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Counterfeiting is a significant problem for safety-critical systems, since cyber-information, such as a quality control certification, may be passed off with a flawed counterfeit part. Safety-critical systems, such as planes, are at risk because cyber-information cannot be provably tied to a specific physical part instance (e.g., impeller). This paper presents promising initial work showing that using piezoelectric sensors to measure impedance identities of parts may serve as a physically unclonable function that can produce unclonable part instance identities. When one of these impedance identities is combined with cyber-information and signed using existing public key infrastructure approaches, it creates a provable binding of cyber-information to a specific part instance. Our initial results from experimentation with traditionally and additively manufactured parts indicate that it will be extremely expensive and improbable for an attacker to counterfeit a part that replicates the impedance signature of a legitimate part.

Cyber-physical security is a major concern in the modern environment of digital manufacturing, wherein a cyber-attack has the potential to result in the production of defective parts, theft of IP, or damage to infrastructure or the operator have become a real threat that have the potential to create bad parts. Current cyber only solutions are insufficient due to the nature of manufacturing environments where it may not be feasible or even possible to upgrade physical equipment to the most current cyber security standards, necessitating an approach that addresses both the cyber and the physical components. This paper proposes a new method for detecting malicious cyber-physical attacks on additive manufacturing (AM) systems. The method makes use of a physical hash, which links digital data to the manufactured part via a disconnected side-channel measurement system. The disconnection ensures that if the network and/or AM system becomes compromised, the manufacturer can still rely on the measurement system for attack detection. The physical hash ensures protection of the intellectual property (IP) associated with both process and toolpath parameters while also enabling in situ quality assurance. In this paper, the physical hash takes the form of a QR code that contains a hash string of the nominal process parameters and toolpath. It is manufactured alongside the original geometry for the measurement system to scan and compare to the readings from its sensor suite. By taking measurements in situ, the measurement system can detect in real-time if the part being manufactured matches the designer’s specification. In this paper, the overall concept and underlying algorithm of the physical hash is presented. A proof-of-concept validation is realized on a material extrusion AM machine, to demonstrate the ability of a physical hash and in situ monitoring to detect the existence (and absence) of malicious attacks on the STL file, the printing process parameters, and the printing toolpath.

In this paper, the authors explore the use of impedance-based monitoring techniques for in-situ detection of additive manufacturing build defects. By physically coupling a piezoceramic (PZT) sensor to the part being fabricated, the measured electrical impedance of the PZT can be directly linked to the mechanical impedance of the part. It is hypothesized that one can detect build defects in geometry or material properties in-situ by comparing the signatures collected during printing of parts with that of a defect-free control sample. In this paper, the authors explore the layer-to-layer sensitivity for both PZT sensors embedded into printed parts and for a fixture-based PZT sensor. For this work, this concept is evaluated in context of material jetting. A set of control samples is created and used to establish a baseline signature. (e.g., internal voids) are fabricated and their layer-to-layer signatures are compared to a control sample. Using this technique, the authors demonstrate an ability to track print progress and detect defects as they occur. For embedded sensors the defects were detectable at 2.28% of the part volume (95.6 mm3) and by fixture-based sensors when it affected 1.38% of the part volume.

Es existieren keine aktuellen Daten, die die Weiterbildungssituation an deutschen neurologischen Kliniken darstellen. Um die hohe Qualitat der neurologischen Patientenversorgung langfristig sichern zu konnen, ist es von essenzieller Wichtigkeit, die Arbeits- und Weiterbildungsbedingungen an neurologischen Kliniken zu evaluieren. Die deutschlandweite Studie hat zum Ziel, Chancen sowie Hemmnisse der neurologischen Weiterbildung zu erkennen und Anregungen zu Veranderungen der Weiterbildungskurrikula zu geben. Die onlinebasierte Befragung erfolgte von Februar bis Mai 2017. Es nahmen 953 in Weiterbildung zum Facharzt fur Neurologie befindliche Arzte teil. Uber die Halfte der Befragten gab an, mit der Weiterbildung an ihrer Klinik zufrieden zu sein. Als eines der Kernprobleme, die die klinische Weiterbildung erschweren, wird die Arbeitsverdichtung angesehen. Daneben fuhren organisatorische Hindernisse innerhalb der Klinik, wie eine schlechte Struktur der Weiterbildung oder unklare Ansprechpartner zu Unzufriedenheit der Befragten. Die Grose oder Art der Klinik sowie das vorherrschende Dienstsystem haben nur einen geringen Einfluss auf die Qualitat der Weiterbildung, obgleich sich Unterschiede insbesondere bei der Selbsteinschatzung der Teilnehmer im Zusammenhang mit der Arbeitsstelle (Universitat/Lehrkrankenhaus vs. nichtuniversitare Klinik) zeigten. Die neurologische Weiterbildung kann bereits durch einfache Masnahmen, wie der Einfuhrung eines verbindlichen Rotationssystems, eines innerklinischen Mentorings und einer kontinuierlichen „Feedback-Kultur“, verbessert werden. Daneben ist es zusatzlich notwendig, das arztliche Personal konsequent von administrativen Aufgaben zu entlasten, um Zeit fur die neurologische Weiterbildung und das Erlernen von Kompetenzen zu schaffen.

