Photocatalytic generation of hydrogen using iron-containing metal-ceramic composites with simultaneous degradation of organic compounds

The phase composition of composites was investigated, which were received by nitriding the ferroboron and ferrosilicoaluminium by the SHS method and modified with additives of schungite and titanium. Photocatalytic activity of composites in combined processes of hydrogen generation and degradation of organic substances was investigated. The activity of composites is related to the presence of a phase of metallic iron in their composition, concentration in the system of activator reagents (Н[2]О[2], Н[2]С[2]О[4]), and also with the presence of high energy-gap semiconductor in the composite matrix

Pretty Understandable Democracy 2.0

The technological advance is entering almost all aspects of our everyday life. One interesting aspect is the possibility to conduct elections over the Internet. However, many proposed Internet voting schemes and systems build on unrealistic assumptions about the trustworthiness of the voting environment and other voter-side assumptions. Code voting -- first introduced by Chaum [Cha01] -- is one approach that minimizes the voter-side assumptions. The voting scheme Pretty UnderstandableDemocracy [BNOV13] builds on the idea of code voting while it ensures on the server-side an arguably practical security model based on a strict separation of duty, i.e. all security requirements are ensured if any two components do not collaborate in order to violate the corresponding requirement. As code voting and strict separation of duty realizations come along with some challenges (e.g. pre-auditing phase, usability issues, clearAPIs), the goal of our research was to implement Pretty UnderstandableDemocracy and run a trial election. This paper reports about necessary refinements of the original scheme, the implementation process, and atrial election among the different development teams (each team being responsible for one component)

Untersuchung des transienten Motorbetriebs mittels minimalinvasiver optischer Diagnostik

Das Ziel der vorliegenden Dissertation ist ein tieferes Verständnis der innermotorischen Prozesse im transienten Motorbetrieb hinsichtlich der Entstehung von Ruß zu entwickeln. Im Fokus der Untersuchungen steht der Vergleich von stationären und transienten Betriebspunkten hinsichtlich der Zylinderinnenströmung, Flammenausbreitung und der Entstehung von Ruß aus verschiedenen Rußquellen. Zu Beginn der Arbeit wurde ein Einzylindermotor mit einem minimalinvasiven optischen Zugang in der Laufbuchse für ein Laserlichtschnitt sowie einem endoskopischen Zugang im Zylinderkopf realisiert und für den transienten Motorbetrieb ertüchtigt. Die Prüfstandsperipherie ermöglicht die Abbildung realer transienter Manöver des entsprechenden 4-Zylinder-Motors und mittels automatisierter Prüfabläufe konnten reproduzierbare Wiederholungen der Transienten gemessen werden. Die applizierte laserbasierte Diagnostik ermöglichte die zeitaufgelöste Erfassung der innermotorischen Prozesse, sprich die endoskopische planare particle image velocimetry (PIV) zur Vermessung der Zylinderinnenströmung sowie die endoskopische breitbandige Visualisierung der Chemilumineszenz zur Detektion der Flammenausbreitung und des Rußeigenleuchtens als Maß für die Rußpartikelanzahlemissionen. Die endoskopische PIV wurde mittels einer Vergleichsmessung an einem optischen Motor gleicher Motorgeometrie verifiziert. In der vorliegenden Arbeit zeigte sich eine hohe Datenqualität der endoskopischen PIV. Aus den Bilddaten der Chemilumineszenz und des Rußeigenleuchtens wurden Kenngrößen durch Bildbearbeitung extrahiert und mittels aus der Literatur bekannten Zusammenhängen mit motorischen Parametern verifiziert. Die umfangreichen Datensätze wurden mittels im Rahmen der Arbeit entwickelten Bildbearbeitungs- und Auswertealgorithmen prozessiert und statistisch analysiert. Die Untersuchung der Zusammenhänge zwischen den einzelnen Parametern erfolgte für alle Manöver anhand von Korrelationsanalysen, der Visualisierung mittels Streudiagrammen und der Methode der Korrelationsfelder. Ein applizierter Lastsprung mit konventionellen Ventilsteuerzeiten zeichnete sich durch einen Saugrohrdruckgradienten innerhalb der transienten Zyklen aus. Die Analyse der phasengemittelten Vektorfelder zeigte im Rahmen der Messunsicherheit keinen Einfluss des Gradienten auf die Strömung im Ansaug- und Kompressionstakt. Die transienten Betriebspunkte resultierten im Mittel in höheren Rußpartikelemissionen als die entsprechenden stationären Betriebspunkte. Bei der Korrelationsanalyse zeigten sich Zusammenhänge hinsichtlich der vermehrten Rußbildung im transienten Betriebspunkt, die im stationären Vergleichspunkt aufgrund der geringeren Rußbildung nicht erkennbar waren. Zudem wurde ein Auszug aus einem WLTC-Mitschrieb des korrespondierenden 4-Zylinder-Motors mit viel Rußpartikelemissionen extrahiert und am Endoskop-Motor appliziert. Dabei handelte es sich um ein Tip-In mit Miller-Zyklus und asymmetrischen Ventilhüben. Die phasengemittelten Vektorfelder der stationären und transienten Betriebspunkte zeigten eine gute Übereinstimmung. Gleiches gilt für die gemittelten Kenngrößen der Flammenausbreitung und des Rußeigenleuchtens. Bei der Korrelationsanalyse wurden wiederkehrende Zusammenhänge zwischen den innermotorischen Prozessen festgestellt, die wie folgt beschrieben werden können: Die Strömung im Bereich unterhalb der Zündkerze und zentral oberhalb des Kolbens beeinflusst die Flammenausbreitung in Richtung der Zylinderoberflächen. Ein frühes Auftreffen der Flamme an den jeweiligen Zylinderoberflächen begünstigte dort die Entstehung von Ruß. Im Rahmen der Arbeit konnte im Rahmen der Messunsicherheit kein Einfluss der Parametervariationen entlang der transienten Manöver auf die phasengemittelten Vektorfelder festgestellt werden. Mit dem Wissen über unterschiedliche Zusammenhänge der innermotorischen Prozesse entlang eines transienten Manövers gilt es bei der Motorapplikation für jeden Zyklenbereich entlang eines Manövers die Ladungswechselstrategie und die Motorapplikation hinsichtlich der Rußpartikelemission zu optimieren

