Soil Degradation of Parthenin—Does it Contradict the Role of Allelopathy in the Invasive Weed Parthenium hysterophorus L.?

The invasive success of Parthenium hysterophorus L. is thought to be partially attributable to allelopathy mediated by the plant metabolite parthenin. To assess the ecological significance of parthenin release from plant material, its persistence and phytotoxicity in soil was studied. Results show parthenin is rapidly degraded with an average DT ₅₀ of 59 h under standard experimental conditions. Degradation was delayed in sterilized soils, at lower soil moisture, and higher parthenin concentrations. Higher temperatures, higher CEC_pot/clay content of soils, soil preconditioning with parthenin, and P. hysterophorus infestation accelerated degradation. Physico-chemical and biological processes are, therefore, expected to govern the fate of parthenin in soil. Parthenin exhibited low soil phytotoxicity and did not accumulate over time. Along with the indicated reduction in bioavailability and development of hormetic effects, results suggest that for parthenin to have detrimental allelopathic effects, it requires high P. hysterophorus densities that result in high soil levels of parthenin and soil conditions that favor the persistence of parthenin. In light of this, the ecological significance of parthenin is discussed.     

Airflow rates by combined natural ventilation with opposing wind—unambiguous solutions for practical use

Analysis of possible airflow rates by combined natural ventilation with opposing wind in rooms with two openings shows multiple solutions, instability and hysteresis. In this paper, it is analysed to what extent these phenomena should be considered under practical conditions. The analysis shows that unambiguous solutions can be obtained if difference between indoor and outdoor temperature is known at start, i.e. when heat sources are switched on and ventilation openings are opened. Discontinuities in airflow rates occur under certain specific conditions.     

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Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties

Background  

Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles.     

Identity- und Access-Management mit EAI-Konzepten und -Technologien

Zusammenfassung  In diesem Beitrag wird die Idee eines EAI-basierten Identity- und Access-Managements (IAM) vorgestellt. Konzepte, Vorgangsweisen und Technologien aus dem Bereich Enterprise Application Integration (EAI) dienen dabei als Ausgangsbasis. Aktuelle Standards und ihre Unterstützung durch Integrationswerkzeuge werden diskutiert. Dipl.-Ing. (FH) Karl Flieder ist hauptberuflich mit Integrationsaufgaben in der Automobilindustrie betraut. Nebenberuflich widmet er sich der Lehre an der FH Joanneum.     

Longitudinal control algorithm for automated vehicle merging

This paper considers longitudinal control of automated vehicle merging in a mathematical approach for automated highway systems. Merging manoeuvre is defined as one vehicle in the merging lane to be inserted in the middle between two vehicles in the main lane at fixed merging point which is the intersection of those two lanes. The main lane vehicles can change speed. To achieve this, the merging vehicle must properly adjust its speed and acceleration such that it reaches the merging point at the right time with the same speed and acceleration as the main lane vehicles. This problem is a little similar to but different from the well-known missile interception problem. The longitudinal control problem is proposed for different road layouts, based on which a unified mathematical model is established. Then a new concept, virtual platooning, is introduced, which effectively avoids a two-point boundary value problem . Based on this concept, an analytic solution with mathematical proof is provided. It is also discretized as a recursive algorithm for real-time use. A dynamic real-time simulation is published at PATH website. This algorithm has been successfully implemented with automated cars.