly, the Gestalt of axSpA is heterogeneous, with three recognisable clinical entities labelled as: ‘pure axial SpA’, ‘axial SpA with peripheral signs’ and ‘axial SpA at risk’. The finding given in the paper suggests a larger overlap between axSpA and pSpA than anticipated at the time when the Assessment of SpondyloArthritis international Society (ASAS) criteria were developed. Thus, the question arises as to how accurately the three recognisable clinical entities of the ASAS classification criteria represent the diseases entities originally lumped together in the historical concept of SpA. The unifying historical concept of SpA lumps together an inter-related yet heterogeneous group of disorders which includes ankylosing spondylitis …

The paper presents ways of utilising the additive manufacturing process 3D-printing using renewable biobased materials, with a focus on adapted packaging for sensitive components. This application provides an attractive scenario for sustainable production and the re- or upcycling of waste material such as wood flour, rice husk or miscanthus fibre. Packaging of prototypes with sensitive or filigree structures or made of fragile materials is currently difficult, because standardized packages are often not suitable and cost for adapted packages are high. Within this study, CAD-data based adapted packaging made of renewable raw materials is addressed. The 3D-printing process was modified for using conditioned biobased fibre and a special binder. Furthermore, a software tool was developed to create adapted packaging designs by using the individual part geometry. In this way and in combination with AM processes, sustainable and biodegradable packaging for complex components can be generated within a short time. The manufactured packaging is conform to the demands of packaging for fragile goods and can be produced just-in-time.

Recent studies regarding the frequency of Chlamydia-induced reactive arthritis (ReA) are reviewed, with a focus on the question of whether the entity is in fact disappearing or whether it is simply being underdiagnosed/underreported. Epidemiological reports indicate diversity in the frequency of Chlamydia-associated ReA in various parts of the world, with evidence of declining incidence in some regions. The hypothesis that early effective treatment with antibiotics prevents the manifestation of Chlamydia-associated ReA requires further investigation. For clinicians, it is important to remember that ReA secondary to Lymphogranuloma venereum (LGV) serovars L1–L3 of C. trachomatis is probably underestimated due to a limited awareness of this condition, the re-emergence in Western countries of LGV overall, and the present increasingly rare classical inguinal presentation.

With the market entry of biologics, the treatment of rheumatoid arthritis (RA) has changed fundamentally in terms of efficacy and costs.of this study is to analyse the treatment according the guideline of the German society of rheumatology for RA patients with disease-modifying anti-rheumatic drugs (DMARDs) using claims data from the statutory health insurance.The claims data of the Techniker Krankenkasse were analysed retrospectively for the years 2011 - 2014. Subgroup analyses were used to conduct prescription and treatment differences with respect to guideline-recommended conventional DMARDs and biologics.The study population included 55,538 RA patients (29.7 % incidence, 70.3 % prevalence, 22.3 % M05: Seropositive rheumatoid arthritis, 77.7 % M06: Other rheumatoid arthritis). Only 21,616 insured patients (38.9 %) were prescribed a guideline-recommended conventional DMARD or biologic at least once within one year of/after the first diagnosis. Among incident patients, the coverage rate with disease-modifying drugs was below the prevalence patients (31.5 % vs. 42.1 %). 60.9 % of M05 patients and only 29.7 % of M06 patients received a single DMARD after index diagnosis. If a DMARD has been prescribed, then it was prescribed, on average, within the first quarter of the initial diagnosis. The leading role in the prescription of basic therapies for index medication is provided by the rheumatologist. Nevertheless, 68.3 % of patients consulted a specialist in rheumatology at least once within a year of the first diagnosis.The results of this large sample show differences in the guideline recommended prescription of disease-modifying drugs for different subgroups of RA as well as an undersupply in patients not treated by the rheumatologist.Mit Einführung der Biologika hat sich die Therapie der rheumatoiden Arthritis (RA) hinsichtlich der Wirksamkeit und Kosten grundlegend gewandelt. Ziel dieser Studie ist es, die der S1-Leitlinie der DGRh entsprechende Versorgung von RA-Patienten mit krankheitsmodifizierenden Medikamenten (disease-modifying anti-rheumatic drugs; DMARDs) anhand von Routinedaten der gesetzlichen Krankenversicherung zu analysieren.Die Abrechnungsdaten der Techniker Krankenkasse wurden retrospektiv für die Jahre 2011 – 2014 analysiert. Im Rahmen von Subgruppenanalysen wurden Verschreibungs- und Versorgungsunterschiede einzelner in der Leitlinie empfohlener Wirkstoffe wie konventionelle DMARDs und Biologika analysiert.Die Studienpopulation umfasste 55 538 RA-Patienten (29,7 % inzidente, 70,3 % prävalente; 22,3 % M05: Seropositive chronische Polyarthritis, 77,7 % M06: Sonstige chronische Polyarthritis). Lediglich 21 616 Versicherte (38,9 %) bekamen mindestens einmal innerhalb eines Jahres nach der Erstdiagnose ein in der Leitlinie empfohlenes konventionelles DMARD oder Biologikum verordnet. Bei den inzidenten Patienten lag die Versorgungsquote mit krankheitsmodifizierenden Medikamenten unterhalb der prävalenten Patienten (31,5 vs. 42,1 %). 60,9 % der M05-Patienten und nur 29,7 % der M06-Patienten erhielten einen Einzelwirkstoff nach Index-Diagnose. Wenn ein Basistherapeutikum verordnet wurde, dann wurde dies durchschnittlich innerhalb eines Quartals nach Erstdiagnose verschrieben. Die führende Rolle in der Verschreibung von Basistherapeutika für die Indexmedikation übernimmt der Rheumatologe. Dennoch zeigte sich, dass nur 68,3 % der Patienten mindestens einmal innerhalb eines Jahres nach der Erstdiagnose einen rheumatologisch tätigen Facharzt konsultierten.Mittels einer großen Stichprobe konnten Unterschiede in der leitliniengerechten Verordnung von krankheitsmodifizierenden Arzneimitteln für verschiedene Subgruppen sowie eine Unterversorgung bei nicht vom internistischen Rheumatologen behandelten Patienten aufgezeigt werden.