One of the key advantages of additive manufacturing (AM) is its digital thread, which allows for rapid communication, iteration, and sharing of a design model and its corresponding physical representation. While this enables a more efficient design process, it also presents opportunities for cyber-attacks to impact the physical word. In this paper the authors examine potential attack vectors along the Additive Manufacturing process chain. Specifically, the effects of cyber-physical attacks, and potential means for detecting them, are explored. To explore the potential implications of such an attack, a case study was conducted to evaluate the ability of human subjects to detect and diagnose a cyber-physical attack on the STL file of a test specimen. Based on the results of this study, recommendations are presented for preventing and detecting cyber-physical attacks on AM processes.

Purpose This work proposes the utilization of electromechanical impedance measurements as a means of non-destructive evaluation (NDE) for additive manufacturing (AM). The effectiveness and sensitivity of the technique for a variety of defect types commonly encountered in AM are investigated. Design/methodology/approach To evaluate the feasibility of impedance-based NDE for AM, the authors first designed and fabricated a suite of test specimens with build errors typical of AM processes, including dimensional inaccuracies, positional inaccuracies and internal porosity. Two polymer AM processes were investigated in this work: material jetting and extrusion. An impedance-based analysis was then conducted on all parts and utilized, in a supervised learning context, for identifying defective parts. Findings The newly proposed impedance-based NDE technique has been proven to be an effective solution for detecting several types of print defects. Specifically, it was shown that the technique is capable of detecting print defects resulting in mass change (as small as 1 per cent) and in feature displacement (as small as 1 mm) in both extruded nylon parts and jetted VeroWhitePlus parts. Internal porosity defects were also found to be detectable; however, the impact of this defect type on the measured impedance was not as profound as that of dimensional and positional inaccuracies. Originality/value Compared to currently available NDE techniques, the newly proposed impedance-based NDE is a functional-based technique with the advantages of being cost-effective, sensitive and suitable for inspecting AM parts of complex geometry and deeply embedded flaws. This technique has the potential to bridge the existing gaps in current NDE practices, hence paving the road for a wider adoption of AM to produce mission-critical parts.

Industries such as orthodontics and athletic apparel are adopting vat photopolymerization (VP) to manufacture customized products with performance tailored through geometry. However, vat photopolymerization is limited by low manufacturing speeds and the trade-off between manufacturable part size and feature resolution. Current VP platforms and their optical sub-systems allow for simultaneous maximization of only two of three critical manufacturing metrics: layer fabrication time, fabrication area, and printed feature resolution. The Scanning Mask Projection Vat Photopolymerization (S-MPVP 1 ) system was developed to address this shortcoming. However, models developed to determine S-MPVP process parameters are accurate only for systems with an intensity distribution that can be approximated with a first order Gaussian distribution. Limitations of optical elements and the use of heterogeneous photopolymers result in non-analytic intensity distributions. Modeling the effect of non-analytic intensity distribution on the resultant cure profile is necessary for accurate manufacturing of multiscale products. In this work, a model to predict the shape of cured features using analytic and non-analytic intensity distribution is presented. First, existing modeling techniques developed for laser and mask projection VP processes were leveraged to create a numerical model to relate the process parameters (i.e. scan speed, mask pattern irradiance) of the S-MPVP system with the resulting cure profile. Then, by extracting the actual intensity distribution from the resin surface, we demonstrate the model's ability to use non-analytic intensity distribution for computing the irradiance for any projected pattern. Using a custom S-MPVP system, process parameters required to fabricate test specimens were experimentally determined. These parameters were then input into the S-MPVP model and the resulting cure profiles were simulated. Comparison between the simulated and printed specimens dimensions demonstrates the model’s effectiveness in predicting the dimensions of the cured shape with an error of 2.9%.

