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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.

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.

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]

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.

We have monitored the perioperative changes of plasmatic values of plasminogen activator inhibitor -1 (PAI-1) in colorectal carcinoma patients depending on the stage of disease and the use of prophylactic low molecular weight heparin (LMWH).One hundred 100 colorectal carcinoma patients (64 men and 36 women) with average age of 60, in two randomized groups. All patients were surgically treated using the same technique and in all cases adenocarcinoma was confirmed. Two hours before the surgery, the first group (48 patients) received LMWH-nadroparin calcium in doses of 0.3 or 0.4 mL sc, while the second group (52 patients) received it eight hours after the surgery. Following the surgery, Nadroparin calcium was administered daily using the same dose as before. Blood samples were collected: before the surgery, 10 minutes after the first surgical incision, 8 hours after the surgery, and on the 3rd, 5th and 10 th postoperative days. The staging of the disease (according to the Dukes classification) was compared with the patients' blood plasma concentration of PAI-1. Statistical analysis using the c2 test, the LSD test, Wilcoxon and Mann-Whitney test was performed.Adenocarcinoma was patohistologicaly confirmed in all 100 subjects. According to the Dukes classification, 6 patients had stage A, 51 had stage B, and 43 had stage C. PAI-1 measurements showed that baseline measurements were within normal boundaries for both groups. Ten minutes after the first incision a sharp decline of PAI-1 values in the plasma of both patient groups was observed, which could be explained by the use due to the effect on t-PA secreted from the damaged endothelium. PAI-1 values in both groups of subjects have returned to starting (baseline) values, and remained within these values through the third, fourth and fifth measurement in both groups of patients. There was no difference between the two randomized groups which leads to the conclusion that the application of LMWH does not affect PAI-1 values. A statistically significant difference of the tested parameters according to the Dukes classification was obtained only for parameter PAI-1 for pairs Dukes A:B as well as Dukes A:C. A statistically significant correlation was found for plasma values of fibrinolysis inhibitor PAI-1 according to the Dukes classification, but it does not correlate to the tumor invasion through intestinal wall structures. The reason for the statistically significant increase of PAI-1 values in the Dukes A stage remains unclear.By activating t-PA and blocking PAI-1, Nadroparin calcium perioperatively makes the haemostasis system stable and balanced.

A post-calculation by means of four engineering approaches, based on toughness, yield stress, plastic instability and ligament stress criteria, was made of the failure pressure on 134 pipes and vessels. The calculation was assessed by comparing the calculated with the experimentally obtained results. A statistical-based evaluation was made, since the results from the calculation and the experiment are affected by natural scattering of characteristic values, such as material properties and geometrical dimensions, among others. It was possible to find for each equation an individual weighting factor, which helped to improve considerably the approximation of the calculation to the experimentally determined failure pressure.

Pipes made of 20 MnMoNi 5 5 steel and an MnMoNiV special melt, with 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. The pipes 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, and these were compared with calculated values. 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 also were made of 20 MnMoNi 5 5 steel and an 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.

Infection of G(0) arrested NIH3T3 fibroblasts with SV40 induces quiescent cells to re-enter the cell cycle and to initiate cellular DNA synthesis. We analyzed the contribution of second messengers to the stimulation of cellular DNA synthesis by SV40 infection of quiescent cells. A rapid increase in the intracellular Ca2+ ion concentration and a decrease in the intracellular cAMP concentration was found. An elevated cAMP level is incompatible with the stimulation of cellular DNA synthesis by SV40 infection of quiescent cells. Thus, overcoming the cAMP sensitive restriction point seems to be an early event after SV40 infection of quiescent cells. These data demonstrate that signal transduction mechanisms are implicated in early response to SV40 infection of quiescent cells.

