Thermal comfort of novel low-momentum ventilation concepts for passengers in long-distance trains

Thermal comfort is essential to increase the modal share of rail transport by attracting more passengers. In this study, three novel low-momentum ventilation concepts were analyzed regarding the thermal comfort of railway passengers and compared to a conventional ventilation setting. Using an experimental approach, objective measurements of climate parameters and subjective assessments from 146 test subjects in a generic train compartment were analyzed. Results revealed significant differences in perceived thermal comfort among the four ventilation settings. Subjects reported comparatively higher thermal comfort in hatrack integrated low-momentum ventilation and hybrid ventilation (HV) than in cabin displacement ventilation (CDV) and microjet ventilation (MJV). Vertical temperature stratification was strongest in CDV, leading to losses in the comfort of the lower body parts. In MJV, some temporary and local exceedances of air velocities were observed, which contributed to lower comfort evaluations at heads and shoulders. For all ventilation settings, warmer air temperatures were preferred. Our findings demonstrated that subjective comfort assessments reasonably complement earlier results derived from thermal manikin studies. Therefore, low-momentum ventilation, especially in terms of HV, has the significant potential to improve thermal conditions for long-distance journeys in passenger rail cars

Synthesis and catalytic performance of cesium and potassium salts of aluminum substituted tungstoborate for pyrolysis of polyethylene waste to petrochemical feedstock

Polyoxometalates have gained considerable attention as a catalyst. Herein, we are reporting tungstoborate based catalysts for the conversion of waste polyethylene to liquid fuel. Novel cesium and potassium salts of aluminum substituted tungstoborate Keggin compounds were synthesized by a simple one-pot method and successfully characterized by FTIR, SEM-EDX, thermal analysis, NMR and single-crystal XRD. Catalytic cracking of waste polyethylene by using our prepared aluminum substituted catalysts (CsAB) showed 97% polymer conversion producing80 wt% of liquid hydrocarbons with a negligible amount of solid residue (∼3 wt%), significantly lower compared to thermal cracking where 22 wt% residue was produced. The oil collected at optimum reaction conditions (0.5 catalyst/polymer ratio and 3 h reaction time) was subjected to GC-MS analysis. The results showed that oil produced in catalytic cracking has a high selectivity to gasoline range hydrocarbons while thermal cracking showed selectivity to higher hydrocarbons (C13–C26). Olefin selectivity was also more prominent in catalytic cracking. Hence cesium and potassium salts of aluminum substituted tungstoborate are excellent catalysts for acid-catalyzed polymer cracking reactions to produce value-added petrochemicals

Adaptive Evolution of Staphylococcus aureus during Chronic Endobronchial Infection of a Cystic Fibrosis Patient

The molecular adaptation of Staphylococcus aureus to its host during chronic infection is not well understood. Comparative genome sequencing of 3 S. aureus isolates obtained sequentially over 26 months from the airways of a cystic fibrosis patient, revealed variation in phage content, and genetic polymorphisms in genes which influence antibiotic resistance, and global regulation of virulence. The majority of polymorphisms were isolate-specific suggesting the existence of an heterogeneous infecting population that evolved from a single infecting strain of S. aureus. The genetic variation identified correlated with differences in growth rate, hemolytic activity, and antibiotic sensitivity, implying a profound effect on the ecology of S. aureus. In particular, a high frequency of mutations in loci associated with the alternate transcription factor SigB, were observed. The identification of genes under diversifying selection during long-term infection may inform the design of novel therapeutics for the control of refractory chronic infections

Verantwortungsbewusster Umgang mit IT-Sicherheitslücken : Problemlagen und Optimierungsoptionen für ein effizientes Zusammenwirken zwischen IT-Sicherheitsforschung und IT-Verantwortlichen

IT-Sicherheitslücken in Hard- und Software betreffen private, unternehmerische und auch staatliche Systeme. Sobald eine Ausnutzung der Lücken technisch möglich ist, stellen sie eine Bedrohung für die IT-Sicherheit aller Beteiligten dar. Konkret betroffen sind Bürger:innen und Unternehmen als Nutzende, Hersteller von Soft- und Hardware sowie staatliche (kritische) IT-Infrastruktur. Es ist daher im gesamtgesellschaftlichen Interesse, die Zahl der ausnutzbaren Sicherheitslücken so gering wie möglich zu halten. Dieses Whitepaper führt in die rechtlichen und praktischen Probleme der IT-Sicherheitsforschung ein. Zugleich zeigt es vor allem rechtliche Auswege auf, die perspektivisch zu einer rechtssicheren IT-Sicherheitsforschung führen

Undergraduate students' adoption of handheld devices and Web 2.0 applications to supplement formal learning experiences: Case studies in Australia, Ethiopia and Malaysia.

This paper reports research into undergraduates’ adoption of handheld devices as supplementary learning tools. Students enrolled in Engineering and Business in Australia, Africa and Malaysia volunteered to participate in a study of their use of the HP iPAQ from mid-2005 to late-2006. The Business students were located in Perth (Australia) and in Addis Ababa (Ethiopia), and the Engineering students were located in Perth and Miri, Sarawak (Malaysia). Researchers observed and analysed the participants’ commencing levels of technology adoption, and then there subsequent adoption and perceptions of the usefulness of the iPAQ. Students did not recommend the iPAQ for learning because, using Roger’s reasons for adoption, it was trialable and observable but it failed to meet expectations. The Ethiopian students who, despite undeveloped ICT infrastructure, were most open to continue to experiment and persist with the device regardless of trying circumstances

Effekte von individueller Kontrolle auf thermischen Komfort: Ein psychologischer Effekt oder einfach die „richtige“ Temperatur?