Es werden die unterschiedlichen Pathomechanismen ausgewahlter peripherer Nervenerkrankungen diskutiert und die vielfaltigen Ursachen dargestellt. Neben der haufig auftretenden, diabetischen Polyneuropathie werden die akut und chronisch inflammatorischen Neuropathien besprochen. Es werden die verschiedenen Schadigungsmuster auf makroskopischer als auch histologischer Ebene dargestellt und beteiligte Stoffwechselwege, zellulare Schadigungsmechanismen und immunologische Hintergrunde beleuchtet. Insbesondere die ursachlichen Ausloser sowie die Autoimmunmechanismen des Guillain-Barre-Syndroms (GBS) als auch der chronischen inflammatorisch-demyelinisierenden Polyneuropathie werden betrachtet und Therapiemoglichkeiten kritisch diskutiert. Das Prinzip des molekularen Mimikry wird vermittelt.

Three-dimensional lattices have applications across a range of fields including structural lightweighting, impact absorption and biomedicine. In this work, lattices based on triply periodic minimal surfaces were produced by polymer additive manufacturing and examined with a combination of experimental and computational methods. This investigation elucidates their deformation mechanisms and provides numerical parameters crucial in establishing relationships between their geometries and mechanical performance. Three types of lattice were examined, with one, known as the primitive lattice, being found to have a relative elastic modulus over twice as large as those of the other two. The deformation process of the primitive lattice was also considerably different from those of the other two, exhibiting strut stretching and buckling, while the gyroid and diamond lattices deformed in a bending dominated manner. Finite element predictions of the stress distributions in the lattices under compressive loading agreed with experimental observations. These results can be used to create better informed lattice designs for a range of mechanical and biomedical applications. (C) 2017 The Authors. Published by Elsevier Ltd. Engineering and Physical Sciences Research Council [EP/I033335/2]; Innovate UK [102665]; National Science Foundation [1261162] This work was supported by the Engineering and Physical Sciences Research Council [grant number EP/I033335/2], Innovate UK [project number 102665], and the National Science Foundation [award no. 1261162]. Thanks to Mark East, Mark Hardy, Joe White, Jason Greaves and Tom Buss.

Currently, no data are available, which reflect the situation of medical doctors specializing in neurology in German hospitals. In order to secure the high standard of neurological patient care it is essential to evaluate the working conditions and the specialty training in neurology.This nationwide survey was conducted throughout Germany with the aim to address problems and to give suggestions for improvements in neurological training curricula.The survey was online from February to May 2017 and 953 neurologists undergoing further training participated.More than half of the young neurologists were satisfied with their medical training. One of the main problems that complicates clinical training is the workload. In addition, organizational obstacles within the clinic, such as poor structure of education or a lack of mentors, lead to dissatisfaction among participants. The size or type of the department, as well as the prevailing service system, exert only a minor influence on the quality of specialist training, although there were differences especially in the self-assessment of the participants in connection with the type of department (university hospital versus public or private hospital).Specialist training in neurology can be improved by simple arrangements, e. g., the introduction of a binding rotation scheme, internal mentoring and structured feedback. In addition, it will be necessary to relieve medical staff of administrative duties in order to create time for training and the learning of competencies.

Der Hausarzt ist heute ein breit weitergebildeter Facharzt, der die Patienten umfassend von der Pravention uber die Diagnostik und Therapie bis zur Palliativsituation nach wissenschaftlichen Leitlinien und Behandlungsprogrammen betreut. Die Mitwirkung bei Diagnostik und Therapie und die Beratung des Patienten verlangen von ihm aktuelles evidenzbasiertes Wissen. Hausarzte benotigen Fortbildung sowohl allgemein zu Tumorerkrankungen als Prasenzfortbildung als auch speziell zu den einzelnen Krebserkrankungen als „Vorratsbank“ (Onlinefortbildung). Die Hausarzte streben eine stabile koordinierte Betreuung auch der Tumorkranken in Form der vertraglich vereinbarten „Versorgungslandschaft“ an, dabei handelt es sich um eine Vereinbarung von Hausarzten mit den Spezialisten in Ambulanz und Kliniken sowie Patienten mit den Krankenkassen zur Kooperation, Kommunikation, Qualitatssicherung und Finanzierung auserhalb des Kollektivvertrags.