Plasma electrolytic polishing (PeP) is a non-mechanical surface treatment by the means of cold plasma and electrolyte for polishing of electric conductive materials and surfaces. The paper examines how smoothed surface structures change their corrosion resistance after PeP treatment. For selected materials, the untreated and the treated surfaces are compared, in particular by means of the salt water spray experiment. The results are primarily used to optimize the PeP process parameters. Secondarily, it was examined which minimum requirements must be fulfilled by the PeP treatment with regard to the surface structure. The manipulation of the surface structure through the innovative PeP process varies the thermo-electrical characteristics beside the corrosion resistance of the electric conductive material.

Die mexikanische Malerin Frida Kahlo, geboren 1907 als Tochter eines deutsch mexikanischen Ehepaars – die Mutter Mexikanerin, der deutsche Vater eingebürgert-, ist eine der berühmtesten weiblichen Malerinnen der ersten Hälfte des 20. Jahrhunderts. Dazu trug nicht allein ihre außergewöhnliche Kunst bei, sondern auch ihre turbulente Lebensgeschichte mit dem Künstler Diego Rivera und die von Schmerz geprägte Krankengeschichte. Berühmt wurde sie jedoch erst nach ihrem Tod als eine Symbolfigur weiblicher Kreativität und eines von Leiden, Lieben und Unabhängigkeitsstreben geprägten Lebens.

This work focuses on the production of new high conductive carbon based MMC (Metal Matrix Composites) or co-cast components obtained by casting processes. These novel thermally conductive structures are designed to face modern heat management challenges in critical fields such as power micro-electronics, automotive and aerospace industries, renewable energy generation as well as highest performance combustion engines. The sought parts will be assembled by different heat conductive aluminum-carbon composites and for this reason different heat conductive MMCs have been studied. Their combination into once cast aluminum part may allow the part to meet applicative needs for heat management challenges. The cast production routes as well as thermal behavior of the obtained materials has been studied by means of numerical (Finite Element Methods) approaches in order to determine the effective thermal conductivity in the different directions of heat dissipation. Some kinds of casting methods have been FEM simulated and then performed practically. TPG/aluminum interface microstructure has been studied.

