Parametric oscillations in planetary wheel gearboxes

Разработана математическая модель параметрических колебаний в планетарных колесных редукторах (ПКР) троллейбусов. Модель учитывает циклические деформации тонкостенного обода и зубьев в зацеплении эпицикла с сателлитами. Дифференциальное уравнение колебаний эпицикла приведено к виду уравнений Матье-Хилла с переменными периодическими коэффициентами. На основании диаграммы Айнса-Стретта определены области неустойчивости параметрических колебаний "критериального элемента" – тонкостенного эпицикла для прямозубых и косозубых передач с учетом влияния зазоров в зацеплениях. Установлены диапазоны значений критических скоростей движения троллейбусов, соответствующие проявлению первых трех параметрических резонансов эпицикла ПКР в составе конструкций ведущих мостов 1-го и 3-го поколений известных фирм-производителей. Обоснован критерий виброустойчивости эпицикла, установлены расчетные значения вероятности параметрических резонансов. Теоретически подтвержден положительный эффект от применения косозубого зацепления в ПКР, что обеспечивает минимальную глубину пульсации жесткости, сужение области неустойчивости параметрических колебаний эпицикла, уменьшает вероятность зарождения и развития усталостных трещин.A mathematical model of parametric oscillations in the planetary wheel gearboxes (PWG) of the trolley buses has been developed. The model takes into account the cyclic deformations of a thin-walled rim and teeth in the meshing of the epicycle with the satellites. The differential equation of the oscillations of the epicycle is reduced to the form of the Mathieu-Hill equations with variable periodic coefficients. On the basis of the Ains-Strett diagram, regions of instability of parametric oscillations of the "criteria element" – a thin-walled epicycle for spur and helical gears are determined, taking into account the influence of gaps in the gears. The ranges of values of the critical velocities of the trolley buses corresponding to the manifestation of the first three parametric resonances of the PWG epicycle in the structure of the traction bridges of the 1st and 3rd generations of well known manufacturing companies are established. The criterion of the vibration stability of the epicycle is substantiated, the calculated values of the probabilities of parametric resonances are established. Theoretically, the positive effect of helical engagement in PWG has been confirmed, which provides a minimum depth of hardness pulsation, a narrowing of the instability region of parametric oscillations of the epicycle, reduces the probability of nucleation and development of fatigue cracks

Invasive Mold Infection of the Central Nervous System in Immunocompromised Children

Background: Due to the difficulties in the definite diagnosis, data on brain imaging in pediatric patients with central nervous system (CNS)-invasive mold infection (IMD) are scarce. Our aim was to describe brain imaging abnormalities seen in immunocompromised children with CNS-IMD, and to analyze retrospectively whether specific imaging findings and sequences have a prognostic value. Methods: In a retrospective study of 19 pediatric patients with proven or probable CNS-IMD, magnetic resonance imaging (MRI)-findings were described and analyzed. The results were correlated with outcome, namely death, severe sequelae, or no neurological sequelae. Results: 11 children and 8 adolescents (11/8 with proven/probable CNS-IMD) were included. Seven of the patients died and 12/19 children survived (63%): seven without major neurological sequelae and five with major neurological sequelae. Multifocal ring enhancement and diffusion restriction were the most common brain MRI changes. Diffusion restriction was mostly seen at the core of the lesion. No patient with disease limited to one lobe died. Perivascular microbleeding seen on susceptibility weighted imaging (SWI) and/or gradient-echo/T2* images, as well as infarction, were associated with poor prognosis. Conclusions: The presence of infarction was related to poor outcome. As early microbleeding seems to be associated with poor prognosis, we suggest including SWI in routine diagnostic evaluation of immunocompromised children with suspected CNS-IMD

The study of the mercury cycle in polar regions: An international study in Ny-Alesund, Svalbard

Mercury (Hg) is a toxic pollutant and it can be strongly accumulated in the food chain, especially in Polar Regions. This paper presents a part of the work that has been on-going for 3-4 years in Ny-Alesund, Svalbard within the frame of an international collaboration. In Ny-Alesund in spring 2003, the atmospheric chemistry of mercury has been studied so as to better understand the formation of oxidized mercury species in the atmosphere that could be deposited onto snow surfaces. The role of snow as a potential source of mercury to the atmosphere or as a sink has also been approached to better understand the behavior of this metal. Chemical and biological processes seem to play a major role in Hg storage in snow. When melting, snow could be a major source of Hg into the various ecosystems and this toxin could therefore be accumulated into the food chain

Towards Highly Automated Driving: Intermediate report on the HAVEit-Joint System

International audienceThis overview article describes the goals, concepts and very preliminary results of the subproject Joint System within the EU-project HAVEit. The goal of HAVEit is to develop and investigate vehicle automation beyond ADAS systems, especially highly automated driving, where the automation is doing a high percentage of the driving, while the driver is still meaningfully involved in the driving task. In HAVEit, an overarching architecture and several prototypes will be built up over time by manufacturers and suppliers. As a trail blazer, a Joint System prototype is under development by an interdisciplinary team of several European research institutes in order to investigate and demonstrate the basic principles of highly automated driving, which will then be gradually applied to vehicles closer to serial production. Starting with sensor data fusion, the Co-System part of the Joint Systems plans manoeuvres and trajectories, which are then used to control active interfaces and, taking into account the results of an online driver assessment, joined with the actions of the driver. While many aspects of this research undertaking are still under investigation, the concept, a first prototype and first results from a simulator evaluation will be sketched