Allergic rhinoconjunctivitis (AR) is an allergic disorder of the nose and eyes affecting about a fifth of the general population. Symptoms of AR can be controlled with allergen avoidance measures and pharmacotherapy. However, many patients continue to have ongoing symptoms and an impaired quality of life; pharmacotherapy may also induce some side-effects. Allergen immunotherapy (AIT) represents the only currently available treatment that targets the underlying pathophysiology, and it may have a disease-modifying effect. Either the subcutaneous (SCIT) or sublingual (SLIT) routes may be used. This Guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on AIT for AR and is part of the EAACI presidential project “EAACI Guidelines on Allergen Immunotherapy.” It aims to provide evidence-based clinical recommendations and has been informed by a formal systematic review and meta-analysis. Its generation has followed the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included involvement of the full range of stakeholders. In general, broad evidence for the clinical efficacy of AIT for AR exists but a product-specific evaluation of evidence is recommended. In general, SCIT and SLIT are recommended for both seasonal and perennial AR for its short-term benefit. The strongest evidence for long-term benefit is documented for grass AIT (especially for the grass tablets) where long-term benefit is seen. To achieve long-term efficacy, it is recommended that a minimum of 3 years of therapy is used. Many gaps in the evidence base exist, particularly around long-term benefit and use in children. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by widespread oligodendroglial cytoplasmic inclusions of filamentous α-synuclein, and neuronal loss in autonomic centres, basal ganglia and cerebellar circuits. It has been suggested that primary oligodendroglial α-synucleinopathy may represent a trigger in the pathogenesis of MSA, but the mechanisms underlying selective vulnerability and disease progression are unclear. The post-mortem analysis of MSA brains provides a static final picture of the disease neuropathology, but gives no clear indication on the sequence of pathogenic events in MSA. Therefore, alternative methods are needed to address these issues. We investigated selective vulnerability and disease progression in the transgenic PLP-α-syn mouse model of MSA characterized by targeted oligodendroglial α-synuclein overexpression aiming to provide a neuropathological correlate of motor deterioration. We show progressive motor deficits that emerge at 6 months of age and deteriorate up to 18 months of follow-up. The motor phenotype was associated with dopaminergic cell loss in the substantia nigra pars compacta at 6 months, followed by loss of striatal dopaminergic terminals and DARPP32-positive medium sized projection neurons at 12 months. Olivopontocerebellar motor loops remained spared in the PLP-α-syn model of MSA. These findings replicate progressive striatonigral degeneration underlying Parkinson-variant MSA. The initiation of the degenerative process was linked to an increase of soluble oligomeric α-synuclein species between 2 and 6 months. Early region-specific α-synuclein-associated activation profile of microglia was found in MSA substantia nigra. The role of abnormal neuroinflammatory signalling in disease progression was further supported by increased levels of CD68, CCL3, CCL5 and M-CSF with a peak in aged PLP-α-syn mice. In summary, transgenic PLP-α-syn mice show a distinctive oligodendroglial α-synucleinopathy that is associated with progressive striatonigral degeneration linked to abnormal neuroinflammatory response. The model provides a relevant tool for preclinical therapeutic target discovery for human Parkinson-variant MSA.

