Alternatives Verfahren für die Störfestigkeitsprüfung von elektronischen Messwandlern in Schaltanlagen

Mittelspannungsschaltanlagen ermöglichen in Energieversorgungsnetzen eine Änderung der Netztopologie, bzw. den selektiven Schutz des Netzes im Fehlerfall. Schalthandlungen in den Mittelspannungskreisen verursachen Vorund Rückzündungslichtbögen, die transiente Überspannungen mit kurzen Anstiegszeiten zur Folge haben. Diese breitbandigen Transienten koppeln auf die Niederspannungsseite über und wirken dort auf die elektronischen Schutzund Steuereinheiten (engl. intelligent electronic devices, kurz: IEDs) ein. Um das Risiko einer Fehlfunktion des Netzschutzes zu minimieren sind für die analogen Eingänge eines IEDs spezielle Typprüfungen vorgesehen. Durch die zunehmende Verbreitung von elektronischen Messwandlern nach IEC 60044-8, wie z.B. Rogowski-Sensoren, ergeben sich Unsicherheiten in Bezug auf das genormte Prüfverfahren. In diesem Beitrag werden die Unterschiede zwischen den konventionellen Stromwandlern (engl. current transformer, kurz: CT) und der neuen Technik vorgestellt. Beide Technologien werden hinsichtlich der Koppelpfade für Störgrößen verglichen. Anschließend werden das genormte Prüfverfahren und die Probleme bei dessen Anwendung auf IEDs mit elektronischen Messwandlern beschrieben. Es wird ein alternatives Prüfverfahren vorgeschlagen, dass die reale Beanspruchung für hochohmige Eingänge besser nachbildet. Die Vergleichbarkeit der Störpegel bei Prüfung und realem Schaltanlagenbetrieb wird dabei im Zeitund Frequenzbereich gezeigt

Low-Flow Anaesthesia: Does it have Potential Pharmacoeconomic Consequences?

Healthcare reform has placed increasing pressure on anaesthetists to consider the costs of current anaesthesia strategies. Although the cost of anaesthesia constitutes only a small proportion of total healthcare costs, anaesthetic drug expenditures have been a focus of cost-containment efforts. Low-flow anaesthesia is a simple method of reducing the fresh gas flow rate for anaesthetic gases during inhalational anaesthesia. A knowledge of the pharmacokinetic behaviour of inhaled anaesthetics and the use of modern equipment and monitoring technology meet the requirements for safe application of this anaesthetic technique. Millions of patients receive general anaesthesia each year, and thus the use of this technique could generate substantial savings in anaesthetic drug expenditure without reducing the patient's comfort or increasing adverse events. The new inhaled anaesthetics desflurane and sevoflurane, which have low tissue solubility, provide promising options when used in low-flow anaesthesia. Apart from the economic advantages, low-flow anaesthesia helps to reduce environmental pollution and is associated with several physiological benefits for the patient. Low-flow anaesthesia is a simple but highly effective method of cost minimisation that can be applied to a large number of patients without any compromise in patient care or safety.Anaesthesia, Anaesthetics, Cost analysis, Desflurane, Pharmacoeconomics, Sevoflurane

Development of Innovative Services Enhancing Interoperability in Cross-Organizational Business Processes

Part 2: Full PapersInternational audienceThis paper presents the vision and ongoing results of the COIN (FP7-216256) European project for the development of collaborative and cross-organizational business process interoperability. Services for selectively publishing parts of private business processes are developed which enable the creation of a cross-organizational business process (CBP). Gap detection services provide analysis of the CBP with regards to interoperability gaps like potential deadlocks

Burden between Undersupply and Overtreatment in the Care of Primary Spontaneous Pneumothorax

Background The optimal treatment of primary spontaneous pneumothorax (PSP) is still controversial. The purpose of this study was to analyze the incidence of recurrence, the recurrence-free time, and to identify risk factors for recurrence after PSP. Methods We performed a retrospective analysis of 135 patients with PSP who were treated either conservatively with a chest tube ( n =87) or surgically with video-assisted thoracoscopic surgery (VATS; n =48) from January 2008 through December 2012. Results In this study, 101 (74.8%) male and 34 (25.2%) female patients were included with a mean age of 35.7 years. The indications for surgery included blebs/bullae in the radiological images ( n =20), persistent air leaks ( n =15), or the occupations/wishes of the patients ( n =13). A first ipsilateral recurrent pneumothorax (true recurrence) was observed in 31.1% of all patients (VATS: 6.25%, conservative: 44.8%). Including contralateral recurrence, the overall first recurrence rate was 41.3% (VATS: 14.6%, conservative: 57.5%). The recurrence-free time did not differ significantly between the treatment groups ( p =0.51), and most recurrences were observed within the first 6 months after PSP. Independent risk factors identified for the first recurrence were conservative therapy ( p =0.0001), the size of the PSP (conservative; p =0.016), and a body mass index <17 (VATS; 0.022). The risk for second and third recurrences of PSP was 17.5 and 70%, respectively, for both treatment groups, but it was 100% after conservative therapy. Conclusion Surgery for PSP should be selected based on the risk factors and the patient's wishes to prevent first recurrences but also to avoid overtreatment. The treatment of first and subsequent PSP recurrences should be with surgery since conservative treatment is associated with a 100% recurrence rate