Plasma electrolytic processes have gained attention from metal finishing industries due to their capability to considerably enhance surface properties. Especially, plasma electrolytic polishing is an innovative surface treatment resulting in very smooth, high-gloss surfaces with improved corrosion resistance. Although it has many advantages compared to electro polishing, just a few articles have been published in the field of plasma electrolytic polishing until now (mainly of stainless steel, titanium); the machining of other materials remains challenging. In this contribution, the authors provide an overview of plasma electrolytic polishing and describe new work in the field of polishing copper and its alloys. Transferring plasma electrolytic polishing to other metals and material geometries requires an adaption of the experimental conditions. To overcome this challenge a systematic methodology was developed. Several parameters, like electrolyte composition and complexing agents are investigated. Surface roughness as well as gloss was determined as function of processing time and voltage and compared to conventional electro polishing.

Micro-EDM is a well-known process for precision micro machining of difficult to cut materials. It is especially beneficial for machining of complex micro structures such as deep bores, grooves or undercuts in highly wear resistant materials. In the last years, research has successfully applied the assisting electrode method as a suitable process for machining non-conducting ceramics by micro-EDM. There, the EDM process is initiated after applying an electrically conductive starting layer onto the surface of the ceramic. Due to the great variety of ceramics like oxide ceramics, non-oxide ceramics or ceramic composites, different mechanisms for material removal can be observed depending on the raw material and its composition. Particularly for production oriented reasons it is necessary to determine the specific ablation behaviour of each ceramic with regard to the used process parameters. In this study two different ceramic composites, ATZ (Alumina Toughened Zirconia, ZrO2-Al2O3) and Si3N4-TiN (Titanium Nitride toughened Silicon Nitride), were investigated considering their ablation behaviour. Experiments were carried out to determine the maximum achievable aspect ratios of micro bores, the resulting surface quality and the possibility for machining complex 3D-structures by EDM-milling.

Efficient lightweight structures require intelligent materials that meet versatile functions. Especially, carbon-fiber-reinforced polymers (CFRPs) are gaining relevance. Their increasing use aims at reducing energy consumption in many applications. CFRPs are generally very light in weight, while at the same time being extremely stiff and strong (specific strength: CFRPs: 1.3 Nm kg–1, steel: 0.27 Nm kg–1; specific stiffness: CFRPs: 100 Nm kg–1, steel: 25 Nm kg–1). To increase performance and especially functionality of CFRPs, the integration of microelectronic components into CFRP parts is aspired. The functionalization by sensors, actuators and electronics can enable a high lightweight factor and a new level of failure-safety. The integration of microelectronic components for this purpose requires a working procedure to provide electrical contacts for a reliable connection to energy supply and data interfaces. To overcome this challenge, metalized carbon fibers are used. Metalized fibers are, similar to the usual reinforcing fibers, able to be soldered and therefore easy to incorporate into CFRPs. Unfortunately, metalized fibers have to be pre-treated by flux-agents. Until now, there is no flux which is suitable for mass production without destroying the polymer of the CFRP. The process of plasma electrolytic polishing (PeP) could be an option, but is so far not available for copper. Thus, in this study, plasma electrolytic polishing is transferred to copper and its alloys. To achieve this, electrolytic parameters as well as the electrical setup are adapted. It can be observed that the gloss and roughness can be adjusted by means of this procedure. Finally, plasma electrolytic polishing is used to treat thin copper layers on carbon fibers.

Biomanufactured parts, for implant or generally in-vivo use, have high requirements for surface properties. Depending on their field of application, not only smooth, but also well-defined surfaces, i.e. roughness parameters, must be set to allow for the respective functionalities such as optimal cell growth or minimal friction and wear. While for many parts mechanical polishing procedures are state-of-the-art, which are time-consuming and limited in their flexibility, established electrolytic polishing processes often incorporate aggressive media such as acids. Plasma electrolytic Polishing (PeP), a high-voltage process combining anode dissolution and plasma-chemical processes, can be considered a suitable alternative. The paper focusses on current investigations of PeP and shows application scenarios, also pointing out necessary development directions to introduce PeP to industrial biomanufacturing process chains.