Pretty Understandable Democracy 2.0

The technological advance is entering almost all aspects of our everyday life. One interesting aspect is the possibility to conduct elections over the Internet. However, many proposed Internet voting schemes and systems build on unrealistic assumptions about the trustworthiness of the voting environment and other voter-side assumptions. Code voting -- first introduced by Chaum [Cha01] -- is one approach that minimizes the voter-side assumptions. The voting scheme Pretty UnderstandableDemocracy [BNOV13] builds on the idea of code voting while it ensures on the server-side an arguably practical security model based on a strict separation of duty, i.e. all security requirements are ensured if any two components do not collaborate in order to violate the corresponding requirement. As code voting and strict separation of duty realizations come along with some challenges (e.g. pre-auditing phase, usability issues, clearAPIs), the goal of our research was to implement Pretty UnderstandableDemocracy and run a trial election. This paper reports about necessary refinements of the original scheme, the implementation process, and atrial election among the different development teams (each team being responsible for one component)

Investigation of in-cylinder soot formation in a DISI engine during transient operation by simultaneous endoscopic PIV and flame imaging

A single-cylinder full-metal engine with a real combustion chamber geometry was used to investigate particulate number emissions resulting from transient engine operation. The formation of particulate number emissions depends on mixture formation influenced by the in-cylinder flow and injection, and the formation of fuel films on the in-cylinder walls. For the investigation of this multi-parameter process, simultaneous endoscopic PIV and combustion visualization were applied. Hence, the measurement techniques allowed the investigation of in-cylinder flow, flame propagation, and soot formation. The test rig was modified to apply a generic load step and a realistic tip-in with Miller cycle. The reproducibility of the engine parameters during the transient allowed statistical analysis and the comparison between steady-state operating points. Cause-and-effect chains concerning the formation of soot are concluded by correlation analysis of parameters extracted from the flow field, the flame propagation and the soot luminosity

