Post-laparotomy haemoptysis due to broncho-abdominal fistula caused by retained abdominal surgical swab

The case presented describes the migration of a surgical swab across the left hemidiaphragm over four years. The patient had at least two episodes of haemoptysis in that period and was misdiagnosed and treated for Pulmonary Tuberculosis. When the proper diagnosis was made and a lobectomy was planned for removal of the swab, the act of anaesthesia revealed a major bronchoabdominal fistula that was resolved by simply isolating that lung with an endobronchial tube. According to our search, such a left-sided broncho-abdominal fistula has, to date, not been described in the literature.Keywords: broncho-abdominal fistula, gossypibom

Reducing Friction and Leakage by Means of Microstructured Sealing Surfaces – Example Mechanical Face Seal

By defined structuring of sliding surfaces at dynamic contact seals friction and leakage can be reduced. Compared to macro-structures, micro-structures have the advantage of a quasi-homogeneous influence on the fluid behavior in the sealing gap. The development of suitable microstructures based on prototypes, whose properties are studied on the test bench, is very expensive and time-consuming due to the challenging manufacturing process and measuring technologies, which are necessary to investigate the complex rheological behavior within the sealing gap. A simulation-based development of microstructured sealing surfaces offers a cost- and time-saving alternative. This paper presents a method for simulative design and optimization of microstructured sealing surfaces at the example of a microstructured mechanical face seal

Использование средств e-learning в высшей школе

Применение информационных технологий в образовательном процессе делает его более увлекательным и более эффективным, позволяет формировать творческое мышление, стимулирует студентов к саморазвитию и самостоятельности. В статье раскрывается потенциал средств электронного обучения в оптимизации учебного процесса в высшей школе

Reliability Evaluation of Drivetrains: Challenges for Off‐ Highway Machines

Downtime of mobile machinery used in fields like construction, earthmoving or mining usually leads to an instant halt of an entire process and can even endanger entire operations. To meet the customer’s requirement for high availabilities of their equipment, safeguarding the reliability of overall systems and components is necessary. Since life expectancy of systems and its components strongly depends on the experienced load history, this information needs to be available as accurately as possible to allow reliable lifetime calculation results. Due to the wide range of machines and applications of off‐highway machines, determining representative loads is especially challenging. The challenges, in determining both load cycles for the entire system and local component loads, are discussed in this work, along with approaches to face them. Additionally, a method is described, which allows users to quantitatively calculate life expectancy of technical systems in both the concept phase and the later stages of the product life cycle. In the end, two examples are presented in which exemplary challenges are faced

Branchenübergreifendes Benchmarking von variantenreichen Produktportfolios auf Basis von Produktstrukturen

Für die Messung von Prozessabläufen wie der Beschaffung (Supply Chain), der Arbeitsvorbereitung und der Produktion werden spezifische Unternehmenskennzahlen genutzt. Diese Key Performance Indicator (kurz: KPI) bilden häufig jedoch ausschließlich finanzielle Aspekte für eine unternehmensinterne Überwachung ab und berücksichtigen nicht den Entwicklungsprozess. Alternative Ansätze verwenden aus dem Expertenwissen der Mitarbeiter zusammengetragene Informationen, die durch ihre Subjektivität die Reproduzierbarkeit erschweren. In Abgrenzung zu bestehenden Konzepten wird in diesem Beitrag die Effizienz-Bewertung von variantenreichen Produktportfolios auf Basis der Produktstrukturen sämtlicher realisierter Erzeugnisvarianten beschrieben. [... aus Punkt 2

Microstructural and Chemical Characterization of the Tribolayer Formation in Highly Loaded Cylindrical Roller Thrust Bearings

Zinc dithiophosphates (ZDDP) have been widely applied in automobile industry for over 70 years as a lubricant additive for wear protection. Tribolayers have been described as blue- and brown-colored layers on surfaces observed by microscopical observation or even bare eye presumably as a consequence of layer thickness or chemical composition. However, the reaction pathways of ZDDP tribolayers are still not yet fully understood. In the present study, the difference between the blue- and brown-colored tribolayers has been revealed by high resolution methods in cylindrical roller thrust bearings at relatively high contact pressures of around 1.92 GPa. After running a FE8 standard bearing test with a normal load of 80 kN and a temperature of 60 °C, said tribolayers could be identified on the bearing surfaces. By using Raman spectroscopy, it could be shown that the blue-colored layers are enriched by FeS and ZnS whereas the brown-colored layers show a significant amount of Fe3O4. This is an interesting finding as it clearly shows a correlation between the color appearance of the films and the chemical composition besides potential film thickness variations. Finally, transmission electron microscopy verified the amorphous nature of the formed tribolayer which is in a good agreement with literature

Effect of structure on tribomechanical properties of sintered (Al-12Si)-Sn composites

The structure, mechanical and tribological properties of sintered (Al-12Si)-xSn composites were investigated in the present study. The composites were obtained by sintering of the briquettes made of aluminum (Al-12Si) and tin powders mixture. It was found that the hot densification substantially increases the strength of sintered composites and also makes much higher their wear resistance under the dry friction against a steel counterbody. The mechanical properties of the obtained materials slowly decrease with an increasing of tin content up to 40 wt. %, while their wear resistance increases