Providing Information by Resource- Constrained Data Analysis

The Collaborative Research Center SFB 876 (Providing Information by Resource-Constrained Data Analysis) brings together the research fields of data analysis (Data Mining, Knowledge Discovery in Data Bases, Machine Learning, Statistics) and embedded systems and enhances their methods such that information from distributed, dynamic masses of data becomes available anytime and anywhere. The research center approaches these problems with new algorithms respecting the resource constraints in the different scenarios. This Technical Report presents the work of the members of the integrated graduate school

Quantum Computing for High-Energy Physics: State of the Art and Challenges. Summary of the QC4HEP Working Group

Quantum computers offer an intriguing path for a paradigmatic change of computing in the natural sciences and beyond, with the potential for achieving a so-called quantum advantage, namely a significant (in some cases exponential) speed-up of numerical simulations. The rapid development of hardware devices with various realizations of qubits enables the execution of small scale but representative applications on quantum computers. In particular, the high-energy physics community plays a pivotal role in accessing the power of quantum computing, since the field is a driving source for challenging computational problems. This concerns, on the theoretical side, the exploration of models which are very hard or even impossible to address with classical techniques and, on the experimental side, the enormous data challenge of newly emerging experiments, such as the upgrade of the Large Hadron Collider. In this roadmap paper, led by CERN, DESY and IBM, we provide the status of high-energy physics quantum computations and give examples for theoretical and experimental target benchmark applications, which can be addressed in the near future. Having the IBM 100 x 100 challenge in mind, where possible, we also provide resource estimates for the examples given using error mitigated quantum computing

An international effort towards developing standards for best practices in analysis, interpretation and reporting of clinical genome sequencing results in the CLARITY Challenge

There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance. RESULTS: A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization. CONCLUSIONS: The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups

Reaktionen des Quecksilbers und seiner Spezies in bodennahen Luftschichten der Antarktis

Den Gegenstand der vorliegenden Arbeit bilden Untersuchungen zum Verhalten atmosphärischer Quecksilberspezies in bodennahen Luftschichten der Antarktis. Dabei wurden die ersten zeitlich hochaufgelösten Langzeitmessungen atmosphärischer Quecksilberspezies an der Neumayer-Station in der Antarktis durchgeführt. Das mehr als einjährige Messprogramm konnte zeigen, dass es zu Beginn des antarktischen Frühlings an der Neumayer-Station zu starken Rückgängen der atmosphärischen Quecksilber-Konzentrationen kommt. Hg0 wird in einer Gasphasenreaktion zu Hg(II)-Spezies oxidiert. Dieses führt zu einem erhöhten Eintrag von Quecksilber in das Ökosystem der Antarktis. Mit Hilfe von Langzeitdatensätzen des atmosphärischen Quecksilbers aus der Nordhemisphäre und Messungen an Bord der "Polarstern" konnte gezeigt werden, dass es sich um ein Phänomen der Polarregionen handelt

Introduction of UAVs into Airport Ground Operations

The ongoing growth of the air transport system demands technological and operational progress. A promising field of research with potential for development in terms of capacity, safety, and environmental impact is the airport area. Several studies are currently undertaken to merge the improvements of arrival-, departure-, and surface management systems into conclusive concepts like Airport Collaborative Decision Making (A-CDM) and Total Airport Management (TAM). The target of this thesis is to propose the utilization of Unmanned Aircraft Systems (UAS) within the airport area and to put it in the context to the mentioned concepts. After presenting the state of the art in UAS-technology, applications, and the current legal situation, four use cases are discussed. These include the visual inspection of runways, bird control and a tactical guidance component for advanced surface movement guidance and control systems (A-SMGCS). The possible replacement of today’s human-driven Follow-Me-Cars by means of UAS is studied in more detail. A survey conducted among airport officials pointed out that marshalling and Follow Me procedures are rarely standardised. Instead, their non-standard character requires decision making that may be difficult to be carried out by computerised equipment. Subsequently, the other use cases with more potential for automation through UAS are elaborated in detail. These can be found in an environment with implemented surface management systems and a requirement for execution of time-based trajectories. Finally, an assessment of the risks and possible benefits of the employment of UAS within airports and a conclusive evaluation on the feasibility of the proposed UAS operation is given

Introduction of Unmanned Aerial Vehicles into Airport Ground Operations

This paper describes a concept of unmanned aerial vehicles (UAV) or rather unmanned aerial systems (UAS) to support airport processes. Three areas of application with potential for an implementation will be presented: Runway inspection, bird control, and a tactical component for future Surface Manager Systems. The paper starts by identifying airport processes, which could benefit from automated services that an un-manned and preferably highly automated aerial vehicle could provide. For that purpose, usable UAV tech-nologies, design of vehicles, and payloads were assessed. Among several basic layouts, electric multirotor technology turned out as a simple, agile, and safe platform for possible airport support functionalities. Limitations for this kind of applications exist in the battery technology, but improvements are likely in the next years to overcome these constraints. The first area of application analysed is the runway inspection. For the UAV application, the scanning of the runway for lost objects possibly harming aircraft was considered in the concept. The second UAS application is an alternative method for controlling bird populations on airports. In combination with payloads of droppable pyrotechnical cartridges and strong lasers, the birds could sustainable be scared off. The third application described is a tactical component of a high-level advanced surface movement guidance and control system (SMAN). To support pilots during the taxiing process, an UAS can be used to guide the aircraft along the taxi route. Based on requirements derived from this application, a sample UAV configuration is described with a signalling LED matrix device mounted to the vehicle through a folding mechanism