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ZusammenfassungDer radiologischen Bildgebung der vertebralen Infektionen kommt eine zentrale Rolle in der Initialdiagnostik wie auch der Verlaufsbeurteilung zu. Der Artikel beschreibt die verschiedenen Möglichkeiten der Bildgebung, deren Vorteile und Grenzen. Der Schwerpunkt liegt hierbei auf der pyogenen Spondylodiszitis. Daneben werden die typischen bildmorphologischen Kriterien unter Berücksichtigung verschiedener Erreger erläutert. Zusätzlich befasst sich der Artikel mit den möglichen Differenzialdiagnosen.

Advanced unmanned aerial vehicles (UAV) become increasingly popular inter alia as low-risk demonstration platforms for new aircraft-design concepts and technologies in aviation industry and research. Due to the experimental nature and complexity of such systems, flight tests regularly require the support of design engineers who monitor and assess the behavior and performance of the aircraft and its subsystems while it is in flight. At the Institute of Flight System Dynamics of the Technical University of Munich (TUM-FSD), the flight guidance and control system for the novel ‘SAGITTA Demonstrator’ UAV has been developed. It enables fully-automatic operation of the aircraft, which has been successfully demonstrated during the maiden flight campaign in July 2017. This paper presents the challenges of real-time monitoring of a fully-automatic UAV and explains how they were solved within the maiden-flight test campaign of the SAGITTA Demonstrator. The ground station setup and displays that were applied to supervise the flight guidance and control system are presented. Experiences gained during the flight tests are gathered and recommendations derived.

At the Institute of Flight System Dynamics of the Technische Universitat Munchen (TUM), a digital auto flight system for a fixed-wing Unmanned Air Vehicle (UAV) featuring a novel diamond-shaped configuration is designed, implemented and tested up to its first flight. The capabilities of the UAV comprise a fully automated flight, including ground control for centerline tracking and runway alignment during automatic take-off and landing. This paper presents the approach concerning the development of the model-based designed ground controller for the diamond-shaped UAV. The respective landing gear model required for control law synthesis has been implemented by the Institute of System Dynamics and Control of the German Aerospace Center (DLR) utilizing available configuration and test-bench data. The focus within this paper is set on the dedicated ground controller design based on the associated landing gear model, culminating in promising real live taxi-test results by exciting significantly the ground controller by lateral offset commands.

This article presents the development of fly-by-wire control laws used for the high-fidelity simulation of a new transport category aircraft. Beyond structural and gain design aspects for normal operations, envelope protections and limitations as well as mode transition issues are also addressed. As the control system is to be adjusted to changing aircraft datasets at different levels of fidelity, particular emphasis has been put on a high level of automation in gain design and system assessment routines. For lateral dynamics, eigenstructure assignment is used as the design methodology whereas pole placement is used for the pitch axis.

The aim of the study was to compare prospectively magnetic resonance cholangiography (MRC) and magnetic resonance imaging (MRI) with endoscopic retrograde cholangiography (ERC) in the diagnosis and staging of Klatskin tumours of the biliary tree (hilar cholangiocarcinomas). Forty-six patients with suspected Klatskin tumours of the biliary tract underwent MRI and heavily T2-weighted, non-breathhold, respiratory-triggered fast spin-echo MRC. Forty-two patients underwent ERC within 24 h; in four patients, ERC was not feasible, and percutaneous trans-hepatic cholangiography (PTC) was carried out instead. Two independent investigators evaluated imaging results for the presence of tumour, bile duct dilatation, and stenosis. Clinical and histopathological correlation revealed Klatskin tumours in 33 patients. MRI revealed a slightly hyperintense signal of infiltrated bile ducts in T2-weighted fast spin-echo sequences. The malignant lesion was regularly visualized as a hypointense area in T1-weighted gradient-echo sequences with substantial contrast enhancement along the involved bile duct walls. MRC revealed the location and extension of the tumour in 31 of 33 cases correctly (sensitivity 94%, specificity 100%, diagnostic accuracy 95%). In 27 of 31 cases, ERC enabled accurate staging and diagnosis of Klatskin tumours with a sensitivity of 87%. ERC and PTC combined yielded a sensitivity of 84% and a specificity of 97%. Tumours were grouped according to the Bismuth classification, with MRC allowing correct identification of type I tumour in seven patients, type II tumour in four patients, type III tumour in 12 patients, and type IV tumour in ten patients. MRC provided superior visualization of completely obstructed peripheral systems. MRC in combination with MRI is a reliable non-invasive diagnostic method for the pre-therapeutic staging of Klatskin tumours.