Food allergy can result in considerable morbidity, impairment of quality of life, and healthcare expenditure. There is therefore interest in novel strategies for its treatment, particularly food allergen immunotherapy (FA-AIT) through the oral (OIT), sublingual (SLIT), or epicutaneous (EPIT) routes. This Guideline, prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Task Force on Allergen Immunotherapy for IgE-mediated Food Allergy, aims to provide evidence-based recommendations for active treatment of IgE-mediated food allergy with FA-AIT. Immunotherapy relies on the delivery of gradually increasing doses of specific allergen to increase the threshold of reaction while on therapy (also known as desensitization) and ultimately to achieve post-discontinuation effectiveness (also known as tolerance or sustained unresponsiveness). Oral FA-AIT has most frequently been assessed: here, the allergen is either immediately swallowed (OIT) or held under the tongue for a period of time (SLIT). Overall, trials have found substantial benefit for patients undergoing either OIT or SLIT with respect to efficacy during treatment, particularly for cow's milk, hen's egg, and peanut allergies. A benefit post-discontinuation is also suggested, but not confirmed. Adverse events during FA-AIT have been frequently reported, but few subjects discontinue FA-AIT as a result of these. Taking into account the current evidence, FA-AIT should only be performed in research centers or in clinical centers with an extensive experience in FA-AIT. Patients and their families should be provided with information about the use of FA-AIT for IgE-mediated food allergy to allow them to make an informed decision about the therapy. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Das Auftreten von Hirntumoren im Kindes- und Jugendalter ist eng mit der Entwicklung des Zentralnervensystems verknupft, wahrend der viele unterschiedliche Zellpopulationen uber einen gewissen Zeitraum anfallig fur tumorauslosende Veranderungen sein konnen. Dies spiegelt sich in der enormen Vielfalt von Tumorarten wider, von denen einige haufiger, andere sehr selten auftreten und die oft eine umschriebene Altersgruppe betreffen. Das Spektrum reicht von benignen, langsam wachsenden bis hin zu hochgradig aggressiven Tumoren. Die Unterscheidung erfolgt bislang hauptsachlich nach dem histopathologischen Erscheinungsbild der Tumorzellen. In vielen dieser Tumorarten finden sich charakteristische genetische und epigenetische Veranderungen, die zunehmend Einzug in die Klassifikation finden, Aussagen uber den Krankheitsverlauf zulassen und zielgerichtete Therapiestrategien ermoglichen. Die derzeitige Behandlung besteht in den meisten Fallen in der operativen Tumorentfernung und einer Kombination von adjuvanter Strahlen- und Chemotherapie.

The flexibility offered by additive manufacturing (AM) technologies to fabricate complex geometries poses several challenges to non-destructive evaluation (NDE) and quality control (QC) techniques. Existing NDE and QC techniques are not optimized for AM processes, materials, or parts. Such lack of reliable means to verify and qualify AM parts is a significant barrier to further industrial adoption of AM technologies. Electromechanical impedance measurements have been recently introduced as an alternative solution to detect anomalies in AM parts. With this approach, piezoelectric wafers bonded to the part under test are utilized as collocated sensors and actuators. Due to the coupled electromechanical characteristics of piezoelectric materials, the measured electrical impedance of the piezoelectric wafer depends on the mechanical impedance of the part under test, allowing build defects to be detected. This paper investigates the effectiveness of impedance-based NDE approach to detect internal porosity in AM parts. This type of build defects is uniquely challenging as voids are normally embedded within the structure and filled with unhardened model or supporting material. The impact of internal voids on the electromechanical impedance of AM parts is studied at several frequency ranges.

Objectives We evaluated the feasibility of intentional transmission of HIV by means of suicide bombing and rape as a terrorist tactic in asymmetric conflicts by evaluating the recognised optimum conditions for biological warfare. We also estimated the suitability of a fourth-generation rapid test for HIV detection in the blood of dead terrorists killed in the completion of their mission. Methods The feasibility of deliberate transmission of HIV for terroristic ends was evaluated on the basis of published experience from passive biological warfare research. In addition, blood from four recently deceased HIV-positive patients and four HIV-negative control corpses, stored at 4°C in a mortuary, was analysed at 12, 24, 36 and 48 h postmortem by rapid serological testing. Results The feasibility of HIV infection for terroristic purposes was established. The fourth-generation HIV rapid test we evaluated identified all HIV-positive samples and was negative for all HIV-negative samples. Conclusions Rapid HIV testing from the remains of dead terrorists in the deployed military environment is possible. Samples should be acquired quickly, basic sample preparation is advisable and consequent decisions concerning postexposure prophylaxis should take into account the diagnostic gap in early infections.

The primary aim of this study was to compare the results of HbA1c measurements with those of an OGTT for early diagnosis of ‘silent diabetes’ in patients with coronary artery disease (CAD) undergoing angiography without prediagnosed diabetes. A secondary aim was to investigate the correlation between the extent of CAD and the glycaemic status of the patient. Data from 1,015 patients admitted for acute (n = 149) or elective (n = 866) coronary angiography were analysed. Patients with known diabetes were excluded from the study. Using the OGTT results, patients were classified as having normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes. According to the results of the HbA1c measurements, patients were classified into three groups: normal (HbA1c