The primary aim of this study was to compare the results of HbA(1c) 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 HbA(1c) measurements, patients were classified into three groups: normal (HbA(1c)5.7% [39 mmol/mol]), borderline (HbA(1c) 5.7-6.4% [39-47 mmol/mol]) and diabetes (HbA(1c) ≥6.5% [≥48 mmol/mol]).Based on the OGTT, 513 patients (51%) were classified with NGT, 10 (1%) with IFG, 349 (34%) with IGT and 149 (14%) were diagnosed with diabetes. According to HbA(1c) measurements, 588 patients (58%) were classified as normal, 385 (38%) as borderline and 42 (4%) were diagnosed with diabetes. The proportion of patients with IGT and diabetes increased with the extent of CAD (IGT ρ = 0.14, p 0.001, diabetes ρ = 0.09, p = 0.01). No differences in HbA(1c) were seen among the groups with different extents of CAD (p = 0.652).An OGTT should be performed routinely for diagnosis of diabetes in patients with CAD undergoing coronary angiography, since HbA(1c) measurement alone appears to miss a substantial proportion of patients with silent diabetes. A limitation of the study is that the OGTT was not performed before the angiography.

Das vorgestellte Projekt befasst sich mit der Entwicklung eines automatisch regulierten Bioreaktors. Dazu wurde eine UHPLC uber ein eigens entwickeltes Probenahmesystem an einen Bioreaktor gekoppelt. Die erfassten Analysendaten werden zusammen mit den Messdaten wie pH und pO2 zur Interpretation und Steuerung des Fermentationsprozesses ausgewertet. Nach einer „Anlernphase“ kann der Fermenter somit eigenstandig die Futterungssteuerung anpassen bzw. Induktionsprozesse starten. Als Beispielapplikation fur die Systementwicklung wurde Bacillus subtilis in Fed-Batch Kultivierungen gewahlt. Unter ungunstigen Milieubedingungen oder hoher Zelldichte findet die Bildung von Endosporen als Uberdauerungsform statt. Die Bildung der Endosporen soll mit dem entwickelten System kontrolliert und gezielt induziert werden.

Die Fluorphosphane Ph2PF (1), PhOPF2 (2), C5H10NPF2 (3), (Et2N)PF2 (4) und (Et2N)2PF (5) reagieren mit Me3SiN3 uber die Zwischenstufe der Azidophosphane R3−nP(N3)n zu Oligo- und Polyphosphazenen, (RR′PN)n. (iPr2N)2PF (6) wird dagegen durch Me3SiN3 zum N-silylierten Phosphazen (iPr2N)2PFNSiMe3 (7) oxidiert. tBuPh2SiN3 ist wesentlich weniger reaktiv. Im Gegensatz zu Me3SiN3 oxidiert es aber auch 5 und 1 zu (Et2N)2FPNSiPh2tBu (10) bzw. Ph2FPNSiPh2tBu. On the Reaction of Fluorophosphanes with Silylazides. The fluorophosphanes Ph2PF (1), PhOPF2 (2), C5H10NPF2 (3), (Et2N)PF2 (4), and (Et2N)2PF (5) react with Me3SiN3 via azidophosphanes R3−nP(N3)n to oligo- and polyphosphazenes, (RR′PN)n. (iPr2N)2PF (6), however, is oxidized by Me3SiN3 yielding the N-silylated phosphazene (iPr2N)2PFNSiMe3 (7). tBuPh2SiN3 is considerably less reactive. On contrary to Me3SiN3 it even oxidizes 5 and 1 forming (Et2N)2FPNSiPh2tBu (10) and Ph2FPNSiPh2tBu, resp.

The reaction of phosphorus (III) halides, R′3−n PXn (X [dbnd] F, C1), with silyl azides, R3SiN3, are described. N-silyated halo- phosphazenes, R'3−n PX [dbnd]N[sbnd]SiR3, are only obtained with fluorophosphanes having bulky substituents. Usually azidophosphanes, R'3−nP(N3)n, are formed as intermediates. These may react both as azide and as phosphane components in the Staudinger reaction forming N[sbnd]phosphany 1 phosphazenes, R'2P[sbnd]N[dbnd]PR3, or azidophosphazenes, R'3−nP(N3)n[dbnd]NY (n = 1, 2), which can be converted into di- and triphosphazenes, R' P(N[dbnd]PR3)n[dbnd]NY. A one pot procedure for preparing N[sbnd]phosphanyl phosphazenes had been developed. Replacement as well as ooxidation reactions of Cl2P[sbnd]N[dbnd]PPh3 and its derivatives are presented.