The development of a novel aircraft configuration is typically accompanied by high technical risks. In order to ensure the success of such a development, a risk reduction phase must be considered in the design cycle. The paper at hand gives insight into the activities related to flight dynamics and control that have been performed during the risk reduction phase of a novel diamond-shaped UAV, the so-called SAGITTA Demonstrator. In particular, the main design drivers for the configuration's Flight Control System are provided and details on the inherent lateral dynamics and worst case stabilization capability are presented. Furthermore, a preliminary controller structure that is suitable to meet the requirements and an appropriate gain design method are proposed. The resulting preliminary closed-loop system is analyzed in frequency domain (e.g. by means of Nichols charts) and time domain (i.e. gust response). By the activities, summarized as Controllability Study, main requirements are validated and significant development risk reduction is achieved.

Results from a joint research program of the Institutes of Fluid Dynamics and of Flight Mechanics and Flight Control of the Technical University of Munich on a two-stage space transportation system are presented. The unsteady aerodynamics resulting from an orbital stage at stage separation e ow conditions at Mach number 6.8 are e rst discussed. Unsteady e owe elds associated with yaw and roll oscillations of the orbital stage at a certain distanceabovethecarrierstageareinvestigated.Thecalculationsarebased ona e nitevolumemethodforreal-time solutions of the unsteady Euler equations. Theresultsfocus on pressuredistributions and aerodynamic coefe cients providing an essentialmeansforcarrying outstabilityand control investigations.Inthesecond part, e ightmechanics stability and control problems are addressed considering key issues of lateral ‐directional dynamics. Inherent vehicle characteristics can show specie c stability and e ying quality dee ciencies in hypersonic e ight, concerning a partially unstable dutch roll mode with high roll ‐yaw coupling and weak roll damping. There is also a coupling of the roll and spiral poles for certain cone gurations, yielding a slow, eventually unstable oscillation called lateral phugoid. Reasons and effects for the stability dee ciencies are discussed, including conditions of existence for the lateral phugoid.

Compared to common transport aircraft (airliners), it is fact that the General Aviation (GA) sector exhibits a significant higher rate of accidents. Even though the sources are manifold, two main reasons may be identified. First, General Aviation Pilots generally have a relative low training level and small number of flight hours compared to airliner pilots and thus, their flight experience and hazard awareness is consequently limited. The second reason is, that recent transport aircraft feature a significant higher technical standard possessing various beneficial pilot assistant systems supporting the pilot to fly the aircraft safely at the same time reducing pilot’s workload extensively. The most vital assistant systems, well-known as Fly-by-Wire Flight Control Systems (FbW FCS), provide directly the appropriate control deflections according to the pilot’s commands and (measured) flight condition and thus are capable to assume important safety enhancing tasks. In addition to ensuring excellent and homogenized flying/handling qualities along the whole envelope, they offer functionalities like pilot input monitoring, provision of warnings plus active envelope protection yielding a substantial increase of passenger, crew and aircraft safety towards the key objective "carefree handling". Unfortunately, this valuable safety increase did not find its way into the general aviation sector although it is standard in current transport planes and modern business jets. This is due to the tremendous cost of typical Fly-by-Wire control technology always requiring complex redundancy and reversionary systems to fulfill the strict certification requirements. However, in order to accomplish an equivalent safety enhancement for GA aircraft and thus to diminish the high accident rates and so to protect human lives, the well-proved beneficial features of active Flight Control Systems have to be made available and affordable for them.

The unique dynamic coupling effects between airframe, flight control system, and the pilot of modern, highly or super-augmented aircraft introduce new stability and handling qualities problems which do not occur on conventional airplanes. In particular, phenomena leading to a destabilization of the closed-loop system consisting of the airframe, the control and stability augmentation system, and the pilot, triggered by an undesired and unexpected interaction between pilot and augmented aircraft dynamics are known to be very dangerous for the aircraft and crew. They are commonly referred to as Pilot Involved or Pilot-In-the-Loop Oscillations. This paper focuses on the enhancement of the so called Open-Loop-Onset-Point-criterion, originally developed to predict PIO-susceptibility due to nonlinear effects such as position and non-phase-compensated rate limiting. The criterion is modified to also cover phase-compensated rate limiters, which are now commonly found in modern flight control systems.