The subject of this report is the characterization of plasma etch residues after a metal etch process with Cl2/BCl3 etch gases. One of the interactive factors in the removability of the residues is the photo-mask removal process (DSQ). Depending on the DSQ process the molecular structure of the residues will differ. For our findings, we used laser spectroscopy and Fourier-transformed infrared spectroscopy to obtain information about the degree of the cross-linking of the molecular structure of residues in a post-metal etch cleaning process. The post-etch cleaning is important for removing residues remaining after the metal structuring process. The main goal is to use emission spectroscopy for studying the compounds of the dry-etch related residues. Finally, it was shown that small variations in wafer treatment directly after dry-etching results in different solubilities of residues in HDA (hydroxylamine) based solutions. [1]

Allergic diseases often occur early in life and persist throughout life. This life-course perspective should be considered in allergen immunotherapy. In particular it is essential to understand whether this al treatment may be used in old age adults. The current paper was developed by a working group of AIRWAYS integrated care pathways for airways diseases, the model of chronic respiratory diseases of the European Innovation Partnership on active and healthy ageing (DG CONNECT and DG Santé). It considered (1) the political background, (2) the rationale for allergen immunotherapy across the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing. © 2016 The Author(s).

A lack of knowledge of how to design products specifically for Additive Manufacturing (AM, also referred to as “3D Printing”) is often viewed as a barrier to industrial adoption of the technology. To advance the AM workforce, the author hosted a 10-week university-wide extracurricular competition that challenged students to design, build, and operate remotely piloted ground and air vehicles made entirely via AM and a standardized electronics kit. The context of the competition was guided by the Department of Defense’s shared vision for forward deployment of AM systems to provide agile on-site part production and reduction of supply chain complexity. The competition vehicles were designed to allow future deployed military or civilian engineers to fabricate remotely-piloted vehicles while in battlefield or austere environmental conditions, such as the site of a natural disaster to search for survivors or to carry out reconnaissance missions. The competition served as unique informal learning environment that engaged over 200 students in the emerging principles of “design for Additive Manufacturing” (DfAM). In this paper, the author presents an overview of the competition structure, and the results of preliminary assessment of the students’ gains in design learning.Copyright © 2015 by ASME

Many patients with hypertension suffer from impaired glucose tolerance or type 2 diabetes mellitus. Although these diagnoses are generally simple and reliable, it is more difficult to diagnose impaired glucose tolerance. As the gold standard (oral glucose tolerance test (OGTT)) is complicated to perform, a simpler alternative would be useful. The aims of the Pre-Diabetes Score study are to correlate demographic and/or laboratory parameters that are clinically simple to determine with the results of the OGTT and to determine the diagnostic significance of the combinations of parameters with regard to impaired glucose tolerance. A total of 260 patients were included in the evaluation; 39% had impaired glucose tolerance and 12% had diabetes mellitus. A combination of HbA1c of > or =6%, a venous fasting glucose of > or =110 mg/dl, an age of > or =55 years, a systolic blood pressure of > or =140 mmHg and an enlarged waist size is highly predictive of impaired glucose tolerance.

Background: Appendectomy is a very common procedure in abdominal surgery. In numerous clinical trials it was proven that laparoscopic appendectomy outmatches conventional treatment. Nevertheless, m

Pipes made of steel 20 MnMoNi 5 5 and MnMoNiV-special melt having an external diameter of 800 mm, wall thickness of 47 mm, and length of up to 5500 mm were provided with circumferential defects of defined length and depth. They were loaded by internal pressure and a superimposed alternating bending moment. During the tests deformation and crack growth were determined in the wall thickness and circumferential direction. Pipes with an outer diameter of 226 mm and a wall thickness of 20 mm were used to investigate the leak-before-break behaviour in the dynamic sphere. These pipes were also made of steel 20 MnMoNi 5 5 and a MnMoNiV-special melt and were loaded with internal pressure and an alternating bending moment. The excitation took place at the resonance frequency of the pipes. The pipes also contained circumferential defects of defined length and depth.

High temperature seamless pipes of dimensions O.D. × T × L = 457 × 15 × 5500 mm3 made from 15 NiCuMoNb 5 material were loaded by internal pressure and a superimposed external bending moment. 27 tests with different geometries and positions of circumferential flaws in the base metal or in circumferential welds were performed at room temperature. Depending on the geometric conditions, the load bearing and failure behaviour of the investigated pipes could clearly be represented in a common failure diagram. Significant differences in maximum loads due to the position of the flaws in the structure, or whether inside or outside, could not be detected. Maximum loads were compared with calculations using applied engineering failure approaches, based on concepts of local flow stress and plastic limit load. Elastic-plastic fracture mechanics was applied to some of the component tests and the initiation and instability criteria verified.