Dass die Kontrolle über die klimatischen Bedingungen in Innenräumen einen positiven Effekt auf den subjektiven Komfort hat, gilt als erwiesen. Dennoch ist bislang offen, ob der Komfortgewinn auf die wahrgenommene Kontrolle zurückzuführen ist, oder auf die Möglichkeit, individuell passende Bedingungen einzustellen. In der vorliegenden Studie wurde diese Fragestellung in einem experimentellen Design für Bahnreisende untersucht. Für insgesamt 84 Versuchspersonen wurden in einem ICE-Versuchsträger Winterbedingungen simuliert, so dass Infrarot-Heizpaneele und Sitzheizungen sinnvoll genutzt werden konnten, um die mittlere Innenraumtemperatur den eigenen Präferenzen entsprechend anzupassen. In einer zweiten experimentellen Bedingung waren dieselben Heizelemente aktiv, konnten jedoch nicht individuell geregelt werden. Stattdessen wurden die zuvor eingestellten Bedingungen für alle Versuchspersonen automatisch wiederhergestellt. Die Ergebnisse zeigen, dass die individuelle Kontrolle über die Klimabedingungen keine Auswirkung auf den thermischen Komfort hatte. Lediglich in Bezug auf das körperliche Wohlbefinden ergab sich ein tendenzieller psychologischer Effekt zugunsten der Kontrollmöglichkeit. Insgesamt war der Effekt individueller Kontrolle gering, sie wirkte nur als Mittel zum Zweck, um eine passende Temperatur einzustellen. Für die Klimatisierung im Fernverkehr lässt sich schlussfolgern, dass der individuelle Komfort der Reisenden nicht gesteigert werden kann, indem den Reisenden – zum Teil wartungsintensive – Kontrollmöglichkeiten über die Temperatur zur Verfügung gestellt werden. Neue Klimatisierungskonzepte könnten sich vielmehr auf die Entwicklung individueller Komfortzonen konzentrieren, in denen das individuell „richtige“ Klima bereitgestellt wird

Effects of personal control for thermal comfort in long-distance trains

As a result of its low environmental impact the railway system is the prime candidate to enable domestic and continental mass passenger mobility. One important aspect determining the attractiveness of rail journeys is the thermal comfort that is provided in a passenger rail car. Newer approaches focusing on the improvement of thermal comfort in passenger rail cars are based on the idea to employ personalized comfort zones. It is generally assumed that individual control over indoor climate settings contributes to the passengers’ thermal comfort. The studies presented here further examine this assumption by considering the concept ‘‘thermo-specific self-efficacy” (specSE) as psychological construct in the context of thermal comfort in a railway car. Two studies with 11 human subject test runs including 172 subjects in total were performed in a mock-up of a passenger rail car. Environmental climate conditions in the mock-up were controlled and measured. It was found that specSE can be considered as a distinct construct and that it contributed substantially to the prediction of thermal comfort and climate satisfaction. In addition, it moderated the effects of available and exercised control. The presented results expand upon earlier findings for the concept of personal control and confirm the role of specSE for thermal comfort predictions

Influence of personal control on thermal comfort: A psychological effect or just the “right” temperature?

Personal control of indoor environmental conditions has a positive effect on subjective thermal comfort. This has been demonstrated in various field and laboratory studies for both office buildings and long-distance transport. It is still an open question whether the perceived higher comfort was due to the belief of being in control or to the option to set the right temperature. The study was designed to examine this question in an experimental setting in a long-distance train serving as test facility. Winter conditions were simulated for 84 subjects in total who could use infrared panels and seat heating elements, respectively, to adjust their individually preferred temperature in addition to the centrally controlled air condition of the train. In a second experimental condition, the same heating elements were in operation but subjects were not able to control them. Instead, the individual settings of the previous condition had been restored for each subject and were administered again without the subjects’ awareness. Thus, both conditions were identical except for the level of personal control. The personal control of heating elements versus the automated settings did not lead to any differences in the perception or evaluation of temperature, air draught or thermal satisfaction. Thus, the psychological effect of being in control was near zero. The "right" thermal settings appeared to be crucial, whether controlled by the subjects or by an external protocol

Increasing Thermal Comfort through Individual Heating Options in a German ICE Long-Distance Train

The European Commission aims at being competitive and sustainable in passenger transport. One determinant for rail attractiveness is the passengers’ thermal comfort. Commonly, comfortable climate environments are realized by optimizing central HVAC systems. This approach neglects individual preferences and might not satisfy all passengers at best. In this paper, we investigated whether different heating devices enabling individual temperature control could be used to create a climate situation in which the passengers’ satisfaction was at least as high as in global baseline conditions, although mean air temperature was 2K cooler. The study took place in a representative ICE laboratory carriage that served as stationary test facility. In total, 84 subjects participated in four test trials. Comfort ratings were assessed via established standardized questionnaires. Results revealed that comfort variables did not differ depending on the type of temperature control. It was concluded that usage of individual heating devices compensated for 2K lower temperatures in the individual conditions but did not increase the thermal comfort. Thereby, all heating devices were perceived as being equally comfortable. Moreover, it became obvious that it is not the psychological effect of having control which accounts for the perceived comfort, but it is more important that the temperature is regulated exactly the way a passenger wants it. This finding points to options for future comfort improvements by implementing locally personalized climate environments