The reaction of phosphorus (III) halides, R′3−n PXn (X [dbnd] F, C1), with silyl azides, R3SiN3, are described. N-silyated halo- phosphazenes, R'3−n PX [dbnd]N[sbnd]SiR3, are only obtained with fluorophosphanes having bulky substituents. Usually azidophosphanes, R'3−nP(N3)n, are formed as intermediates. These may react both as azide and as phosphane components in the Staudinger reaction forming N[sbnd]phosphany 1 phosphazenes, R'2P[sbnd]N[dbnd]PR3, or azidophosphazenes, R'3−nP(N3)n[dbnd]NY (n = 1, 2), which can be converted into di- and triphosphazenes, R' P(N[dbnd]PR3)n[dbnd]NY. A one pot procedure for preparing N[sbnd]phosphanyl phosphazenes had been developed. Replacement as well as ooxidation reactions of Cl2P[sbnd]N[dbnd]PPh3 and its derivatives are presented.

The title compound (1a) was prepared by a two-step procedure via an organomercurial. Both 1a and its 11,11-difluoro analogue are crystalline solids that were fully characterized. The tetraiodide 1a is unusual in that the aromatic character of the π periphery is almost destroyed as determined from ring current effects on the 11,11 hydrogen atoms. The crystal structure of 1a is reported and it bears out the «localization» of the π electrons with a concomitant opening of the transannular bridge angle

Pipes made of steel 20 MnMoNi 5 5 having an external diameter of 800 mm, wall thickness of 47 mm and length of 5 m were provided with circumferential flaws in defined length and depth. They were loaded simultaneously by internal pressure, alternating or pulsating external bending moment. Deformation and the crack growth were determined in the wall thickness and circumferential direction and compared with calculated values.

Pipes with an outer diameter of 406 mm, a wall thickness of 12.5 mm and a length of 1000 mm were tested under tensile loading. They were prepared with part-circumferential flaws of uniform length but different depth. A fine grained constructional steel having a low upper shelf ISO-notch impact energy ≤ 50 J at test-/room temperature was chosen as test material. With the aid of the test results, the predictions of established approximation methods for the calculation of maximum load and, as far as possible, the load at crack initiation were checked. The applied methods which are based on modelling of the pipe by means of flat tensile specimens proved to be unsuitable for estimation of the maximum load. The methods for maximum load evaluation which had been specially developed for pipe geometries showed mostly a good agreement with the experiments. The calculations based on elastic-plastic fracture mechanics gave results which underestimated maximum load, whilst the crack initiation loads were to some extent overestimated.

Stress-corrosion cracking (SCC) studies were conducted in the following commonly used pressure vessel steels: ASTM A533 Grade B Class 1 (A533-B-1) plate and a fabricated forging that is equivalent in chemistry and thermomechanical processing to American-made ASTM A508 Class 2 (A508-2) forgings. The purpose of these studies was to determine the response of the materials in a simulated pressurized-water reactor environment. Round tensile specimens were bolt-loaded to 75 to 80 percent of yield and left in the water at 93°C for 2000 h. At the end of this time period, the specimens were taken out of the water, unloaded, and examined by scanning electron microscopy (SEM) and by energy-dispersive X-ray analysis. The specimen cut from A533-B-1 plate did not have any cracks as a result of the SCC tests. Several cracks, some of which were visible with the unaided eye, had developed in the specimen that was cut from the A508-2 forging. The polished and etched sections of the specimen that showed SCC, when examined with the SEM, revealed the presence of many microcracks starting from the outside surface and propagating along either inclusion-matrix or carbide-matrix interfaces; the corresponding microstructure was mostly pearlitic. The microstructure of the specimen that did not crack was bainitic; it had fewer inclusions and carbide particles, and no microcracks were observed. When the fracture surfaces of the larger cracks were examined by SEM, they revealed a cleavage-like failure propagating along inclusion bands. X-rayimage scansand energy spectra of these hands showed thatthey were silicate and manganese-sulfide inclusions. A hydrogen-assisted cracking model has been proposed to explain the experimental results on A508-2 forging. Produced by a cathodic reaction and aided by the stress fields, hydrogen diffuses ahead of the crack tip to the inclusion sites. This causes a preferential decohesion at the inclusion-matrix interfaces and subsequent cracking along inclusion bands. The absence of stress-corrosion cracking in A533-B-1 plate tested under identical experimental conditions is due mainly to fewer inclusion and carbide particles and to the more refined bainitic microstructure of this steel. This type of microstructure is less susceptible than the mainly pearlitic microstructure found in A508-2 forging to hydrogen-assisted cracking.