For today’s highly augmented fighter aircraft, the aircraft dynamics are specifically tailored to provide Level 1 handling qualities over a wide regime of the service flight envelope. This requires a profound understanding of the human pilot to assure that stability margins of the airframe plus controller dynamics are sufficient to accommodate the additional pilot dynamics introduced into the system during closed loop tasks. Whereas the mathematical formulations of the airframe and controller dynamics are reasonably exact, the human pilot remains to be the most unpredictable element in the Pilot Vehicle System. In the past decades various pilot models have been developed in conjunction with analytical handling qualities and Pilot Involved Oscillations prediction criteria, mainly focusing on air-to-air tracking tasks. This paper focuses on the development of a novel flight test technique, which allows the identification of the pilot dynamics during air-to-surface aiming tasks. During an extensive flight test campaign, data was gathered and processed, using state of the art systemidentification techniques to derive a mathematical model of the human pilot during air-tosurface tracking tasks. Flight test and model-based data are compared with each other to support the validity of the developed pilot models.

[Abstract] Due to the continuously increasing design requirements on modern aircraft the robustness properties of their flight control systems against multiple model uncertainty becomes a more and more important issue for flight control system certification and flight clearance, particulary in the case of an unstabel aerodynamic basic design. Most classical approches (like stability margins in the Nichols Chart) only provide incomplete information about the qualitative and quantitative degree of robustness. Therefore, an innovative approach for robustness analysis of the primary control laws of a modern jet trainer will be presented here which uses the structured singular value (SSV) and a physically motivated parametric uncertainty model. The methodology is applied to both the longitudinal and lateral basic controller and shows a direct and exact way from the definition of parametric uncertainties to an uncertain system model suitable for -analysis. Particularly, the introduction of a trim point uncertainty emphasizes the davanced character of this analysis method by incorporating the dependence of the control loop parameters (plant and controller gains) on the current trim point into the uncertainty model. Consequently the analysis of the controller can be accomplished for entire regions of the flight envelope in a single robustness test. Therefore, the proposed approach demonstrates the possibility of substituting the conventional proceedures for proving controller robustness by a more efficient methodology.

Data on magnetic resonance cholangiopancreatography with secretin stimulation (S-MRCP) for the assessment of exocrine pancreatic insufficiency (EPI) are limited. We compared pancreatic function tests with the findings of S-MRCP in patients with chronic pancreatitis (CP) and disease controls.S-MRCP was performed in 23 patients (18 CP, 5 disease controls). MRCP images were analyzed for secretin-induced duodenal liquid filling (0=no filling; 1=duodenal bulb; 2=up to lower flexure; 3=beyond lower flexure). EPI was evaluated by fecal elastase, fecal fat concentration, and a 13C mixed chain triglyceride breath test. Clinically relevant EPI was stated if 2 of 3 tests were pathologic.EPI was diagnosed in 10 of 18 patients with CP. Patients without EPI showed either grade 2 (n=4) or grade 3 (n=9) duodenal filling, whereas only 1/10 patients with EPI showed grade 3 duodenal filling. Sensitivity and specificity of S-MRCP for the diagnosis of EPI were 69% and 90%, respectively.Assessment of duodenal filling should be performed in patients who undergo S-MRCP for the evaluation of pancreatic morphology. However, minor degrees of duodenal filling are equivocal and require further diagnostic evaluation.

To define the maximum tolerated dose (MTD) of hepatic intraarterial chemotherapy with gemcitabine, administered with and without starch microspheres, in patients with inoperable intrahepatic cholangiocarcinomas and liver metastases of pancreatic carcinomas.Gemcitabine was administered on days 1 and 8 with intervals of 2 weeks between the cycles. In group A the initial gemcitabine dose of 1,000 mg/m(2) (without microspheres) was increased in 200-mg/m(2) steps up to a maximum dose of 2,000 mg/m(2). In group B the MTD with microspheres was assessed by giving an additional microsphere dose according to tumor extent and body weight, increasing gemcitabine starting from a dose-step below the MTD with microspheres. The MTD was evaluated via clinical and laboratory findings.Twenty-four patients were enrolled (12 males, 12 females, mean age 59.17 years; intrahepatic cholangiocarcinoma: n = 17, liver metastases of pancreatic carcinoma: n = 7). The MTD of gemcitabine without microspheres was reached at 1,400 mg/m(2), and of gemcitabine with microspheres at 1,800 mg/m(2). The comparative evaluation revealed statistically significant better data for the time to progression (p0.01) and survival for the group with microspheres (6.8 and 20.2 months) in comparison to the group without microspheres (4.2 and 13.5 months).This clinical study indicates that the intraarterial application of gemcitabine with doses higher than the recommended 1,000 mg/m(2) is well tolerated if combined with microspheres, and yields respectable results in patients who do not respond to systemic chemotherapy.