Multi-parameter imaging of in-cylinder processes during transient engine operation for the investigation of soot formation

Transient engine operation of direct-injection spark ignition engines can result in high particulate number emissions. To investigate the causes of soot formation, an engine test rig was developed to perform detailed measurements of real transient operation. For this purpose, a single-cylinder full-metal engine with a real combustion chamber geometry was equipped with minimally invasive optical accesses. Simultaneous high-speed endoscopic PIV, spray visualization, and combustion imaging were applied to investigate the in-cylinder processes in detail. Endoscopic PIV was first compared in the central symmetry plane with classical PIV performed at the equivalent optical engine at steady-state operation for verification. Then the engine parameters of a tip-in performed by the corresponding four-cylinder engine, which led to high particle number emissions, were applied to the single-cylinder engine. The engine parameters were in a good agreement and particle number emissions due to the maneuver were within the same range of several 10^6 #/cm3. In total, 19 repetitions of the tip-in maneuver were analyzed with respect to the in-cylinder processes and repeatability of engine parameters. Furthermore, the in-cylinder flow field during the late compression stroke, flame propagation, and soot luminosity of single cycles during the tip-in indicated cause-and-effect chains for the formation of pool fire and soot at the injector tip. The direction of the flow below the spark plug influenced the direction of flame propagation. An early arrival of the flame enhanced the formation of soot from fuel films formed on the piston surface or at the injector. In engine applications, counter measures can be applied to reduce the particle number emissions when accounting for these indicated cause-and-effect chains

Multi-parameter imaging of in-cylinder processes during transient engine operation for the investigation of soot formation

Transient engine operation of direct-injection spark ignition engines can result in high particulate number emissions. To investigate the causes of soot formation, an engine test rig was developed to perform detailed measurements of real transient operation. For this purpose, a single-cylinder full-metal engine with a real combustion chamber geometry was equipped with minimally invasive optical accesses. Simultaneous high-speed endoscopic PIV, spray visualization, and combustion imaging were applied to investigate the in-cylinder processes in detail. Endoscopic PIV was first compared in the central symmetry plane with classical PIV performed at the equivalent optical engine at steady-state operation for verification. Then the engine parameters of a tip-in performed by the corresponding four-cylinder engine, which led to high particle number emissions, were applied to the single-cylinder engine. The engine parameters were in a good agreement and particle number emissions due to the maneuver were within the same range of several 10⁶ #/cm³. In total, 19 repetitions of the tip-in maneuver were analyzed with respect to the in-cylinder processes and repeatability of engine parameters. Furthermore, the in-cylinder flow field during the late compression stroke, flame propagation, and soot luminosity of single cycles during the tip-in indicated cause-and-effect chains for the formation of pool fire and soot at the injector tip. The direction of the flow below the spark plug influenced the direction of flame propagation. An early arrival of the flame enhanced the formation of soot from fuel films formed on the piston surface or at the injector. In engine applications, counter measures can be applied to reduce the particle number emissions when accounting for these indicated cause-and-effect chains

Investigation of in-cylinder soot formation in a DISI engine during transient operation by simultaneous endoscopic PIV and flame imaging

A single-cylinder full-metal engine with a real combustion chamber geometry was used to investigate particulate number emissions resulting from transient engine operation. The formation of particulate number emissions depends on mixture formation influenced by the in-cylinder flow and injection, and the formation of fuel films on the in-cylinder walls. For the investigation of this multi-parameter process, simultaneous endoscopic PIV and combustion visualization were applied. Hence, the measurement techniques allowed the investigation of in-cylinder flow, flame propagation, and soot formation. The test rig was modified to apply a generic load step and a realistic tip-in with Miller cycle. The reproducibility of the engine parameters during the transient allowed statistical analysis and the comparison between steady-state operating points. Cause-and-effect chains concerning the formation of soot are concluded by correlation analysis of parameters extracted from the flow field, the flame propagation and the soot luminosity

Use of a robotic RNA purification protocol based on the NucliSens® easyMAG™ for real-time RT-PCR detection of hepatitis A virus in bottled water

International audienc