Objective: High dose intravenous glucocorticoid (IVGC) pulse therapy is known to effectively reduce inflammatory signs and symptoms in patients with active inflammatory conditions. However, the efficacy of IVGC in ankylosing spondylitis (AS) is not clearly established. Methods: We performed a retrospective analysis with repeated measurements including patients with active, NSAID refractory axial AS (n=15) who underwent high dose IVGC pulse therapy. Parameters of clinical and humoral disease activity were compared to active AS patients (n=14) under continuous anti-TNF treatment. Patients were seen every 3 months and followed up for a total period of 12 months. Results: Both IVGC pulse and anti-TNF therapy lead to a significant and sustained reduction of the mean bath ankylosing spondylitis disease activity index (BASDAI 7.4 ± 1.5 at baseline vs. 5.4 ± 2.1 at 12 months in the pulse group and 6.9 ± 1.2 at baseline vs. 5.0 ± 2.7 at 12 months in the anti-TNF group, p

Today ceramics are used in many industrial applications, for example, in the biomedical field, for high-temperature components or for cutting tools. This is attributed to their excellent mechanical and physical properties, as low density, high strength, and hardness or chemical resistance. However, these specific mechanical properties lead to problems regarding the postprocessing of ceramics. In particular, cutting processes require expensive tools which cause high manufacturing costs to machine ceramics. Consequently, there is a demand for alternative machining processes. Microelectrical discharge machining (micro-EDM) is a thermal abrasion process which is based on electrical discharges between a tool and a workpiece. The advantages of micro-EDM are more and more in focus for ceramic machining. These advantages include the process of being a noncontact technology, an independency of material brittleness and hardness, a low impact on the material, and the achievable microstructures. This paper presents the current state of investigations regarding micro-EDM of ceramics. Beside the process principle of EDM, the used procedures for machining ceramics and insulating ceramics are described. Furthermore several machining examples are presented to demonstrate the possibilities of the micro-EDM process with regard to the machining of ceramics.

Micro EDM (Electrical Discharge Machining) is a known nonconventional process for the machining of hard to cut materials. Due to its ablating nature based on melting and evaporation through heat induced by electrical discharges, it can function independently of the hardness, toughness or brittleness of the workpiece. Thus micro EDM is a possible process to fulfill the requirements of higher precision and high quality in carbide metal machining. Thereby the surface and the roughness of machined carbide metals depend on the discharge energy used. For machining carbide metals with high surface quality pulse generators with ultra-short discharges are required. This paper presents the development of a two-staged pulse generator with the ability to provide ultra-short pulses by using a two-staged pulse. The current and voltage signals of the discharges were recorded and their characteristics were analyzed.

Kurzfassung Bei der Endbearbeitung von rotationssymmetrischen gehärteten Präzisionskomponenten wird das Außenrundschleifen zunehmend durch das Hartdrehen ersetzt. Dies ist jedoch mit einer Drallbildung auf der Werkstückoberfläche verbunden. Bei der Nutzung eines gedrehten Wellenabsatzes als Dichtungsgegenlauffläche besitzt die Drallstruktur eine Förderwirkung auf den Schmierstoff und kann somit eine permanente Leckage einer solchen Dichtstelle verursachen. Aus diesem Grund wurde ein neues Verfahren zur Erzeugung einer drallfreien Oberfläche entwickelt, welches als „Start-Stopp-Drehen“ bezeichnet wird. Auf der Basis experimenteller Untersuchungen konnte nachgewiesen werden, dass die Erzeugung förderneutraler Oberflächen mit diesem Verfahren möglich ist.

In metal forming, lubricants have to be used to prevent corrosion or to reduce friction and tool wear. From an economical and ecological point of view, the aim is to avoid the usage of lubricants. For dry deep drawing of aluminum sheets it is intended to apply locally micro-structured wear-resistant carbon based coatings onto steel tools. One type of these coatings are diamond layers prepared by chemical vapor deposition (CVD). Due to the high strength of diamond, milling processes are unsuitable for micro-structuring of these layers. In contrast to this, micro electrical discharge machining (micro EDM) is a suitable process for micro-structuring CVD-diamond layers. Due to its non-contact nature and its process principle of ablating material by melting and evaporating, it is independent of the hardness, brittleness or toughness of the workpiece material. In this study the deposition and micro electrical discharge machining of silicon incorporated CVD-diamond (Si-CVD-diamond) layers were presented. For thi...