Well done designs and well equipped machines are only half the way to reproducible and stable quality of a coating production. To achieve this aim it is also necessary to have a complex production management system to one's disposal, including recipe management, machinery management and quality assurance. Most production errors and rejects are caused by wrong handling, which can be leaded back to a lack of actual information, or by errors of measurement-systems and by fails of equipment during a coating process. So, the very simple rules one has to observe are: 1.) Transfer really all necessary information about the process to operator and to machine and force the operator to read this information, by using an online-checklist during charging a batch. 2.) Never trust in a single measurement-result of your plant-equipment, without a cross-check to independent generated data's; redundancy is the magic word for process-assurance. 3.) Check the status of your equipment as often as possible; integrate a maintenance plan in your plant control and let the machine record all parameters, which are relevant for wearing parts or media. This essay will show, how to organize your recipe parameters, transfering information to plant and operator, methods for redundancy and cross-checks of parameters, and an example for a complex coating system based on a LH-A700QE.

The performance of UV photolithography lens-systems with usually several ten optical components is limited by both the quality of the substrates and by the quality of the optical coatings. The key problems are the quality of the reflectance over large and strongly curved surfaces, the absorption and scatter losses and the behavior during heavy UV irradiation in production lines.

Hypersonic vehicles feature unique stability and control properties due to specific aerothermodynamic and propulsive characteristics which are not existent with conventional airplanes. Simplified models may be used to provide an insight into the inherent dynamics. Furthermore, they can be used to develop basic control systems to counter and eliminate the deficiencies present with the inherent dynamic behavior of the system. However, more elaborate models are required to cover complex configuration specific aspects like engine or sensor dynamics or other effects present with real aircraft configurations. This paper describes an attempt to implement a flight dynamics modeling environment capable of treating more complex vehicle dynamics. Another focus of the paper is to present approaches for increasing the level of automation of flight dynamics and control design tasks for hypersonic vehicles in order to allow analyzing the maturity of the control concepts developed for the simple models in a more realistic environment.

A Fly-by-Wire like Flight Control System for small general aviation aircraft designed for excellent flying qualities and pilot assistance with particular emphasis on acceptable development and especially certification efforts (cost-benefit ratio) is considered. The manifold benefits of advanced Active Fly-by-Wire Flight Control Systems within modern transport aircraft featuring a wide range of functionalities and applications are undisputable. They represent an effective means of reducing pilot's workload significantly, monitoring pilot’s inputs, providing warnings and protections and hence, increasing the passenger, crew and aircraft safety (carefree handling). However, the general aviation aircraft sector is still missing such Active Flight Control Systems because of their tremendous (development, system/hardware and certification) cost which can easily exceed the actual airframe cost of the small aircraft several times. Affordable Fly-by-Wire technology for small aircraft can be achieved by using a Hybrid Control System which combines additional (limited) electrical actuated control surface deflections commanded by the Flight Control Computer together with retaining a (full-authority) permanent mechanical direct link between pilot inceptor and the control surface via a mechanical mixing unit. This approach offers the opportunity of utilizing the benefits of state of the art Fly-by-Wire control technology simultaneously enhanced by the reliability of conventional control systems and thus, reducing certification effort and cost dramatically. The Hybrid Fly-by-Wire like control concept discussed is integral part of a joint Technology Research project concerning upcoming future small aircraft representing a cooperation of an Austrian aircraft manufacturer and Technische Universitat Munchen.

ठThe paper presents the development of a Flight Control System for the lateral dynamics of a transport aircraft to be used for simulation analys is. For a manufacturer-independent evaluation of the handling characteristics of a future transport aircraft, it is inevitable to replicate its flight control system as close as possible. While some data on the basic design characteristics of the flight control system of the real aircraft could be obtained, almo st no information was available concerning its internal implementation. Thus, own control laws have been implemented. As both the fidelity of the flight simulation model as well as the underlying d ata are changing quite rapidly, robust routines for automated gain and filter computation have been developed, accounting for handling qualities, stability and robustness requirements which can be easily stated in definition files. Much attention i s drawn to the high level of automation in gain desig n and the flexibility in specifying the characteristics of the closed-loop system as those features on the one hand allow the system to be use d during all stages of the project and on the other h and provide the capability to analyze the impact of different design requirements on the overall charac teristics of the system. For achieving appropriate dynamics characteristics, eigenstructure assignment is used. The system is augmented by limitations as well as compensations.